Polski
Seals at first glance appear to be friendly animals, and their friendly appearance arouses curiosity and interest in tourists. They are herd animals that live an aquatic and terrestrial lifestyle. They regularly go ashore to rest on the beach.
Seals are naturally not aggressive animals toward humans and do not initiate an attack without cause. On the other hand, when they are disturbed, provoked or feel threatened, they may attack in self-defense, which is natural and understandable.
In recent years, however, there have been a growing number of reports of unprovoked, aggressive behavior by seals toward humans, which have been reported, among others. In South Africa in the Cape Town area or in Scotland near Eyemouth[1]. In January of this year, off the coast of Africa, a boy on the beach, in the midst of bathing tourists, was attacked and bitten by a seal. Similar reports have also been received previously, indicating a disturbing change in the behavior of these animals toward humans and requiring further research[2].
In a natural situation, when seals are disturbed or feel threatened, they become skittish, run away and return to the water. Nowadays, we are increasingly seeing individuals who choose to aggressively confront danger. The likely cause is a long-term side effect of domoic acid poisoning. It occurs as a result of eating fish and shellfish contaminated with this toxin, which is released into the marine environment as a result of algal blooms. But lest a person feel guiltless, it is imperative to add that the cause of algal blooms is, among other things. The phenomenon of eutrophication of waters, which is one of the anthropogenic pressures affecting marine ecosystems.
Domoic acid poisoning causes swelling around the heart and brain in marine animals. The most notable effect that has been observed in seals is increased levels of aggression, a neurological side effect of brain swelling. As a result of poisoning, the natural escape response is disrupted, and the animal goes directly into combat[3].
Let’s get to know each other
Let’s move to the Baltic Sea. It is home to three species of seals: gray, ringed and common. The most abundant species on the Polish coast is the gray seal. At the same time, it is the largest among the representatives of this species found in Poland – males grow up to 3 m in length, reaching a weight of 300 kg and are characterized by dark gray coloration. Females are smaller, with a maximum length of 2 meters, and the characteristic feature is a creamy white belly with irregular dark spots. Currently, there are about 40,000 in the Baltic Sea. pieces of this species. In the 20th century, we lost approx. 90% of the gray seal population, as these animals were considered pests and intensively exterminated.
Much rarer on the Polish coast is the ringed seal, the smallest of those found in the Baltic, which numbers 15,000. This Arctic species has established itself in the northern part of the Baltic Sea. The rarest seal species in the Baltic is (contrary to its name) the common seal, which is estimated to be about. 1,000[4].
How does human pressure affect seals?
Seals are exposed to a range of anthropogenic pressures that can disrupt their natural functioning. One of them is the pressure resulting from the intensive development of tourism throughout the coastal area. Seals need access to resting, moulting and breeding areas, which are in short supply on Polish beaches. There are numerous incidents of disturbing, scaring and disturbing the rest of these animals.
Another pressure in the Baltic Sea is undoubtedly underwater noise associated with human activities, which can be divided into two categories: continuous and impulsive. Anthropogenic sources of continuous sound include. Those generated by ships and boats, wind turbines or bridges. Impulse noise is characterized by short duration and rapid pulse buildup (explosions and blasts, seismic testing, piling). Noise affects marine mammals, causing hearing damage, physiological and behavioral changes, in addition to masking biologically important sounds.
Incidental fishing (known as bycatch), that is, seals getting entangled in fishing nets set along their migration route, is also an important pressure on the species. The victims are usually juveniles. Seal bycatch in the Baltic is estimated at approx. 7.5% of the population size.
The seal population is also not indifferent to pollutants introduced into the waters: synthetic and non-synthetic pollutants, radionuclides or waste, as well as eutrophication[5]. The agricultural sector is pointed to as the main culprit for the excessive enrichment of the sea in nitrogen and phosphorus compounds.
Where can you find seals in the Baltic Sea?
The only place in Poland where a colony of wild seals can be found is the Mewia Łacha nature reserve on Sobieszowska Island at the mouth of the Vistula River. It is a resting as well as foraging site that the animals choose regularly due to its considerable seclusion. In the reserve, an information and educational path has been marked along the route, with two viewing platforms from which you can observe seals lounging on sandbanks. In addition, single individuals can be found along the entire Polish Baltic coast, even in popular resorts.
What to do when you meet a seal?
Remember, the seal, like all marine mammals, is a protected species animal. Among other things, it is forbidden to. deliberately killing them, scaring them or destroying their habitat. Anyone who disturbs them – breaks the law.
If you meet a seal on the beach, follow these rules:
- do not approach and leave it alone – it is a wild animal that can bite in a threatening situation; 20 – 30 m is indicated as a safe distance for seal observation;
- let the seal come ashore;
- inform the WWF Blue Patrol (795 536 009) or the UG Marine Station in Hel (601 88 99 40), especially when you are concerned about the seal’s behavior or condition – specialists will suggest what to do and collect valuable data on the animal[6].
Currently, we have a growing awareness of the important role that seals play in maintaining the balance of the Baltic ecosystem. It is worth noting that thanks to the efforts undertaken in the 1980s. i 90. international conservation efforts, the gray seal population in the Baltic Sea is steadily increasing. For the past 10 years, we have seen the gradual return of gray seals to the Polish coast[7]. And let’s not forget about the need to take measures to reduce anthropogenic pressures related to the inflow of pollutants into the waters, which may not cause damage “here and now,” while in the long term they are likely to disrupt the functioning and affect the preservation of this valuable species.
In the article, I used, among others. From the works:
[1] https://www.gov.uk/government/news/angler-rescued-from-cliff-face-and-aggressive-seals (accessed 14.02.23)
[2] https://www.iol.co.za/capeargus/news/clifton-baby-seal-attack-was-highly-unusual-but-not-unheard-of-say-marine-experts-ef65b3b0-c01f-4166-85e3-633dfb3e83d5 (accessed 14.02.23)
[3] https://www.dailymaverick.co.za/article/2023-01-05-why-are-we-seeing-an-increase-in-aggressive-behaviour-by-seals/ (accessed 14.02.23)
[4] https://www.wwf.pl/ssaki-baltyckie (accessed 15.02.23)
[5] https://chronmorze.eu/ (accessed 15.02.23)
https://fokarium.ug.edu.pl/foki/zagrozenia/ (accessed 15.02.23)
[6] https://fokarium.ug.edu.pl/pomoz-fokom/kiedy-spotkasz-foke/ (accessed 15.02.23)
[7] https://www.wwf.pl/zagrozone-gatunki/foka-szara (accessed 15.02.23)
