A REVIEW OF THE MARINE CRAB FISHERIES IN THE TURKISH SEAS

U radu je prikazana distribucija morskih kratkorepih rakova (Brachyura) uzduž turske obale ulovljenih između 1967. i 2016. te količina i vrijednost ekonomski značajnih vrsta rakova. Prethodni podaci ukazuju da je u Turskoj bilo prisutno 102 vrste kratkorepih rakova, od kojih je pet bilo ekonomski značajno, ali ovaj pregled identificira dodatne dvije vrste, Inachus phalangium i Ashtoret lunaris. U Egejskom moru ulovljeno je više vrsta rakova nego u Mediteranskom, Crnom i Mramornom moru. Najviše lovljene vrste su Callinectes sapidus, Maja squinado, Eriphia verrucosa, Carcinus aestuarii i Portunus segnis. Tijekom godina postojale su oscilacije u količini ulova kratkorepih rakova te je najniža s ulovom bila 2015.g. s 5 tona, a najviša 1984. g. s 2116 tona. Informacije navedene u radu pružaju temelj mogućem profitabilnom razvoju strategije očuvanja i upravljanja morskim rakovima u Turskoj.The paper presents a review of the distribution of marine crabs (Brachyura) along the Turkish coast and the amount of economically important marine crabs harvested between 1967 and 2016. Previous records reported that Turkey had 102 brachyuran crab species, only five of them being economically important, but this review identifies two more species, Inachus phalangium and Ashtoret lunaris. The Aegean Sea has more crab species than the Mediterranean, the Black Sea and the Sea of Marmara. The most harvested species are Callinectes sapidus, Maja squinado, Eriphia verrucosa, Carcinus aestuarii and Portunus segnis, respectively. This review shows that there have been fluctuations in the harvest of marine crabs between years, the lowest being 5 tonnes in 2015 and the highest, 2116 tonnes in 1984. The information provided in this review provides a basis for potential profitable development of conservation and management strategies of marine crabs in Turkey

The importance of sex, individual size and hide size in the hide use of freshwater crayfish (Astacus leptodactylus Eschscholtz, 1823)

A. leptodactylus’un barınak kullanımında eşeyin, birey büyüklüğünün ve barınak büyüklüğünün önemi araştırıldı. Aynı eşeydeki A. leptodactylus’ların barınak elde etmek için daha önceki barınak sahibiyle kavga etmediği, fakat eşeyler arasında kanibalizm derecesinde olmasa da barınak kullanımında bir rekabetin olduğu bulundu. Bu çalışmada ayrıca, A. leptodactylus’ların vücut büyüklükleriyle orantılı büyüklükteki barınakları daha yoğun kullandıkları gözlemlendi. Sonuç olarak, bu çalışma A. leptodactylus’ların barınak kullanımında, barınak sayısının ve büyüklüğünün oldukça büyük önem taşıdığını göstermektedir

The annual cycle of spermatozoa content in the vas deferens and some reproductive parameters in the narrow-clawed crayfish Pontastacus leptodactylus (Eschscholtz, 1823)

Understanding the annual dynamic of gametes in crayfish is useful for successful management of crayfish population. The annual variations in spermatozoa content of vas deferens, gonado-somatic index (GSI), hepatosomatic index (HSI), vas deferens index (VDI), and testicular index (TI) were investigated in male Pontastacus leptodactylus. The spermatozoa content, GSI, HSI, VDI, and TI of P. leptodactylus significantly (P < 0.05) changed during different seasons of the year. For example, significantly higher spermatozoa number, GSI, VDI, and TI were recorded in January (P < 0.05). On the other hand, the HSI reached the peak in August (P < 0.05). The spermatophore degeneration started in April. Although the vas deferens lacks spermatophore structure during the summer, the presence of spermatozoa was observed throughout the year. This study represents a step forward in understanding the seasonal spermatozoa content and the reproductive status of male P. leptodactylus. Keywords: Decapoda, Gonado-somatic index, Hepatosomatic index, Spermatophore, Vitellogeni

An investigation on the sperm number and reproductive parameters of males in wild caught freshwater crayfish Astacus leptodactylus

In the present study, the sperm number of wild caught Astacus leptodactylus was counted in the beginning of reproduction season. In addition, the reproductive system, testes, and vasa deferentia were weighed, and gonado-somatic index and testicular index were calculated. Twenty-five adult males of A. leptodactylus were used for the study. Significant linear regressions were found between body length (and weight) and sperm count, reproductive system weight, testes weight and vasa deferentia weight (P < 0.05). The mean sperm number of vas deferens for the size range of 41-56 mm carapace length crayfish was 5.72 +/- 4.54 x 10(9) sperm/distal vas deferens (DVD) section. Sperm number ranged from 4 x 10(8) to 8.5 x 10(9) sperm/DVD section. The results revealed that an increase in body weight causes an increase in sperm number. For example, mean sperm number was 3.87 +/- 2.87 x 10(9) for the weight range of 15-24 g crayfish, 5.01 +/- 2.62 x 10(9) for the weight range of 25-35 g crayfish and 7.37 +/- 2.87 x 10(9) for the weight range of 36-42 g crayfish. In conclusion, this study provides some data on the male reproduction characters and needs to be improved with details about the reproductive performance of males (i.e., sperm number and quality) in order to reach a maximum reproductive efficiency in captivity

A Review of the Marine Crab Fisheries in the Turkish Seas

The paper presents a review of the distribution of marine crabs (Brachyura) along the Turkish coast and the amount of economically important marine crabs harvested between 1967 and 2016. Previous records reported that Turkey had 102 brachyuran crab species, only five of them being economically important, but this review identifies two more species, Inachus phalangium and Ashtoret lunaris. The Aegean Sea has more crab species than the Mediterranean, the Black Sea and the Sea of Marmara. The most harvested species are Callinectes sapidus, Maja squinado, Eriphia verrucosa, Carcinus aestuarii and Portunus segnis, respectively. This review shows that there have been fluctuations in the harvest of marine crabs between years, the lowest being 5 tonnes in 2015 and the highest, 2116 tonnes in 1984. The information provided in this review provides a basis for potential profitable development of conservation and management strategies of marine crabs in Turkey

Effect of dietary n 3 series fatty acids on sperm production in the freshwater crayfish Astacus leptodactylus Eschscholtz Astacidae

The objective of the present work was to evaluate the effects of three different rates of long chain n-3 polyunsaturated fatty acid (LC n-3 PUFA) on the sperm number of Astacus leptodactylus. The experiment was carried out with the four following treatments: control group (not supplemented LC n-3 PUFA), D1 (1 %), D2 (2 %) and D3 (3 %). The sperm number of A. leptodactylus was counted; the reproductive system was weighted; and the macroscopical analysis of the testes and vasa deferentia (DVD) were conducted. In addition, gonado-somatic index (GI) and testes index (TI) were also calculated. The results showed that there was a significant difference between the crayfish fed LC n-3 PUFA supplemented diets (D1, D2, D3) and control in mean sperm number (P 0.05), but there was not a significant difference in the TI of the crayfish fed control, D1, D2 and D3 (P > 0.05). In conclusion, diets containing different levels of LC n-3 PUFA significantly increase the sperm number of A. leptodactylus, and they are crucial for the production of higher number of sperm in this species