Kadir Seyhan

Feeding behaviour of whiting, Merlangius merlangus, L. in captivity

Abstract The feeding behaviour of medium sized (155.25±27.98 cm, n =8) whiting, Merlangius merlangus , under laboratory conditions was investigated with continuous food availability. This investigation was made using both natural, Sprattus sprattus , and artificial diet which was monitored with a periodogram analysis obtained by a newly developed demand feeding unit. The return of appetite of large whiting (305.85±056.90 cm) was also studied. Medium size whiting consumed 5.29 g (wet weight)/day corresponding to 3.41% body weight, approximately three sprats of 1.88 g each. The return of appetite after a single meal was found to follow the gastric emptying curve closely. If food is not offered directly but made available through demand feeding, the whiting feed rhythmically (every 21 h); under these conditions, it was estimated that feeding activity returns when the stomach is 40% full.

Seasonal and spatial variations of marine litter on the south-eastern Black Sea coast

The south-eastern Black Sea coast in Turkey was evaluated for marine litter composition and density covering nine beaches during four seasons. The marine litter (>2cm in size), was collected from the coast and categorized into material and usage categories. The data analysis showed that plastic was the most abundant litter (≥61.65%) by count and weight followed by styrofoam and fabric. The marine litter density ranged from 0.03 to 0.58 with a mean (±SD) of 0.16±0.02 items/m2 by count. Based on weight, it varied between 0.44 and 14.74g/m2 with 3.35±1.63. The east side had a higher marine litter density than the west side with significant differences between beaches. The variations due to different seasons were not significant for any beach. The results of this study should provide baseline information about the coastal marine pollution and will assist the mitigation strategies.

Age, growth, reproduction and diet of the Flatsnout Goby, Neogobius platyrostris (Pallas, 1814), on the south-eastern Black Sea Coast of Turkey

Abstract Information is given on the age structure and growth, length at first maturity, annual cycle of gonad development and diet of the Flatsnout Goby, Neogobius platyrostris (Pallas, 1814), in the Black Sea of Turkey. The maximum age was found to be 5 and 6 years for males and females, respectively. The von Bertalanffy growth parameters were estimated from the mean age-length data for males and females (males: L ∞=21.7 cm; females: L ∞=16.3 cm) and the growth performance indices were calculated for males φ’=4.21 and for females φ’=4.03. The estimated length at first maturity was 9.29 and 7.50 cm for males and females, respectively. The spawning season was between March and June. Total fecundity ranged from 103 to 990, with an average of 553±82 ripe eggs/fish. The Flatsnout Goby feeds on a wide variety of prey items, particularly on Gammaridae, Brachyura, Pisces and Isopoda.