Summer Feeding Research Articles

Comparative assessment of the seasonal breeding patterns of the paddlefish Polyodon spathula (Walbaum, 1792) and the impact of growth tendency during winter and summer feeding

Comparative assessment of the seasonal breeding patterns of the paddlefish Polyodon spathula (Walbaum, 1792) and the impact of growth tendency during winter and summer feeding

Assessing the Geoecological Status of the Floodplain-Terrace Complex of the Tuul River Within Ulaanbaatar (Mongolia)

The paper gives characteristics of natural and anthropogenic factors responsible for the geoecological situation inside the boundaries of the floodplain-terrace complex of the Tuul river within Ulaanbaatar. Among them, the geological structure and orography (occurrence in the intermontane depression), the specific character of climate-forming (frequent temperature inversions) and hydrological (mainly summer feed by rain water) characteristics, the degree of economic development (high pressure on the central city zone) and population density in administrative districts, etc. have been distinguished. Results obtained from hydro- and geochemical analyses of the territory and published previously (during 2009–2013) were used in the typification of the areas of the floodplain-terrace complex of the Tuul river according to the intensity of anthropogenic impact. An analysis was made of the sources of pollution, primarily of large industrial enterprises and facilities of housing and communal services: combined heat and power plants, industrial, meat-packing and biological plants, the poultry farm, sewage treatment plants, etc. Based on a comparative analysis of average concentrations of the component composition of the river waters and floodplain soils, maximum exceedances of maximum and approximate permissible concentrations of pollutants were determined. Categories of the intensity of anthropogenic impact were identified to vary from decreased to very high. It is shown that, in spite of a high degree of geochemical understanding of the urban territory of Ulaanbaatar, no detailed investigations have been made within the floodplain-terrace complex of the Tuul river. The first-time assessment of the geoecological status of the sites across the study territory determined the migration routes of chemical substances and correlated their occurrence in natural environment with the sources of pollution. According to the intensity of anthropogenic impact, for each site of the floodplain-terrace complex we have suggested environmental and water protection measures. Results of the assessment are presented in the form of cartographic material.

New insights into prime Southern Ocean forage grounds for thriving Western Australian humpback whales

Humpback whale populations migrate extensively between winter breeding grounds and summer feeding grounds, however known links to remote Antarctic feeding grounds remain limited in many cases. New satellite tracks detail humpback whale migration pathways from Western Australia into the Southern Ocean. These highlight a focal feeding area during austral spring and early summer at the southern Kerguelen plateau, in a western boundary current where a sharp northward turn and retroflection of ocean fronts occurs along the eastern plateau edge. The topographic steering of oceanographic features here likely supports a predictable, productive and persistent forage ground. The spatial distribution of whaling catches and Discovery era mark-recaptures confirms the importance of this region to Western Australian humpback whales since at least historical times. Movement modelling discriminates sex-related behaviours, with females moving faster during both transit and resident periods, which may be a consequence of size or indicate differential energetic requirements. Relatively short and directed migratory pathways overall, together with high-quality, reliable forage resources may provide a partial explanation for the ongoing strong recovery demonstrated by this population. The combination of new oceanographic information and movement data provides enhanced understanding of important biological processes, which are relevant within the context of the current spatial management and conservation efforts in the Southern Ocean.

370 Predicting nitrogen and phosphorous flows in beef open lots

Abstract This research summarizes a large existing data base collected over fifteen years to examine origin and fate of nitrogen and phosphorous in an open lot beef system, as impacted by seasonal changes, diets, and management practices. Data from 15 winter trials, including 200 pens, and 15 summer trials, including 216 pens were reviewed for nutrient mass balance, which was then used to determine the correlations of season, diet, and management with nitrogen and phosphorous intake, retention, manure harvested, loss, and runoff. All relationships were evaluated using linear regression SAS. Results suggested N in harvested manure for winter and summer averaged 90 and 51 g/steer daily, respectively (compared to ASABE standard of 88.5) and P harvested in manure for winter and summer averaged 26 and 17.7 g/steer daily, respectively (compared to ASABE standard of 37.5). Results of this summary show that the amount of nitrogen lost and retained in the manure is correlated to season (winter versus summer feeding period). Nitrogen in the manure (R2=0.21) and amount lost (R2=0.65) correlations with N intake in the summer were greater compared to winter (R2=0.06) and (R2=0.22). There is a greater correlation of phosphorous intake with amount harvested in manure (R2=0.32) in the winter versus the summer (R2=0.19). Results of the mass balance data compared with ASABE standards suggest greater observed dietary nutrient intakes than assumed by these standards. For example, average winter and summer nitrogen intakes of 220 and 250 g/steer daily exceeds the ASABE standard of 192 g/steer daily. These unique data describe the variability of nutrient recovery and losses from beef systems—and the importance of basing standard planning estimates on dietary concentration and evolving with current practices.

