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Extension of abalone fishery research to industry and others by way

Contents

1. ao 1991 SADF A LTS CN E NA Mo 7 We AbaSim Reading ANZ N N Appendix C Further reading Clavier J and O Richard 1985 Etude sur les ormeaux dans la R gion de Saint Malo Association pour la mise en valeur dy litteral de la C te D Emeraude Dinard 285pp Cox K W 1962 California abalones family Haliotidae Fisheries Bulletin of the Californian Department of Fisheries and Game 116 1 131 Gulland J A 1985 Fish stock assessment a manual of basic methods FAO Wiley Series on Food and Agriculture v 1 Wiley Interscience Chichester 223pp Sullana J A 1955 Fish Population Dynamics Wiley Interscience Chichester 422pp Hilborn R and C J Walters 1987 A general model for simulation of stock and fleet dynamics in spatially heterogeneous fisheries Canadian Journal of Fisheries and Aquatic Science 44 1366 1369 Mottett M G 1978 A review of the fishery biology of abalones Washington Department of Fisheries Technical Report 37 81pp Prince J D 1989 The fisheries biology of the Tasmanian stocks of Haliotis rubra Ph D Thesis Univ Tasmania 174pp Prince J D T L Sellers W B Ford and S R Talbot 1988 Recruitment growth mortality and population structure in a southern Australian population of Haliotis rubra Mollusca Gastropoda Marine Biology 100 75 82 Shepherd S A 1973 Studies o
2. FISH INSIGHT a unit of the South Australian Department of Fisheries specialises in providing a high quality user interface for models developed by others The interactive graphics interface makes the models easily accessible provides new insights into their complex dynamics and allows communication of this understanding to non specialists AbaSim is one such program It simulates what happens to a population of abalone when it is fished by divers As the user you act as the manager of the fishery Each year you can change the minimum size limit and adjust the fishing pressure The catch and profitability of abalone divers harvesting the reef respond to your controls You immediately see the effects on the population as coloured dynamic graphics easily understood by non specialists The model is based on real data and uses information about growth reproduction mortality movement patterns and diver behaviour Although AbaSim is based on an abalone population it illustrates types of behaviour experienced by species other than shellfish For example it is easy to demonstrate sustainable development growth overfishing recruitment overfishing the value of age sampling cyclic behaviour rehabilitation of a fish stock etc SharkSim is another interactive graphics model It is based on Australia s southern shark fishery Commissioned as an agent for change it was used by scientists and managers i
3. Game 1 Even though the divers almost have to give away their catch to the fish factory they do well enough to commit more of their time to diving for abalone Other local divers hear about what s going on and join in 7 Set effort at 100 and press Enter for 2 more years 8 Increase the effort to 200 for 2 years after that We record the sequence of controls you have entered up to now as 16507 26 8b100 46 2 5 2002 Co A dot means that the value is the same as in the previous year Catches increase in proportion to the effort Catch rates remain fantastic n fact the catch rates are so stable that some inexperienced fishery biologists are convinced that the stock must be massive or at least extremely resilient Advisers make some quick calculations and announce to the media that the local economy will be saved by this liquid goldmine People quit their jobs to collect abalone full time Amateur divers all over Australia plan to do likewise 9 Increase the effort to 300 for the next 2 years and raise it to 400 for the 2 years after that 7 300 8 9 400 10 Catch rates CPUE start to decline a little indicating that the previously unfished stock has at last been dented But they have only fallen about 10 so there doesn t seem any cause for concern Most fishery biologists would expect CPUE to fall to about 30 50 of the virgin level before the stock is reduced to the level at which it will produce
4. You will also discover if you have not already done so that the model will allow you to re write history At any time you can move the time cursor along the time axis using the lt and arrow keys This can be used not only to perform surveys at a certain point in time but to change management measures in retrospect If you collapse the stock with a certain level of quota you can scroll back through time put in a different strategy and then try again You can do the same with age limits Note that you cannot switch between quotas and effort control in the same scenario When you press G Go the model will continue the simulation using the management measures last used Stop by pressing any key You can save games i e simulations or scenarios by using the Save command You can replay them at a later date by using the Load command You should now have all the skills necessary to operate the simulator Concise operating instructions are presented in Chapter 6 o oo o o o o 0 o qo o o o o o oo qo qo e qc o 1991 SADF dE dd AbaSim Lessons 5 Lessons In this chapter we discuss some aspects of the behaviour of the simulator We believe they are worth noting for the insight they give us about abalone fisheries and the way they illustrate some of the basic concepts of fisheries management 5 1 Abundance and catch rates O
5. aggregate in the central cell of the reef Figure 1 shows a typical stock density pattern abalone per square metre produced by the model It is very similar to that observed on George III Rock where 50 of the abalone were found to be clumped in only 14 of the reef area e gt o o o o o o 0o o o o o o o o o o o o o o O o Gl G l ol ol ol Hll Gl oll Gl o o o o o G ol G ol 1991 SADF di E dd N AbaSim Abalone biology di OE ca ee To date no one has shown that the number of adult abalone in an area determines the number of young abalone that grow up there In scientific language no one has proved or disproved that there is a relationship between the size of the breeding stock and the number of animals that subsequently recruit to the fishery On AbaSim Reef we avoid this difficulty by specifying that the number of young abalone is related to the number of adults This relationship is shown in Figure 4 where a density of about 1 7 abalone per square metre produces the greatest number of one year olds at the start of the following year Above this level the number declines Appendix B 5 120 Figure 4 Reproduction how a 100 spawning stock aged determines the number of one x o 80 year olds produced ay at the start of the 5 60 following year o 2 AbaSim Reef Se O S 4 oe gt me 0 O 0S 0 15 20 25 38 35 40 Spawning
6. Resist this temptation Read the first three chapters of this manual first and then play the games described in chapter 4 You will learn about abalone and fisheries management and be entertained on the way The AbaSim program and manual were designed for a wide audience We do not assume you know anything about abalone or about personal computers PC s But you will need to have access to a computer compatible with an IBM PC 286 with a colour VGA screen preferably with a maths coprocessor AbaSim simulates what happens to a population of blacklip abalone Haliotis rubra on a reef when it is fished by abalone divers The model uses information about the growth reproduction mortality and movement patterns of abalone and the behaviour of divers It represents scientists understanding of the dynamics of a fishery based on the abalone that live on a small reef off Tasmania The fishery based on this stock was studied as part of a major research program carried out in Australia between 1984 and 1987 led by Dr Jeremy Prince Chapters 1 2 and 3 introduce you to abalone biology abalone divers and fisheries management If you want more details about the models and their relationship to research results consult the small print in Appendix B the references Appendix C or write to the authors Scientists are still investigating many of the issues discussed Chapter 4 Games is the most important in the manual Use it to discover
7. The first intrepid divers have put on their primitive wetsuits and ventured out from the boat ramp on a perfect calm day late in summer They stop at one of the first reefs they find and start looking for abalone which they have heard can be sold at a nearby fish factory Despite their lack of experience their catch rates are fantastic and considering the low level of effort the catch is good 6 Catch rates catches and effort are shown on the bottom graph on your screen Catch rates CPUE are shown by the red line Effort is shown by the blue dashed line Catch is shown by the solid green area The Age limit you are using age 7 years is shown by the broken yellow line Make sure you note the age structure of the catch now as this may be useful in making future decisions The age structure of the catch each year is shown at the top right corner of your screen where the different age classes are colour coded Note that the older abalone are very important in the catch abalone 15 years old and older make up most of the catch weight You are fortunate that a biologist was waiting at the boat ramp to sample and age the catch to provide this information This didn t happen in real life and the technique for aging abalone wasn t discovered until about 25 years after the Australian abalone industry started eeoeeeee e888 e e o co coco co o oo coco cc coa o qo 1991 SADF AbaSim
