By-catch in the commercial beam trawl fishery for Rapa Whelk in the Black Sea


Published: May 23, 2018
Keywords:
Beam trawl rapa whelk by-catch Black Sea
AHMET RAIF ERYASAR
YUSUF CEYLAN
GOKTUG DALGIC
TUNCAY YESILCICEK
Abstract

In this work, the by-catch was investigated in commercial beam trawls used in the rapa whelk (Rapana venosa) fishery, in trials at sea between September 1, 2015 and April 30, 2016. Four commercial boats using beam trawls were chartered and catch data was collected from a total of 87 hauls. Hauls were performed between 7.1–28.3 meters deep for a duration of 20–77 minutes and haul speed varied between 1.4 – 2.7 knots. A total of 28 by-catch species were identified, which amount in average to 11.4% of the total number of specimens in the by-catch. Two different groups were identified in the by-catch (G1: 7-18 m, G2: 19-26 m) according to depth. Although there is a reduction in the amount of by-catch for G2 group, no significant difference was found between groups (p>0.05). According to Generalized Additive Models (GAM) results, the variables affecting the by-catch amount were identified as fishing area, depth, haul duration, and amount of captured rapa whelk (p<0.01). In addition, a large proportion of immature individuals of striped venus clams (Chamelea gallina), blood cockles (Anadara kagoshimensis), Mediterranean mussels (Mytilus galloprovincialis) and wedge clams (Donax trunculus) were caught as by-catch during the study. Finally, the impact of commercial beam trawls on the demersal macrofauna is discussed.