Arctic charr brain transcriptome strongly affected by summer seasonal growth but only subtly by feed deprivation

BackgroundThe Arctic charr (Salvelinus alpinus) has a highly seasonal feeding cycle that comprises long periods of voluntary fasting and a short but intense feeding period during summer. Therefore, the charr represents an interesting species for studying appetite-regulating mechanisms in fish.ResultsIn this study, we compared the brain transcriptomes of fed and feed deprived charr over a 4 weeks trial during their summer feeding season. Despite prominent differences in body condition between fed and feed deprived charr at the end of the trial, feed deprivation affected the brain transcriptome only slightly. In contrast, the transcriptome differed markedly over time in both fed and feed deprived charr, indicating strong shifts in basic cell metabolic processes possibly due to season, growth, temperature, or combinations thereof. The GO enrichment analysis revealed that many biological processes appeared to change in the same direction in both fed and feed deprived fish. In the feed deprived charr processes linked to oxygen transport and apoptosis were down- and up-regulated, respectively. Known genes encoding for appetite regulators did not respond to feed deprivation. Gene expression of Deiodinase 2 (DIO2), an enzyme implicated in the regulation of seasonal processes in mammals, was lower in response to season and feed deprivation. We further found a higher expression of VGF (non-acronymic) in the feed deprived than in the fed fish. This gene encodes for a neuropeptide associated with the control of energy metabolism in mammals, and has not been studied in relation to regulation of appetite and energy homeostasis in fish.ConclusionsIn the Arctic charr, external and endogenous seasonal factors for example the increase in temperature and their circannual growth cycle, respectively, evoke much stronger responses in the brain than 4 weeks feed deprivation. The absence of a central hunger response in feed deprived charr give support for a strong resilience to the lack of food in this high Arctic species. DIO2 and VGF may play a role in the regulation of energy homeostasis and need to be further studied in seasonal fish.

Encouraging encounters: unusual aggregations of bowhead whales Balaena mysticetus in the western Fram Strait

The subpopulation of the bowhead whale Balaena mysticetus in the East Greenland-Svalbard-Barents Sea is endangered and until recently was believed to number in the tens. Recent studies have suggested that this subpopulation appears to be increasing. Here, we report on unusual aggregations of bowhead whales within the Fram Strait. We present opportunistic and effort-corrected observations of bowhead whales made from a small expedition vessel during cruises in June (2015−2018). Bowhead whales were sighted on 85 occasions (220−227 whales). An aggregation in 2015 (n = 84 whales) and high numbers in 2018 (n = 104−110) exceeded all previous records. The index of whale abundance was significantly higher in open water-leads (1.08−1.14 whales km−1 of survey effort) compared to areas with drift-ice (0.51−0.53 whales km−1). The highest abundance index was measured in deep waters where the bottom slope was relatively steep. Our findings highlight the temporal and spatial consistency of this species in areas with relatively loose ice cover (open water-leads) and steep slopes. It is unknown how global warming and resultant changes in ice-extent are going to affect bowhead whales within the Strait and whether they will find new feeding grounds due to an expanding open-ocean habitat. These slopes may become increasingly important to bowhead whales and Arctic top predators as a spring/early summer feeding ground. These relatively large numbers of bowhead whales are encouraging and can help direct future research monitoring programs to study the population ecology of these endangered whales.

Perceptions of the Summer Food Environment in a Rural Appalachian Mississippi Community by Youth (P04-153-19)

