Fewer fish and more otaries could be behind the growing number of fur seals dying as a result of collisions or drowning in fishing nets. The South Atlantic Institute for Environmental Research has published the initial results of its scientific investigation in the hope of improving fisheries management.
In Falkland, what fur seals and fishermen have in common is squid. The initial results of a scientific study by the South Atlantic Institute for Environmental Research, published in Global Ecology and Conservation on 29 August, show that fur seals and fishing vessels share common hunting grounds in the south-west of the archipelago.
However, Falkland fur seals are sometimes victims of fishing. They are trapped in nets or killed by the propellers of trawlers manoeuvring in the waters of the Patagonian continental shelf. These sightings have been increasing for several years. The first step to understanding the situation is to define the habitats and fishing grounds of these animals.
Working with the British Antarctic Survey, British universities and the government of the Falkland Islands, the researchers placed sensors and GPS on 18 females from a fur seals colony on Bird Island.
Biologists estimate that there are 400,000 fur seals along the coast of the southern half of South America. The Falkland Islands are home to around 50% of them. No doubt attracted by one of the most productive maritime areas on the planet.
There, powerful currents remobilise nutrients around the Falklands, attracting trawlers and longliners. Fishing accounts for 60% of the archipelago’s gross domestic product. According to the Falkland Islands Government, 50% of the squid consumed in Europe comes from these waters.
Last year’s government report on fishing mentions the sighting of 53 fur seals killed. This observation was conducted on 99% of Calamari fishery and less than 4% of the finfish effort. Of these fur seals, 14% were hit by the propeller and 70% drowned. Twenty-four of them were caught in nets equipped with escape devices, during three weeks of bad weather around Beauchêne Island. The trap may have malfunctioned because of the heavy swell.
One possible explanation for the increase in mortality is the growth in fur seal populations, but other factors may also be at play. Southern blue whiting stocks collapsed in 2004 and 2005. Then in 2015, rock cod collapsed too. Fishermen switched to hake. Perhaps these changes have led fur seals to prey more on squid, the researchers supposed.
This study lays the foundations for improving fisheries management, which involves not just the Falklands but other countries, because interactions take place in the international waters of other maritime areas.
More needs to be known before protective areas or fishing seasons can one day be defined. The study is based on individuals from single colony, observed for one to four weeks, active in the south-west. It remains to be seen where the other fur seals hunt around the archipelago.
Camille Lin, PolarJournal
Link to study and report :
- Riaz, J., Orben, R.A., Jones, K.A., Shapiro, M., Winter, A., Brickle, P., Baylis, A.M.M., 2023. Spatial overlap between South American fur seal foraging effort and commercial trawl fisheries in the Falkland Islands. Global Ecology and Conservation 46, e02615. https://doi.org/10.1016/j.gecco.2023.e02615
- Falkland Islands Government, (2023). Fisheries Department Fisheries Statistics, Volume 27, 2022: 94pp Stanley, FIG Fisheries Department
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