The food composition of whiting, Merlangius merlangus, caught around the sea-cage fish farms off the coast of Perşembe, was analysed and compared with the diet of whiting from a control site off the coast of Fatsa (Ordu Province, south-eastern Black Sea). A total of 815 stomach samples were collected during the study, and of these, 195 (23.9%) were empty. According to the percentage of relative importance index (IRI%), pellet food (47.8%) and Annelida (25%) were the main prey groups of whiting in the sea-cage fish farms area, while unidentified teleost (85.3%) and Engraulis encrasicolus (8.2%) were dominant in the control site. The other prey groups in both areas were Crustaceans (Mysidae, Amphipoda, Upogebia sp.), Sprattus sprattus and Gobius spp. Seasonally, pellet food was the most consumed food in all seasons, but Mysidae was the first preference of whiting around the sea-cage fish farms in spring. In the control site, unidentified teleost was the first preference in all seasons, except winter, where E. encrasicolus was the first choice, followed by crustaceans and S. sprattus in winter. Bray–Curtis analysis shows that seasonally, there is no significant difference in the sea-cage fish farms, while there is significant difference in the control site, and two-dimensional nMDS of IRI% revealed a clear separation between both sites. SIMPER analysis revealed that the most contributing factors to the differences between seasons were pellet food in the sea-cage fish farms, and E. encrasicolus in the control site.
Pterois miles (Bennett, 1828) is an aquatic invader and disruptive predator for marine ecosystems. A single lionfish was photographed and sampled in March 2021 during a scientific survey at 36 m depth in Karaburun/İzmir Bay. In this study presents an update on the lionfish's northward progression in the Aegean Sea.
More than fifty published on demersal trawl codend selectivity studies have been carried out in the Mediterranean waters of Turkey since the mid-1980s. In this study, in an attempt to enhance the size selectivity of three species in the Aegean Sea trawl fisheries, three 90 o turned meshes codens were investigated. Experiments were carried out in the Kuşadası Bay of the Eastern Mediterranean, between 19 January and 29 March 2015 with commercial stern trawler. The meshes of tested codends were turned 90 o , two of them have 44 mm mesh size with 300 and 150 meshes around codend circumferences (44T300 and 44T150). The other has 40 mm mesh size with 165 meshes around codend circumferences (40T165). Individual hauls and mean selectivity parameters were estimated by using the CC2000 and EC-Modeller softwares, respectively. The mean L50 values of 44T300, 44T150 and 40T165 were 17.5 ± 0.2 mm, 18.6 ± 0.1 mm and 17.1 ± 0.2 mm carapace length for shrimp, 16.4 ± 0.4 cm, 17.1 ± 0.4 cm and 14.8 ± 0.2 cm total length for horse mackerel, respectively. The pooled L50 values of, 12.8 ± 0.5 cm, 13.2 ± 0.6 cm and 12.1 ± 0.1 cm total length for hake. While there are no differences between L50 values of 40T165 and 44T300 for deepwater rose shrimp (p>0.05), there are significant differences for horse mackerel (p<0.05). The likelihood ratio test results showed that there were no significant differences among all codends for European hake. In conclusion, any effort such as using square mesh, turned mesh codends or halved the number of meshes in the codend to release immatures of some species, is probably to cause the loss of marketable sizes of other species in the Mediterranean. This economical loss of revenues is the essential concern of fishermen that prevents them using alternative codend designs, though such designs are technically applicable. Consequently, the losses of income caused by using T90 mesh codend and halving the number of meshes around codend circumference should also be investigated in future studies.
