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Analysis of Catch per Unit of Effort and Length Composition in the South Carolina Commercial Handline Fishery, 1976‐1982
Author(s) -
Low R. A.,
Ulrich G. F.,
Barans C. A.,
Oakley D. A.
Publication year - 1985
Publication title -
north american journal of fisheries management
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.587
H-Index - 72
eISSN - 1548-8675
pISSN - 0275-5947
DOI - 10.1577/1548-8659(1985)5<340:aocpuo>2.0.co;2
Subject(s) - pagrus , fishery , demersal zone , epinephelus , catch per unit effort , sparidae , biology , zoology , grouper , geography , fishing , fish <actinopterygii>
Catch‐per‐unit‐of‐effort (CPUE) data for catch/trip, catch/boat‐day, and catch/reel‐day for major demersal species groups were analyzed by season, boat length, and number of crew. Seasonality was a major component of variability in CPUE. There was no significant difference in catch/reel‐day by boat length for any species group, while catch/boat‐day increased with crew size for all species combined, groupers (Mycteroperca spp.), and vermilion snapper (Rhomboplites aurorubens). Correlations between catch/trip and catch/reel‐day were good (r = 0.80‐0.85) for red porgy (Pagrus pagrus), groupers, and red snapper (Lutjanus campechauus). Time trends in seasonally adjusted quarterly mean trip production were negative for all species groups, with significant correlations for red porgy, groupers, and red snapper. Estimates of annual maximum sustainable physical yield (MSY) calculated using a Schaefer model and parameter values from the negative regressions of catch/trip on the number of trips were approximately 144,200 kg for red porgy, 190,000 kg for groupers and 32,000 kg for red snapper in waters from Savannah, Georgia to Cape Fear, North Carolina. For each species, the estimated total (recreational plus commercial) harvest has exceeded MSY in recent years. Time trends in mean total length from 1976 to 1982 showed declines ranging from 8% for gag (Mycteroperca microlepis) to 15% for red porgy and red snapper. Increases in percentage of the catch below the critical size ranged from 2% (gag) to 32% (red porgy). Except for red porgy, the current mean size of all species is well above the applicable critical size, even though MSY apparently is being exceeded. Because the majority of the fish being caught are above the critical size, this raises questions about the applicability of the current management strategy based on yield per recruit.