[MARMAM] Journal of Cetacean Research and Management - abstracts - latest issue (2008; vol 10, issue 1)
dagmar_fertl at hotmail.com
Wed Jan 28 20:29:27 PST 2009
Dear Marmam and ECS-mailbase subscribers,
Apologies to those of you who will receive duplicate emails due to cross-posting. The International Whaling Commission (IWC) publishes The Journal of Cetacean Research and Management thrice yearly (Spring, Autumn, and Winter), with at least one supplement that will contain the full report of the IWC Scientific Committee. The following is posted on behalf of the IWC and the journal editor. Further information can be found at: http://www.iwcoffice.org/publications/JCRM.htm. A guide for authors is included in the first volume of each issue and on the IWC website: http://www.iwcoffice.org/publications/authorsguide.htm.
Contact information is provided for the corresponding author for each article. Please do not contact the listserve editors or me for pdfs or copies of the articles. Thank you for your continued interest in the journal and abstract postings.
Kemper, C., D. Coughran, R. Warneke, R. Pirzl, M. Watson, R. Gales, and S. Gibbs. 2008. Southern right whale (Eubalaena australis) mortalities and human interactions in Australia, 1950-2006. Journal of Cetacean Research and Management 10 (1):1-8.
Contact e-mail: Kemper.Cath at saugov.sa.gov.au
A total of 44 records of southern right whale mortalities and non-fatal anthropogenic interactions have been documented in Australia by museums, wildlife agencies and researchers since 1950. Sixteen of the events involved whales that apparently survived. Events were recorded in all months except January and 65% occurred in the period July to October. Mortalities were more numerous in the western half of the continent where southern right whales are more frequently observed. Events were classified according to their outcome and nature: carcasses (with no evidence of human interaction) n=25, fatal entanglements n=1, non-fatal entanglements n=12, fatal vessel collisions n=2, non-fatal vessel collisions n=3, non-fatal shooting n=1. No live strandings were recorded. The number of both mortalities and non-fatal anthropogenic incidents has increased 4-fold since the mid 1970s. More calves than ‘non-calf’ whales were present in the carcass category, whereas the opposite was the case for events involving human interaction. Lines, nets and buoys used in fishing crustaceans (rock-lobster, crab) were associated with several entanglements (n=5). A longline entanglement of a 14m female resulted in a chronic injury, debilitation and death. As a proportion of the total records for each region, there were fewer vessel collisions of right whales in Australia (11%) than in South Africa (16%) or the North Atlantic (35%).
Gilpatrick, Jr., J.W., and W.L. Perryman. 2008. Geographic variation in external morphology of North Pacific and Southern Hemisphere blue whales (Balaenoptera musculus). Journal of Cetacean Research and Management 10(1):9-21.
Contact e-mail: jim.gilpatrick at noaa.gov
Geographic variations in size and proportions of blue whales (Balaenoptera musculus) were investigated using length data acquired from whaling records and aerial photogrammetric surveys. Results showed that blue whales found in the eastern Pacific off Central and North America are significantly shorter (by approximately 2m) than blue whales found at higher latitudes in the North Pacific. Results support the occurrence of a morphologically distinct eastern North Pacific (ENP) blue whale population which migrates in spring/summer from warm waters off Central America and Mexico to temperate feeding grounds along the west coast of North America. Southern Hemisphere blue whales sampled with vertical aerial photogrammetry off northern Peru and the Galapagos Islands were similar in size to the ENP blue whales. However, the population affinity of these southern blue whales remains uncertain. No length data were available for blue whales formerly captured off southern Japan and Korea. Nonetheless, a history of diminishing fishery catches and a lack of any recent sightings suggests that these whales were members of a geographic population that is now severely depleted or extinct. Based on comparisons of total length, length of rostrum and length of tail region, ENP blue whales were found to be morphologically similar to the ‘pygmy’ blue whale (B.m. brevicauda) described from the Kerguelen Island region of the southern Indian Ocean. ‘Antarctic’ blue whales (B.m. intermedia) from the Southern Ocean were found to be statistically significantly larger than their conspecifics at high latitudes in the North Pacific. These results support the hypotheses that blue whales that migrate from warm seas to cold feeding grounds in high latitudes are larger than those whose distributions are limited to low and mid-latitudes. Differences in morphology may reflect selective pressure on populations to adapt physiologically to energy demands associated with different migration, environmental and ecological regimes. As some of the results come from populations located far apart in different oceans, questions remain concerning the continuity of populations within and among ocean basins. Consequently, research using fishery data and approaches such as photogrammetry, telemetry, acoustics and molecular genetic analysis should be continued to better understand the worldwide blue whale population structure.
