Temporal changes in some Rajiformes species of cartilaginous fish (Chondrichthyes) from the west coast of İskenderun Bay (northeastern Mediterranean)

Authors : Hacer YELDAN, Dursun AVŞAR, Sinan MAVRUK, Meltem MANAŞIRLI

Pages : 693-698

Doi:10.3906/yer-1201-6

View : 24 | Download : 8

Publication Date : 0000-00-00

Article Type : Research Paper

Abstract :Some Rajiformes species among the cartilaginous fish insert ignore into journalissuearticles values(Chondrichthyes); that are distributed on the west coast of the Gulf of İskenderun were seasonally obtained by bottom trawling from 2 different depth layers between the years 2004 and 2011. The spatiotemporal changes in catch per unit effort insert ignore into journalissuearticles values(CPUE); values were investigated by considering 2 depth contours insert ignore into journalissuearticles values(10 and 20 m);. Six species belonging to 6 different Rajiformes families were identified during the sampling period, including Dasyatis pastinaca insert ignore into journalissuearticles values(common stingray);, Gymnura altavela insert ignore into journalissuearticles values(spiny butterfly ray);, Rhinobatos rhinobatos insert ignore into journalissuearticles values(common guitarfish);, Raja radula insert ignore into journalissuearticles values(rough ray);, Myliobatis aquila insert ignore into journalissuearticles values(common eagle ray);, and Torpedo marmorata insert ignore into journalissuearticles values(marbled electric ray);. A general linear model was used to analyze the changes in the total and separate weights of cartilaginous fish. For this purpose, the logarithms of CPUE values in weight were classed according to the depth, season, and years. Seasonal variations and year–season 2-way interactions were found to be highly significant for total cartilaginous CPUE values insert ignore into journalissuearticles values(P < 0.01);. The annual changes in R. rhinobatos were the only significant annual difference insert ignore into journalissuearticles values(P < 0.05);, while the year–season interactions of D. pastinaca were found to be significant insert ignore into journalissuearticles values(P < 0.01);. The seasonal variations of D. pastinaca and G. altavela were also highly significant insert ignore into journalissuearticles values(P < 0.01);.
Keywords : Key words Cartilaginous fishes Chondrichthyes, İskenderun Bay, biomass