Age, Growth, and Mortality of the Little Skate off the Northeast Coast of the United States

Abstract

Abstract Age, growth, mortality, and yield per recruit of the little skate Raja erinacea in the Georges Bank-Delaware Bay region were investigated from trawl-survey data collected during 1968–1978. Eight age groups were observed in the population. The parameters of the von Bertalanffy growth equation are asymptotic length L∞ = 52.73 cm; growth coefficient K = 0.352; and hypothetical age at zero length t0 = -0.449 years. The length-weight relationship for both sexes combined over seasons is log10W = -2.641 + 3.229 log10L, where length L is in centimeters and weight W is in grams. Estimates of total instantaneous mortality rates Z for fully recruited ages (age 5 and older) ranged from 0.54 to 1.76 between 1968 and 1978. Natural-mortality values M ranged from 0.4 to 0.5; fishing-mortality values F ranged from 0.14 to 1.36, depending on the value of M assumed. Received May 13, 1983 Accepted March 21, 1984