394 



Fishery Bulletin 102(2) 



t — i — i — i — i — i — vr—r 

 Atlantic Ocean 



J. 



10 N 



40 - 



50 S - 



Ascension 



St. Helena 



Tristan da Cunha 



South Georgia 



N 



t 



j i i i i i i i i 



80 W 



20 



10 



10 



20 E 



Figure 1 



Fishing locations. Numbers 1, 2, and 3 indicate locations of the first, second, and third 

 longline trips respectively; for each location, one or more sets were performed. Circled 

 numbers indicate international waters outside the 200-mile Brazilian exclusive economic 

 zone. The rectangular ocean area is limited by latitudes 25°S and 35°S and longitude 35°W. 

 The fishing location farthest to the east is about 1320 km (713 nautical miles) from Itajai, 

 State of Santa Catarina, Brazil, the home port of the fishing vessels. 



seabed in this area ranged from the continental shelf 

 border to abyssal plains, including submarine elevations 

 (e.g., Rio Grande). Operation depths, ranging from 170 to 

 4000 m, were obtained from nautical charts. 



The first and second trips were aboard the Yamaya III, 

 a 20.7-m, 325-hp engine, 30-t hold capacity, 10-crew long- 

 liner, and the third trip was aboard the Basco, a 24.4-m, 

 330-hp engine, 70-t hold capacity, 11-crew longliner. 

 The vessels targeted swordfishes, sharks (mainly blue 

 sharks, Prionace glauca) and tunas (Thunnus albacares, 

 T. alalunga and T. obesus). Their fishing gear was the 

 U.S. -style monofilament nylon longline, with 200- 

 300 m sections between buoys, and each section contained 

 four to five gangions set 40-60 m apart. Buoy dropper 

 length ranged between 10 and 20 m, and gangion length 

 ranged between 13 and 20 m. Each non-offset "J" hook 

 (Swordfish 9/0) was baited with Argentine shortfin squid 

 (Illex argentinus) and had a yellow chemical light stick 

 hung over it. The average number of hooks per set was 

 1030, 992, and 950 on the first, second, and third trips, 

 respectively. 



On the first and second trips, the mainline was set off the 

 stern by means of a line shooter so that a marked catenary 

 was formed between buoys, allowing the hooks to operate 

 at a greater depth. In this case, the maximum hook depth 

 may have reached more than 40 m. On the third trip, the 

 vessel Basco did not use a line shooter, and thus the hook 



depth for that trip may have been shallower. The longline 

 gear was set around 5:30 PM, and was retrieved early in 

 the morning. The average soak time was 7 h 30 min. For 

 each set, the date, time, geographical position, number of 

 hooks, and sea surface temperature were recorded. The 

 species and condition (i.e., if the animal was alive or dead) 

 of captured turtles were recorded; specimens with no ap- 

 parent movement were considered dead. 



Incidentally captured loggerhead turtles were taken 

 aboard and hooks and lines were then removed. Whenever 

 possible curved carapace length (CCL) and width were 

 measured, and the turtles were double tagged (inconel 

 tags style 681, National Band and Tag Co., Newport, 

 KY), according to Projeto TAMAR's (Projeto Tartaruga 

 Marinha, the Brazilian sea turtle conservation program) 

 standard methods (Marcovaldi and Laurent, 1996). In 

 some cases, it was not possible to bring loggerhead sea 

 turtles on board the fishing vessel and, because of their 

 great size, no leatherback sea turtles were brought on 

 board. On these occasions, the turtles were pulled close to 

 the boat and the gangions were then cut to free the turtles 

 with the hooks still attached to them; however the length 

 of the line remaining on the turtle was not recorded. None 

 of these turtles was measured or tagged, although some of 

 the leatherback sea turtles were filmed on video. No addi- 

 tional data and measurements, other than those presented 

 in this study, were obtained. 



