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Stomach content analysis of fish not only helps document their food spectrum but also provides an overview of the food network they are involved in. In this study, we aimed to investigate the food composition of L. guentheri from the Iskenderun Bay, northeastern Mediterranean Sea. Specimens were collected between January 2022 and August 2022. A total of 215 L. guentheri specimens stomachs were examined during the study for stomach content analysis. All stomachs were analyzed, 60 (27.9%) were empty and 155 (72.1%) contained food items. Analysis of diet composition showed that the species is carnivorous and prey on teleosts, crustaceans, bivalves and cephalopods. When the food composition of the samples is analyzed numerically, teleost was the most important prey (68%), followed by crustaceans (14%), bivalves (5%), cephalopods (0.5%) and unidentifiable materials (12.5%). Bony fish species such as Plotosus lineatus, Parupeneus forsskali, Saurida lessepsianus, Scorpaena sp. and Siganus sp. were identified in the food composition. Therefore, it is thought that this species has a high feeding tendency towards bony fish species. This study increases the knowledge about the food composition of L. guentheri on the Mediterranean coast of Türkiye. [ABSTRACT FROM AUTHOR]

One specimen of Korean rockfish Sebastes schlegelii Hilgendorf, 1880 was caught by using a fish net at a depth of 7 m on 14 May 2022 from Akçakoca, Düzce in the Black Sea. In this study, the Korean rockfish Sebastes schlegelii from the Black Sea coast of Türkiye is reported for the first time with both morphologic and genetic evidence. S. schlegelii is characterised by 5 spines on the preoperculum and 2 spines on the operculum. Genetic analyses using mtDNA COI gene region also confirmed the species as Sebastes schlegelii. This species is thought to have been transported to the Black Sea from other seas of the world, probably via ballast waters or aquarium escape. The most important reason for this is that the species has not been detected in the Mediterranean. [ABSTRACT FROM AUTHOR]

Objective: In fisheries biology, length-weight relationship data are commonly used and helpful for determining the weight of an individual fish of known total length or total weight from length-frequency distribution. The present investigation aims to estimate the length-weight relationships and Fulton's condition factors from the southeastern Mediterranean coast of Türkiye. Materials and Methods: A total of 368 red cornetfish, Fistularia petimba Lacepède, 1803 (203 females and 165 males) specimens were collected from the İskenderun Bay (southeastern Mediterranean, Türkiye) within the fishing periods of April 2019 and March 2020, caught by commercial bottom trawler at 28-42 m depths. Fish samples were measured in total length (TL) to the nearest 0.1 cm, and the total weight was scaled to the nearest 0.01 g. Results: The total length ranged from 21.50-56.60 cm, and the weight ranged from 8.10-94.04 g for Fistularia petimba. The length-weight relationship was found as the W = 0.00033 × L3.126 (r² = 0.963) for both sexes. The value of b is slightly different than 3 and showed positive allometric growth. The condition factor was found to be 0.539 for females, 0.526 for males, and 0.520 for both sexes. Conclusion: This study is the first investigation of the length-weight relationship and condition factor for Fistularia petimba from İskenderun Bay. The present study provides the basic fisheries parameters for this species in the Mediterranean Sea, which will be useful for fisheries management and fish population dynamics. [ABSTRACT FROM AUTHOR]

Underwater visual census (UVC) is a commonly used approach for assessing fish density and biomass. Iskenderun Bay, comprising the Samandag coast in Turkey, is the most important introduction pathway of alien species in the northeastern Mediterranean. In this study, the density, abundance, distribution and interaction of invasive lionfish or devil firefish Pterois miles were assessed using the UVC method on the Samandağ coast. The total transect area monitored on the Samandağ coast was 4.500 m². Species richness, Shannon's diversity index and rate of biomass were 25, 1.81 and 73.5 m², respectively. Reduced diversity was observed with increasing depths. The sandy seafloor was a limiting factor for lionfish distribution. There was a significant positive correlation between lionfish total density and both the Shannon diversity index (r = 0.99, P<0.001) and Shannon evenness index (r = 0.99, P<0.05). A high number of significant positive correlations (P<0.05) were detected between the occurrence of lionfish and the occurrence of both the native species and other alien species. The first stock assessment study of lionfish by the UVC method in Turkish marine waters revealed that native species are under very high pressure from lionfish species, especially Chromis, Sparids and Wrasses, indicating negative effects of lionfish on regional native biodiversity. [ABSTRACT FROM AUTHOR]

parus aurata is a very important fish, in fisheries and aquaculture. In this study, the genetic impact of cultured gilthead sea bream S. aurata was examined on wild stocks in the Iskenderun Bay (Northeastern Mediterranean) by genetic and morphological analyzes. Morphometric traits of gilthead sea bream were investigated using a traditional set of measurements and network system. In total, 91 morphometric characters were measured for the Biomorph v3 of measurements and 14 for the truss network system. Results of discriminant function analysis (DF), three functions were produced, and the first two discriminant functions (DFs) explained 90.1% of between-group variability and plotting DF1 (55.2%) and DF2 (34.8%). Mitochondrial DNA sequencing of 16S rRNA region was found to be 830 base pair and 21 bp variable and 3 bp parsimony informative sites between populations. The nucleotide composition was found to be 21.1%, 24.1%, 32.9% and 21.1% for T, C, A and G, respectively. The average value of genetic diversity and genetic distance within populations was found to be 0.00316 and -0.00088, respectively. Haplotype diversity of the cultured population was found to be 0.6710 while the wild population was found to be 0.8333. In the present study, the morphological and molecular analysis identified cultured fish escapees in the wild data set sampled in the aquaculture sites. Despite a mixed gene pool in the wild population, as a result of a long-term culture period of fish originating from Mediterranean broodstocks, the molecular genetics tools identified potential cultured escapees. [ABSTRACT FROM AUTHOR]

