Several dozen years of hunting and environmental pollution resulted in the population gray seal In The seaBaltic dropped from 90 thousand to just 5 thousand pieces. The implemented protective measures allowed for partial reconstruction of the population and it currently numbers approximately 55,000. animals. However, partial hunting of representatives of this species is still allowed – their limits are set at 3,000 pieces per year.
Slow extinction
As the authors of the publication that appeared in “Journal of Animal Ecology”, due to the warming climate and a shortage of appropriately sized fish, the population of Baltic gray seals remains under threat. Using a mathematical model, these scientists showed that – when hunting at current levels is added to the mix – the species is at risk of slow extinction.
“It took us three generations to regenerate the gray seal,” he says Dr. Daire Carroll, lead author of the study. “Their population is currently growing, but our research shows that if the current hunting limit of 3,000 animals per year is reached, the survival of gray seals in the Baltic Sea will once again be at risk.”
Scenario research
Carroll and his colleagues created a mathematical model of gray seal population growth and examined several different future scenarios. They tested the effects of different hunting pressures, levels of food availability and the consequences of less sea ice.
“In all our models, killing 3,000 seals each year always led to population declines; even in the most optimistic scenarios in terms of climate and marine environment. Our conclusion is therefore: the current hunting limit set for the Baltic Sea is inappropriate. If the seal population is to continue to recover, the maximum number of animals that can be hunted is 1,900. However, if more serious environmental changes occur that will negatively impact this species, this number will need to be reduced even more,” Dr. Carroll notes.
The researchers also created a model showing how the seal population would have increased over the past 20 years if they had not been hunted at all. “This allowed us to estimate the long-term impact of current hunting limits on the population. We also simulated how further climate warming would affect seals,” says the author of the publication.
The scientist explains that Baltic gray seal pups have a better chance of survival if they are born on an ice floe rather than on the mainland. On the ice, mothers and young are less threatened by predators, people and infections that spread very easily in dense land colonies. Climate warming and the decreasing ice surface may have a very negative impact on the condition of this species. When hunting is added to this, even at its current rate, the Baltic gray seal population is at risk of complete collapse.
The threat of extinction has already occurred
In the second half of the 20th century, gray seals were critically endangered. In addition to environmental pollution, widespread hunting was to blame for this situation. Seals were considered pests that harmed fisheries; they were also obtained for valuable skins.
The Baltic Sea countries agreed that conservation measures should be taken to prevent the total loss of the gray seal. Introduced, among others: hunting limits and monitoring of the number of individuals began.
The fishing industry took a stand
However, as the population recovered, it came into conflict with fishing industry. Therefore, in 2020, the possibility of licensed hunting for these animals was introduced Finland and Sweden. In total, just over 3,000 may be issued annually. such permits.
– The shooting of individual seals, which destroy fishermen's tools, has always been allowed and to such a small extent it did not pose a threat to the population – he explains prof. Karin Hårding, ecologist and co-author of the study. – But we are talking about a maximum of several hundred individuals per year; the shootings did not affect entire groups of seals either.
“Meanwhile, the new law allowing licensed hunting is another matter; “it threatens the survival of the species” – sums up the expert. (PAP)
Katarzyna Czechowicz
