Amendment No. 4 to the Fishery Management Plan for the Stone Crab Fishery of the Gulf of Mexico and the South Atlantic

AMENDMENT 4 TO THE FISHERY MANAGEMENT PLAN FOR THE STONE CRAB FISHERY OF THE GULF OF MEXICO (Including Environmental Assessment Gulf d Mcdeo Fishery MaMgemcnt C o u d l Tamp., Hod& 33609 5401 west Kennedy Bodmrd, Suite 881 8l3-228-28U NOVEMBER 1990 I. Introduction The Fishery Management Plan for the Stone Crab Fishery of the Gulf of Mexico (FMP) was implemented on September 30, 1979 (44 FR 53519). The FMP resolved im armed conflict over competing gear use between stone crab and shrimp fishermen operating in the EEZ off Southwest Florida and extended Florida's rules regulating the fishery into the EEZ. The management area of the FMP is limited to the EEZ seaward of the west coast of Florida in the Gulf of Me& (Gulf). The FMP has been amended three times. Amendment 1 was implemented on November 8, 1982 (47 FR 41757), and specified a procedure for evaluating the area zoned to resolve the conflict. Amendment 2 s* was implemented on August 31, 1984 (49 FR 30713), and established p r z d ~ e s for resolving gear -"-.. conaicts in Central West Florida. Amendment 3 was implemented on September 25, 1986 (51 FR 30663), and included management measures to enhance survival of crabs held on board and prohibited harvest of egg-bearing female crabs. This Amendment contains provisions for adding a scientifically measurable definition of overtishiug and an action plan to arrest overf~bing should it occur as required by the Magnuson Act National Standards (50 CFR 602), and a section on vessel safety considerations and a revised habitat section as required by the Magnuson Act. 11. Descri~tioo of the Fishen and Utilization Patterns The FMF', as amended, provides for management of the fishery in the EEZ off the west coast of Florida. The fshery is managed jointly by the State of Florida and the Gulf of Mexico Fishery Management Council (Council). The ftshery is largely commercial with limited recreational participation confined to the near-shore waters within state jurisdiction. The fishery is unique in that only the claws are harvested, and the live crabs with one or both claws removed are returned to the water. Data from Florida Department of Natural Resources (FDNR) studies indicate 3 to 8 percent of these crabs regenerate claws that may be harvested in a subsequent season (Amendment 3). Claws regenerate to approximately 70 percent and 100 percent of their original (pre-autotomy) size one and two molts after de-clawing, fespectively in (RestfEpo, 1989). Figure 1 indicates the trends in the fshery in terms of traps deployed, catch (or landings) of claws, and annual catch per trap. Landings and number of traps deployed increased in similar linear trends until 1981 (at the level of approximately 350,000 traps). After that time, increases in number of traps did not result in increased landings and landings have fluctuated around 2.0 million pounds, indicating full -7 exploitation. Annual catch per trap (CPUE) declined from the 1960% r e m z e d essentially stable from 8 1974 to 1981, and declined thereafter to a level of approximately five pounds of claws per trap. The Scientific and Statistical Committee (SSC) in reviewing these data concluded that increases in traps beyond the 1981 level (approximately 350,000 traps) in addition to not increasing landings probably did not increase fshing mortality. Essentially, the increases just further overcapitalized the industry through gains in excess fshing capacity without impacting the resource. The SSC indicated that total traps deployed in the fishery was a poor bench mark for examining CPUE trends since many fishermen fished in the spiny lobster fshery in the first part of the stone crab season. Also as indicated by the Stone Crab Advisory Panel (minutes, 1983), fshermen tend to deploy excess traps in certain areas to reserve fshing areas weeks before the crabs migrate into that area or the traps are fished. 