÷H(Wed Dec 12 10:19:38 2007) From FISHERY MGMT final for posting.vmfe,‘¾UĮ]Č]Čå]Č ”7Læō|™‚ƒ„GHIJKMFˆ‰"ƒ†‡…Lßƒxx €?Ė$ š Y ±€ö€öé[Ģ €ö$  Q §€ö€öOĢ €ö$° i Ē€ö€öÕŖĢ €ö$„ a »€ö€öĢ €ö$€ö|Š  B€ö€öč®|€öo$%ܝĮ€ö€ö9%ü€ö,(ę]'€ö€ö–Ž<€öŸ,/¼€ö€ö| ‡1Ģ€ö€ö| ‡4% €ö€ö |€ö<,<4$€ö€ö |€ö;,D874€ö€öp3|€ö>,K €ö€ö| ‡NC0G€ö€öp|€öW$U˜Ųi€ö€ö$ü€ö$Y ·Ū€ö€öw6ü€ö#$\L€ö€ö| ‡^V9R€?µ›|€?c$il€ö€ö| ‡laIe€ö€ö–@|€öC$xĖ |®«€ö€öļ|€öL$„Ÿež€ö€öÄR|€öH$~[€ö€ö|€ö4$”Nž^€?æ |€?e$žų"Ę€ö€ö“Lü€ö%,¦9õ€ö€ö‹|€ö_$¬Ć “f €ö€öü €ö,¹6 čė €ö€ö$fü €ö$Åń¬€ö€ö¾Q|€öG,ŠhķV€?É„|€?j$ŲNŻī€ö€ön2|€ö=,å]å.€?¼P|ĶĢĢ=F$ń ¼€ö€öh|€öY,ų*ČBńĄ?l}üĶĢL=0$žõ¬É€ö€öaü€ö",%Ņ¹€ö€öP,|€ö:,"p·€ö€ö"e|€öR,¤sB€ö€ö;kü€ö,,%s†€ö€öū|€öO$1¢€ö€ö-h|€öS,:šT <Ķ@ €ö€ö5 |€ö7,@³(€ö€öŚ¬|€ön$F^€ö€ö1"|€ö6$JĀ0€ö€öŲ«|€öm,PčL$€ö€öAl|€öT$V?, YłU$€ö€öu5|€ö@$`\€ö€ö| ‡c.é>€ö€öFn|€öV$hg’€ö€öĒS|€öI${1xń€?·œ|€?d$‡<ƒ'€ö€ö‡|€ö^,Ę/€ö€öL*|€ö9$•Žv'ČB@œE/!|ČB5$›K« €ö€ö |€öP$¬z¶+A€ö€ö“Œ|€ö`$³ö Ž+ā€ö€ö²Kü €ö©$½B ]±€ö€ö£“ü €ö±$Ć0* ÅØŃ'MśD@œE d|śCQ$ɤ‡ AĻ§|?k$Ō³Ū+l€ö€ö°J|€öE$Żē Ņ—€ö€ö=ü €ö„$ę7 Q+fzDcü  @®$ķĀ„€ö€öõ|€öM$üń¤€ö€öC|€öD,żŹG€?Į”|€?f$'.ź€ö€ös4|€ö?,#¼€ö€öŠ:|€öB$$GBü€?Ć¢|€?g$+Rń€ö€öZxü€ö/$7ˆ:|€ö€öˆ9|€öA$C]W4€ö€öƒ†|€ö\,K5Ś9ü€ö€öU.ü€ö!,MRJ€ö€ö›|€öa$Ui\ $@‰Xtb€ö€ö…‡|€ö]$ak9€ö€öŽV|€öJ,j ē9żČBį­ü  @²$r™ĶĢĢ=@@D&|ĶĢĢ=8$zÆ”*€ö€öu|€öZ,„ģR †×€ö€ö„|€ö[,ŒÄĀ8€ö€öł|€öN$˜ÆŲ \ $@‰›į€ö€öÓ©|€öl$„r$?@ACm|?U$«Y €ö€ö©•|€öb$°}ĶĢĢ=@ė\|ĶĢĢ=K$³ÅB€?Å£|€?h$¼į ¦ €ö€ö”Eü €ö,ĘŠJĶĢĢ=€?Vv|ĶĢĢ=X$ÉŪR €?Ē¤|€?i$Ó‹€ö|ŠŲ–€ö|ŠŪłi³€ö€öL€öž,ߢ€ö|ŠäzĀ€ö€ö7$l€ö,ź0Š÷€?¹l€?$÷%‚ā@? ?- lĶĢL=$’R”%€ö€ö’>l€ö, ;—€ö€öŸ‘l€ö,( IW€ö€öY/ü €ö¢,aĻ@€ö€öól€ö$%Ō€ö|Š+Ł€ö|Š/<;'€ö€ö}ü€ö$,5§ēw€ö€öÉTü€ö($:-,B€ö€ö8jü€ö+$BÄųB‹€ö€ö'ü€ö$Il€ö€ö| ‡Kå²€ö€öŽŠü€ö2,Q( S¦ 5„ €ö€ö_| €ö›,W{„ž’ Ÿ[Š Aī°ü€?3$eQY8€ö€öøMü€ö&,rя—ĶĢL>@ķ]üĶĢL=*$u™jįĶĢĢ= @XwüĶĢĢ=.$xŽaB“€ö€öOtü€ö-$³}.€ö€öq~ü€ö1,‹Ā†B„€ö€öF'ü€ö ,æ žJŒ€ö€ö5iü €öw,—‰ ŠU#śC„Fü ČA¦,žĄęPĆGćXüzD)$£łeš™?ŗNüĶĢL='$«“€ö|Š±• +„€ö€öbL€öŒ$¼§Ę+… €ö€öaL€ö‹$Ź¤+Ä€ö€öL€ö€$Ń ?+D€ö€öąWü €öŖ$Ś0 &! €ö€ö}ƒL€ö‘$åĖ,B €ö€öyL€ö$ņ| I U‘–Cćü A³,ūā6.€ö€ö3#L€ö, ń?Ff€ö€öH(L€ö‚$Ip€ö€ö7L€öƒ$ž tÄ ?@@ŃØL?–$!ĀŃ˜ €ö€öKrL€ö$*”¹r €ö€öL€öŠ,6Z†€ö€ö”?L€ö„$D‰¬c €?±™L€?”$LF¤ō€ö€ö’L€ö‡$U,dČ€ö€ö›BL€ö…$bą Ā €ö€ö L€öˆ$p;lä?@@®IL?†$x_ lœ €ö€ö  L€ö‰$ŃŚ± €ö€ö\yL€öŽ,ˆ ń €ö€ö{‚L€ö,ŒT 6t ?Ą?­—LĶĢĢ=’$•© |Ü €?³šL€?•$I .\ €?ƘLĶĢĢ=“$¦Ę ‚ ė€ö€ö™AÜ €ö$µV€ö|Š»“ †L €ö€öŸDü €ö$Āģ Ō³ €ö€ö÷ü €ö$ĶP ü €ö€öŠˆü €ö$Ó# ßÜ €ö€ö`ü €ö$ŲÖ ›Ju o:†8ü ·Ń8$ąA ńž €ö€öd{ü €ö$ēe  pBŒ‰ü €?$ģž€ö|Šńp F/ €ö€öJ)| €ö—$÷Ą V €ö€öźÆ| €ö$ū… O Ą@R-| ĶĢĢ=˜$ "] €ö€ö*g| €ö™$› *g €?ČAMs| €?š$µ =ö €?«–| ĶĢĢ=œ$j= Ū€ö|Šó ^B €?»žü €?}$'ž kJ €ö€öÜUü €öt,. Ü'€ö€öŒ;ü €ös,7 v €?+ü ĶĢL=p$Dč Jü€ö€öbzü €öy,J$ J“ €ö€öÜü €ö,U> •Oė €ö€öN+ü €öq$^Ÿ äJl·Ń8 ×#<åYü ·Ń8u$f3 ŒŽ €@]0ü €ör$nŁ Jš€ö€ö…ü €ö{$s 6'€ö€öĶ¦ü €ö~$€M Ņ÷ €ö€öńü €öv$Ž÷ . €ö€ö§”ü €ö|,–Ŗ ņJo: ×##SMOOTH3(normallyretiringfromfleet,expectationsmoothtime)#B#LV2#SMOOTH(cpue*sellingpriceoffish,RECENTPASTINCOMESMOOTHTIME)#2#SMOOTHI(catchC,CATCHFORPRICESMOOTHTIME,catchC)#2#SMOOTHI(cpueratio,SHORTTERMCPUESMOOTHTIME,1)#2#SMOOTHI(cpueratio,CPUERATIOAVERAGINGTIME,1)#&#SMOOTH(catchC,SHORTTERMSMOOTHTIME)#&#SMOOTH(catchC,LONGTERMSMOOTHTIME)#".FISHERY MGMT final for posting\”7Læ ‡”7LæXXōU¼Ģ¼ ¼ LĢlLĢĢL \$¼L' Ģ+¼ĢL/¼Ģ 4LĢ 9\Ģ>LĢBlĢFLĢ JLĢĢ O ”7Læō”7Læųųdœ | l | l <  ģüģŒĢ ¼ < , ¼|Ü|  |œü¬ Ģ ü Ģ ü|l\ŒĢ œ |œ\ ÜŒ œ ¼ Ģü¬ ģ Ü ģ ¬ ĢœŒ<ܬĢ\ģ\ģœ|, | ,Ü ¬< \ < ¬, L <|œ¼œl<, ܬģüü< , ¼Œ lŒÜ¼ \¬Ģ<Œ\\| œ,¼|Œüܬ, |ģ |ܬ ¬ Ü Ģ|¬|\ ¼,ܬ|, ¬| ¬<ģ , \ LÜ\    üģ\ \|¬L ÜĢ<¬ŒĢü¬œ\ |œ <ü|œ¬œüœ <<Œ\,ÜܼL¼L ģœ <œ | l L ܬ¬ Œ Ü , Ü ģœ ģ,¬\<Ģ¬ ¬ģ , œ |ll œ¼ ¬¬ü, ܼ\Œ\¼ ¬üŒÜ  ¬ü \ LÜ, ģœ œ œ, ¬ |Ü| ģ ¼|¬Ü¬Ll ¬Üģœœ ģģ Ü L œ <l| ¬ÜŒ l œĢ¬rNO’’€’’’’’ UTimes New RomanMdĄĄĄTITLE PAGEZPQ’’€’’’’’€@ UTimes New Roman dĄĄĄGetting StarteddRS’’’’’’’’’ UTimes New RomandĄĄĄModeling ConventionsZTU’’’’’’’’ UTimes New RomanvĄĄĄMODEL: Fish PopulationQVW’’’’’’’’’ UTimes New Roman.dĄĄĄMODEL: Feedback effects on additionsXY’’’’’’’’’ UTimes New Roman8dĄĄĄMODEL OPTION: Spawning season?Z[’’’’’’’’’ UTimes New RomandĄĄĄMODEL OPTION: constant recruitment?\]’’’’’’’’’ UTimes New Roman[dĄĄĄMODEL: Units of Fishing GearK^_’’’’’’’’’ UTimes New RomandĄĄĄMODEL: capacity utilizationd`a’’’’’’’’’ UTimes New RomanKdĄĄĄMODEL: Prices, income and desired cpueUbc’’’’’’’’’ UTimes New Roman8dĄĄĄMODEL: gear efficiencyZde’’’’’’’’’ UTimes New RomanCdĄĄĄMODEL: fishing effect on ecosystemRfg’’’’’’’’’ UTimes New Roman\dĄĄĄMODEL: Management RoleQhi’’’’’’’’’ UTimes New Roman"dĄĄĄMODEL: Political Willdjk’’’’’’’’’ UTimes New Roman)dĄĄĄMODEL: mean age of biomass[lm’’’’’’’’’ UTimes New RomandĄĄĄMODEL: recruitment fractioneno’’’’’’’’’ UTimes New RomanAdĄĄĄOUTPUT + MAIN CONTROLSZpq’’’’’’’’’ UTimes New RomandĄĄĄOUTPUT Managementdrs’’’’’’’’’ UTimes New Roman"dĄĄĄOUTPUT Fishing Unitsdtu’’’’’’’’’ UTimes New RomandĄĄĄOUTPUT: effect of pricesdvw’’’’’’’’’ UTimes New RomandĄĄĄOUTPUT: Recruitment xy’’’’’’’’’ UTimes New RomandĄĄĄOUTPUT: Mean Biomass Agedz{’’’’’’’’’ UTimes New RomandĄĄĄOUTPUT: CPUE + Catch vs Biomassd|}’’’’’’’’’ UTimes New RomandĄĄĄOUTPUT: Gear Efficiency~’’’’’’’’’ UTimes New RomandĄĄĄOUTPUT: Gear, Environmental effect of d€’’’’’’’’’ UTimes New Roman,dĄĄĄMODEL: noise componentd %T| Ķäų=P‡œ¶ų@Qbq„–©¹Źä€˜¶ćł;q©ÄöZ„ ōeq}“®ŗĘŅŽźöJVjy…Ž—©²¾ŹÖāīś@_H”7Læ” ” ō…nj tÖį„’Ą€ To use navigation buttons: First lock sketch - icon at upper leftŗø mœ&„’Ą’’€@A. The fish population portion of this model is based on the "Schaefer" biomass dynamic model and models the population in terms of biomass. ž™ t÷Ā,„’The number of fishing gear units entering the fishery is determined by the recent catch per unit effort (cpue) from the fishery.