Fifty years ago, the Baltic population of grey seals was unquestionably in trouble, so much so that they were considered by many to be an endangered species. In the last month, however, a group of ornithologists came across a record herd on the island of Sobieszewo, demonstrating in no uncertain terms that numbers have bounced back!
Members of the KULING Waterbird Research Group had been surveying the Mewia Lacha conservation area at the mouth of the River Vistula when they encountered the seals basking in great numbers and decided to carry out an impromptu headcount. The total arrived at was 165 individuals, making it the largest recorded herd in modern-day Poland.
"We counted approximately 150 seals lying on a sandbar, and there were at least 15 in the water,” explains KULING president, Simon Bzoma. "At this time of year the seals don't have to go ashore as often as in the summer, when they moult, so it looks like they were basking not out of necessity, but rather for the purposes of - you could say - socialising.”
"We are really focused on birds, though, and seal observations are more of a side effect of that. In 2006, for the first time in 15 years, crested terns prevailed in Poland. At first they were on the breakwater in the port of Gdynia but a year later, due to the repairs being carried out there, they moved to the reserve at Mewia Lacha. We decided to watch the colony and have been permanently present in the reserve ever since, primarily protecting the birds but at the same time ensuring peace for the seals.”
In spite of such safehavens for the seals, the full population is still nowhere near estimates from the beginning of the 20th century, when they were so abundant that the Baltic was coloquially referred to as "solid seal”. However, taking into consideration the devastating impact of increased industrial and commercial fishing activity in the 1960s/70s, there has clearly been a significant improvement.
"In the 70s, there were barely 3-4000 thousand grey seals in the whole Baltic,” says Professor Krzysztof Skóra, manager of the Marine Station in Hel. „That meant that the Baltic population of this species was extremely endangered. Today we have 32,000 which is better although still scarcely 1/3 of the number 100 years ago. In addition to the grey seals, we also currently have around 10,000 Arctic ringed seals and 600-800 common seals. In comparison, though, the respective populations at the turn of the century were 200,000 and 5000.”
While wildlife sanctuaries and conservation measures have undoubtedly helped to revitalise numbers, Prof. Skóra also points out the role of migration patterns.
"Many of these herds of seals swimming in the Baltic Sea migrate like their prey, which is primarily herring. You could say that they engage in a kind of "culinary journey" because they travel to where they'll find food. Here at the mouth of the Vistula, nature (with the help of fishermen) also provides the seals with trout which are migrating to spawn.”