The feasibility of assessing the diets of minke whale (<Emphasis Type="Italic">Balaenoptera acutorostrata</Emphasis>) in the East Sea through fatty acid composition in blubber and stable isotopic ratio of skin

To track the diet of minke whale (Balaenoptera acutorostrata) in the East Sea (Japan Sea), a conjoint analysis of fatty acids and C and N stable isotopes was performed on blubber and skin from the whale and its potential prey. The total lipid content in the blubber of minke whales ranged from 37.9% to 82.7% of wet mass (mean ± SD, 63.1 ± 17.2%), with triacylglycerols being the dominant lipids (96.9%–99.2% of total lipids). The lipid and fatty acid (FA) contents were systematically stratified throughout the depth of the blubber layers; contents of the dominant monounsaturated FAs (MUFAs), including 18:1ω9 and 16:1ω7, increased from the innermost layer to the outermost layer, whereas contents of saturated FAs (SFAs) and polyunsaturated FAs (PUFAs) were higher in the innermost layer than in the outermost layer. This stratification is related to the different physiological roles of the blubber layers; e.g., thermoregulation, streaming, and buoyancy. A comparison of the FA compositions of the innermost layer of minke whales with those of potential prey indicates that FA compositions in the whales are similar to those of Pacific herring. In addition, stable isotope ratios (δ¹³C and δ¹⁵N) suggest that minke whale and Pacific herring have the same or similar diets. Therefore, the diets of minke whale from the East Sea (Japan Sea) could be inferred from information on the diet of the Pacific herring, although FA compositions and stable isotope ratios for Pacific herring would not exactly reflect the whale’s diet. Although the very limited number of samples was used in this study, our preliminary findings are very promising to help understand the feeding ecology of minke whales in the East Sea (Japan Sea).     

Predictive habitat modelling of humpback (Megaptera novaeangliae) and Antarctic minke (Balaenoptera bonaerensis) whales in the Southern Ocean as a planning tool for seismic surveys

Seismic surveys are frequently a matter of concern regarding their potentially negative impacts on marine mammals. In the Southern Ocean, which provides a critical habitat for several endangered cetacean species, seismic research activities are undertaken at a circumpolar scale. In order to minimize impacts of these surveys, pre-cruise planning requires detailed, spatio-temporally resolved knowledge on the likelihood of encountering these species in the survey area. In this publication we present predictive habitat modelling as a potential tool to support decisions for survey planning. We associated opportunistic sightings (2005–2011) of humpback (Megaptera novaeangliae, N=93) and Antarctic minke whales (Balaenoptera bonaerensis, N=139) with a range of static and dynamic environmental variables. A maximum entropy algorithm (Maxent) was used to develop habitat models and to calculate daily basinwide/circumpolar prediction maps to evaluate how species-specific habitat conditions evolved throughout the spring and summer months. For both species, prediction maps revealed considerable changes in habitat suitability throughout the season. Suitable humpback whale habitat occurred predominantly in ice-free areas, expanding southwards with the retreating sea ice edge, whereas suitable Antarctic minke whale habitat was consistently predicted within sea ice covered areas. Daily, large-scale prediction maps provide a valuable tool to design layout and timing of seismic surveys as they allow the identification and consideration of potential spatio-temporal hotspots to minimize potential impacts of seismic surveys on Antarctic cetacean species.     

Distribution and seasonal abundance of large cetaceans in the Durban whaling grounds off KwaZulu-Natal,South Africa, 1972–1975

Daily charts of the aerial search effort (432 206 nautical miles) of the Union Whaling Company and 1 099 sightings of 10 497 whales were available from 628 flights off Durban between 1972 and 1975. Densities of whales were analysed by month and water depth distribution over the four-year period. Low observed densities of blue Balaenoptera musculus, right Eubalaena australis, sei B. borealis and humpback Megaptera novaeangliae whales most likely resulted from earlier whaling pressure. Seasonality of blue, sei and humpback whales was bimodal, indicative of winter migrations to the north of the Durban whaling grounds, whereas the unimodal seasonality of fin whales B. physalus and minke whales B. bonaerensis or B. acutorostrata suggest the offshore region as the northern terminus of their migrations. Sperm whales Physeter macrocephalus migrate northwards offshore of the KwaZulu-Natal coast in autumn/early winter and southwards in late winter/spring, with larger males migrating later than the smaller males and females. Killer whale Orcinus orca presence was coincident with that of offshore minke whales and the southward migrations of other baleen whales, whereas densities of animals deemed as bottlenose whale Hyperoodon planifrons suggest strong early and late summer seasonal abundance in the offshore region. Such extensive surveys offshore of the KwaZulu-Natal coast are unlikely to be repeated; hence, data-extraction of whaling records provides a valuable source of seasonal and distributional information for marine management.     

