Service employee Matt Symbal conducts a sea lamprey larval assessment survey in the Big Garlic River, Michigan. - Photo Credit: USFWS - Lynn Kanieski

Sea Lamprey Control staff from the Ludington and Marquette Biological Stations conduct a larval assessment survey on the St. Clair River, Michigan. - Photo Credit: USFWS - Lynn Kanieski

The 2015 Sea Lamprey Control Program field season has come to a close, and with that, the U.S. Fish and Wildlife Service would like to highlight and share some of the remarkable work accomplished over the past 7-8 months. During the field season, sea lamprey control staff based in the Ludington and Marquette Biological Stations work around the clock, and at times, 10 day shifts in order to reduce the impacts of the invasive sea lamprey on the Great Lakes ecosystem.

Service employees work in one of three units of sea lamprey control: larval assessment, lampricide control and adult assessment and barriers. Each unit plays a different role in facilitating the decline of sea lampreys in the Great Lakes, but collectively they work together to keep this voracious parasite at bay.

The larval assessment unit is responsible for finding streams and tributaries containing sea lamprey larvae throughout the Great Lakes. They use specialized electrofishers to stimulate larvae from their burrows and estimate the sea lamprey larval population in each infested stream. The team surveys all tributaries to the Great Lakes that have potential to harbor sea lampreys, including those where larval sea lampreys have been found in the past and those where they have never been detected. Larval assessment data are then used to decide which streams will be treated with lampricides the following year, the exact locations where lampricides will be applied in each stream and the spatial distribution of the larval population within a stream. Access to many locations requires travel to remote areas of a stream by hiking and ATVs.

By the numbers, here is just a brief glance at what the larval assessment team was up to during 2015:
• Number of sites sampled for larval sea lampreys: 2,842
• Number of streams surveyed for larval sea lampreys: 315
• Number of offshore areas surveyed for larval sea lampreys: 33
• Number of employees in the larval assessment program: 12 from Ludington Biological Station and 16 from Marquette Biological Station
• Number of states worked in: 8

As shown by the numbers, the larval assessment team assesses thousands of sites from northern Minnesota to the southern tip of Wisconsin, east to Buffalo, New York. All of this hard work happens during the short field season that lasts from April to October. When larval survey sites border the United States and Canada, the Service often partners with staff from the Department of Fisheries and Oceans, Canada to complete the surveys. The larval assessment unit is crucial to sea lamprey control because it determines  when and where to treat streams, if treatments have worked in the past and where they are most needed in the future.