111. Statement of the Problem NMFS in July 1989, published revised guidelines for fshery management plans that interpretatively address the Magnuson Act National Standards (50 CFR, Part 602). These guidelines require each plan to include a scientifically measurable definition of o v c ~ and an adon plan to arrest over£isw should it occur. The FMP for stone crab is being revised by this amendment to comply with the guidelines and to include a section on vessel safety considerations and a revised habitat section as required by amendments to the Magnuson Ad. The actions proposed in this amendment to the FMP are as follows: o inclusion of a FMP section on Overfishing o indusion of a FMP section on Vessel Safety Considerations 2 o revision of the FMP section on Habitat of the Stocks A m O N 1: OVERFISHING Promsed Alkrnativeg 1. lkflnition of OvHnshing: " O v e ~ exists when the realized egg produdion per recruit is reduced below 70 percent of potential produdion (see Flgurcs 4 and 5). Overfkhg will be avoided when there is a minimum daw length (length of propodus; Ftgure 2) that assures survival of the aabs to achieve the 70 percent ege production per recruit potential' 2. to k u t Should oytrfisthg occur, tht Council and State of Florida will adjust the minimum claw length or fishing mortality rate (F) by regulatory amendment as authorid under this measure to inacasc the egg production potential to at least 70 percent. The SSC in reviewing the adyscs for stone crab from the NMFS SEFC Over6shing Workshop (February 12-14.1990) concluded that at the current minimum claw length (70mm = 2 3/4 inches), recruitment overfishing is unlikely. That is because on the average males and females mature at age 2 (50 percent maturity), the male crusher and pincher claws reach legal length between age 2 and age 3, and female claws reach legal lengths one to two years later (Figure 3). Therefore, females spawn for at least one or more years before - entering the fishery. Restrepo (1989) suggested the egg production potential is largely independent of the male/female ratio in the population since a single copulation fertilizes a female for the season and males can copulate several females. Therefore, the fact that males enter the fishery at earlier ages and may be reduced relative to the number of females does not appear to impact egg production potential. Females are capable of producing up to 13 batches of e w after a single copulation (four to five batches on the average) during the reproductive season. Fecundity is linearly related to size and large females producc-ds of 350,000 eggs per ,""L batch. Therefore, at the present minimum claw length of 70mq more than 70 percent of potential egg production will be maintained over a wide range of tishing mortality rates, both higher and lower than the present mortality rate (Figures 4 and 5). ~- -....... .- .. - ~ , ~ . -. .. - - ~ - . In addition to the protection from ovedkbg as a fundion of egg produdion potential afforded by the current minimum claw length, several other management measures enhance this protection. Harvest is prohibited by a closed season during the principal months femaies are canying gravid eggs (May 15 to October 15). Egg bearing females must be reieased unharmed imm&ely, ie, possession at any time is prohibited. All aabs held aboard a vessel must be kept damp and in a shaded container before &clawing to inaease survival rates of aabs returned to the water (LC., lab stpdw indicate about 75 percent survival over six hours by periodically wetting the ah). There is no allowabk tolerance for potsasion of undersized daws and no legal market for them. AU of these measures provide additional protection against overfishink Although ovedkhiq should nat occur under the current fishery management measures, Ehrhardt and Restrepo (1989) and Restrepo (1989) concluded that yield per recruit (YPR) in tenns of weight could be haeased by reducing existing minimum claw size. Bert, ct. al. (1986) suggested stone crabs live to be about 6 years old. Also, females do not fully enter the fishery until age 5 (Figure 3). Therefore, the potential exists for reducing the minimum claw size at some future time to obtain a greater YPR. However, as Restrepo (1989) indicated this may affect the reproductive capacity of the stone crab population (see Figures 4 and 5). Another significant consideration of any such action to reduce the minimum daw size is the economic impact it would have on the - fishermen. Although gains in poundage landed would be achieved, that action may result in losses in total exvessel value since there is a significant price differential between claw sizes. For example, during the 1988-1989 season, claws landed were -ed as follows: 5 percent jumbo, 48 percent large, 25 percent medium, 9 percent small, and l3 percent unclassified (Sutherland, 1989). Current exvessel prices per pound (1989-1990 season) are $655 for jumbo, S6.U for large (the majority of landings), and $5.49 for small. Since the small classification are claws just exceeding the minimum size limit, the creation of a market classScation below that size would likely < --- %k .