Wells and Rooker: Distribution, age, and growth of young-of-the-year Senolo dumerili 



551 



data were presented. Because of the lack of studies 

 investigating growth of YOY S. dumerili, we compared 

 our estimates to those in Sakakura and Tsukamoto's 

 (1997) study of YOY S. quinqueradiata where growth 

 rates were estimated at 1.3 mm/d. Average temperature 

 in their study was 21.2°C, which was considerably lower 

 than the average during our study (28.6°C) and may 

 account for their slower growth rates. 



Variation in growth of S. dumerili was observed and 

 rates were significantly higher in the offshore zone 

 and greater for the late season cohort. Differences in 

 water temperature may be partly responsible for ob- 

 served differences in growth. Planes et al. (1999) sug- 

 gested that spatial differences in growth of juvenile 

 sparid fishes were a result of water temperature and 

 currents. The proximity between zones in this study 

 may have masked differences in hydrography; however, 

 temperatures were higher in the offshore zone (29.8°C, 

 CV=0.03) than in the inshore zone (28.7°C, CV=0.04), 

 and warmer temperatures were likely contributing to 

 faster growth rates in offshore waters. Intra-annual 

 (cohort-specific) growth patterns indicated that the late- 

 season cohort had the fastest growth. Similar to trends 

 between zones, temperature was lowest for the slowest 

 growing cohort (early season) and highest for the fast- 

 est growing cohort (late season). Although temperature 

 may affect early life growth of S. dumerili, differences 

 in growth may be attributed to other factors such as 

 prey availability and predator activity (Houde, 1987; 

 Paperno et al., 2000; Plaganyi et al., 2000). Moreover, 

 a clear distinction exists in the size classes of YOY S. 

 dumerili in comparisons of growth rates and these dif- 

 ferences likely contribute to the observed results. 



The mortality rate of YOY S. dumerili associated with 

 pelagic Sargassum was estimated at 0.45 %/d for fishes 



2001 



mm 



^ w n n 



Age class (days) 



Figure 6 



Age-frequency distribution of S. dumerili collected in 

 association with Sargassum in 2000 and 2001. 



collected in 2000. These findings are well below similar 

 studies investigating mortality of YOY individuals. Nelson 

 (1998) calculated a mortality estimate of 2.1-2.3^/d for 

 pinfish in three different bay areas in the eastern Gulf of 

 Mexico. In addition, Deegan (1990) estimated YOY men- 

 haden mortality between 1.7 and 2.1'S/d in the northern 



