Szedlmayer and Conti: Nursery habitat, growths rates, and seasonality of age-0 Lut/anus campechanus 



629 



4). Station 4 growth rates were not estimated be- 

 cause of low catch rates. 



Discussion 



Age-0 red snapper used inner shelf habitat at first 

 settlement, and an area 13 km south of Mobile 

 Bay (station 1) held particularly high numbers. 

 No other study has reported such high CPUEs of 

 age-0 red snapper. Many factors could contribute 

 to this important nursery habitat at station 1. 

 Temperature, dissolved oxygen, salinity, and 

 depths, showed little difference among stations, 

 but one potential aspect that may provide avenues 

 for future studies is substrate type. The substrate 

 in this area may be highly suitable, e.g. relic shell 

 beds (Schroeder et al., 1995) with fine sand sedi- 

 ments, and there is a general shift from shell-sand- 

 mud to "clean" sand east of Mobile Bay.' where 

 few fish were collected. Age-0 red snapper may be 

 selecting such shell habitats. For example, age-0 

 red snapper showed a preference for shell over 

 sand substrata in laboratory studies (Szedlmayer 

 and Howe, 1997 land a preference for almost any 

 small relief structure (e.g. shells) in relation to flat 

 sand substrata in natural habitats (Workman and 

 Foster, 1994). Shells were observed in trawl col- 

 lections at station 1 and not apparent in trawl 

 samples at other stations. However, we were un- 



' Hummell, R. L. 1998. Geological survey of Alabama, 

 Tuscaloosa. AL. Personal commun. 



a. 

 o 



25 

 20 

 15 



10 - 

 5 - 



1994 CPUE 

 all stations 



160 n 

 140 

 120 

 100 



80 



60 



40 



20 



-1* •r- 1 ] ; - I - I* r 



Jun Jul Aug Sep Oct Nov Dec Jan 



Month 



Figure 3 



Mean CPUE lnumber/10-min towi of age-0 red snapper, 

 Liitjaniif: compechaniis. by date from the northeast Gulf of 

 Mexico. Each point represents mean CPUE for that date. Er- 

 ror bars are standard errors. Different letters show signifi- 

 cant differences both within and between years (ANOVA; 

 Waller-Duncan test; P<0.05). 



