Date of Award

Summer 1993

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Biological Sciences

Program/Concentration

Biology

Committee Director

Cynthia M. Jones

Committee Member

Mark J. Butler

Committee Member

Ray S. Birdsong

Call Number for Print

Special Collections LD4331.B46 N59

Abstract

Sagittal otoliths were used to determine the age and growth of 605 larval and juvenile Atlantic croaker, Micropogonias undulatus, collected in the Middle Atlantic Bight (MAB) and estuarine waters of Virginia. A Laird-Gompertz model (r2 = 0.95) was used to describe the growth of croaker up to 65 mm standard length (SL) and 142 days (t): S1(t) = 2.657 Exp {4.656 [1-Exp (-0.008lt)]}; SL(t) = standard length at day t. Generally, croaker collected inshore were larger and older than those collected offshore, indicating estuarine immigration from offshore spawning grounds. Back-calculated hatch-dates indicated spawning over an 8- month period from 05 July 1987 to 10 February 1988 with 82% of spawning occurring from August to October. Regression analysis indicated that early-spawned larvae (before October) grew more than 41 % faster than late-spawned larvae (after September). Lapillar and sagittal otoliths were compared with light microscopy and found that lapillar otoliths underestimated age and were inadequate as a surrogate to sagittal otoliths in age determination. A fourth order polynomial best described (r2 = 0.99) the relationship between SL and sagittal otolith maximum diameter (OMD). Contrary to the literature for other species, faster growing croaker had more than 12% larger otoliths than same size slower growing fish.

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DOI

10.25777/dys4-bk98

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