Editorial: Current challenges in providing early warning of harmful algal and microbiological risk to aquaculture

The aquaculture sector is a major industry in Europe’s Atlantic Arc. Its continued sustainable growth is required to meet the increasing demand for farmed fish and shellfish. However, such expansion faces several microbiological challenges, with harmful algal blooms (HABs) being prominent among these.

A few species of naturally occurring marine microalgae can produce biotoxins. When conditions are favourable, these organisms can rapidly increase in abundance generating a HAB event. Farmed shellfish feed on these microalgae and can concentrate the biotoxins within their flesh. While the shellfish themselves are not harmed, their consumption poses a risk to human consumers. The impact of shellfish poisoning can range from mild gastrointestinal symptoms to neurological issues and, in extreme cases, may even lead to death.

Blooms of other harmful phytoplankton species have a damaging effect on farmed fish through deoxygenation, toxicity, or damage to the gills. In most cases, consumption of these fish would not be harmful to humans, but the associated production losses can be economically significant for the industry.

HAB and pathogen events are spatially and temporally variable. The aquaculture industry, therefore, relies on early warning indicators of these events to allow for the best possible mitigation measures to be put in place.