Eubalaena Japonica Research Articles

Demonstration of a basic mitochondrial enrichment method to produce the complete mitochondrial genome sequence of the endangered North Atlantic right whale (Eubalaena glacialis)

The North Atlantic right whale is one of only three species within the Eubalaena genus, a group heavily targeted by the whaling industry prior to the twentieth century. All three species (Eubalaena australis, Eubalaena japonica and Eubalaena glacialis) are CITES listed (Appendix I), with the latter two species listed as endangered (IUCN, v 2017-1). The mitochondrial genome of the first two species have been sequenced and are publicly available, while E. glacialis was unavailable. Here we present the complete mitochondrial genome sequence of E. glacialis, while also detailing a straight forward mitochondrial enrichment method that facilitates analysis using next generation sequencing. This method simultaneously allows for efficient sequencing of the mitochondrial genome, while demonstrating quality sequence coverage that is even across the genome. This enrichment illustrates a marked improvement in sequence depth compared to that achieved when performing whole genome sequencing using a standard DNA extraction.

Using nonlinear time warping to estimate North Pacific right whale calling depths in the Bering Sea.

Calling depth distributions are estimated for two types of calls produced by critically endangered eastern North Pacific right whales (NPRWs) in the Bering Sea, using passive acoustic data collected with bottom-mounted hydrophone recorders. Nonlinear time resampling of 12 NPRW "upcalls" and 20 "gunshots" recorded in a critical NPRW habitat isolated individual normal mode arrivals from each call. The relative modal arrival times permitted range estimates between 1 and 40 km, while the relative modal amplitudes permitted call depth estimates, provided that environmental inversions were obtained from high signal-to-noise ratio calls. Gunshot sounds were generally only produced at a few meters depth, while upcall depths clustered between 10 and 25 m, consistent with previously published bioacoustic tagging results from North Atlantic right whales. A Wilcoxon rank sum test rejected the null hypothesis that the mean calling depths of the two call types were the same (p = 2.9 × 10-5); the null hypothesis was still rejected if the sample set was restricted to one call per acoustic encounter (p = 0.02). Propagation modeling demonstrates that deeper depths enhance acoustic propagation and that source depth estimates impact both NPRW upcall source level and detection range estimates.

Abundance and distribution of cetaceans in the Gulf of Alaska

To effectively protect and manage marine mammals, contemporary information on their abundance and distribution is essential. Several factors influence present-day insight including the accessibility of the study area and the degree of difficulty in locating and studying target species. The offshore waters of the Gulf of Alaska are important habitat to a variety of cetaceans yet have remained largely unsurveyed due to its remote location, vast geographic area, and challenging environmental conditions. Between 2009 and 2015, three vessel surveys were conducted using line-transect sampling methods to estimate cetacean abundance and density. Here, we present results on the distribution for all species encountered and density and abundance for six species, including humpback whales (Megaptera novaeangliae), fin whales (Balaenoptera physalus), sperm whales (Physeter macrocephalus), blue whales (B. musculus), killer whales (Orcinus orca), and Dall’s porpoise (Phocoenoides dalli). Fin whales, humpback whales, and Dall’s porpoise were the most abundant species. Beaked whales were documented only in 2015. Prior to this study, recent sightings of blue whales were rare, likely related to the lack of offshore survey coverage. No North Pacific right whales (Eubalaena japonica) were sighted, underscoring the critically endangered status of this species in a formerly populous habitat. Although these results provide the first estimates from offshore waters, additional effort is necessary to assess trends and to obtain baseline data for the rare and cryptic species in order to better inform conservation and management actions.

