Pelagic Fish Catches in Relation to Chlorophyll-a and Sea Surface Temperature in the Marmara Sea

Year 2025, Volume: 12 Issue: 4, 398 - 407, 12.01.2026

Erdal Tokat

https://doi.org/10.26650/ijegeo.1758240

https://izlik.org/JA46FB97XS

Abstract

Using 21 years of time series data from 2003 to 2023, we examined the correlations between pelagic fish catches and satellite-based chlorophyll-a (Chl-a), sea surface temperature (SST), and fishing effort in the Marmara Sea. Variability and trends in the time series, as well as cross-correlation relationships between the time series, were investigated for the study period. The results showed that the basin-averaged annual mean Chl-a varied notably, peaking in 2003–2004 and 2010–2011. Sea surface temperature (SST) time series showed a statistically significant trend of 0.069 °C per year, with significant decreases recorded in 2011, 2017, and 2022. The percentage of anchovy in the total fish catch increased significantly during the study period. The total fish catch, fishing effort, and the catches of Mediterranean and Atlantic horse mackerel, bluefish, shad, and Atlantic mackerel exhibited statistically significant decreasing trends, with the most pronounced decline observed in Mediterranean horse mackerel. SST showed significant negative correlations with total fish and anchovy catches at a one-year lag, and with Atlantic mackerel without lag, but was positively correlated with Bluefish at a two-year lag. Chl-a had significant positive correlations with total fish and anchovy at a two-year lag, and with Atlantic bonito at a one-year lag. Shad was positively correlated with Chl-a and negatively with SST at a two-year lag. High catch levels observed prior to the marine mucilage events may have contributed to their development.

Keywords

Sea of Marmara , fisheries catch , chlorophyll-a , sea surface temperature

Ethical Statement

We declare that our study do not require ethical committee permission.

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