COMU Journal of Marine Sciences and Fisheries

11-19

Authors: Zafer Tosunoğlu , Vahdet Ünal

In this study, technical, structural and operational characteristics of fishing gears used in small-scale fishery in Gökçeada and the current inventory was compared with that of previous years. Data were obtained by face-to-face interviews with fishermen of Gökçeada in August 2020. Except for a single trawler that started operating in Gökçeada during the 2019-2020 fishing season, all other 38 fishing boats were small-scale vessels. During these years, the total length of gillnets and entangling nets used decreased by 42% compared to a study conducted a decade ago. In recent years, the increase in costs in longline fishing has made the use of vertical lines, specific calamari hand lines, and different types of hand lines and fishing rods more widespread among commercial fishers. The decline in catches during the last decade and even the collapse of some species such as bluefish in recent years directly reflected on the variety and quantity of fishing gears preferred by fishermen. In recent years, lack of bluefish, sardine and chub mackerel was the main reason for the less frequent use of fishing gears in catching these 3 species. In conclusion, declining catch amounts and changing fishing gear preferences in Gökçeada fishing should be considered as indicators to be taken into consideration in terms of overfishing and sustainable fishing. For this reason, for the re-establishment of sustainable fisheries in Gökçeada, it is recommended to adopt the Ecosystem Approaches to Fisheries in Gökçeada fishery which takes into account not only Gökçeada but also its surroundings, evaluates the effects and interactions on a wide geographic scale, and includes all stakeholders in management efforts.

32-41

Authors: Cahide Çiğdem Yığın, Ali İşmen

The present study reports the age, growth, and reproduction parameters of 52 brown rays (Raja miraletus) captured from the Saros Bay (Northern Aegean Sea) between September 2006 -2008. The males and females accounted for 44.2% and 55.8% of the sample, respectively. The males measured 10.5-53.5 cm (disc width, 6.5-32 cm) and the females ranged 25.5-47.7 cm (disc width, 18-30.5 cm) in total length (TL). The equations TW=0.0017*TL3.27 and TW=0.0017*DW3.38 were used to describe the total length-weight and disc width-weight relationships, respectively. The length-at-age data on vertebrae were used to estimate the von Bertalanffy growth equation: L∞ = 62.43 cm, K = 0.28 year−1, t0 = −0.54 year. The maximum age was found to be 4 years for both the males and females.

53-62

Authors: Erhan Mutlu

One specimen of live sharksucker was caught with a bottom trammel net in Taşucu Bay, south-eastern coast of Turkey, at 1 m depth on May, 2021. Meristic parameters were determined by fin ray counts and metric parameters were measured from the photos of the specimen. Excluding the recent record in Antalya Gulf, previous records of this species occurred later than May, generally in July in the Mediterranean Sea as well as in the Aegean Sea. The biometrical measurements were different in Taşucu Bay compared to those caught from the Aegean Sea and the central Mediterranean Sea (Tunisian and Sicilian waters), but relatively similar to those reported from Croatia. Major discriminative variables, albeit less significant in individuals from the central Mediterranean, were the number of anal, pectoral and dorsal fin rays. Numbers of suction disc laminae were higher in individuals from the central Mediterranean Sea and New Zealand than those from the Turkish coasts (all 21 disc laminae). The statistical analyses (Principal Component and Discriminant analyses) affirmed successful use of meristic parameters to differentiate the biometric characteristics of the species from the Aegean Sea, the central and eastern Mediterranean Sea. The length-weight relationship showed that the species had a negative allometric growth.

71-78

Authors: Melis Yılmaz , Sezginer Tunçer

In this study, Pb, Cu, Zn, Cd and Fe levels in the gonads of Paracentrotus lividus and Arbacia lixula collected from the coasts of Gökçeada were determined seasonally between 2014-2015. Trace element concentrations of P. lividus from highest to lowest ranked as Zn> Fe> Cu>Pb>Cd. Trace element concentrations of A. lixula gonads from highest to lowest ranked as Fe> Zn>Cu>Pb> Cd. Trace element concentrations were statisticaly different between species and between stations and seasons. For comparison purposes in biomonitoring studies only trace element concentrations in identical tissues of sea urchins should be used. Among body tissues, gonads are recommended to be considered as biomonitor tissues, except during reproductive periods.