8. behaviour It is based on real data The AbaSim program and manual were designed for a wide audience To use it you do not need computer experience or knowledge about fisheries or abalone The manual tells you about abalone biology fisheries management and the Australian fishery on which the model is based An easy going commentary leads you through scenarios relates them to real world experiences and leaves you to manage the fishery on your own Later it explains what happened and why and draws lessons relevant to the real world The Australian Fishing Industry Research and Development Trust Fund FIRDTF supported the development of AbaSim and benefits from its distribution AbaSim should be considered a cost effective and time saving method of improving the performance and understanding of participants in the fisheries management process The successful management of fisheries is vital not only to the people whose livelihood depends on them but also to a world of dwindling natural resources Fisheries managers are at the forefront of learning how living resources can be developed in a sustainable way AbaSim is designed to help managers understand how fisheries behave and how managers actions can affect them e Continued and profitable harvesting of natural resources requires an understanding of the dynamics of the fish stock a commercial fishery s core asset This requires knowledge of biology and of population dynamic
9. do anything about the fishery If you stop the industry growing now you might never know how productive it could be Go ahead and see what happens At least then you will know 10 Set effort to 500 for 1 year 11 500 What happened Nothing much CPUE continues its slight downward trend just as you d expect for a virgin stock being fished down to a productive level Things seem to be settling down nice and gently The 7 8 year olds are now twice as important in the catch as any other age group Does this mean the fishery is becoming much more productive or is it just becoming more reliant on the newest recruits Remember these recruits were born 7 8 years ago The divers continue to tell you that the number of abalone on the reef is declining which agrees with the CPUE data So what are you going to do next year Let the fishery continue growing 11 Set effort to 600 and press Enter 12 600 Now you are on your own Should the fishery be allowed to continue growing or should you take steps to control it It s your decision You know how to increase or reduce effort You can also change the age limit by using the plus and minus keys If you crash the stock and don t wish to wait for it to recover press C to Clear the simulation Put the same initial scenario shown over page as GAME 1 into the simulator and try again This time before you start playing do a couple of research surveys 12 Using the lt and g
10. sure the catch was the best size or in the best condition for the market During the 1950s and 1960s it was discovered that market forces could destroy fish stocks Managers began to realise that fishers with fully depreciated fishing gear could economically fish stocks to commercial extinction and keep them there If a stock is fished too hard catches will eventually decline Seeking optimal levels of exploitation fisheries scientists developed theories about surplus yield and maximum sustainable yield Many concentrated on studying growth and mortality The results were often used in yield per recruit analysis which determines how the yield of an average fish is affected by its size at first capture and by fishing pressure Despite the complex mathematical models that have been applied to analysing fish populations recently uncertainty and risk still dominate fisheries stock assessments and consequently the advice scientists provide to managers 3 1 Stock indicators Even harder than developing theoretical models of fisheries is trying to find out what is actually happening underwater Scientists have enough trouble measuring things that stay still on the land such as trees let alone animals that roam around at the bottom of the sea The first approach to measuring fish stocks is direct Scientists go out and count fish But surveys are slow and expensive And it is only possible to measure one small part of
11. the maximum sustainable yield However if you have been watching the age composition of the catch you will have seen it change quite dramatically The 7 8 year old abalone are now the most common age class This suggests either that reproduction rates have increased greatly due to fishing down the old stock the stock has become more productive or the older abalone have been fished out Have you been watching the window in the top left hand corner of the screen This is a diver s eye view of the reef which covers the entire area of AbaSim Reef The colour coding is the same as for the catch composition The divers report that there are definitely fewer abalone now than before but they cant be exact about how many e o o gt o o o o o o o o o o o o o o o Oo H o ol H ol Gl H Hl ol Ol Gl Gl lH ol ol ol ol o ol Gl G o o o o o o o o o o o o o OH ol ol ol o 1991 SADF ad O gi CR dd ee AbaSim Game 1 EN You will also have noted that the divers only fish certain areas of the reef only those cells are displayed There are abalone on the rest of the reef Things can t be too bad when the divers don t have to use the whole reef The existing divers must still be pretty happy about the stock because they are prepared to put more and more effort into the fishery New divers also continue to enter the fishery Should you
12. the user cannot change the model parameters and thereby examine sensitivity AbaSim was not intended to be a scientific tool the assumptions of the model are not clearly stated in the documentation The documentation was aimed at non specialists Small print and references are provided for those who seek them AbaSim gives the false impression that fisheries management is simpler than it is in reality In particular the model does not take account of random variation or environmental effects and it is difficult to communicate uncertainty The scope of the product had to be limited and a complicated model would have alienated many potential users The ideal presenters of AbaSim are scientists who use it to communicate general principles and then qualify the model in relation to the real world 3 4 Future development A list of possible improvements to the package has been compiled and is continually being updated in response to user feedback The information would be incorporated into the specification of a future product if feasible and justified During 1992 the SA Department of Fisheries will market AbaSim seeking the best mixture of means of distribution e g mail order agents distributors publishers The marketing project will be reviewed at the end of 1992 and decisions made regarding further distribution future product development and the feasibility of the department commercialising such products A s
13. 20 8000 40 2 5200 66 7 300 8 9400 100 110600 12 600 e o o o gt o o o o o o o o Ol l Ol l Hl Oll ll Hl Gl Ol Hl Gl Hl ol l ol l o oH Gl o Gl ol ol oo o o ol l o ol ol ol ol olo 1991 SADF AbaSim Game 2 Game 2 Bonanza The second scenario is typical of a reef that gets discovered in an established fishery The reef has escaped the attention of the abalone divers for years It has been so close to home that everyone assumed some one else would have discovered it by now or the diving conditions are generally so bad that no one has bothered to have a good look at it or it is so remote that improved technology has only just made it feasible for fishing Whatever the reason the fully developed fishery has finally caught up with this reef The word is out Gold rush fever has hit the diving community Everyone is sick of scratching around on their old tired patches The runabouts are racing towards the new reef Press the Q key to start a new scenario and switch the simulator into Quota mode In this mode you control the catch directly but cannot control effort Set the quota for this area of virgin reef at the maximum 100 tonnes annum Use the Enter key to make this catch for the first 4 years REI 7 Bile Shek Ba Normally the pressure on a new reef would b
14. EXTENSION OF ABALONE FISHERY RESEARCH TO INDUSTRY AND OTHERS BY USING INTERACTIVE EDUCATIONAL COMPUTER SOFTWARE FIRDC Project 89 8 FINAL REPORT to FISHERIES RESEARCH AND DEVELOPMENT CORPORATION by SOUTH AUSTRALIAN DEPARTMENT OF FISHERIES 19 December 1991 FINAL REPORT FIRDC Project 89 8 SECTION 1 PROJECT TITLE EXTENSION OF ABALONE FISHERY RESEARCH TO INDUSTRY AND OTHERS BY USING INTERACTIVE EDUCATIONAL COMPUTER SOFTWARE SECTION 2 OBJECTIVES The objectives of the originally proposed project were To make recent advances in abalone research accessible to the Australian abalone industry To improve management of abalone fisheries through increased knowledge and understanding To develop new techniques of applying the results of fisheries research FIRDC granted only a small proportion of the funds originally applied for A year later after viewing a prototype it granted supplementary funding To complete the software that now exists in prototype form To edit and produce a user manual from the existing draft To design an educational computer based training package To present the model at the 1st World Fisheries Congress A proposed workshop tour to transfer the results to industry was not funded SECTION 3 RESULTS 3 1 General The project has resulted in the production and distribution of the AbaSim software package two copies of which accompany this report Appendix A copied from the user ma
15. aaaantastic he games are very easy to play tructions are easy learn and apply tons few and easy get used to The creen ts brilliant Carol Moore Senior Computer Systems Officer is program comes ser than anything 2lse I have seen to revealing how alone populations behave It is evolutionary and exciting oresby Shepherd Biologist HERIES MANAGERS ISHING INDUSTRY ONSERVATIONISTS FISHERIES DEPARTMENTS SCIENCE COMMUNICATORS toverseas order torin APPENDIX B pes im Order Form Abasim PIS INSIGHT A GRAPHIC FISHERY Learning tool for fisheries management The AbaSim computer program simulates a fishery based on a shellfish population that lives on AbaSim Reef Try being its manager Your aim is to preserve the fish stock and develop it sustainably While playing the easy to use computer program you will learn important principles of fisheries management and be entertained at the same time AbaSim simulates what happens to a population of abalone when it is fished by abalone divers Each year you can change the minimum size limit and adjust the fishing pressure The catch and profitability of abalone divers harvesting the reef respond to your controls You immediately see the effects as coloured dynamic graphics easily understood by non specialists You can also carry out research surveys The model uses information about growth reproduction mortality movement patterns and diver
