NOTE Kotas et al.: Incidental capture of Caretta caretta and Dermochelys conacea by the pelagic longline fishery 



397 



not a reliable indicator of maturity or breeding status for 

 sea turtles (Miller, 1997). 



Along the southern coast of Brazil (between latitudes 

 23°S and 33°S), loggerhead sea turtles stranded or in- 

 cidentally captured in fishing gear with CCLs as small 

 as 32.5 cm have been observed (Projeto TAMAR 4 ), but 

 usually loggerhead sea turtles found in that region have 

 CCLs greater than 50 cm, most commonly in the range of 

 60-90 cm (Pinedo et al., 1998; Bugoni et al., 2001; Projeto 

 TAMAR 4 ). Loggerhead sea turtles have also been found in 

 Uruguay and Argentina (Frazier, 1984; Fallabrino et al., 

 2000). Their CCLs in those countries have been reported 

 to be in the approximate range of 50-115 cm (Frazier, 

 1984). The loggerhead sea turtles reported here have 

 an average CCL smaller than that usually observed for 

 loggerhead sea turtles stranded or captured in southern 

 Brazil, Uruguay, and Argentina, although most of the 

 turtles (45 out of 54, or 83%) had CCLs equal to or greater 

 than 50 cm, that is, they were within the size range for 

 that region. 



Cumulative evidence obtained from genetic and size- 

 distribution data around oceanic basins, as well as tag 

 returns, shows that the ontogenetic development of log- 

 gerhead sea turtles involves a pelagic juvenile stage (Carr, 

 1987; Musick and Limpus, 1997; Bolten et al., 1998). Trans- 

 oceanic developmental migrations establishing a link be- 

 tween juveniles in feeding grounds and hatchlings from 

 nesting beaches on opposite sides of the ocean basin have 

 been demonstrated through genetic analysis for the North 

 Atlantic and North Pacific (Bowenet al., 1995; Bolten et al., 

 1998). It has been suggested that a similar pattern may be 

 expected for the South Atlantic (Bolten et al., 1998), where 

 loggerhead sea turtles nest in Brazil and possibly in Africa 

 (Marcovaldi and Laurent, 1996; Fretey, 2001). The inciden- 

 tal captures reported in our study, indicating the use of the 

 pelagic environment by juvenile loggerhead sea turtles in 

 the South Atlantic, support the hypothesis of transoceanic 

 developmental migrations for those turtles in that ocean. 

 Future genetic analysis of turtles incidentally captured in 

 the South Atlantic would help to clarify their natal origin. 



For leatherback sea turtles, there are important nesting 

 grounds in the Atlantic, mainly in French Guiana and Su- 

 riname in South America, and Gabon and Congo in Africa 

 (Spotila et al., 1996; Fretey, 2001). Leatherback sea turtles 

 are known to travel long distances from their nesting 

 beaches into pelagic waters (Goff et al., 1994; Morreale et 

 al., 1996; Eckert and Sarti, 1997; Eckert, 1998). Satellite 

 telemetry data indicate that leatherback sea turtles nest- 

 ing in eastern South Africa can enter the South Atlantic 

 (Hughes et al., 1998; Hughes 5 ). In the southwestern Atlan- 

 tic, leatherback sea turtles have been observed or captured 

 in Brazil, Uruguay, and Argentina (Frazier, 1984; Pinedo 

 et al., 1998; Achaval et al., 2000; Fallabrino et al., 2000; 

 Bugoni etal., 2001). 



Some measure of the significance of the three trips re- 

 ported in the present study in terms of the potential for 

 turtle capture and mortality in the South Atlantic longline 

 fishery can be obtained by looking at information concern- 

 ing the total fishing effort in the study area. In 1999, the 

 Brazilian longline fleet consisted of 70 longliners (42 Bra- 

 zilian and 28 leased foreign vessels); among them, 33 ves- 

 sels were operating out of ports in southern Brazil, in the 

 states of Sao Paulo, Santa Catarina, and Rio Grande do 

 Sul. In that year, the total number of hooks of that long- 

 line fleet (both Brazilian and leased vessels) amounted to 

 13,598,260 hooks (ICCAT 6 ). However, the southwestern 

 Atlantic is fished not only by Brazil-based longliners, but 

 also by longliners from Uruguay, Chile, Japan, Taiwan, and 

 Spain (Folsom, 1997; Weidner and Arocha, 1999; Weidner 

 et al., 1999). According to ICCAT's (International Commis- 

 sion for the Conservation of Atlantic Tunas) CATDIS data 

 set (ICCAT) 7 longliners operating during 1995-97 in the 

 area delineated by the present study (latitudes 25°S and 

 35°S and longitude 35°W, or eight ICCAT 5x5° statistical 

 blocks. Fig. 1) had an average annual catch of tunas and 

 swordfishes of 6885 metric tons (t) (the total hold capacity 

 of the vessels on the three trips reported in this study was 

 130 t). However, due to unreported landings by vessels 

 flying flags of convenience (FAO, 2001; FAO 8 ) and other 

 sources, the estimate obtained from ICCAT data should be 

 considered a minimum estimate of the total annual tuna 

 and swordfish catch ( ICCAT 9 ). Furthermore, because North 

 Atlantic stocks of swordfishes and some species of tuna are 

 considered overfished (NMFS 10 ), quota or closure regula- 

 tions (or both) in the North Atlantic may be driving longline 

 fleets to the South Atlantic, increasing the risk of incidental 

 capture of sea turtles there. 



In Brazil, sea turtle capture is prohibited by federal 

 legislation (Marcovaldi and Marcovaldi, 1999), and mea- 

 sures have been taken to address the problem of inci- 

 dental capture by longlines and other kinds of fishing 



4 Projeto TAMAR. 2000. Unpubl. data. Rua Antonio 

 Athanasio 273, Ubatuba, SP 11680-000, Brazil. 



5 Hughes, G. R. 2002. Personal commun. Ezemvelo KZN 

 Wildlife, P O Box 13053, Cascades 3202, South Africa. 



6 ICCAT (International Commission for the Conservation of 

 Atlantic Tunas). 2001. National report of Brazil. Report 

 for biennial period, 2000-2001, part I (2000), vol. 1, English 

 version, p. 312-315. Calle Corazon de Maria, 8, 28002 

 Madrid, Spain. 



7 ICCAT (International Commission for the Conservation of 

 Atlantic Tunas). 2002. CATDIS dataset. Calle Corazon de 

 Maria, 8, 28002 Madrid, Spain. (Available from http://www. 

 iccat.org.] 



s FAO (Food and Agriculture Organization of the United 

 Nations). 2001. International plan of action to prevent, 

 deter and eliminate illegal, unreported and unregulated fish- 

 ing, 24 p. FAO, Rome. (Available from http://www.fao.org/ 

 docrep/003/yl224e/yl224e00.htm.] 



9 ICCAT (International Commission for the Conservation of 

 Atlantic Tunas). 1999. Detailed report for swordfish, 

 ICCAT SCRS swordfish stock assessment session (Madrid, 

 Spain, September 27 to October 4, 1999), 176 p. Calle 

 Corazon de Maria, 8, 28002 Madrid. Spain. 



10 NMFS (National Marine Fisheries Service). 2000. 2000 

 stock assessment and fishery evaluation for Atlantic highly 

 migratory species, 150 p. U.S. Dep. Commer., NOAA, NMFS. 

 Highly Migratory Species Management Division, 1315 East- 

 West Highway, Silver Spring, MD 20910. 



