Spotted seatrout (Family Sciaenidae) growth as an indicator of estuarine conditions in San Carlos Bay, Florida

Life history characters of the spotted seatrout (Cynoscion nebulosus) have tremendous potential to discern trends in environmental conditions within and among estuaries. The species is widely distributed (i.e., from North Carolina to Mexico), is both commercially and recreationally important, and rarely leaves its home estuary. Thus, the estuarine conditions to which a population was subjected while growing could affect changes in its life history features such as growth. About 400 spotted seatrout were collected from April through July 2003 from the San Carlos Bay area of the southern portion of Charlotte Harbor in southwest Florida. Otolith sections were examined with enhanced imagery to facilitate recording age and annulus increments from the otolith. There was a significant relationship between otolith radius and fork length that differed between sexes. A comparison of back-calculated size at Age 1 for four year classes (1999–2002) indicated that there were significant differences in growth between year classes. Initial time-series analysis indicated the potential effects of seagrass density and salinity on fish growth. Salinity conditions are artificially manipulated in this estuary and this action may be responsible for the differences in growth rates observed for both males and females among year classes.