Rate of energy depletion and overwintering mortality of juvenile walleye pollock in cold water

The winter energy deficit and mortality of juvenile walleye pollock at extremely cold temperature were examined by field observations and laboratory experiments. In the Doto area, along the northern coast of Japan, juvenile walleye pollock resided on the continental shelf despite extremely cold temperatures (mean 0·4° C) during the latter half of winter (March to April). Measurements of the rate of energy depletion (equivalent to the routine metabolic rate) revealed that juvenile walleye pollock consumed 37% less energy at 0·5° C than at 2·0° C, suggesting an energetic benefit of residence in cold water (<1·0° C) over the shelf during winter. Prior to the starvation experiments, temperatures and ration level in the holding tanks were adjusted to create two different body condition groups of fish. Under the thermal condition of the latter half of winter (0·5° C), fish with a mean condition factor of 0·6 and 0·5 suffered 19·1 and 74·5% mortality, respectively, at the end of the experiments (after 56 days). The residual analysis of total body energy demonstrated that the cause of mortality was mainly associated with the depletion of energy reserves. When a logistic regression model for mortality derived from the experiments was applied to wild fish collected in March, the estimated overwintering mortality in 2004 and 2005 was 25·4 and <2·3%, respectively, assuming no feeding during the winter. Considering that juvenile walleye pollock feed during winter as shown in previous studies, intense overwintering mortality induced by energy depletion is improbable during the latter half of winter in the Doto area.     

Winter energy allocation and deficit of juvenile walleye pollock <Emphasis Type="Italic">Theragra chalcogramma</Emphasis> in the Doto area,northern Japan

Seasonal energy allocation and deficits of marine juvenile fishes have considerable effects on their survival. To explore the winter survival mechanism of marine fishes with low lipid reserves in their early life, juvenile walleye pollock Theragra chalcogramma were collected along the continental shelf of northern Japan over a 2-year period, and energy allocation and deficit patterns were compared between wild and laboratory-starved fish. Contrary to expectations, wild fish generally continued to accumulate protein mass and concurrently tended to reduce lipid mass from late autumn through winter. The most plausible explanation for the continuous structural growth is that juvenile pollock give priority to reducing mortality risk from size-selective predators under quasi-prey-limited conditions. Exceptionally, inshore small fish reduced both constituents during a winter. The inshore fish consumed 2.5 times more lipid energy than protein energy in November–December, but protein was more important than lipids as a source of energy in December–January and in February–March. However, dependence upon protein reserves was lower for the wild fish than for the laboratory-starved fish, suggesting milder nutritional stress of the wild fish than that observed in the starvation experiment. Moreover, the lipid contents of mortalities in the starvation experiment were mostly <1%, whereas few wild fish had such lipid contents in the field. These results suggest that juvenile pollock are able to avoid both starvation and predation by accumulating protein reserves.     

Horizontal and vertical distribution and demography of euphausiids in the Ross Sea and its adjacent waters in 2004/2005

The horizontal and vertical distribution and population structure of euphausiids in the Ross Sea and its adjacent waters were investigated during the summers of 2004/2005 using stratified towed samples. Nine species of euphausiids occurred in the survey area. Among them, Euphausia triacantha was dominant in biomass north of the southern boundary of the Antarctic circumpolar current (SB). Thysanoessa spp. was widely distributed north of the continental slope, while E. superba was distributed from the SB to the slope, where it showed the highest biomass. Juvenile E. superba was distributed offshore near the SB and remained at the surface, but gravid females were dominant in the slope and mainly occurred in the middle layers (400–600 m). Adult and juvenile E. crystallorophias were found at 200–300 m in the colder water of the continental shelf. In general, the peak biomass of euphausiids was found in the mid layers of the Ross Sea area. The life span and the number of spawns for major species are also discussed.     

