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Development and Implementation of Fisheries Bycatch Monitoring Programs In The Gulf Of Mexico

Acknowledgment

Many individuals contributed to the development of this report. We would like to thank all Gulf of Mexico Program partners who gave of their time, energy and expertise in creating this document. Special thanks are also due to the numerous state and federal agency personnel who provided the authors with many hard-to-find references. This document has been funded by the United States Environmental Protection Agency under Cooperative Agreement Number MX-994717-95-0 awarded to the Mississippi Agricultural and Forestry Experiment Station of Mississippi State University. The contents of this document do not necessarily represent the views and policies of the Environmental Protection Agency, nor does the mention of trade names or commercial products constitute an endorsement or recommendation.


 

David D. Burrage
Mississippi State University Coastal Research & Extension Center
Sea Grant Advisory Service
2710 Beach Boulevard, Suite 1-E
Biloxi, MS 39531

Steven G. Branstetter
Gulf & South Atlantic Fisheries Development Foundation, Inc.
Lincoln Center, Suite 997
5401 West Kennedy Boulevard
Tampa, FL 33609

Gary Graham
Texas Agricultural Extension Service
Sea Grant College Program
P.O. Box 1675
Galveston, TX 77553-1675

Richard K. Wallace
Auburn University Marine Extension & Research Center
Sea Grant Extension
4170 Commanders Drive
Mobile, AL 36615


TABLE OF CONTENTS


 

 

THE ROLE OF BYCATCH IN FISHERIES
CONSERVATION AND MANAGEMENT

Fishery resources are harvested from Gulf of Mexico waters using a variety of gears and methods. With few exceptions, most of the fisheries have an element of bycatch associated with them. For purposes of this report, "bycatch" includes discarded fish, shellfish, or other organisms which are taken as non-target incidental catch in fisheries. Bycatch includes those fish and shellfish that have no market value, are damaged during harvest, or cannot be legally retained, landed, or sold. Other organisms such as marine mammals, birds, and turtles are accidentally caught and discarded in some fisheries. The fishing event may cause either immediate mortality or the potential for future mortality as a result of gear interactions or handling.

Fisheries in the Gulf of Mexico are prosecuted under a wide range of management regimes. In waters beyond state jurisdiction, many fisheries are managed under federal regulations promulgated by the National Marine Fisheries Service (NMFS) and the Gulf of Mexico Fishery Management Council (Council). Fishery resources taken primarily from state waters are managed by the respective Gulf states, and some species are managed through interstate compacts initiated and developed by the Gulf States Marine Fisheries Commission (Commission). Fishery management, in the Gulf of Mexico and worldwide, has intensified and undergone many changes. Limited entry, ITQ (individual transferable quotas which privatize harvesting rights), trip limits (frequency and landing limits), gear restrictions, area closures, and seasons further restrict the fishing industry. Often more than one management method is employed simultaneously. All of these management options strongly influence bycatch and discard rates either by changing fishermen's behavior or altering the type of fishing technology used.

The discard of bycatch or lower-valued fish (high-grading) is among the most difficult fishery management challenges, making attainment of conservation and economic goals of fishery managers, the fishing industry, and the public problematic (Dewees and Ueber, 1990). Probably more common is bycatch from non-selective harvesting gear. These discards contribute to the fishing-related mortality of many species and are a factor in management decisions such as setting catch quotas and fishing seasons. Fishery bycatch also plays a larger role in the overall balance of the Gulf ecosystem when viewed in light of the fate of discards, predator-prey relationships, and environmental quality.

Bycatch in the Gulf of Mexico is an issue of great concern when viewed in light of the many fisheries which are conducted in the region and the level of effort being expended to harvest fishery resources. Most bycatch research has focused on the commercial shrimp fishery. According to a recent FAO report (Alverson et al., 1994), this fishery ranks fifth in the world in bycatch generated (discard weight per landed target catch weight). Many other fisheries and fishing gears within the Gulf also impact non-target species. These include pelagic and bottom longlines, commercial hook and line, purse seines, trap fisheries, gill and trammel nets, recreational hook and line, finfish trawls, and recreational shrimp trawls. Bycatch in these fisheries is generated by incidental catch of non-target species and release of regulated species which are under- or over-sized or out of season. Given the large area covered, the multitude of fisheries, and an increasing population that heavily uses marine resources, addressing the bycatch issue is a timely endeavor.