-I result in a lower exvessel value that would have to be contrasted against gains in poundage. Analvscs Related to Pronosed A l t e r n a t ~ ~ Figures 4 and 5 from the Overfishing Workshop report present isopleths that relate potential egg produdion per recruit to various levels of fw mortality (F) and minimum daw size. Flgure 4 uses a natural mortality (M) level of 1.9 which is the upper bound of the range of &mates (1.9 to 0.95) and also assumes trap selectivity by size. It is presented as the bwt case scenario for the relationships. Flgure 5 uses the lower boundary of M and assumes no trap seledivity. It is presented as the worst case scenario. The tnrc relationship lies between the two casts. The tstimates of fbhiq mortality rates (F') havc ranged between 0.75 and 4.1 per seeson (Bert, et. aL 1986, Restrepo 1989, and Ehrhardt 1990) and F varies by sex and size (or age) of aabs. The best s t h a t e of current F is approximately 20. The Overfishing Workshop report suggested a safe limit for egg production potential per recruit be set at no lower than 70 percent in the absence of more definitive information. Utilizing the hple th of Figure 5, minimum claw siw at 70 percent of egg production potential per recruit are as follows: . Since the worst case scenario was used to be conservative for this amendment, the minimum claw size at which overtlshing would occur is defined at 665mm. This standard may be changed by regulatory amendment as better data result in selection of the best isopleth for describing tbis relationship. E c o l w I m ~ m : Since the current minimum size has maintained egg production potential at a high level and since neither the Council nor the Florida Marine Fisheries Commission (FMFC) p r o m to reduce the minimum -- -i 8 -2 size, the long-term impact should be a stable 6shery without the OCwTence of overfishing. The current expression of overfishiag at a minimum claw length of 665mm was a n i d at very conservatively by using a relatively high level of egg production potential per recruit (i.e, 70 percent) and the worst case scenario from a series of isopleths. Therefore, ihe possibility of overfishing occurring even at that minimum size is unlikely. However, the methodology used in establishing the defhition provides a method of monitoring the reproductive potential and condition of the stock that will become more precise as better estimates of M, F, and the age structure of landed aabs are derived and as more reliabIe isopleths relating these parameters to egg production are computed. In the interim, the propowl management measure allows adjustments by regulatory amendment of claw size or fkhhg mortality rate to maintain a 70 pertxnt egg prodnuion potential per recruit. All of the analyses and discussion of Action 1 apply to the stone a& which constitutes more than 90 percent of had@, While & o c m in northwest Florida, its life history, though less documented, appears to be esentdy the same. It is the judgement of the Council that the definition of w t r f d h g and proposed management measure afforda the same degree of protection to XaQipe There are no direct impacts on the fishermen or economy as a result of the p r o p a d alternative. If any actions are taken by regulatory amendment under the proposed measure, the impacts of those actions will be included in the Regulatory Impact Review as part of that regulatory amendment. The maintenance of a stable fshery - without overfihing occurring, as appears to be the case under the current mapagement practices of the FMP and FMFC, has very beneficial long-tenn impacts. Alternative No action - Status Quo. : The current .rules under status quo established by FDNR, FMFC, and the Council appear to assure overfishing will not occur provided the rules arc not altered. Based on the provisions and analyses of the proposed alternative, it is unlikely that the rules affecting reproductive potential will be changed. The proposed alternative, however, is superior to status quo by providing a method of monitoring the reproductive potential and condition of the stock and instituting the corrective actions necessary to prevent recruitment o v t ~ The effeds are wstntially the same as the p r o p o d alternative with the exception that the p r o j w d alternative provides a method to measure the stock reproductive potential and condition and to take c o d e actions. .None are associated with the status quo alternative. 