Population dynamics of two morphotypes ofgreen tiger shrimp Penaeus semisulcatus de Haan, 1844 in the northern coast of Iran

Abstract

Population biology of two morphotypes of Penaeus semisulcatus de Haan, 1844 was investigated from January to July 2017 and January 2018 to December 2019 in the Hormozgan coastal waters off Iran. Growth in both sexes was negative allometric. The sex ratio (M:F) was significantly different in terms of month and length classes in both the morphotypes. Year round the female population dominated in the banded morphotype while males in the non-banded morphotype. Size-wise, the male population was more in smaller classes and females in larger classes for both the morphotypes. The spawning peak of shrimps occurred in spring season (from March to May) and in winter-spring (from January to May) for banded and non-banded morphotypes, respectively. The Lm50% for banded and non-banded shrimp was estimated at a carapace length of 37.86 and 43.43 mm, respectively. The K and CL∞ in banded shrimp were 1.6 y-1 and 46 mm for males and 1.8 y-1 and 57 mm for females and in non-banded shrimps were 1.7 y-1 and 55 mm and 2.1 Y-1 and 69 mm for males and females, respectively. The total mortality (Z) and fishing mortality (F) estimated in males were more than in females. The evidence showed that these are probably two different species in the region. Keywords: Growth and mortality, Oman Sea, Penaeus semisulcatus, Persian Gulf, Reproductive biology, Size structure