Exploring the dynamics of small pelagic fish catches in the Marmara Sea in relation to changing environmental and bio-optical parameters

The Marmara Sea has a large drainage basin that includes cities with heavy industrialisation and agricultural land use. Therefore, it is under the influence of significant anthropogenic activities that adversely affect the well-being of its ecosystem. The Marmara Sea is also an important fishing ground with many commercially important fish species. These fish species are also under the influence of the adverse impacts of anthropogenic activities. Fisheries catches in the Marmara Sea had experienced severe fluctuations since the onset of the 2000s. In this study, possible underlying reasons for these fluctuations were investigated between 2000 and 2019 using remotely- sensed environmental and environmentally-influenced bio-optical parameters and fishery statistics. First, long-term inter-annual changes in the time series of sea surface temperature (SST), chlorophyll-a (Chl-a) concentration, net primary productivity (NPP), fishing effort, and catches of commercially important fish species, i.e. anchovy, sprat, Mediterranean and Atlantic horse mackerels and sardine, were scrutinised using trend analysis. Then, relationships between species’ catches and the changes in the SST, Chl-a concentration, NPP, and fishing effort were investigated using correlation analysis. The results of the trend analysis showed that there were statistically significant declines in the catches of Mediterranean horse mackerel, sprat, and the total catch of the investigated species, although the decrease in the fishing effort was statistically not significant. The analysis of relationships between the environmental and bio-optical parameters and fishery statistics indicated that SST had statistically significant negative and NPP had statistically significant positive correlations with the catches of anchovy, sprat, and Mediterranean horse mackerel. Overall, the results indicated that the decreases in the fisheries catches were strongly correlated with the environmental and environmentally-influenced bio-optical parameters and fisheries management practices should consider environmental aspects of the ecosystem in addition to conventional fisheries regulations.

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  • Abaunza P, Gordo L, Karlou-Riga C, Murta A, Eltink AT et al. (2003). Growth and reproduction of horse mackerel, Trachurus trachurus (Carangidae). Reviews in Fish Biology and Fisheries 13 (1): 27-61. doi: 10.1023/A:1026334532390.
  • Antoine D, Morel A (1996). Oceanic primary production: 1. Adaptation of a spectral light‐photosynthesis model in view of application to satellite chlorophyll observations. Global Biogeochemical Cycles 10 (1): 43-55. doi:10.1029/95GB02831.
  • Ayaz SÇ, Aktaş Ö, Dağlı S, Akça L (2012). Point and diffuse sources of pollution and surface water quality in Marmara Basin of Turkey. In: 21st Century Watershed Technology: Improving Water Quality and Environment Conference Proceedings 2012; Bari, Italy. p 50. doi:10.13031/2013.41407.
  • Balık İ (2018). Comparatively evaluation of the Sprat (Sprattus sprattus) fisheries in the whole of the Black Sea and in the Turkish Coast of the Black Sea. Turkish Journal of Maritime and Marine Sciences 4 (1): 52-62.
  • Bayazıt M, Önöz B (2007). To prewhiten or not to prewhiten in trend analysis?. Hydrological Sciences Journal 52 (4): 611-624. doi:10.1623/hysj.52.4.611.
  • Beşiktepe ŞT, Sur Hİ, Özsoy E, Latif MA, Oğuz T et al. (1994). The circulation and hydrography of the Marmara Sea. Progress in Oceanography 34 (4): 285-334. doi:10.1016/0079- 6611(94)90018-3.
  • Bengil F, Mavruk S (2018). Bio-optical trends of seas around Turkey: An assessment of the spatial and temporal variability. Oceanologia 60 (4): 488-499. doi: 10.1016/j. oceano.2018.03.004.
  • Bronaugh D, Werner A (2019). zyp: Zhang + Yue-Pilon Trends Package. R package version 0.10-1.1.
  • Brosset P, Ménard F, Fromentin JM, Bonhommeau S, Ulses C et al. (2015). Influence of environmental variability and age on the body condition of small pelagic fish in the Gulf of Lions. Marine Ecology Progress Series 529: 219-231. doi:10.3354/ meps11275.
  • Carroll JB (1961). The nature of the data, or how to choose a correlation coefficient. Psychometrika 26 (4): 347-372.
  • Chassot E, Mélin F, Le Pape O, Gascuel D (2007). Bottom-up control regulates fisheries production at the scale of eco-regions in European seas. Marine Ecology Progress Series 343: 45-55. doi:10.3354/meps06919.
  • Cleveland RB, Cleveland WS, McRae JE, Terpenning I (1990). STL: A seasonal-trend decomposition. Journal of Official Statistics 6 (1): 3-73.
  • Conti L, Scardi M (2010). Fisheries yield and primary productivity in large marine ecosystems. Marine Ecology Progress Series 410: 233-244. doi: 10.3354/meps08630.
  • Dave AC, Lozier MS (2010). Local stratification control of marine productivity in the subtropical North Pacific. Journal of Geophysical Research Oceans, 115 (C12032): 1-16. doi: 10.1029/2010JC006507.
