streams and rivers where no other gear can be effectively deployed. The trawl has helped scientists better understand what kinds of organisms live in such places and where they are distributed. Below and on the following page are some examples of rare and unusual organisms captured by the trawl in Missouri. The Missouri Trawl is an effective sampling gear in deep, swift rivers. It was designed to skim the bottom of streams and rivers where no other gear can be effectively deployed. The trawl has helped scientists better understand what kinds of organisms live in such places and where they are distributed. Invitations for workshops soon followed from neighboring state researchers.
During the early 2000s, trawling workshops were conducted in Tennessee, Nebraska, Illinois, Kentucky, Arkansas, Iowa, and Mississippi in conjunction with ongoing large river monitoring and research efforts in those states. Each workshop yielded new fish records and further increased biologists’ interest in using the technique. However, it wasn’t until invitations began coming from Minnesota, New York, Pennsylvania, Vermont, and Canada that field station staff began to understand the relevance of the research to a much larger resource contingency—perhaps worldwide in scope. Researchers from the Netherlands, Poland, Australia, and South America have all expressed an interest in using or have already used Missouri Trawls in their programs. A demonstration in China was completed in 2009 as part of large-river scientific exchange program and the Mini-Missouri Trawl was used on the Yangtze River.
The Missouri Trawls are used to capture young individuals of many fish species because understanding early life information (reproduction) is important to the management of fish. If the species doesn’t reproduce there will soon be no fish for anglers to catch. The trawls are being used to study early life information for paddlefish, channel catfish, blue catfish, shovelnose sturgeon and many other species. They are also used to investigate young crappie abundance in some lakes because other methods do not capture them.
Trawling is useful for capturing species that are rarely sampled by other gear. Missouri Trawls have captured more Pseudiron mayflies than any other sampling gear used. The Pseudiron mayfly is known to be eaten by the federally endangered pallid sturgeon. They have also been used to capture Ohio shrimp (a Missouri species of conservation concern), and new research is uncovering their usefulness for sampling young mussel populations in large rivers.
Trawling is a useful method for