16. ader range of fisheries magement issues the model is unsurpassed Jon Mackie past orcement Officer Customer Hotline in Australia Telephone 08 226 0633 Int 618 226 0633 j AbaSim is an educational tool The manual describes the latest knowledge about abalone biology and fisheries management Key references are listed The model is suitable for university tutorial sessions during which students can either follow the book s scenarios or be asked to experiment with the model and thereby gain Insights based on their experiences It has relevance in a wide range of subjects e g biology environmental studies and resource economics mathematics communications design and graphics design Schoolteachers can easily use the model to demonstrate some fundamental lessons about the behaviour of fisheries 10 year olds can easily understand the screens and play the game after a few minutes tuition e AbaSim offers a completely new view of the dynamics of an exploited fish stock Dynamic visualisation and interactive graphics techniques reveal what is happening to the population structure when you manage the stock in different ways You use AbaSim like a flight simulator gaining a feeling for the sensitivity of the dynamics and insights into the behaviour of the nonlinear system The screen displays offer new visualisations of complex relationships previously only accessible through numbers and equations Unfortunately you cannot c
17. ample again watching the Biomass This time keep effort at 600 for years 13 to 17 Then set the effort to O and keep pressing Enter You would think that the biomass would start rebuilding immediately But it does not Even without any fishing it keeps declining The full effect of a declining biomass takes some time to work its way through the stock because it takes seven years for an abalone to grow to a size at which it becomes vulnerable to fishing This time lag can also work to the manager s advantage Play GAME 2 again Compare it with the first exercise Note how much easier it is to restore the stock to its full productivity Interestingly in this second exercise a similar tonnage is taken from the stock in a shorter time You would expect this to cause greater damage to the stock than a similar tonnage over a longer time The reason it does not is that there are still large numbers of immature animals in the stock when management is introduced The paradoxical effect of the time lag between spawning and recruitment may have been what saved the South African abalone fishery In the space of about _ years SouthAfriea seemedto remove aimost its the entire breeding stock This resulted in a spectacular decline in the annual catch from approximately 3 000 tonnes in 1965 to less than 1 000 tonnes in 1970 In response the authorities reduced the catch quota to 800 tonnes You might think that this collapse signalled the end of the stoc
18. ams Gavin Wright Marko Zagar The project was funded by South Australian Department of Fisheries Fishing Industry Research and Development Trust Fund The authors Tasmanian Fisheries Development Authority research Tasmanian Abalone Divers Research amp Development Trust Account research Fishing Industry Research Trust Account research ete a de CREA CREE EH KH OSCR HKG RS BEH HM Se RBC Oe E KER eee SM ME TO DO NS Contents ANTZA NZ N Contents Start here About this manual AbaSim and models 2 l Abalone biology 4 2 Abalone divers 8 3 Fisheries management 10 3 1 Stock indicators 10 3 2 Fisheries management tools ll 3 3 Managing a fishery iz 4 Games 14 Game 1 Gradual development of a fishery 15 Game 2 Bonanza 19 Game 3 Pulse fishing 21l 5 Lessons 23 5 1 Abundance and catch rates 23 5 2 Time lags 24 5 3 Size Age limits 25 5 4 Quotas 26 5 5 Research surveys 26 6 Operation 6 1 Computer hardware required 2i 6 2 Installing the program 2i 6 3 Starting and stopping the program n 6 4 The main screen 28 6 5 Keyboard control 29 6 6 Saving and loading scenarios games 30 Appendices A Ordering the software service 3 B Details of the models 32 C Further reading 34 l 1991 SABF obeyoeg Jo 9SN Tenuen gO squsdquos S3uUsousbpoTMOUXODY VY XIGNdddV Start here Start here About this manual Usually when people buy a new computer game they cannot wait to try it But before you use AbaSim please
19. any fish stock how to relate the results to the total stock is a constant problem We avoid this difficulty at AbaSim Reef where the survey data shown on the screen are very accurate If you conduct a research survey in any year you will see exactly how many abalone of each age class were on the reef at the end of the previous year You can decide for yourself what it means e o o o o o ee o ee o o o o o o o o o o o o cc o o ll q Gl co qo co o 1991 SADF a E dd di AbaSim Fisheries management The second approach to monitoring fish stocks is less direct the researcher collects the fishers catch and effort records which is a relatively simple and cheap exercise This approach is based on the assumption that the catch rate or CPUE reflects the size of the stock It seems logical that if fishing has reduced the number of fish in a stock by half you should expect CPUE to be halved Many fish stocks are monitored on this principle AbaSim shows you catch and CPUE information that you can use to help you monitor the simulated abalone stock 3 2 Fisheries management tools Generally fishery managers use four main tools to control exploitation 1 Protect part of the fish stock by imposing minimum size limits to ensure only the older fish are caught In AbaSim we implement this control by setting a minimum Age at which abalone can be caught 2 Limit how hard fisher
20. apse suddenly They just decline slowly This may offer comfort to managers of abalone fisheries but the disadvantage is that a recovery will also take a long time 5 3 Size Age Limits The simulator also shows some of the advantages and limitations of managing the fishery by imposing size limits Where there is very little knowledge size limits can be introduced to the fishery as a conservation measure that is easy to apply If stock conservation is your only concern an abalone fishery can be managed with size limits alone No controls on effort or catch are necessary But did you try managing the population with size limits and leaving the quota or effort control extremely high You would have noticed that the divers are the ones who suffer for catch rates plummet with that type of management So if you are interested in the economics of your fishery direct controls on catch or effort are more efficient methods of controlling exploitation o o o o o o o o o o o o amp 1991 SADF ade CE q CE q AbaSim Lessons At this point we should highlight a difference between this simulation model and the real world While the principles noted above are applicable to the real world the use of size limits in abalone fisheries is in fact far more complex than this model suggests In the real wor
21. by age category Top right Definition of age categories Biomass Abalone population biomass Middle by coloured age category Outcomes and Catch CPUE Bottom Controls Effort Age limit A vertical white cursor time cursor showing the Point in time being viewed can be moved left and right by using the arrow keys The catch histogram shows the catch weight by age category from the previous year s fishing Standard colour code Colours used to code Age Categories can be seen at the top right of the screen If you are not using a standard VGA screen configuration the colours listed below may be different Refer to the on screen colour codes Colour Age Category Dark blue 3 4 years Blue 5 6 Light green 7 8 Green al Yellow 11 12 Orange 13 14 Red 15 Colour Outcome or control Units Green shaded area Catch tonnes Yellow dashed line Age at first capture years Blue dashed line Effort hours fished per year Red line CPUE Catch Per Unit Effort kilograms per hour 1991 SADF 6 5 Keyboard control AbaSim Operation You can see a list of these on the computer screen at any time by pressing H for Help or F1 Fishing Enter Advance one year G Go advance till interrupt Controls T 4 Adjust effort quota Shift 7 Shift 4 Fine adjust effort quota Adjust age limit Movement gt lt Move cursor forward or backward 1 year Shift
22. ce US 450 5 program diskettes 5 manuals site licence Licences HALF PRICE to educational institutions and course attendees Single user US 97 50 O Site US 225 d currency convertion rate and use the US Australian hange rate at time of mailing Australian O Additional manuals For site licences only nerican Express O Visa O MasterCard US 25 each 10lder s name Total US Disk size O 5 O 3 10lder s signature Postar US o Cu 7 t card no Expiry GATE rms verten tate US US 3 optional TEEETETTLELET ET gana totat uss sie wee would prefer to make my payment as a bank draftin r currency see below for list of acceptable currencies and dded US 3 currency conversion rate then converted the Total at exchange rate at time of mailing tralian Dollar Austrian Schilling Belgium Franc Danish mer Dutch Guilder French Franc German Mark Hong Kong lar Irish Pound Japanese Yen New Zealand Dollar Iva Fe Postage Airmail Add one of the folowing amounts depending on number of books in your order 1 book US 10 2 or 3 books US 20 4 to 7 books US 30 8 to 10 books US 45 Delivery Allow 21 days Customs duty We ll make every effort to ensure your copies of AbaSim reach you quickly and take every care to protect you from customs duty However we cannot q raiavrantaa that vaner JAN a lt a o tmnnart 6 AP END x C Article for American Fisheries Society Computer Users Section News leito