OVERVIEW OF GULF OF MEXICO FISHERIES

The fishery resources in the Gulf of Mexico support an extensive commercial and recreational fishery. Due to increased demands for fishery products in the marketplace and an increase in individual leisure time and discretionary income, more pressure is being brought to bear on the fishery resources of the Gulf. It is important to understand the status of the fishery resources and the demands being placed on them. The total United States commercial harvest in 1995 was 9.9 billion pounds or 4.5 million metric tons with an ex-vessel value (price paid to the fishermen) of $3.8 billion. The five Gulf states produced 15 percent (1.4 billion pounds) of this volume and accounted for 19 percent ($725 million) of the value of these landings (NMFS, 1996). Included in these landings are shrimp, the most valuable fishery in the nation; and menhaden, the second largest fishery by volume in the nation. In 1995, marine recreational fishermen in Florida, Alabama, Mississippi, and Louisiana participated in 17 million fishing trips and landed approximately 136 million fish. Thirty percent of all marine recreational angling trips in the nation occurred in the Gulf and these anglers landed 44 percent of all fish reported in 1995 (NMFS, 1996).

According to the latest estimates, there are 33,696 commercial fishing vessels registered or documented in the five Gulf states (NMFS, 1996). Approximately 25,000 of these are classified as "boats" (under five net tons) which are typically used in inshore fisheries such as oyster tonging, gill netting, and crabbing. Over 8,000 units of the commercial fishing fleet are classified as "vessels" (over five net tons). These are the offshore shrimp trawlers, longline and bandit-rigged reef fish vessels, pelagic longliners, oyster dredgers, purse seiners, and finfish draggers. Many of the larger vessels are typically rigged to participate in more than one fishery.

The amount of effort expended in Gulf fisheries can be approximated by examining license sales in each of the Gulf states. The National Marine Fisheries Service also issues permits for several fisheries which are conducted primarily in federal waters. The number of licenses sold in each fishery by state is not a true indicator of the total number of fishermen harvesting Gulf resources because some fishermen purchase several licenses in their own or other states for the same fishery. However, if one distinguishes between resident and nonresident sales, a better approximation can be obtained. Additionally, states vary in the way licenses are issued. For example, some states license vessels, others license individuals, and others do both. Some states have exemptions for certain classes of people regarding license requirements in some fisheries. The following tables are compiled from information obtained from the Gulf States Marine Fisheries Commission (1996) and the National Marine Fisheries Service (1996):

FLORIDA

Type of License

Number Sold FY95

Resident Annual Salt Water Sport Fishing

542,378

Resident 10-Day Salt Water Sport Fishing

56

Nonresident Annual Salt Water Sport Fishing

75,395

Nonresident 7-Day Salt Water Sport Fishing

51,578

Nonresident 3-Day Salt Water Sport Fishing

207,571

Blue Crab Permit

6,082

Stone Crab Permit

7,258

Crawfish Permit

2,463

Spiny Lobster Trap Certificate -- Each Trap

63,470

Shellfish Relaying Permit

20

Shellfish Leases

386

Resident Apalachicola Bay Oyster Harvesting

748

Nonresident Apalachicola Bay Oyster Harvesting

2

Noncommercial Lobster Permits

520

Noncommercial Shrimp Permits

403

Resident Indian River Clam Permit

900

Nonresident Indian River Clam Permit

74

Dead Shrimp Production License - -St. Johns River Only

74

Bait Shrimp -- Statewide

111

Live Shrimp Production License

73

Noncommercial Shrimp Trawling License -- St. Johns River Only

17

Purse Seine*

208

Manatee County Gill Net*

219

Pinellas County Gill Net*

55

Nassau County Gill Net*

0

Hillsborough County Gill Net*

45

Sarasota County Gill Net*

82

St. Johns County Beach Seine

7

License to Take Sardine-like Fish from Pinellas County Waters

5

Pleasure Vessel Registrations

713,413

Commercial Vessel Registrations

34,188

Nonresident or Alien Commercial Vessel Fees

674

Resident Saltwater Products

18,933

Nonresident Saltwater Products

728

Alien Saltwater Products

136

Restricted Species Endorsement

9,503

*These types of license will probably decline drastically due to Florida's recent net ban which was instituted on July 1, 1995.

