Human impact has a greater impact on Baltic fish stocks than seals, according to a study.
A study has confirmed that seals feeding on cod, herring and sprat in the Baltic Sea would not adversely affect the fish population, as much as man-made causes like climate change, nutrient load and fisheries would.
Conducted by Stockholm University, the research focused on fish living in open waters, and involved computer simulations that went all the way to the year 2098.
The findings showed that the scenarios with the highest temperature and nutrient load are more damaging to cod, but not herring and sprat.
According to the press release, such a scenario would lead to “worsened effect of hypoxia and as a result less fish. Higher nutrient load together with higher temperatures could also lead to higher toxic cyanobacterial blooms of low food quality—making fish smaller and slender.”
We currently have 30,000 grey seals in the Baltic Proper, but we can even have more than 100,000 seals and it will still not affect the amount of cod negatively as much as climate change, nutrient load and fisheries,” says David Costalago, a former postdoctoral researcher at Department of Ecology, Environment and Plant Sciences, Stockholm University
“We need to find ways to both secure the revenues of the fishers and guarantee the conservation of the fish stock and good status of the grey seal population,” says Monika Winder, professor at Department of Ecology, Environment and Plant Sciences, Stockholm University.
On the findings, she adds, “We want our insights to affect management and conservation that considers the whole ecosystem and multiple pressures, not only the direct biological interaction between fisheries and seal. Often debates about the impact of seals arise from poor understanding of the complexity of predator-prey interactions.”