Juvenile sockeye salmon distribution, size, condition and diet during years with warm and cool spring sea temperatures along the eastern Bering Sea shelf

Interannual variations in distribution, size, indices of feeding and condition of juvenile Bristol Bay sockeye salmon Oncorhynchus nerka collected in August to September (2000–2003) during Bering–Aleutian Salmon International Surveys were examined to test possible mechanisms influencing their early marine growth and survival. Juvenile sockeye salmon were mainly distributed within the southern region of the eastern Bering Sea, south of 57°0' N during 2000 and 2001 and farther offshore, south of 58°0' N during 2002 and 2003. In general, juvenile sockeye salmon were significantly larger ( P < 0·05) and had significantly higher indices of condition ( P < 0·05) during 2002 and 2003 than during 2000 and 2001. The feeding index was generally higher for age 1.0 year sockeye salmon than age 2.0 year during all years. Among-year comparisons suggested that Pacific sand lance Ammodytes hexapterus were important components of the juvenile sockeye salmon diet during 2000 and 2001 (20 to 50% of the mean wet mass) and age 0 year walleye pollock Theragra chalcogramma were important components during 2002 and 2003 (50 to 60% of the mean wet mass). Warmer sea temperatures during spring and summer of 2002 and 2003 probably increased productivity on the eastern Bering Sea shelf, enhancing juvenile sockeye salmon growth.     

Prey selection by age-0 walleye pollock, Theragra chalcogramma, in nearshore waters of the Gulf of Alaska

Juvenile walleye pollock, Theragra chalcogramma, is the dominant forage fish on the continental shelf of the Gulf of Alaska, yet little is known about the feeding habits of this important interval of pollock life history. The taxonomic composition and size of prey found in the stomachs of age-0 juveniles collected at three nearshore locations in the Gulf of Alaska in September 1990 were compared to the composition and size of zooplankton collected in concurrent plankton tows. The maximum length of prey consumed increased dramatically over the length range of pollock examined (58–110 mm) from approximately 7 mm to 30 mm, due mainly to the consumption of large euphausiids and chaetognaths by the bigger individuals. The maximum width of prey changed little over this size range although there was a general increase in prey width with increasing predator size. The minimum prey length and width did not change with increasing fish size. Juvenile pollock generally selected the larger prey sizes relative to what was available. Juvenile pollock showed a marked preference for adult euphausiids and decapod larvae and an avoidance of copepods and chaetognaths relative to the numbers collected in net tows. These results are discussed relative to the feeding ecology of these juvenile fishes. This revised version was published online in July 2006 with corrections to the Cover Date.     

Adaptive winter survival strategies: defended energy levels in juvenile Atlantic salmon along a latitudinal gradient

Current knowledge suggests that patterns of energy storage and depletion in animals are governed by behavioural trade-offs between risks associated with feeding and future energy demands. However, the length of adverse periods varies over geographical or climatic gradients. To explore the potential for genotypic sources of variation in behavioural trade-offs, we compared the winter energy-depletion patterns among 13 wild populations of juvenile Atlantic salmon (Salmo salar L.) along a latitudinal gradient (58–70°N) and performed common-environment experiments of energy-state-dependent feeding. In the wild, winter lipid-depletion rates were lower for northern than for southern populations. The variation in spring lipid levels among the population was lower than autumn variation, with storage lipid levels clustered close to critical limits for survival. In semi-natural stream channels with natural food supply, hatchery-reared fish originating from northern populations showed a positive scaling of feeding activity with decreasing energy levels, whereas southern populations did not. In conclusion, juvenile Atlantic salmon from northern populations defend their energy levels more strongly than fish from southern populations. Adaptive variation in feeding activity appears important for this difference. Thus, the present study shows a link between geographical patterns in storage energy trajectories and adaptive differences in state-dependent feeding motivation.     

Seasonal variation of organogenetic activity and reserves allocation in the shoot apex of Pinus pinaster Ait

BACKGROUND AND AIMS: To understand better the basic growth characteristics of pines and the fundamental properties of the shoot apical meristem (SAM), variations within the shoot apex of buds were studied. METHODS: A detailed structural comparison of meristem dimensions, organogenetic activity, and the presence of lipids, starch grains and tannins was performed on shoot apices of juvenile, and male and female adult Pinus pinaster at five different times in the annual growth cycle. KEY RESULTS: There were significant correlations among traits and differences in the pattern for juvenile and adult shoots. In juvenile shoots, peaks of organogenesis were present in spring and autumn, but not in summer. In adult shoots, one peak, characterized by an increase in meristem dimensions, was present in summer. The accumulation of starch grains beneath the SAM and of tannin in sub-apical pith parenchyma were at their maximum when organogenetic activity was high in spring and autumn in juvenile plants, and in summer in adult plants. In juvenile and adult plants, lipids were stored within the SAM in autumn, filling a large part of the bud in winter, and were depleted in the cortical parenchyma and then in the pith during shoot elongation. CONCLUSIONS: Depending on the sites of accumulation within the SAM and on the stage of the annual growth cycle, lipids, starch and tannins may be involved in different processes. In spring, energy and structural materials released by lipid hydrolysis may contribute to stem elongation and/or cell-to-cell communication. During organogenesis, energy and structural materials released by starch hydrolysis may influence developmental programmes in the SAM and adjacent cells. Tannins may be involved in cellular detoxification. At the end of the growing season, accumulation of lipid and starch is positively correlated with the onset of dormancy.     