23. e divers their families and representatives Garis Alexander Alan Armstrong Janine Baker Kevin Branden Tracy Brothers Barry Burr Merle Carmmiss Steven Clarke Rob Day Lesley Fairbairn Ludmilla Filadelh Shaun Forbes Wesley Ford Ray Hilborn Patrick Hone John Jefferson John Johnson Jan Kirkegaard Neil Klaer Gordon Kuckhahn Rob Lewis Vivienne Mawson Carol Moore John Nowland Mick Olsen Sharon Palmer Russ Reichelt Natalie Schenk Scoresby Shepherd Hosi Stankovic Simon Talbot Richard Tilzey Angelo Tsolos Mike Walker Carl Walters Meryl Williams Gavin Wright Marko Zagar The project was funded by South Australian Department of Fisheries Fishing Industry Research and Development Trust Fund The authors Tasmanian Fisheries Development Authority research Tasmanian Abalone Divers Research amp Development Trust Account research Fishing Industry Research Trust Account research dr E AbaSim ae Start here ad O gs E oe computer Instead free your imagination you are a god playing with the world Well not quite but you are the manager of a fishery And your computer is a terminal which reports what is happening in the world When using AbaSim keep asking the question What happens if and use the model to find out Before making the model simulate a situation try to predict what will happen and why The gap between your expectation and what happens will stimulate you to think fur
24. e expected to decline after a few years as the stock is reduced and divers go back to their home patches However in this case we assume that quotas have been introduced into the other parts of the fishery and this reef is part of an area that has been left out of the quota system Keep the catch at 100 until the 8th year INO Th Ol OME BC 0 The divers say there has been a massive reduction in stock density Did you watch the catch composition change Note The diagonal hatching indicates that the height of the bar is slightly above the scale of the graph Catch rates have dropped about 40 but they weren t very reliable last time were they Are you going to be brave and manage the stock without surveys as real fishery managers often do It s cheaper that way Besides you can always do surveys next time Maybe you should close the reef completely But if you do that how will you know when to start fishing again Surveys are good for this purpose But a complete closure and surveys will be costly and make you unpopular Maybe you should cut the catch savagely and risk the wrath of the oe o qo ooo o qa O 1991 SADF Cn a AbaSim NE a ee Game 2 a O Na divers You could always raise the age limit Then again you could do what many others have done nothing Try to manage the fishe
25. elect Quota mode choose a level of quota and the computer will keep the divers happy In summary when playing AbaSim you can easily control three management tools by using the keyboard 1 Age at first capture 2 Fishing Effort 3 Catch Quota 3 3 Managing a fishery Now you know how to adjust the three management controls So how do you manage a fishery How much fishing effort should you set What size of quota How much stock should be left in the water How should you adjust your decisions in the light of the stock indicators you are monitoring In theory the answer is simple you must leave enough abalone in the water to produce the maximum sustainable yield for AbaSim Reef To achieve this fisheries biologists have several rules of thumb some of which have been likened to vaguely stated wisdoms of witchcraft In the past most fishery managers tried to proceed with caution controlling the expansion of the fishery if they could and watching the stock indicators for signs of trouble i e They adopted a cautious suck it and see approach Professor Carl Walters 1986 argues that this approach has led to the collapse of many fisheries and moreover the cautious approach will have prevented us from learning about the stock in the meantime He proposes a new approach called Adaptive Management He argues that wherever possible fisheries should be divided into parts and managed experimentally Different management techni
26. ertain interesting features of abalone fisheries In chapter 5 we discuss some of the points raised by these scenarios in more detail You will gain more from the simulation model if you let your imagination run free and imagine that the computer is just reporting to you what is actually happening in the real world 1 Switch on your computer Section 6 1 2 If you need to install the software Section 6 2 3 Start the program by entering the AbaSim directory and typing ABASIM Enter Section 6 3 Relax and enjoy it Enter the simulated world e gt o o o o o o o o o o o o o oo o o co qo o o ll o coco 1991 SADF di E dd AbaSim Game 1 aa esa i Game 1 Gradual Development of a fishery This exercise describes a situation where the fishery begins at a low level and steadily builds up It is similar to the overall pattern of effort on most of Australia s abalone fisheries and particularly on the more accessible reefs 1 Set the level of effort at 50 by pressing the up arrow key 7 once Watch where the bar is on the Effort scale It is at 50 hours per year 2 Press Enter and watch what happens 3 Press Enter again 4 You have just applied 50 hours of fishing effort to AbaSim Reef over years 1 and 2 5 You can reduce effort with the J arrow key Pressing the Shift key with the arrow keys allows fine adjustment The fishery has just begun
27. f its virgin level During this collapse catch rates declined rapidly as did effort After the collapse when effort had declined catch rates improved significantly The total catch did not So the simulator confirms what abalone biologists have long known and which was reiterated at the First International Symposium on Abalone Biology ua ae to eu saias as 4 AO sis 8 6 O 1991 SADF Oey ee N AbaSim Lessons Fisheries and Culture held in 1990 in Mexico Catch rates can be used as an index of abundance only when they are declining sharply Stable or rising catch rates cannot be taken to indicate anything about stock abundance The effect observed in the simulator is due to the aggregation of abalone and the ability of divers to target these aggregations Catch rates decline because divers are catching them more quickly than the animals can aggregate This is shown in GAME 2 where catch rates increase when quotas are reduced even though the abundance of abalone continues to decline Note that we are not necessarily saying abundance does not affect catch rates What we are saying is that abundance is not the most important influence on catch rates 5 2 Time lags A feature shown by the simulator but which is less immediately evident is the time lag caused by the years taken between spawning and recruitment to the fishery This can be most clearly seen if you go back to GAME 1 page 18 Begin the first ex
28. feeding Abalone are vegetarians In Australia they seem to prefer small fleshy red seaweeds which they will actively search for and graze on They will also catch bits of broken seaweed drifting past If a group of abalone were placed in one of the 100 x 100 m cells that make up AbaSim Reef this type of movement would lead them to spread over time throughout all 25 cells Research has shown that there is more movement when there is not much food In the model the amount of food in any cell depends on how many abalone are there Appendix B 3 The second type of movement is directional and may be related to abalones breeding or feeding behaviour Some populations apparently move towards the oncoming swells others form aggregations along the sandy edges of reefs possibly because currents concentrate food supplies there and still others move towards shallower depths Reproduction Abalone are broadcast spawners Males and females gather together and at some signal start releasing eggs and sperm into the water The eggs mix with the sperm in the water and are fertilised The eggs hatch into larvae This process is most likely to be successful if the aggregations at breeding time are large Possibly the directional movement described above plays a part in forming these aggregations On AbaSim Reef in the simulation model abalone are assumed to be more likely to move towards the shallow water than deeper water Appendix C 4 so they
29. gt or Shift lt Move cursor forward or backward 10 years Home Cursor to start year End Cursor to end year Quit Esc Stop AbaSim Mode E Switch to Effort mode Q Switch to Quota mode C Clear game View B Biomass switch on off R Research survey A About screen H Help screen Files L Load game from disk S Save game to disk P Print screen to HP Paintjet printer o o o o o o o ao o o 1991 SADF Oe a AbaSim Operation 6 6 Saving and loading scenarios games You can store scenarios as computer files by using the Save command When you type S the screen prompts you to enter the name of a file in which to store the game currently being displayed on the screen Type in a name of fewer than eight characters and press Enter You can Load simulations that were previously stored by typing L You will be offered a list of existing files Use the arrow keys and PgDn and PgUp keys to highlight the file you want to retrieve and press Enter The scenario you want will be loaded AbaSim is supplied with three scenarios already loaded They are the games you played in Chapter 4 i e GAME 1 GAME 2 and GAME 3 All files are saved to and retrieved from the same directory as that from which the AbaSim program was run O 1991 SADF AbaSim Orders Appendix Ordering the software service AbaSim is available in single copies or as site licences Please contact us if y
