Implementation and testing of hatchery enhancements at Allegheny National Fish Hatchery to increase production and improve health and quality of juvenile bloater raised for restoration stocking in Lake Ontario

Larry Miller (USFWS, larry_m_miller@fws.gov), David Blick (USFWS), Doris Mason (USFWS), Terry Richards (USFWS), John Coll (USFWS)

The proposed project will install 16 15-foot circular fiberglass tanks to replace 10 45-year-old concrete raceways (scalable down to 8 tank option). The project will also assess a side-by-side production level comparison of fish health, water use, fish growth, hatchery operational costs and, hatchery production by comparing the current serial water use concrete raceways vs Cornel-style circular fiberglass tanks operated in single water pass through mode. An existing raceway series will be modified for the installation of 16 Cornel-style circular fiberglass tanks operated in singular water pass through mode. An adjacent concrete raceway series in the same raceway building will be operated as it has been historically for bloater. These will constitute the two main treatments for this study. Although the proposed tank design is constructed as a single water pass system, the design can accommodate future addition of a recirculation system to reduce water use. Coregonines are schooling native prey species in the Great Lakes that are constantly swimming. These fish are best reared in these large smooth wall circular tanks. In rectangular raceways they swim in an oval pattern and often contact the straight walls which is believed to cause damage to the snout and head that can later lead to malformation of the mouth as they grow. Deformed mouth parts have been observed in some of the older fish held for long periods in captivity for at least some of life in rectangular raceways. In addition, concrete raceways require frequent cleaning and physical brushing of the bottom of the raceways to remove fish waste and excess feed that settles out of the water column. The bushing action disturbs coregonine species, breaking up schooling and startling the fish causing them to collide with side walls and end screens. Circular tanks are self-cleaning due to the swirling action that concentrates settled solids in the center of the tank where they are continuously removed via partial flow through the center floor drain and thus require only infrequent brushing, reducing disturbance to the fish. Further, fiberglass tanks can be thoroughly cleaned and disinfected thus reducing the chance of transferring disease between one rearing cohort and the next.