Skate assemblage on the eastern Patagonian Shelf and Slope: structure, diversity and abundance

The eastern Patagonian Shelf and continental slope of the south-west Atlantic Ocean support a high biodiversity and abundance of skates. In this study, meso-scale differences in the assemblages, spatial and seasonal distributions of skates are revealed among six habitat zones of the eastern Patagonian Shelf characterized by distinctive oceanographic conditions. Most skates belonged to temperate fauna, and their abundance was much greater in habitats occupied by temperate waters (north-western outer shelf) or mixed waters (northern slope) than in habitats occupied by sub-Antarctic waters (SASW) (south-eastern outer shelf and southern slope). Sub-Antarctic skates were not abundant on the shelf even in habitats occupied by SASW, occurring mainly in deep areas of the lower continental slope. The majority of temperate skates migrated seasonally, shifting northward in winter and spreading southward with warming waters in summer. Most temperate species had two peaks in female maturity (mainly spring and autumn) and spawned in the same habitats where they fed. It is hypothesized that the high biodiversity and abundance of skates on the Patagonian Shelf and Slope are due to the practical absence of their natural competitors, flatfishes, which occupy similar eco-niches elsewhere.     

Surviving north of the natural range: the importance of density independence in determining population size

The relative importance of density-dependent and -independent processes in determining population density has been predicted to vary according to whether the population concerned is located near the centre or the periphery of the species' range. Thus, density-independent processes should be more pronounced near the periphery. The long-tailed wood mouse Apodemus sylvaticus in Iceland is at the northern and western edge of its geographical range. We estimated the autumn population density in an open habitat in south-western Iceland in 9 years out of 10 during 1996–2005 in order to monitor the annual maximum population size. Furthermore, we estimated population density and survival at c . 5-week intervals from September 2001 to October 2003 and from September 2004 to November 2005 in order to reveal the causes of variation in maximum population size. The estimated autumn population density was low, ranging from 2.7 to 8.9 mice ha⁻¹ while spring densities ranged from 0.4 to 0.8 mice ha⁻¹. Apparent monthly survival probabilities ranged from 0.4 to 0.7 per month in autumn and 0.7 to 0.9 in winter. Our results suggest that low temperature in early winter (October–December) is the major determinant of population density in the following autumn, explaining 74% of the variation in autumn population density. No significant correlation was found between either the NAO index or the NAO winter index and variation in wood mouse population density in autumn. Differential mortality in early winter results in variation in spring population size. This study shows clear evidence of density-independent control of a mammal population at the edge of its geographical range as opposed to the mostly density-dependent control previously recorded near its centre of distribution.     

Feeding ecology of rooks (Corvus frugilegus) on the Heretaunga Plains,Hawke's Bay,New Zealand

Abstract

The food resources of rooks were measured and related to changes in the birds' feeding behaviour during 1968-1970. In all, 381 birds were individually marked with wing tags and colour-coded leg bands and released; their activities were recorded for set periods. Rooks preferred to eat invertebrates and walnuts, but also took seed of cereals, pulses, and stock feeds. They spent at least 40% of their feeding time (75-80% in spring) eating invertebrates, 30-60% finding or hiding walnuts and sometimes acorns in autumn and winter, and 45% eating seed during hot, dry weather in summer. Up to 6% of feeding time was spent eating newly sown or ripening seed. Throughout winter rooks frequently searched for hidden nuts, which they ate or moved to new positions. The proportion of time they spent feeding and the kind of food taken varied seasonally and, in summer and winter, hourly; there were only slight differences between morning, mid-day, and afternoon periods. Rooks spent 65% of the time feeding in autumn, but only 25-30% in spring. Conversely, they spent longer at nest sites from late autumn, peaking at 60% in spring, then less time at nests as they spent longer searching for food. The size of flocks altered with the food being eaten and therefore with season and time of day. Small flocks were widespread where favoured food was plentiful in autumn, winter, and spring, but flocks were larger where food was unevenly abundant in summer and sometimes in winter. During early autumn each bird usually ate and stored walnuts in a selected area of 1-2 km3, returning there later in the season to recover stored nuts. The areas formed only part of the total range used by the study population, and were usually shared with other birds. Tests in aviaries showed that rooks preferred earthworms and walnuts to acorns, maize, and wheat (in that order), and field tests confirmed that rooks preferred walnuts to maize. The numbers of each food item required to sustain a rook for a daylight hour were estimated. Summer is the most difficult season for rooks to find food.     

