Freshwater Wildlife

Sea Lamprey Welfare and Control Methods in the Great Lakes

Sea lampreys are invasive in the North American Great Lakes, parasitising native fish. Their control via lampricide (TFM) raises welfare questions, while native sea lamprey populations in Europe face conservation threats.

Key Facts

Sea lampreys are native to the North Atlantic but invaded the Great Lakes via the Welland Canal
They parasitise lake trout and other salmonids, causing major fishery damage in the Great Lakes
TFM lampricide is applied to streams to kill larval lampreys before they metamorphose
In their native European range, sea lampreys are a species of conservation concern
Control programs kill millions of larval lampreys annually in Great Lakes tributaries

Welfare Considerations

TFM lampricide kills larval lampreys through respiratory disruption. Whether larvae at this life stage experience suffering comparable to adult vertebrates is uncertain, but precautionary welfare consideration is appropriate. The invasive Great Lakes context creates a genuine welfare conflict: lampricide use reduces harm to fish hosts but causes mortality to lampreys. Native European lamprey populations face different welfare threats from river barriers and habitat loss.

What You Can Do

Support research into more targeted and welfare-considerate lamprey control methods
Advocate for barrier technology that separates invasive from native lamprey management
Support river lamprey monitoring in European native range countries
Engage with Great Lakes Fishery Commission transparency in control program design
Donate to research distinguishing pain-capable larval lamprey nervous system function