Ž‰ '¤)„’1) Optional feedback from biomass to additions so that the additions fraction can decrease as biomass increases,²® —“.„’ 2) Optional partitioning of additions into additions due to growth, and additions due to (possibly delayed) addition of new fish (i.e. recruitment).ZV äh"„’3) Optional addition of random "pink noise" to recruitment.NL LÆĮ„’€@C: Entry and exit of fishing units.vs Ƴˆ"„’Gear efficiency can, optionally, be increased as cpue drops below the acceptable level. š˜ C‰£.’There is also an option to allow for adverse effects of fishing on the ability of the ecosystem to support the fish population.JG Q ·„’€@F. Management of the fishery ŚÕ ŅP ',„’Management attempts to adjust fishing effort up or down depending on the relative stock size. Management attempts to keep the stock size at 50 percent (default) of the virgin stock size.RO w® ź„’€@G. Lobbying by fishers can also occur.fa ŌN 0„’€@H. Political desire for better management can also vary. ó _/„’Relative strength of management views will vary based on lobbying by fishers. If difference between industry's desired rate and management adjustments is high then lobbying will be stronger and will weaken management's suggestions.–‘ Ō}  „’The political mandate for management is stronger when current catches are low compared to recent historical catch levels†‚ äh~(„,’’’ArialA Basis for Understanding Fishery Management ComplexitiesB@ h;„’Ą’’ Fish Population BiomassB> ÆiC „’Ą’’ Units of Fishing Gear:8 <"„’ Ą’’ Management RoleJG µF"„’Ą’’ Strength of Management MandateFA `? „’ Ą’’ Changing Gear EfficiencyJG ·`F!„’ Ą’’ Effect of Fishing on Ecosystem>< m¤„’’Ą Output and ControlsB= réi „’’Ą€ Modeling conventionsfd Eō„(’Comic Sans MSThis Version: October 2007źč ]{Į„’Recruitment additions to the population biomass can optionally be formulated as a Beverton and Holt type recruitment function in which the asymtote and steepness of the lefthand side of the curve can be set.‚} fŁĀ4„’Growth additions to the population biomass can, optionally, be changed from the Shaefer model default (growth directly proportional to stock biomass) to a function that allows a lower growth rate as biomass increases. A second alternative is the use of a Beverton-Holt type relationship whereby growth additions approach an asymptote as biomass increases.^Z ā°x"„’A background gear efficiency improvement can also be implemented.vs dš†"„’Use of existing fishing capacity can, optionally, be influenced by catch per unit effort.²® Œüō&„’Entrance of new, and use of existing, fishing gear is determined by catch per unit effort (cpue) compared to an "acceptable catch per unit effort". VQ nnė„’€@D. Changes in efficiency of fishing gearRO e.ß„’€@E. Effects of fishing on the ecosystem²­ Y¼š.„’The initial value of fishing gear efficiency is set by the user. This is equal to the fraction of the biomass caught by a single fishing gear unit.ÖÓ ™?•„’Additions flowing into a standard Schaefer modeled stock are a constant fraction of the existing biomass already in the stock. There are several reasons why this may not be appropriate.vr ¢‚"’This is formulated as an effect per veesel per year on K the ecosystem carrying capacity.fc ą}"’It can be viewed as, for example, the effects of trawls on bottom habitat.jf ĶI °#„’This is done by adjusting the number of vessels that can enter the fishery. ĘĮ ¼^((„’Acceptable catch per unit will decline as inome levels decline. This will, for example, lower the threshold cpue at which vessels will enter or remain in the fishery.>: °;„’ Ą’’ Prices and IncomeB@ ±“;„’ Ą’’ Use of Fishing Capacity  ż›vA„(’ArialThe purpose of this model is to provide a thinking tool for those who are interested in the management of fisheries and the factors that make management of even a simple fishery complicated.¦” õż9„ ’ ArialAs currently written, the model assumes some understanding of fishery management issues.nj ĢOf„’Following is a brief description of various aspects of the model.NI ”ņŪ0„’Keep in mind that a biomass dynamic model is NOT usually used to model fish numbers. It is used to model biomass. As normally used, a single inflow of additions to the stock combines both 1) growth of fish in the stock and 2) additions due to to the addition of young fish, often called "recruitment." zv ;§Æ„’€@B. Acceptable (minimum) Catch per Unit Effort (cpue), income, and fish pricesFB oIŗ0„’The possibility of using seasonal recruitment has been added. That is, rather than entering the fishery continuously, new fish biomass can enter during a restricted part of the year. This modification has been done in such a way as to maintain the basic functionality of a biomass dynamic model..) \—ƒ’Ą’’ .) aE€’Ą’’ VQ ŽHź„’Fish prices are influenced by the amount of fish caught.jh  ōą!„’Fish price and cpue determine income per unit which influences acceptable cpue..) œņ€’ Ą’’ .) iī€’Ą’’ .) „°€’ Ą’’ .)  