Harmful algae and mariculture in New Zealand

Harmful algal blooms and their impacts on the Greenshell™ mussel industry in New Zealand over the last decade are reviewed. The response of the regulatory authorities, seafood industry, and scientists to the first significant toxic Gymnodinium blooms in the summer of 1992/1993 has resulted in a well-organized interest group including scientists, commercial interests, and public health regulators. Nearly all known toxic species occur in New Zealand and unique and internationally accredited microalgal monitoring programmes have been developed. New methods, such as DNA probes, have been integrated into the system for rapid identification of species that are difficult to differentiate morphologically. Monitoring is carried out weekly, with results being dispatched within 24 h of sample receipt to enable risk assessments of toxicity by shellfish harvesters. The introduction of this system has saved the shellfish industry money and has reduced the amount of contaminated product being harvested and then rejected. All the main marine biotoxins are monitored, including paralytic, neurotoxic, diarrhetic, and amnesic shellfish toxins, and also compounds such as yessotoxin, pectenotoxin, and gymnodimine. Blooms that could affect farmed finfish or wild marine biota are also reported. Harmful algal monitoring is constantly reviewed in the light of new research and incorporates local knowledge of oceanographic and climatic conditions.