 

MISSISSIPPI

Type of License

Number Sold FY95

Resident Salt Water Sport Fishing

48,444

Nonresident Salt Water Sport Fishing

6,645

Resident Gill and Trammel Net

220

Nonresident Gill and Trammel Net

4

Resident Recreational Shrimp

503

Nonresident Recreational Shrimp

1

Resident Shrimp Under 30'

347

Nonresident Shrimp Under 30'

3

Resident Shrimp 30' to 45'

389

Nonresident Shrimp 30' to 45'

39

Resident Shrimp Over 45'

449

Nonresident Shrimp Over 45'

65

Resident Commercial Crab

148

Nonresident Commercial Crab

18

Recreational Crab (Resident Only)

3

Charter/Party Boat (Resident Only)

84

Commercial Hook and Line

86

Recreational Oyster (Resident Only)

105

Resident Oyster Tonging

46

Nonresident Oyster Tonging

25

Resident Oyster Dredging

119

Nonresident Oyster Dredging

15

Live Bait Boat

37

 

ALABAMA

Type of License

Number Sold FY95

Resident Annual Salt Water Rod and Reel

39,245

Nonresident Annual Salt Water Rod and Reel

3,769

Resident Commercial Oyster Catcher

707

Nonresident Commercial Oyster Catcher

5

Shrimp Under 30'

757

Shrimp 30' to 45'

222

Shrimp Over 45'

199

Nonresident Commercial Shrimp

242

Resident Recreational Shrimp Boat

1,727

Nonresident Recreational Shrimp Boat

90

Resident Commercial Crab Fisherman

150

Nonresident Commercial Crab Fisherman

3

Resident Commercial Net License (1,200' or Less)

362

Nonresident Commercial Net License (1,200' or Less)

30

Resident Commercial Net License (1,201' to 2,400')

204

Nonresident Commercial Net License (1,201' to 2,400')

42

Resident Purse Seine

2

Nonresident Purse Seine

8

Resident Recreational Net (Not to Exceed 300')

384

Nonresident Recreational Net (Not to Exceed 300')

17

Resident Commercial Hook and Line

60

Nonresident Commercial Hook and Line

0

Resident Charter Boat -- 6 Passenger

70

Nonresident Charter Boat -- 6 Passenger

8

Resident Charter Boat -- 25 Passenger

14

Nonresident Charter Boat -- 25 Passenger

0

Resident Charter Boat -- Over 25 Passenger

1

Nonresident Charter Boat -- Over 25 Passenger

2

 