Boisseau, O., D. Gillespie, R. Leaper, and A. Moscrop. 2008. Blue (Balaenoptera musculus) and fin (B. physalus) whale vocalizations measured from northern latitudes of the Atlantic Ocean. Journal of Cetacean Research and Management 10(1):23-30.
e-mail: oboisseau at ifaw.org
Vocalizations were recorded in the vicinity of sighted blue whales (Balaenoptera musculus) and fin (B. physalus) in the North Atlantic between Iceland and Greenland in August 2004 from a hydrophone towed behind a research vessel and from free floating sonobuoys. The structures of recorded calls were broadly similar to those reported from other areas, but lacked the stereotypical patterning of those signals though to represent reproductive displays. Counts of non-patterned blue whale calls indicated low vocalization rates, with a mean of 0.62 phrases per whale per hour (0.12 A-B and 0.49 arch phrases per whale per hour). However, vocalizations were highly clustered in time, with 80% of blue whale calls ascribed to the focal animals arriving within a single 80 second period. It is not clear what behavioural, geographical or seasonal trends may influence the vocalization rate of large baleen whales, and thus direct comparisons between areas are difficult. However, it is hoped the results presented will be of use in interpreting remote recordings of blue whales made from the North Atlantic. Hydrophones were also monitored continuously over 7,757km of trackline using an automated detection algorithm developed for North Atlantic right whales (Eubalaena glacialis). However, no North Atlantic right whales were seen or heard during the study period.
Flach, L., P. Amaral Flach, and A.G. Chiarello. 2008. Density, abundance and distribution of the guiana dolphin, (Sotalia guianensis van Benéden, 1864) in Sepetiba Bay, southeast Brazil. Journal of Cetacean Research and Management 10(1):31-36.
Contact e-mail: flachleo at hotmail.com
Line transect surveys were conducted from August 2002 to July 2003 to examine the abundance and distribution of the guiana (Sotalia guianensis) in Sepetiba Bay-Southeast Brazil. A boat-based platform and 50 pre-determined line transects were used to assess the population on two main stratum-specific environments of the bay (entrance and interior). A total of 3,140km of transects were surveyed at 12-15km-hr^-1 and good sea conditions (Beaufort 0-2), resulting in 157 sightings of dolhin groups and 129 sightings after truncation of all sightings beyond 400m. From the 129 sightings, the DISTANCE program generated a population density of 2,79 dolphins km^-2 and calculated a population of 1,269 individuals (CV=739-2,196) for the bay. Sighting frequency (n=126 or 80.3%) was higher at the entrance of the bay compared with the interior (n=31 or 19.7%), although the density and abundance were similar for the entrance (2,91 dolphins km^-2 and 596 dolphins) and interior (2,69 dolphins km^-2 and 672 dolphins). Results reveal an important population of guiana dolphins at Sepetiba Bay, the largest thus far studied off the South American coast, stressing the importance of the area for the conservation of this species. The study also indicated that line-transect sampling carried out from small boats in large bays can produce statistically robust estimates and therefore could be recommended for population monitoring in other areas of the Brazilian coast with similar characteristics.
Smith, B.D., and M. Than Tun. 2008. A note on the species occurrence, distributional ecology and fisheries interactions of cetaceans in the Mergui (Myeik) Archipelago, Myanmar. Journal of Cetacean Research and Management 10(1):37-44.
