Karadeniz'de Demersal Balıklara Ait Av Miktarlarının Trend Analizi

Yıl 2022, , 39 - 44, 31.03.2022

İsmet Saygu

https://doi.org/10.35229/jaes.1060770

Cited By: 2

Öz

Türkiye’de balık avı istatistikleri Türkiye İstatistik Kurumu (TUİK) ve T.C. Tarım ve Orman Bakanlığı koordinasyonunda periyodik olarak toplanıp, global balık avı istatistiklerini toplayıp, ilan eden Birleşmiş Milletler Gıda ve Tarım Örgütüne (FAO) raporlanmaktadır. Av miktarlarının doğruluğu konusunda tartışmalar olsa da, zaman serisi av miktarlarının trendlerinin güvenilir olduğu birçok araştırma ile ortaya konmuştur. Bu yüzden, av istatistikleri, stok değerlendirmeleri ve balıkçılık yönetimi için oldukça değerli bir veri kaynağıdır. Bu çalışmanın amacı, Türkiye’nin Karadeniz bölgesinde baskın olarak yakalanan demersal balık türlerine ait av değerlerinin zamansal değişimlerinin trend analizleriyle incelenmesidir. Bu türler, Mezgit (Merlangius merlangus), Barbun (Mullus barbatus), Tekir (Mullus surmuletus) ve Kalkan (Scophthalmus maximus)’dır. Bu kapsamda, FAO ve TUİK veri tabanlarından elde edilen, 1970 – 2020 yıllarını kapsayan, 50 yıllık bir veri seti ve 2000 – 2020 yıllarını kapsayan, Karadeniz’i batı ve doğu olmak üzere inceleme fırsatı veren, 20 yıllık veri setleri kullanılmıştır. Genel olarak zaman serisi av miktarlarına bakıldığında 1980’li yılların sonunda av miktarlarının pik yaptığı ve sonrasında av miktarlarında kayda değer bir azalma olduğu ve akabinde 2000’li yıllardan sonra miktarların daha stabil kaldığı gözlemlenmiştir. Bu süreç Karadeniz ekosistemi için tanımlanmış trofik dönüşüm süreci ile örtüşmektedir. Trend analizi sonuçlarına göre, Barbun (p<0.001), Kalkan (p<0.001) ve toplam av (p>0.05) negatif trend gösterirken, Tekir (p<0.05) ve Mezgit (p>0.05) pozitif trend göstermişlerdir. Karadeniz’in doğu kısmında kayda değer bir alan dip trol balıkçılığı için yasak olmasına rağmen, Mezgit ve Barbun gibi çoğunluğu dip trolü ile yakalandığı bilinen türlerin sırasıyla %75’inin ve %59’unun bu bölgeden rapor edilmesi, Sinop ve Ordu arasında trol sahasının öneminin altını çizmektedir.

Anahtar Kelimeler

Barbun, Kalkan, Mezgit, Tekir.

Trend Analysis of Demersal Fish Landings in the Black Sea

Öz

Fishing statistics in Turkey is periodically collected under the coordination of Turkish Statistical Institute (TUIK) and the Ministry of Agriculture and Forestry, and reported to the Food and Agriculture Organization of the United Nations (FAO), which collects and announces global fishing statistics. Although there are debates about the accuracy of catch amounts, it has been demonstrated by many studies that the trends of time series catch amounts are reliable. Therefore, catch statistics are crucial data source for stock assessments and fisheries management. Using trend analysis, the aim of this study is to investigate the temporal changes of catch values of demersal fish species, which are predominantly caught in the Black Sea region of Turkey. These species are Whiting (Merlangius merlangus), Red Mullet (Mullus barbatus), Surmullet (Mullus surmuletus) and Turbot (Scophthalmus maximus). In this context, a 50-year data set covering the years 1970 - 2020, obtained from the FAO and TUIK databases, and 20-year data sets covering the years 2000 - 2020, giving the opportunity to examine the Black Sea as western and eastern, were used. Results showed that the catch amounts peaked at the end of the 1980s, decreased in the following years and then remained more stable after the 2000s. This story coincides with the trophic transformation process defined for the Black Sea ecosystem. According to the trend analysis results, Red Mullet (p<0.001), Turbot (p<0.001) and total catch (p>0.05) showed a negative trend, while Surmullet (p<0.05) and Whiting (p>0.05) showed a positive trend. Although a significant part of the eastern side of the Black Sea is prohibited for bottom trawling, this area is responsible for significant proportion of the catch of Red Mullet (75%) and Whiting (59%) that remarkably caught by bottom trawlers in the Black Sea. Therefore, results highlight the importance of trawling area between Sinop and Ordu.

