Serafy, Joseph E. and Diaz, Guillermo A. and Prince, Eric D. and Orbesen, Eric S. and Legault, Christopher M.
Atlantic Blue Marlin, Makaira nigricans, and White Marlin, Tetrapterus albidus, Bycatch of the Japanese Pelagic Longline Fishery, 1960–2000.
Marine Fisheries Review, 66(2),
ABSTRACT—Since the late 1950’s, a multi-national longline fishery has operated throughout the Atlantic Ocean to supply the growing global demand for tunas (Scombridae) and swordfish, Xiphias gladius. Two species caught as bycatch include Atlantic blue marlin, Makaira nigricans, and white
marlin, Tetrapterus albidus, referred to in this paper as “Atlantic marlin.” Pelagic longlining has consistently been the principal source of adult mortality for both species, which are currently depleted and have been so for more than two decades. In this paper, we examined aspects of the Atlantic marlin bycatch of the Japanese pelagic
longline fishery from 1960 to 2000. Temporal and spatial patterns in effort, target catch (species combined), marlin bycatch, marlin catch-per-unit-effort (nominal CPUE), and
ratios of marlin bycatch to target catch (B: T ratios) were analyzed. An objective was to reveal changes, if any, in marlin bycatch associated with the fishery’s target species
“switch” (ca. 1980–87) from mostly surface-associated tunas to mostly the deeper-dwelling bigeye tuna, Thunnus obesus. The highest values of all variables examined occurred
during the 1960’s and then fell by the second half of that decade. Since 1970, mean levels of fishing effort, target fish catches, and blue marlin landings have increased significantly, while blue marlin CPUE and B:T ratios have remained relatively stable. Concurrently, white marlin landings, CPUE, and B:T ratios have all declined. While results suggest the fishery’s target species change may
have been a factor in lowering white marlin bycatch, the same cannot be said for blue marlin. Relative increases in blue marlin B:T ratios off the northeastern coast of South
America and in the wider eastern Atlantic are cause for concern, as are continuing trends of CPUE decline for white marlin in this data set as well as others.
||Atlantic Blue Marlin, Makaira nigricans, and White Marlin, Tetrapterus albidus, Bycatch of the Japanese Pelagic Longline Fishery, 1960–2000
|Serafy, Joseph E. |
|Diaz, Guillermo A. |
|Prince, Eric D. |
|Orbesen, Eric S. |
|Legault, Christopher M. |
|Journal or Publication Title:
||Marine Fisheries Review
||United States National Marine Fisheries Service
Patti M. Marraro
||15 Aug 2012 17:50
||15 Aug 2012 17:51
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