Terms of reference for the mediterranean tuna habitat observatory initiative

[EN] We present the Terms of Reference for a case study on a Mediterranean eco-region focusing on the environmental component of the Ecosystem Report Card. The objective of this case study is to describe and monitor the variability of environmental processes in the Mediterranean Sea that affect the ecology of large pelagic fishes, with a particular attention on tunas, and the possible role of climate change on this variability. Here we define the objectives and activities of the initiative, the participant roles, primary indicators and the methodological approach[FR] Ce document présente les termes de référence d’une étude de cas sur une écorégion méditerranéenne consacrée à la composante environnementale de la fiche informative sur les écosystèmes. L'objectif de cette étude de cas est de décrire et de suivre la variabilité des processus environnementaux en mer Méditerranée qui affectent l'écologie des grands poissons pélagiques, en accordant une attention particulière aux thonidés, et de déterminer le rôle possible du changement climatique sur cette variabilité. Nous définissons ici les objectifs et les activités de l'initiative, les rôles des participants, les indicateurs primaires et l'approche méthodologique.[ES] En el documento se presentan los términos de referencia para un estudio de caso sobre una ecorregión mediterránea centrado en el componente medioambiental de la ficha informativa sobre ecosistemas. El objetivo de este estudio de caso es describir y hacer un seguimiento de la variabilidad de los procesos medioambientales en el mar Mediterráneo que afectan a la ecología de los grandes peces pelágicos, con especial atención a los túnidos, y el posible papel del cambio climático en esta variabilidad. A continuación, se definen los objetivos y actividades de la iniciativa, las funciones de los participantes, los indicadores principales y el enfoque metodológico.Peer reviewe

Temporal changes in ichthyoplankton abundance and composition of Babadillimani Bight: Western entrance of mersin bay (Northeastern Mediterranean)

In this study the temporal changes in ichthyoplankton abundance and composition of Babadi{dotless}llimani{dotless} Bight (Northeastern Mediterranean) were identified and simultaneously the spawning periods of sampled teleost fishes were observed. Thus, monthly samplings were performed at nine stations by using Hensen Net with 300µm mesh size during one year period between May 1999 and April 2000. Throughout the studying period, early life stages of 23 teleost fish species were observed. The mean egg and larval abundance were calculated as 46, and 20 individual 10m-3 respectively. While the maximal egg abundance was observed in summer, larval abundance was the highest in early autumn. Only temporal changes in egg abundance (P<0.01) were significant; however spatial-temporal changes in larval abundance were not. Shannon-Wiener Diversity Index values were obtained as highest in summer for eggs, and in autumn for larvae as also being abundance. © Published by Central Fisheries Research Institute (CFRI) Trabzon, Turkey in cooperation with Japan International Cooperation Agency (JICA), Japan

Warming in Turkish seas: Comparative multidecadal assessment

Although sea temperature characteristics and their variations in the Mediterranean and Black Seas have been studied at length over the course of different time periods and varied areas of spatial coverage, there remains no specific evaluation of Turkish Seas. This study provides an assessment of sea surface temperatures during a period between September 1981 and December 2014; conducted in order to understand characterization of the basic features and to enable description of linear and non-linear inter-annual patterns in Turkish seas: the northern Levantine Sea, the eastern Aegean Sea, the Marmara Sea and the southern Black Sea. The results of our study showed that there are significantly positive trends in all of the aforementioned regions, and that the rate of warming in the two colder basins, the Black Sea and the Marmara Sea, was detected to be higher than the rate discovered found in the Aegean Sea and Levantine Sea. © 2019, Central Fisheries Research Inst. All right reserved

Non-native fishes in the Mediterranean from the Red Sea, by way of the Suez Canal

The opening of the Suez Canal in 1869 caused a migration generally from the Red Sea to the Mediterranean, rarely the opposite direction, and 63 lessepsian fish species penetrated into the Mediterranean by way of this canal. These species usually spread northward and most of them can establish wide populations in this area, but some of them can not be successful with respect to establishment. Thus, it is clearly seen that there are a lot of factors influencing the success of species with respect to migration, spreading and establishment. So, the lessepsian migration has been formed by the effects of these factors. Lessepsian species also have the ability to adapt to the ecological conditions of their new environment. Therefore, the influential factors, their effectiveness and the observed changes in lessepsian species due to the effects of these factors have been discussed by considering fishes in this paper. © Springer Science+Business Media B.V. 2008.CIESM International Commission for the Scientific Exploration of the Mediterranean Sea EEA European Environment Agency TUDAV Turkish Marine Research Foundatio

The rate and causes of the loss of gill and trammel nets in Iskenderun Bay (north-eastern Mediterranean)

Summary: The aim of this study was to detect the rate and causes of loss of shrimp trammel nets, sole trammel nets and other gill and trammel nets during one fishing season in Iskenderun Bay, Turkey. Interviews with the captains of 127 fishing boats between November 2007 and November 2008 revealed the average effective loss rate per fishing boat for shrimp trammel nets, sole trammel nets and other gill and trammel nets as 4.33±0.54, 5.35±0.89 and 3.33±0.34 panels, respectively, with a total loss of 723, 636 and 663 panels, respectively. The most common reason for shrimp and sole trammel net loss was conflict with other fishing gear; bad weather conditions were also reported as important reasons for losses of other gill and trammel nets. © 2012 Blackwell Verlag, Berlin

