Marine ecologists use Sound Metrics DIDSON Sonar to document fish behavior. The published article: Use of High-Resolution DIDSON Sonar to Quantify Attributes of Predation at Ecologically Relevant Space and Time Scales can be seen under our Fisheries Resources section.
Article Highlight:
Use of High-Resolution DIDSON Sonar to Quantify Attributes of Predation at Ecologically Relevant Space and Time Scales
Marine Technology Society Journal
January/February 2013, Volume 47, Number 1
Authors:
Victoria E. Price
Department of Marine Sciences and National Undersea Research Technology and Education Center
University of Connecticut
Peter J. Auster
Department of Marine Sciences at the University of Connecticut and Sea Research Foundation
Mystic Aquarium, Groton, Connecticut
Laura Kracker
NOAA National Centers for Coastal Ocean Science
Charleston, South Carolina
Abstract
Predator-prey interactions of large vagile fishes are difficult to study in the ocean due to limitations in the space and time requirements for observations. Small-scale direct underwater observations by divers (ca. <10 m radius) and large-scale hydroacoustic surveys (10 s m2 to 100 s km2) are traditional approaches for surveying fish. However, large piscivorous predators identify and attack prey at the scale of meters to tens of meters. Dual-Frequency Identification Sonar (or DIDSON) is a high-resolution acoustic camera operating in the MHz range that provides detailed continuous video-like imaging of objects up to a range of 30 m. This technology can be used to observe predator-prey interactions at ecologically relevant space and time scales often missed by traditional methods. Here we establish an approach for quantifying predation-related behaviors from DIDSON records. Metrics related to predator and prey group size, prey responses to predation, predation rate, predator strategies, and the nonrandom use of landscape features by both predator and prey are described. In addition, relationships between patterns in these attributes are tested and issues regarding sampling strategies for future studies are discussed. We suggest that approaches combining direct visual observation and acoustic sampling at multiple scales are required to quantify variation in these relationships across underwater landscapes.
Keywords: predator, prey, behavior, reef, hydroacoustics
Introduction
Predation plays a critical role in the structure of reef fish communities (Tupper & Boutilier, 1997; Carr et al., 2002; Hixon & Beets, 2003). In addition to the direct effects on mortality of prey populations, predators also affect the distribution and behavior of cooccurring predators and prey species (Cosner et al., 1999). Predator-prey interactions are generally thought of most frequently in terms of direct mortality of prey and observed in the field using indirect methods such as stomach content sampling (e.g., Lindquist et al., 1994). Acoustic telemetry of muscle contraction rates (e.g., related to swimming speed) and stomach temperature have also been employed to infer patterns of feeding (Oswald, 1978; Sepulveda et al., 2004). Such indirect approaches are employed without regard to the more complex behavioral interactions between competing predators as well as between predators and prey, and their surrounding habitat that ultimately mediate predation success (but see Crowder et al., 1997). However, indirect methods cannot identify other important variables that influence predation dynamics and the impacts they have on population and community structure (Dill et al., 2003) such as predator group composition, effects of predator abundance, variation in the functional roles of species, interactions with landscape features, distribution and behavior of prey, and indirect species interactions (between predators as well as between predator and prey). The nature of these interactions makes them difficult to observe in any direct fashion at ecologically relevant space and time scales.