Growth and mortality in successive cohorts of fish larvae within an estuarine nursery

Abstract

In mummichog Fundulus heteroclitus variation in mean daily specific rates of growth (G = 0.027-0.143) and mortality (Z = 0.007-0.118) within and among cohorts was associated with the tidal cycle. Growth rates was positively associated and mortality rate negatively associated with the duration of tidal flooding experienced by groups of fish larvae. Tidal flooding may have affected growth and survival by controlling the renewal rate of prey resources in intertidal aquatic microhabitats where the fish larvae are normally found. Overall high survival (up to 90% after 2 wk) of larvae in experimental cohorts was attributed to the exclusion of predators from field enclosures. Successive cohorts of larvae were not nutritionally independent and use of the nursery habitat by a prior cohort usually had a negative effect on survival of larvae in the next cohort. -from Author