Spatiotemporal modelling for policy analysis: Application to sustainable management of whale-watching activities

Anticipating the impacts of a new policy before implementation on a complex social–ecological system is a challenging task for managers and policymakers. This paper reports on the development and use of an agent-based model (ABM) dedicated to support marine park managers in their effort to devise policies to sustainably manage whale-watching activities. The ABM, called the Marine Mammal and Maritime Traffic Simulator (3MTSim), represents the spatiotemporal dynamics of marine mammals and navigation activities in and around the Saguenay–St. Lawrence Marine Park in Canada. In the context of updating the current regulations on whale-watching in the Marine Park, 3MTSim was run to evaluate the merits of a proposed set of rules compared to the current regulations. To do so, a set of variables related to policies’ impacts on the three spheres of sustainable development, namely the impact on whales (Environment), on whale-watching companies (Economy), and tourist experience (Society) was analysed. 3MTSim's simulations highlighted that the proposed rules are expected to improve the situation regarding whale conservation and tourist experience with only marginal impact on the whale-watching industry. In the proposed regulations, one rule is expected to be very influential on whale-watching activities. This rule limits to 10 the number of whale-watching boats allowed to stand within 926 m of any boat in observation mode. Assuming efficient law enforcement, 3MTSim predicts a significant decrease in overall boat concentration around whales in the Marine Park, which is one of the management objectives benefiting both whales and tourists. Interestingly, 3MTSim reveals that this rule could indirectly force some boats to observe second-choice whales present in higher abundance rather than some more attractive species scarcer in the region. This highlights the following management tradeoffs: Reducing boat exposure for the humpback whale and endangered blue whale is likely to increase it for the more abundant fin whale listed as of special concern (Canada's Species at Risk Act) and minke whale. This work demonstrates the utility of ABMs to support policy analysis in the context of sustainable management in a Marine Park. ABMs developed in close relationship with end-users are unarguably a tool of choice to manage complex social–ecological systems since they provide insight into phenomena hard or impossible to measure in the real system. Despite the labour intensive nature of their implementation, this investment is worth the effort.     

Ecological aspects of fin whale and humpback whale distribution during summer in the Norwegian Sea

The Norwegian Sea is a migration and feeding ground for fin whales (Balaenoptera physalus) and humpback whales (Megaptera novaeangliae) in summer. During the last decade, significant structural changes in the prey community, including northerly expansion and movement in the distribution of pelagic fish species, have been reported from this ecosystem. However, little information on whale feeding ecology exists in the Norwegian Sea and surrounding waters. A total of 59 fin whales and 48 humpback whales were sighted during 864 h of observation over an observation distance of about 8200 nmi (15,200 km) in the Norwegian Sea from 15 July to 6 August 2006 and 2007. The fin whale group size, as mean (±SD), varied between one and five individuals (2.1 ± 1.2 ind.) and humpback whale group size varied between one and six individuals (2.5 ± 1.7 ind.). Fin‐ and humpback whales were observed mainly in the northern part of the study area, and were only found correlated with the presence of macro‐zooplankton in cold Arctic water. Humpback whales were not correlated with the occurrence of adult Norwegian spring‐spawning herring (Clupea harengus) except for the northernmost areas. Despite changes in the whale prey communities in the Norwegian Sea, no apparent changes in fin‐ or humpback whale distribution pattern could be found in our study compared to their observed summer distribution 10–15 years ago.     

