Biological survey on small pelagic fishes (sardine & anchovy) stocks in coastal waters of Hormuzgan province (Qeshm Island & Bandar Lengeh) with emphasis on Sea surface temperature, Plankton distribution and Chlorophyll-a

Investigation on small pelagic fishes in the north of the Persian Gulf (Qeshm Island and Bandar Lengeh) coastal waters during October 2006 to September 2008, illustrated that 6 sardine and 2 anchovy species were locally existed. Sind sardinella (Sardinella sindensis) and Buccaneer anchovy (Encrasicholina punctifer) were dominated in this area. The peak of sexual maturity for Sind sardinella and Buccaneer anchovy occurred in spring and summer respectively. Reproduction period for Sind sardinella was from the middle of winter to late spring, and Buccaneer anchovy encompassed reproduction capacity all the year. The female: male ratio was calculated 1:0.7 and 1:0.9 for Sind sardinella, 1:1.27 and 1:1 for Buccaneer anchovy in Qeshm Island and Bandar lengeh sequentially. The mean of absolute fecundity were estimated 16234 and 16168 for Sind sardinella, 1277 and 1141 for Buccaneer anchovy in Qeshm Island and Bandar Lengeh respectively. LM50 and LC50 were calculated and the results showed both species mainly caught before length of maturity, and the mass populations have not sufficient opportunity to reproduction. Both species were planktonivore, theirs food prefect mainly consisted of copepods, naplius and bivalves. Vacuity index indicated both spices were semi-voracious appetite fishes. Based on calculated length-weight relationships in S. sindensis and E. punctifer, they have isometric growth. Growth parameters were estimated, the results illustrated that they were growth fast and short live species, which suggested S. sardinella and E. punctifer have 3 and 2 years maximum life span respectively. The recruitment pattern indicated double recruitment peaks per year in both species. Annually, four cohorts were distinguished in Sind sardinella and 3 cohorts in Buccaneer anchovy. Total mortality (Z), natural mortality (M) and fishing mortality (F) were estimated in both species, and the values of exploitation ratio (0.78 & 0.74) in Sind sardinella and (0.72 & 0.41) in Buccaneer anchovy were reasonable for current fishing effort due their short life span. Analysis of the results showed that CPUE in sardine and anchovy affected by reproduction and feeding processes. Results showed significant correlation between sardine CPUE and Sardine GaSI (P<0.05, r= 0.499), similarly between anchovy CPUE and anchovy GSI (P<0.05, r=-0.635). Further, significant correlation between sea surface temperature with sardine CPUE (P<0.05, r=0.493), phytoplankton distribution (P<0.01, r=0.560), anchovy GSI (P<0.05, r=0.526), anchovy GaSI (P<0.05, r=-0.500) and chlorophyll a (P<0.01, r=0.780). Phytoplankton distribution with sardine GSI (P<0.05, r=0.453), zooplankton distribution with anchovy GSI (P<0.05, r=0.671), and chlorophyll with sardine GSI (P<0.01, r=0.761) have significant correlation.

Iranian Fisheries Science Research Institute

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