6th World , Fisheries Congress, Edinburgh, Scotland (UK), United Kingdom, 1 - 04 May 2012, pp.162
Knowledge on the abundance and distribution of fish eggs and larvae is a key technique to aid the identification of important spawning and nursery grounds. This knowledge is vital in understanding fluctuations in fish population dynamics. In order to ascertain and define active spawning grounds for bluefin tuna a larval survey was conducted in June 2004. Here we describe the distribution and abundance of larvae from bluefin tuna (Thunnus thynnus) and other teleost species.
The ichthyoplankton surveys were conducted from the Turkish trawler "Emicaoglu" between 5th and 18th of June 2004. Surveys were restricted to the northern Levantine Sea. A total of 104 sub-surface horizontal tows were performed. For horizontal surface tows a Bongo 90cm, of 1mm mesh size was used and for oblique tows a Bongo 60cm diameter of 250μm mesh size. The duration of all tows was fixed at 10 minutes. All ichthyoplankon samples were stored in 5% neutralised formalin.
In total, 7654 fish larvae belonging to 13 different taxa and 7 families were captured. A total of 53 taxonomic groups were identified, 36 to species level and the remainder to genera or family level.
The most abundant species captured was the Electric lantern fish (Electrona risso) making up 39% of the total larvae captured. Commercially valuable species such as Bluefin tuna (1.5%), European pilchard (Sardina pilchardus, 23%), European anchovy (Engraulis encrasicolus, 9.7%) were all represented in the samples collected. The distributions of bluefin tuna, sardine and anchovy were mainly concentrated on shelf areas of the northern Levantine Sea. These findings provide valuable evidence regarding important spawning and nursery grounds in the Cilician Basin and Mersin Bay, Turkey.