Some Biological Aspects of the Sharpnose Mullet Liza saliens (Risso, 1810) in Gorgan Bay-Miankaleh Wildlife Refuge (the Southeast Caspian Sea)

摘要

The present study investigated age, growth and reproduction of the sharpnose mullet L. saliens by regular monthly collection throughout one year from April 2002 to March 2003 in Gorgan Bay (the southeast Caspian Sea). Based on scale readings, the maximum ages of the population observed were 6(+) years for males and 7(+) years for females. Both sexes grew allometrically (b=2.478 males; b=2.545 females) and rapidly during first year, achieving more than 40% of their growth. The von Bertalanffy growthfunctions were L-1=30.415 (l-e(-0.275(t+0.645))) for males and L-1=34.832(l-e(-0.211(t+1.009))) for females. Monthly examination of condition factor showed that similar condition cycle is evident in both sexes, peaking in May (1. 135 for males; and 1. 136 for females). Overall sex ratio was balanced, but males were predominant in smaller sizes, and females in larger sizes, The GSI indicated that reproduction of sharpnose mullet in Gorgan Bay occurred around May-July, with the highest average value of 1.996 for males and of 5.973 for females in June. Absolute fecundity varied from a minimum of 135014 for age 3(+) to a maximum of 389790 eggs for age 7(+). The absolute fecundity to fish size (length and weight) and age were positively correlated.