Anahtar Kelimeler

Red Mullet, Surmullet, Turbot, Whiting.

Kaynakça

• Akoglu, E., Salihoglu, B., Libralato, S., Oguz, T., & Solidoro, C. (2014). An indicator-based evaluation of Black Sea food web dynamics during 1960–2000. Journal of Marine Systems, 134, 113–125. Doi: 10.1016/j.jmarsys.2014.02.010
• Anonim. (1986). Orta Karadeniz (Sinop-Ünye) Trol Sahalarının Hidrografisi ve Verimliliği.
• Bronaugh, D., & Werner, A. (2019). Zhang + Yue-Pilon Trends Package.
• Çelik Mavruk, N., Mavruk, S., & Avşar, D. (2021). Assessment of goatfish fisheries in Turkey based on the microdata set of official landing statistics. Ege Journal of Fisheries and Aquatic Sciences, 38(3), 303–309. Doi: 10.12714/egejfas.38.3.06
• Coll, M., Shannon, L. J., Kleisner, K. M., Juan-jordá, M. J., Bundy, A., Akoglu, a G., … Shin, Y. (2015). Ecological indicators to capture the effects of fishing on biodiversity and conservation status of marine ecosystems. Ecological Indicators, 60(2016), 947–962. Doi: 10.1016/j.ecolind.2015.08.048
• Demirel, N., Zengin, M., & Ulman, A. (2020). First Large-Scale Eastern Mediterranean and Black Sea Stock Assessment Reveals a Dramatic Decline. Frontiers in Marine Science, 7, 1–13. Doi: 10.3389/fmars.2020.00103
• Friedrich, J., Janssen, F., Aleynik, D., Bange, H. W., Boltacheva, N., Çagatay, M. N., … Wenzhöfer, F. (2014). Investigating hypoxia in aquatic environments: Diverse approaches to addressing a complex phenomenon. Biogeosciences, 11(4), 1215–1259. Doi: 10.5194/bg-11-1215-2014
• Froese, R., Demirel, N., Coro, G., Kleisner, K. M., & Winker, H. (2017). Estimating fisheries reference points from catch and resilience. Fish and Fisheries, 18(3), 506–526. Doi: 10.1111/faf.12190
• Garibaldi, L. (2012). The FAO global capture production database: A six-decade effort to catch the trend. Marine Policy, 36(3), 760–768. Doi: 10.1016/j.marpol.2011.10.024
• Gücü, A. C. (2002). Can Overfishing be Responsible for the Successful Establishment of Mnemiopsis leidyi in the Black Sea? Estuarine, Coastal and Shelf Science, 54(3), 439–451. Doi: 10.1006/ecss.2000.0657
• Hipel, K. W., & McLeod, A. I. (1994). Time Series Modelling of Water Resources and Environmental Systems. Amsterdam: Elsevier.
• Kideys, A. E. (2002). Fall and rise of the Black Sea ecosystem. Science, 297, 1482–1484. Doi: 10.1126/science.1073002
• Knudsen, S., Zengin, M., & Koçak, M. H. (2010). 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. Doi: 10.1016/j.ocecoaman.2010.04.008
• Mavruk, S. (2020). Trends of white grouper landings in the Northeastern Mediterranean: Reliability and potential use for monitoring. Mediterranean Marine Science, 21(1), 183–190. Doi: 10.12681/MMS.18986
• McLeod, A. I. (2015). Kendall rank correlation and Mann-Kendall trend test.
• Mee, L. (2006). Reviving dead zones. Scientific American, 295(5), 78–85.