Contact e-mail: bsmith at wcs.org
A vessel-based line-transect survey for cetaceans conducted during 23 February-6 March 2005 of the nearshore waters (to a depth of 40-60m) of the Mergui (Myeik) Archipelago of southern Myanamar searched along 955km of trackline resulting in 30 cetacean sightings. These included Indo-Pacific bottlenose dolphins Tursiops aduncus (n=15), Indo-Pacific humpback dolphins Sousa chinensis (n=3), spinner dolphins Stenella longirostris (n=4; the largest of these was mixed with pantropical spotted dolphins Stenella attenuata), Irrawaddy dolphins Orcaella brevirostris (n=1), finless porpoises Neophocaeana phocaenoides (n=1), Bryde’s whales Balaenoptera edeni/brydei (identification tentative; n=1), one unidentified baleen whale (probably also a Bryde’s whale) and four unidentified delphinid groups. Irrawaddy dolphins and finless porpoises were found in shallow, brackish waters, Indo-Pacific humpback dolphins also in shallow waters but those less affected by freshwater inputs and Bryde’s whales and Indo-Pacific bottlenose, spinner and spotted dolphins in deeper and clearer waters. In total 2,5645 gill netters/long liners (95% CI=1,228-3,903), 1,301 squid jiggers (95% CI=611=1,992) and 532 stern trawlers (95% CI=154-910) were estimated to be operating in the study area. Concentrations of gill netters/long liners were particularly high in shallow nearshore waters and at least 150 were operating in the bay where the only sightings of Irrawaddy dolphins and finless porpoises were made. There is a need to better assess nearshore cetacean populations, investigate whether or not incidental and intentional catches are sustainable and incorporate a cetacean element into an initiative to establish a marine protected area network in the Mergui Archipelago.
Smith, B.D., B. Ahmed, R. Mansur Mowgli, and S. Strindberg. 2008. Species occurrence and distributional ecology of nearshore cetaceans in the Bay of Bengal, Bangladesh, with abundance estimates for Irrawaddy dolphins Orcaella brevirostris and finless porpoises Neophocaena phocaenoides. Journal of Cetacean Research and Management 10(1):45-58.
Contact e-mail: bsmith at wcs.org
A vessel-based line-transect survey for cetaceans conducted during February 2004 along 1,018km of systematic trackline in the nearshore waters of Bangladesh in 111 ‘on-effort’ cetacean sightings including: Irrawaddy dolphins, Orcaella brevirostris (n=75, mean group size=2.2); finless porpoises, Neophocaena phocaenoides (n=11, mean group size=2.6); Indo-Pacific humpback dolphins, Sousa chinensis (chinensis-form; n=6, mean group size=16.2); Indo-Pacific bottlenose dolphins, Tursiops aduncus (n=3, mean group size=36.1); pantropical spotted dolphins, Stenella attenuata (n=1, best, high and low group size estimates=800, 1,100, and 600, respectively); Bryde’s whales, Balaenoptera edeni/brydei (large-form; n=1, three individuals); and unidentified small cetaceans (n=14). Cetacean distribution was closely tied to environmental gradients, with Irrawaddy dolphins and finless porpoises occurring most often in nearshore, turbid, low-salinity waters, Indo-Pacific humpback dolphins in slightly deeper waters where the colour turned from brown to green and Indo-Pacific bottlenose dolphins and Bryde’s whales in deep, clear, high-salinity waters of the Swatch-of-No-Ground (SoNG), a 900+m-deep submarine canyon that extends within about 40km of the Sundarbans mangrove forest. A Generalised Additive Model of environmental and presence-absence data indicated that Irrawaddy dolphin distribution was conditionally dependent (p<0.05) on low salinity and shallow depth, which explained 36% of the variance. A distance analysis of Irrawaddy dolphin and finless porpoise sightings resulted in abundance estimates of 5,383 (CV=39,5) and 1,382 (CV=54,8%), respectively. The positive conservation implications of these abundance estimates were tempered by observations of potentially unsustainable bycatch in gillnet fisheries targeting elasmobranches and scarring on bottlenose dolphins consistent with trawl fishery interactions. The nearshore waters of Bangladesh support a taxonomically diverse and relatively abundant cetacean fauna, which can probably be explained by the wide variety of environmental gradients (river-sea and shallow-deep) available within a relatively small area and the enormous biological production driven by extreme fluvial and oceanographic processes. Priority recommendations for future research include: (1) evaluating bycatch levels and the types of fishing gears responsible for incidental kills; (2) investigating the spatial and temporal dynamics of high-density cetacean hotspots; (3) resolving the species and population identities of baleen whales and delphinids occurring in the SoNG; and (4) assessing the abundance, movement patterns and fishery interactions of Indo-Pacific bottlenose dolphins.