Deployment of artificial wreck reefs (AWRs) near natural reefs can influence fish assemblages on both reefs. Here, we assessed fish attitudes (abundances, biomass and species richness) according to different level complexity areas of wrecks, feeding guilds of fish and body size of fish of two identical AWRs deployed at the same depth (36.6 m) and different distances from natural reefs. Scuba divers used visual census method to sample fish communities at wrecks for two years. An average of 2346 individuals per dive belonging to 52 species were observed on wrecks combined. Both mean fish abundance and mean biomass did not differ significantly between wrecks. Mean species richness was significantly greater at 9 Eylül than Alaybey. Planktivore was the most abundant feeding guild on wrecks, and its abundance statistically differed between AWRs. The comparisons of fish assemblages at the different level complexity areas of the wrecks show differences, the highest mean abundances were recorded at the areas of low complexity of the wrecks. The results of this study show that although deploying artificial wreck reefs near to natural rocky reefs catalyses fish colonization, it does not present an exact influence on the fish communities of AWRs. We have not known yet how creating an artificial wreck reef affects fish community of natural reefs. With giving extra importance to the choice of deployment area, AWR applications may transform to win-win projects for both the marine environment and recreational users, such as divers and anglers.
Ekonomik, teknolojik, askeri ve bilimsel gelişmeler, insanoğlunun bilinmeyene ulaşmasına ön ayak olmuştur. Zaman içerisinde yaşanan teknolojik imkânlardaki artış insanoğlunu su altına yöneltmiş ve su altında gerçekleştirilen keşifler bilimsel temelde meydana gelmeye başlamıştır. Bu çalışmada Türk üniversitelerinde dalışı bir araç veya amaç olarak kullanan başlıca disiplinlerden su ürünleri ve deniz bilimlerinde gerçekleştirilen çalışmaların nicel olarak incelenmesi hedeflenmiştir. Çalışma Mayıs 2018 -Ağustos 2019 tarihleri arasında ülkemiz üniversitelerinin su ürünleri ve deniz bilimleri alanlarında görev yapmakta olan akademisyenler ve lisansüstü öğrencilerle yüz yüze ve çevrimiçi anketler vasıtasıyla yürütülmüştür. Aktif olarak bilimsel dalış yaptığını ifade eden 65 araştırmacı ankete katılım sağlamıştır. Katılımcıların yalnızca 3'ü bilimsel dalıcı brövesine sahiptir. Türkiye'de bilimsel dalış yapabilmek için bilimsel dalıcı sertifikasına sahip olma zorunluluğu yoktur. Katılımcıların %62'sinin görüşü bu durumun devam etmesi yönündedir. Ancak katılımcıların %55'i Türkiye'de ulusal bir bilimsel dalış komitesinin oluşturulması gerektiği kanaatindedir. Böyle bir bilimsel komite, bilim insanlarının denizel yaşamı ve sahip olduğu değerleri anlatmak için gösterdiği çabayı daha görünür hale getirme potansiyeline sahiptir.
Şensurat-Genç T., Seyhan-Öztürk D., Iwatsuki Y. 2020. First record of the doublebar seabream, Acanthopagrus bifasciatus (Actinopterygii: Perciformes: Sparidae), in the Aegean Sea. Acta Ichthyol.Piscat. 50 (1): 97-101.Abstract. The present paper reports the second record of a Lessepsian migrant, Acanthopagrus bifasciatus (Forsskål, 1775), in the Mediterranean Sea and first record from the Aegean Sea. The species is distinguished by the counts of 5½ scale rows between the fifth dorsal-fin spine and lateral line, dorsal and caudal fins yellow, without a dense black margin of dorsal-fin or narrow black edge along rear margin of caudal fin which is being diagnostic characters of this species.
This study presents the catch records of a coastal fisherman during daily fishing trip between 2017 and 2018 in Yenişakran, Çandarlı Bay (Aegean Sea). The trammel net and longline were used at depths of 5-25 m on a sandy bottom and the sea meadows during the year. A total of 39 species were identified from the both trammel netting and the longlining. Mean catch per unit effort (CPUE) values (8.7±0.1 kg/1000 m net and 12.9±0.8 kg/1000 hooks) shown that longlining was more efficient fishing gear than the trammel netting. In terms of mean CPUE values, there is significantly difference between trammel netting and longlining (p<0.05).
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