In 2015, Ferguson et al. coordinated an effort to define biologically important areas (BIA) for cetacean stocks in US waters, using a combination of information from the scientific literature, unpublished data, and expert knowledge. This information was then used to develop written narratives and an interactive map for each species or stock and their corresponding BIAs (seasonally or year-round). BIAs include areas that are important for migratory, reproductive, and feeding purposes, as well as areas used by small and resident (i.
False killer whales are long-lived apex predators, making them more susceptible to bioaccumulation of persistent organic pollutants. There are three genetically distanct stocks of false killer whales in the Hawaiian Islands: a pelagic, Northwestern Hawaiian Islands (NWHI), and main Hawaiian Islands (MHI) stock. The latter population is comprised of at least 4-5 cohesive social groups or “clusters”, consisting of highly-related and regularly-interacting individuals. The MHI stock was listed as “endangered” in 2012 in light of precipitous decline over recent decades.
Fish aggregating devices (FADs) are buoys that are designed to attract aggregations of pelagic fishes that naturally associate with floating objects; the purpose of FADs is to enhance fishermen’s catch. However, FADs may also attract false killer whales that pursue the same prey fishes, and consequently exacerbate the risk of harmful fisheries interactions. More broadly, this research will help discern whether FADs have an influence on false killer whale space use which ultimately informs our understanding of their occurrence and associated risk to anthropogenic activities.
Hawaiian waters are home to a population of false killer whales that primarily occupy insular regions of the islands. Following a precipitous decline observed over recent decades, this population was listed as “endangered” under the US Endangered Species Act in 2012. It is speculated that the greatest threat to this population are interactions with fisheries (through depredation) and bycatch. However, understanding the severity of bycatch issues requires both abundance estimates and rates at which bycatch and/or interactions occur.
Estimating individual received levels (RL) of sound during mid-frequency sonar activities requires knowledge of the location of the sound source (and level of sound emitted) and position of the focal individual. With the former already known, a sound propagation model is used to estimate sound levels through space and time while accounting for influences of static variables such as bathymetry. To obtain the animal’s position, satellite tags are deployed before sonar activities begin and locations are estimated via the Doppler effect and processed by Argos CLS location algorithms.
Genetic studies and sighting distributions were used to delineate four stocks of pantropical spotted dolphins in Hawaiian waters: a pelagic stock and insular stocks off Hawaiʻi, Maui Nui, and Oʻahu. Information on short-term movements and space use in Hawai‘i is limited, yet such information is critical to their conservation, particularly in light of recent documentation of frequent interactions between fishing vessels and spotted dolphins throughout the main Hawaiian Islands (Baird & Webster, 2020).