340 



Fishery Bulletin 100(2) 



two BRDs, the FFE and the EMF (Fig. 3) in three sizes 

 of otter trawls in Tampa Bay during October-Decem- 

 ber 1996 (fall) and February-April 1997 (winter). 

 Both BRDs are standard devices that have been rec- 

 ommended by NMFS, are used by the commercial 

 fishing sector, and have been extensively tested in off- 

 shore and inshore waters throughout the southeast- 

 ern United States (Murray et al., 1992: Watson et al., 

 1993; Rogers et al, 1997; Coleman et al." Christian et 

 al.'-'; McKenna and Monaghan''*). 



The otter trawl dimensions were as follows: 1) 14-m 

 net: mouth circumference = 14.0 m, float-line length = 

 6.3 m, lead-line length = 6.9 m; 2) 17-m net: mouth 

 circumference = 17.0 m, float-line length = 6.9 m, lead- 

 line length = 7.8 m; 3) 20-m net: mouth circumfer- 

 ence = 20.0 m, float-line length = 8.1 m, lead-line 

 length = 9.4 m. The nets were of appropriate lengths 

 to conform to the 45-m- total-mesh-area rule. Net pe- 

 rimeters were chosen after consultation with commer- 

 cial shrimpers and personnel from the NMFS Labora- 

 tory Hai-vesting Section, Pascagoula, Mississippi. All 

 net bodies were constructed of no. 9 twine and had a 

 stretch-mesh size of 3.8 cm; the tailbag was constructed of 

 no. 18 twine and had a stretch-mesh size of 3.2 cm. The 

 FFE was constructed of 13-mm-diameter stainless steel 

 rods. It had an overall length of 30 cm and a 15-cm x 15-cm 

 opening to allow fish to escape. The FFE was mounted at 

 the top center of the tailbag at 70'7( of the distance be- 

 tween the tie-off rings and the beginning of the codend 

 (Watson et al., 1993; Christian et al.'- ), creating an area of 

 reduced water flow directly behind the FFE, which would 

 allow fish to escape. The EMF had an overall length of 



'■'' Christian, P. A., D. L. Harrington, D. R. Amos, R. G. Overman, 

 L. G. Parker, and J. B. Rivers. 199.3. Final report on the re- 

 duction of finfish capture in south Atlantic shrimp trawls. Final 

 report to National Marine Fisheries Service (award NA27FD 

 0070-01). Univ. Georgia, 71.5 Bay Street. Brunswick, GA 

 31520, 83 p. 



" McKenna, S. A., and J. P Monaghan Jr 1993. Gear develop- 

 ment to reduce bycatch in the North Carolina trawl fisheries. 

 Completion report to Gulf and South Atlantic Fisheries Develop- 

 ment Foundation (cooperative agreement NA90AA-H-SK052I. 

 North Carolina Div Mar. Fish.. 3441 Ai-endell Street. Morehead 

 City NC 28557, 79 p. 



Lead line 



Coden(j 



Bag tie 



Figure 2 



Components of a semiballoon otter trawl equipped with a super 

 shooter turtle excluder device (TED). The TED is required in all 

 shrimp nets in Florida. 



Figure 1 



Tampa Bay, Florida. Hatched region shows sampling area. 



121 cm and a circumference of 120 meshes; it consisted 

 of a web funnel (3.5-cm stretch-mesh size) surrounded by 

 a larger-mesh "escape" section (21-cm stretch-mesh size) 

 held open by a plastic-coated hoop. One side of the funnel 

 was extended to form a lead panel that created an area of 

 reduced water flow on the back side of the funnel, similar 

 to that created by the FFE. 



To conform to federal regulations, each net was equipped 

 with a turtle excluder device (TED) placed near the mouth 

 of the tailbag (Fig. 2). The standard super-shooter TED 

 consisted of a metal grid of seven aluminum bars with a 

 9-cm interbar distance; the grid was set at a 45° angle to 

 direct turtles downward toward the escape opening (Wat- 

 son et al., 1993). Sewn in front of the TED was a section 

 of webbing (3.2-cm stretch-mesh) that formed an acceler- 

 ator funnel (Fig. 3A), which increased the velocity of wa- 

 ter and entrained organisms both through the TED and 

 into the net tailbag. The tailbag section and the combined 

 TED and accelerator-funnel section could be zipped to any 

 trawl body, regardless of size. The zipper ensured random 

 pairing of trawl body and tailbag and enabled the experi- 

 mental and control nets to be easily exchanged through- 

 out the project. The BRDs and TEDs used during 

 this project were approved by the NMFS Labora- 

 tory Harvesting Section, Pascagoula, Mississippi. 



Both types of BRDs were tested in each net size. 

 For each net size, one net of a matched pair was 

 equipped with either the FFE or the EMF and 

 served as the experimental net and the other, unal- 

 tered net served as the control. In the experimen- 

 tal net, the FFE or EMF was installed behind the 

 TED-accelerator funnel section. The net with the 

 BRD was deployed off a randomly chosen side of 

 the boat and its paired control net was deployed 

 simultaneously off the other side in a double-rig 

 trawl towed from 3.5-m outriggers. Each net was 

 spread by two 123-cm x 62-cm wooden trawl doors 

 linked bv a tickler chain. 



