Sedat Gündoğdu

Micro- and mesoplastics in Northeast Levantine coast of Turkey: The preliminary results from surface samples

The determination of the microplastic distribution will be beneficial as a measure of the potential effects on the environment. The Mediterranean Sea had a high risk of pollution as it was enclosed by highly populated and industrialized countries. Here, we determined the level of micro- and mesoplastic pollution in Iskenderun and Mersin Bays, located in the Northeastern Levantine coast of Turkey. The average level of both micro- and mesoplastic was determined to be 0.376 item/m2 at seven stations. The highest level was determined in Mersin Bay at the mouth of the Seyhan river (Station no. 7, with 906 items), and the lowest level was found in Station no. 4 in Iskenderun Bay (78 items). As a result of this study, it was determined that the microplastic pollution level in the Mediterranean coast of Turkey was similar to the other regions of the Mediterranean Sea.

Fouling assemblage of benthic plastic debris collected from Mersin Bay, NE Levantine coast of Turkey

The Mediterranean is an ecosystem that faces more and more microplastic pollution every day. This causes the whole of the Mediterranean to face the negative effects of plastic pollution. This study examines the state of plastic debris and fouling organisms found on it in one of the areas most affected by plastic pollution, Mersin Bay. As a result, a total of 3.88kg plastic (mean=0,97kg; n=120; 2670item/km2; 86,3kg/km2) was collected and based on the ATR-FTIR analysis, it was determined that this total contained 9 types of plastics. 17 different fouling species belonging to 6 phylum (Annelida, Arthropoda, Bryozoa, Chordata, Cnidaria, Mollusca) 7 class and 11 order were discovered on plastics. Spirobranchus triqueter, Hydroides sp. and Neopycnodonte cochlear were the most abundant species. In the end, the example of Mersin Bay shows that plastic debris as a substrate can contain a very high diversity of life just like natural substrates.

How microplastics quantities increase with flood events? An example from Mersin Bay NE Levantine coast of Turkey

Floods caused by heavy rain carry significant amounts of pollutants into marine environments. This study evaluates the effect of multiple floods that occurred in the northeastern Mediterranean region in Turkey between December 2016 and January 2017 on the microplastic pollution in the Mersin Bay. Sampling was repeated in four different stations both before and after the flood period, and it was determined that in the four stations, there was an average of 539,189 MPs/km2 before the flood, and 7,699,716 MPs/km2 afterwards, representing a 14-fold increase. Fourteen different polymer types were detected in an ATR FT-IR analysis, eight of which were not found in samples collected before the floods. The most common polymer type was identified as polyethylene both pre- and post-flood. The mean particle size, which was 2.37 mm in the pre-flood period, decreased to 1.13 mm in the post-flood period. A hydrodynamic modeling study was implemented to hindcast the current structure and the spatial and temporal distributions of microplastics within the study area. In conclusion, heavy rain and severe floods can dramatically increase the microplastic levels in the sea.

New Record of the Big-Scale Sand Smelt Atherina boyeri Risso, 1810 (Atherinidae) in the Seyhan Dam Reservoir (Seyhan River Basin, Turkey)

Fifteen specimens of the big-scale sand smelt, Atherina boyeri were caught by a single trawl haul with a net mesh size of 3 mm on February 2017 from the Seyhan Dam Reservoir (South Anatolia, Adana/Turkey). In this study the big-scale sand smelt, A. boyeri, was recorded for the first time in the Seyhan Dam Reservoir. In addition, some morphometric and meristic measurements of A. boyeri were given and these values were compared to populations in two different lakes. Furthermore, the possible ecological effects of A. boyeri on Seyhan Dam Reservoir were briefly discussed.

A REVIEW ON GROWTH OF SOME DIPLODUS SPECIES DISTRIBUTED WORLDWIDE

Estimation of the growth parameters of fish are vital to understand their biology. For this purpose we collected studies that performed up to 2017 regarding the growth of species belonging to the Diplodus genus. Data were gathered from sources like Web of Science (webofknowledge.com), Scopus (scopus.com), Google Scholar (scholar.google.com), Researchgate (researchgate.com) and Academia (academia.edu). 79 datasets from 52 different studies belongs to 10 species were compiled. Reviewed studies were published between 1982 - 2017 and were performed in 26 different regions. It was determined that the most frequently studied species was D. vulgaris (n=23). Among growth parameters, it was determined that there is a negative relationship between K and L ∞ , and K and t max , there is a positive relationship between L ∞ and L max . It was also found that there is a negative relationship between K and L ∞ vs latitude.

Age at maturity of some fish species distributed in Turkish marine waters (Actinopterygii and Elasmobranchii)

We collected data on the age at maturity (tm) and maximum reported age (tmax) for 153 stocks of marine fishes in Turkey, belonging to 59 species, 24 families and 2 classes (Actinopterygii and Elasmobranchii). Among Actinopterygii tm had an average of 1.8 years (1 to 4 years) while among Elasmobranchii it had an average of 11.9 years (2 to 11.9 years). Overall, tmax ranged between two years (for Sarda sarda) and 34 years (for Squalus acanthias). Mean tmax was found to be 6.24 years for Actinopterygii and 10.11 years for Elasmobranchii. tm showed a positive linear correlation with tmax for both Actinopterygii and Elasmobranchii. Mean tm⁄tmax did not differ significantly with sex within the Actinopterygii and Elasmobranchii. The ratio tm⁄tmax was found to be significantly lower for Actinopterygii than for Elasmobranchii.

Farklı parametrizasyon tekniklerinin Saurida lessepsianus (Russell, Golani & Tikochinski, 2015)’un von Bertalanffy büyüme parametrelerinin tahminine etkisi

Bu calismada Saurida lessepsianus ’un von Bertalanffy buyume modeli parametreleri tahminine, farkli parametrizasyon tekniklerinin etkisi incelenmistir. Bu amacla Galucci ve Quinn parametrizasyonu, Mooij parametrizasyonu, Francis parametrizasyonu ve Schnute parametrizasyonu kullanilmistir. Akaike Bilgi Kriteri (AIC), guvenirlik araliklari ve parametreler arasi korelasyonlar yardimiyla modeller karsilastirilmistir. Buna gore en uygun parametrizasyon yonteminin Francis parametrizasyon yontemi oldugu tespit edilmistir.

Bayesian Update For Descriptive Statistics In Fisheries Science

Abstract In the present paper we have examined Bayesian update for descriptive statistics for a sample of 730 Por’s Goatfish (Upeneus pori) (Ben-Tuvia and Golani, 1989), collected from Iskenderun Bay, in the northeast Mediterranean Sea. The computational approach uses the Markov Chain Monte Carlo simulation to draw samples from the posterior distributions of model parameters implementing the simulation in OpenBUGS software. We assigned the results of previous studies as a prior distribution. The posterior distribution for mean length and variance were found to be 11.1 cm and 0.003, while for weight, they were 15.7 g and 0.026. The 95% confidence limits of length and weight were 10.99-11.21 and 15.42-16.05 respectively. The key aspect of this research is that when previous studies are included in the estimation, this significantly reduces the variance and uncertainty, leading to a more sufficient and reliable estimation.