Using trace elements in skin to discriminate the populations of minke whales in southern hemisphere

Concentrations of 12 trace elements (V, Cr, Mn, Cu, Zn, Se, Rb, Sr, Cd, Cs, Ba, and Hg) were determined in liver and skin tissues of minke whales from various regions within the Antarctic Ocean. Cd concentrations in livers of southern minke whale were apparently higher than those in cetaceans from other regions, while Hg concentrations were lower. There were significant positive correlations between body length and concentrations of Cd and Hg in the liver. The concentrations of all trace elements in the skin were lower than those in other cetaceans reported previously. Significant positive correlations between liver and skin were found for Cr, Mn, Cu, Zn, Rb, Cd, and Cs, implying that the concentrations of these trace elements in the skin reflect those of internal organs. Large interannual variation of the accumulation pattern of trace elements in the skin was observed for the southern minke whales from Area V. There were significant differences in the skin element concentrations among Areas III, IV, and V, especially for males. Also, discriminant analysis between geographically two different groups collected during 1995/1996 austral summer season, based on the concentrations of trace elements in the skin, allowed for a correct classification of 90% of these minke whales. These results suggest that measurement of trace elements in skin samples could provide valuable information on the status of contamination and possible geographic differences in the accumulation levels in southern minke whales.     

A digital acoustic recording tag for measuring the response of wild marine mammals to sound

Definitive studies on the response of marine mammals to anthropogenic sound are hampered by the short surface time and deep-diving lifestyle of many species. A novel archival tag, called the DTAG, has been developed to monitor the behavior of marine mammals, and their response to sound, continuously throughout the dive cycle. The tag contains a large array of solid-state memory and records continuously from a built-in hydrophone and suite of sensors. The sensors sample the orientation of the animal in three dimensions with sufficient speed and resolution to capture individual fluke strokes. Audio and sensor recording is synchronous so the relative timing of sounds and motion can be determined precisely. The DTAG has been attached to more than 30 northern right whales (Eubalaena glacialis) and 20 sperm whales (Physeter macrocephalus) with recording duration of up to 12 h per deployment. Several deployments have included sound playbacks to the tagged whale and a transient response to at least one playback is evident in the tag data.     

鲸豚声信号实时采集与分析系统

本文设计了一套基于FPGA的鲸豚声信号实时数据采集与分析系统,在采集存储水族馆内声信号的同时,应用改进的HHT算法处理鲸豚叫声中的click信号,实现实时的甄别瓶鼻海豚和白鲸功能,可用于针对大型哺乳动物的远洋实时跟踪科考。     

The discovery of a natural whale fall in the Antarctic deep sea

Large cetacean carcasses at the deep-sea floor, known as ‘whale falls’, provide a resource for generalist-scavenging species, chemosynthetic fauna related to those from hydrothermal vents and cold seeps, and remarkable bone-specialist species such as Osedax worms. Here we report the serendipitous discovery of a late-stage natural whale fall at a depth of 1444 m in the South Sandwich Arc. This discovery represents the first natural whale fall to be encountered in the Southern Ocean, where cetaceans are abundant. The skeleton was situated within a seafloor caldera, in close proximity (<250 m) to active hydrothermal vents. We used a DNA barcoding approach to identify the skeleton as that of an Antarctic minke whale (Balaenoptera bonaerensis). The carcass was in an advanced state of decomposition, and its exposed bones were occupied by a diverse assemblage of fauna including nine undescribed species. These bone fauna included an undescribed species of Lepetodrilus limpet that was also present at the nearby hydrothermal vents, suggesting the use of whale-fall habitats as stepping stones between chemosynthetic ecosystems. Using Remotely Operated Vehicle (ROV) videography, we have quantified the composition and abundance of fauna on the whale bones, and tested a hypothesis that varying concentrations of lipids in the bones of whales may influence the microdistribution of sulfophilic whale-fall fauna. Our data supported the hypothesis that more lipid-rich bones support a greater abundance of sulfophilic bacterial mats, which are also correlated with the abundance of grazing limpets (Pyropelta sp.). The abundance of Osedax sp. on bones however, showed a negative correlation with the bacterial-mat percentage cover, and hence greatest abundance on bones predicted to have lowest lipid content.     

