18 research outputs found
International Whaling Commission–Southern Ocean GLOBEC/CCAMLR collaboration. Scientific Committee document SC/55/E10, International Whaling Commission, May-June 2003, Berlin, Germany
Collaboration between the International Whaling Commission, and national programs conducting multidisciplinary ecosystem research in the Antarctic under Southern Ocean Global Ecosystem Dynamics (SO GLOBEC) program and the Commission for the Convention on Antarctic Marine Living Resources (CCAMLR) occurred during five research cruises between April 2002 and April 2003. Visual survey, passive acoustic and tissue biopsy work was conducted by IWC observers and collaborating passive acoustics scientists. Reported here are the preliminary results from these cruises: mapped distribution patterns of cetaceans from visual survey sighting data; individual photo identification records; species identification and positions of animals recorded on sonobuoys; and descriptions of environmental conditions observed or recorded as part of the multidisciplinary effort
Spatial and temporal occurrence of killer whale ecotypes off the outer coast of Washington State, USA
Three killer whale Orcinus orca ecotypes inhabit the northeastern Pacific: residents, transients, and offshores. To investigate intraspecific differences in spatial and temporal occur-rence off the outer coast of Washington State, USA, 2 long-term acoustic recorders were deployed from July 2004 to August 2013: one off the continental shelf in Quinault Canyon (QC) and the other on the shelf, off Cape Elizabeth (CE). Acoustic encounters containing pulsed calls were analyzed for call types attributable to specific ecotypes, as no calls are shared between ecotypes. Both sites showed killer whale presence year-round, although site CE had a higher number of days with en- counters overall. Transients were the most common ecotype at both sites and were encountered mainly during the spring and early summer. Residents were encountered primarily at site CE and showed potential seasonal segregation between the 2 resident communities, with northern resi- dents present mainly during summer and early fall when southern residents were not encountered. Offshore encounters were higher at site QC, with little evidence for seasonality. Spatial and temporal variability of residents and transients matches the distribution of their prey and can potentially be used for further inferences about prey preferences for different transient groups
Recommended from our members
Baleen whale spatial patterns in the Scotia Sea during January and February 2003
Different species of baleen whales display distinct spatial distribution patterns in the Scotia Sea during the austral summer. Passive acoustic and visual surveys for baleen whales were conducted aboard the RRS James Clark Ross in the Scotia Sea and around South Georgia in January and February 2003. Identified calls from four species were recorded during the acoustic survey including southern right (Eubalaena australis), blue (Balaenoptera musculus), fin (B. physalus) and humpback whales (Megaptera novaeangliae). These acoustic data included up calls made by southern right whales, downswept D and tonal calls by blue whales, two possible types of fin whale downswept calls and humpback whale moans and grunts. Visual detections included southern right, fin, humpback and Antarctic minke whales (B. bonaerensis sp.). Most acoustic and visual detections occurred either around South Georgia (southern right and humpback whales) or south of the southern boundary of the Antarctic Circumpolar Current (ACC) and along the outer edge of the ice pack (southern right, blue, humpback and Antarctic minke whales). Fin whales were the exception, being the only species acoustically and visually detected primarily in the central Scotia Sea, along the southern ACC front. In addition to identifiable calls from these species, two types of probable baleen whale calls were detected: 50Hz upswept and pulsing calls. It is proposed that minke whales may produce the pulsing calls, based on their similarities with minke whale calls recorded in the North Atlantic Ocean. There was an overlap between locations of fin whale sightings and recordings and locations of 50Hz upswept calls in the central Scotia Sea, but these calls were most similar to calls attributed to blue whales in other parts of Antarctica. More study is required to determine if baleen whales produce these two call types, and if so, which species. The efficiency of acoustics and visual surveys varied by species, with blue whales being easier to detect using acoustics, Antarctic minke whales being best detected during visual surveys and other species falling in between these two extremes
Marine mammal demographics of the outer Washington coast during 2008 -- 2009
In 2007 it was proposed that the U.S. Navy's Quinault Underwater Tracking Range (QUTR) off the outer Washington coast be expanded into deep water habitats (used by beaked and sperm whales) and along the coastal shelf (where coastal cetaceans forage). In 2004 an acoustic and visual monitoring effort was initiated within the boundaries of the expanded QUTR to characterize the vocalizations of marine mammal species present in the area, to determine the year-round seasonal presence of all odontocete and mysticete whales, and to evaluate the distribution of cetaceans near the Navy range. Acoustic data have been collected at two sites using autonomous High-frequency Acoustic Recording Packages (HARPs). This report summarizes acoustic data collected from June 2008 to June 2009. Seasonal occurrence and relative abundance of species consistently identified in the acoustic data are discussed in the context of earlier visual and acoustic data collections.N00244-8-1-0023
