Age, growth and mortality of weakfish, Cynoscion regalis, in North Carolina with a discussion on population dynamics / by Jess H. Hawkins, III.
| Author/creator | Hawkins, Jess H. author. |
| Other author | O'Rear, Charles W., degree supervisor. |
| Other author | East Carolina University. Department of Biology. |
| Format | Theses and dissertations |
| Production | 1988. |
| Description | v, 86 leaves : illustrations, maps ; 28 cm |
| Supplemental Content | Access via ScholarShip |
| Subjects |
| Summary | Age, growth and mortality of 1,354 weakfish, Cynoscion regalis, captured in North Carolina waters during 1982 and 1983 by pound net, long haul seine, sink gill net and pelagic trawl fisheries were examined. Scales formed a single yearly annulus between May and Noyember, with peak formation occurring in June and July. Ages ranged from 0 to 11 and sizes ranged from 60 to 865 mm fork length (FL). The von Bertalanffy growth equation was Lt = 917(1-e-0.203(t-0.170)). Growth parameters were most similar to those of weakfish in northern latitudes. Mean back-calculated lengths were not significantly different north and south of Bluff Shoal, Pamlico Sound. Back-calculated lengths north and south of Cape Hatteras were significantly different for ages 2 to 4, but not significantly different for ages 1, 5 and 6. The length-weight relationship (r = 0.98) was W(g) = 8.32 x 10⁻⁹ FL(mm)̇³̇⁰³.. Weakfish 200 to 300 mm FL and ages 1 to 2 dominated long haul seine and pound net catches, while weakfish 200 to 300 mm FL and ages 0 to 1 dominated the trawl landings. The sink gill net fishery primarily harvested weakfish 300 to 400 mm FL and ages 1 tc ?. Weakfish size and age compositions of the oceanic fisheries were similar to those noted in northern waters and indicated considerable mixing of weakfish off North Carolina north of Cape Lookout. Instantaneous annual mortality rates, determined from catch curves, were relatively high in the estuarine fisheries (pound net = 0.81, haul seine = 0.85) when compared to those of the oceanic fisheries (trawl = 0.56, gill net = 0.45). Optimum harvest for all fisheries terms of yield-per-recruit occurred at ages 3 to 5. |
| General note | Submitted to the faculty of the Department of Biology. |
| General note | Advisor: Charles W. O'Rear, Jr. |
| Dissertation note | M.S. East Carolina University 1988 |
| Bibliography note | Includes bibliographical references (leaves 80-86). |
| Genre/form | Academic theses. |
| Genre/form | Academic theses. |
| Genre/form | Thèses et écrits académiques. |
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|---|---|---|---|---|
| Joyner | University Archives | ASK AT SPECIAL COLLECTIONS DESK | ✔ Available | Request Material |
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