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At least ten species of beaked whales inhabit the North Pacific, but little is known about their abundance, ecology, and behavior, as they are elusive and difficult to distinguish visually at sea. Six of these species produce known species-specific frequency modulated (FM) echolocation pulses: Baird's, Blainville's, Cuvier's, Deraniyagala's, Longman's, and Stejneger's beaked whales. Additionally, one described FM pulse (BWC) from Cross Seamount, Hawai'i, and three unknown FM pulse types (BW40, BW43, BW70) have been identified from almost 11 cumulative years of autonomous recordings at 24 sites throughout the North Pacific. Most sites had a dominant FM pulse type with other types being either absent or limited. There was not a strong seasonal influence on the occurrence of these signals at any site, but longer time series may reveal smaller, consistent fluctuations. Only the species producing BWC signals, detected throughout the Pacific Islands region, consistently showed a diel cycle with nocturnal foraging. By comparing stranding and sighting information with acoustic findings, we hypothesize that BWC signals are produced by ginkgo-toothed beaked whales. BW43 signal encounters were restricted to Southern California and may be produced by Perrin's beaked whale, known only from Californian waters. BW70 signals were detected in the southern Gulf of California, which is prime habitat for Pygmy beaked whales. Hubb's beaked whale may have produced the BW40 signals encountered off central and southern California; however, these signals were also recorded off Pearl and Hermes Reef and Wake Atoll, which are well south of their known range.

At least ten species of beaked whales inhabit the North Pacific, but little is known about their abundance, ecology, and behavior, as they are elusive and difficult to distinguish visually at sea. Six of these species produce known species-specific frequency modulated (FM) echolocation pulses: Baird's, Blainville's, Cuvier's, Deraniyagala's, Longman's, and Stejneger's beaked whales. Additionally, one described FM pulse (BWC) from Cross Seamount, Hawai'i, and three unknown FM pulse types (BW40, BW43, BW70) have been identified from almost 11 cumulative years of autonomous recordings at 24 sites throughout the North Pacific. Most sites had a dominant FM pulse type with other types being either absent or limited. There was not a strong seasonal influence on the occurrence of these signals at any site, but longer time series may reveal smaller, consistent fluctuations. Only the species producing BWC signals, detected throughout the Pacific Islands region, consistently showed a diel cycle with nocturnal foraging. By comparing stranding and sighting information with acoustic findings, we hypothesize that BWC signals are produced by ginkgo-toothed beaked whales. BW43 signal encounters were restricted to Southern California and may be produced by Perrin's beaked whale, known only from Californian waters. BW70 signals were detected in the southern Gulf of California, which is prime habitat for Pygmy beaked whales. Hubb's beaked whale may have produced the BW40 signals encountered off central and southern California; however, these signals were also recorded off Pearl and Hermes Reef and Wake Atoll, which are well south of their known range.

Beaked whale echolocation signals are mostly frequency-modulated (FM) upsweep pulses and appear to be species specific. Evolutionary processes of niche separation may have driven differentiation of beaked whale signals used for spatial orientation and foraging. FM pulses of eight species of beaked whales were identified, as well as five distinct pulse types of unknown species, but presumed to be from beaked whales. Current evidence suggests these five distinct but unidentified FM pulse types are also species-specific and are each produced by a separate species. There may be a relationship between adult body length and center frequency with smaller whales producing higher frequency signals. This could be due to anatomical and physiological restraints or it could be an evolutionary adaption for detection of smaller prey for smaller whales with higher resolution using higher frequencies. The disadvantage of higher frequencies is a shorter detection range. Whales echolocating with the highest frequencies, or broadband, likely lower source level signals also use a higher repetition rate, which might compensate for the shorter detection range. Habitat modeling with acoustic detections should give further insights into how niches and prey may have shaped species-specific FM pulse types.

Beaked whale echolocation signals are mostly frequency-modulated (FM) upsweep pulses and appear to be species specific. Evolutionary processes of niche separation may have driven differentiation of beaked whale signals used for spatial orientation and foraging. FM pulses of eight species of beaked whales were identified, as well as five distinct pulse types of unknown species, but presumed to be from beaked whales. Current evidence suggests these five distinct but unidentified FM pulse types are also species-specific and are each produced by a separate species. There may be a relationship between adult body length and center frequency with smaller whales producing higher frequency signals. This could be due to anatomical and physiological restraints or it could be an evolutionary adaption for detection of smaller prey for smaller whales with higher resolution using higher frequencies. The disadvantage of higher frequencies is a shorter detection range. Whales echolocating with the highest frequencies, or broadband, likely lower source level signals also use a higher repetition rate, which might compensate for the shorter detection range. Habitat modeling with acoustic detections should give further insights into how niches and prey may have shaped species-specific FM pulse types.

