Fisheries Recruitment in the Northcentral Gulf of Mexico: Can Important Geographic Sources of Juvenile Nursery Habitat Be Determined Using Otolith Microchemistry?

The specific objectives of this two year study are to:
1) collect young juvenile spotted seatrout from nine potential nursery areas extending from Grand Bay, Alabama to the Louisiana marshes east of the Mississippi River;
2) analyze the elemental composition and stable isotope ratios (C and O) of sagittal otoliths from juveniles in order to determine if the areas where these fish were collected can be distinguished;
3) determine how precisely juveniles can be categorized based on previously determined spatial patterns of otolith microchemistry;
4) examine age 1+ spotted seatrout from throughout the study region acquired during year 2 in order to analyze the elemental "fingerprint" of the inner portion (formed during the juvenile stage) of their otoliths; and
5) compare the chemical "fingerprint" of the inner portion of adult otoliths with juvenile otoliths processed during the previous year to determine where the adults grew up as juveniles.

This research will not only define the relative importance of different habitats source areas that are critical for the survival of juvenile spotted seatrout, but will also further develop techniques that can subsequently be applied to many other estuarine species. Distinguishing the relative importance of different estuarine habitat source areas for selected species is of particular concern because of rapid coastal development and the threat of continued habitat degradation along the northcentral Gulf Coast. Results of this research will certainly impact future decisions regarding watershed conservation and management in this region.