Steele et al Efficiency of bycatch reduction devices in small otter trawls in thie Flonda sfirimp fisfiery 



339 



ing depth >1() f'atiioms llnil) to '2.5:1 (fishing depth < 10 

 fm) (NMFS'i; thus total finfish bycatch can be estimated 

 at 26.0-28.3 niilhon kg for the Florida Gulf shrimp fishery. 

 With the finfish-to-shrimp ratio of of 2.8:1 for the South 

 Atlantic fishery and the current landings information for 

 Florida, the finfish bycatch for the Florida Atlantic shrimp 

 fishery can he estimated at 5.0 million kg. Since 1990, con- 

 siderable research has been conducted to characterize by- 

 catch composition and to develop methods to reduce by- 

 catch in the Gulf and the South Atlantic shrimp fisheries 

 (Nance, 1992. 1993: GSAFDF-'; Nichols et al.^; NMFS^). 

 In addition, numerous fishery-independent sui-veys exam- 

 ining bycatch characterization and the efficiency of by- 

 catch reduction devices (BRDs) have been conducted by 

 state and private organizations throughout the southeast- 

 ern U.S.A. (Burrage et al.''). 



In 1990, the Florida Marine Fisheries Commission (FM- 

 FC; now Florida Fish and Wildlife Conservation Commis- 

 sion) began to develop a shrimp fishery management plan 

 that included a mandate to reduce the bycatch of total fin- 

 fish biomass in shrimp trawls by 50'^'f . Responding to this 

 policy decision, a bycatch-characterization study of the 

 inshore Florida shrimp fishery was conducted statewide 

 (Coleman et al.~; Coleman et al.'*). Field studies compar- 

 ing the efficiencies of two types of BRDs (Florida fish eye 

 [FFEI, large-mesh extended-mesh funnel (EMF) ) in otter 

 trawls and rollerframe trawls were also conducted (Conti- 



nental Shelf Associates Inc.^; Coleman and Koenig'"; Cole- 

 man et al."). 



The issue of bycatch in the Florida shrimp trawl fishery 

 has exacerbated conflicts between conservationists and rec- 

 reational and commercial fishermen over the allocation of 

 marine resources. Relevant issues include the following: 1) 

 the high mortality rates of economically important juvenile 

 finfish caught in shrimp trawls, which could reduce har- 

 vestable finfish stocks; 2) the high mortality rates of non- 

 harvested species caught in shrimp trawls, which could al- 

 ter the overall health of the marine environment; and 3) the 

 perceived waste of bycatch species that are discarded. 



This controversy was partly responsible for the passage 

 of a Florida constitutional amendment (Article X, Section 

 16) that reduced the size of shrimp trawl nets used in the 

 coastal shrimp fishery to 500 sq. ft. (45 m-) of mesh area 

 per net and limited the number of nets to two per vessel. 

 In previous studies conducted in Florida to examine the 

 efficiency of BRDs in shrimp trawls (Coleman and Koe- 

 nig'"), net sizes gi'eatly exceeding that authorized by the 

 amendment were tested. The goal of our study was to test 

 how efficiently the FFE and EMF excluded finfish in small 

 otter trawls (overall mesh area=45 m-) of various mouth- 

 perimeter sizes. This information can be used by fisheries 

 managers when considering the use of BRDs in inshore 

 and nearshore shrimp fisheries. 



* GSAFDF ( Gulf and South Atlantic Fisheries Development Foun- 

 dation). 1993. Organization and management of a Gulf of 

 Mexico and south Atlantic Ocean fishery bycatch management 

 program (year 21. Final report to National Marine Fisheries 

 Service (award NA37FD0032). GSAFDF, Suite 997, Lincoln 

 Center, 5401 West Kennedy Boulevard, Tampa, FL 33609. 65 p. 



^ Nichols. S.. A. Shah. G. J. Pellegi-in Jr., and K. Mullin. 1990. 