Stereotyped, repetitive gunshot call patterns produced by the North Pacific right whale, Eubalaena japonica

The Marine Mammal Laboratory has deployed long-term passive acoustic recorders along the 50 m and 70 m isobaths throughout the Bering Sea since 2007. Instruments recorded at either 4 kHz on a ~7-11% duty cycle, or 8 kHz on a 30-45% duty cycle. In addition, directional sonobuoys were deployed during field surveys to allow real-time monitoring for large whale presence. During the 2010 survey, a stereotyped, repetitive gunshot call pattern was acoustically detected on sonobuoys. This same call pattern was then detected on two different long-term moored recorders in two separate years. Since then, six different stereotyped, repetitive patterns have been documented, three of which have been analyzed. Preliminary results show that each pattern has a minimum of 30 iterations repeated over several hours. Furthermore, in several cases, these patterns are repeated throughout the season, in consecutive years, and in one instance, in non-consecutive years. While male North Atlantic right whales produce long gunshot bouts similar to the reproductive advertisement known in other species, right whales are not known to produce any type of repeated stereotyped pattern. This represents the first study to document stereotyped repetitive gunshot patterning in right whales. [Work funded by the Bureau of Ocean Energy Management.]

Recent observations of critically endangered North Pacific right whales (Eubalaena japonica) off the west coast of Canada

The eastern North Pacific population of right whale (Eubalaena japonica) is considered to be one of the smallest whale populations in the world and is at serious risk of extirpation. During the past century, there have been only six records of North Pacific right whales off the west coast of Canada. All six were taken by whaling operations, the last in 1951. Two independent and extremely rare sightings of North Pacific right whales were made off the coast of British Columbia, Canada, in 2013. We describe observations made of these two whales and include information on prey and genetic identity for one individual. These sightings represent the first time this species has been confirmed in Canadian waters in 62 years, and likely the only time in the last 15 years that the species has been sighted south of the Kodiak Island area, Alaska, in the eastern North Pacific Ocean. It can be concluded that, although extremely rare, the species has not been extirpated from waters off Canada’s Pacific coast.

A spatially explicit estimate of the prewhaling abundance of the endangered North Atlantic right whale.

The North Atlantic right whale (NARW) (Eubalaena glacialis) is one of the world's most threatened whales. It came close to extinction after nearly a millennium of exploitation and currently persists as a population of only approximately 500 individuals. Setting appropriate conservation targets for this species requires an understanding of its historical population size, as a baseline for measuring levels of depletion and progress toward recovery. This is made difficult by the scarcity of records over this species' long whaling history. We sought to estimate the preexploitation population size of the North Atlantic right whale and understand how this species was distributed across its range. We used a spatially explicit data set on historical catches of North Pacific right whales (NPRWs) (Eubalaena japonica) to model the relationship between right whale relative density and the environment during the summer feeding season. Assuming the 2 right whale species select similar environments, we projected this model to the North Atlantic to predict how the relative abundance of NARWs varied across their range. We calibrated these relative abundances with estimates of the NPRW total prewhaling population size to obtain high and low estimates for the overall NARW population size prior to exploitation. The model predicted 9,075-21,328 right whales in the North Atlantic. The current NARW population is thus <6% of the historical North Atlantic carrying capacity and has enormous potential for recovery. According to the model, in June-September NARWs concentrated in 2 main feeding areas: east of the Grand Banks of Newfoundland and in the Norwegian Sea. These 2 areas may become important in the future as feeding grounds and may already be used more regularly by this endangered species than is thought.

Space use patterns of the endangered North Pacific right whale Eubalaena japonica in the Bering Sea