z€’ Ą’’ .) —O €’ Ą’’ .) Ut €’Ą’’ .) ³ó €’ Ą’’  q9«1„’ This model was developed with Vensim Professional. It can also be used with the free Vensim model reader and with the free Vensim PLE. If using PLE the clickable links will not work. In that case use the navigation tool at the lower left..) ¤Öƒ’Ą’’ NL *L‡’ click to see this part of the model:7 qĖj„’’Ą To Get Started.) ”˜ƒ’’Ą " <;@ ’’’’ " </@O’’’’ FB éF‡’ click to see this output " A>@µÕ’’’’ .) Üņƒ’’Ą .) –ģƒ’’Ą .) ć±ƒ’’Ą .) Ū{ƒ’ ’Ą .) Ģē Ŗƒ’’Ą .) Sģ€’ Ą’’ b] —É„’Because of this the following options were added to the basic model:²Æ ‘ƒE„’The most important of these is the fact that, in the standard model, the mean age of biomass at equilibrium does not change as fishing effort changes.zx ÷¾š$„(’ArialRichard G. Dudley richard.dudley@attglobal.net–” B!„’See: Dudley, R. G. 2007. A Basis for Understanding Fishery Management Dynamics. System Dynamics Review. 23(4) (winter 2007)4“ (8If~”¤¹×H”7Læłłōč:7 æ—< ’€@ First Test Run>; (‰Y’Go to the Output and Controls page>< [†„’’Ą Output and ControlsB= 3c4!„’’€€€RETURN to Title Pagero S„’Click on the synthesim icon at the top center of the page (the running man with lines)^Y -X„’Change the slider under UNDERLYING ACCEPTABLE CPUE to 30 t/year.VQ ¶Ēõ„’Type any name for a new model run in the white box above>< kāŗ„’Move any sliders -- for example....RN ¾”„’See Help\Vensim Manuals\Model Reader Notes ..... etc.vq U7Ö„’View alternate outputs / controls with clickable links or using navigation at lower leftB= ‰f”„’Click the stop icon to stop the run.<ų :`pŠœ“ĘŻ*;KYt~ˆ”¦ČZk…ŗūH”7Læ,,ōAB= s: „’Ą’’ Standard Conventions~z ”Ź!„’Stocks (also called state variables or levels) are in boxes with the Initial Letters Capitalized –“ x(!„’Rates or flows represent a change of the associated stock with respect to time, and are shown by pipes, arrows, and valves>< ūŠž„’Stocks can only be changed by flowsfb Ž·+„’All other model components have no associated shape and are in lowercase.FD .qŃ„’Model constants are (usually) all UPPERCASE^Z K­0„’Arrows connect one model component to another that it influences.FB ,5+„’Ą’’ Other "Conventions" Used ZX 4’Õ„’’ Lookup functions are in red and start with "LK"–“ DT „’A "ghost" variable is indicated within < > and is a duplication of a model component which appears elsewhere in the model.š˜ 7į&„’Smooth and delay functions are placed in a colored box without a border (indicating that they are actually proxies for stocks).B? ÜE„’Ą’’ Model: Fish Population>; “Ü@„’ Ą’’ Model: Management 63 ™Ū4!„’’€€€Title Pageje F©ā„’’Ą€ To use these buttons: First lock sketch - icon at upper left&! –ł- ‡’number a&! šb.‡’number b.+ ]4q‡’number a- number b" +×÷€Ą " - ę_’€ † Ež„’Although all model components have associated equations, labels on arrows give the diagram more meaning.śõ =rö;„’Herein a + sign signifies that a change in the first component will change the second component in the same direction... all else being equal. A minus sign - signifies that the change will be in the opposite direction.JH +n-B„’Navigation buttons have been added at the upper left or on the left side of the sketch. These allow navigation among views both when viewing and running the model. Make sure the lock icon (upper left) is selected. Alternatively one can use the software's navigation selections bar at the lower left.B? TŽY„’’Ą Output & Control: Mainfc æP…)„’’  Orange Boxes are clickable links to Output / Control pages^Y ŠQ].„’Ą’’ Blue boxes are clickable links to model diagramsro ÅÓ(„€Ą’€Ą’ Blue edged boxes are clickable links leading to associated model views ,` P„(’ArialTo use clickable links in Vensim the sketch must be locked using the lock icon in the upper left. These links will not work in Vensim PLE. Lock is automatic in Vensim Model Reader Š… ,ī#„’Ą’Ą Boxes a pale green background provide additional information pertaining to the current view.Š… CŽ&„’Navigation among views is also possible by using the page up and page down buttons on the computer keyboard.¤+ *<N^p„–ŸØÆøĮČĻÖßčļöż *1:ENW^it}ˆ“š£¬µ¼ÅĪÕąėō’"+2=HOXajszƒ‰”¦ÆŗĆÓäņ#4F_js|…Žœ„°¹ÄĶÓŁäķų$4EU\bhsy„Š‘œ§²ø¾H”7Læ÷÷ōÄB@ ^a'„ĄĄĄĄ to recruitment fraction>9 īcm-‡ĄĄĄĄ effect on growthFA ŖVvF‡ĄĄĄĄ to effect on recruitmentFD M^5‡ ĄĄĄĄ to changing gear efficiency>; UO#„ĄĄ’ĄĄĄto noise componentFA 9JFU‡ĄĄĄĄ to units of fishing gearNK L%r=„ ĄĄ’ĄĄĄ to effect of fishing on ecosystem*( |Vx=+ƒ’’€€€  0z ’" Ļ|’ "  dD|’  0” ’"  Gš’ " d Ęš’€€  0’š" <’Æ ’ 0ŒT ’" DR’ " d ĘR’€€  0R" œf ’ œ€|" ,€š.(ƒ’" !+3½€€€ " +­Ó’€€ " +¬+’€€ *( l M:ƒ  ģuˆP,ƒ" +Qš’ *( Üž, " +’ "  @^ä’  \™Ņ/*( ==’’€ *( œnD(ƒ " #"@s8€ *( ,4=#*( |S; ’€€€€€€  V )" '+Ūė’ " '+@"Ć’ " "+|€  ,kŽM" +'+>d’ " + @%’  üĆ£8 *( ü:!ƒ@€ *( X:+‚’€€€€€€ " 0.+Q“Ą€Ą *( \„+  ’€€€€€€" .+?ō€ " G!+Ōč€ 2@_**( HD.‚’€€€€€€ " 6-@±Ś’€€€  ¬”¶F*( ¬ ŃL’€€€€€€ *( ,÷<L’€€€€€€  <ź‹D" 9; @…½’’ " :; @»×’’ " 8+ć{€ " 8!+Ŗ6’  ÜŪø9(ƒ" !@@CŁ€ &@@®ž*( 6]:’€€€€€€ " C/@Š‡€ " C.@“5€ " /@»€ *( sŖƒ’€€ " G/@E€ >9 Ģž<„’’Ą€€Output: ControlsB? Š?!