Inter-annual variations of selectedudoceanographic parameters and itsudrelation to fishery of small pelagicsudoff Kochi, southwest coast of India

摘要

The availability as well as abundance of selected smalludpelagics along Kerala coast (south west coast of India) wasudhighly variable during the past three decades. During theudperiod 1980-2012 there have been several periods ofudabundance as well as population crashes in the oil sardineudfishery. The present study revealed that the occurrence of lowudsea level during the month of May implies either early winduddriven upwelling or early intensification of equator-wardudcoastal current and consequent upsloping of isopycnals. Theudoccurrence of low sea level (6857) as early as in May andudupwelled water in August with low dissolved oxygen (0.68udml l-1) with low sea water temperature (24˚C) at the bottomudat 10 m depth, off Kochi was found to affect the sardineudfishery in the year 1994, when the landing at Kochi was onlyud15 t. Mean sea level was found to be a sign of upwelling andudthe real time observations of dissolved oxygen indicated wideudvariations during the upwelling period.