Advection, dispersion and mortality of a patch of southern bluefin tuna larvae Thunnus maccoyii in the East Indian Ocean

Abstract

Reports on measurements of a large, high density patch of larvae in the East Indian Ocean made in January-February 1987. The patch at the start of sampling consisted of a distinct cohort of larvae 7 to 8 d old. Diffusion in subsequent 2 d intervals was slow (1.02-1.5 m2s-1) but within the bounds observed for patch scales in the order of a few kilometres wide. Intensifying SW winds were opposed by advection with a SW drift of c6 cm s-1. Instantaneous mortality (Z) was 0.66 d-1 (daily survival rate of 52%). -from Authors