Article Details
  • Section
  • Research Article
Downloads
Download data is not yet available.
Author Biographies
AHMET RAIF ERYASAR, Recep Tayyip Erdogan University
Vocational School of Technical Sciences, Underwater Technology Program
YUSUF CEYLAN, Recep Tayyip Erdogan University
Faculty of Fisheries
GOKTUG DALGIC, Recep Tayyip Erdogan University
Faculty of Fisheries
TUNCAY YESILCICEK, Recep Tayyip Erdogan University
Faculty of Fisheries
References
Akbulut, B., Kutlu, S., Zengin, M., Aksungur, N., Özkan, B. et al., 2012. TR90 Doğu Karadeniz Bölgesi Su Ürünleri Sektör Raporu. TR90/11/DFD/21, Su Ürünleri Merkez Araştırma Enstitüsü, 107 pp. (In Turkish).
Altınağaç, U., Ayaz, A., Kara, A., 2004. A preliminary study on the whelk fisheries [Rapana venosa (Valenciennes, 1846)] using liftnets of various sizes. Ege Journal of Fisheries and Aquatic Sciences, 21 (3-4), 295-299 (In Turkish).
Anonymous, 2016. The commercial fish catching regulations in seas and inland waters in 2016–2020 fishing period: circular No.2016/35 (in Turkish). Ministry of Food, Agriculture and Livestock, General Directorate of Conservation and Inspection, Ankara, Turkey, 68 pp. (In Turkish).
Bilecik, N., 1975. La Repartition de Rapana thomasiana thomasiana (Grosse) sur le Littoral Turc de la Mer Noire s’etendant d’Ieada jusqu’a Çaltı Burnu. Rapports et Procès-verbaux des Réunions, Commission Internationale pour l'Exploration Scientifique de la Mer Méditerranée, 23 (2), 169-171.
Bök, T.D., Göktürk, D., Kahraman, A.E., 2011. Bycatch in 36 and 40 mm PA Turkish twin rigged beam trawl codends. African Journal of Biotechnology, 10 (37), 7294-7302.
Broadhurst, M.K., Millar, R.B., Kennelly, S.J., Macbeth, W.G., Young, D.J et al., 2004. Selectivity of conventional diamond- and novel square-mesh codends in an Australian estuarine penaeid-trawl fishery. Fisheries Research, 67, 183-194.
Ceylan, Y., Sahin, C. Kalaycı, F., 2014. Bottom trawl fishery discards in the Black Sea coast of Turkey. Mediterranean Marine Science, 15 (1), 156-164.
Clarke, K.R., 1993. Non-parametric multivariate analyses of changes in community structure. Australian Journal of Ecology, 18, 117-143.
Çelik, O., Samsun, O., 1996. Investigation of the catch amount and the catch composition of dredges with various design features. Ege Journal of Fisheries and Aquatic Sciences, 13, 259-272 (In Turkish).
Eryaşar, A.R., Özbilgin, H., Gücü, A.C., Sakınan, S., 2014a. Marine debris in bottom trawl catches and their effects on the selectivity grids in the north eastern Mediterranean. Marine Pollution Bulletin, 81, 80-84.
Eryaşar, A.R, Özbilgin, H., Gökçe, G., Özbilgin, Y.D, Saygu, I. et al., 2014b. The effect of codend circumference on selectivity of hand-woven slack knotted codend in the north eastern Mediterranean demersal trawl fishery. Turkish Journal of Fisheries and Aquatic Sciences, 14, 463-470.
FAO, 2016. The State of Mediterranean and Black Sea Fisheries. General Fisheries Commission for the Mediterranean. Rome, Italy, xiv +, 134 pp.
Gaspar, M.B., Chicharo, L.M., 2007. Modifying Dredges to Reduce By-catch and Impacts on the Benthos. p. 95-140. In: Bycatch Reduction in the World’s Fisheries. Kennelly, S.J. (Ed.). Springer.
Gücü, A.C., 2012. Impact of depth and season on the demersal trawl discard. Turkish Journal of Fisheries and Aquatic Sciences, 12, 817-830.
Janssen, R., Knudsen, S., Todorova, V., Hoşgör, A.G., 2014. Managing Rapana in the Black Sea: Stakeholder workshops on both sides. Ocean and Coastal Management, 87, 75-87.
Kaykaç, M.H., Zengin, M., Özcan-Akpınar, İ., Tosunoğlu, Z., 2014. Structural characteristics of towed fishing gears used in the Samsun coast (Black Sea). Ege Journal of Fisheries and Aquatic Sciences, 31 (2), 87-96 (In Turkish).
Kelleher, K., 2005. Discards in the World’s Marine Fisheries. Food and Agriculture Organization (FAO), FAO Fisheries Technical Paper No 470, 131 pp.
Knudsen, S., Zengin, M., Koçak, M.H., 2010a. Identifying drivers for fishing pressure. A multidisciplinary study of trawl and sea snail fisheries in Samsun, Black Sea coast of Turkey. Ocean and Coastal Management, 53 (5-6), 252-269.
Knudsen, S., Koçak, M.H., 2010b. Through boom and bust: coping with poverty in sea snail fisheries on the Turkish Black Sea coast. p. 221-249. In: Poverty Mosaics: Realities and Prospects in Small-Scale Fisheries. Jentoft, S., Eide, A. (Eds.). Springer Media B.V.
Konsulova, T., Todorova, V., Konsulov, A., 2001. Investigations on the effect of ecological method for protection against illegal bottom trawling in the Black Sea –Preliminary results. Rapports de la Commission Internationale pour l’Exploration Scientifique de la Mer Méditerranée 36, 287 pp.
Kruskal, J.B., Wish, M., 1978. Multidimensional Scaling. Sage Publications, Beverly Hills, CA, 96 pp.
Machias, A., Vasilopoulou, V., Vatsos, D., Bekas, P., Kallianotis, A., Papaconstantinou, C., Tsimenides, N., 2001. Bottom trawl discards in the north-eastern Mediterranean Sea. Fisheries Research, 53, 181-195.
Özbilgin, H., Gökçe, G., Özbilgin, Y.D., Eryaşar, A.R., Bozaoğlu, A.S. et al., 2013. Investigations to improve species and size selectivity in Mersin Bay trawl fisheries. The Scientific and Technological Research Council of Turkey (TUBITAK), Project No: 109O684, Final Report, Mersin, 250 pp. (In Turkish).
Pranovi, F., Raicevich, S., Franceschini, G., Torricelli, P., Giovanardi, O., 2001. Discard analysis and damage to non-target species in the “rapido” trawl fishery. Marine Biology, 139, 863-875.
R Development Core Team, 2013. R: a language and environment for statistical computing. R Foundation for statistical Computing, Vienna <http://www.rproject.org>.
Sağlam, H., Düzgüneş, E., Kutlu, S., Dağtekin, M., Başçınar, S. et al., 2008. Deniz Salyangozu Avcılığında Direçe Alternatif Farklı Tuzak Modellerinin Geliştirilmesi. Su Ürünleri Merkez Araştırma Enstitüsü Müdürlüğü, Trabzon, 90 pp. (In Turkish).
Sanchez, P., Demestre, M., Martin, P., 2004. Characterization of the discards generated by bottom trawling in the Northwestern Mediterranean. Fisheries Research, 67, 71-80.
Şahin, C., Düzgüneş, E., Okumuş, İ., 2006. Seasonal variations in condition index and gonadal development of the introduced blood cockle Anadara inaequivalvis (Bruguiere, 1789) in the southeastern Black Sea coast. Turkish Journal of Fisheries and Aquatic Sciences, 6, 155-163.
Salomidi, M., Katsanevakis, S., Borja, Á., Braeckman, U., Damalas, D. et al., 2012 Assessment of goods and services, vulnerability, and conservation status of European seabed biotopes: a stepping stone toward ecosystem-based marine spatial management. Mediterranean Marine Science, 13(1), 49-88.
Tsagarakis, K., Palialexis, A., Vassilopoulou, V., 2014. Mediterranean fishery discards: review of the existing knowledge. ICES Journal of Marine Science, 71, 1219-1234.
Tudela, S., 2004. Ecosystem effects of fishing in the Mediterranean: an analysis of the major threats of fishing gear and practices to biodiversity and marine habitats. FAO, GFCM Studies and Reviews, 74, Rome, 58 pp.
Türkstat, 2013. Fishery Statistics, Ankara, Turkey.
Valdemarsen, J.W., Suuronen, P., 2003. Modifying fishing gear to achieve ecosystem objectives. p. 321–341. In: Responsible fisheries in the marine ecosystem. Sinclair, M. and Valdimarsson, G. (Eds.). FAO.
Yonge, C.M., 1976. The 'mussel' form and habit. P. 1-12. In: Marine mussels: their ecology and physiology. Bayne, B.L. (Ed.). International Biological Programme.
Zengin, M., Gümüş, A., Süer, S., Van, A., Rüzgar, M. et al., 2014. Assessing trawling impact in regional seas (Black Sea Case Study). Benthis Deliverable 7. 6, Study Report, June, 25 pp.
Zolotarev V,. 1996, The Black Sea ecosystem changes related to introduction of new mollusc species. Marine Ecology, 17, 227-236.
Most read articles by the same author(s)