Understanding habitat use of critically endangered North Pacific right whales (NPRWs, Eubalaena japonica) is important to better evaluate the potential effects of anthro- pogenic activities and climate change on this species. Satellite transmitters were deployed on indi- vidual right whales in 2004, 2008 and 2009 to investigate whether their space-use patterns in the Southeastern Bering Sea (SEBS) were influenced by environmental conditions and to assess habi- tat use in areas of human interest. Whales were monitored for an average of 40 d (range 29�58 d) between July and October, a period in which they inhabited the SEBS shelf. Individuals tagged in 2008�2009 (cold years) remained in the middle shelf domain, travelled at a slower rate and showed a spatially more restricted habitat use than a whale tagged in 2004 (a warm year). Monte Carlo tests suggested that NPRWs associated with the cold pool (remnant winter water in the bot- tom layer of the middle shelf domain) during cold years, which is likely due to higher copepod abundance and reduced competition with other copepod predators within the cold pool. Teleme- try data indicated that a Critical Habitat designated by the US National Marine Fisheries Service encompasses the main feeding range of NPRWs in the Bering Sea. Two whales briefly visited the North Aleutian Basin, an area previously considered for oil and gas development. Small sample sizes precluded conclusive comparisons of space-use patterns among years with significantly dif- ferent temperature regimes, but we hypothesize that habitat use in the SEBS varies with these regimes because of concomitant changes in the abundance of the whales primary copepod prey. Long-term evaluation of space-use patterns of NPRWs is required to further understand their habits in the feeding grounds in light of global warming and the potential for increased anthro- pogenic activities.

Opportunistic sightings of the endangered North Pacific right whales (Eubalaena japonica) in Russian waters in 2003–2014

Opportunistic sightings of the endangered North Pacific right whales (<i>Eubalaena japonica</i>) in Russian waters in 2003–2014

North Pacific right whales (Eubalaena japonica) recorded in the northeastern Pacific Ocean in 2013

Notes MARINE MAMMAL SCIENCE, **(*): ***–*** (*** 2014) © 2014 The Authors. Marine Mammal Science published by Wiley Periodicals, Inc. on behalf of Society for Marine Mammalogy This is an open access article under the terms of the Creative Commons Attribution- NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made. DOI: 10.1111/mms.12189 North Pacific right whales (Eubalaena japonica) recorded in the northeastern Pacific Ocean in 2013 A NA S IROVI C , 1 S ARAH C. J OHNSON , L AUREN K. R OCHE , L EAH M. V ARGA , S EAN M. W IGGINS and J OHN A. H ILDEBRAND , Scripps Institution of Oceanography, University of California San Diego, 9500 Gilman Drive MC 0205, La Jolla, California 92093-0205, U.S.A. The North Pacific right whale (Eubalaena japonica) is among the most critically endangered marine mammals in the world (Brownell et al. 2001). Its population was drastically reduced by 19th and 20th century whaling and its recovery was addition- ally slowed by illegal Soviet whaling that occurred during the 1960s (Clapham et al. 2004, Ivashchenko and Clapham 2012). With a severe decrease in the population also came a restriction in range, from extensive distribution across the North Pacific, to a constricted presence of two different populations, one in the Sea of Okhotsk and along the Western Pacific, and the other in the eastern Bering Sea (Scarff 1986, Clap- ham et al. 2004, Josephson et al. 2008). The abundance estimates for the eastern pop- ulation are around 30 animals (Wade et al. 2006, 2011b; Marques et al. 2011), while the western population is considered to be larger with current estimates of probably no more than 300 animals (Brownell et al. 2001). Most baleen whales undertake seasonal migrations, spending summers feeding in high latitude, productive areas and winters in warmer, lower latitude breeding grounds (Kellogg 1929). North Pacific right whales spend their summers in the Ber- ing Sea and, to a lesser extent, the Gulf of Alaska, the Aleutian archipelago, and off Kodiak (Scarff 1986, Brownell et al. 2001, Clapham et al. 2004, Mellinger et al. 2004, Shelden et al. 2005, Wade et al. 2011a). Most current research effort has been focused within the area in the Southeastern Bering Sea where North Pacific right whales have been sighted most frequently (Wade et al. 2006, Munger et al. 2008). Over the years, however, a small number of sightings of single right whales have been Corresponding author (e-mail: asirovic@ucsd.edu).

