Fish Morphology and Barrier Trap Bar Spacing in Lagoon Fisheries along the Aegean Coast of Turkey

Year 2018, Volume: 1 Issue: 2, 49 - 56, 30.05.2018

Zafer Tosunoğlu , Ravda Önem Karakuzu Gökhan Gökçe , M. Hakan Kaykaç

Abstract

The most important fishing rule implemented in Turkish
lagoon fishery is distance between the reeds (stick) of the barrier traps
should not be less than 3 cm. Based on this arrangement, usually 3 cm bar
spacing reeds and sometimes 3 cm square mesh wires are used in lagoon barrier
traps. The body shape of fish may be the most important factor necessary to
understand the consequences of changes in barrier trap selectivity. For this
reason, data were collected to determine the relevant dimensions of fish body
in relation to openness of a barrier trap of coastal lagoons along the Aegean
coast of Turkey in 2013. As Minimum Landing Size (MLS) was built on Total
Length (TL) basis, regression analyses were carried out to find out the
relationships between the TL and the other measured dimensions (width and
height) of the fish using least-square regression. Morphometric measurements of
fish species caught in barrier traps show a great variation. While all Common sole
individuals pass from the 3 distance with its width, all Flathead grey mullet
and European sea bass individuals retained behind the sticks of the barrier
trap. All Gilthead sea bream individuals under 25 cm TL pass the distance.
However, many Golden grey mullet and European eel individuals retain at the
barrier traps with theirs width. The implemented 3 cm bar spacing in
Turkish lagoon barrier traps is thought to be suitable only for sea bass with a
1% reduction. However, the bar spacing is not suitable for Sea bream, Common
sole, European eel due to commercial loss and for Flat head grey mullet and
Golden grey mullet capturing small individuals below their MLS. For this
reason, a graded barrier system with different bar spaces or regulation
according to the biology of the fish species and migration seasons can benefit
sustainable lagoon fishery. In this respect, the continuously changing distance
paradox in barrier traps will be overtaken in Turkey.

Keywords

Coastal lagoon, barrier trap, openness, fish morphology

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