Abstract

Recruitment of early life-stages of many species into shallow inshore estuarine habitats is responsible for high fisheries production. Estuarine habitats are also subject to wide fluctuations in physical conditions which can influence recruitment success through effects on the growth and survival of early life stages. In order to examine field-growth responses of juvenile white trout with respect to continuous variation in physical habitat conditions, we related modal shifts in length distributions of recruiting cohorts to continuous changes in abiotic variables. Weekly shoreline collections of juvenile white trout were made over a five week period between 12 May and 16 June, 1997 at Marsh Point in Mississippi Sound. Using a DataSonde IV®, hourly changes in water temperature, salinity, dissolved oxygen, turbidity, depth, and pH were also recorded throughout the five week recruitment period. Weekly modal shifts in length distributions of white trout reflected proportional changes in length ranging ftom 0.20 to 0.54; and changes in weekly growth were strongly tied to changes in weekly mean water temperature (P = 0.013). Other abiotic variables were unrelated to water temperature on the weekly scale. However, abiotic variables may show different interrelationships depending on the temporal scale on which they are considered, suggesting that their effects on recruitment processes need to be analyzed on the same temporal scale on which recruitment is measured. Comparison of these findings and previous work showed that within-site-temporal variability and between-site-spatial variability in growth rates can be driven by different abiotic variables. Whereas within-site variability in growth of juvenile white trout was primarily driven by water temperature, former work with juvenile mullet in the same system suggested that inter-site variability in growth was primarily determined by salinity

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