Chitosan is a biocompatible, biodegradable, non-toxic, antibacterial, antioxidant, and antifungal natural polymer. In this study, chitin and chitosan were chemically isolated from the exoskeleton of invasive swimming crab Charybdis longicollis. In order to obtain the chitin, demineralization, deproteinization, and decolourization steps were applied to the samples. Chitosan was prepared from the isolated chitin by deacetylation at high temperatures. The chemical composition of chitin from C. longicollis was characterized by XRD and FTIR analysis. The yield of chitin extraction from dry crab shells was 25.78 %. The yield of chitosan produced from extracted chitin was 80.23 %. The experimental analyses revealed that the obtained chitin and chitosan could be used as biomaterial. [ABSTRACT FROM AUTHOR]

The pen shell Pinna nobilis is distributed in the northwest area of the Mediterranean and the Aegean Sea. In this study, on September 9, 2020, one specimen of Pinna nobilis was observed during scuba diving at 16 m depth from Samandag coast (36.259444° N, 35.810111° E) in the northeastern Mediterranean. In this region, the presence of P. nobilis has never been previously recorded, and this new record confirms the presence of a new location in the northeastern Mediterranean Sea. [ABSTRACT FROM AUTHOR]

The first morphologic and genetic documentation of the short-beaked garfish Belone svetovidovi Collette & Parin, 1970 from the coast of the Marmara Sea (Yalova) and Black Sea (Akcakoca) is reported in the present study. The morphological characters and genetic (mtDNA COI) analyses confirmed the existence of this species both in the Marmara and Black Seas. B. svetovidovi is genetically distinct from the anther species of this genus Belone belone. All morphologic measurements, counts, and colour descriptions of B. svetovidovi agree with its previous descriptions. [ABSTRACT FROM AUTHOR]

A group of schools of striped eel catfish Plotosus lineatus (Thunberg, 1787) was photographed during scuba diving at depths of 10 m and 17 m on 11 July 2022 and on 24 September 2022 from Kızkalesi and Boğsak regions in the Mersin Bay of the Mediterranean coast of Turkey. With the present study, P. lineatus is extending its distribution to the western Mediterranean coastal waters after its first occurrence in 2016 in the İskenderun Bay of Turkish Marine waters. [ABSTRACT FROM AUTHOR]

Since 2014, an invasive alien fish species, lionfish, Pterois miles (Bennett, 1828) has been started to distribute in the Turkish Mediterranean Sea coasts and spread out to the Aegean Sea. In the present study, a Cymothoid fish parasite, Nerocila bivittata (Risso, 1816) is reported from the pectoral fin of P. miles caught from the Gulf of Iskenderun (Northeastern Mediterranean) and Bodrum, Turkey (Aegean Sea Coast). This study is the first record of N. bivittata on lionfish P. miles caught from Gulf of Iskenderun. Key diagnostic characters of N. bivittata, some morphological differences observed between the newly collected material of N. bivittata and its previous descriptions, in addition to newly observed additional characters were presented. [ABSTRACT FROM AUTHOR]

A single specimen of Prostheceraeus roseus was recorded for the first time on 25 April 2019 from the Cevlik coast, Iskenderun Bay (Eastern Mediterranean, Turkey). After, other a single specimen of Tylodina perversa was observed during Scuba diving from the Keldag located within Cevlik (Eastern Mediterranean), at a depth of 12 m on rocky habitat covered with algae. The present finding is the first occurrence of Prostheceraeus roseus and Tylodina perversa from the eastern Mediterranean, Turkey. Although these species are live in the Mediterranean Sea up to date no specimens of these species reported in this easternmost coast of Turkey. [ABSTRACT FROM AUTHOR]

The blue button Porpita porpita (Linnaeus, 1758) was observed for the first time in July 2018 in the Iskenderun Bay, Northeastern Mediterranean coast of Turkey. This is the third record of this species for Turkish marine waters, while it is the first record for Iskenderun bay. The presence of P. porpita in the northeastern Mediterranean coast of Turkey shows its extension from northwestern Mediterranean coast (Antalya Bay) of Turkey. [ABSTRACT FROM AUTHOR]

This study is performed to classify fish species based on morphometric measurements between main points (fins, head and mouth) on fish image. Three species of Triglidae Family (Aspitrigla cuculus, Chelidonichthys lastoviza and Chelidonichthys lucernus) which has very similar in appearance of shape, color and the fin type are used for the classification. In the first stage, dataset was collected using images of fish species, and then morphometric features were extracted from the fish images using 13 landmarks. Deep Belief Networks is used as a classifier by combining with 3-fold cross validation method. Consequently, 3 fish-species of Triglidae family are separated with a high accuracy rate of 97.61%. [ABSTRACT FROM AUTHOR]