Sea lampreys, known as “vampire fish,” have become a major concern in the Great Lakes as their population surges due to a disruption in control efforts during the COVID-19 pandemic. Sea lampreys are parasitic fish that attach themselves to host fish, sucking out their blood and vital body fluids. They have a circular row of teeth, a serrated tongue, and an eel-like shape that allows them to latch onto their hosts.
According to the National Oceanic and Atmospheric Administration (NOAA), sea lampreys are originally native to the northern and western Atlantic Ocean. However, they invaded the Great Lakes in the early 19th century through the Welland Canal, which connects Lake Ontario and Lake Erie. Within a decade, they spread to all five Great Lakes, preying on commercially important fish species such as trout, whitefish, perch, and sturgeon. The unchecked proliferation of sea lampreys led to the collapse of the trout fishery in the lakes.
In the 1960s, sea lampreys drastically reduced the annual commercial catch of lake trout in the upper Great Lakes from 15 million to half a million pounds. The impact of these invasive parasites was devastating for the fishing industry and the ecosystem of the lakes.
To manage the population of sea lampreys, the Great Lakes Fishery Commission, in collaboration with the US Fish and Wildlife Service and Fisheries and Oceans Canada, has implemented control measures. These efforts have been largely successful, resulting in a 90% reduction in sea lamprey populations in most areas of the Great Lakes.
However, the COVID-19 pandemic and subsequent travel restrictions interrupted the agencies’ ability to conduct necessary population management operations. As a result, the population of sea lampreys has seen an uptick across the Great Lakes. Fishery managers report an increase, though the exact magnitude is unclear.
A 2022 report from Undark Magazine revealed that in 2020, the crews responsible for sea lamprey population control could only treat about 25% of the target streams due to the limitations imposed by the pandemic. The following year, they were able to reach 75% of their targets. Treatment involves the carefully timed application of lampricides, which are pesticides designed to reduce the lamprey population. However, this method is labor-intensive and costly, with an estimated annual cost of $15 to $20 million.
The resurgence of sea lampreys underscores the importance of consistent and effective population management efforts. With the pandemic interrupting these operations, the lamprey population has been able to rebound. It will require renewed efforts and resources to bring the population back under control and protect the native fish species in the Great Lakes.
In conclusion, the Great Lakes are facing a resurgence of sea lampreys, an invasive species that preys on commercially important fish. The COVID-19 pandemic disrupted population management efforts, allowing the lamprey population to increase. Effective control measures are crucial to protect the ecosystem and fishing industry in the Great Lakes.