Recommended from our members
Temporal separation of two fin whale call types across the eastern North Pacific
Fin whales (Balaenoptera physalus) producea variety of low-frequency, short-duration, frequencymodulatedcalls. The differences in temporal patterns betweentwo fin whale call types are described from long-termpassive acoustic data collected intermittently between 2005and 2011 at three locations across the eastern North Pacific:the Bering Sea, off Southern California, and in Canal deBallenas in the northern Gulf of California. Fin whale callswere detected at all sites year-round, during all periodswith recordings. At all three locations, 40-Hz calls peakedin June, preceding a peak in 20-Hz calls by 3–5 months.Monitoring both call types may provide a more accurateinsight into the seasonal presence of fin whales across theeastern North Pacific than can be obtained from a singlecall type. The 40-Hz call may be associated with a foragingfunction, and temporal separation between 40- and 20-Hzcalls may indicate the separation between predominatelyfeeding behavior and other social interactions
Seasonality of blue and fin whale calls and the influence of sea ice in the Western Antarctic Peninsula
The calling seasonality of blue (Balaenoptera musculus) and fin (B. physalus) whales was assessed using acoustic data recorded on seven autonomous acoustic recording packages (ARPs) deployed from March 2001 to February 2003 in the Western Antarctic Peninsula. Automatic detection and acoustic power analysis methods were used for determining presence and absence of whale calls. Blue whale calls were detected year round, on average 177 days per year, with peak calling in March and April, and a secondary peak in October and November. Lowest calling rates occurred between June and September, and in December. Fin whale calling rates were seasonal with calls detected between February and June (on average 51 days/year), and peak calling in May. Sea ice formed a month later and retreated a month earlier in 2001 than in 2002 over all recording sites. During the entire deployment period, detected calls of both species of whales showed negative correlation with sea ice concentrations at all sites, suggesting an absence of blue and fin whales in areas covered with sea ice. A conservative density estimate of calling whales from the acoustic data yields 0.43 calling blue whales per 1000 n mi2 and 1.30 calling fin whales per 1000 n mi2, which is about one-third higher than the density of blue whales and approximately equal to the density of fin whales estimated from the visual surveys.<br /
Seasonal variability in whale encounters in the Western Antarctic Peninsula
Cetacean sighting surveys were conducted as part of nine multidisciplinary research cruises over late summer, autumn and winter of 2 years (2001–2003) during the Southern Ocean Global Ocean Ecosystems (SO GLOBEC) program. Sea-ice cover differed markedly between years, with apparent effects on cetacean distribution. No ice was present until late June in 2001, while the previous winter sea ice never fully retreated (>30% cover) during the 2002 or 2003 summer, thus increasing the proportion of thicker and more complex ice, including multi-year floes. Humpback (237 sightings; 537 individuals) and minke (103 sightings: 267 individuals) whales were the most commonly detected species. Data from seven comparable cruises were used to identify habitat for minke and humpback whales over five geographically distinct spatial divisions in the study area. In all years, both species were predominantly found in near coastal habitat, particularly in the fjords where complex habitat likely concentrated prey. In 2002 and 2003 the presence of sea ice provided additional feeding habitat, and the numbers of minkes (in winter) and humpbacks (late summer and autumn) in the area doubled compared with 2001. Humpbacks in particular were concentrated at the ice boundaries during late summer and autumn, while minke numbers increased in the winter that followed and occupied ice-covered areas along the entire shelf edge. Important resource sites for these species are mainly located in near-coastal areas and are used in all years, but when ice margins exist and intersect with resource sites they attract much larger numbers of animals due to the dynamics between sea ice and prey.<br /
BLUE WHALE VISUAL AND ACOUSTIC ENCOUNTER RATES IN THE SOUTHERN CALIFORNIA BIGHT
The relationship between blue whale (Balaenoptera musculus) visual and acoustic encounter rates was quantitatively evaluated using hourly counts of detected whales during shipboard surveys off southern California. Encounter rates were estimated using temporal, geographic, and weather variables within a generalized additive model framework. Visual encounters (2.06 animals/h, CV = 0.10) varied with subregion, Julian day, time of day, and year. Acoustic encounters of whales producing pulsed A and tonal B call sequences (song; 0.65 animals/h, CV = 0.06) varied by Julian day, survey mode (transit or stationary), and subregion, and encounters of whales producing downswept (D) calls (0.41 animals/h, CV=0.09) varied by Julian day and the number of animals seen. Inclusion of Julian day in all models reflects the seasonal occurrence of blue whales off southern California; however, the seasonal peak in visual encounters and acoustic encounters of D calling whales (July–August) was offset from the peak in acoustic encounters of singing whales (August–September). The relationship between visual and acoustic encounter rates varied regionally, with significant differences in several northern regions. The number of whales heard D calling was positively related to the number of animals seen, whereas the number of singing whales was not related to visual encounter rate