ObjectivesTo explore the perceptions of the youth regarding the summer food environment in a rural Appalachian Mississippi community using photovoice methodology. MethodsA 4-week summer food education program was implemented in an economically-distressed community in a rural Appalachian Mississippi community. The program included STEM education with a food-based curriculum and provision of lunch to youth participating in the summer reading program in a public library. Eleven youth, 13 to 18 years were recruited, and 5 (45%) students completed the study. Participants received an introduction to photovoice, a disposable camera, a log book, a handout of photography tips, and photo release forms. Participants also took part in a focus group to engage in dialogue about the meaning of their pictures and to record their perceptions, opinions, attitudes, and experiences about the local food environment. The naturalized approach was utilized to transcribe the focus group meeting, followed by color coding and assigning pseudonyms. Transcripts were coded using NVivo 11 and analyzed for key themes. Firstly, transcripts were coded independently, then themes were generated using a collaborative approach. Data were analyzed using grounded theory, including the open-coding method (Initial coding), followed by in-vivo coding and focused coding. ResultsAnalysis of photographs, log books, and focus group data revealed 7 themes related to a healthier summer food environment, including: 1) improved availability of and access to a healthier, affordable food supply; 2) improved availability and access to charitable food organizations; 3) implementation of child feeding programs when school is not in session; 4) development of a community kitchen; 5) improved communication about the food assistance programs; 6) encouragement of home and community gardening; and 7) improved employment opportunities and work ethic. ConclusionsThese results present insights by youth into the unique challenges of this community and facilitation of a healthier food environment. Engagement of youth in the development of a summer feeding program is warranted as an initial step to improving the food environment for youth. Funding SourcesNIH SEPA; UM Foundation Food and Nutrition Security Support Fund (Donor: Monsanto).

Summer survival and activity patterns of estuary feeding anadromous Salmo trutta

AbstractThere is generally a very poor understanding of how anadromous brown trout, Salmo trutta, use marine ecosystems. In this study, we use acoustic telemetry techniques to test four alternative hypotheses for estuarine coastal habitat use by this species on a population in the Clyde, west‐central Scotland. Anadromous brown trout in their second (or more) summer feeding in the marine environment did not show patterns of estuarine use predicted from studies on other populations of this species. They did not (a) use the inner Clyde Estuary as a staging post for onward migration to open coastal waters, nor did they (b) pass through the estuary rapidly nor did they (c) make multiple incursions into freshwater. In contrast, fish utilised a very geographically constrained area of the inner estuary (<8 km in length), within which fish were highly mobile, exhibiting more activity during a flooding tide and exhibited high survivorship compared with reports from other studies. The reasons why estuarine use by anadromous brown trout in the Clyde may differ from that reported elsewhere is discussed.

Lipid content in overwintering Calanus finmarchicus across the Subpolar Eastern North Atlantic Ocean

AbstractThe boreal copepod Calanus finmarchicus accumulates lipid reserves during summer feeding in surface ocean waters, which enable it to stay at depth and survive famine during overwintering. Respiration of lipids during prolonged overwintering at ocean depths (> 1000 m in some areas) has been shown to result in a net sequestration of carbon into the deep ocean: the so‐called “lipid pump.” Here, we provide a comprehensive synthesis of the geographic and vertical variations in lipid content of overwintering animals across the Subpolar Eastern North Atlantic and, on the basis of this, we revise the estimates of carbon sequestration. Wax ester content ranged from 40 to 190 μg individual−1 at > 250 m depths, with highest concentrations in the coldest (< 0°C) waters at 400–600 m depth at the slope east of Faroe Islands and east of Greenland and lowest in the warmer (> 4°C) Irminger Sea and Rockall Basin. Our new analysis results in about 44% higher estimates of carbon sequestration at up to 11.5 g C m−2.

The Dependence of the Duration of Downstream Migration of Burbot (Lota lota) Larvae on the Hepatosomatic Index of Spawners

This study estimates the dependence of the duration of the downstream migration of burbot larvae in the Voikar River (the Lower Ob basin) on the relative condition factor of semianadromous spawners migrating upstream to the spawning tributary in autumn; the estimates are based on 20 years of observations (from 1999 to 2018). The observed (11 years) and calculated (9 years) values of the hepatosomatic index were used to estimate the relative condition factor of spawners. The values of the hepatosomatic index were calculated using the median quantile regression based on estimates of the maximum level of floodplain flooding and sum of daily average water temperatures during the open channel period in summer feeding areas. A strong, highly significant negative dependence of the duration of downstream migration of juveniles and of the number peaks of abundance larvae on the values of the hepatosomatic index of spawners has been revealed. It is assumed that there is a relationship between the relative condition factor of spawners and the timing of their upstream migration to spawning grounds. In turn, the upstream migration time determines the accessibility of river spawning areas for spawners, which then determines the timing of hatching of burbot larvae.

Life at the top: Lake ecotype influences the foraging pattern, metabolic costs and life history of an apex fish predator.