„’Ą’’Model: Fish Population63 ĻV>„’’€€€Title Page>: Ģz:„’ Ą’’€€Model: Management>< ÖĖF„’Ą’’€€Model: Fishing GearB> Ī»<"„’Ą’’ Model: Political WillB? ÖF„’ Ą’’ Model: gear efficiencyFC ÕAD„’ Ą’’ Model: effect on ecosystemb` ¢#"„<’Ą’Century GothicFish Population Biomass*( ¬¬Jd"@ " R8@³E’ " ;@ Ć’’’’ " @†_’ " @W ’  62 i6I6‡ĄĄĄĄ spawning " @W@wˆ@ b *( ¼a2(’€€€€€€ " Y"@eĪ@ b *( ¬č^^’€€€€€€ " [+@€"’€ %@9G@"@ģū*( Œ³jQ’€€€€€€ " _@ @ ­ĄĄĄ *( Œ‰T!’€€€€€€ " a@ @įlĄĄĄ FD ¢2™]„ĄĄĄĄ constant recruitment optionB> JŒ7!‡’Ą’’ Feedback on additions>9 ±Œ.!‡’Ą’’ Spawning Season?B> Œ7"„Ą’’ constant recruitment?>9 hŒ% „’Ą’’ Mean Biomass Age _Z’h!@…hh'@“H*( ę\Z’€€€€€€ k;@ēś*( |ž©a ‚’€€€€€€ m'@éš ū7*( œC+ ’€€€€€€ *( <2w& ’€€€€€€ *( ,;™2 ’€€€€€€ ro@lŹpo@Œ5qo@¢žÄö ->L\l~”²¹ÄĖŌŻčńü$/:@F`ipw‚–œ¢«±ŗŁž  H”7Læō)NK ‡°r=„ ĄĄ’ĄĄĄ to effect of fishing on ecosystem>9 fķ<„’’Ą€€Output: ControlsB? i{?!„’Ą’’Model: Fish Population63 _34!„’’€€€Title Page>: fi:„’ Ą’’€€Model: Management>< oŗF„’Ą’’€€Model: Fishing GearFB g©<"„’Ą’’ Model: Management MandateB? ońF„’ Ą’’ Model: gear efficiencyFC n/D„’ Ą’’ Model: effect on ecosystemB> Ś{.!‡’’’ Feedback on additions ¼é³ ƒ*( ¬#Œd"@  Ģžė ’"  @v×’’’’ "  @s³’’’’ *( |Č<’€€€€€€ "  @Ó’ *( ,,8HHƒ’ĄĄĄ€@"  @AĻ’’’’ *( ‰®R’€€€€€€ *( <9kN     " + |j’’ *( Ģ·mƒ    *( ģQģU"’€€€€€€ @©Ÿ @÷fa ņŹX1‡’ĄĄĄĄ to population : growth/recruitment additions to biomass"  @f ’  Śŗ'  ģ„”' *( ÜĖX    *( ü$<<ƒ’ĄĄĄ€@"  @ß¾’’’’ @ ±@cž" @§J’  @!" @u ’  zw Ÿ. „<’Ą’ArialEffects of biomass on Growth and 'Recruitment'’ œcl„,’Ą’Arial(recruitment = biomass of young fish entering the fished population)*( ¼5==ƒ’ĄĄĄ€@*( ¬EXƒ    *@>s*@°š" )*@¾’’’’ œ (.9?O`n~Ž ±ĆŌäšž &-4:@GRX^doz€‡“ž¤®ĻÖÜāčļųž H”7Læóóō  ܏3ƒ ,Ļˆ8ƒ@}*( Ģ¦ūMƒ€@ @ųĪ*( ,R# ’€€€€€€ 1@“ų>9 !<„’’Ą€€Output: ControlsB? $Ŗ?!„’Ą’’Model: Fish Population63 %w?„’’€€€Title Page>: !˜:„’ Ą’’€€Model: Management>< *éF„’Ą’’€€Model: Fishing GearFB #Õ<"„’Ą’’ Model: Management MandateB? * F„’ Ą’’ Model: gear efficiencyFC )^D„’ Ą’’ Model: effect on ecosystemB> “«.!‡’’’ Feedback on additions>9 ń¬.!‡’’’ Spawning Season?.* ¼ īŗؼ0,Spawning_period63 •ND„ĄĄĄĄ main model ¼ „:  \1ŚM8ƒ 07Ł ’Łd„Ł 0ÓŁ" ģÓ“7(ƒ’ 05Ł ’¹Łd`Ł 0ˆŁ"*( ܈ŖD'(‚’€€€€€€ @e‡@|@Ö5*( |MQ<’€€€€€€ *( lWžA’€€€€€€ @!Q ¼Ź°P’&@M—&N×*( Ģ* XXƒ’ĄĄĄ€@)@‚\&# Z ķ“¼444,,Graph‚~ N[g„<’Ą’’’ArialThis page for setting seasonal spawning -- if desired l W0-&@°#@/$@7ŗ Lō< 1@ ß-1@bm*( 1(Z’€€€€€€ 4@1*( |CĀL8‚’€€€€€€ 6@]…Dņ Anu|‡’˜£©“ŗĄĖŃł/@N^n€‘£“ÄÕąęH”7Læō ŽÜ ŪĢC„Ą’Ą Some recent research has indicated that above some minimum stock size, the number of recruits produced is effected primarily by the environment and not by the spawning stock size.²® JĢ/„Ą’Ą Consequentially the option is presented here to allow additions due to recruitment to be a constant affected only by a noise input.  œŹ(Y Œ“K*( ŒĒßMMƒĄĄĄ *( oq!’€€€€€€ @ŌĮ*( |Śr~ƒ€ @iĘ*( ¬eI’€€€€€€  @Š@Q}*( |ø :’€€€€€€  @ætžœ „Ģ3„’Ą’Ą Even with this scenario the currently selected stock recruit relationship is in effect below the cutoff stock size.–” [Ś„<’Ą’ArialOptional Selection of Constant Recruitment above a Selected Population Size>9 Ą7<„’’Ą€€Output: ControlsB? ÄĘ?!„’Ą’’Model: Fish Population63 ¹~4!„’’€€€Title Page>: Ą³:„’ Ą’’€€Model: Management>< ŹF„’Ą’’€€Model: Fishing GearFB Āō<"„’Ą’’ Model: Management MandateB? Ź;F„’ Ą’’ Model: gear efficiencyFC ÉzD„’ Ą’’ Model: effect on ecosystemB> >Ę7!‡’Ą’’ Feedback on additions>9 „Ę.!‡’Ą’’ Spawning Season?B> Ę7"„Ą’’ constant recruitment?*( ŪvZ’€€€€€€ @=ŗ’ Ž=.„’Ą’Ą Note that it is most sensible to use this option when also using random fluctuations in recruitment. *<L_js~‰”š §²½ĆÉŠŪäļś  +6<ENY`iry„‹”›¤ÆµĄĘĻŚćźóž!1BP`p’¤ÄĻŚįēķųž $*;Pi}„š”Ŗ°¹ĀČH”7LæųųōĪB? œvD3„ ĄĄĄĄ price and desired cpue>; ­ē^7‡ ĄĄ’ĄĄĄ to management viewFA ³mZ8‡ ĄĄ’ĄĄĄ changing gear efficiency>; Ķk^8‡ĄĄĄĄ to Fish PopulationJE “P*„ ĄĄĄĄ Fishing Capacity Utilization*( ü F4ƒ’’€’’€ " 1- Ģ„’*( Œ c“Tƒ ’ *( ¼xņM8ƒ’’€ *( 0.ā ’  ėć d5ć 0¬ć"*( L ¬J(’@€ *( 0ją ’  ÷įd–į 0¾į"*( < ¾łB(’@€ "  $+ @/O€@€*( ģ×ĘP"ƒ’’€@€ *( ¬ Uƒ@€ " !- ZŠ’’’’"  !+ s€€@€*( LäMƒ’’€@€ " Q+ ©Ū€@€*( L’ś;@€ *( Ģ®p7ƒ@€ I@J," @Ūo’ " + Af€@€*( ¼ S Bƒ     | H ƒ" !+ A˜Ŗ€€" ! +£Y€Ą  bŁ5ƒ*( |ØćI ‚’€€€€€€  Œ„<+ƒ" %+%’Ą€Ą€€€  Tō*’" &+Ó€ *(  Óå0ƒ *@\å*( 5Ś*#ƒ ,@ö." + +>€*( l ×½V ’ " /1@=’  \ •{G*ƒ" 1+ q>€’’*( |½2’€€€€€€ 3$@Ƥ*( üŽj! ’€€€€€€ " 5+ -s€" $- R)€>9 2$<„’’Ą€€Output: ControlsB? 5®?!„’Ą’’Model: Fish Population63 +f4!„’’€€€Title Page>: 2›:„’ Ą’’€€Model: Management>< <ģF„’Ą’’€€Model: Fishing GearB> 3Ü<"„’Ą’’ Model: Political WillB? <$F„’ Ą’’ Model: gear efficiencyFC ;bD„’ Ą’’ Model: effect on ecosystem~| ą[° „<’Ą’ArialFlow of Fishing Vessels Into and Out of the Fishery*( L £ę‚’€€€€€€ *( < Ēw_‚’€€€€€€  , «‚RƒAC@BC@%M*( \šEƒ FQ@`å63 Ņī„’ Ą’’ Cap. util. <äžGƒI@½Ķ*( |™q8(‚’€€€€€€ KI@śSB= ±ė)!„’ Ą’’ price & desired cpueRN •ZRR„’ĄĄĄ    balanced fishery - vessel replacementb_ ’Æ``„’ĄĄĄĄĄĄ more vessels decrease cpue decreasing entering vesselsNK m(II„’ĄĄĄĄĄĄ very low cpue increases retirments <‘–Mƒ*( ĢWŲWƒ ’ *( üŹ™‚‚’€€€€€€  Üė/Hƒ" T+B退 RT@Āń" Q&+S€@ " T&+|›€€ ST@õź @Z° ÷ *17>GPYdju~ŽŸ­½Ķßš 1@ITZsH”7Læłłō„*( ĢEź7 ’€€€€€€ *( Ü4 I ’ *( œtC  |āŖ,@O ¬Ō‘_" @>;’ "  +]§’’’’ " +X’’’’ *( ŒzNNƒĄĄĄ€@ @>*( ¼(M’’€ "  +&Ł’’’’ >9 ÉÅ<„’’Ą€€Output: ControlsB? ĢT?!„’Ą’’Model: Fish Population63 Ā 4!