Figure 24. Grunt school over coral reef during daytine. At night these schools will 

 disperse over seagrass beds and adjacent sand flats to feed. 



the fishes of Alligator Reef with brief 

 notes on their ecology, while Davis (1967) 

 described the pomadasyids found on this 

 reef and their ecology. 



Little is known about the ecology of 

 these nocturnal coral reef fishes while on 

 the feeding ground. These fishes poten- 

 tially can range far fron their diurnal 

 resting sites. Lutjanus griseus and 

 Haemulon flayol ineatun range as far as 

 1.6 km (1 ni) from Alligator Reef (Starck 

 and Davis 1966). Haemulon plumeri and H^. 

 flavol ineatun typically migrate distances 

 of 300 m (984 ft) to greater than 1 km 

 (0.6 mi) over the grass beds in Tague Bay, 

 St. Croix (Ogden and Ehrlich 1977; Ogden 

 and Zienan 1977). Tagged H_. plumeri were 

 repeatedly captured on the same reef and 

 when transplanted exhibited a tendency to 

 home (Springer and McErloan 1962a). Some 

 H^. plumeri and H. flavol ineatum success- 

 fully home to original patch reefs over 



distances as great as 2.7 km (1.7 mi) in 

 the U.S. Virgin Islands (Ogden and Ehrlich 

 1977). 



It is interesting to speculate on the 

 possible role that habitat partitioning 

 plays in reducing competition for food 

 over the feeding ground. Competition is 

 important in structuring other fish com- 

 munities, such as Centrachidae (Werner and 

 Hall 1977), Embiotocidae (Hixon 1980) and 

 Scorpaenidae (Larson 1980). Starck and 

 Davis (1966) reported that 11 of 13 pom- 

 adasyids found in durnal resting schools 

 on Alligator Reef disperse at night to 

 feed. The lighter colored grunts (seven 

 species) move off the reef and generally 

 distribute themselves along a sand flat- 

 grass bed back reef continuum. Snappers 

 (Lutjanidae) follow a similar pattern with 

 l^. griseus and U synagris moving into 

 mixed sand, grass and rubble back reef 

 habitat. The nocturnal distribution of 



76 



