BY PAUL G. LARSON, IRON RIVER NFH
All fish hatcheries need to know the number of fish that they are holding in a raceway or tank. This number is important for a number of reasons such as the amount of feed required and whether there is adequate space available for the fish in the tank or raceway. Typically, the inventory process involves finding the number of fish per pound. This consists of taking samples of fish (usually about 200 per sample) and recording the weight followed by counting the number of fish in the samples. Once this number is derived, fish can be inventoried by weight for the raceway or tank. At Iron River National Fish Hatchery (NFH) where 1.4 million fish are raised annually, this is time consuming. Hatchery staff is always interested in adopting methods that may expedite the processes and allow for day to day activities, like sample counting and inventories, to be carried out more efficiently and accurately.
Iron River NFH purchased a Vaki Micro Counter in the fall of 2014. Fish move through a scanning area in the machine where outlines are recorded. Special software is used to analyze and count each image. It has the ability to accurately count fish at the rate of 36,000 to 570,000 fish/hour depending on the fish size. What once took days to accomplish can now occur in mere hours.
So far the hatchery has had the opportunity to test the accuracy of the machine with pre-inventoried fall fingerling lake trout and conduct monthly sample counts. Future testing is anticipated with smaller fish during late winter and early spring 2015. The results for comparing accuracy and time savings have been positive and at this point it looks like the counter will be an effective tool for the hatchery.
BY MARY WILSON, MARQUETTE BIOLOGICAL STATION
During the 2014 field season, the U.S. Fish and Wildlife Service (Service) staff made substantial contributions to guiding the efforts of the Sea Lamprey Control Program (SLCP). SLCP staff stationed at the Marquette and Ludington biological stations worked tirelessly to reduce the devastating effects of the invasive sea lamprey on the Great Lakes fishery.
The larval assessment teams are responsible for finding streams and tributaries harboring sea lamprey larvae around the Great Lakes. They use specialized electrofishers to irritate the larvae to the point that they leave their burrows in the stream bottom where they are captured and identified. The data collected is used to estimate the sea lamprey larval population in each infested stream. The teams survey 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 how the larval population is distributed within a stream.
The crews’ work spread across eight Great Lakes states and access to many locations required remote travel by hiking, ATVs and boats.A total of 428 streams and waterways were surveyed and included assessments at 3,082 different sites. All of this work took place during the field season that lasts from April to October. When larval survey sites border the United States and Canada, the Service often partners with the Department of Oceans and Fisheries Canada staff to complete these surveys. Larval assessments are critical to successful sea lamprey control.
BY MARY WILSON, MARQUETTE BIOLOGICAL STATION
The accomplishments U.S. Fish and Wildlife Service’s Sea Lamprey Control Program during 2014 were exceptional and noteworthy. The many large river systems that were targeted for treatment as part of a large-scale treatment initiative in addition to the base program level of lampricide control proved ambitious and its accomplishment was no small feat. The staff from the Marquette and Ludington biological stations combined forces with the Great Lakes fishery Commission and their international partners from Fisheries and Oceans Canada to deliver an outstanding program of lampricide control, working around the clock and in challenging environments to reduce the impacts of the invasive sea lamprey on the Great Lakes fishery.
The lampricide control teams apply chemicals to streams that have been found to harbor larval sea lampreys. Teams often worked 10 days straight to complete a comprehensive treatment on just one stream. Lampricides are typically applied for 12 hours straight and staggered shifts are needed that require staff to report at unconventional times such as 4 a.m. or 11 p.m. During the first few days of a treatment, employees travel to a stream site and begin tests to determine how much TFM (the chemical used to remove larval sea lampreys from streams) will be needed. Crews also conduct studies with a dye to measure stream flow characteristics and plan application and boost sites needed to carry the treatment the necessary distances for effective removal. The teams regularly coordinate with local landowners to get access to private or remote areas of stream. The lampricide team targets many sites across eight states throughout the Great Lakes region. Highlights regarding the U.S. lampricide control operations during 2014 include:
• Completion of lampricide treatments in 50 streams and 7 lentic areas.
• Removal of over 18 million larvae from Great Lakes tributaries.
• Coordination with 537 landowners to deliver effective treatments .