„’’€€€Title Page>: ÉA:„’ Ą’’€€Model: Management>< ӒF„’Ą’’€€Model: Fishing GearFB Ź‚<"„’Ą’’ Model: Management MandateB? ÓÉF„’ Ą’’ Model: gear efficiencyFC ŅD„’ Ą’’ Model: effect on ecosystemvt (r˜„’Ą’Proportion of Currently Permitted Fishing Gear that is Actually Being Used B= T’4„’Ą’’ Capacity utilization:8 KķO0‡ĄĄĄĄ to fishing gear" -!+’’’’ *( Ź¼@$ƒ’  @{b] "3RR„’ĄĄĄĄĄĄ - decreasing cpue will decrease capacity utilizationB= Q’3„’ Ą’’ price & desired cpueĢų #*5@KV]fou~‡’›¦¬³¾ÄŌåó%6HVenwˆœ§²ø¾ÉĻęķóü &/Z…—¦­“ŗĄĘĢŅš÷!,28H”7Læööō>:8 ·Y]‡ĄĄĄĄ fish population*( œ¶2‚’€€€€€€  ¬Vm."ƒ*( ¼<1ƒ *( œuŌVƒ’ *( Œ@‚< ƒ’’€ *( œ+€A+ƒ’’€  l+±L" +=ļ’’’’ " -¶€’’’’ @~A" @x’ " -źń’’’’ *( ,ƒÅQ " +©Ē’’’’ *( \Ź :ƒ @ņĄ |ŸB5 ƒ*( Œ¦5FFƒĄĄĄ€€ @I>9 žć<„’’Ą€€Output: ControlsB? ¢\?!„’Ą’’Model: Fish Population63 £$@„’’€€€Title Page>: žW:„’ Ą’’€€Model: Management>< ØŸF„’Ą’’€€Model: Fishing GearFB Ÿœ<"„’Ą’’ Model: Management MandateB? ØŁF„’ Ą’’ Model: gear efficiencyFC §D„’ Ą’’ Model: effect on ecosystem63 >Ÿ„’ Ą’’ Cap. util.:5 b`4‡ĄĄĄĄ fishing gear" - R’’’’ " ?Ö“’’’’ B= (Ÿ1!„’ Ą’’ price & desired cpueNK %ī.*„’’Ą Output & Control: Effects of Price*( üµ¶! ’€€€€€€ *( ģBEƒ’’€ #$@å$@ęž*( ,vJ '$@KČZX sZKK„’ĄĄĄĄĄĄ lower income will lower minimum acceptable cpue ü€%2#ƒ#*@¤Ń" *+uø’’’’  œIæ.&ƒ" *-+@st’’’’ $-@ć©" -+ ’’’’ *( lS¢N!ƒ’ " 1@Č²’ Ŗ¦ ·»®.„’Ą’Ą Note: There seem to be two issues here. Lower incomes will neccessitate continuing to fish at lower cpue to make ends meet. Ŗ„ øÆ6„’Ą’Ą But lower prices would require a higher catch to compensate thus raising the minimum acceptable cpue to stay in the fishery.*( ¹‘. ƒ’  0/7 ’9,æ" 96D,’’’’  0,Ł! ¬nŁ9(’9@ģó:@ģé:@}‘5:@¬ŗ@Mvr ū,˜"„<’Ą’ArialRelationship of Catch, Prices, and Income ģ 9(ƒ*( üD’€€€€€€ BA@™ ÜžŹC(ƒ ŒŌ9 *( ¬ńÉE’€€€€€€ *( œś'+ ’€€€€€€ ED@tŌFE@NįGE@°.Ųõ *1<GNW`gnw‚‹’™¢«²»ĘĻÖßčńų '0;DOXcŁ/=M]n‘œ„°¶¼H”7Læō7FC ż˜b-‡ĄĄ’ĄĄĄto numbers of fishing gear:6 ˜Uƒ4‡ĄĄ’ĄĄĄto main model ˜[<*( Ģ š#I'ƒ’’€ *( \ ŌhH+’’  0s ’"  FrĄ€Ą "  d¼rĄ€Ą  0ųr" l ų—G(’" + `cĄ€Ą *( ¬ ńmY#ƒ "  -yĮĄ€Ą  Ü ¬¶?" L ;9" +@p`Ą€Ą " -DŗĄ€Ą  , ŅKGƒ" -töĄ€Ą *( ¼ „ü: ’" @Ą€Ą   ^ÖCƒ" +æ|Ą€Ą" +ā Ą€Ą " +ŃķĄ€Ą  œ µ? " +–”Ą€Ą "  +ŲOĄ€Ą" -9ČĄ€Ą" +@i6Ą€Ą *( ģ MH " +@ŻwĄ€Ą *( Œ ż Lƒ " !@XšĄ€Ą *( Ģüœ7 ’€€€€€€ " #+cyĄ€Ą *( | ū°9 €€€ ²° S ‰7‡,’Ą’Ą ArialNot included: Costs of implemented improvements and the effect of these costs on acceptable cpue ratio."  ųĄŖe„’Ą’Ą As cpue ratio drops fishers tend to implement strategies that improve the effectiveness of their gear. These improvements tend to be absorbed into what becomes normal gear efficiency. There is also the possibility of a baseline improvement rate.®Ŗ Špz'„<’Ą’ArialImprovements to Fishing Gear Efficiency are Dependent on Recent Changes in Catch per Fishing Unit" @ŌGĄ€Ą >9 „d<„’’Ą€€Output: ControlsB? ‡ņ?!„’Ą’’Model: Fish Population63 }Ŗ4!„’’€€€Title Page>: „ß:„’ Ą’’€€Model: Management>< Ž0F„’Ą’’€€Model: Fishing GearB> … <"„’Ą’’ Model: Political WillB? ŽhF„’ Ą’’ Model: gear efficiencyFC Œ¦D„’ Ą’’ Model: effect on ecosystem*( < ējƒ " 2+$Ż’’’’ *( Ą~==ƒĄĄĄ€@ 4@¦%@ńźē LB²˜„’Ą’Ą Two types of improvements to fishing gear and are indicated here. One is an improvement that takes place when catch per-unit effort drops below acceptable levels and fishermen attempt to raise the catch per-unit effort by improving fishing techniques. Some of this improvement will be retained as standard fishing practice. The second type of improvement could be a constant background improvement in fishing techniques regardless of the cpue.€ %,28?FMS\cju|…Ž—¢«¶æČ &18AJU^†Ÿ°¾ĪŽšs¹biou€‡“ž¤Ŗ°ĄŃßļ’!H”7Læō3B> gĻt:‡ĄĄ’ĄĄĄ go to Fish Population*( üĮƒ_3’’  0_ ’_`dŻ` 0Ŗ` " , Ŗ:/( 0,© ’ ņŖ"  d-kŖ’’’’  0¼Ŗ" < ¼Ī$(’*( ¹i?)ƒ  \ BĖH" -žį’’’’ "  +G{’’’’ " +‰ņ’’’’ *( l R. " -ę’’’’ *( L ÕOƒ€@ "  +=ä’’’’ "  +€Y ’’’’ īé ŗįĆ4„ ’Ą’Ą The ecosystem loss rate is dependent on the number of fishing units. Note that if 1000 units fishing for one year destroy 10 percent of capacity then each unit destroys .0001 of the capacity  jŃX" +h€ FD ©t:‡ĄĄ’ĄĄĄ go to units of fishing gear*(  ##E!ƒ ’  å„<"  @Z’ " - Ęß’’’’ *( “:’€€€€€€ "  +{/€€€€ ž› «;$„<’Ą’ArialFishing activity can decrease the underlying productivity of the fishery ecosystem" @I9€ >9 š=„’’Ą€€Output: ControlsB? '?!„’Ą’’Model: Fish Population63 ń@„’’€€€Title Page>: :„’ Ą’’€€Model: Management>< $fF„’Ą’’€€Model: Fishing GearFB V<"„’Ą’’ Model: Management MandateB? $F„’ Ą’’ Model: gear efficiencyFC #ÜD„’ Ą’’ Model: effect on ecosystem @¼źfd hKļK„’Ą’Ą The underlying "Schaefer model" employs the concept of carrying capacity K and this provides a convenient element in the model where the effects of fishing on the environment can be incorporated. It is well known that certain fishing techniques can alter the underlying capacity of the ecosystem to support fishes. uŲā=„’Ą’Ą Herein the exact nature of that effect is not specified. It is merely implemented in a way whereby each fishing unit causes small fractional damage to the supporting ecosystem in addition to its direct effect on the fish population.