Whale watching, the Buenos Aires Group and the politics of the International Whaling Commission

Whale watching is now reputed to be a $2 billion a year industry. This industry has the potential to impact the politics of whaling, specifically the moratorium on all commercial whaling in three ways: by creating political and economic counterweights to whalers, by countering claims about who may legitimately manage whales and to what end and by transforming views about whales and whaling both within whaling states and beyond. This article examines whale watching in Latin America and the Caribbean and the alliance of Latin American and Caribbean members of the International Whaling Commission (IWC) known as the Buenos Aires Group (BAG). The BAG group has emerged as coherent group opposing the ending of the moratorium and championing the views of whale watchers. The article finds that whale watching creates a politically important interest group in an area lacking whaling operations; it argues that these regional opponents of whaling provide a counter weight to charges that opposition to whaling is exclusively the providence of rich, urban citizens of developed countries and draw upon politically powerful frames in justifying their opposition to the lifting of the moratorium. Finally, it finds limited evidence that whale-watching is associated with a rise in general concern for marine mammals in the region. There remains the question, however, of what the future of whale watching in the region will be over the longer term.     

Prey preferences among the community of deep-diving odontocetes from the Bay of Biscay, Northeast Atlantic

Long-finned pilot whales (Globicephala melas), Risso's dolphins (Grampus griseus), melon-headed whales (Peponocephala electra), Cuvier's beaked whales (Ziphius cavirostris), Sowerby's beaked whales (Mesoplodon bidens), northern bottlenose whales (Hyperoodon ampullatus), sperm whales (Physeter macrocephalus), dwarf sperm whales (Kogia sima) and pygmy sperm whales (Kogia breviceps) make up the large community of deep-diving odontocetes occurring off the Bay of Biscay, northeast Atlantic. The ecology of these toothed cetaceans is poorly documented worldwide. The present study described their prey preferences from stomach content analysis and showed resource partitioning within the assemblage. The majority of the species appeared to be mostly teutophageous. Fish was an important food source only for the Sowerby's beaked whale and, to a lesser extent, for the long-finned pilot whale. In terms of foraging habitats inferred from prey composition, either pelagic oceanic or demersal neritic habitats were exploited by toothed whales in the Bay of Biscay, with only the long-finned pilot whale foraging in the two habitats. Finally, with more than 14,000 identified cephalopods from 39 species, the present study highlighted also the poorly known deep-sea cephalopod community off the Bay of Biscay using top predators as biological samplers.     

Transfer of60Co from midwater squid to sperm whales

Sperm whales are notable squid-eaters. They feed mainly on medium to large-sized cephalopods at midwater levels and defecate near the surface. This suggests the existence of an upward transport of⁶⁰Co by sperm whales from the mesopelagic zone (150–1,200 m). To elucidate this squid-whale route for this artificial radionuclide,⁶⁰Co content was determined in squid and in predator whales captured by commercial whaling. In the Cephalopoda livers⁶⁰Co levels of 30–500 mBq kg^–1 wet were found and in the viscera of Odontoceti (toothed whales) 15–40 mBq kg^–1 wet. About 0.3% of⁸⁰Co ingested was estimated to be retained in a 23-year-old male sperm whale. In the livers of Bryde's whales,⁶⁰Co levels of 40–80 mBq kg^–1 wet were detected, but not in euphausiids and sardines, their possible prey. The level of Co in sperm whales was nearly the same as in Bryde's whales. Specific radioactivity⁶⁰Co/⁵⁹Co in mBq µg^–1 was several times higher in sperm whale (1.1–1.6) than in cephalopods (0.19–0.77). Eating prey with a high content of⁶⁰Co in the 1960's may have contributed to the present body burden in sperm whales with a long-life span. However, the origin of⁶⁰Co in Bryde's whales is unknown.     

