Distribution,abundance and population ecology of ashtoret lunaris (Forskel,1775) and matuta planipes fabricius,1798 from the sonmiani bay (Lagoon),Pakistan

Matuta planipes and ashtoret lunaris were collected as a part of by catch of gillnet deployed for shrimps from april 2005 to march 2007 in sonmiani bay waters (miani hor lagoon). m. planipes was found abundantly in sep. 2005,nov.-dec. 2005 and dec. 2006 (93.3%,94.7%,92.3% and 87 % respectively). a. lunaris was found in abundance during may 2005 (85.7%) and aug. 2005 (81.8%). male specimens of both species (m. planipes: χ2 = 245.4,p < 0.005) and (a. lunaris: χ2 = 99.4,p<0.005) were signifcantly more than females throughout the study period. there was a signifcant difference in size of male and female crabs within sexes; (m. planipes: t =-4.93,p < 0.005) and (a. lunaris: t =-2.92,p<0.005). various morphometrical relationships were demonstrated that the males of m. planipes and a. lunaris were larger in size and heavier than females (4.34g ± 0.9g; 14.86 ± 6.8g and 3.87g ± 0.6g; 11.66 g ± 5.4 g) respectively. there was a negative allometry for both male and females of m. planipes and a. lunaris for length and weight relationship. the estimated carapace size at onset of sexual maturity was 3.2 cm and 3.3 cm for males and females of a. lunaris whereas,males and females of m. planipes had sexual maturity carapace size 3.1 cm and 3.2 cm in lagoon waters of sonmiani bay. © 2017 zoological society of pakistan.