30. hange the underlying model parameters John Tonkin who designed and programmed the screens is an award winning Australian computer artist AbaSim is an example of how artists can apply their unique communications skills e IBM PC 286 compatible colour VGA screen e maths coprocessor optional increases speed Computer hardware required Developed by FISH INSIGHT Contact FISH INSIGHT South Australian Department of Fisheries GPO Bax 1625 Adelaide SA 5001 Australia Customer Hotline For details or a quotation on FISH INSIGHT services and products please write to us Or call our Facsimile 08 226 0664 Int 618 226 0664 To order your copy of AbaSim please complete and send or fax this order form to FISH INSIGHT T INITIALS OR CHRISTIAN NAMES SURNAME POSITION ORGANISATION NAME OF SITE LICENCE FOR SITE LICENCES ONLY ADDRESS TELEPHONE FACSIMILE EMAIL m is HALF PRICE to educational institutions and course attendees Please enquire about special prices for Australian abalone divers s I would like to order a copy of AbaSim o not wish to place an order at this time however please add name and address as indicated above to your mailing list 1 enclosing a bank draft US or see list of acceptable currencies below de payable to FISH INSIGHT in the sum of 2ase charge my credit card in Austral n Dollars only O Single user licence US 195 1 program diskette 1 manual single user licence O Site licen
31. he bottom graphs your chances of managing the fishery well are slim 1991 SADF AE di DE A AbaSim Operation oe SD cqi 6 Operation 6 1 Computer hardware required To run AbaSim you need a computer compatible with an IBM PC with a 286 chip e g IBM AT 386Sx 386 486 etc and a colour VGA screen The software will run much faster if you use a maths coprocessor 6 2 Installing the program AbasSim is supplied on a 720kB 3 5 or 5 25 diskette To install AbaSim onto a hard disk insert the supplied diskette into an external diskette drive and type A INSTALL Enter or B INSTALL An installation program will run When it asks type the name of the directory into which the programs will be loaded C ABASIM is offered as a default You can also run the program directly off a diskette by logging the diskette drive as the default directory 6 3 Starting and stopping the program 1 Enter the AbaSim subdirectory e g Type C gt CD ABASIM Enter 2 Type ABASIM Enter 3 Stop the program by pressing Esc o eee gt gt o o o o o o o co O o o oo co o as 1991 SADF de E dE RO AbaSim Operation 6 4 The main screen The AbaSim screen displays the following information Screenarea Variable displayed Location on screen Reef map Abalone spatial distribution Topleft by age category Catch Catch weight
32. ht of an abalone at various E ages AbaSim Reef ap 45 Age years Mortality The abalones main defences against a hungry world are their thick shell and their strong grip on rocks As the young ones have not developed these they are extremely vulnerable to predators which is probably why they hide amongst the boulders of the reef As they grow larger and their shells strengthen they move onto more exposed rocks where they can be found more easily by divers Figure 3 shows that their natural mortality rate declines with age Appendix B 2 1 0 Figure 3 Proportion of abalone of each age surviving to the 0 8 following year in an unfished population AbaSim Reef 0 6 n DA 0 2 0 0 o ooo qo o o o o o o o o o o o o o o o oo o ooo cc oco ao 1991 SADF qi a ee AbaSim Abalone biology a Na Recruitment to the fishery Blacklip abalone in Tasmania mature between the ages of 5 and 12 years About half of the population is mature by 7 or 8 years When they reach maturity the abalone move out into the open where they become vulnerable to divers In fisheries terms they become recruits to the fished population In the model all the abalone mature and recruit to the fishery when they are 7 years old Movement patterns The abalone at George III Rock had two patterns of movement The first was random shuffling apparently related to
33. k But that was not the case the fishery 1991 SADF ENSA O NE AbaSim Lessons has remained stable at 800 t annum since 1971 It would seem that while the adult stock animals 7 years old was severely depleted by the initial over exploitation there were sufficient immature animals left to rebuild the stock after the introduction of proper management A different effect of the delay between spawning and recruitment can be seen if you play further with the third example Pulse fishing can very easily generate a fluctuating population If you watch the Biomass you will see that fluctuations in the population are driven by previous fluctuations in spawning stock caused by periodic heavy fishing However if you did not have the benefit of seeing the biomass and were dependent on surveys you would have difficulty distinguishing between pulses of recruitment generated 7 years before and genuine stock recovery resulting from more recent changes to management The importance of timing to management can also be shown in other ways It is possible to create scenarios where delaying the implementation of a management policy by one year means the difference between collapsing a stock and rebuilding it Try it The crucial element in all this is the time between the spawning of a year class and its recruitment to the fishery the generation time Because abalone have a relatively long generation time abalone stocks do not coll
34. ld fishery managers must manage a large number of reefs as a single fishery Unfortunately the growth and breeding characteristics of abalone usually vary considerably between reefs Populations with the best growth rates will be the least protected by any particular size limit Appendix B 10 The impact of this is that a single size limit is likely to over protect the areas least needing protection and concentrate effort on the areas most susceptible to over exploitation It would be possible to use different size limits to protect each of the populations but the data requirements and enforcement problems would most likely be prohibitive 5 4 Quotas The simulator highlights some interesting limitations of management by using quotas Probably the most significant is the damage that can be caused by having an inappropriately large quota It is very easy to collapse the stock with quotas This is because there is no control on effort no matter how scarce the abalone become the divers continue working to fill their quota Controlling effort would be more effective because the number of abalone declines and falling catch rates make further fishing less attractive 5 5 Research surveys AbaSim demonstrates the value of research surveys especially at the start of a fishery If you do not have any estimates of the age structure of the population i e Biomass on the screen and rely solely on the catch and effort information presented in t
35. ly and the biologists to manage the fishery better A model is a purposeful representation of realty When you stop using the simulator remind yourself that the AbaSim model is just a model and not an exact duplicate of the real world It represents some of what we currently believe about abalone fisheries it is not an actual abalone stock It is limited by the extent and accuracy of research to date our overall understanding and what is feasible to model Models such as AbaSim are useful for developing understanding but not necessarily for making accurate predictions about the real world The purpose of this model is to gain insights and to find out where our understanding about the real world is weak and should be improved The successful management of fisheries is vital not only to the people whose livelihood depends on them but also to a world of dwindling natural resources Fisheries managers are at the forefront of learning how living resources can be developed in a sustainable way AbaSim is designed to help managers under stand how fisheries behave and how managers actions can affect them Enjoy using AbaSim Please don t spoil the game for others by showing them what they should discover for themselves Your suggestions for improvements are welcome Philip Sluczanowski Producer 30 August 1991 e gt o o o a C q a a 8 amp 8 8 a ee ee a us 1991 SADF Fa
36. n public meetings to convince industry and the public of the need for urgent and significant changes to management of the fishery It did so by effectively communicating scientists best understanding of the state of the stock and the likely consequences of alternative management actions Scientific visualisation and interactive games are rapidly growing areas of science made possible by recent advances in computer technology They will change the ways in which we view data and analyse relationships Dr Philip Sluczanowski FISH INSIGHT South Australian Department of Fisheries 135 Pirie Street Adelaide South Australia Postal address GPO Box 1625 Adelaide SA 5001 Australia Telephone 61 8 226 0633 Facsimile 61 8 226 0664 FISH INSIGHT South Australian Department of Fisheries A Graphic Fishery Jeremy D Prince Philip R Sluczanowski John Tonkin CAR OR an CO qo Peida nee ey Warning Unauthorised copying of the AbaSim software or manual is unethical and illegal Published by the South Australian Department of Fisheries GPO Box 1625 SA Australia 5001 First published 1991 Copyright South Australian Departinent of Fisheries 1991 AbaSim A Graphic Fishery ISBN 0 7308 1899 3 Software patent applied for All rights reserved Acknowle dgments John Tonkin a computer artist programmed the computer game We thank for their assistance support and inspiration Abalon
37. n southern Australian abalone genus Haliotis I Ecology of five sympatric species Australian Journal of Marine and Freshwater Research 24 217 257 Shepherd S A M J Tegner and S A Guzman del Proo 1992 Abalone of the world biology fisheries and culture Blackwells Oxford 744pp Starfield A M K A Smith and A L Bleloch 1990 How to model it problem solving for the computer age McGraw Hill New York 206pp Walters C J 1986 Adaptive management of renewable resources Macmillan New York 374pp 1991 SADF