Too Much Is Never Enough: The Cautionary Tale of Soviet Illegal Whaling

Despite being a signatory to the International Convention for the Regulation of Whaling in 1946, the U.S.S.R. conducted a 30-yr campaign of illegal whaling which arguably represents one of the greatest failures of management in the history of the industry. Here, using a variety of sources including published literature, formerly secret Soviet industry reports, and interviews with former biologists and whalers, we provide an overview of the history, scope, and economic origins of Soviet whaling and examine the domestic and international political context in which it was set. At various times from 1933 into the 1970’s, the U.S.S.R. operated a total of seven whaling factory fl eets and several shore whaling stations. We estimate that 534,119 whales were killed, of which 178,726 were not reported to the International Whaling Commission (IWC). In the Southern Hemisphere, the greatest impact of these catches was on humpback whales, Megaptera novaeangliae, where (mostly illegal) takes of more than 48,000 whales precipitated a population crash and closure of shore whaling stations in Australia and New Zealand. The Southern Hemisphere also saw large illegal catches of southern right whales, Eubalaena australis. In the North Pacifi c, the greatest impacts were on sperm whales, Physeter macrocephalus (where data on sex and length were routinely misreported together with falsifi ed total catches), as well as on the two already-small populations of right whales, Eubalaena japonica, across the North Pacifi c, and bowhead whales, Balaena mysticetus, in the Okhotsk Sea. Soviet whaling was driven by the state industrial planning system, which frequently set high production targets without regard to the ability of the resource to sustain the Introduction In this article, we trace the history and details of what might be called one of the 20th century’s more notorious environmental crimes: the global campaign of illegal whaling conducted by the U.S.S.R. between 1948 and 19721, a campaign that, together with the poorly managed “legal” whaling of other nations, devastated many whale populations. It is a story of the sprawling Soviet planning system’s obsession with attaining production goals despite limited and diminishing resources, and of the U.S.S.R.’s desire to do every1In 1972 an International Observer Scheme was introduced and large-scale Soviet unrestricted catches ceased, but some falsifi cations of catch data continued on at least some Soviet fl eets for a few more years (Mikhalev et al., 2009). thing bigger and better than other nations, especially those in the capitalist world. More than anything, this is a cautionary tale of the failure of other whaling nations and the International Whaling Commission (IWC) to react to mounting evidence of declining whale stocks, and to adequately monitor adherence to regulations and catch limits2 as set through international

Sightings of the western stock of North Pacific right whales (Eubalaena japonica) in the far southeast of the Kamchatka Peninsula

KEIKO SEKIGUCHI, Graduate School of Arts and Science, International Christian University, 3–10–2 Osawa, Mitaka City, Tokyo 181-8585, Japan; HIROJI ONISHI, Faculty of Fisheries Science, Hokkaido University, 3–1–1 Minato-cho, Hakodate City, Hokkaido 041-8611, Japan; HIROKO SASAKI, Graduate School of Fisheries Science, Hokkaido University, 3–1–1 Minato-cho, Hakodate City, Hokkaido 041-8611, Japan; SHOTA HABA, Graduate School of Bioresources, Mie University, 1577 Kurimamachiya-cho, Tsu City, Mie 514-8507, Japan; YUKA IWAHARA, Graduate School of Environmental Science, Hokkaido University, 3–1–1 Minato-cho, Hakodate City, Hokkaido 041-8611, Japan; DAISUKE MIZUGUCHI, Wildlife Research Center, Kyoto University, 2–24 Tanaka-Sekiden-cho, Kyoto City, Kyoto 606-8203, Japan; MAYUKO OTSUKI, Graduate School of Environmental Science, Hokkaido University, 3–1–1 Minato-cho, Hakodate City, Hokkaido 041-8611, Japan; DAISUKE SAIJO, School of Fisheries Science, Hokkaido University, 3–1–1 Minato-cho, Hakodate City, Hokkaido 0418611, Japan; BUNGO NISHIZAWA, Graduate School of Fisheries Science, Hokkaido University, 3–1–1 Minato-cho, Hakodate City, Hokkaido 041-8611, Japan; HIRONA MIZUNO and NAOKI HOSHI, School of Fisheries Science, Hokkaido University, 3–1–1 Minato-cho, Hakodate City, Hokkaido 041-8611, Japan; TAKEHIKO KAMITO, Department of Life Science, International Christian University, 3–10–2 Osawa, Mitaka City, Tokyo 181-8585, Japan.

