Factors vary for changes in fishing stocks and for Türkiye, it is climate change, maritime pollution, illegal fishing and overfishing, while experts urge authorities to take measures.

Figures released by the Turkish Statistical Institute (TurkStat) show Türkiye managed to exceed 500,000 tons yearly in 2000 in fishery yields, but this number dropped to 364,400 tons in 2020. As a matter of fact, the last time it exceeded 500,000 since 2000 was in 2011 when the yield reached 514,744 tons annually.

Authorities try to address the issue with a set of measures, renewed nearly every year, ranging from regulations on bans to the designation of new fisheries. Most recently, a regulation implemented on Sept. 10 added more species to a list of banned catches while more areas were added to places where fishing is entirely banned.

Eyüp Mümtaz Tıraşın, a member of the Institute of Maritime Sciences and Technology at Dokuz Eylül University of Türkiye, says the most effective measures to protect the fisheries were time-specific bans, bans for certain areas and the formation of "fishery preservation areas" entirely closed to fishing. Tıraşın, who also serves as deputy chair of the Scientific Advisory Committee on Fisheries of the General Fisheries Commission for the Mediterranean (GFCM), says "unfortunately" some fishermen violated bans.

"Industrial fishing methods are banned between April 15 and Sept. 1 in the Aegean, Black Sea and the Marmara Sea and for the Mediterranean, the ban is extended to Sept. 15. All those bans are implemented based on the incubation season of the fish. Yet, fishermen do not comply with bans," he lamented.

Tıraşın told Anadolu Agency (AA) on Friday that more detailed regulations might be needed, based on studies on the mating and incubation season of "critical" species. "We see a tendency for overfishing now. This might have something to do with low income for fishermen but if this is the case, fishermen should be provided financial support. We should reduce the number of fishing boats. Türkiye already has too many fishing in its waters," he said.

Tıraşın added that climate change and increasing seawater temperatures also caused pressure on fisheries and fishing. "Waters are warming and we see chemical changes in the water. This naturally and dramatically affects the fish, all species living in sea," he said. Tıraşın noted that "ecosystem-based fishing" found more support in the world in recent years in light of these developments.

"We can find a solution to this issue with management plans that both preserve the ecosystem and socioeconomic structures of fishing communities, plans that will also secure access to fish for consumers," he said. "For example, fishing boats can be restricted to operate in one sea only. If you fish in the Aegean, you should continue fishing there, instead of heading to the Black Sea (for more fishing activity)."

Pollution is another problem challenging the fishing stocks. "Pollution is more evident in rivers and streams flowing into the sea. Toxic materials mixed in the water can lead to fish deaths. In the open sea, we see a growing threat of microplastics. When consumed by marine species, microplastics may cause death," he said.

Türkiye is home to more than 510 fish species sought by commercial fishermen. Tıraşın says the Aegean Sea has the most, at 449, pointing to a wide gap between the "northern and southern seas" in terms of the number of species. The Black Sea hosts only 154 species. "TurkStat data shows more than 20 species are tracked for commercial fishing, from hamsi to haddock. If new measures are to be taken, fishermen should be consulted," he said. Tıraşın also pointed out that supply and demand determine the price of fish, hence, the rate of consumption. "Consumers should also be cautious not to purchase species banned from hunting. They should not buy fish smaller than the size designated (by the government)," he warned.

Professor Deniz Ayas, a fishing expert from Mersin University, says fishing bans and measures were implemented based on data about the ecosystem. Yet, Ayas added that many species were under threat of extinction due to overfishing. "Many shark species have lost almost 90% of their population," Ayas said. Ayas said fishermen’s choice of fishing tools was also part of the problem. "Trolling does not mean you will catch only one specific species you wanted to hunt. Like many marine animals, sharks are also caught inadvertently during trolling. It places pressure on other species. Sharks, for instance, can give birth to only four offspring a year, while other fish can lay up to 100,000 roes," he said. Ayas noted that more areas should be preserved and any type of fishing should be banned in those places.

"A healthy marine ecosystem also means preservation of land species," he added.