TY - JOUR
T1 - Catch and Bycatch
T2 - The Qualitative Effects of Fisheries on Population Vital Rates of Atlantic Croaker
AU - Diamond, Sandra L.
AU - Crowder, Larry B.
AU - Cowell, Lindsay G.
N1 - Funding Information:
We thank Joshua Bennett, Bob Colura, Pat Geer, Bill Hettler, Joan Holt, Jim Johnson, Rene Laba-dens, T. Lankford, Jim Murray, Larry McEachron, Rick Monohan, Steve Nixon, Butch Pellegrin, Steve Ross, Frank Schwartz, Peter Sheridan, David Sutherland, Peter Thomas, Katy West, and Chris Wilson for providing unpublished data and helpful information. We thank Chris Dumas and John Quinlan for their initial legwork on this project. Jim Rice, Joe Hightower, Ken Pollock, and Doug Vaughan provided helpful reviews of the manuscript. This research was supported by University of North Carolina Sea Grant award R/MRD-27, a predoctoral fellowship from the National Science Foundation, the J. Frances Allen Scholarship from the American Fisheries Society, and the Joseph L. Fisher Award from Resources for the Future.
PY - 1999/11
Y1 - 1999/11
N2 - Bycatch in shrimp trawl fisheries can make up 60–80% of the catch by weight. Finfish taken incidentally in shrimp trawls include juveniles of species that are valuable in directed fisheries as adults. Atlantic croaker Micropogonias undulatus is commonly caught as bycatch in shrimp trawls and has also been a target species in both the Gulf of Mexico (the Gulf) and the South and Middle Atlantic bights (the Atlantic). The catch of Atlantic croaker, including bycatch, has historically been at least three times higher in the Gulf than in the Atlantic. Gulf fisheries, including the directed industrial fishery, have primarily harvested juvenile fish. In contrast, the most intensive fisheries in the Atlantic have targeted adult fish. We hypothesized that population-level effects of exploitation differ qualitatively between fisheries that take primarily juveniles and fisheries that target adults, even in the face of bycatch of juveniles. We compiled data on Atlantic croaker fisheries, life history parameters, and population abundance in the Gulf and the Atlantic and followed changes in these variables over time. In the Gulf, long-term intensive fishing of Atlantic croaker juveniles has caused severe declines in abundance since the 1930s but little change in adult life history parameters: Large fish remain common, the size distribution has been relatively stable, and the size at maturity has not changed. In the Atlantic, however, targeted fishing of adults has caused both declines in abundance and major changes in adult life history parameters: Size at maturity, common sizes (the range in length of about 90% of the individuals in a length frequency distribution), maximum length, and modal lengths of adult fish have been reduced. Bycatch of juveniles may have contributed to the changes in Atlantic adult life history parameters by reducing the number of fish that survive to adulthood, making the population more sensitive to adult fishing. We explore several hypotheses to explain why juvenile fisheries (Gulf) would have smaller effects on life history than targeted adult fisheries (Atlantic). If our observations are correct, reductions in bycatch legislated by the U.S. Magnuson–Stevens Act should allow Atlantic croaker to increase in abundance in the Gulf (but have little effect on size distributions) and to increase both in abundance and in adult size in the Atlantic.
AB - Bycatch in shrimp trawl fisheries can make up 60–80% of the catch by weight. Finfish taken incidentally in shrimp trawls include juveniles of species that are valuable in directed fisheries as adults. Atlantic croaker Micropogonias undulatus is commonly caught as bycatch in shrimp trawls and has also been a target species in both the Gulf of Mexico (the Gulf) and the South and Middle Atlantic bights (the Atlantic). The catch of Atlantic croaker, including bycatch, has historically been at least three times higher in the Gulf than in the Atlantic. Gulf fisheries, including the directed industrial fishery, have primarily harvested juvenile fish. In contrast, the most intensive fisheries in the Atlantic have targeted adult fish. We hypothesized that population-level effects of exploitation differ qualitatively between fisheries that take primarily juveniles and fisheries that target adults, even in the face of bycatch of juveniles. We compiled data on Atlantic croaker fisheries, life history parameters, and population abundance in the Gulf and the Atlantic and followed changes in these variables over time. In the Gulf, long-term intensive fishing of Atlantic croaker juveniles has caused severe declines in abundance since the 1930s but little change in adult life history parameters: Large fish remain common, the size distribution has been relatively stable, and the size at maturity has not changed. In the Atlantic, however, targeted fishing of adults has caused both declines in abundance and major changes in adult life history parameters: Size at maturity, common sizes (the range in length of about 90% of the individuals in a length frequency distribution), maximum length, and modal lengths of adult fish have been reduced. Bycatch of juveniles may have contributed to the changes in Atlantic adult life history parameters by reducing the number of fish that survive to adulthood, making the population more sensitive to adult fishing. We explore several hypotheses to explain why juvenile fisheries (Gulf) would have smaller effects on life history than targeted adult fisheries (Atlantic). If our observations are correct, reductions in bycatch legislated by the U.S. Magnuson–Stevens Act should allow Atlantic croaker to increase in abundance in the Gulf (but have little effect on size distributions) and to increase both in abundance and in adult size in the Atlantic.
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U2 - 10.1577/1548-8659(1999)128<1085:CABTQE>2.0.CO;2
DO - 10.1577/1548-8659(1999)128<1085:CABTQE>2.0.CO;2
M3 - Article
AN - SCOPUS:0033388066
SN - 0002-8487
VL - 128
SP - 1085
EP - 1105
JO - Transactions of the American Fisheries Society
JF - Transactions of the American Fisheries Society
IS - 6
ER -