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Harmful phytoplankton

Shellfish poisoning of humans by marine phytoplankton derived toxins that have been vectored by commercially harvested shellfish are a concern for the shellfish industry and regulatory bodies that oversee the protection of human health.

A variety of stakeholders including the shellfish industry, regulatory authorities, monitoring organisations, environmental scientists and medical scientists are involved in the production of shellfish and the regulation, monitoring and prevention of shellfish poisoning events. However, opportunities for bring this wider community together for discussion of the "issues" relating to shellfish poisoning are rare.

To begin to address this problem a workshop funded by the joint research council Environment & Human Health Programme*, was held at the Scottish Association for Marine Science, Dunstaffnage Marine Laboratory, Oban, during October 2007.

The full report and its detailed conclusions and recommendations can be downloaded here.

Report of the NERC UK HAB Workshop, Oban, October 2007

Harmful plankton

The workshop sought to bring together scientific experts, regulators and representatives of the shellfish aquaculture industry to establish the current level of understanding of shellfish poisoning in the UK in terms of the causative organisms, their toxicity and the effects on humans of the consumption of the toxins.

In particular, the participants sought to generate:

  • An improved understanding of the factors that govern harmful algal blooms (HABs), shellfish poisoning and human heath in UK waters.
  • Better integration of research effort across the sector, with the aim to guide future activity.
  • Provision of improved advice to regulatory bodies such as the Food Safety authorities/agencies to allow for better protection of human health.

The workshop attracted 47 participants from a range of disciplines. In addition to delegates from Scotland, England, N. Ireland and the Isle of Man, participants from the Republic of Ireland, USA, Norway and New Zealand also attended.

This is thought to be the first workshop of its kind in the UK, bringing together environmental scientists, medical scientists, monitoring organisations, regulators, industry bodies and practitioners in a single forum for meaningful discussions.

Conclusions of the workshop:

  • The products of seafood aquaculture are increasingly important as a foodstuff on a global basis. The weight of current scientific evidence is that, with the current levels of monitoring and end product testing, UK shellfish can continue to be regarded as a safe and healthy premium product.
  • While monitoring provides an effective safeguard to human health in the UK, the general public often still perceive seafood as "risky". Further basic research on the environmental conditions that lead to harmful phytoplankton blooms and shellfish toxicity to humans is therefore required, this having the capacity to demonstrate the safety of seafood as well as better quantifying the dangers that do exist.
  • Applied research to develop, in particular, toxin standards, rapid toxin tests and risk assessments for harmful blooms and their toxicity level is required. Investment in developing technologies such as molecular taxonomy is to be encouraged.
  • Protocols to definitively assess the real risk, both acute and chronic, to humans of "new" and existing shellfish such toxins are required. This is related to a lack of biomarkers for effects of harmful algal toxins.


*The Joint Environment and Human Health Programme, is funded by NERC, DEFRA, the EA, the MOD and the MRC.

Keith Davidson (Scottish Association for Marine Science, Oban)
Eileen Bresnan (Marine Scotland Science Marine Laboratory, Aberdeen)