WASTE-WATER DISCHARGES MAY BE MOST HAZARDOUS TO FISH DURING WINTER

Winter Stress Syndrome (WSS) is a condition of severe lipid depletion in fish brought on by external stressors in combination with normal re ductions in feeding and activity during cold weather. Fish can develop this syndrome in response to chemical stressors such as water polluta nts, or biological stressors such as parasites. Substantial mortality can result, potentially changing year-class strength and population st ructure of the affected species, and altering community-level 'ecologi cal interactions. Aquatic contaminants should be evaluated in the cont ext of seasonal metabolic changes that normally occur in test organism s. WSS could be an important, but as yet unquantified, cause of mortal ity in many circumstances. Wastewater discharges may pose a greater to xic threat to fish during winter than at other times of the year. A co mprehensive protocol for aquatic hazard assessment should include test ing for WSS. Published by Elsevier Science Ltd