Soviet catches of right whales Eubalaena japonica and bowhead whales Balaena mysticetus in the North Pacific Ocean and the Okhotsk Sea

Both bowhead Balaena mysticetus and North Pacific (NP) right whales Eubalaena japonica were reduced to low levels by historical whaling. Despite their protected status, it is known that the USSR illegally killed both species in the NP and Okhotsk Sea (OS). Here, we pro- vide revised Soviet catch totals, as well as other new information on the distribution and other details of these catches. Right whale catches were made from 1962 to 1968 in the eastern NP and in 1967 and 1968 in the OS. Our best estimate of total right whale catches is 661, consisting of 529 for the eastern NP (compared to the previously published figure of 372) and 152 for the OS (cf. a previous figure of 136). Catches were distributed in the Bering Sea (BS, 115), eastern Aleutian Islands (28), Gulf of Alaska (GOA, 366), OS (132), and other areas (20). Detailed information on catches of 112 right whales taken in May/June 1963 shows a broad distribution in offshore waters of the GOA, consistent with 19th century historical whaling records. Other major areas in which right whales were caught include south of Kodiak Island, western Bristol Bay (southeastern BS), and the central OS off eastern Sakhalin Island. The best estimate of bowhead whale catches in the OS in 1967 and 1968 is 145 animals, although this is contingent upon certain assumptions regard- ing species identity. Of these, 79 were killed in the Shantar Islands region and 66 in Shelikhov Bay. The catches of both species primarily involved large mature animals, thus greatly inhibiting recovery of the populations concerned.

Genetic analysis of right whales in the eastern North Pacific confirms severe extirpation risk

Genetic analysis of 49 biopsy samples from North Pacific right whales Eubalaena japonica in the eastern (48) and western (1) North Pacific revealed 24 individual whales with 7 mitochondrial haplotypes. Three pairs of large and small individuals were identified in the field; genotype analysis indicated that 2 of these could represent motheroffspring pairs; for the third small individual, no sampled female genetically qualified as a potential mother. In aggregate, the population appears to have lost some genetic diversity, though not to the degree of North Atlantic right whales E. glacialis, and males outnumber females 2:1. A comparison of the eastern Pacific samples to a single Russian sample suggested that the 2 populations are isolated to some degree. The effective population size for the eastern North Pacific was calculated to be 11.6 (95% CI: 2.9�75.0), based on the estimated linkage disequilibrium. These results further indicate that this population is at immediate risk of extirpation.

Public Willingness to Pay for Recovering and Downlisting Threatened and Endangered Marine Species

Nonmarket valuation research has produced economic value estimates for a variety of threatened, endangered, and rare species around the world. Although over 40 value estimates exist, it is often difficult to compare values from different studies due to variations in study design, implementation, and modeling specifications. We conducted a stated-preference choice experiment to estimate the value of recovering or downlisting 8 threatened and endangered marine species in the United States: loggerhead sea turtle (Caretta caretta), leatherback sea turtle (Dermochelys coriacea), North Atlantic right whale (Eubalaena glacialis), North Pacific right whale (Eubalaena japonica), upper Willamette River Chinook salmon (Oncorhynchus tshawytscha), Puget Sound Chinook salmon (Oncorhynchus tshawytscha), Hawaiian monk seals (Monachus schauinslandi), and smalltooth sawfish (Pristis pectinata). In May 2009, we surveyed a random sample of U.S. households. We collected data from 8476 households and estimated willingness to pay for recovering and downlisting the 8 species from these data. Respondents were willing to pay for recovering and downlisting threatened and endangered marine taxa. Willingness-to-pay values ranged from $40/household for recovering Puget Sound Chinook salmon to $73/household for recovering the North Pacific right whale. Statistical comparisons among willingness-to-pay values suggest that some taxa are more economically valuable than others, which suggests that the U.S. public's willingness to pay for recovery may vary by species.

