GPS Technology Helps Solve Mysterious Death of Scotland Seals

Harbor Seals on the shores of Scotland has rapidly declined by 65 percent between 2001 and 2010. With the reduction currently at 90 percent, recent studies show that a toxin produced by algae is behind this strange mortality rate, all thanks to GPS technology.

The Harbour Seal Decline Project led by the Sea Mammal Research Unit (SMRU) and researchers from the University of St. Andrews, partnered with mobile carrier Vodafone to track the animals using telemetry tags. Telemetry tags help scientists discover what animals are doing and where they are going and monitor their environment round-a-clock.

After the thorough analysis of the information transmitted by the telemetry tags, initial results from the project show that a toxin produced by algae is the potential perpetrator. As part of the data collection, seal scat samples and seal carcasses undergo an examination to determine the seal's diet and exposure to toxins. Since carcasses found ashore on the Scottish coast are too decomposed, they resorted to examining the waters in the area.

In a report by the Daily Mail, water samples collected at feeding sites show traces of domoic acids which reproduce rapidly during blooms. This compound acts like a neurotoxin at high concentrations and, when eaten, could poison the animal's brain and can lead to its demise.

SMRU marine biologist Bernie McConnell told MailOnline that "it is possible that the decline may be due to DA but the puzzle is that we haven't been able to establish if these animals are eating enough contaminated fish to ingest a lethal dose of toxin." McConnell has been leading the project of tracking the animals since its decline in the year 2000.

Researchers hope to gather more results by next year. The initial results will be used to track down the feeding grounds of the seals and determine the cause of death of these animals and if anything could be done to stop the mortality.

"However, we are working hard to see if we can accurately estimate their exposure levels by measuring the levels of toxins in the fish in the areas where they are feeding, finding out what level of toxin remains in the live seals and what the health effects are of non-lethal doses of DA," McConnell added.

Harbor seals are among animals facing everyday threats such as pollution, climate change, oil spills, fish entanglement, and marine turbines, among others. Their habitat in Shetland, Orkney along the west coast of Scotland has recently been frequented by killer whales, thus increasing the risk of predation.