Acoustic detections of blue whale (Balaenoptera musculus) and fin whale (B. physalus) sounds during a SURTASS LFA exercise

Acoustic data collected on the R/V Cory Chouest in February and March 1996 during an active operation of the U.S. Navy's surveillance-towed-array-sensor-system low-frequency-active (LFA) sonar were analyzed for blue whale (Balaenoptera musculus) and fin whale (B. physalus) sounds. Operational monitoring and mitigation protocols were implemented throughout the exercise to reduce the chances of an acoustic impact on marine mammals and sea turtles. The operational schedule did not include intentional "control" periods without transmissions but did include periods when the LFA sonar was not operating for other reasons (e.g., repairs). There were insufficient detections of blue whales for further analysis. Fin whale acoustic detection probabilities were calculated from the postprocessed data. A local-linear-regression analysis was used to compare fin whale detection probabilities from 2065 11-min intervals under conditions when the LFA sonar was and was not transmitting. There was an indication of a slightly higher probability of detecting fin whale sounds during periods when there were no LFA transmissions than during periods with transmissions. This may be the result of the following: 1) Reduced vocal activity by whales in response to LFA transmissions; 2) the effect of the mitigation protocols; or 3) some combination of 1) and 2). The data presently available do not allow one to distinguish definitively between these explanations, mainly because there were not enough data recorded for periods without LFA transmissions.     

Intra- and inter-species differences in persistent organic contaminants in the blubber of blue whales and humpback whales from the Gulf of St. Lawrence, Canada

Biopsy samples of blubber from adult male and female blue whales, and from female and young-of-the-year humpback whales were collected during the summers of 1992-1999 in the Gulf of St. Lawrence, Canada. In blue whales, concentrations of 25 PCB congeners, DDT and metabolites and several other organochlorine compounds were present at higher concentrations in the blubber of males relative to females; reflecting maternal transfer of these persistent contaminants from females into young. Sex-related differences in concentrations were not observed with less persistent contaminants, such as HCHs. In humpback whale samples, there were no significant differences in the concentrations of PCBs and organochlorine compounds in the blubber of females and calves. These data indicate that calves quickly bioaccumulate contaminants by transplacental and lactational routes to concentrations that are in equilibrium with females. In comparisons between contaminant concentrations and patterns in the blubber of female blue and humpback whales, there were no significant differences in concentrations, but the proportions of some PCB congeners, HCH isomers, and DDT and its metabolites were different in the two baleen whale species. These may reflect differences in the diet of the two species, since fish comprise a large part of the diet of humpback whales and blue whales feed exclusively on euphausiid crustaceans (i.e. krill).     

Evidence that whales (Balaenoptera borealis) visit drifting fish aggregating devices: do their presence affect the processes underlying fish aggregation?

Evidence of the presence of a group of sei whales (Balaenoptera borealis) detected around drifting fish aggregating devices (FADs) was provided by omnidirectional multi‐beam sonar during a survey off the Seychelles (Indian Ocean). The short visit by the sei whales produced a significant change in the behaviour of the fish assemblage associated with the FAD. There was first a significant increase in fish density when the whales approached the FAD, then a marked decrease after the whales had moved away from the FAD. Furthermore, the fish density was still low, 3 h after the whales had left the FAD. We assume that the presence and behaviour of the sei whales led some of the fish initially associated with the FAD to move away from it. There has been a considerable increase in the use of drifting artificial FADs in the Indian Ocean in recent decades. The frequency of cetacean visits to drifting FADs in the Indian Ocean is unknown, but they may have a major impact on assemblages of pelagic fish species around FADs. The effect of marine mammals on FAD‐associated fish could be relevant to the ecological trap theory (FAD acting as a trap for their associated fish) because of their impact on the dynamics of fish aggregation processes, through commensalism and/or predator–prey interactions.     

Searching for novel CYP members using cDNA library from a minke whale liver

The contaminant-induced cytochrome P450 (CYP) members in minke whale (Balaenoptera acutorostrata) can be potential biomarkers of the contaminant exposure and toxic effects. In this study, we constructed a cDNA library from the liver of minke whale from the North Pacific, and further screened a total of 6930 clones randomly selected in the library for the isolation of cDNA clones encoding novel members of CYP superfamily. The screening revealed the isolation of six novel CYP cDNA clones that are classified into CYP1A, CYP2C, CYP2E, CYP3A, CYP4, and CYP4A subfamilies. The BLAST homology search using the partial cDNA fragments of four CYP subfamilies (CYP1A, CYP2C, CYP2E and CYP4A) demonstrated that the minke whale CYPs were most closely related to pig CYPs (81-91%). Identification of multiple CYP genes in marine mammal species such as minke whale will provide new insights into the metabolic or toxicological functions of individual CYP members.     