Insights into North Pacific right whale Eubalaena japonica habitat from historic whaling records

ESR Endangered Species Research Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsSpecials ESR 15:223-239 (2011) - DOI: https://doi.org/10.3354/esr00381 Theme Section: Beyond marine mammal habitat modeling: applications for ecology and conservation Insights into North Pacific right whale Eubalaena japonica habitat from historic whaling records Edward James Gregr* SciTech Environmental Consulting, 2136 Napier Street, Vancouver, British Columbia V5L 2N9, Canada *Email: ed@scitechconsulting.com ABSTRACT: Whaling records from the mid-1800s provide the largest set of observations with which to conduct a basin-scale analysis of potential North Pacific right whale Eubalaena japonica habitat. Since these data lack the concurrent oceanographic data necessary to investigate the species’ habitat characteristics I used ocean climate from a 20th century circulation model to create a suitable set of habitat predictors. My goals were to (1) identify regions of suitable habitat and (2) investigate the processes underlying the species–habitat relationship by (3) examining model performance at different spatial and temporal scales. The results show 2 non-overlapping habitat regions in the subarctic North Pacific, supporting the notion of 2 distinct subpopulations. The analysis also implicates surface temperature and temperature variability as strong indicators of potential right whale habitat. Tests of model performance at different scales strongly suggest that at the basin-scale, right whales use regions of cold water with low inter-annual variability and high within-season variability (i.e. areas where high frontal activity occurs predictably from year to year). The significance of these indicators decreased at the regional scale emphasising the coupling of scale and process, and thus the need for different predictors at different scales. Comparisons of models built using different subsets of the dependent data showed how hypotheses can be tested and potential biases in observational data can be explored. Analyses of rare species’ habitat such as this can provide guidance for more directed survey efforts and help identify areas and processes of potential biological importance. KEY WORDS: Habitat suitability model · Pelagic habitat · Concentration features · Critical habitat · Habitat processes · Ecological niche · Presence-only · Maximum entropy Full text in pdf format PreviousNextCite this article as: Gregr EJ (2011) Insights into North Pacific right whale Eubalaena japonica habitat from historic whaling records. Endang Species Res 15:223-239. https://doi.org/10.3354/esr00381 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in ESR Vol. 15, No. 3. Online publication date: December 12, 2011 Print ISSN: 1863-5407; Online ISSN: 1613-4796 Copyright © 2011 Inter-Research.

First high‐ to low‐latitude match of an eastern North Pacific right whale (Eubalaena japonica)

First high‐ to low‐latitude match of an eastern North Pacific right whale (<i>Eubalaena japonica</i>)

New call type produced by the North Pacific right whale, Eubalaena japonica

The North Pacific right whale, (NPRW), is one of the most endangered baleen whales in the world and has been the focus of intensive population monitoring studies. In 2010 during transit through the Bering Sea right whale critical habitat (BSCH), near-24-h acoustic monitoring was conducted using DiFAR-capable sonobuoys. A new call pattern was detected during a focal follow of a NPRW, consisting of a series of pulses with a fundamental frequency at 110 Hz and peak energy at 640 Hz, ending in a 250–150 Hz downsweep. This call pattern was repeated multiple times and detected in the presence of gunshot and upsweep calls. Directional bearings to the call were a perfect match to those of the gunshot call. Although humpback whales were present, bearings to the humpback vocalizations were in the opposite direction (200 deg difference). The only other species detected visually or acoustically in the area were fin whales. This same pattern was detected in October and November on a 2009 long-term recorder in the BSCH, also in the presence of gunshot and upsweep calls. Because directional information from the sonobuoys during the focal follow exactly matched those from the gunshot call, we attribute this call pattern to the NPRW.