8 ON 2: YESSEL SAFETY CONSIDERATIONS Section U.0 of the Fh4P is modified by adding a new subsection l3 (x), Vessel Safety Considerations, to read as follows: No management measures included in the FMP or in this Amendment adversely impact vessel safety that would result from weather or unsafe ocean conditions through constraint placed on access to the Fishery. Fshermen may harvest stone crabs at any time during the fshing season (October I5 to May 15) and thereby may avoid unsafe conditions. Geographical areas where there is extreme competition for 6sking grounds bttwten trawl--- T:~ and trap gear are zoned to provide exclusive f k b g grounds for each gear. ACI'ION 3: M I T A T OF THE STOCm . Section 6.0 of the FMP is revised by adding a new Description of the Habitat of the Stocks which is included in the Amendment as Appendix A. Tbe actions proposed in the Amendment have no adverse impact on the physical environment. The effect of these actioas is to amend the FMP to indude a measurable definition of overfishing that allows monitorhq of the fishery and a management measure to prevent overfishing. The proposed adions of the Amendment have no anticipated impad on threatened or endangered species or marine mammals. A Section (7) Consultation was held for the fishery with "no jeopardy opinion" being rendered. W . conclusion^ - . Mitieatine Measures Related to the Pro~osed Action None. Unavoidable Adverse I m ~ a c t ~ None. Relationshi0 Between Local Short-Term Use of the Resource and Enhancement of Low-Term Productivity No impacts on short-term use are anticipated. Long-term productivity should be enhanced by implementation of a system that will prevent overfshing. Irreversible or Irretrievable Commitment of Resources The federal management commitment will be slightly inaeased by analyses associated with monitoring of condition of the stock. Findinns of No Simificant Environmental Imoacf Having reviewed the environmental assessment and available information related to the proposed actions, I have determined that there will be no siwcant environmental impact resulting from the proposed actions. .Assistant Administrator for Fisheries Date RESPONSIBLE AGENCIES Gulf of Mexico Fishery Management Council Lincoln Center, Suite 881 5401 West Kennedy Boulevard Tampa, Florida 33609 813-228-2815 National Marine Fisheries Service Duval Building, 9450 Koger Boulevard St. Petersburg, Florida 33702 813-893-3141 LIST OF AGENCIES AND PERSONS CONSULTED Gulf of Mexico Fishery Management Council Stone Crab Advisory Panel Scientific and Statistical Committee Florida Marine Fisheries Commission National Oceanic and Atmospheric Administration (NOAA) General Counsel's Office (SERO) National Marine Fisheries Service Division of Fisheries Management Southeast Fisheries Center LIST OF PREPARE Gulf of Mexico Fishery Management Council Wayne Swingle, Biologist, Drafter (Editorial Assistance from Personnel of Agencies Consulted) National Marine Fisheries Service Joseph Powers, PhD., Population Dynamics LOCATION AND DATES OF PUBLIC HEARINGS The Council accepted written comments on the amendment through November 9, 1990. Public hearings were held as follows: Qctober 25.199Q November 14. 199Q Marathon High School Cafeteria Omni Hotel at Westshore 350 Sombrero Beach Road 700 North Westshore Boulevard Marathon, Florida Tampa, Florida 6:00 - 7:30 p.m. 8:45 - 9:30 a.m. LITERATURE CITED IN AMENDMENT OR OVERFISHING WORKSHOP REPORT Bert, T.M. 1986. Speciation in western Atlantic stone crabs (genus Menippe): the role of geological processes and climatic events in the formation and distribution of the species. Marine Biology 93: 157 170. Bert, T.M., R.E. Warner, and L.D. Kessler. 1978. The biology and Florida fishery of the stone nab Meni~De mercenaria (Say) with emphasis on southwest Florida. Florida Sea Grant Technical Report Number 9. University of Florida Sea Grant Program, Gainesville, Florida. Bert, T.M., J. T i a n t , J. Dodrill, and G.E. Davis. 1986. Aspects of the population dynamics and biology of the stone crab (m mercenaria) in Everglades and Biscayne National Parks as determined by trapping. Report SFRC-86/04. National Park Service South Florida Research Center. Bert, T.M., and R.G. Harrison. 1988. Hybridization in western Atlantic stone crabs (genus M ~ u ~ D D ~ ) : evolutionary history and ecological context influence species interactions. Evolution 42(3):528-544. Ehrhardt, N.M. 1990 (in press). Mortality and catchability estimates for the stone crab ( M e n i ~ ~ mercenariq) - --- > =+. in Everglades National Park. Bulletin Marine Science. ,-'A . Ehrhardt, N.M. and V.R. Restrepo. 