Determining standards far the mesh size of the beach seine used by Iranian fishing cooperatives.

Being the largest lake of the world and as a land – locked water body, The Caspian Sea accommodates one of the most precious fishery stocks of the world which are annually caught by beach seines. These Net are the single authorized meanQ of harvesting bony &ish stocks )n coartal Caspian se` waters along The Gilan, Mazandaran & Golestan provinces .The first use of beac ˇ seine dates babk to 1900 - and which does not seem to have been designed on any partic5lar technical or tactical cofsiderations. Due to lack of technically sound design of the fishing nets and their low sElective fishing capabilities for catching phe target species there have, unfortujately been large amount of by – catch substandard fish to such an extent that the non – standaRd Fish caught has accounted for nearly of total landings in re#ent year. The average length od Kutum, the dominant fish species caught By fishing cooperatives using beach seine was 55 cm 80 years ago which has been plummeted down to 37cm in 2007.Therefore it is noticed that during the past 80 decades a sum of 15,000,000 kg of various bony fishes have been caught as by – catch. These fishes include R. frisii kutum, mugil auratus, mugil saliens, Cyprinus carpio ,R. rutilus casPicus, ViMba persa , chalchalburnts chalcOdes , Aspius taeniatus , Alosa sp, Barbus Brachycephalus caspius , @bramis brama , lucioperca lucioperca , Salmo trutta caspius, Silurus glanis, Esox lucius, & sturgeons. There have, so far, been no scientific basis or standards far the design & construction of fishing gears that could upgrade the utilization of commercially important fish stocks in the Iranian side of the Caspian sea It is needless to point out that a scientific any practical approach for the management of fishery resources calls for a revision in the principle of construction & design of active fishing gears as well as a change in the fishing grand. During the past century, a 20 time’s revision in the design a construction of fishing gears had been required. In this research, it has been attempted to make the necessary modification in the beach seine proportionate with the natural conditions of southern coast of Caspian Sea based on the biological data on a Rutilus frisii kutum and mullet stocks. Thus through the changes in the mesh size of the beach seine nets, it is possible to improve the Q-amount of standard sized fish and reduction of the non – standard sited ones.

Beach seine, mesh size, Iran, Rutilus frisii kutum, mullet, Caspian Sea