LOUISIANA

Type of License

Number Sold FY95

Resident Oyster Tong -- Per Tong

181

Resident Oyster Dredge -- Per Dredge

1,084

Nonresident Oyster Dredge -- Per Dredge

45

Resident Commercial Fisherman

15,062

Resident Hoop Net -- Any Legal Number

1,753

Resident Fish Seine -- Any Legal Number

162

Resident Trammel Net -- Any Legal Number

467

Resident Freshwater Gill Net -- Any Legal Number*

1,000

Nonresident Hoop Net -- Any Legal Number

34

Nonresident Trammel Net -- Any Legal Number*

17

Resident Vessel License

14,323

Nonresident Vessel License

1,581

Resident Purse/Menhaden Seine -- Per Seine

57

Resident Shrimp Trawl -- Per Trawl

10,095

Nonresident Shrimp Trawl -- Per Trawl

3,553

Resident Oyster Harvester

940

Nonresident Oyster Harvester

28

Nonresident Commercial Fisherman

1,625

Nonresident Fish Seine -- Any Legal Number

1

Resident Butterfly Net -- Per Net

3,050

Nonresident Butterfly Net -- Per Net

37

Resident Slat Trap -- Any Legal Number

218

Nonresident Slat Trap -- Any Legal Number

0

Nonresident Purse/Menhaden Seine -- Per Seine

1

Resident Crab Trap -- Any Legal Number

3,423

Nonresident Crab Trap -- Any Legal Number

65

Resident Crab Trap Attached to Trotline

321

Resident Eel Pot License

8

Resident Minnow Trap License

136

Resident Mullet Permit

582

Nonresident Mullet Permit

79

Resident Spear Gun -- Per Gun

29

Resident Set Line License

1,185

Nonresident Set Line License

133

Resident Dip/Cast Net License

383

Nonresident Dip/Cast Net -- Per Net

1

Resident Flounder Gig License

25

Nonresident Flounder Gig -- Per Gig

0

Resident Can, Bucket, Pipe, Drum, Tire

66

Nonresident Can, Bucket, Pipe, Drum, Tire

0

Resident Skimmer Net

5,447

Nonresident Skimmer Net

68

Resident Saltwater Gill Net*

781

Nonresident Saltwater Gill Net*

73

Resident Mullet Strike Net*

755

Nonresident Mullet Strike Net*

80

Resident Pompano Strike Net*

34

Resident Saltwater Rod and Reel

3

Resident Spotted Seatrout Permit

73

Resident Saltwater Gill Net for EEZ*

2

Nonresident Saltwater Gill Net for EEZ*

1

Out of State Oyster Landing Permit

13

Resident Soft Shell Crab Shedder

36

Resident Pompano Permit

8

Resident Restricted Species Permit

46

Resident Recreational Saltwater Fishing Season

280,360

Nonresident Recreational Saltwater Fishing Season

6,510

Nonresident Recreational Saltwater Trip -- 7 Days

1,269

Nonresident Recreational Fresh/Saltwater Trip -- 2 Days

27,618

Resident Recreational Hoop Net -- No More Than 5 Nets

4,288

Nonresident Recreational Hoop Net -- No More Than 5 Nets

87

Resident Recreational Slat Traps -- No More Than 5 Traps

746

Nonresident Recreational Slat Traps -- No More Than 5 Traps

25

Resident Recreational Crab Traps -- No More Than 10 Traps

3,116

Nonresident Recreational Crab Traps -- No More Than 10 Traps

15

Resident Recreational Shrimp Trawl -- Per 16' Trawl

4,389

Nonresident Recreational Shrimp Trawl -- Per 16' Trawl

44

Resident Recreational Oyster Tong -- Per Tong

63

Nonresident Recreational Oyster Tong -- Per Tong

1

Resident Recreational Crab Trap -- Per Trap on Trotline

1,549

Nonresident Recreational Crab Trap -- Per Trap on Trotline

10

*These types of license will probably decline drastically due to Louisiana's recent net ban which will be phased in by 1997.

 

TEXAS

Type of License

Number Sold FY95

Resident Recreational Fishing

1,043,764

Lifetime Resident Recreational Fishing

14

Temporary Resident Recreational Fishing -- 14 Day

77,784

Saltwater Sportfishing Stamp

624,218

Special Resident Fishing

7,121

Nonresident Recreational Fishing

47,109

Temporary Nonresident Recreational Fishing -- 5 Day

63,236

Commercial Crab Trap Tag

79,723

Saltwater Trotline Tag

10,395

Resident Commercial Oyster Fisherman

5

Nonresident Commercial Oyster Fisherman

0

Resident Commercial Oyster Boat Captain

413

Nonresident Commercial Oyster Boat Captain

18

Resident Commercial Oyster Boat

343

Nonresident Commercial Oyster Boat

12

Resident Sport Oyster Boat

78

Nonresident Sport Oyster Boat

1

Resident Commercial Fishing Boat (Fresh and Saltwater)

1,334

Nonresident Commercial Fishing Boat (Fresh and Saltwater)

29

Resident Commercial Mussel and Clam Fisherman

108

Nonresident Commercial Mussel and Clam Fisherman

7

Commercial Fishing Boat (Menhaden Only)

15

Resident Commercial Gulf Shrimp Boat

896

Nonresident Commercial Gulf Shrimp Boat

441

Resident Commercial Bay Shrimp Boat

1,529

Nonresident Commercial Bay Shrimp Boat

0

Resident Commercial Bait Shrimp Boat

1,614

Nonresident Commercial Bait Shrimp Boat

0

Shrimp House Operator's Individual Bait Shrimp Trawl Tag

974

Resident General Commercial Fisherman's

4,175

Nonresident General Commercial Fisherman's

45

Resident Commercial Finfish Fisherman's

1,380

Nonresident Commercial Finfish Fisherman's

11

 

FEDERAL

Type of Permit/Endorsement

Number Issued (Most Recent Fishing Year)

Gulf and South Atlantic Shark

1,841

Swordfish

984

Coastal Pelagics (Charter Boats Only)

1,455

Commercial Mackerel (Includes Gill Net Endorsement)

2,839

Commercial Mackerel Gill Net Endorsement

115

Reef Fish (Charter Boats Only)

515

Commercial Reef Fish (Includes Bandit, Longline and Trap)

1,451

Commercial Reef Fish Trap

95

Commercial Reef Fish Bandit

939

Commercial Reef Fish Bottom Longline

436

Red Snapper 2,000 Pound Endorsement

131

Commercial Spiny Lobster

294

Spiny Lobster Tailing Permit

377

 


 

 

