An Endangered Higgins' Eye Pearlymussel found in the Waspsipinicon River.  This is the first specimen found and documented in these waters in 80 years. - USFWS photo

Region 3 U.S. Fish and Wildlife Service divers, working with Iowa Department of Natural Resource biologists, located the first live Higgins' Eye Pearlymussel (Lampsilis higginsii) in interior waters of the state in more than 80 years.  The mussel was found as part of a survey of interior streams associated with recent recovery efforts for this species and was located in a reach of the Wapsipinicon River near Cedar Rapids, Iowa. 

During the week long field operation, FWS divers, Iowa DNR personnel, USFWS biologists, and U.S. Army Corp of Engineer staff searched miles of likely habitat on the Upper Wapsipinicon, Cedar, and Iowa rivers looking for evidence that recent reintroductions of this federally endangered species had been successful.  Over 2,350 mussels of 24 species were identified during the search including many state endangered and threatened individuals.  These rivers have, over the past several years, received tens of thousands of juvenile Higgins' Eye mussels as part of a range-wide recovery effort for the species.  The mussels were introduced to the Iowa rivers by releasing host fish, (usually walleye, smallmouth bass or largemouth bass fingerlings) that were carrying the mussels as larval encystments on their gills. 

Biologists from Genoa National Fish Hatchery, in cooperation with Iowa DNR officials, and the Mussel Recovery Team, (a consortium of state and federal cooperators tasked with recovery of this species),  have been carrying out these releases since 2001 on interior rivers in Iowa and in Wisconsin.  One of the many problems that biologists face with assessing the success of these types of reintroductions is locating released animals in these open riverine systems.  The juvenile mussels, which were artificially infested on known host fish at either the Genoa National Fish Hatchery, or in the field using a combination of wild captured and hatchery host stocks, can spend from days to months attached to their respective hosts until they reach the release stage and drop off the fish as a free living mussel.  Where these fish are located when this happens is a guessing game for field personnel who must then wait several years for the mussel to grow to a sufficient size to be detected, identified, and returned to the river. One State biologist made the analogy that, “It’s more that a needle in a haystack- it’s more akin to a needle in a hayfield!”  

Given these challenges it was rewarding for project personnel to find a three year old mussel within one river mile of the release site on the Wapsipinicon River that was identified in the field as a Higgins' Eye Pearlymussel. Subsequent DNA analysis of samples taken from the animal were confirmed by Dr. Bonnie Bowen of Iowa State University as indeed a Higgins-Eye Pearlymussel.  Further survey operations are planned for areas adjacent to this site to see if other individuals from these initial stockings can be located, meanwhile the project will continue to reintroduce this rare mussel to areas across the Midwest where it was once a component of the wild mussel community.