Are there too many dolphins in the Black Sea?

published on 7/4/12 11:34 AM

Photo: Архив

Our parents remember the view of many dolphins in the Black Sea, chased by fishing vessels. Our childhood memories from the end of the 20th century lacked this picture. The beautiful and smart big mammals were already gone. Today dolphins can be seen again along the coastline, but now the situation is a bit different – fishermen blame the dolphins for eating the fish that they live on…

Does it mean that there are too many dolphins in Bulgaria’s aquatory?

The situation is just the opposite, experts say. Yes, dolphins have appeared again in the Black Sea, but their population is critically small. The fact that the fishermen register smaller catch is due to the sad true that the fishing resources of the Black Sea are chronically reducing.

The porpoise dolphin

Three dolphin species live in our sea – the common one, the common bottlenose dolphin and the smallest one – harbour porpoise. The last two species can be seen mainly near the seashore, while the common one lives in open sea. The dolphin tops the food chain in the Black Sea and practically has no natural enemies, besides people, ecologist Dimitar Popov from the Green Balkans NGO says and adds:
“Bulgaria and other Black Sea countries used to have fishing fleets up to 1966 that killed many dolphins,” Mr. Popov reminds. “These mammals’ products were used predominantly for industrial purposes – mainly for fat output and also in stock breeding as a source of bone meal. Scientific data says that in the 1960s the population of cetaceans in the entire Black Sea amounted to 1-2 mln. animals. Later on it dropped drastically and thus a ban was imposed on dolphin hunting. Turkey was the last state to join this ban in 1983. Unfortunately the trend for reducing of cetaceans’ population in the Black Sea has kept even after the implementation of the ban.”

The ceasing of the hunting came too late. It was considered that the absolute minimum of their populations was reached at the end of the 80s and the beginning of the 90s. The main reason pointed: pollution. Four of Europe’s biggest rivers flow in the Black Sea: Danube, Dnieper, Dniester and Don.

“The pollution of the Black Sea is the main reason for the reduction of the fishing sources, which concerns fishermen,” the expert states. “We all know that the area of the Black Sea that has life in it is a relatively thin layer that constantly narrows. This is due to the fact that the issue with Black Sea countries’ waste waters hasn’t been solved yet, along with the one for waters from the big rivers’ basins.”

Doubtlessly Bulgaria has constructed the greatest number of water treatment plants along the coastline, followed by Romania. Being EU member-states these two countries must implement the strict ecological legislation of the Union. However, things are a bit different, regarding the other Black Sea countries – Turkey, Georgia, Ukraine and Russia.

There are no full surveys on the dolphin population in the Black Sea, but it is supposed to consist of 100,000 - 250,000 animals. The biggest concentrations can be observed near the shores of Turkey and Georgia, where the dolphins spend the winter.

What is the number of dolphins in the Bulgaria aquatory?

It is really difficult to say that due to the huge migration of these mammals. However, no more than 1/3 of their overall number crosses our aquatory, since Bulgaria’s coastline is not that long – only 4-500 km. Green Balkans starts a pilot project for gathering of more information on the subject that will last 8 months.

“The idea is expeditions along the southern coastline to be organized for a first time and photographic material to be gathered from the fins of the cetaceans. Thus the first catalogue of the animals, photographed in this part of the sea will be compiled. This identification will be used also for the tracing of their future migration processes. The dorsal fins of the dolphins are photographed and those are something like human fingerprints due to the specific marks of each fin – pigmentation, traces from different bits and injuries etc. However, the quality of the pictures should be really high. The common bottlenose dolphin is the most suitable for this purpose from the three species in the Black Sea, since its dorsal fin is the biggest.”

The bottlenosed dolphin (Afala)

At first the animals, captured on photo will have IDs, but later on those might be named too, the expert explains. The expeditions will be located mainly at the Cape Emine and Maslen Nos headlands since dolphins can be ambushed most easily there. Romanian researchers will do the same in their part of the sea. Practically the only Black Sea country that is ready with its catalogue with photos of dolphins is Ukraine. The idea is the method experimented to be proposed for implementation into the National System for Biological Monitoring, Dimitar Popov from Green Balkans says in conclusion.