Whale interactions with Alaskan sablefish and Pacific halibut fisheries: Surveying fishermen perception,changing fishing practices and mitigation

Whale depredation occurs when whales steal fish, damage fish or damage fishing gear. In Alaska, killer whales (Orcinus orca) and sperm whales (Physeter macrocephalus) primarily depredate on demersal sablefish (Anoplopoma fimbria) and Pacific halibut (Hippoglossus stenolepis) longline fisheries. Quantitative data on whale depredation in Alaska is limited due to low fishery observer coverage and minimal depredation evidence left on longline fishing gear. This study utilized semidirected interviews (n=70) and written questionnaires (n=95) with longline fishermen to examine: (1) perceptions and experiences of whale–fishery interactions in Alaska, (2) effects of depredation on fishing practices, and (3) potential depredation mitigation measures. Eighty-seven percent of fishermen surveyed agreed that whale depredation became worse between 1990 and 2010. Respondents reported changing their fishing practices in response to depredating whales in several ways, including: traveling up to 50 nautical miles and ceasing hauling operations up to 24 h until the whales left the fishing grounds. Respondents fishing in western Alaska, primarily encountering killer whales, were forced to wait longer and travel greater distances than fishermen operating in central and southeast Alaska, regions more affected by sperm whales. Deterrent research, gear modifications and real-time tracking of depredating whales were solutions favored by study participants. Survey respondent answers varied based on areas fished, quota owned, years involved in the fishery and vessel size. This study presents the first statewide evaluation of fishermen's perception and knowledge of whale interactions with the Alaskan longline fleet and is a critical step toward developing baseline data and feasible depredation mitigation strategies.     

Acoustic behaviour of southern right whales in relation to numbers of whales present in Walker Bay,South Africa

Estimating numbers of whales present in an area from recorded call rates could be a useful conservation tool. We recorded southern right whale Eubalaena australis vocalisations and presence in Walker Bay on the south coast of South Africa. In all, 45 sessions with synchronous acoustic and visual data were analysed to determine call rates directly (overall call rate, OCR) and in relation to the number of whales sighted (call rate per whale, CPW) and number of groups sighted (call rate per group, CPG). The OCRs were examined in the presence of varying numbers of whales, using a log-linear model to investigate the dependence of the call rate on whale density. The number of whales present exerted a strong quadratic effect on the OCR, which peaked at around 15 whales and decreased to a low rate as whale presence approached a maximum, for all calls combined and for four of their constituent 13 call types: a quadratic trend was present to varying degrees among the remaining call types. Both quadratic and linear trends were absent when OCR was assessed against number of groups present, possibly because group size increased with increasing density of whales. A linear regression on the CPW and CPG suggested that there was a negative inverse relationship with the number of whales and groups present respectively. These findings are important in that, while they preclude the estimation of absolute numbers from call rates, they imply that, under the conditions prevailing in Walker Bay, southern right whales were aware of the presence, arrival and departure of other animals in their vicinity and adjusted their vocal behaviour accordingly.     

Use of chemical tracers in assessing the diet and foraging regions of eastern North Pacific killer whales

Top predators in the marine environment integrate chemical signals acquired from their prey that reflect both the species consumed and the regions from which the prey were taken. These chemical tracers-stable isotope ratios of carbon and nitrogen; persistent organic pollutant (POP) concentrations, patterns and ratios; and fatty acid profiles-were measured in blubber biopsy samples from North Pacific killer whales (Orcinus orca) (n=84) and were used to provide further insight into their diet, particularly for the offshore group, about which little dietary information is available. The offshore killer whales were shown to consume prey species that were distinctly different from those of sympatric resident and transient killer whales. In addition, it was confirmed that the offshores forage as far south as California. Thus, these results provide evidence that the offshores belong to a third killer whale ecotype. Resident killer whale populations showed a gradient in stable isotope profiles from west (central Aleutians) to east (Gulf of Alaska) that, in part, can be attributed to a shift from off-shelf to continental shelf-based prey. Finally, stable isotope ratio results, supported by field observations, showed that the diet in spring and summer of eastern Aleutian Island transient killer whales is apparently not composed exclusively of Steller sea lions.