North Pacific right whale up-call source levels and propagation distance on the southeastern Bering Sea shelf

Call source levels, transmission loss, and ambient noise levels were estimated for North Pacific right whale (Eubalaena japonica) up-calls recorded in the southeastern Bering Sea in autumn of 2000 and 2001. Distances to calling animals, needed to estimate source levels, were based on two independent techniques: (1) arrival-time differences on three or more hydrophones and (2) shallow-water dispersion of normal modes on a single receiver. Average root-mean-square (rms) call source levels estimated by the two techniques were 178 and 176 dB re 1 μPa at 1 m, respectively, over the up-call frequency band, which was determined per call and averaged 90 to 170 Hz. Peak-to-peak source levels were 14 to 22 dB greater than rms levels. Transmission loss was approximately 15∗log(10)(range), intermediate between cylindrical and spherical spreading. Ambient ocean noise within the up-call band varied from 72 to 91 dB re 1 μPa(2)/Hz. Under average noise conditions, call spectrograms were detectable for whales at distances up to 100 km, but propagation and detection distance may vary depending on environmental parameters and anthropogenic noise. Obtaining distances to animals and acoustic detection range is a step toward using long-term passive acoustic recordings to estimate abundance for this critically endangered whale population.

Estimating North Pacific right whale Eubalaena japonica density using passive acoustic cue counting

We present a method for estimating animal density from fixed passive acoustic detec- tors, and illustrate it by estimating the density of North Pacific right whales Eubalaena japonica in the areas surrounding 3 hydrophones deployed in the southeastern Bering Sea in 2001 to 2002 and 2005 to 2006. Input data were the distances to detected right whale calls, estimated using a normal mode sound propagation model, and call production rate, estimated from encounters by survey vessels with right whale groups. Given the scarcity of information about this highly endangered species, we also extrapolate our results to provide a tentative estimate of the total population size in shelf waters of the eastern Bering Sea. This gives a point estimate of 25 animals (CV 29.1%; 95% confidence interval 13-47), which agrees well with what little is known for this species. We discuss the assumptions underlying the method. Obtaining more reliable values requires a larger sample of randomly located hydrophones, together with improved estimates of call rate.

Rare detections of North Pacific right whales in the Gulf of Alaska, with observations of their potential prey

The North Pacific right whale Eubalaena japonica was heavily exploited throughout the Gulf of Alaska by both historical whaling and 1960s illegal Soviet catches. It is now extremely rare in this region (2 sightings between 1966 and 2003 and passive acoustic detections on 6 days out of 80 months of recordings at 7 locations). From 2004 to 2006, 4 sightings of right whales occurred in the Barnabus Trough region on Albatross Bank, south of Kodiak Island, Alaska, USA. Sightings of right whales occurred at locations within the trough with the highest density of zooplankton, as measured by active acoustic backscatter. Net trawls through a high-density demersal layer (~150 to 175 m) revealed large numbers of euphausiids and oil-rich C5-stage copepods. Photo-identification and genotyping of 2 whales failed to reveal a match to Bering Sea right whales. Fecal hormone metabo- lite analysis from 1 whale estimated levels consistent with an immature male, indicating either recent reproduction in the Gulf of Alaska or movements between the Bering Sea and the Gulf of Alaska. Large numbers of historic catches of right whales occurred in pelagic waters of the Gulf of Alaska, but there have been few recent detections in deep water. Given that there is no other location in the Gulf of Alaska where right whales have been repeatedly seen post-exploitation, the Barnabus Trough/Albatross Bank area represents important habitat for the relict population of North Pacific right whales in the Gulf of Alaska, and a portion of this area was designated as critical habitat under the US Endangered Species Act in 2006.