Johnston, D.W., J. Robbins, M.E. Chapla, D.K. Mattila, and K.R. Andrews. 2008. Diversity, habitat associations and stock structure of odontocete cetaceans in the waters of American Samoa, 2003-2006. Journal of Cetacean Research and Management 10(1):59-66.
Contact e-mail: david.johnston at duke.edu
Little is known about the species composition, distribution, abundance or stock structure of odontocetes in the central and western tropical Pacific Ocean, including those inhabiting the U.S. Exclusive Economic Zone (EEZ) waters of American Samoa. While some information on species presence in this region has been gleaned from anecdotal sightings and whaling and stranding records, odontocete diversity in the waters of American Samoa has never been formally investigated. This lack of information precludes efforts to determine the sustainability of cetacean populations within US EEZ waters. This paper reports on the first dedicated surveys to document the presence and distribution of odontocete cetaceans in the waters of American Samoa. A series of small-boat photo-identification and biopsy surveys for cetaceans were conducted in the nearshore waters of Tutuila during 2003-06. In addition, ship-based visual surveys were conducted in the waters surrounding the Manu’a Islands, Rose Atoll and Swains Island in summer 2006. A total of 58 groups of odontocete cetaceans were encountered during both small boat-based and ship-based surveys; spinner dolphins (Stenella longirostris, n=34), rough-toothed dolphins (Steno bredanensis, n=10), sperm whales (Physeter macrocephalus, n=3), false killer whales (Pseudorca crassidens, n=5), bottlenose dolphins (Tursiops truncatus, n=1), dwarf sperm whales (Kogia sima, n=1), short-finned pilot whales (Globicephala macrorhynchus, n=1), and three groups of unidentified odontocetes. Photographs were analysed for quality and individuals with distinctive markings were selected for entry into a photo-identification catalogue. The resultant catalogue included 46 spinner dolphins, 41 rough-toothed dolphins, 2 bottlenose dolphins, 5 false killer whales, 4 pilot whales, 1 dwarf sperm whale and 4 sperm whales. Thirteen spinner dolphins and 14 rough-toothed dolphins were sighted in multiple years. To investigate stock structure, spinner dolphin genetic data were used to compare mitochondrial genetic diversity and allele frequencies between American Samoa and the Hawaiian Islands. American Samoa had a higher genetic diversity, and populations at the two locations were genetically distinct (ΦST=0.21). The high diversity at American Samoa indicates that spinner dolphins at this location are not reproductively isolated, but the data do not rule out the possibility that these dolphins may be demographically isolated on ecological timescales.
Ohishi, K., Y. Fujise, and T. Maruyama. 2008. Brucella spp. in the western North Pacific and Antarctic cetaceans: A review. Journal of Cetacean Research and Management 10(1):67-72.
Contact e-mail: oishik at jamstec.go.jp
Brucella spp. has been reported in a variety of marine mammals worldwide. Serological and pathological studies were conducted on Brucella spp. in the western North Pacific using samples from three whale species during 2000 under the second phase of the Japanese Whale Research Program under Special Permit in the Western North Pacific (JARPN II). Serum samples from 40 common minke whales (Balaenoptera acutorostrata), 43 Bryde’s whales (B. edeni) and 4 sperm whales (Physeter macrocephalus) were assessed with agglutination testing designed from B. abortus detection. Brucella-specific serum antibodies were detected in 38% of common minke whale samples. A lower prevalence (9%) of the antibody was observed for the Bryde’s whale samples, whereas no specific antibody against Brucella was observed for the four sperm whales. Serum samples from 104 Antarctic minke whales (B. bonarensis) collected under the Japanese Whale Research Program under the Special Permit in the Antarctic (JARPA) were analysed, and no Brucella-specific antibodies were detected. Granular lesions with caseation and mineralisation were found in 35% (13 males and one female) of 40 minke whale gonads. Similar lesions were also observed in the gonads of one male and one female Bryde’s whale. These gonad lesions were found in 440 Antarctic minke whales and five sperm whales, despite the thorough examination conducted for reproduction studies. Histopathological studies showed that the lesions consisted of epithelioid cells, multinucleated giant cells and had an infiltration of lymphocytes. DNA fragments were amplified by PCR using specific primers from ten of 22 abnormal testis tissues collected from common minke whales. The DNA sequences had IS711 transposable elements downstream of bp26, characteristics of marine strains of Brucella spp. The gene structure of omp2, and specific PCR products for seal strains, showed similarity to Atlantic seal strains rather than Atlantic whale strains. This showed that classification based on marine mammal host species, B. cetacean and B. pinippedia is not appropriate. Considering the zoonotic nature of the genus Brucella, the crews and researchers who have had frequent contact with whales were serologically examined and found to have no health issues associated with this agent. No Brucella-specific antibody was detected in the sera from 51 persons examined in 2001, nor from 103 examined issues in 2003.
