New project on fish-killing algae and their toxins funded by The Research Council of Norway

February 8, 2021 Off By Ingunn Samdal
The consequences of the bloom of Chrysochromulina leadbeateri in 2019 were disastrous for the aquaculture industry in Northern Norway. The boxes contain dead salmon transported to land in Sør-Troms. Photo: Northern Lights Salmon.

Algal blooms are seasonal phenomena in marine and freshwater ecosystems. Their frequency and severity are increasing, at least in part because of human impact. Algal blooms may be harmful (so-called HABs) and result in the die-off of vertebrate and invertebrate species. The reason for such mortality events can be variable and complex, and may include oxygen depletion or specific toxic substances that are produced by the algae. The ToxANoWa project is inspired by the recent HAB event that occurred in Northern Norway during the spring 2019. The event, which was disastrous for the aquaculture industry, resulting in total lost production of about 40,000 tons of salmon, equating to financial losses estimated at around NOK 2.2 billion (USD 225 million). The responsible species for the toxicity of the bloom has been identified as Chrysochromulina leadbeateri, and collaborators are in possession of both field samples and laboratory cultures of this algal species. At present, very little is known about why this species may be toxic to fish or whether there are environmental conditions that are necessary to induce toxicity. ToxANoWa aims to shed light on this by bringing together researchers with backgrounds in marine biology, toxin chemistry and toxicology.

The project also aims to study species in the related genus Prymnesium, which were historically responsible for HABs in Scandinavian waters. One of the species, P. parvum, is known to produce chemicals that are highly toxic to fish — these are known as prymnesins. P. parvum grows in many regions worldwide, but the chemistry and toxicology of the prymnesins is still not well understood. This is in large part because prymnesins are not readily available, and ToxANoWa thus aims to produce selected prymnesins so they are available for research and monitoring purposes. In addition, the ToxANoWa team will make efforts to raise prymnesin antibodies that may be used to develop research and monitoring tools to simplify selective extraction and detection of these toxic chemicals.

Another Prymnesium species is P. polylepis, which was responsible for a large and toxic bloom in the Kattegat and Skagerrak in 1988. It is still unknown why this species is harmful to fish, but application of the modern technologies in ToxANoWa will hopefully provide additional clues.

This project is a collaboration between the Norwegian Veterinary Institute, University of Oslo, the Technical University of Denmark and the National Research Council of Canada, and will start in June 2021.