Fish Population Dynamic and Stock Assessment

2.1.4. Fish growth in tropical and temperate waters

Fishes in temperate waters live long compared to those in warmer regions. The growth coefficient, natural mortality are generally higher in tropical waters compared to temperate waters. Fish tend to mature according to a fixed portion to their asymptotic size (L _¥ ). Larger the asymptotic size, larger is also the size at first maturity. Hence for a given family of fish Lm/L _¥ is a constant ratio (Cushing, 1965). The asymptotic length and minimum maturity are generally higher in fishes of temperate waters. Because these two parameters are at higher side, it could be said Lm/L _¥ is inversely related to M/K. This is due to the inverse relation between K and L _¥ .

In elasmobranch fishes of tropical waters, unlike teleosts grow slowly, live long and attain very large size. In general, elasmobranchs have long life with slow growth rate; the reproductive rate is also high with low reproductive stress.