Fish Population Dynamic and Stock Assessment

3.2.7. Growth Co-efficient

The growth parameter ‘K’ is related to the metabolic rate of the fish. Pelagic species are often more active than demersal species and have a higher ‘K’.  The tropical fishes have higher ‘K’ values compared to coldwater fishes.

The curvature parameter ‘K’ values are more related to ‘M’ values. In short lived species, particularly tropical fishes, ‘K’ is directly proportional to ‘M’. The ‘M/K’ is inversely related to L_m/L $$_{\infty}$$ and is also an index of reproductive stress. This value is found to be high for fish exhibiting post spawning death phenomena. (Lm is the minimum length at first maturity)

Temperate fishes live long compared to tropical species. The Natural mortality is high for short lived species.

Lm/L$$\infty$$ is an index of reproductive stress.

K is directly correlated with natural mortality.

Lm/L$$\infty$$ is inversely related to K and L$$\infty$$.

(This is because, larger the asymptotic size, ‘K’ will be less and the rate of growth is high in short lived species, most of the tropical species have short life span compared to temperate species).