This report summarizes work conducted in FY2009-FY2010 to characterize marine mammal sounds related to passive acoustic monitoring in the Hawaii Range Complex. Existing acoustic data from the Complex were analyzed to provide better descriptions of acoustic signals by species. Recordings were from a boat-based hydrophone or an autonomous bottom-moored High-frequency Acoustic Recording Package (HARP). Recordings were made of pygmy killer whales, melon-headed whales, Risso's dolphins, and rough-toothed dolphins. Echolocation click parameters were calculated for single species recordings during visual and acoustic surveys by boat-based hydrophones, and by using sightings from small boat surveys and locations of satellite tagged individuals near the HARP. Automatic classification of echolocation clicks of false killer whales and short-finned pilot whales was performed using a Gaussian mixture model. An analyst manually screened the HARP data collected off the west coast of Hawaii during the period ii/10/2009-iii/9/2009. Distinct call types were found for: beaked whales with frequency modulated upsweep echolocation pulses; sperm whales; high frequency clicks of unknown origin; low frequency banded echolocation clicks; and a large number of unidentified echolocation clicks. Odontocetes were acoustically active every day. Beaked whales were detected on 41% of recording days, but only briefly each day., The original document contains color images.

This report summarizes work conducted in FY2009-FY2010 to characterize marine mammal sounds related to passive acoustic monitoring in the Hawaii Range Complex. Existing acoustic data from the Complex were analyzed to provide better descriptions of acoustic signals by species. Recordings were from a boat-based hydrophone or an autonomous bottom-moored High-frequency Acoustic Recording Package (HARP). Recordings were made of pygmy killer whales, melon-headed whales, Risso's dolphins, and rough-toothed dolphins. Echolocation click parameters were calculated for single species recordings during visual and acoustic surveys by boat-based hydrophones, and by using sightings from small boat surveys and locations of satellite tagged individuals near the HARP. Automatic classification of echolocation clicks of false killer whales and short-finned pilot whales was performed using a Gaussian mixture model. An analyst manually screened the HARP data collected off the west coast of Hawaii during the period ii/10/2009-iii/9/2009. Distinct call types were found for: beaked whales with frequency modulated upsweep echolocation pulses; sperm whales; high frequency clicks of unknown origin; low frequency banded echolocation clicks; and a large number of unidentified echolocation clicks. Odontocetes were acoustically active every day. Beaked whales were detected on 41% of recording days, but only briefly each day.

This report summarizes work conducted in FY2009-FY2010 to characterize marine mammal sounds related to passive acoustic monitoring in the Hawaii Range Complex. Existing acoustic data from the Complex were analyzed to provide better descriptions of acoustic signals by species. Recordings were from a boat-based hydrophone or an autonomous bottom-moored High-frequency Acoustic Recording Package (HARP). Recordings were made of pygmy killer whales, melon-headed whales, Risso's dolphins, and rough-toothed dolphins. Echolocation click parameters were calculated for single species recordings during visual and acoustic surveys by boat-based hydrophones, and by using sightings from small boat surveys and locations of satellite tagged individuals near the HARP. Automatic classification of echolocation clicks of false killer whales and short-finned pilot whales was performed using a Gaussian mixture model. An analyst manually screened the HARP data collected off the west coast of Hawaii during the period ii/10/2009-iii/9/2009. Distinct call types were found for: beaked whales with frequency modulated upsweep echolocation pulses; sperm whales; high frequency clicks of unknown origin; low frequency banded echolocation clicks; and a large number of unidentified echolocation clicks. Odontocetes were acoustically active every day. Beaked whales were detected on 41% of recording days, but only briefly each day., CNO(N45), N00244-08-1-0028

This report summarizes work conducted in FY2009-FY2010 to characterize marine mammal sounds related to passive acoustic monitoring in the Hawaii Range Complex. Existing acoustic data from the Complex were analyzed to provide better descriptions of acoustic signals by species. Recordings were from a boat-based hydrophone or an autonomous bottom-moored High-frequency Acoustic Recording Package (HARP). Recordings were made of pygmy killer whales, melon-headed whales, Risso's dolphins, and rough-toothed dolphins. Echolocation click parameters were calculated for single species recordings during visual and acoustic surveys by boat-based hydrophones, and by using sightings from small boat surveys and locations of satellite tagged individuals near the HARP. Automatic classification of echolocation clicks of false killer whales and short-finned pilot whales was performed using a Gaussian mixture model. An analyst manually screened the HARP data collected off the west coast of Hawaii during the period ii/10/2009-iii/9/2009. Distinct call types were found for: beaked whales with frequency modulated upsweep echolocation pulses; sperm whales; high frequency clicks of unknown origin; low frequency banded echolocation clicks; and a large number of unidentified echolocation clicks. Odontocetes were acoustically active every day. Beaked whales were detected on 41% of recording days, but only briefly each day.