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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]

There is a controversy whether Fistularia petimba or F. commersonii are same species or distinct, since it is difficult to distinguish them based on morphological characters. In the present study, the COI and Cyt b gene regions of the mitochondrial DNA were used to address this question as well as to clarify the presence F. petimba. Based on the results, genetic distance between F. petimba and F. commersonii based on COI and Cyt b sequences were found to be 0.9536 and 0.95500, respectively. Average genetic diversity between species based on COI and Cyt b were found to be 0.00487, 0.04651 respectively. According to the results, F. petimba and F. commersonii are found genetically distinct from each other. The occurrence of red cornetfish F. petimba from Turkey marine waters was also confirmed showing its rapid range expansion to the Eastern Mediterranean Sea. [ABSTRACT FROM AUTHOR]

One specimen of Seriola fasciata was caught by a commercial trawler at depths of 60-70m on 10 November 2018 from the Çevlik coast of Turkey Iskenderun Bay. The present paper reports the second record of Seriola fasciata in Turkish Marine waters. [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 examined the age distribution and growth characteristics of the striped eel catfish ( Plotosus lineatus ), which is an invasive alien species in the eastern Mediterranean. A total of 1,011 samples were collected from Iskenderun Bay (Turkey), with lengths ranging from 5.1 to 16.8 cm, predominantly comprising females (1:1.92). Age 3 represented the majority in the population (52.03%). The value of the scaling exponent "b" of the length-weight relationship was less than "3" for both sexes (females: 2.28; males: 2.26; combined: 2.27). The results for the von Bertalanffy growth parameters were observed for the combined sexes as, L ∞ = 24.9934 cm, k = 0.1718 year -1 , and t₀ = -1.7707 years. The striped eel catfish populations in Iskenderun Bay exhibited negative allometric growth patterns and were predominantly composed of adult individuals. This study presents the dataset on the length-weight correlations, age-growth characteristics, and von Bertalanffy growth parameters of Plotosus lineatus in the Mediterranean Sea, thereby significantly contributing to comprehending the stock dynamics. It is anticipated that this study will make a significant contribution to the management of P. lineatus stocks, given its invasive nature., Competing Interests: Servet Doğdu is an Academic Editor for PeerJ., (© 2024 Doğdu and Turan.)