†‚ o5ŲZ„’Ą’Ą’ IMPORTANTLY, the affect of ecosystem degradation in this model does not have much effect even when the stock size is large. This is because the role of K is limited to the effect on mortality and becomes greater as the stock size increases. In the case of overfishing, when the stock size is small, a decreased K has only a very limited effect oÖŲB„’Ą’Ą’€ This would indicate that there needs to be some other mechanism in the model whereby ecosystem capacity affects the fish stock. This could be a more direct effect, a negative effect, on the growth coefficient as the ecosystem declines. ¬ N+ƒ0 @” 0@c0*( œŪE’  |‚R&ƒ34@‰y04 @’`*( \$<BBƒĄĄĄ€ 74@µ4 @z\0@±>9 Å×<„’’Ą€€Output: ControlsB? Ča?!„’Ą’’Model: Fish Population63 ¾4!„’’€€€Title Page>: ÅN:„’ Ą’’€€Model: Management>< ĻŸF„’Ą’’€€Model: Fishing GearB> ʏ<"„’Ą’’ Model: Political WillB? Ļ×F„’ Ą’’ Model: gear efficiencyFC ĪD„’ Ą’’ Model: effect on ecosystem4 ,=N`p{†–Ÿ¦±¼ÅŠŁäķų  )2;DOXcnw‚‹–ŸŖ³¾ĒŅŁäķų(fqx~…Ž—¢ØÕąėö’#,2=CJS\e—§øĘÖę÷#)6<B¤ĻŚH”7LæūūōąŠ† ļˆ”&„’Ą’Ą Use a value of 1 if managers are aware of, and account for, variations in carrying capacity.B= ÜKJA‡ ĄĄĄĄ to ecosystem effectsB>  ul5„ĄĄ’ĄĄĄ to management mandateFA o§·o‡ĄĄĄĄ to Units of Fishing Gear>; Łü_g‡ĄĄ’ĄĄĄ to Fish Population*( lHKl)ƒ@€ *(  ?N?ƒ’’€@€  0š ’"  Ó€@@€ "  DZ’’’’  0"*( ÜB9(’@€ *( ™ŸN$ƒ@€ "  +-µ€@@€ *( Œ Óļ: ’ "  @ĪI€@ *( ü­Ø<&ƒ@€ "  -DŁ€@@€ *( ģØO@€ " -ƒz€@@€ "  +@OK€@@€ *( \ »'m@€ *( l µ}Tƒ ’ " +€“€ " +ž˜€ " @=~€ " '+Č€*( | !ŹT#ƒ " -žu’’’’ *( Ü °ÓN"ƒ€@ *( |łVDƒ€" 4 @P«Ą€Ą *( ¼Å½H‚’€€€€€€ " !@mī’€€€ *( ģŅ+\"‚’€€€€€€ " +@(ą’ *( Œ”fR’€€€€€€ " %+q‰€@ *( \U1ƒ€" '@hr€€ *( ģ ĄE#‚’€€€€€€  œ yE1#*( ¼ P@ " * +(r€@ ( #@+}€@ " +* @‰ņ’’’’ š˜ oq0,„<’Ą’Century GothicManagement Attempts to Adjust Fishing Gear Numbers to Obtain Desired Stock Sizeöō Ōw¼V„’Ą’Ą Relative strength of management views will vary. If difference between industry's desired rate and management adjustments is high then lobbying will be stronger and will weaken management's suggestions.*( L ‰źAƒ ’  , žea+ƒ12@łŠ œåéZ ƒ" 24@ż’’’’ " 4@e’’’’ *( < ;Z88ƒ ĄĄĄ 72@µŃ²Æ Ņ‡I„’Ą’Ą Note: This ratio if managers are not "aware" of decreases in unfished stock size caused by damage to the ecosystem caused by fishing.*( ÜK8-‚ ’€€€€€€ *( |ÓĶ<’€€€€€€ *( Ģā6^!    " ;<+zŌ’’’’    " :<-÷’’’’    *( Ģ 2@@@ƒĄĄĄ€@  ¬ Ź2" <@+@¢›€@ " @*+× €@ ?@@m-*( ģ yb8‚’€€€€€€ D4@ˆ ¬Nc$ƒ" %F+“€@ " 'F@Õ_€Ą " F2@b¾’’’’ ĘĮ ”×B„’Ą’Ą Can this be added? : Alternate management based on desired catch rate calculated from stock size, desired stock size, units of gear and gear efficiency.>9 ~›E„’’Ą€€Output: ControlsB? x*?!„’Ą’’Model: Fish Population63 xó?„’’€€€Title Page>: ~D„’ Ą’’€€Model: Management>< ~hF„’Ą’’€€Model: Fishing GearB> ~WD!„’Ą’’ Model: Political WillB? ~ŸF„’ Ą’’ Model: gear efficiencyFC }ŽD„’ Ą’’ Model: effect on ecosystem" @>ģ€€ !F@Ÿ2- ">=„’’Ą€€Mgmt@™*@ń-†‚ ~Ųb„’Ą’Ą The management approach modeled here is based strictly on the management's perception of the fish stock in relation to the assumed maximum possible stock size. If the stock is in "good shape" then management will recommend more units of fishing gear. If the stock is in poor shape than management will recommend decreased fishing gear numbers.Ŗ§ !Ł.„’Ą’Ą However, as modeled, managing cannot directly remove fishing units from the fishery but can only limit entry of fishing units.*( ÜH!K’€€€€€€ Z'@˜Ćdś  +6ALW]ciryˆ‘œ„°¶ĘĻŲ&4DTevˆĄH”7LæłłōŚ>; ĮD ĄĄ’ĄĄĄ to fish population ģ j[h"*( œ¶+ ’€€€€€€ *( < ŲŻG’’€ *( L "); *(  cŽD"’’€ *( , ›;  @\€@_ž@7ē" @Ų%€€  °Œg  @C"  @ńd€€ "  @%Ö€€ *( ü ˆ”Mƒ ’ " @–õ’ *( ģ ¾ę??ƒĄĄĄ€€ @Ņ‰>; Zh ĄĄ’ ĄĄ to management view" @+Ņ€€ " @é€€ ²® cU`2„<’Ą’ArialThe Political Will for Management is Dependent on Current Catches Compared to Historical Catch Levels>9 ؆<„’’Ą€€Output: ControlsB? «?!„’Ą’’Model: Fish Population63  Ģ4!„’’€€€Title Page>: Ø:„’ Ą’’€€Model: Management>< ±SF„’Ą’’€€Model: Fishing GearB> ©B<"„’Ą’’ Model: Political WillB? ±ŠF„’ Ą’’ Model: gear efficiencyFC °ČD„’ Ą’’ Model: effect on ecosystemŽŚ œ¦3„ ’Ą’’ This lookup may need to be made more effective..... the effect of low catches compared to large catches in the past may need to be stronger if this effect is to be used (060616)fa NJPP„’ĄĄĄĄĄĄ historically low catches will give management more powertų !,2BSaq“¤¶ĘŃŲŽäėņł’ $/5;AOZ`~„­¾ĻH”7LæłłōÕ Įæ1 *( œ7…+ ’€€€€€€ @†…*( <:Ģ& ’€€€€€€ @~Ū>9 źI<„’’Ą€€Output: ControlsB? ķ×?!„’Ą’’Model: Fish Population63 ć4!„’’€€€Title Page>: źÄ:„’ Ą’’€€Model: Management>< ōF„’Ą’’€€Model: Fishing GearFB ė<"„’Ą’’ Model: Management MandateB? ōMF„’ Ą’’ Model: gear efficiencyFC ņ‹D„’ Ą’’ Model: effect on ecosystem>9 †×% „’Ą’’ Mean Biomass Age*( ģĀķ@*ƒ’’€  0Žą ’PādÕā 0ā" )(ƒ’ 0æē ’ƒād#ā 0Kā" üK,(ƒ’*( ĢŲ1G#ƒ€ @<*( |«§D‚’€€€€€€ @2@©ą@—b62 Z ōR‘!¼0,AGE_of_BIOMASS_Mean_TST*( lÅ4>’€€€€€€ !@Å!vq ÅW„<’Ą’Century GothicCo-Flow to calculate mean age of biomass@˜^¢  '?˜,„’Ą’Ą Remember that "age" refers to age of _biomass_ in the stock (excluding young fish that have not yet entered the stock).B= w4„’Ą’’ Recruitment FractionB= £æ;&‡Ą’€Ą’ recruitment fraction'@)Źˆų &,29Dhou{‘¢°ĄŠāó&7GXH”7LæłłōŖ*( ¼ł=!’ *( Ģ ~T%‚’€€€€€€  <Ŗ¢M)ƒ@+1@Ó LĒW!*( ,”É;;ƒĄĄĄ€ Ž‰ ėqņ)„’Ą’Ą What is the relationship between mean age of biomass and fraction of biomass due to recruitment? ź¦T’ @>Ł @ż @“F>9 —Č<„’’Ą€€Output: ControlsB? ›W?!„’Ą’’Model: Fish Population63 š >„’’€€€Title Page>: —D:„’ Ą’’€€Model: Management>< ”•F„’Ą’’€€Model: Fishing GearFB ™…<"„’Ą’’ Model: Management MandateB? ”ĢF„’ Ą’’ Model: gear efficiencyFC   D„’ Ą’’ Model: effect on ecosystemB> V7!