38. ne in that cell will move in one of the four cardinal directions out of the cell during each year Of course some abalone in the surrounding cells will also be moving into the cell so that the net effect may not be so great The directional movement of abalone has been observed by some scientists to be dependent on the size or age of the abalone However for simplicity it is assumed that on AbaSim Reef only the mature animals move and that amongst these animals movement doesn t depend on either age or size To achieve this the model assumes that no more than 24 of abalone move from any one cell towards a shallower cell each year regardless of the number of abalone in that cell Only sideways or downwards movements vary with the number of abalone in the cell This may seem strange but it is possible that at high densities large abalone will interfere with small abalone and the smaller abalone will suffer At high densities the crevices under the rocks may become too full and small abalone may be pushed out to where they become more vulnerable to fish crabs or starfish or to large abalone which may accidentally smother crush or even eat them It should be remembered that on AbaSim Reef density and movement of adults interact This interaction has been adjusted so that adults will only keep aggregating while their density is less than the best density for breeding At densities of 1 5 2 0 abalone per square metre which is the bes
39. ne of the first things you would have noticed was how unreliable catch rate CPUE is for telling you how much biomass you have left There are specific simulations which illustrate this point 1 Put the model into Effort Mode and switch on the Biomass view Set effort at 500 with a 7 year Age limit Keep pressing Enter and watch the CPUE and the biomass Before long you will see the biomass crashing Note what CPUE is doing It hardly changes Watch how low biomass needs to fall before CPUE responds sharply Note that when CPUE starts falling it does so catastrophically If you haven t done something about the fishery before then say goodbye to your career as a fishery manager 2 Put the simulator in Quota mode and switch on the Biomass view Replay GAME 2 where the quota was set at 100 t annum Note how sharply CPUE and biomass are declining Perhaps CPUE declines a little more slowly but on the whole you d say it was showing you pretty well what was happening After 8 years of this quota reduce the quota by 50 What do CPUE and biomass do now CPUE increases sharply while biomass keeps falling In this respect the simulator seems to reflect reality quite well In the Mexican fishery extremely high catches of about 3 500 4 500 tonnes of abalone meat per annum were made through the 1950s 60s and the early 70s Effort was high but catch rates also remained high In the late 1970s the catch collapsed and by the early 1980s it was about 10 o
40. nger abalone now dominate the catch However the divers view of the reef hasn t changed much What are you going to do now Are you going to accept the challenge and continue managing it with pulses of effort Or are you going to try and force it to be a normal fishery which is fished in every year Experiment on your own Use the e and keys to examine the age composition of the catch in several years After you ve destroyed yet another abalone stock and are prepared to move on well let you into the secret of good fisheries management Game 3 Pulse fishing In Effort mode 1 8007 20 36 4800 5 0 66 7 800 8 0 9 10 600 o o ooo o o o cao qo o o o o co o oa o o o o oco oco O o o o O 1991 SADF GR O N AbaSim Game 3 dd E da Perfect knowledge of the stock and The ability to undo past mistakes If you press B you will switch the computer model into Biomass mode Pressing B a second time will switch this mode off In Biomass mode the age structure and abundance of the abalone stock will be automatically displayed in the Biomass area in the middle of your screen In the top left hand corner of your screen you will also be shown the distribution of the abalone over the entire reef not just where the divers are diving The Biomass mode can be turned on or off at any time so you can use it at the end of a scenario if you want to know what really happened
41. nual lists acknowledgements shows the contents of the manual and describes how to use the package The benefits offered by the software package are listed on the order form Appendix B Additionally a prototype of an educational computer based training package called AbManager has been produced in collaboration with Dr Rob Day of Melbourne University who will trial it in 1992 The World Fisheries Congress was postponed for a year due to the Gulf War However AbaSim has been widely shown to North American and European fisheries scientists see below 3 2 Distribution The AbaSim package was released in September 1991 Following consultation with the South Australian Abalone Divers Association it was decided that an effective way of distributing the package to the Australian abalone industry was to deliver six copies of the package to the abalone industry associations in various states This has been achieved via state fisheries departments each of which was requested to maintain one copy in their library Additional copies have been distributed to other Australian fisheries departments and training institutions These organisations were encouraged to obtain additional copies for use in staff training and to assist in further distribution In August 1991 FIRDC agreed that the South Australian Department of Fisheries sell AbaSim commercially FIRDC will receive 10 of the sale price The decision will be reviewed after three years A
42. ou develop and document useful scenarios Your comments and suggestions are most welcome Contact FISH INSIGHT South Australian Department of Fisheries 135 Pirie Street Adelaide South Australia Postal address GPO Box 1625 Adelaide SA 5001 Australia Telephone 08 226 0633 International 61 8 226 0633 Facsimile 08 226 0664 International 61 8 226 0664 soeere ee neeqeoete e ee2eetirefeteeosweiteprpe eneieteteeetee wetetece eeng 46ertreeseesteeebe doeaeweekkrezstewtvreeters ss wwteeeoee e4oeeteew ssess teeetkken nsce 8 ss 1991 SADF aos E a SE a a N Z Nee Sd AbaSim Details CONA ee A Appendix B Details of the models B 1 B 2 B 3 B 4 B 5 The simulation model only keeps track of 15 year classes but the oldest year class is actually an accumulation of even older year classes which are assumed to have the same body weight and mortality rates This gives the average probability that an abalone of any age will survive until the next year The table is based on southern Tasmania data and some conjecture Annual survival is assumed to increase from approximately 30 in the youngest age class to 90 in the oldest age classes In the model it is assumed that the amount of food in any cell will depend on the number of abalone in that cell A cell with many abalone will have less food than one with fewer abalone When there is a high number of abalone in a cell up to 24 of the abalo
43. p clunkers i e catch abalone off the rock and put them into their net bags eee ee o o o Jc o o o 1991 SADF asi aee E q AbaSim ANS Abalone divers TASTAN S Research conducted on George HI Rock found that divers covered an average of 1 128 square metres of reef each hour with 100 efficiency Appendix B 8 A study in Victoria found that the average diver took 5 1 seconds to handle each abalone Appendix B 9 Figure 5 shows how a diver s catch rate and therefore his or her profitability depends on the different densities of abalone he or she finds 450 Figure 5 How catch rate CPUE depends on stock density 400 me rememce ca AbaSim Reef TET awe Ane TERS ol et ee d CE a 1 5 3 5 4 0 Catch rate kg per hour Stock density abalone per sq m ANZ E NN AbaSim Fisheries management 3 Fisheries management Until the Second World War little attempt was made to manage fisheries It was believed that market forces would manage renewable resources The theory was that as an overexploited fish stock declined the fishery would become unprofitable and fishers would leave the fishery giving the fish stock a chance to recover Management measures such as size limits or seasonal closures were used for economic rather than conservation purposes for example to make
44. ques should be deliberately applied ranging from complete protection to very heavy exploitation Then if parts of the fishery decline the managers will at least be able to compare those sections and the techniques used to manage them with the remaining productive areas and learn from the comparison Walters argues that when a fishery managed as a unit declines all that is learnt is that the fishery should have been managed differently 1991 SADF id E ge AbaSim Fisheries management ian a ds E a Now you know Why you should manage the abalone fishery of AbaSim Reef it will probably collapse if you don t How to monitor the state of the stock research surveys and CPUE What management techniques you can apply Age limits Effort and Quota Your career as a fisheries manager is about to begin O 1001 SANF Cat OUR ee AA AbaSim Games 4 Games This chapter has been written to entertain and teach you In it you will be introduced to AbaSim and to the art of simulation We shall lead you step by step through some scenarios games and at the same time teach you how to use the simulator We suggest that you work through this chapter carefully and thoroughly Use this chapter to learn how to use the simulator Use Chapter 6 for reference The three exercise games provided with the software have been chosen because they are typical of what has happened within the Australian industry and each highlights c
