This study was conducted using monthly data collected between July 2015 and June 2016 in the marine area of Hamsilos Nature Park, located in Sinop, Southern Black Sea. The primary objectives were to determine the diversity of ichthyoplankton assemblages, examine seasonal variations, assess spatial differences between the inner and outer parts of Hamsilos Bay, and highlight the ecological relationships of the predominant species with environmental factors. The comprehensive collection during the study resulted in a mean abundance of 2217 eggs.10 m² and 2743 larvae.10 m², with 28 species belonging to 21 families identified. Specifically, Engraulis encrasicolus is the most abundant in spring and summer, Gaidropsarus mediterraneus is the most abundant in autumn, and Sprattus sprattus is the most abundant in winter. A temporal analysis revealed the highest abundances in August, September, and July, with the lowest in April, May, and February. Significant seasonal differences in abundance and diversity were detected. No spatial differences were found between the inner and outer areas of Hamsilos Bay. Small pelagic species dominated the ichthyoplankton community, while demersal species, though diverse, were less abundant. According to the results of the DistLM analysis, the structure of the ichthyoplankton community is influenced by temperature and salinity. During the study, the water temperature ranged from 8.35 °C in February to 25.50 °C in August, and the salinity varied from 17.67 psu in September to 19.04 psu in May.

This study investigated the taxonomic composition, abundance, and biomass values of mesozooplankton in the marine area in front of two important rivers (Sakarya River and Yeşilırmak River) and the largest port located on the Black Sea coast in Türkiye (Samsun Port) in July 2019 and January 2020. The average mesozooplankton abundance and biomass were 4187.3 ind. m-3 and 89.7 mg m-3 in Sakarya River, 3638.5 ind. m-3 and 78.2 mg m-3 in Samsun Port, and 3327.6 ind.m-3 and 77.6 mg m-3 in Yeşilırmak River, respectively. In July 2019, the highest abundance value of mesozooplankton (8581 ind. m-3) was recorded at SAK08 station off Sakarya River due to the copepod $Acartia$ $clausi$ (3279 ind. m-3). In July 2019, the highest biomass value of mesozooplankton (209.34 mg m-3) was found at YSL07 station off Yeşilırmak River with the contribution of the copepod $Centropages$ $ponticus$ (77.90 mg m-3). In January 2020, the highest abundance and biomass values of mesozooplankton (4035 ind. m-3 and 66.45 mg m-3) were detected at SLI05 station off Samsun Port due to copepod $Acartia$ $clausi$. A difference in mesozooplankton species composition between the two sampling periods was identified. While Cladocera species and copepod $Acartia$ $tonsa$ were exclusive at the sampling stations in July 2019, copepod $Calanus$ $euxinus$, $Pseudocalanus$ $elongatus$ and $Oithona$ $similis$ were observed at the sampling stations in January 2020. Also, in January 2020, the presence of freshwater Cladocera species was detected off Sakarya River. The changes in biodiversity were determined to depend on temperature changes and riverine input.

This study examined preserved marine fish specimens collected from numerous field surveys conducted along Türkiye’s Black Sea, Marmara, Aegean, and Mediterranean coasts since 1965. Our review and categorization of these materials revealed that the specimens belong to 360 species from 131 families. Current data shows that the museum collection includes 20 species of cartilaginous fish and 8 species of bony fish listed as endangered on the IUCN Red List, alongside 54 non-native fish species. Prepared according to museum standards by Ege University Fisheries Faculty’s Scientific Material (ESFM), this collection of Turkish marine fish constitutes 66% of all Turkish marine fish fauna. This makes it the largest and oldest marine fish collection in Türkiye. Considering Türkiye’s maritime borders with neighboring countries, this collection is significant nationally and globally. Given the diverse marine fish species in Turkish seas over the past half-century, this preserved material is a vital reference for local and foreign ichthyologists. If organized and transformed into a visitable museum, this extensive collection could raise awareness about the diversity of marine fish species in our seas. As a result, we have established the ” biological repository of Turkish Marine Fish Department” in the Faculty Museum, now known as the Fisheries Faculty’s Scientific Material (ESFM) at Ege University. We present the fish in the collection as a species list.