LENGTH-WEIGHT RELATIONSHIPS IN THREE MARKETABLE SIZED MACKEREL FISH SPECIES COLLECTED FROM KARACHI FISH HARBOUR, PAKISTAN.
Fish is a source of highly nutritive protein and play an important role in food chain. Total 177 specimen of Rastrelliger kanagurta, 119 specimen of Scomberomorus commerson, and 108 specimen of Scomberomorus guttatus were collected from Karachi fish harbour during August, 2006 to December, 2008. The maximum mean length (24.17+0.28 cm) and mean weight (134.6+2.583 g) of Rastrelliger kanagurta were recorded during spring 2007-2008. In Scomberomorus commerson highest mean length (48.8+0.22 cm) and weight mean (726.15 +8.48 g) were measured during winter 2006-2007 and 2007-2008 respectively. The highest mean length of Scomberomorus guttatus (51.22+0.11 cm) and weight mean (701.9 + 10.09) were recorded in during spring (2006-2007). Our result showed that Rastrelliger kanagurta fish estimated negative allometric growth because b values less then 3. Fish Scomberomorus commerson, Scomberomorus guttatus, showed positive and negative allometric growth because b value shows were larger b<3 or smaller b>3.