Catch per unit effort (CPUE) and catch composition of small scale fisheries in Gökova Bay

Abstract

The gillnet and longline catch compositions and catch-per-unit effort (CPUE) of small scale fishing vessels in Gökova Bay were evaluated through studies carried between July, 2009 and May, 2011. A total of 16 studies (5 for gillnets, 11 for longlines) was made with the vessels and gears of commercial fishers. To calculate the fishing effort (f), CPUE and daily catch quantity were calculated through 131 samplings (72 times for gillnets, 59 for longlines) with random selection at landing spots. When both gears were evaluated in combination, a total of 31 species was detected; 27 species from Teleostei group, 1 from Crustacea, 2 from Cephalapoda and 1 from Chondrichthyes. Gillnets caught 19 species while long lines caught 16 species. Among the products landed, gillnets caught mostly Pagellus erythrinus, Trachurus mediterraneus and Scomber japonicus, while longlines caught Sparus aurata, Dicentrarchus labrax and Pagellus erythrinus. The discard rate of gillnets (50%) was found to be higher than that of longlines (12%). Average CPUE was calculated as 15.5 ± 19.8 kg/30 panels/day for gillnets and 1.7 ± 2.8 kg/100 needles/day for longlines; and the average daily catch (in kilograms) was found to be 10.8 ± 11.0 kg/boat/day for gill nets and 5.2 ± 4.3 kg/boat/day for longlines. In terms of average CPUE, there were statistically meaningful differences (t: -11.065; p: 0.000) between two gears and (gillnets, t: 4.382; p: 0.000; longlines, t: 3.973; p: 0.000) between cooperatives. In recent years, the number of species caught by gillnets in Gökova bay was observed to have decreased with increasing average CPUE value. In longline fisheries, on the other hand, both the number of species and the daily catch quantity per vessel have declined compared to former years. Measures such as increased conservation and control in the bay, a more efficient protection of no-take zones for all fishing activities (and expanding these zones if consensus established among stakeholders) and limitation of fishing capacity are believed to help increase the CPUE values.