 Updated estimates of shrimp fleet bvcatch in the offshoi'e waters 

 of the U.S. Gulf of Mexico, 1972-1989. Report to the Gulf of 

 Mexico Fishery Management Council, The Commons at River- 

 gate 3018 US.'Highway 301 N., Tampa, FL 33619. 



'' NMFS (National Marine Fisheries .Service). 1995. Coopera- 

 tive research program addressing finfish bycatch in the Gulf 

 on Mexico and south Atlantic shrimp fisheries: a report to Con- 

 gress. National Marine Fisheries Sei-vice, Southeast Fisheries 

 Center, Southeast Regional Office, 9721 Executive Center Drive, 

 St. Petersburg FL 33702, 68 p. 



•^ Burrage, D. D., S. G. Branstetter, G. Graham, and R. K. Wallace. 

 1997. Development and implementation of fisheries bycatch 

 monitoring programs in the Gulf of Mexico. Report to the U. 

 S. Environmental Protection Agency (report MX-994717-95-0). 

 Mississippi State LIniversity, P.O. Box 5325, Mississippi State. 

 MS 39762, 103 p. 



 Coleman, F C, C. C. Koenig, and W. F Herrnkind. 1991. 

 Survey of the Florida inshore shrimp trawling bycatch and 

 preliminary tests of bycatch reduction devices. First annual 

 report to the Florida Department of Natural Resources. National 

 Marine Fisheries Service MARFIN gi-ant NA37FF0051. Insti- 

 tute for Fishery Resource Ecolog>', Florida State Univ., Tallahas- 

 see, FL 32306,25 p. 



8 Coleman, F C, C. C. Koenig, and W. F Herrnkind. 1992. 

 Survey of the Florida inshore shrimp trawling bycatch and 

 preliminary tests of bycatch reduction devices. Second annual 

 report to the Florida Department of Natural Resources. National 

 Marine Fisheries Service, MARFIN Grant NA37FF0051. Insti- 

 tute for Fishery Resource Ecology, Florida State Univ.. Tallahas- 

 see. FL 32306.21 p. 



Materials and methods 



Tampa Bay is located on the west-central coast of Florida 

 (Fig. 1) and is the largest open-water estuary in the state 

 (Lewis and Estevez. 1988). The bay is a subtropical estu- 

 ary that has patches of fringing seagrass meadows (Lewis 

 et al., 1981), but fine sand is the predominant seabottom 

 type (Brooks'-). 



Gear specifications 



Conventional semiballoon otter trawls (Fig. 2) are used 

 to harvest pink shrimp (Farfantepenaeus duorarum) in 

 Tampa Bay. Otter trawls are typically used on unvege- 

 tated, sandv-bottom areas. We tested the effectiveness of 



'■'Continental Shelf Associates, Inc. 1992. Commercial food 

 shrimp fishery impacts on by-catch in the lower St. Johns River, 

 Flonda. Draft final report C-7238. Continental Shelf Associ- 

 ates, Inc., 759 Parkway Street, Jupiter. FL 33477. 35 p. 



'"Coleman. F C. and C. C. Koenig. 1994. Flonda inshore 

 shrimping: experimental analysis of bycatch reduction. Final 

 report. National Marine Fisheries Service. MARFIN grant 

 NA37FF0051. Institute for Fishery Resource Ecology, Florida 

 State Univ., Tallahassee, FL 32306,63 p. 



" Coleman, F.C., P. Steele, and W.Teehan. 1996. Use of bycatch 

 reduction devices in small trawls of sizes set by the net ban. 

 Final Report. Florida Department of Environmental Protec- 

 tion contract MR081. Florida Dep. Environ. Protection. 100 

 8'*' Avenue S.E., St. Petersburg, FL 33701, 75 p. 



'- Brooks, H. K. 1974. Geological oceanography. In Summary 

 of knowledge, eastern Gulf of Mexico (J. I Jones, R. R Ring, M. 

 O. Rinkel, and R. E. Smith, eds), p. IIEl-50. Fla. State Univ. 

 Syst. Inst. Oceanogr., St. Petersburg, FL. 