洞庭湖光泽黄颡鱼食性研究

根据2004年4月至2005年2月在洞庭湖逐月采集到的胃含物样品,对光泽黄颡鱼摄食习性进行了研究。结果表明,光泽黄颡鱼全年摄食,在繁殖期摄食强度下降。共鉴定17类饵料生物,食物多样性指数春季最高,冬季最低。水生昆虫幼虫和甲壳类为其主要食物,二者在食物中所占重量百分比为90.6%。摄食的水生昆虫主要为蜉蝣目稚虫(数量百分比:24.2%;重量百分比:41.1%)、双翅目幼虫(数量百分比:58.4%;重量百分比:7.5%)和蜻蜓目稚虫(数量百分比:3.2%;重量百分比:22.8%)。光泽黄颡鱼的食物组成在季节上存在明显差异。从数量百分比看,春季和冬季均以双翅目(秋季64.6%;85.0%)为主,夏季以双翅目(28.2%)和蜻蜓目(22.3%)为主,秋季以蜉蝣目(45.7%)为主;从重量百分比看,春季以双翅目(53.0%)为主,夏季以蜻蜓目(55.7%)为主,秋季和冬季以蜉蝣目(秋季53.7%;冬季76.6%)为主。分析表明,光泽黄颡鱼食物组成的季节差异与食物资源的季节动态紧密相关。       

Distribution and some features of biology of rock greenling <Emphasis Type="Italic">Hexagrammos lagocephalus</Emphasis> in Pacific waters off the northern Kuril Islands and southeastern Kamchatka

Based on materials of trawl studies performed from 1992 to 2002 off the Pacific coast of Kamchatka and the northern Kuril Islands in the framework of the integrated (VNIRO, KamchatNIRO, Sakh-NIRO) program on the study of fishery resources of the continental slope, data on the distribution and biology of rock greenling Hexagrammos lagocephalus were analyzed. It was elucidated that this species is extremely eurybathic; the range of its seasonal vertical migrations embraces depths of 1–2 m in summer, and in the spawning period and up to 665 m in winter. The spatial distribution has a mosaic pattern, maximum concentrations were recorded at the slope and shelf of the Shumshu Island and the southern extremity of Kamchatka. The size, weight, and sex composition, and the maturation and feeding of the rock greenling are considered. Maximum fish sizes in trawl catches are 58 cm and 2.63 kg; sex composition is characterized by the domination of females in all size groups (79%). The bulk of feeding consisted of Cephalopoda, small crustaceans—Amphipoda and Isopoda—as well as the eggs of fish and Gastropoda. With an increase in sizes, the greenling passes from feeding on small benthic organisms to larger movable forms.     

Relationship between the distribution of euphausiids and baleen whales in the Antarctic (35°E – 145°W)

Simultaneous whale sighting and hydroacoustic surveys were conducted from a research vessel in the Antarctic to examine the relationship between the distribution of euphausiids and baleen whales. High densities of minke whales and large aggregations of euphausiids were observed along the ice edge over the continental slope in the southeast region of area IV and in the southwest region of area V. The results suggest that the continental slope zone that coincides with the ice edge would be an important minke whale feeding area. Minke whales were rarely sighted in the offshore region even if euphausiids were abundant. Distributions of humpback whales were correlated with high euphausiid density zones, regardless of the bottom topographic features. Several groups of blue whales were sighted in the small area along the ice edge where euphausiids were abundant, but sightings were too few to draw any general conclusion about the relationship between blue whales and euphausiids. Both baleen whales and euphausiids were scarce in the area east of 170°W where sea ice covered the continental shelf and slope zone.     

