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Recent studies have shown the potential of acoustic deterrents against invasive silver carp (Hypophthalmichthys molitrix). This study examined the phonotaxic response of the bighead carp (H. nobilis) to pure tones (500– 2000 Hz) and playbacks of broadband sound from an underwater recording of a 100 hp outboard motor (0.06–10 kHz) in an outdoor concrete pond (10 × 5 × 1.2 m) at the U.S. Geological Survey Upper Midwest Environmental Science Center in La Crosse, WI. The number of consecutive times the fish reacted to sound from alter- nating locations at each end of the pond was assessed. Bighead carp were relatively indifferent to the pure tones with median consecutive responses ranging from 0 to 2 reactions away...
Dams create barriers to fish migration and dispersal in drainage basins, and the removal of dams is often viewed as a means of increasing habitat availability and restoring migratory routes of several fish species. However, these barriers can also isolate and protect native taxa from aggressive downstream invaders.We examined fish community composition two years prior to and two years after the removal of a pair of low-head dams from Boulder Creek,Wisconsin, U.S.A. in 2003 to determine if removal of these potential barriers affected the resident population of native brook trout (Salvelinus fontinalis). Despite the presence of other taxa in the downstream reaches, and in other similar streams adjacent to the Boulder...
The effectiveness of an acoustic barrier to deter the movement of silver carp, Hypophthalmichthys molitrix, and bighead carp, H. noblis, was evaluated. A pond (10 m, x 5 m x 1.2 m) was divided in half by a concrete-block barrier with a channel (1 m across) allowing fish access to each side. Underwater speakers were placed on each side of the barrier opening and an outboard motor noise (broadband sound; 0.06 – 10 kHz) was broadcast to repel carp that approached within 1 m of the channel. Broadband sound was effective at reducing the number of successful crossings in schools of silver carp, bighead carp and a combined school. Repulsion rates were 82.5% (silver carp), 93.7% (bighead carp) and 90.5% (combined). This...