‡’Ą’’ Feedback on additions>9 |V.!‡’Ą’’ Spawning Season?B> ęV7"„Ą’’ constant recruitment?>9 3V% „’Ą’’ Mean Biomass AgeB= Ž”ƒ„Ą’’ recruitment fractionFA ėŪų@„’Ą’Ą For the purposes of this model the relation between the mean age of biomass in the fraction of additions from recruitment is indicated in the lookup function. The analytical relationship between these two values is beyond the scope of this model, but it's an interesting subject.4ų -FQ\gr}ˆ“žøÓń’ *5EXk~¢°»ĘŃŽņAXw—¢­øĪåšū%ALnˆ“£®¹ÄĻźõ&1H”7LæōC*( äXį#€’’Ą€ b^ +C«œ„4Ą’’ Century GothicAdditions from Growthb` >¼˜'„4Ą’Ą Century GothicFishery Characteristics*( ¬ 8†D ’€€€€€€*( ģ <Ée ’€€€€€€*( Ü 9c ’€€€€€€*( < <er ’€€€€€€*( L:<u‚’€€€€€€ *( | 9÷˜‚’€€€€€€ *( ¼ ;²–‚’€€€€€€ *( L =®r‚ ’€€€€€€ fc 9?ŒC„4€Ą’ Century GothicPopulation Characteristicsjg ąčŪB„4’’€ Century GothicRandomizing Reproductive Inputvr WćÆ„4’Ą€ Century GothicAdditions from Reproduction (Recruitment)63 ī [Ā#ą^¼0,CATCH,_BIOMASS,_AND_CPUE*( <-‚ ’€€€€€€ :8 D²_’Ą’Ą See NOTES belowB? Z;„’Ą’’ Model: Fish Population*( ¼H2‚’€€€€€€ >; œ[=„’ Ą’’ Model: Management JE é]X„’’Ą Output & Control: ManagementJH é–V„’’Ą Output & Control: Fishing UnitsJF ›^T„’’Ą Output & Control: RecruitmentB? 5]Y„’’Ą Output & Control: MainJG H–V„’’Ą Output: CPUE, Catch vs Biomass63 .@„’’€€€Title Page*( Ģ Ž¼= ’€€€€€€ *( Ü Ūńœ‚’€€€€€€ *( œšĶ±‚ ’€€€€€€ 2. 11„’’Ą NoiseNJ ›–S„’’Ą Output & Control: Gear EfficiencyRM H_V„’’Ą Output & Control: Environment Effect2. "tRz Ą’ĄNOTES²Æ «E·.’For a standard biomass dynamic (Schaefer) model set "switch to use BH recruitment", "Switch to use ALT growth", and "Switch to use BH growth" to zero.ZX 4„Œ!’To deactivate the fishery set "initial number of units" to zerozv @EŠ"’For recruitment only (no growth component) set "fraction of additions from recruitment" to 1~z ¼µ‘*„’Effects on recruitment are operable only if "fraction of additions from recruitment" is non-zero.*( ,>l‚’€€€€€€ *( l>^z‚’€€€€€€ *( Ģ3G4‚’€€€€€€ VS ¹l"’k determines the asymptote of the stock vs additions curveZW *¶l"’p determines the halfway point of the stock vs additions curve*( ,˜ ·‚’€€€€€€ *( ü+g‚’€€€€€€ *( ģ{§7‚’€€€€€€ *( Ż„7‚’€€€€€€ NK 6—V„’’Ą Output & Control: Effects of Pricenj Ņ2„’’Ą to see additional detail, controls, and notes - click these boxes*( ¼+Ȇ‚’€€€€€€ †ƒ ØÆ®)„’Note that the effect of the ALT growth function requires a non-zero value for "feedbact effect on growth".fa Ż«Ł[„4’Ą€ArialUse Seasonal Recruitment*( ĢčŖ‚’€€€€€€ >9 Š;„’Ą’’ spawning season?*( Ģņo©‚’€€€€€€ *( ,¬ZŸ‚’€€€€€€ *( L¤X2‚’€€€€€€ *( *:«€’    je *ß;;Ē'’Ą’ĄĄ’Ą€ Arial Rounded MT BoldFor testing, try this slider*( ³= Ć’Ą’ĄĄ’Ą , :;@ė#€Ą fb Duˆ„%Ą’ĄĄ’Ą Arialsecondary characteristics*( < H­k ’€€€€€€ *( ģ HYM ’€€€€€€ FA ś_U„’’Ą Output: Mean Biomass Age, '2=HS^it€‘”“ĒŚėž -B[o}H”7Læłłō>; ĀR‹5„Ą’Ą Management Factors63 ä F;ń÷ł¼0,CATCH,_BIOMASS,_AND_CPUE*( ģ æś~‚ ’€€€€€€ *( < ø¢z‚ ’€€€€€€ *( Ü »Kw‚ ’€€€€€€ *( ¼ Į[t‚ ’€€€€€€ *( üĘ¹z‚ ’€€€€€€ *( Ģ ĄV‚ ’€€€€€€ *( | Ģn$‚ ’€€€€€€ .+ . 1Š–§©¼0,Lobbying_on_MgmtB? ¤;„’Ą’’ Model: Fish Population>; ü„=„’ Ą’’ Model: Management JE HŠX„’’Ą Output & Control: ManagementJH HĆV„’’Ą Output & Control: Fishing UnitsJF ū‹T„’’Ą Output & Control: RecruitmentB? ”ŠY„’’Ą Output & Control: MainJG §ĆV„’’Ą Output: CPUE, Catch vs Biomass63 ~[@„’’€€€Title Page2. ‘·„’’Ą NoiseNJ ūĆS„’’Ą Output & Control: Gear EfficiencyRM §ŒV„’’Ą Output & Control: Environment Effectb_ =_„’’Ą to see additional detail and notes - click these boxesNK •ÄV„’’Ą Output & Control: Effects of Price63 ¼Ż[„’ Ą’’ managementFA ZŒU„’’Ą Output: Mean Biomass Age ų &,2@JWhx‹ž±ĀÕćš$/:EP[fq|ž©¶ĒH”7LæłłōŁ*( L ¾\I"‚’€€€€€€ *( < Łó<’€€€€€€  , ĪR@_=@J63 Ō Uæ'3¾¼0,CHANGES_IN_FISHING_UNIT_&$ b O¾˜3Ƽ2236,,Graph20 8 Q¾2¹¼0,PROPOSED_ENTRY_RATES_B? Š";„’Ą’’ Model: Fish Population>; M#=„’ Ą’’ Model: Management JE šX„’’Ą Output & Control: ManagementJH šAV„’’Ą Output & Control: Fishing UnitsJF L T„’’Ą Output & Control: RecruitmentB? č$Y„’’Ą Output & Control: MainJG łAV„’’Ą Output: CPUE, Catch vs Biomass63 Ć÷4„’’€€€Title Page2. ā5„’’Ą NoiseNJ LAS„’’Ą Output & Control: Gear EfficiencyRM ł V„’’Ą Output & Control: Environment Effect*( LEd‚ ’€€€€€€ *( ¬ )Ż²‚ ’€€€€€€ *( ¼ ‰t‚ ’€€€€€€ *( :ƒk‚ ’€€€€€€ *( Ü =ń­‚ ’€€€€€€ *( < /_S‚’€€€€€€ *( \AŁC ’€€€€€€ *( ģ :ęq(‚’€€€€€€ *( Œ"On"’€€€€€€ †‚ Ö^ž)„’ĄĄĄ’’’NOTE Should acceptable cpue be based on recent cpue. What is the effect of doing this??!*( „¾€’ 2. j >.¦£Ž¼0,cpue_ratio_vs_enterB= !Se„’Ą’’ Model: Fishing UnitsFA « U„’’Ą Output: Mean Biomass Agexų *=Pct‡•¢¶Ėßķž ".:SH”7LæłłōeB? Ÿ#;„’Ą’’ Model: Fish Population>; $=„’ Ą’’ Model: Management JE i X„’’Ą Output & Control: ManagementJH iBV„’’Ą Output & Control: Fishing UnitsJF  T„’’Ą Output & Control: RecruitmentB? “ Y„’’Ą Output & Control: MainJG ČBV„’’Ą Output: CPUE, Catch vs Biomass63 ŸŚ@„’’€€€Title Page2. ±7„’’Ą NoiseNJ BS„’’Ą Output & Control: Gear EfficiencyRM Č V„’’Ą Output & Control: Environment EffectNK ¶CV„’’Ą Output & Control: Effects of Price63 j ;‘\<ęœ0,Catch_Effect_on_Price_anB? Ü\[„’ Ą’’ price and desired cpue63 8 Lų<²¼0,Catch_and_Price_over_Tim*( Œ·½Z"’€€€€€€ *( Œ®Tn"’€€€€€€ .) ä ?