The present study describes the abundance and biomass distribution of gelatinous macrozooplankton in relation to physical parameters in Hamsilos Bay. Gelatinous macrozooplankton samples were collected monthly from four stations between July 2015 and June 2016 using a plankton net with a 112 μm mesh size and a 50 cm diameter mouth opening by vertical hauls. Four gelatinous macrozooplankton species were identified: Aurelia aurita (Linnaeus, 1758); Mnemiopsis leidyi A. Agassiz, 1865; Beroe ovata Bruguière, 1789; and, Pleurobrachia pileus (O.F. Müller, 1776). The maximum mean abundance of gelatinous macrozooplankton was recorded in August 2015 (24.58 ind. m-2), whereas the maximum mean biomass was recorded in April 2016 (147.79 g m-2) from four sampling stations. The abundance and biomass of gelatinous macrozooplankton increased in the summer and spring. M. leidyi and P. pileus were primarily responsible for the increase in total gelatinous macrozooplankton abundance in the summer, whereas A. aurita and B. ovata were primarily responsible for the increase in total abundance in the spring and autumn. The abundance and biomass of M. leidyi were positively correlated with temperature and negatively correlated with dissolved oxygen.

Türkiye denizlerinde yaşayan üç barbunya (Mullus barbatus ponticus, Mullus surmuletus, Upeneus moluccensis) türünün büyüme ve populasyon parametrelerinin tahmin edilen araştırma 1-Eylül 2014-15 Nisan 2015 tarihleri arasında yürütülmüştür. Araştırma verileri Karadeniz (Samsun) ve Akdeniz (Mersin) kıyılarında demersal trol avcılığı yapan ticari balıkçı gemilerinden temin edilmiştir. Türlerin ortalama boyları sırasıyla12.67±0.09 cm, 11.55±0.11 cm ve 13.48 ±0.08 cm şeklinde belirlenmiştir. Boy ağırlık ilişkisi denklemleri ise Mullus barabatus ponticus için W=0.0132L2.9066, Mullus surmuletus için W=0.0088L3.101 ve Upeneus moluccensis için W=0.0079L3.002 şeklinde hesaplanmıştır. Büyüme parametreleri sırasıyla asimptotik boyları (L∞) 25.08 cm, 27.3 cm ve 23.5 cm, brody büyüme katsayısı (K) 0.24, 0.52 ve 0.61 şeklinde ve balığın doğmadan önceki yaşı (t0) -1.82, -3.65 ve -1.05 olarak tahmin edilmiştir. Türlerin anlık ölüm oranları (Z), doğal ölüm oranları (M) ve balıkçılık ölüm oranları (F) sırasıyla 2,96; 4.57; 2.17, 0.48;0.80;0.85, 2.48; 3.52; 1.32 olarak saptanmıştır. İşletme oranı (E) ise Mullus barabatus ponticus için 0.83, Mullus surmuletus için 0.82 ve Upeneus moluccensis için 0.60 şeklinde bulunmuştur. Araştırmada türler için tahmin edilen tüm parametreler daha önceki yapılan çalışmalar ile karşılaştırılmıştır.

This study aims to provide a comprehensive summary of the fundamental biological and certain population characteristics of Ciona intestinalis found along the Black Sea coasts of Turkey. The research was conducted between September 2022 and April 15, 2023, off the Sinop coast of the Black Sea, utilizing samples collected by commercial fishing vessels in the region. A total of 103 specimens of Ciona intestinalis were examined during the study. The average total length, width, and weight of Ciona intestinalis were determined to be 3.614 ± 0.089 cm, 1.967 ± 0.054 cm, and 2.004 ± 0.067 g, respectively. The length-weight relationship (LWR) and length-width relationship (LWdR) of Ciona intestinalis were established as W = 0.3996L1.2424 (R = 0.9389), Wd = 0.5362L + 0.0237 (R = 0.8897) and W = 0.9443Wd1.0889 (R = 0.8786) respectively. This study presents, for the first time, the LWR LWdR and WdWR for Ciona intestinalis, a species of significant importance in the benthic ecosystem of the Black Sea. It is anticipated that this research will lay the groundwork for future investigations into population dynamics and biological aspects of this species.

This study was conducted out in the southern Black Sea coastal zone, in 2011-2016 fishing seasons. In the study, bycatch of sturgeons and cetaceans were examined both in small scale (turbot gillnets) and large scale (trawlers) fisheries. During the fishing operations within the study, 66 sturgeons (41 Danube sturgeon - Acipenser gueldenstaedtii and 25 starry sturgeon - Acipenser stellatus) and 49 cetaceans (40 harbor porpoises - Phocoena phocoena relicta and 9 short beaked dolphin - Delphinus delphis ponticus) were captured. Length-weight relationships of Danube sturgeon and starry sturgeon were determined as W=0.0123L2.8808 (R=0.9964, negative allometric growth) and W=0.0345L2.5351 (R=0.9961, negative allometric growth), respectively. Mean total length were calculated as 60.02±1.04 cm for Danube sturgeons, 46.42±1.17 cm for starry sturgeon and mean fork length were established as 126.75±3.36 cm for harbor porpoises, 163.74±1.42 cm for short beaked dolphins in the study.

Environmental pollution resulting from the rapid increase in human population, urbanization, intensive use of chemicals in agriculture, and industrial development has reached a level that threatens natural life today. Trace elements are one of the most important factors causing significant levels of pollution in the environment and are added to marine ecosystems in high concentrations because of both natural cycles and non‐cycle factors. While essential metals show functional properties by entering the structural composition of living organisms at low concentrations, it is known that non‐essential metals do not have any biological function. Deficiency or high concentrations of metals, which are required in trace amounts by living organisms for vital events, and the effect of toxic metals at low concentrations cause disturbances in metabolic and physiological events, accumulation in tissues and organs, and are transported to higher trophic levels at increasing values through the food chain, ultimately causing significant environmental and health problems. The aim of this study was to determine the concentrations of Al, Cr, Mn, Fe Co, Ni, Cu, Zn, As, Cd, Hg, and Pb in the muscle tissues of Squalus acanthias , Raja clavata , and Dasyatis pastinaca from the southern Black Sea. By focusing on these non‐commercial but ecologically important top predators, the study contributes to the assessment of ecological risks and management strategies for the region.