OBJECTIVES AND METHODOLOGY

The general goals of the Gulf of Mexico Program regarding fisheries bycatch are to 1) conserve and restore species diversity and health of aquatic resources while allowing sustainable development, 2) assess and monitor the effects of fishing mortality on the health and abundance of living aquatic resources in the Gulf of Mexico, 3) enhance the sustainability of Gulf commercial and recreational fisheries, and 4) identify and assess existing commercial and recreational bycatch data to determine research needs. The specific objectives of this project were as follows:

  1. Conduct a Gulfwide survey of agencies and organizations to determine existing and on-going data and develop a data catalog;
  2. Compile and analyze these data, identify data gaps, and develop a summary document for peer review and publication; and
  3. Assist the Gulf of Mexico Program with information and technology transfer activities addressing fishery bycatch in the Gulf of Mexico by disseminating information developed under this project to a wide variety of user groups, fishery managers, and the general public.

The methodology used in preparation of this report encompasses more than the original scope of work specified by the Gulf of Mexico Program. The authors made a conscious decision to expand the search for relevant information beyond "a Gulfwide survey of agencies and organizations" in order to include work done outside of the region involving species which are also indigenous to the Gulf of Mexico. Similarly, work done in other areas with the same fishing gear types used in the Gulf but targeting different species was sometimes included in the analyses so that a variety of research techniques and protocols could be compared and evaluated. It is hoped that experience gleaned from this wider examination of bycatch research will be useful in shaping future efforts in the Gulf of Mexico region. Cooperators in the project conducted a survey of agencies and organizations to identify existing data. Contact points were state and federal fishery management agencies, private sector fishery organizations, academic researchers, environmental entities, the Sea Grant advisory network, the Gulf States Marine Fisheries Commission, and public/private organizations such as the National Fisheries Institute and fisheries development foundations. Data were compiled using computer and literature searches as well as individual personal contacts throughout the Gulf region. Much of the documentation associated with this effort is in the form of grant final reports, or reports to agencies, and some of it is preliminary. More detailed and conclusive peer-reviewed literature is likely forthcoming. The project collaborators divided their efforts based on their respective knowledge of the fisheries, fishing gears, and fishing techniques used to harvest living marine resources from the Gulf of Mexico region. The findings in this report are presented according to a classification based on individual fisheries and major gear types used. Wherever practical, citations include mailing addresses to facilitate document acquisition by interested readers.


 

THE COMMERCIAL SHRIMP FISHERY

Shrimp trawling has long been identified as a non-selective fishing activity, with numerous species being vulnerable to the nets. Bycatch in this fishery usually exceeds the catch of shrimp. Since 1990, a comprehensive multi-organizational effort, funded through federal, state and private sources, has addressed shrimp trawl bycatch. Much of the documentation of this effort is in the form of grant final reports, or reports to agencies, and some of it is preliminary. To date, the program has generated information on nearly 6,000 commercial shrimp trawl tows in the southeastern U.S., with a focus on the Gulf of Mexico. In addition, several fishery-independent surveys have been conducted. All totaled, there is a substantial database that can be reviewed for characterization of the catch of the commercial shrimp fishery, and more importantly, much research has now been completed on options to reduce bycatch. Reduction of finfish bycatch, especially for certain heavily fished species such as red snapper, is expected to help rebuild the stock. In the past few years, the shrimp industry has modified its gear configurations and operational techniques; these changes, though not specifically designed to reduce finfish bycatch, achieved that goal as well. For example, the addition of turtle excluder devices (TEDs) in the fishery also reduced the catch of finfish. Several bycatch reductions devices (BRDs) have been tested in the Gulf of Mexico, and some designs have shown good results at substantially reducing finfish while losing only minimal amounts of shrimp.

Shrimp Trawl Bycatch Characterization Studies:

 

Adkins, G. 1993. A comprehensive assessment of bycatch in the Louisiana shrimp fishery. Technical Bulletin No. 42, Louisiana Depart. Wildl. & Fisheries, Marine Fisheries Div., Bourg, Louisiana 70343. Also available as a MARFIN Final Report (Award NA89WC-H-MF006), for the period 1 January 1989 through 31 December 1989.
The study compared the catch rates of offshore and inshore trawlers and wingnet efforts during 108 commercial tows. Brown and white shrimp comprised 60 percent of the catch by number. By weight the average fish/shrimp ratio was 3.2:1 with inshore trawl bycatch higher (3.0 vs. 2.2:1) than offshore trawling; wingnet bycatch was 4.7:1. Although the wingnet catches were higher, the shorter tow times and the handling procedures meant more was released alive than from otter trawling. The study reviews much of the bycatch literature available at the time, and notes the possibilities of reducing bycatch through various methods such as area/time closures, and use of excluder devices.

