Determining the underwater hearing abilities and the efficacy of sensory deterrents on seaducks
Dates
Start Date
2015-10-01
End Date
2018-10-01
Summary
Bycatch is the incidental mortality or injury in fisheries operations. Many seabirds are proficient swimmers, some diving many tens of meters in pursuit of fish (Brierley and Fernandes 2001, Regular et al. 2013). Diving seabirds swim into, become entangled and drown in fine nylon mesh gill nets due to their lack of visibility. This problem is often exacerbated at dawn and dusk when birds are most actively feeding and when nets are hardest to see (Melvin et al. 1999). The North American Waterbird Conservation Plan identifies fisheries bycatch as a serious threat to at least 17 species of seabirds in the Mid-Atlantic/New England/Maritimes, and Southeastern regions, an area including all U.S. Atlantic waters (Kushlan et al. 2002). To [...]
Summary
Bycatch is the incidental mortality or injury in fisheries operations. Many seabirds are proficient swimmers, some diving many tens of meters in pursuit of fish (Brierley and Fernandes 2001, Regular et al. 2013). Diving seabirds swim into, become entangled and drown in fine nylon mesh gill nets due to their lack of visibility. This problem is often exacerbated at dawn and dusk when birds are most actively feeding and when nets are hardest to see (Melvin et al. 1999). The North American Waterbird Conservation Plan identifies fisheries bycatch as a serious threat to at least 17 species of seabirds in the Mid-Atlantic/New England/Maritimes, and Southeastern regions, an area including all U.S. Atlantic waters (Kushlan et al. 2002). To reduce the threat of bycatch a number of mitigation ideas are being investigated, including visual and acoustic methods.
There is evidence that pingers, one possible acoustic mitigation method, work for at least some marine mammals, such as the harbor porpoise (Phocoena phocoena), but pinger effectiveness is a more open question for seabirds. Previous studies (for example, Melvin et al. 1999) have been inconclusive, showing potential deterrence for one bird species (e.g., Common Murre, Uria aalge) but not for others (e.g., Rhinoceros Auklet, Cerorhinca monocerata). An important first step in addressing this issue is to obtain a sensory baseline and investigate what bycatch-susceptible birds can actually hear underwater (Wiedenfeld et al. 2015).
Underwater hearing abilities have been examined in species of dolphins, whales, seals, sea lions, fishes, turtles, frogs, and even some invertebrates (Terhune & Ronald, 1975; Thomas et al., 1988; Christensen-Dalsgaard et al, 1990; Römer & Tautz, 1991; Budelmann, 1992; Kastak, 1996; Christensen-Dalsgaard et al., 2012; see Fay, 1988 for a compilation of results from many species). However, there are currently no measurements of underwater hearing by any diving bird. The goal of this project is to determine the underwater hearing capabilities of seaducks and then apply that knowledge to test visual and acoustical mitigation methods in hopes of providing some insight into the efficacy of these methods in reducing bycatch of seaducks.
Objectives:
Determine the underwater hearing capabilities of the long-tailed duck (Clangula hyemalis), surf scoter (Melanitta perspicillata), white-winged scoter (Melanitta fusca), lesser scaup (Aythya affinis) and harlequin duck (Histrionicus histrionicus) using psychoacoustic techniques.
Determine the efficacy of auditory and visual deterrents on these seaduck species to provide recommendations on which techniques to field test.
