Great Lakes Fish Tag and Recovery Laboratory
2015 Mass Marking Program Field Collections Underway
BY KEVIN PANKOW, GREEN BAY FWCO
The Great Lakes Fish Tag and Recovery Laboratory, headquartered at the Green Bay Fish and Wildlife Conservation Office (FWCO), began its fourth season assisting state agencies around Lakes Michigan and Huron in recovering coded-wire tags (CWT) and collecting biological data on sport-caught salmon and trout. The data and tag recovery efforts are part of the Great Lakes Mass Marking program, a multi-agency collaboration designed to determine levels natural reproduction, movement patterns, and the relative contributions of salmon and trout stocked at different locations to the fishery.
Through this program, the Great Lakes Fish Tag and Recovery Lab operates four automated tagging trailers at state and federal hatcheries to ensure all Chinook salmon and lake trout stocked into Lakes Michigan and Huron receive an adipose fin clip and a CWT injected into the snout. Each CWT is a 1.1 mm long piece of stainless steel wire with a laser etched numerical code specific to a group of fish (i.e., specific hatchery origin, strain, year class, and stocking location). The missing adipose fin identifies fish of hatchery origin and signifies fish that contain a CWT.
Each year, the Great Lakes Fish Tag and Recovery Lab hires 11 bio-technicians to assist state partners in recovering CWTs and collecting biological data on fish landed from April to October at boat landings, cleaning stations, fishing tournaments and weirs. In 2014 alone, Service bio-technicians collected data on nearly 22,000 fish, including about 12,450 Chinook salmon and 4,400 lake trout. The Lab coordinates data collection efforts and advises biological technicians assisting Departments of Natural Resources in Indiana (Michigan City), Wisconsin (Sturgeon Bay and Milwaukee), Illinois (Zion) and Michigan (Charlevoix and Alpena).
The 2015 field season began in Michigan City, Indiana on April 17 and 18 when Fish Biologist/Data Analyst Matthew Kornis and Fish Biologist Kevin Pankow trained two bio-technicians on proper protocol for Mass Marking Program field collections. The biological technicians received hands-on instruction in identifying different salmon and trout species, collecting basic biological data (e.g., fish length, weight, sex and maturity), collecting aging structures (i.e., otoliths and scales), determining the presence or absence of CWTs and various fin clips, and identifying different types of sea lamprey wounds. Throughout the summer and fall, snouts containing CWTs will be collected and sent to the Great Lakes Fish Tag and Recovery Lab, where CWTs are extracted and read. The information contained in the CWTs are then coupled with the biological data collected by the bio-technicians and stored in a database for analysis.
In addition to the core objectives being collected this season, the Mass Marking Program will use its lake-wide sampling network to collaborate on two additional studies focused on tissues collected from Lake Michigan salmonines (Chinook salmon, Lake trout, Steelhead, Brown trout and Coho salmon). The Great Lakes Fish Tag and Recovery Lab has partnered with scientists at the University of Notre Dame to collect and analyze dorsal muscle tissue to better understand how trophic structure mediates bioaccumulation of mercury. In addition, a partnership with the Illinois Natural History Survey will use collections of dorsal muscle tissue, belly flaps and stomachs for use in stable isotope and fatty acid analyses aimed at describing diet and niche overlap of Great Lakes predatory fish.