 

Baltz, D. M. 1993. Patterns in the distribution and abundance of fishes and macroinvertebrates in a Louisiana marsh: shrimp bycatch in the inshore, fishery-independent trawl samples. MARFIN Final Report (Award NA17FF0263-01) by Louisiana State University, Coastal Fisheries Institute, Baton Rouge, Louisiana 70803
Using a 20-year fishery-independent trawl survey of three stations in coastal Louisiana, 141 taxa were identified from over 2,000 tows. Of these taxa, 90 were considered rare, with less than 100 individuals being documented during the entire period; thus only about 50 species occurred with some regularity. Of the 141 taxa, fish comprised 110 species. Two species, the bay anchovy and the Atlantic croaker, comprised 72 percent of the catch by number. The study indicated a stable community structure even with the highly fluctuating environmental conditions that occurred on an annual or longer basis. One disappointing point in this study is a lack of CPUE data by year to indicate trends in relative abundance over such a long time span. This analysis would have suggested the long-term effects of trawling on bycatch species found in inshore Louisiana waters (see Perret et al. 1995; this section for that information).

 

Boylan, J.M., R.P. Webster, H.R. Beatty, and E.L. Wenner. 1990. Results of trawling efforts in the coastal habitat of the South Atlantic Bight. SEAMAP--SA Final Report, FY-1990. Marine Resources Research Div., South Carolina Wildl. & Mar. Resources, Dept., P.O. Box 12559, Charleston, SC 29412.
This study, looking at the South Atlantic Bight, stratified analyses in an inner and outer area by depth. Diversity and abundance was higher in the inner areas. The dominant species overall was spot, occurring in 71 percent of the samples. Atlantic croaker ranked second in frequency of occurrence. The report focused analyses on the mackerels. Spanish mackerel densities were estimated at 1.5 individuals per hectare and included fish from 3-51 cm (mean = 20 cm); length frequencies indicated young-of-the-year and early age-I fish in the catch. King mackerel were estimated at one individual per hectare, and ranged from 4-44 cm (mean = 18 cm), and length frequencies indicated the presence of young-of-the-year and a strong representation of age-I individuals.

 

Chittenden, M.E. Jr., and J.D. McEachran. 1976. Composition, ecology, and dynamics of demersal fish communities on the northwestern Gulf of Mexico continental shelf, with a similar synopsis for the entire Gulf. A Final Report to Texas Sea Grant (TAMU-SG-76-208), Texas A&M University, College Station, TX 77843.
Collections aboard commercial shrimp trawlers during normal working conditions on 4 seasonal trips monitored 21 tows on white shrimp grounds and 39 tows on brown shrimp grounds. 103 species were taken in the 18 kg/tow samples; an additional 58 species were found in the culled catch of the net. The discard to shrimp volume ratio was 11.35:1. The document notes that the authors assumed invertebrates made up 10-20 percent of the discard, thus the fish to shrimp ratio was estimated at 10:1. The document does note that the discard catch in the white shrimp grounds may have been biased due to some large discard catches in June.

 

Coleman, F.C., C.C. Koenig, and W.F. Herinkind. 1992. Annual report: survey of Florida inshore shrimp trawling by-catch and preliminary test of by-catch reduction devices.(Copy received from Gulf of Mexico Fishery Management Council who received it from the Florida Marine Fisheries Commission. This study continued for at least 2 more years; more recent results are probably available from the authors at: Dept. Biological Sciences, Florida St. Univ., Tallahassee, FL 32306).
This document presents the results of the first year's analysis of an ongoing project. It provides a table of the species composition of the catch in 10 different Florida sites, and preliminary results of bycatch reduction devices testing. The tabular material on species composition is not ranked by abundance, although the text does list the most abundant species. Given the preliminary nature of this report, and its limited sample sizes, few conclusions can be drawn; species composition and abundance changed dramatically between seasonal sampling trips, and differed substantially among sites.

