geographical variation in substrate composition was 

 beyond the scope of this project, low relief areas off 

 Georgia generally do not display large variations in 

 substrate composition (Henry footnote 2). Evidence 

 to substantiate this point is presented in Table 1, as 

 substrate samples from areas with similar loran coor- 

 dinates typically possessed similar substrate com- 

 positions. 



Third, while a seasonal component to catch rate 

 has been observed off New Jersey (Grimes et al. 

 1980), our data for this analysis do not strongly 

 display this trend (Table 1). 



In addition, because the area fished did not display 

 evidence of significant prior exploitation, our results 

 were not affected by the potentially confounding in- 

 fluence of commercial fishing. 



In conclusion, approximately three-quarters of the 

 variation in tilefish catch rate off Georgia could be 

 attributed to variation in a single physicochemical 

 factor: the silt-clay fraction of the substrate. At pres- 

 ent, however, the generality of this relationship is 

 unknown with respect to other geographical areas or 

 locations with different exploitation histories. In 

 addition, temperature also has been shown to affect 

 the distribution of tilefish off the northeastern 

 United States (Grimes et al. 1980). It is likely that 

 within areas possessing suitable thermal regimes, 

 substrate composition is a major factor affecting tile- 

 fish abundance. While a variety of associations be- 

 tween fish abundance and physicochemical factors 

 have previously been identified (Moyle and Cech 

 1982), to our knowledge, none approach the intensity 

 of the relationship described herein. We believe that 

 identification of this relationship will aid fisheries 

 biologists in the identification and demographic 

 quantification of tilefish stocks as well as the location 

 of new fishing grounds. 



ACKNOWLEDGMENTS 



We appreciate the assistance of the captains and 

 crews of both the Georgia Bulldog and the Delaware 

 II, without whom this work would not have been 

 possible. The following individuals either reviewed 

 the manuscript or aided in other aspects of the study: 

 K. Able, C. Barans, P. Bartlett, E. Chin, D. Beau- 

 mariage, D. Daniels, D. Erickson, M. Freeman, S. 

 Floyd, C. Grimes, E. Guthertz, D. Harrington, V. 

 Henry, J. Hill, B. Low, L. Parker, L. Pittman, M. 

 Rawson, D. Stouder, G. Ulrich, and C. Wenner. 

 Facilities and logistic support for this study were 

 graciously provided by the University of Georgia 

 Marine Extension Service at Brunswick. We also 

 wish to acknowledge the continued support of our 



research by the Georgia Sea Grant College Program 

 under contract #NA80AA-D-00091. The manuscript 

 was ably typed by Bonnie Fancher. 



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