45. r FLYING FISHERIES Pilots and fisheries managers both have to control complex dynamic systems in fluctuating environments The better they understand the behaviour of the systems they are trying to manage i e aeroplane or fishery the more effective they are Scientists and engineers usually lead the development of understanding through research experimentation and design But is this level of understanding sufficient and how best to communicate it An aeroplane designer is familiar with the equations and performance levels describing a plane s behaviour and can explain the likely consequences of using different controls under various conditions But can he she fly a plane Certainly not based on this theoretical level of understanding To fly a plane a pilot needs to experiment with the system to gain a feeling for its dynamics sensitivity and responsiveness The only way to do this is to interact with it through an effective user interface This could be either a flight simulator or the aeroplane itself Interactive graphics models of fisheries offer similar advantages You can combine the equations describing a fishery into a computer program which simulates certain aspects of a its behaviour You can then outfit this model with a user interface that allows the user to easily interact with it and immediately see the consequences of different management actions The user can fly the system and so learn about it
46. ry from year 9 onwards Experiment on your own You can Load GAME 2 automatically by pressing L using the arrow keys to select the scenario and pressing Enter When you ve destroyed the stock to your satisfaction proceed to the third and final scenario where you will he told the secret of good fisheries management j t e ame onanza In Quota mode EOOD AG Cr HC Ules Thoas Gleam af o o ooo eee o o o o o o o o o o o o o o o gt gt gt o gt gt gt 0 1991 SADF AbaSim Game 3 Game 3 Pulse Fishing This scenario is similar to the situation at many of the more distant abalone reefs in Australia Because of their remoteness they are not fished constantly but experience periodic pulses of heavy fishing pressure In some fishing zones periodic closures are used as a management strategy areas of reef are closed and opened periodically to the industry the aim being to maintain high catch rates when divers do fish Switch the simulator back to Effort Mode by pressing E Apply 800 maximum effort in year 1 and don t fish 0 for the next 2 years Apply 800 in year 4 and don t fish 0 in years 5 and 6 Repeat this pattern for years 7 8 and 9 Reduce the intensity of the pulse in year 10 and only apply 600 Have you been watching the stock indicators Catch rates have stepped down steadily and you
47. s AbaSim teaches these subjects simply e It is important that the public appreciates what is meant by sustainable management Then they can respond when non sustainable practices occur AbaSim can convey an understanding of the basic issues to a wide audience The user can demonstrate alternative sustainable fishing policies and compare their benefits e Staff of a fisheries department appreciate the relevance of their work better if they understand the basics of fisheries management AbaSim has been trialed as a training tool to achieve this Managers enforcement officers administrators communicators and scientists all found the experience instructional and satisfying A person training with AbaSim needs about 2 4 hours alone with a computer e The model illustrates types of behaviour often experienced by species other than abalone AbaSim can be easily used to demonstrate some of these e g sustainable development overexploitation time lags eradication of a stock s spawning potential age sampling cycles rehabilitation etc You can also use AbaSim to illustrate analogies in wildlife and other areas of natural resources management EDUCATORS AND STUDENTS ERIES SCIENTISTS IMPUTER ARTISTS certainly learn a fair bit of how a very can collapse 1 how it can also wed Sometimes 2ar ts all it takes save the fishery Angelo Tsolos Senior Statistics Clerk I think that as a teaching aid for ducing students he bro
48. s part of an overseas trip in September 1991 the project leader Dr Philip Sluczanowski demonstrated AbaSim at the annual conferences of the American Fisheries Society the UK Marine Conservation Society and ICES He also showed it to key officers at FAO Rome UNESCO Paris and RRAG London A number of sales have resulted and discussions are being held with potential overseas agents and distributors AbaSim was purchased and used as part of an FAO training project in Fiji in November 1991 3 3 Feedback The response of everyone who has seen or used the package confirms that it meets the original objectives of the project Commercial and recreational fishers conservationists fisheries managers science communicators research managers and senior scientists have been particularly enthusiastic about the benefits of the technology for providing new insights into the behaviour of fisheries systems that must be managed based on limited information see Appendix C Beverton Pope Shepherd Holden Megrey Edwards Garcia Troost and Griffith praised the model They see the main uses of such models as communicating key and difficult fisheries management concepts to non specialists e g sustainable development growth and recruitment overfishing time lags age sampling cycles rehabilitation A user has remarked that It s a great little minister convincer Some scientists suggest that AbaSim is not as useful as it could be because
49. s with the worst diving conditions will have the greatest abundance of abalone and potentially the highest catch rates So how a diver chooses between reefs will have a large effect on catch rates The diver s choice will be largely determined by how desperately he or she wants to maximise catch rates So in the real world catch rates may be determined by many things besides the size of the stock To take the diver s choice into account the model reduces catch rates in the shallow area to 15 30 kg per hour less than the catch rate possible in deeper water This difference in fishing pressure and catch rate is maintained through the program B 8 That is an average abalone diver would take one hour to find all the legal sized abalone in an area of 34 x 34 metres B 9 All these factors can be put together into an equation to calculate a catch rate for any density of abalone CPUE d xP Q h x dx Py CPUE stands for Catch Per Unit Effort catch rate d is the density of abalone in numbers per square metre P is the fishing power of the divers in square metres effectively swept per hour and h is the handling time required to capture each abalone B 10 Abalone that grow slowly have more opportunities to spawn before they become vulnerable to fishing than do fast growers Since fast growers are also more likely to offer profitable fishing they are more at risk from overfishing e eee gt o o oc o o o
50. s work We call this Effort control mode 3 Limit the size of the catch which is called Quota control mode 4 Close some areas to the fishery This mode is not used in AbaSim because AbasSim Reef is too small The abalone at AbaSim Reef can t be caught before they are 7 years old because they are hidden under boulders and divers usually do not carry crowbars However you can change this Age anywhere between 7 and 15 years The model uses an age limit rather than a size limit as would happen in practice because we assume that all the abalone on the reef grow at the same rate You should remember that the abalone on AbaSim Reef breed at age 7 so if you allow the divers to fish hard with a low size limit they could fish out virtually all the breeding abalone Fishing effort can be limited by restricting the number of fishers shortening the fishing season or preventing them from using more efficient gear The main difficulty with these methods is that fishers are very clever at finding ways of working harder or becoming more efficient You don t have this problem at AbaSim Reef If you set a level of Effort divers will keep to it E e e e a S a M a O O O l r a a a O n O O e O O a O O a a O O l O U U a a i O eee ss 8 sd OS ee ae AbaSim Fisheries management When you implement a quota system in the real world you must decide how to allocate it between fishers You don t have this problem at AbaSim Reef Simply s
51. stainable way AbaSim is designed to help managers under stand how fisheries behave and how managers actions can affect them Enjoy using AbaSim Please don t spoil the game for others by showing them what they should discover for themselves Your suggestions for improvements are welcome Philip Sluczanowski Producer 30 August 1991 ee oe eee o o o o o o o o o o o o o o o o o co o Ol o o qo qo 1991 SADF sad OE ae O AbaSim Abalone biology CN di a 1 Abalone biology This chapter describes the world being simulated by the AbaSim computer model It relates what is known about the abalone population on George III Rock and presents a mental picture of the reef with which you will be playing In many ways this population of abalone is like any other in the world However the model is specific to a reef in Southern Australia and it also takes no account of environmental or random effects These have to be accepted as limitations Location and habitat George III Rock is about 2 kilometres offshore in south eastern Tasmania 48 31 S 146 58 E The rock was named after wrecking a ship transporting convicts in 1834 It was nominated by local abalone divers as a good research site because it is typical of the commercial abalone beds in the area George III Rock is actually a reef about one kilometre square wi
52. stock density abalone per sq m It used to be thought that abalone larvae could be carried long distances from their parents and could settle onto reefs many kilometres from where they were spawned However recent research on blacklip abalone suggests that most of the larvae that settle successfully remain very close to the area in which they were spawned Appendix B 6 e e o o o o o o co q gif DES ee AbaSim Abalone divers 2 Abalone divers A fisheries biologist must be a student of human nature as well as of aquatic nature Describing how an abalone lives moves dies and reproduces is only half of the story the other half is the diver who catches them We must also describe how an abalone diver behaves if we want to be able to simulate an abalone fishery All fishers must decide where they should start fishing each day Most fishers those who aren t abalone divers will try a spot to see if it s going to be worth fishing After a while they wonder if they can do better elsewhere and decide whether to move It normally takes some time to work out where they ll do best for the day Fisheries biologists call this searching time A fisher s catch rate at the end of each day will depend in part on how much time is spent searching An experienced abalone diver arriving at a reef won
