Allyn G. Johnson

Age and Growth of Yellowtail Snapper from South Florida

Abstract Age and growth of yellowtail snapper Ocyurus chrysurus from south Florida were determined from otolith cross-sections. The oldest fish was 14 years old (443-mm fork length). Mean back-calculated fork lengths of 807 fish ranged from 136 mm at the end of year 1 to 429 mm at the end of year 14. The von Bertalanffy equation for 802 yellowtail snapper aged 10 or less was Lt = 450.9[1 - e-0.279(t+0.355)], where L = fork length (mm) and t = years. The length-weight relationship was W = 6.13 × 10-5L2.76, where W = weight (g).

Estimate of genetic polymorphism and heterozygosity in three species of rockfish (genus Sebastes).

Abstract 1. 1. An estimate of the genetic polymorphism and average hetorozygosity in three species of rockfish, Sebastes alutus, S. caurinus, and S. elongatus was made using differences in electrophoretic mobility of proteins on starch gel. 2. 2. In S. alutus two of twenty-five loci; in S. caurinus, one of twenty-five loci; and in S. elongatus, two of twenty-four loci were polymorphic. 3. 3. This yields estimates of 8,4 and 8 per cent of all polymorphic for the average species population and values of 3·8, 1·8 and 3·3 per cent for the proportion of the genome heterozygous per individual in the average population.

Electrophoretic variants of aspartate aminotransferase of the bay mussel, Mytilus edulis (Linnaeus, 1758)

Abstract 1. 1. Thirteen phenotypes of aspartate aminotransferase were detected in extracts of Mytilus edulis by starch gel electrophoresis. 2. 2. Evidence is presented of a six-allele system in this species.

Chlorine-Induced Mortality of Eggs and Larvae of Spotted Seatrout (Cynoscion nebulosus)

Abstract The acute lethal effects of sodium hypochlorite, chloramine, and 5-chlorouracil on eggs and larvae of spotted seatrout, Cynoscion nebulosus, are presented. Forty-eight-h median tolerance limits (TLm) for the various toxicants and age classes (2-h-old eggs, 10-h eggs, and 1-h posthatch larvae) were, respectively: sodium hypochlorite—0.21 ± 0.01, 0.21 ± 0.01, 0.17 ± 0.28 ppm; chloramine—14.14 ± 1.13, 0.57 ± 0.28, 5.75 ± 3.01 ppm; 5-chlorouracil-8.91 ± 1.03, > 100, 79.43 ± 44.97 ppm. The 48-h TLm varied depending on toxicant and age class.

Phosphoglucomutase polymorphism in pacific ocean perch, Sebastodes alutus.

1. n1. Three phenotypes of phosphoglucomutase were found in muscle extracts of Pacific ocean perch (Sebastodes alutus) by starch gel electrophoresis. n n2. n2. Evidence for nonrandom distribution of phenotypes with regard to depth at which samples were taken, sex and alleles of α-glycerophosphate dehydrogenase is presented.