Growth rate of tropical demersal fishes

Abstract

A revlew of avadable information showed that length at age of tropical demersal fishes is a function of the specific maximum length (LM), and that for species with similar L,, differences in growth rates are direct consequences of their feeding habits. Fishes that depend on fish as main food source develop below average relative growth rates, while those that are either opportunistic or browser feeders grow faster. Invertebrate-eating fish grow in an intermediate pattern. These generali-zations were derived from 53 age determinations of 37 tropical demersal fish species whose L, ranged from 13 to 270 cm. During their first year, fishes with L, of (51 cm are able to grow up to % of their L , ; those with LM from 51 cm to 100 cm attain almost '/z of it, and those with larger LM are able to grow only up to near % of their length Limit. Relative length at age (R,,) is significantly and inversely correlated with LM, and when corrected with factors that describe the feeding regime of each species, the calculated R,, using the theoretical equations for ages 1 to 8 yr old can be used to stratify fish length samples into age groups. The corrected theoretical equations were used to evaluate the age structure of 6 exploited demersal fish populations of Campeche Bank (Mexico), providing total mortality rates not statistically different from those simultaneously obtained with direct age determinations. Further, there was an inverse and significant correlation between the growth deceleration coefficient (k) and the asymptotic length (L,) of the reviewed species.