Welcome to Habfish

Blooms of single-celled harmful algae are a recurring phenomenon in Danish waters with huge impacts on wild fish stocks as well as caged fish. These algae pose a serious risk and challenge because they can eradicate the entire fish population in the area affected in just a few days. This has detrimental consequences for the implicated fish farmers, in addition to recreational and commercial fishing. In Denmark fish farming has the potential to become an economically important industry, but for this to happen we need modern means to cope with harmful algal blooms (HABs).


It is assumed that fish are killed by either toxins (ichthyotoxins) leaked directly into the water column or through toxic algae clogging the fish gills. Yet, our exact knowledge about how fish are affected, the responsible toxins and how to quantify them is only at an early stage of exploration. Also, conventional techniques used by consultancies to identify and quantify these algae have often resulted in improper warnings, simply because species have been misidentified and implicated toxins cannot be quantified.

This project strives to identify the responsible ichthyotoxins and to develop new chemical methods for their quantification. Additionally it will design molecular probes for the most common species enabling exact species identification and enumeration using real-time quantitative PCR (qPCR). The physiological and pathological effects of the toxic algae and their toxins on fish will be determined. Finally, the project will explore the mechanisms behind possible acclimation of fish to ichthyotoxic algae and potential accumulation of toxins in fish.

The project will result in a significantly improved and state-of-the-art monitoring programme of ichthyotoxic algae and their toxins and enable a much better risk assessment during algal blooms in Danish waters.