53. t arrow keys you can move the time cursor backwards and forwards along the time line Position the cursor under a year in which you would like to do a survey press R carry out a e eee 8 ao os 1991 SADF oe TOS ct ae o ae AbaSim Game 1 ai O ey o N Research survey The model actually does the survey at the end of the year before the one you select You can t do a survey in the first year An age and abundance profile of the stock will appear on the Biomass area in the middle of the screen The colour code is the same as for the catch composition Surveys of this standard are expensive to conduct People who manage budgets don t like them You shouldn t need more than two surveys before you start managing the fishery Make sure you return the time cursor to the latest year press End before proceeding With the benefit of the surveys see if you can improve your management of the fishery Use the e gt Home and End keys to move the time cursor to where you want to start fishing change the control and press Enter If you press the Shift key at the same time as an arrow key the cursor moves ten years at a time instead of just one When you are ready proceed to the second scenario Game 1 Gradual development of a fishery In Effort mode i 50 7
54. t density for breeding movement towards deeper water will be the same as towards shallow water Thus there will be no tendency to aggregate at these densities instead they will start expanding the area in which they aggregate If this didn t happen the abalone population could collapse itself by all abalone crowding into the shallow area and ruining their chance of breeding success It is possible that some similar mechanism exists in nature but this has yet to be proved Above a certain age the number of eggs produced by each mature abalone is more or less proportional to its body weight So the simulation model uses the total weight of mature abalone in each cell to calculate the number of one year olds produced Food supplies may also limit the size of a population ov ee 0 0 o o 00 o gq 1991 SADF do de AbaSim Details ad E ga DE B 6 On AbaSim Reef the level of recruitment within each 100 x 100 m cell is determined by the density of the breeding stock in the cell and is independent of the surrounding cells B 7 In this respect the real world is considerably more complex than the simulated world In the real world divers have many reefs to choose from These reefs will vary in depth and diving conditions and in the abundance and accessibility of the abalone Generally the deepest most inaccessible reef
55. t spend very much time searching he or she will quickly be able to tell if the reef is a good one simply by looking at the bottom Abalone divers soon learn where the good reefs are and where the abalone aggregate on them They also learn to predict where other concentrations might be on reefs they ve not tried before They do not therefore have long searching times But abalone divers must also take into account such matters as rough water strong currents poor visibility and depth These will affect their decision as to where to dive Abalone divers asked to fish down the abalone population on George III Rock fished the shallow water areas harder than the deeper areas Appendix B 7 For the simulation model we assume that divers spend so little time searching in their boat that we can ignore it All they do is anchor over the spot they ve chosen and jump into the water to start collecting abalone In the simulation model divers allocate their effort directly to the most preferred cell Their preference for each cell is based on the number of abalone in it and its depth Their preference for shallower cells creates differences in the catch rates similar to those observed during experiments at George III Rock When abalone divers jump on a spot and start swimming around their catch rate or catch per unit effort or CPUE will be determined by how fast they can cover an area of bottom and how quickly they can find and chi
56. th the rock from which it takes its name in the centre This rock is surrounded by bedrock covered by several layers of boulders Outside the central area in depths of 10 18 m the bottom is less complex and scattered boulders sit on the exposed bedrock or on sand The sea breaks regularly over the rock The reef is surrounded by sand The nearest reefs are two or three km away String kelp Macrocystis pyrifera grows on the reef below 11 m depth while bull kelp Durvillaea potatorum grows in the shallower areas In the computer simulation model the reef has been renamed AbaSim Reef and is a square made up of 25 cells each 100 x 100 m The central cell is the shallowest area of the reef and the outermost cells are the deepest Figure 1 100m lt gt Figure 1 Typical E Shallow density pattern abalone per square metre produced on Abasim Reef by the model Medium ie Deep 500m 1991 SADF ii E ee ae AbaSim Abalone biology Ages and growth Abalone are long lived marine snails Even in an exploited populations it is often possible to find individuals that are more than 20 years old see Appendix B 1 Abalone grow most rapidly when they are young and immature Growth continues after they mature but slows down because they put more of their energy into breeding Figure 2 shows the weight of individual abalone at different ages measured in the field and used in the model Figure 2 Growth weig
57. the dynamics of AbaSim Reef while playing Use this chapter to learn how to use the simulator Don t cheat or you ll miss some surprises Chapter 5 discusses useful lessons about fisheries that arise from Chapter 4 Chapter 6 tells you how to install the software and operate the program It explains how information is shown on the computer screen Use this chapter for reference When you use AbaSim try to forget you are sitting in an office with a 1991 SADF Pta bo Start here a a computer Instead free your imagination you are a god playing with the world Well not quite but you are the manager of a fishery And your computer is a terminal which reports what is happening in the world When using AbaSim keep asking the question What happens if and use the model to find out Before making the model simulate a situation try to predict what will happen and why The gap between your expectation and what happens will stimulate you to think further and generate greater understanding and insight Good fisheries biologists learn about a fishery by applying scientific research techniques studying the results and talking and working with fishers and other observers of the stocks They then build a picture or mental model of how the fishery works Most fishers do the same Both use these mental models to help them understand and predict what will happen in the fishery the fishers to help them catch fish effective
58. ther and generate greater understanding and insight Good fisheries biologists learn about a fishery by applying scientific research techniques studying the results and talking and working with fishers and other observers of the stocks They then build a picture or mental model of how the fishery works Most fishers do the same Both use these mental models to help them understand and predict what will happen in the fishery the fishers to help them catch fish effectively and the biologists to manage the fishery better A model is a purposeful representation of reality When you stop using the simulator remind yourself that the AbaSim model is just a model and not an exact duplicate of the real world It represents some of what we currently believe about abalone fisheries it is not an actual abalone stock It is limited by the extent and accuracy of research to date our overall understanding and what is feasible to model Models such as AbaSim are useful for developing understanding but not necessarily for making accurate predictions about the real world The purpose of this model is to gain insights and to find out where our understanding about the real world is weak and should be improved The successful management of fisheries is vital not only to the people whose livelihood depends on them but also to a world of dwindling natural resources Fisheries managers are at the forefront of learning how living resources can be developed in a su
59. upplementary grant may be sought to support the trialing refinement of the prototype and specification of the AbManager package APPENDICES A Acknowledgements Contents of manual Use of package Copied from the AbaSim user manual AbaSim order form Flying Fisheries Article for American Fisheries Society Computer Users Section newsletter ee EN ee NSS Warning Unauthorised copying of the AbaSim software or manual is unethical and illegal Published by the South Australian Department of Fisheries GPO Box 1625 SA Australia 5001 First published 1991 Copynght South Australian Department of Fisheries 1991 AbaSim A Graphic Fishery ISBN 0 7308 1899 3 Software patent applied for All rights reserved Acknowledgments John Tonkin a computer artist programmed the computer game We thank for their assistance support and inspiration Abalone divers their families and representatives Garis Alexander Alan Armstrong Janine Baker Kevin Branden Tracy Brothers Barry Burr Merle Cammiss Steven Clarke Rob Day Lesley Fairbairn Ludmilla Filadelfi Shaun Forbes Wesley Ford Ray Hilborn Patrick Hone John Jefferson John Johnson Jan Kirkegaard Neil Klaer Gordon Kuckhahn Rob Lewis Vivienne Mawson Carol Moore John Nowland Mick Olsen Sharon Palmer Russ Reichelt Natalie Schenk Scoresby Shepherd Hosi Stankovic Simon Talbot Richard Tilzey Angelo Tsolos Mike Walker Carl Walters Meryl Willi

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