 

Fuls, B. 1995. Assessment of composition and magnitude of bycatch associated with the commercial shrimp trawling industry in central lower Texas coastal bays during spring and fall Texas commercial bay-shrimp open seasons. Saltonstall-Kennedy Program Final Report (Award NA37FD0083) by Texas Parks and Wildl. Dept., Austin, TX.
Monitoring three bays in lower Texas - Aransas Bay, Corpus Christi Bay, and lower Laguna Madre - this study reported that bycatch was higher in the spring than in the fall. Bycatch to shrimp ratios were 4:1 to 6.8:1 depending upon season and area. Finfish to shrimp ratios were 1:1 to 5.1:1, again varying by season and area. Bycatch ratios were highest in Corpus Christi Bay and lowest in Laguna Madre. The report also noted that the quantity and composition of the bycatch in this fishery-independent survey was very different from concurrent fishery-dependent surveys.

Bait shrimp bycatch surveys (9.8 m trawl) in Lower Laguna Madre during the spring of 1993 showed that four species (lesser blue crab, Callinectes similis; Atlantic croaker, Micropogonias undulatus; spot, Leiostomus xanthurus; and sand seatrout, Cynoscion arenarius) comprised 62 percent and 43 percent of the mean CPUE in number and weight, respectively. The overall mean CPUE for bycatch was 2,966 individuals/h/net in number and 54.643 kg/h/net in weight. In the fall, five species (sand seatrout, Cynoscion arenarius; lesser blue crab, Callinectes similis; spotfin mojara, Eucinostomus argenteus; hardhead catfish, Arius felis; and Atlantic cutlassfish, Trichiurus lepturus) comprised 65 percent and 53 percent of the mean CPUE in number and weight, respectively. The overall mean CPUE for bycatch organisms was 1,597 individuals/h/net in number and 27.775 kg/h/net in weight.

 

Griffin, W.L., and A.K. Shah. 1995. Estimation of standardized effort in the heterogeneous Gulf of Mexico shrimp fleet. MARFIN final report (Award #NA37FF0053).
Because of concerns about shrimp effort estimates performed by NMFS, this study was conducted to examine alternative estimation techniques. Compared to the current NMFS practice of expanding effort using simple average CPUEs and extrapolating these data for empty cells, the models used in this analysis correct for potential biases associated with blank cells and non-proportional reporting between interviews and landings. Models produced a similarity in estimates to those of NMFS through 1980, but a divergence since that time. The study noted that since 1980 there has been substantial underestimation of "boat" effort and overestimation of "vessel" effort because of non-proportional interviews between these two sectors. The authors estimate that during the period 1965-1993 inshore effort (as nominal days fished) tripled, but boat interviews declined. In contrast offshore effort doubled, but vessel interviews were proportionally too high in the estimates. (See Nance 1992 and 1995 below; this section).

 

Gulf and South Atlantic Fisheries Development Foundation. 1994. Organization and management of a Gulf of Mexico and South Atlantic Ocean fishery bycatch management program (Year II). Saltonstall-Kennedy Grant Program, Final report to the National Marine Fisheries Service (Award NA37FD0032) by the Foundation (Ste. 997, 5401 W. Kennedy, Tampa, FL 33609).
As part of this grant, observers logged 744 days on 63 commercial fishing trips gathering bycatch data for characterization of the catch and evaluation of various BRDs under actual operating conditions. A total of 362 nets were sampled for characterization, and 653 tows compared the catch of a "control" (without a BRD) net to the catch of a BRD-equipped net. The report notes that finfish comprised 67 percent of the catch by weight, while shrimp represented 19 percent; no South Atlantic characterization data were available for analysis. Red snapper were noted to make up less than 1 percent of the catch by weight. BRD testing under this project is reported under the "Bycatch Reduction" section of this report. See also NMFS 1995 under this section for more detailed characterization analyses completed using the entire data set, including foundation and other research efforts.

 

Huner, B., and G. Faulkner. 1995. Energy conservation in the Louisiana shrimp trawling industry. Final report to the Louisiana Dept. Nat. Resources, Energy Div., P.O. Box 44156, Baton Rouge, LA 70804
Focusing on various webbing materials (spectra, knotted, and unknotted polypropylene), this report notes that shrimp catch was similar among webbing types as was finfish catch. Fish to shrimp ratios were 2.2 lb fish to 1 lb of shrimp.