^=č¼0,Income_vs_cpue.) b K~=Ń¼0,Price_vs_Accepb_ DŪ„’’Ą to see additional detail and notes - click these boxesFA z U„’’Ą Output: Mean Biomass AgeHų  +6ARbuˆ›¬æĶŚīBMXlwŠØ³¾ĻH”7Læłłōį.+ j E6üŽS¼0,BIOM_VS_RECRUITS*( Ü ¹]‚ ’€€€€€€ *( ¼r + ‚’€€€€€€ *( œ¶w}‚ ’€€€€€€ *( Ģ ¼P1  ’€€€€€€ B? ‘J;„’Ą’’ Model: Fish Population>; K=„’ Ą’’ Model: Management JE Z0X„’’Ą Output & Control: ManagementJH ZiV„’’Ą Output & Control: Fishing UnitsJF 1T„’’Ą Output & Control: RecruitmentB? ØLY„’’Ą Output & Control: MainJG ¹iV„’’Ą Output: CPUE, Catch vs Biomass63 „ 4„’’€€€Title Page2. £^„’’Ą NoiseNJ iS„’’Ą Output & Control: Gear EfficiencyRM ¹2V„’’Ą Output & Control: Environment Effect*( Ģ :‚’€€€€€€ *( lžÆA’€€€€€€ ¢Ÿ ¾­­?„’’Ą€ Note that asymtotic level of recruitment is equal to: 0.5 * r * k * Bm*(1+k) * fraction of additions from recruitment*( ,Ń²R’€€€€€€ *( <"ˆ+‚’€€€€€€ NI ĆĻŸ„’Ą’Ą Random Variation in Recruitment?*( ¼Æm$‚’€€€€€€ JG Ä‹ „’Ą’Ą Alternate Recruitment FunctionJF w„’Ą’Ą Use Alternate Growth Function*( ü½ÆA’€€€€€€ *( ģg2 ’€€€€€€ *( "2 ’€€€€€€ B? Čw… „’Ą’Ą Use BH Growth FunctionFA k1U„’’Ą Output: Mean Biomass AgeXų *=Pct‡•§“ČŻźH”7LæłłōųB? Œ‰;„’Ą’’ Model: Fish Population>; Š=„’ Ą’’ Model: Management JE UoX„’’Ą Output & Control: ManagementJH UØV„’’Ą Output & Control: Fishing UnitsJF pT„’’Ą Output & Control: RecruitmentB? £‹Y„’’Ą Output & Control: MainJG “ØV„’’Ą Output: CPUE, Catch vs Biomass63 ~]4„’’€€€Title PageFA hpU„’’Ą Output: Mean Biomass Age2. ž„’’Ą NoiseNJ ØS„’’Ą Output & Control: Gear EfficiencyRM “qV„’’Ą Output & Control: Environment Effect2. * +›V¼0,AGE_of_BIOMASS_Mean62 , /qm¼0,AGE_of_BIOMASS_Mean_TSTüų "->Nat‡˜«¹ĘŚļ5g€‡’›¦H”7Læłłōø64 ä g+?l¼0,BIOMASS_EFFECT_ON_VARIOUS*( ģ åS~ ‚ ’€€€€€€ *( < äĢŠ‚ ’€€€€€€ B? =€;„’Ą’’ Model: Fish Population>; ŗ=„’ Ą’’ Model: Management JE fX„’’Ą Output & Control: ManagementJH ŸV„’’Ą Output & Control: Fishing UnitsJF ¹gT„’’Ą Output & Control: RecruitmentB? U‚Y„’’Ą Output & Control: MainJG fŸV„’’Ą Output: CPUE, Catch vs Biomass63 /U4„’’€€€Title Page2. O”„’’Ą NoiseNJ ¹ŸS„’’Ą Output & Control: Gear EfficiencyRM fhV„’’Ą Output & Control: Environment Effect ꀛa„’Ą’ĄĄ’Ą Note: The 'potential gear improvement fraction' indicates the amount of gear improvement which would be possible if a 100% effort were made. Some of this improvement is implemented if catch rates drop below what is normally acceptable.ĘĮ é(›G„’Ą’Ą The second option 'background gear improvement rate' determines what fraction of the above potential will be implemented regardless of the catch rate. b] ē‹˜„’’Ą Click here to see: Output & Control: Gear Efficiency \ 4**( œA- ’€€€€€€ " @Ā’’’’€€€ *( ąŪv‚ ’€€€€€€ FA hU„’’Ą Output: Mean Biomass Ageüų *=Pct‡•¢¶ĖÖįšū0H”7LæłłōBB? »¦;„’Ą’’ Model: Fish Population>; 8§=„’ Ą’’ Model: Management JE „ŒX„’’Ą Output & Control: ManagementJH „ÅV„’’Ą Output & Control: Fishing UnitsJF 6T„’’Ą Output & Control: RecruitmentB? ŅØY„’’Ą Output & Control: MainJG ćÅV„’’Ą Output: CPUE, Catch vs Biomass63 ®{4„’’€€€Title Page2. Ķŗ„’’Ą NoiseNJ 6ÅS„’’Ą Output & Control: Gear EfficiencyRM ćŽV„’’Ą Output & Control: Environment Effect*( ģ YBL‚ ’€€€€€€ *( < X±S&‚ ’€€€€€€ :6 ä RĪū¼0,BIOMASS_EFFECT_ON_VARIOUS_0*( | X= ’€€€€€€ *( ¬ Z­Q ’€€€€€€ 62 8 Vœś¼0,Fishing_Gear_Efficiency*( céx‚ ’€€€€€€ B? ūÕr„’ Ą’’ Model: Gear EfficiencyFA ™U„’’Ą Output: Mean Biomass AgeŌų *=Pct‡•¢¶ĖÖįėH”7Læłłō*B? I—;„’Ą’’ Model: Fish Population>; ʘ=„’ Ą’’ Model: Management JE }X„’’Ą Output & Control: ManagementJH ¶V„’’Ą Output & Control: Fishing UnitsJF Ä~T„’’Ą Output & Control: RecruitmentB? `™Y„’’Ą Output & Control: MainJG q¶V„’’Ą Output: CPUE, Catch vs Biomass63 ;k4„’’€€€Title Page2. [«„’’Ą NoiseNJ ĶS„’’Ą Output & Control: Gear EfficiencyRM qV„’’Ą Output & Control: Environment Effect*( L S$`‚ ’€€€€€€ *( l T‘Y‚ ’€€€€€€ &# ä ^ņl©#¼508,,Graph²® ņ©6„<’ĄĄCentury GothicThe effect that fishing activity (and/or natural ecosystem variation) has on the supporting ecosystemFA %U„’’Ą Output: Mean Biomass Age4ų *18CNTZ`flrxƒŽ”šŖµĄĖę *:M`s„—„²ĘŪįüH”7Læō$*( |p¤4 *( 0;Ø ’ *( œ —`,  Ü ŅŅ_( Ü ń© "*( Œ ńĻ2( *( ¬ ŠA= Ē©d©Æėį’*Ó÷=D°*( ¼ k"  *( Ģ "ó5 @ŗ@öˆ>< 6MK’ (from Sterman 2001)*& . j7īf<0,WHITE_NOISE*% † V7*fœ<0,PINK_NOISE*'  Q`2›<0,PINK_NOISE_2jg Āŗg.’Ą’Ą€Arialchange to non-zero for "noise"nj ¹š<<’’ĄArialclick here to return to main view*( \Ći ’€€€€€€ v@(ėB? ż;„’Ą’’ Model: Fish Population>; ž=„’ Ą’’ Model: Management JE gćX„’’Ą Output & Control: ManagementJH gV„’’Ą Output & Control: Fishing UnitsJF äT„’’Ą Output & Control: RecruitmentB? µ’Y„’’Ą Output & Control: MainJG ĘV„’’Ą Output: CPUE, Catch vs Biomass63 Ó4„’’€€€Title Page2. Æ„’’Ą NoiseNJ S„’’Ą Output & Control: Gear EfficiencyRM ĘåV„’’Ą Output & Control: Environment Effect@l`jf 1¢ų„=’€’Ą’Century GothicCreation of Pink Noise StreamFA zęU„’’Ą Output: Mean Biomass Age*( Ć/( ’\\\€€€ *( Ćo2€’€€€€€€ ˆH”7LæWWōģ:•,G¦€?•<:•Œ%•œ•¬:•ÜG•Œ¦:•ģG•ü¦J(•$$•,•œ•<*4 •\¦€?r<&•|Œ00&•\¦€?H•œ•¬¦€?‚L0•¼Œ00&•Ģ¦%•Ü•|%•ģ•|:_7•¬'•ü•  h=•œ0¦¦¦€?¦€?¦¦¦Ņ>¦1!=¦®œ]>¦ō“=¦¶…Ÿ>¦ŗ02>¦=Š>¦I˜>¦é?¦ µį>¦śÕ?¦"Ž?¦£*?¦lé9?¦śÕ8?¦”Q?¦&üJ?¦Że?¦qvk?¦–?{?¦€?¦€?b E•Œ00&•,¦•<•LjÆK•\G$•Ü•ģ%%•l••|¢æQ•ŒŒ0 0-•|•œ%%•|•¬•%%•œ•¬•:Ö]•<H•¼•Ģ*ąf•L¦*čn•,¦ŗšv•¼0¦¦¦ A¦€?¦¦33s?¦-&Ņ?¦°«