  • 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: 103. doi:10.3389/fmars.2020.00103.
  • Garnesson P, Mangin A, Bretagnon M (2020). Quality information document for the Ocean Colour Production Centre Satellite Observation Copernicus-GlobColour products. Copernicus Marine Environment Service.
  • Kukul K (1987). Biology of Mediterraneus horse mackerel, Trachurus mediterraneus (Steindachner, 1868), in the İstanbul Strait. MSc, İstanbul University, Institute of Marine Sciences and Management, İstanbul, Turkey (in Turkish).
  • Leitão F, Maharaj RR, Vieira VM, Teodósio A, Cheung WW (2018). The effect of regional sea surface temperature rise on fisheries along the Portuguese Iberian Atlantic coast. Aquatic Conservation: Marine and Freshwater Ecosystems 28 (6): 1351-1359. doi:10.1002/aqc.2947.
  • Lisovenko LA, Andrianov DP (1996). Reproductive biology of anchovy (Engraulis encrasicolus ponticus Alexandrov 1927) in the Black Sea. Scientia Marina, 60: 209-218.
  • Niermann U, Kideys AE, Kovalev AV, Melnikov V, Belokopytov V (1999). Fluctuations of pelagic species of the open Black Sea during 1980–1995 and possible teleconnections. In: Beşiktepe Ş, Ünlüata Ü, Bologa AS (editors). Environmental Degradation of the Black Sea: Challenges and Remedies. NATO Science Series (2. Environmental Security), vol 56. Dordrecht, the Netherlands: Springer, pp. 147-173. doi:10.1007/978-94-011- 4568-8_10.
  • Okay N, Ergün B (2005). Source of the basinal sediments in the Marmara Sea investigated using heavy minerals in the modern beach sands. Marine Geology 216 (1-2): 1-15. doi:10.1016/j. margeo.2005.01.006.
  • Pennino MG, Coll M, Albo-Puigserver M, Fernández-Corredor E, Steenbeek J et al. (2020). Current and future influence of environmental factors on small pelagic fish distributions in the Northwestern Mediterranean Sea. Frontiers in Marine Science 7: 622. doi:10.3389/fmars.2020.00622.
  • R Core Team (2020). R: A Language and Environment for Statistical Computing. Vienna, Austria: R Foundation for Statistical Computing.
  • Ricker WE (1975). Computation and interpretation of biological statistics of fish populations. Ottowa, Canada: Bulletin Fisheries Research Board of Canada.
  • Sabatés ANA, Martín P, Lloret J, Raya V (2006). Sea warming and fish distribution: the case of the small pelagic fish, Sardinella aurita, in the western Mediterranean. Global Change Biology 12: 2209-2219. doi:10.1111/j.1365-2486.2006.01246.x
  • Salihoglu B, Arkin SS, Akoglu E, Fach BA (2017). Evolution of future Black Sea fish stocks under changing environmental and climatic conditions. Frontiers in Marine Science 4: 339. doi:10.3389/fmars.2017.00339.
  • Schaefer MB (1954). Some aspects of the dynamics of populations important to the management of the commercial marine fisheries. Inter-American Tropical Tuna Commission Bulletin 1 (2): 27-56.
  • Shapiro SS, Wilk MB (1965). An analysis of variance test for normality (complete samples). Biometrika 52 (3/4): 591-611.
  • Smith C, Warren M (2019). GLMs in R for ecology. Seattle, WA: Amazon Publishing.
  • Taş S, Ergül HA, Balkıs N (2016). Harmful algal blooms (HABs) and mucilage formations in the Sea of Marmara. In: Turan C, Salihoğlu B, Özgür Özbek, E, Öztürk B (editors). The Sea of Marmara Marine Biodiversity, Fisheries, Conservation and Governance. İstanbul, Turkey: Turkish Marine Research Foundation (TUDAV). pp. 768-786.
  • Teixeira CM, Gamito R, Leitao F, Murta AG, Cabral HN et al. (2016). Environmental influence on commercial fishery landings of small pelagic fish in Portugal. Regional Environmental Change 16 (3): 709-716. doi:10.1007/s10113-015-0786-1.
  • Thorsten P (2020). trend: Non-Parametric Trend Tests and Change- Point Detection. R package version 1.1.4.
  • Tsikliras AC, Koutrakis ET (2013). Growth and reproduction of European sardine, Sardina pilchardus (Pisces: Clupeidae), in northeastern Mediterranean. Cahiers de Biologie Marine 54 (3): 365-374.
  • Ünlüata Ü, Oğuz T, Latif MA, Özsoy E (1990). On the physical oceanography of the Turkish Straits. In: Pratt LJ (editor). The Physical Oceanography of Sea Straits. Dordrecht, the Netherlands: Springer, pp. 25-60.
  • Yue S, Pilon P, Cavadias G (2002). Power of the Mann–Kendall and Spearman’s rho tests for detecting monotonic trends in hydrological series. Journal of Hydrology 259 (1-4): 254-271. doi: 10.1016/S0022-1694(01)00594-7.