 

Keiser, R.K. Jr. 1976. Species composition, magnitude, and utilization of the incidental catch of the South Carolina shrimp fishery. Technical Report 16, South Carolina Marine Resources Center, Charleston, SC.
A total of 294 tows from 120 trips aboard commercial shrimp boats ranging in length from 35 to 75 feet were sampled in 1974 and 1975. Monthly bycatch to shrimp ratios were 1:1 to 3:1. Fish CPUE ranged from 15 kg/hr to 244 kg/hr while shrimp ranged from 17 to 160 kg/hr. A total of 105 fish species were identified, and only a few species comprised the majority of the catch. Mean total lengths of 25 species ranged from 6.9 to 18.6 cm. Sciaenids made up from 50-80 percent of the catch; spot was the most abundant making up over 30 percent of the yearly catch, followed by star drum at 12 percent, and Atlantic croaker was the fourth most abundant. This report includes numerous tables and figures representing the catch analyses, and provides detailed discussions of the catch and implications of its potential for better utilization.

 

Keiser, R.K. Jr. 1977. The incidental catch from commercial shrimp trawlers of the South Atlantic states. South Carolina Marine Resources Center, Technical Report 26, South Carolina Wildl. & Marine Resources Dept., Charleston, SC 29412.
This report documented, through available literature, the catch in shrimp trawls for the South Atlantic states, North Carolina to Florida. Fish to heads-on shrimp ratios ranged from 1.2:1 to 4:1. For North Carolina, results ranged as high as 100:1, but the average was 4:1. Night time ratios were lower than daytime ratios; not because less fish were caught at night, but because more shrimp (17 percent vs. 13 percent of catch) were taken at night. The two most common species, spot and Atlantic croaker, comprised 63 percent of the finfish catch. For South Carolina, ratios ranged from 2.6:1 in summer to 1.2:1 in fall. Spot and Atlantic croaker were the dominant species, comprising 50 percent of the catch. Bycatch ratios in Georgia were estimated at approximately 2.5:1, and spot, Atlantic croaker, star drum, and bay anchovy were the dominant species. In the Atlantic Florida region, the ratio was approximately 3.8:1. No current estimates of species composition were cited.

 

Martinez, E.X., and J.M. Nance. 1993. Trawling Bycatch in the Galveston Bay System. The Galveston Bay National Estuary Program Publication GBNEP-34. NMFS/SEFSC, Galveston, Texas.
The characterization study, performed by the National Marine Fishery Service (NMFS) Galveston Laboratory, was conducted in three phases: 1) a review of historical bycatch studies, 2) initiation of new data collection efforts on commercial vessels and 3) a comparison of new data collected with fishery-independent surveys of the Texas Parks and Wildlife Department. Three historical studies regarding bycatch in Galveston Bay were identified and reviewed. Matlock (1982) analyzed the catch of gulf and southern flounder Paralichthys albigutta and P. lethostigma, respectively) in 34 tows from a commercial shrimp vessel during April-November 1978. He concluded bycatch of flounder was lower in Galveston Bay than in other Texas bay systems. Lamkin (1984) reviewed bycatch in tows sampled from one bait shrimp vessel in lower and West Galveston Bay during July 1981-June 1982. He identified 56 bycatch species (52 finfish species) from 62 samples (34 trips); bycatch averaged 27.2 percent of total catch weight (range = 17-42 percent). Lamkin observed that five species accounted for about 71 percent of the bycatch by number and 65 percent of bycatch biomass. These species included Atlantic croaker, sand seatrout, blue crab, spot and gulf menhaden. Bessette (1985) accompanied six different bait shrimpers throughout five areas of Galveston Bay during May-November 1984. In 107 tows sampled, Bessette identified 66 species of finfish and eight invertebrates. Bycatch comprised 3-99 percent of total catch by weight with an average of 65 percent. Bessette observed 4.1 kg of fish captured for each kg of shrimp landed.

New data collection was initiated in 1992 by NMFS. A total of 296 samples were collected during March-November 1992 and 85 finfish species and 49 invertebrates were identified. Overall, bycatch species comprised 38 percent of the catch by number and averaged 71 percent of total catch by weight. Nine species (of 134 total) accounted for 80 percent of the bycatch by number and 79 percent by weight. These included gulf menhaden, Atlantic croaker, spot, cutlassfish, sand seatrout, bay anchovy, Atlantic brief squid, hardhead catfish and blue crab. Gulf menhaden, Atlantic croaker and sand seatrout were the only species of commercial or recreational value which were captured in great numbers.

 

Nance, J.M. 1992. Estimation of effort in the Gulf of Mexico shrimp fishery. NOAA Tech. Mem., NMFS-SEFSC-300.
Given the size of the shrimp fleet in the Gulf of Mexico, including inshore, nearshore, and offshore vessels, actual documentation of effort is impossible. Boats and vessels are interviewed