Effects of predator size and gonad maturation on food preference and feeding intensity of Sander lucioperca (linnaeus, 1758) [Sander lucioperca (linnaeus, 1758)'da predatör boyu ve gonad gelişiminin besin tercihi ve beslenme yogunluguna etkisi]

This study examines temporal changes and predator size-dependent changes in the important dietary groups and feeding intensity of pikeperch Sander lucioperca. Monthly experimental fishing operations were conducted for sampling purposes using gillnets with different mesh sizes between July 2009 and June 2010. The results showed significant changes in the important dietary items as a function of predator size. Diptera and mysids were the most important groups for pikeperch smaller than 19 cm, whereas fish were most important for pikeperch larger than 19 cm. The important dietary items also varied significantly over time. The most important dietary groups were mysids during December, January and February; diptera during March and April; and teleosts during the other months. The feeding intensity of pikeperch peaks in October and March and then progressively decreases between October and February. The decrease in feeding intensity was related to the reproductive period. © Published by Central Fisheries Research Institute (CFRI) Trabzon, Turkey

First record of the indo-pacific burrowing goby Trypauchen vagina (Bloch and Schneider, 1801) in the north-eastern Mediterranean Sea

This paper presents the first observation of a recent Lessepsian fish species, the burrowing goby, Trypauchen vagina (Bloch and Schneider, 1801) in the North-Eastern Mediterranean Sea, where two specimens of burrowing goby were caught by a shrimp trammel net in Iskenderun Bay. This record indicates the range extension of a possibly established population of burrowing goby in the Eastern Levant Basin. © 2011 The Author(s)

Spawning, maturity length and size selectivity for pikeperch (Sander luciopercd) in Seyhan Dam lake

This study was conducted in Seyhan Dam lake between June 2007-2008. About 778 pikeperch (Sander lucioperca, Percidae) individuals were examined by means of monthly sampling and their spawning times and first sexual maturity lengths were determined. The findings obtained displayed that pikeperch in Seyhan Dam lake spawned after the month of February and the male and the female pikeperch reached the first maturity lengths of 256 mm TL (206 mm SL) and 264 mm TL (216 mm SL), respectively. Furthermore, the size selectivities of the pikeperch were estimated by using monofilament gillnets with mesh openings of 40, 44, 48 and 52 mm. For the estimation of size selectivity, the lowest deviation value was observed for the log-normal model among the selectivity curves drawn by using normal location, normal scale, log normal, gamma and bimodal distributions. © Medwell Journals, 2011

Conjoined twinning incidences in trachurus mediterraneus (Steindachner, 1868) eggs in Southern Marmara sea [Marmara denizi’nin güneyinde trachurus mediterraneus (steindachner, 1868) yumurtalarına ait yapışık İkiz gözlemleri]

Conjoined twinning is a rarely existed gross malformation in natural conditions. The term refers to the two individuals united at any part of their bodies. The extraordinary incidences of conjoined twinning cases may reflect important problems on the marine environment. Therefore, the purposes of this study were to report the incidences of Trachurus mediterraneus conjoined twins in Bandırma Bay, Southern Marmara Sea and to discuss the possible causes of them to derive new research questions. Four polyembryonic individuals were collected from three stations of Bandırma Bay Ichthyoplankton Survey in June 2012. The anomalous individuals were observed at the stations, St-9, 10 and 13 (Critical Stations). St-9 was at about 20m depth contour between Karşıyaka town and Dalyan village in western coasts of bay. St-10 and 13 was off Yenice village at about 10 and 30m depth contoursrespectively in the eastern coasts of the bay. The surface temperature, salinity, dissolved oxygen and pH of critical stations were seemed to be normal. Therefore the pollution was considered as the most possible reason of these incidences. © Published by Central Fisheries Research Institute (CFRI) Trabzo

Spawning ecology of Pegusa lascaris in Iskenderun Bay (Northeastern Mediterranean Sea)

The aim of this study was to determine the spawning season, spawning area, and length at first maturity of Pegusa lascaris in Iskenderun Bay (Northeastern Mediterranean Sea). For this purpose, experimental trawl operations in parallel with ichthyoplankton surveys were performed from September 2009 to October 2010 with monthly intervals. Both the results of ichthyoplankton surveys and gonado-somatic index examinations showed that spawning of Pegusa lascaris took place from the end of autumn till the beginning of summer (8 months). Throughout this period, there was two spawning peaks which were in Autumn and Spring. The maximum spawning occurred in April. The spatial distribution of P. lascaris eggs revealed that the main spawning ground was located in 0-50 m depth contours. Female length at first maturity was observed as 14.5 cm. © by PSP.This study was supported by the Cukurova University Research Foundation (Project No. SÜF2012YL5)