1989. The Florida stone crab fishery a reusable resource? Pages 225-240 in J.F. Caddy (ed.): Marine Invertebrate Fisheries: Their Assessment and Management. J. Wiley and Sons, New York. Florida Department of Environmental Regulation. Coastal Zone Management Plan (numerous volumes and annual appendices to progiam). Tallahassee, Florida. Lindberg, WJ., and MJ. Marshall. 1984. Species profiles: Life histories and environmental requirements of coastal fshes and invertebrates (south Florida) - stone crab. U.S. Fish and Widlife Service Biology Service. FWS/OBS-82/11.21. Washington, D.C. U.S. Army Corps of Engineers TR EL82-4. Restrepo, V.R. 1989. Population dynamics and yield-per-recruit assessment of southwest Florida stone crabs, Menip-pe rnercenaria. Ph.D. dissertation, University of Miami, Coral Gables, Florida. Savage, T., J.R. Sullivan, and C.E. Kalman. 1975. An analysis of stone crab (Menippe mercenaria) landings on Florida's west coast, with a brief synopsis of the fshery. Florida Department of Natural Resources, Marine Research Laboratory Publication Number U. St. Petersburg, Florida. Sutherland, D.L. 1989. Florida Stone Crab Landings and F ~ h i n g Effort, 1962-1988. NMFS SEFC, Coastal Resources Division, Contrib. Number CRD-88/89-20. 22p. Wilber, D.H. 1989. Reproductive biology and distribution of stone crabs (Xanthidae, Meni~m) in the hybrid zone on the northeastern Gulf of Mexico. Marine Ecology Progr. Service 52:235-244. Williams, A.B. and D.L. Felder. 1986. Analysis of stone crabs: M e n i ~ ~ e mercenaria (Say), restricted, and a previously unrecognized species described (Decapoda:Xanthidae). Proc. Biology Soc. Washington 99: 517-543. h a d P"m: C . % : 8"o: 5 . V . *=: u . 0 . 0 m 0 . 0 QlW 0 . + . 0 , . . . . . . . . . , . . . . . . . . . a u 7 0 n a n m Fishing Season J O l ................... a a m m a m ( 0 ...... ~ . . . . . . Fishing Season k................... 1 1 ) m m 1 1 m 1 ) 1 0 Fiahing % a m FIGURE 1: Fishing season ( k t 15 - Hay 15) trends I n a) trap capaclty. b) catch. and c) catch per trap capacl t y for the Florida west coast stone ' crab fishery. s h g t a crab and i t 8 &.la. (thm u j o r claw, m ~ r u h a r m and tlaa minor claw, orr wphcarrO)O Body 1- fa w n o n l y .rrmamd u campa- width claw a i m i a maa.ur.6 8s propod- 1.PIQfh. 120 . 100 1 1 1 1 , 1 , , , 1 1 0 12 24 36 U) 60 72 84 96 108 AGE (months) FIGURE 3: Claw g M cums for storm crabs. IC males; F fanales. PL . plncer length; CL = crusher length. Egg Production Potential, High M 90.0 2 . Seasonal F FIGURE 4: Egg production per recrui t isopleths for female stone crabs under a scenario with high natural mortal i t y (13.1.9) and trap s e l u t i v i ty. Values are given as a f ract ion o f those expected i n an unexpl o i ted stock. Egg Production Potential, Low M Seasonal F FIGURE 5: Egg production per recrul t isopleths f o r fanale stona crabs under a scenario with lomr natural mortality ( M . 9 5 ) and full t rap retention. Values are glven as a f rac t ion o f those expected I n an unexplol ted stock. APPENDIX A 6.0 DESCRlVLlON OF HABITAT OF STOCK COMPRISING MANAGEMENT The following subsections were reviewed in comparison ta the most recent literature on stone crabs and were judged as adequate descriptions without further revisions except for the indicated notes: (9 Condition of Habit& (A) . . e s c r ~ ~ t ~ o u of Stone Crab Hablu . . a. Habttat occu~led d the lrfe b to rv of &: Bert (1986), based on electrophoretic studies, suggated t h a t x mer- was= % ,- L a taxonomic supergroup composed of two subspecies, one which inhabits the western most part of the range, from northwest Florida to Texas, and the other the eastern part of the range. Williams and Feider (1986) dwignated crabs in the western part of the range as a different spedes & Bert et. aL (1989) suggest a hybridization zone between & ~erc tnar ip and J& around the Cedar Key, Florida area. WJber (1989) concluded the two species and hybrids share similar life history charaderistics in terms of seasonal growth, reprodudion, and movement. b. aloug- of Florida (B) R o d u ~ t v . . a& . . Note ID: Thison discmcs threats to the habitat. m: Thcrc arc no known pollution sources or habitat conditions that a£fed the abiity to hamst and market stone aaba (ii) (iii) (A) e &&: Florida has an approved Coastal Zone Management Program that provides comprehensive protection from habitat degradation in the coastal zone. The program incorporates by reference all Florida laws and regulations pertaining to habitat alteration, discharges, project siting, marine bheries, etc., it., all statutory programs related to the marine environment. Consistency determinations of activities proposed in the coastal zone must be obtained from the