Community structure of deep-sea demersal fish in the North Aegean Sea (northeastern Mediterranean)

The spatial structure and seasonal changes of the demersal fish assemblages on the continental shelf (100–200 m) and upper slope (200–500 m) in the North Aegean Sea (Northern Aegean and Thracian Seas, northeastern Mediterranean, Greece) were analysed. Seasonal experimental trawl surveys, carried out from summer 1990 to autumn 1993, provided a total of 151 demersal fish species. Analysis of 259 bottom trawls showed the existence of four groups associated with the continental shelf and the upper slope; each group was dominated by a small number of species. The bathymetric distribution of the species, established using measures of the centre of gravity and habitat width, revealed that most of the species had a wide distributional range within the study area, although a few were restricted to the greatest depths. Density, biomass, species richness and diversity decreased significantly with depth, and were also indicative of distinctive characteristics between these fish assemblages. Mean fish weight exhibited two different trends: a bigger-deeper phenomenon at the continental shelf and a smaller-deeper phenomenon at the upper slope. The variability in assemblage structure was determined mainly by depth and, to a lesser extent, by season and geographical location. For some species, results suggest a pattern of gradual species replacement along the depth gradient coupled with ontogenetic habitat shifts.     

Short-term study testing the resilience of an estuarine bivalve to macroalgal mats

Increased mortality of juvenile Atlantic salmon (Salmo salar L.), related to lowered levels of stored energy following the loss of ice cover during winter, has been observed after hydropower development in the subarctic River Alta, northern Norway. Drift samples were compared to examine if drift densities, and thus drift prey availabilities for juvenile salmon, were lower in the ice-free than the ice-covered area. In addition, juvenile salmon stomach contents were compared to benthos and drift in the ice-free area to examine salmon winter feeding habitat. Zooplankton, originating from the reservoir, dominated drift at the ice-free site but had lower densities at the downstream ice-covered site. Excluding zooplankton, Chironomidae comprised most of the remaining drift at both the ice-free and ice-covered site, followed by Ephemeroptera, Plecoptera and Simuliidae. No Trichoptera were found in the drift samples. There was no consistent diel periodicity in drift. Benthos was dominated by Chironomidae, followed by Ephemeroptera, Plecoptera and Trichoptera. Other invertebrates occurred in low numbers. Juvenile salmon demonstrated size-selective feeding and fed mainly on Ephemeroptera, followed by Trichoptera and Plecoptera. No zooplankton and few Chironomidae were found in the stomach samples. Stomach content was more similar to benthos than to drift, indicating a larger extent of benthic than drift feeding. No evidence was found for the hypothesis that lack of ice cover reduced the invertebrate drift or caused diel periodicity in the drift. Differences in drift between areas with and without ice could not account for the observed differences in mortality of juvenile salmon during the winter in these areas.     

Changes in lipid and fatty acid composition of late larval and puerulus stages of the spiny lobster (Panulirus cygnus) across the continental shelf of Western Australia

The feeding of the late larval stages of the spiny lobster, Panulirus cygnus, and the energy reserves used by the non-feeding post-larvae for crossing the continental shelf of Western Australia were examined through their lipid composition. Lipid was a significant component of the biomass of all larval and post-larval samples (range 63-213 mg g(-1) of dry biomass). The fatty acid profiles of late stage larvae (8-9) suggest that they were feeding on salps and small crustaceans, such as euphausids, from oligotrophic pelagic communities where herbivorous and microbial grazing is an important basis to the food web. There was a marked decrease in lipid content of post-larvae progressively across the continental shelf, and this corresponded closely with decreasing dry mass, suggesting that post-larvae were using lipid as an energy source during cross-shelf movement at a rate of 1.6 J km(-1). This is considerably lower than for other spiny lobster species, suggesting that the post-larvae of the western rock lobster may use physical processes as well as active swimming for onshore transport. This may help to explain the large inter-annual variability in the post-larval settlement of this species, which is closely related to differences in weather patterns capable of greatly varying onshore advection processes.     

基于生境可获得性的完达山地区马鹿(Cervus elaphus xanthopygus)冬季生境选择

于2004～2005年冬季研究了完达山地区马鹿的生境利用和选择。在野外调查的基础上,获取了研究地区马鹿种群水平上的生境利用数据;利用地理信息系统和遥感技术,从区域尺度上测度了各类生境因子的可获得性。通过比较被利用生境与可获得生境,测度了马鹿冬季对各类生境或生态因子的选择。结果表明,马鹿对植被类型、海拔、坡向、NDVI等级、到公路距离表现出非比例利用,对坡度的利用与其可获得性则没有显著性差异。马鹿选择采伐迹地,低郁闭度生境（第2、3NDVI等级）,200～300m海拔区间,南坡,距离公路600～700m的区间。马鹿采食生境和卧息生境对各类因子具有不同的选择性,表现出不同功能生境分离的特征。对于采食生境,马鹿选择采伐迹地、阔叶疏林,低郁闭度（第2、3NDVI等级）,南坡;对于卧息生境,马鹿仅选择采伐迹地,低郁闭度（第2、3、4NDVI等级）。根据马鹿活动样点的出现与否,建立了马鹿冬季生境选择的逻辑斯谛回归模型。模型回判结果表明,该模型对马鹿活动样方与对照样方的总体正确预测率为74．4％,对马鹿活动样方的正确预测率为84．2％,对对照样方的正确预测率为62．4％,能够较好的预测生境利用概率。     

