Research efforts at Partners Point are centering on the Redear Sunfish when it comes to quagga mussel infestation.
Last week, two separate but similar research projects were launched. One led by U.S. Bureau of Reclamation fish biologist Cathy Karp.
“We’re very concerned about the quagga mussels’ infestation,” she said.
The Redear Sunfish has caught the attention of researchers as a possible way of managing quagga mussel infestations when it comes to dams, docks and other pumping operations because the quagga mussels attach themselves to those surfaces.
“They are one of the few fish that eat quagga mussels,” Karp said.
Karp described the Redear sunfish’s way of digesting the quagga mussels’ shells as having teeth-like lining in its throat.
The Redear, although not native, was introduced into Lake Havasu as a sport fish many decades ago, Karp said.
According to Arizona Game and Fish Department’s website www.azgfd.gov, the Redear is native to the Savannah River in South Carolina; the Nueces River in Texas; the northern Mississippi River basin; and bodies of water in southern Indiana and Illinois.
The species was introduced to Arizona in 1946.
In the two separate studies, the Redear are confined in cages over a specific and designated time. The cages are placed offshore at Partners Point and monitored monthly with photography. Later, the photos are compared.
In Karp’s case, the study spans five months, or until May. Karp’s subjects will be extracted from the Lake by April. Last year, the study subjects were left until May, which was a little too long.
“The fish and the mussels started dying,” she said.
The cages, which are about 8 square feet, are equipped with solar shades.
Karp’s cages include suspended bricks hosting separate plates showing different stages of quagga infestation. A blank, or quagga-free, plate also is included. Two Redear are confined in the cages, with one cage sunk without any Redear.
Another study, similar but on a smaller scale is led by research scientist Carrie Culver, of University of California, Santa Barbara. Andy Brooks, project scientist, of Marine Science Institution at UC, Santa Barbara, has teamed up with her for the study.
Karps’s study is in its second year, Culver’s is in its first.
Like Karp’s, Culver’s study includes surfaces that are infested and those without.
“It’s to see if the caged fish will consume the mussels,” Culver said.
In theory, the studies could determine if the caged Redear could be placed around dams, docks and other operations.
“We’re not adding fish, but moving fish around,” she said.
The study’s funding is linked to an integrated pest management, or IPM, grant.
Culver said most grants of that type are geared toward agriculture pests. However, since quagga mussel infestations largely can impact piping, canals and other means of water transport used to sustain agriculture, the grant was secured for the quagga.
Culver’s study includes a dozen cages, also constructed of PVC pipe and mesh. Like Culver’s, the cages are sunk offshore at Partner’s Point until sometime in April.
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