Acevedo, R., L. Oviedo, N. Silva, and Bermúdez-Villapol. 2008. A note on the spatial and temporal distribution of humpback whale (Megaptera novaeangliae) off Venezuela, southeastern Caribbean. Journal of Cetacean Research and Management 10(1):73-79.
Contact e-mail: dolphinrag at yahoo.com
This paper presents information on the spatial and temporal distribution of humpback whales in Venezuela waters. Using a relational database containing information from the museums of Venezuela, published and unpublished records were incorporated into the Geographical Information System (MapInfo Professional 7.0). A total of 53 records were gathered, of which sightings made up 72%, followed by acoustic sampling (9%) intentional capture (6%), stranding (6%) and unknown records (8%). Humpback whales were mainly sighted over the continental shelf of the northeastern region in shallow waters of 0-100 m in depth. The date on which each record was made supports the austral winter months do not give conclusive proof that Southern Hemisphere humpback whales are present during this time, but lead to the hypothesis that whales migrate from Brazil. Systematic research effort (especially photo-identification) is recommended in order to better understand humpback whale movements, distribution and identity.
Brownell, Jr., R.L.*, D.P. Nowacek, and K. Ralls. 2008. Hunting cetaceans with sound: A worldwide review. Journal of Cetacean Research and Management 10(1):81-88.
contact email: Robert.Brownell at noaa.gov
Cetaceans are sensitive to a variety of anthropogenic sounds because they normally use sound to navigate, communicate and capture prey. This paper reviews some fisheries that have taken advantage of this sensitivity by using sound to help capture numerous species of dolphins and whales. Fishermen in many parts of the world have independently developed methods that use sounds to drive (herd) various species of small cetaceans so that they can be killed and used for food, culled (i.e. to offset competition for fish), help capture fish (e.g. in the Eastern Tropical Pacific) or be taken into captivity. It is well documented that drive fisheries for small cetaceans have occurred for at least 650 years in Japan and Europe. With respect to large whales, the use of sound became widespread after World War II, with the advent of an early form of sonar (ASDIC) which was used for hunting both baleen and sperm whales. Baleen whales displayed a strong avoidance reaction to ASDIC by swimming rapidly away from the sound while remaining near the surface of the water. In contrast, sperm whales made longer dives in response to ASDIC. During the 20th Century, fishermen using these two acoustical methods killed millions of cetaceans (including those caught in the Eastern Tropical Pacific tuna fisheries), both small and large. The effectiveness of acoustic capture methods shows that a wide range of cetacean species have strong avoidance reactions to a variety of anthropogenic sounds. Research to better document the characteristics of these sounds, including those used in existing drive fisheries and those produced by ASDIC devices, would improve understanding of the types of anthropogenic sounds that could contribute to mass-stranding events and should be minimised in protected habitats for cetaceans.
Weller, D.W.*, A.L. Bradford, H. Kato, T. Bando, S. Ohtani, A.M. Burdin, and R.L. Brownell, Jr. 2008. Photographic match of a western gray whale between Sakhalin Island, Russia, and Honshu, Japan: The first link between feeding ground and a migratory corridor. Journal of Cetacean Research and Management 10(1):89-91.
Contact email: Dave.Weller at noaa.gov
Between 2005 and 2007, four female western gray whales were accidentally entrapped and died in Japanese set nets while migrating along the Pacific coast of Honshu, Japan. Photographs of these animals were compared to a photo-identification catalogue of western gray whales from the feeding ground off Sakhalin Island, Russia, to look for matches of individuals between the two areas. Although useable quality photographs were available for only one of the four whales from Japan, a confirmed match was made to a whale photographed off Sakhalin Island. This match represents the first link between the feeding ground and a migratory corridor and highlights the importance of multinational research collaboration in the formation of range-wide conservation measures to protect this critically endangered population.
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