Seasonal patterns of winter flounder Pseudopleuronectes americanus abundance and reproductive condition on the New York Bight continental shelf

To resolve varied and sometimes conflicting accounts of spawning and habitat characteristics for winter flounder Pseudopleuronectes americanus, seasonal patterns in abundance and reproductive condition were investigated in the New York Bight, near the southern edge of their current reproductive range. Fish were collected from trawl surveys on the inner continental shelf from October 2006 to October 2007. Pseudopleuronectes americanus were most abundant during January and April surveys, were rarely collected in August, with intermediate abundances in June and October. Measurements of fish condition [hepato‐somatic index (I_H), condition factor (K) and the per cent dry mass of muscle tissue (%M_D)] and reproductive condition [gonado‐somatic index (I_G)] were determined to evaluate seasonal changes in energy accumulation and depletion and reproduction. Males and females had similar patterns in body and reproductive condition, although the magnitude of change was greater for females. I_H values were highest during spring and early summer, suggesting increased feeding following spawning. K and %M_D increased through spring and summer then declined in the autumn and winter concurrent with gonadal development. Gonads began developing in the autumn, and in January, I_G values approached spawning levels, with many spent individuals collected in spring. Within these general patterns, however, there was a large degree of variability among individuals, and a few mature non‐reproductive (‘skipped spawning’) females were observed. In the period after spawning, increased energy intake, indicated by increased I_H, may influence reproductive output since this energy is gradually transferred to the muscle and used for gonadal development in the forthcoming year. The occurrence of ripening individuals on the inner continental shelf in January suggests that these fish either rapidly move into estuaries to spawn by February–March or they remain on the inner shelf to spawn, or some combination of these. Future studies should evaluate these possibilities, as both estuarine and inner shelf habitats are potentially affected by activities such as dredging, sand dredging and wind energy development.     

Effect of temporary reductions in feeding on protein synthesis and energy storage of juvenile Atlantic salmon

Biochemical and tissue-composition indices were used to determine the impacts of temporary feeding reductions on juvenile Atlantic salmon (4.2g initial weight). Three levels of food reduction (fasting, 20% of control, 50% of control) lasting for 2, 4 or 8 days were compared to a control group (constant feeding at 2.75% of body weight day⁻¹). Ornithine decarboxylase (ODC) activity and RNA concentrations were used to measure changes in protein synthesis; condition factor ( K) , liver-somatic index (LSI), visceral-somatic index (VSI), and gut index (GI)were used to provide information on stored energy levels. Results showed that physiological adjustments to decreases or increases in feeding occur very quickly. The most rapid responses were changes in ODC activity (within 2 days) and LSI (2–4 days). Changes in RNA concentrations and K required 4–8 days. There was no apparent effect of the treatments on VSI or GI. Temporary reductions of feeding lasting 2 days or less would not be detected by any index except ODC activity. Changes in the indices are discussed with respect to short-term changes in rates of protein synthesis and energy storage.     

Right whale occurrence in the coastal waters of Virginia,U.S.A.: Endangered species presence in a rapidly developing energy market

The endangered North Atlantic right whale is susceptible to increased risks associated with the developing energy market off the Virginia coast of the U.S.A., including increased noise exposure from shipping and energy exploration and extraction, and shipping activity. Primarily viewed as a migratory corridor between northern feeding and mating areas and the southern calving area, Virginia waters have not been intensely monitored for right whales. We conducted a 1 yr, continuous, passive acoustic survey from the Virginia coast to the continental shelf to better describe the seasonal occurrence and spatial distribution of right whales in this area. We found that whales were acoustically detected in every month of the year, with increased seasonal occurrences in fall and late winter/early spring, and not just during limited periods of the year. As industry activities continue to increase in the area, these new right whale occurrence data have implications for siting and permitting of offshore energy activities.