The demersal fish composition and catch per unit effort of mini bottom trawl at the coast of Demak Regency Central Java

Naliyana Fitriya,Eko Setyobudi,Nahlah Alfiatuunisa,Suwarman Partsuwiryo,E.S Kartamihardja,E Setyobudi,P.G Sasmita,Alimuddin Alimuddin,N Hubert,T Peristiwady,C.P.H Simanjuntak,D.F Mokodongan,S.B Andi Omar,S.M Bergmann,Djumanto Djumanto,A Collins

doi:10.1051/e3sconf/202132203006

Abstract

Demak is a coastal area on the North Coast of Java with a large enough potential for demersal fish resources. This research aimed to determine the composition, the length and weight distribution, and catch per unit effort (CPUE) of demersal fish caught using mini bottom trawl at the north coast of Demak Regency. The research was carried out in October-December 2020 by observation of ten trips of mini bottom trawl fishing. Each fish captured was then grouped by type, identified, and measured its length and weight. The result showed that 38 species consist of 31 fishes, four mollusks, and three crustaceans. The fish captured dominated by pony fish (Leiognathus equulus) as much as 31.23% and largehead hairtail (Trichiurus lepturus) of 23.52%. The catch per unit effort (CPUE) average of mini bottom trawl was 44.77 kg/trip. Mainly fish (more than 95%) caught in small size compared it’s the maximum attainable length (L-max), with all the weight ranges from 0.3 to 520 g and more than 98% sized 0.3-80 g. Mini bottom trawl catches many types of fish and small size; therefore, mini bottom trawl is classified as a type of fishing gear with a very low selectivity level.

Highlights

Fisheries are renewable resources; the exploitation should be conducted responsibly based on their carrying capacity
The fish captured dominated by ponyfish (Leiognathus equulus) as much as 31.23% and largehead hairtail (Trichiurus lepturus) of 23.52%
The composition of catch using mini bottom trawl as many as 38 species consists of 31 fish, four mollusks, and three crustaceans

Summary

Introduction

Fisheries are renewable resources; the exploitation should be conducted responsibly based on their carrying capacity. Fisheries exploitation without regard to its carrying capacity and fish regeneration will lead to the depletion of the potential of fisheries resources [1]. According to the Ministerial Decree of Maritime and Fisheries Number 50 of 2017, the potential source of demersal fish in the Java Sea is 657,525 tons/year. It has been exploited as much as 0.83 with a number of catches allowed (JTB) by 526,020 tons/year. This value indicates that this area has been fully exploited; fish capture activities should be controlled appropriately

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Discussion

Conclusion