• Oguz, T. (2007). Nonlinear response of Black Sea pelagic fish stocks to over-exploitation. Marine Ecology Progress Series, 345, 211–228.
• Oguz, Temel. (2017). Controls of multiple stressors on the Black Sea fishery. Frontiers in Marine Science, 4, 1–12. Doi: 10.3389/fmars.2017.00110
• Oguz, Temel, Akoglu, E., & Salihoglu, B. (2012). Current state of overfishing and its regional differences in the Black Sea. Ocean and Coastal Management, 58, 47–56. Doi: 10.1016/j.ocecoaman.2011.12.013
• Oguz, Temel, & Gilbert, D. (2007). Abrupt transitions of the top-down controlled Black Sea pelagic ecosystem during 1960-2000: Evidence for regime-shifts under strong fishery exploitation and nutrient enrichment modulated by climate-induced variations. Deep-Sea Research Part I: Oceanographic Research Papers, 54(2), 220–242. Doi: 10.1016/j.dsr.2006.09.010
• Pauly, D., & Christensen, V. (1995). Primary production required to sustain global fisheries. Nature, 374, 255–257.
• Pauly, D., Christensen, V., Dalsgaard, J., Froese, R., & Torres, J. F. (1998). Fishing down marine food webs. Science, 279(5352), 860–863. Doi: 10.1126/science.279.5352.860
• Resmi Gazete. (2020). 5/1 Commercial Fishery Regulation Rescripts of Republic of Turkey (No: 2020/20).
• Salihoglu, B., Arkin, S. S., Akoglu, E., & Fach, B. A. (2017). Evolution of Future Black Sea Fish Stocks under Changing Environmental and Climatic Conditions. Frontiers in Marine Science, 4(November 2017), 1–19. Doi: 10.3389/fmars.2017.00339
• Sen, P. K. (1968). Estimates of the Regression Coefficient Based on Kendall’s Tau. Journal of the American Statistical Association, 63(324), 1379–1389.
• Shiganova, T. A., & Bulgakova, Y. V. (2000). Effects of gelatinous plankton on Black Sea and Sea of Azov fish and their food resources. ICES Journal of Marine Science, 57, 641–648. Doi: 10.1006/jmsc.2000.0736
• Sullivan, M. G. (2003). Exaggeration of Walleye Catches by Alberta Anglers. North American Journal of Fisheries Management, 23(2), 573–580.
• Tokaç, A., Gücü, A. C., & Öztürk, B. (Eds.). (2012). The state of the Turkish fisheries. Publication Number: 34, Türk Deniz Araştırmaları Vakfı (TÜDAV), İstanbul, Türkiye, 516s.
• Ulman, A. (2014). Actual and perceived decline of fishery resources in Turkey and Cyprus: a history with emphasis on shifting baselines. The University of British Columbia. 189s. Vancouver, Canada.
• Ulman, A., Bekişoǧlu, Ş., Zengin, M., Knudsen, S., Ünal, V., Mathews, C., … Pauly, D. (2013). From bonito to anchovy: A reconstruction of Turkey’s marine fisheries catches (1950-2010). Mediterranean Marine Science, 14(2), 309–342. Doi: 10.12681/mms.414
• Ulman, A., & Pauly, D. (2016). Making history count: The shifting baselines of Turkish fisheries. Fisheries Research, 183, 74-79. Doi: 10.1016/j.fishres.2016.05.013
• Watson, R., & Pauly, D. (2001). Systematic distortions in world fisheries catch trends. Nature, 414(6863), 534–536. Doi: 10.1038/35107050