Stock Structure Analysis of Indian Mackerel, Rastrelliger kanagurta (Cuvier, 1816) along the Indian Coast

The Indian mackerel, Rastrelliger kanagurta (Cuvier, 1816) forms a commercially important single species pelagic fishery in India, especially along the west coast. Therefore, information on the stock structure of this resource is of paramount importance for adopting proper management measures. A truss network was constructed by interconnecting 16 landmarks to form a total of 36 truss measurements, based on 337 samples collected from five populations representing off the Veraval and Mumbai coasts in northwest zone, Goa, Mangalore and Cochin in southwest zone. The common factor analysis (CFA) of truss network indicated body depth related traits loading heavily on first factor, shape related traits belonging to finlet area in the caudal portion on second factor and traits in middle portion of thebody on third factor. The analysis revealed that, Indian mackerel exists as a single stock along the west coast of India, but the reduced intermixing of populations of distant locations has induced some morphological differentiation, which is progressive along the coast and in significant magnitude between very distant populations.