干旱区生态环境知识资源中心

Finfish composition and seasonal abundance was studied in the world largest arid mangrove ecosystem of the Indus Delta, Pakistan. Sampling was done from February 2010 to July 2011 in a narrow creek with thick mangrove forest and in a wide creek with sporadic patches of mangrove forest along its banks. The sampling revealed 84 fish species, corresponding to 2,274 individuals in 60 genera and 29 families, weighing a total of 217kg. A minimum of 8 species were recorded in December 2010 while a maximum of 32 species were recorded in April 2010 (average 21 +/- 5.8). The most speciose families were the Mugilidae (9) followed bythe Sciaenidae (8) and the Ariidae (7), the remaining 26 families being represented by 1-5 species. The average sizes of 28 dominant species in the collection ranged from 76.9 to 284.6mm (SL), consisting mostly of juveniles. Relative abundance (%) and relative biomass (%) of species was between 0.04 and 9.1 and 0.01-12.14, respectively. The Pearson correlation of 0.52 (r(2) 0.27) was observed among the environmental parameters and found significant between temperature and dissolved oxygen (p<0.03). The canonical correspondence analysis showed strong relationships of different salinity and temperature ranges with the diversity and biomass composition. The species occurrence frequency was 69% in the wide creek and 31% in the narrow creek. We conclude that the Indus Delta is a highly productive zone in terms of fish diversity, providing ideal habitat for a nursery rather than a fishing ground and propose it to be a marine protected area (MPA).