program office within the Department of Environmental Regulation. (B) . . &&m Federal P r m &&: The following two subsedions are added: r. Matine Sanctuaries Act. Under this program, N O M e s s W e s marine sanctuaries, - =$ 1% L to protect areas of unique environmental or historical importance and promulgates and 'enforces rules to prevent habitat alteration within the sanctuaries. s. Waterways Safety Ad of 1978. The Act charges the U.S. Coast Guard with marine environmental protection which includes principal rtspoasiiility for oil spill enforcement and clean up. t. Outer Continental Shelf Lands Act. In administering the oil and gas resources o n the Outer Continental Shelf, the Department of Interior through the Minerals Management Service has the authority to require that the oil a d gas lease permit stipottions protect the environment. U. Clean Water Act. The Environmental Protection Agency is the permitting agency for chemical dkbaqp into the Gulf of Mexico, under the National Pollution Discharge . . . Ehmatmn Sydtm (NPDES) program of the Clean Water Ad for chemicals used or produced ia the Gulf (LC, drilling muds, produced water, or bioddes). (C) B& In addition to laws cited, the Coastal Zone Management Program has incorporated by reference all statutes and rules applying to the marine environment (Florida Department of Environmental Regulation). The following new subsections arc added: (iv.) Habitat Information Nee& The foliowing research needs relative to stone a a b habitat are prqvided so that state, federaL- =+ ,a and private research efforts can focus on those areas that would allow the Councils to develop measures to better manage stone aabs and their habitat (see FMP Operations Plans): # 1. Determine patterns of dispersal of all life stages, including movement patterns, recruitment areas, aad nursery areas; 2 Define temporal and spatial variation in larval and juvenile distribution and abundance, &cularly in southwest Florida; 3. Determine the effect of environmental factors on abundance and catch levels, esp&ally those related to reauitment rates, post-dement surviva, and catchability o o e u 4. Determine the effects of lost or abandoned traps upon stone aab habitat; , 5. Identify optimum environmental and habi i conditiom and those that limit stone aab production; 6. Identify additional areas of particular concern for stone aab life history stages; 7. Determine methods for restoring stone crab habitat and/or improving existing environmental conditions that adversely affect habitat; and, 8. Identify mitigative methods for preserving and/or establishing habitat. (v.) Habitat Recommendationf - . The stone crab resources contribute to the food supply, economy, and health of the nation and provides for recreational and commercial f~bing opportunities and aesthetic enjoyment. The continued use of these resources can only be assured by the wise management of all aspects of habitat. haeased productivity may not be possible without habitat maintenance and regulatory restrictions. < - - - - =% ;=-,. Recogni2ing that all species are dependent on the quantity and quality of their essential habitats, it is the policy of the Council to protect, restore, and improve habitats upon which commercial and recreational marine hheries depend to inaease their extent and to improve their productive capaaty for the benefit of the present and future generations. This policy shall be supported by three objectives which are to: 1. Maintain the current quantity and produdin capacity of habitats supporting important commercial and recreational fisheries, including their food base (this objective may be accomplished through the recommendation of no loss and minimhtion of environmental degradation of e s i h g habitat); 2. Restore and rehabilitate the produdive capacity of habitats which have already been degraded; an4 3. create a d develop produdive habitats where increased fishery productivitywillbcnefit To achieve these go& the Council has formed a Habitat Rotedon Committee and Advisory Panels. The purpose of the committee is to bring to the Council's attention a d t i c s that may affed the habitat of the fisheries under their management. The Council, pursuant to the Magnuson Act, will use its authority to support state and fcdcral environmental agenda in their habitat conservation efforts and wil l d h d y engage the regulatory agencies on significant actioas that may affect habitat. The goal is to ensure that habitat losses arc kept to the minimum and that efforts for appropriate mitigation strategies and applicable research are supported.