A study on the morphometric characteristics of Astacus leptodactylus inhabiting the Thrace region of Turkey

This study was carried out to determine some morphological characteristics, and the length-length and length-weight relationships of freshwater crayfish (A. leptodactylus Eschscholtz 1823) in the area of Tekirdag, in the Thrace region of Turkey. The total length and wet weight for all individuals ranged from 33 to 156 mm and 0.64 to 96.42 g, respectively. Although the average length of both sexes was nearly the same, the average weight of male crayfish was higher than that of females. The total length-wet weight relationships for males, females and combined sexes of wet weight were found to be: WW = 7.10(6)TL(3.293), WW = 2.10(5)TL(3.022) and WW = 9.10(6)TL(3.224), respectively. Isometric growth for female crayfish and positive allometric growth for male crayfish were observed in all populations. The carapace length, carapace width, and chela length and width increased allometrically with total length (TL) in both sexes. In conclusion, the morphometric relations in A. leptodactylus observed in the present study could provide information for future studies and management plans

Age and growth of Atlantic bonito (Sarda sarda Bloch, 1793) in the Sea of Marmara and Black Sea, Turkey

Age and growth of Atlantic bonito (Sarda sarda Bloch, 1793) were determined in the Black Sea and Sea of Marmara from October 2003 to May 2005. A total of 694 samples ranging from 23.5 to 71 cm total length was collected; age estimates were carried out on otoliths of 248 fish. Male and female fish ages were estimated as up to 3(+). The length-weight relationship and the von Bertalanffy growth curve (TVBGF) were described for all individuals as: W = 0.0054L(3.215) and L-t = 68.01 [1 - e(-0.895 (t + 0.395))]. These data are discussed in relation to other growth studies of S. Sarda in the Mediterranean Sea

Distribution and composition of benthic marine litter on the shelf of Antalya in the eastern Mediterranean

In recent years, the pollution of the seas by the litter has identified as a serious environmental problem. Studies indicate that the majority of the marine litter consists of plastic, which is a result of human actions that also affected by river input, fishing activity and current systems. Thus, this study mainly focused on the distribution and composition of benthic marine litter. The sampling was carried out in Antalya Bay with a demersal trawl. A total of 68 hauls were performed and 370 pieces of 136.3 kg litter were collected. The density values vary between 13.3 and 651.1 n/km(-2) and weight values vary between 0.02 and 559 kg/km(-2) in overall litter. Distribution, density-weight indices by testing the differences with the depth, season and transect were analysed. Depth had a significant impact on both density and weight indices. Marine litter monitoring program is necessary for offering more solution proposals

Ecological distribution of demersal fish species in space and time on the shelf of Antalya Gulf, Turkey

This study provides baseline data on demersal fish assemblages in a heterogeneous but little-studied portion of the shelf of Antalya Gulf. The distribution of fish abundances along three transects subject to different fishing regulations, at depths of 10, 25, 75, 125 and 200m, was studied between May 2014 and February 2015 in the winter, spring, summer and autumn months. A total of 147 species belonging to 69 families were sampled. Lessepsian migrants from the Indo-Pacific region made up about a quarter of all species collected and some of them were found to greatly influence community structure. The spatial distribution of fish species was driven mainly by bathymetric gradient and two main assemblages were observed: shallow waters (10-25m) and deep waters (75-125m; 125-200m). Significant differences in community structure were found with regard to all the main variables: depth, transect, season and their interactions. Environmental variables measured concurrently with trawling were tested for correlation with fish abundances by canonical correspondence analysis (CCA). The results showed that the distribution of all species depends first on water depth and second on bottom type. The possible effects of fishing restrictions in the eastern part of the study area on assemblages are also discussed. In general, the spatial distribution and ecological processes of the fish community seem to depend on small variations in local environmental characteristics

Some marine leeches and first record of Branchellion torpedinis Savigny, 1822 (Annelida, Hirudinea, Piscicolidae) from elasmobranchs in Turkish waters, with new host records

Three species of marine leeches, Branchellion torpedinis Savigny, 1822, Pontobdella muricata (Linnaeus, 1758), and Stibarobdella moorei (Oka, 1910), were collected from Pteromylaeus bovinus (Geoffroy Saint-Hilaire, 1817), Dasyatis pastinaca (Linnaeus, 1758), and Raja miraletus Linnaeus, 1758, respectively, captured during a cruise aboard the R/V "Akdeniz SU" from depths of 10, 75 and 125 m in Antalya Bay, on the eastern Mediterranean coast of Turkey. Of these marine leeches, Branchellion torpedinis is recorded for the first time from Turkish waters on a new elasmobranch host, P. bovinus. In addition, R. miraletus is a new host record for Stibarobdella moorei, and Pontobdella muricata is recorded for the second time on its previously known host, D. pastinaca, from Antalya Bay