In this study, the selectivity of commercial and alternative (experimental) codends for the deep-water rose shrimp, Parapenaeus longirostris, in the Aegean Sea demersal trawl fishery was investigated. Tested were the 44-mm diamond mesh codend as used in commercial fisheries (D44), in addition to a 50 mm diamond (D50), a 40 mm square (S40), and a 40 mm 90° turned mesh (T40), respectively. Sea trials were carried out in the eastern Aegean Sea, with a local commercial trawler using a modified trawl net with 620 meshes circular mouth opening. A total of 35 valid daytime hauls (8 with D44, 9 with D50, 8 with S40 and 10 with T40) were carried out. Selectivity data were collected using the covered codend method and analysed by means of a logistic equation with the maximum-likelihood method. Mean selection curves were estimated and compared using the between-haul variations model. The mean 50% retention carapace length values (LC50) were estimated as 21.2 ± 0.1, 23.2 ± 0.3, 20.8 ± 0.2 and 20.5 ± 0.4 mm CL for D44, D50, S40, and T40, respectively. Selection range (SR) values were determined as 4.9 ± 0.1 mm in D44, 8.7 ± 0.3 mm in D50, 4.0 ± 0.3 mm in S40, and 10.1 ± 0.3 mm in T40. While haul duration and total catch among the parameters did not affect the LC50 values for the investigated codends, the value of the parameter describing the weight of P. longirostris caught in that codend showed an effect for the D50 and T40 codends. Consequently, all investigated codends yielded sufficient LC50 results when considering the minimum landing size (MLS) value imposed by the EU (20 mm CL). In conclusion, the legally allowed S40, which gave an LC50 value close to that of D44, and which would be the preferable codend in terms of its releasing characteristics for individuals under the MLS value (89%), can be used as a good alternative for the D44 (preferred by the fishermen) in the deep-water rose shrimp fishery.

Abstract:Realizing the developments in fishing fleet in time is of great importance for the determination of the future strategies in fisheries management. In this study, changes occuring in the last 29 years in the fishing fleet of Muğla Province having the longest coastline in Turkey and composing 10 % of Turkey's fishing fleet, reasons of increase and decrease in fleet, vessel features and fishing types in the current situation were determined by analysing the records of Muğla Food, Agriculture and Livestock Province Directory. The reduction ratio of fleet recorded by identifying the features, numbers and types of the fishing vessels which were removed from the fleet within the scope of "The Notification to Support the Removal of Fishing Vessels from the Fleet (2012/51)" has been determined. The number of fishing vessel in Muğla increased between 1985 and 2005, but has shown decrease between the years 2005 and 2013. In this 29-year period, the total number of the fishing vessels transferred from the fishing fleet is 359. Their reasons of these transfers have been determined as not renovating the licence for 233 fishing vessels, fishing in a forbidden area for 1 boat, licence integration for 1 boat, transformation to a cruise ship for 1 boat, selling 108 boats to other cities and utilisation of donation support for 15 boats. Instead, the number of boats that were transferred from other cities was 234. According to 2013 data, the fishing fleet of Muğla has 1.428 fishing vessels 97,1% of which are longline fishing, 1,7 % are seine fishing, 0,9 % are trawl and 0,3 % are auxillary service boats. The percentages of the fishing vessels transferred from the fishing fleet within the notification numbered 2012/15 are as follows; 40 % of them are longline fishing, 40 % are seine fishing, 20 % are trawl fishing vessels. Although the fishing vessels transferred from the fleet thanks to the grant support have provided decrease by 1% in number and 2% in length, they have enabled a decrease in engine power by 7% and in gross ton by 23%. Despite the fact that the grant support program wasn't able to be implemented in Muğla in terms of number and length, it was considered as effective in engine power and gross ton. The changes in the fishing fleet after 2005 have shown that there is a fishing pressure on fish stocks and fishing is not economic any more. Keywords: Muğla, fishing fleet, fishingÖzet Balıkçılık filosunda zaman içerisinde kaydedilen gelişmelerin tespit edilmesi balıkçılık yönetiminde gelecek stratejilerinin belirlenmesi için önem arz etmektedir. Bu çalışmada; Türkiye'nin en uzun kıyı şeridine sahip ve Türkiye filosunun % 10'unu oluşturan Muğla ili balıkçılık filosunun son 29 yıllık değişimi , filodaki artış ve azalışların sebepleri, mevcut durumda balıkçı gemisi özellikleri ve balıkçılık türleri Muğla İl Gıda, Tarım ve Hayvancılık Müdürlüğü kayıtları incelenerek tespit edilmiştir. "Balıkçı Gemisini Avcılıktan Çıkaranlara Yapılacak Destekleme Tebliği (2012/51)" kapsamında 2012 yılında Muğla ili balıkçılık filosunda...