We used acoustic telemetry and acceleration sensors to compare population-specific measures of the metabolic costs of an apex fish predator living in four separate lakes. We chose our study species and populations to provide a strong test of recent theoretical predictions that optimal foraging by an apex fish predator in a typical aquatic environment would be consistent with feeding to satiation rather than continuous feeding. We chose four populations where the primary prey type differed along a body size gradient (from small invertebrates to large planktivorous fish) and along a thermal accessibility gradient (from easily accessible cold-water pelagic prey to less accessible warm-water epilimnetic and littoral prey). We expected that these gradients in prey type would evoke distinctly different activity gradients depending on whether predators fed to satiation (e.g., less frequent "rest" detections where primary prey are smaller/less accessible) or fed continuously (e.g., fixed level of "rest" detections under all prey conditions). Our study organism was a fall spawning, cold-water visual apex predator (lake trout). Therefore, we focused our study on diel (early night, dawn, day, dusk, late night) changes in metabolic costs associated with summer feeding behaviour. The duration (~20days) and fine temporal scale (~30min) of our behavioural data provided a uniquely detailed picture of intra- and inter-population differences in activity patterns over a critical period in the annual growing season. In all populations, diel shifts in activity were qualitatively consistent with that expected of a visual predator (e.g., resting state detections were most frequent at night). Between-lake differences in daytime thermal experience were qualitatively consistent with between-lake differences in the location of primary prey (e.g., excursions to warm habitats were common in lakes with epilimnetic/littoral fish as primary prey and relatively rare in lakes with pelagic cold-water invertebrates/fish as primary prey). Daytime activity patterns were more consistent with the feeding pattern expected from feeding to satiation rather than continuous feeding: (a) individuals in all four populations exhibited clearly delineated bouts of resting behaviour and active behaviour; (b) the frequency of resting bouts and the resultant overall cost of daily activity were strongly associated with the size and accessibility of prey-in lakes with smaller and/or less accessible prey, predators rested less frequently, exhibited marginally higher costs when active and had higher overall daytime activity costs. Within each lake, similar changes in activity occurred concurrently with diel changes in prey accessibility/relative density.

Subarctic singers: Humpback whale (Megaptera novaeangliae) song structure and progression from an Icelandic feeding ground during winter.

Humpback whale songs associated with breeding behaviors are increasingly reported outside of traditional low latitude breeding grounds. Songs from a subarctic feeding ground during the winter were quantitatively characterized to investigate the structure and temporal changes of the songs at such an atypical location. Recordings were collected from 26. January to 12. March, 2011, using bottom mounted recorders. Humpback songs were detected on 91% of the recording days with peak singing activities during 9.–26. February. The majority of the recordings included multiple chorusing singers. The songs were characterized by a) common static themes which transitioned consistently to predictable themes, b) shifting themes which occurred less predictably and c) rare themes. A set median sequence was found for four different periods (sets) of recordings (approximately 1 week each). The set medians were highly similar and formed a single cluster indicating that the sequences of themes sung in this area belonged to a single cluster of songs despite of the variation caused by the shifting themes. These subarctic winter songs could, thus, represent a characteristic song type for this area which is comparable to extensively studied songs from traditional low latitude breeding grounds. An increase in the number of themes per sequence was observed throughout the recording period including minor changes in the application of themes in the songs; indicating a gradual song progression. The results confirm that continual singing of sophisticated songs occur during the breeding season in the subarctic. In addition to being a well-established summer feeding ground the study area appears to be an important overwintering site for humpback whales delaying or canceling their migration where males engage in active sexual displays, i.e. singing. Importantly, such singing activity on a shared feeding ground likely aids the cultural transmission of songs in the North Atlantic.

Влияние природной минеральной добавки смектитного трепела в составе зерновой кормосмеси на продуктивность телят в молочный период

The effect of smectite tripoli in the grain feed mixture in summer and winter periods was studied via two experiments on the black and motley breed calves in the SEC Agricompany Culture in the Bryansk region. Three groups (each of 10 livestock units) were selected for the trial. The main feed was whole milk. The composition of grain feed in summer included smepitny tripoli in the amount of 15 and 20 g/day per head. In winter, 30 and 40 g of natural mineral additive were included in the grain feed mixture. The results show that in the summer period in the experimental and control groups live weight of calves and average daily gains were almost equal. However, in winter, in the second experimental group that was fed 30 g of natural mineral additive smectite tripoli the average daily gain in calves was more by 5.9%, which allows to conclude that 30 g of smectite tripoli in the grain feed in the winter period is the optimal dose for calves. The analysis of economic efficiency showed that feeding smectite tripoli in the grain feed mixture in the milk period significantly influenced the profit in the second experimental group, where it was 30.6% more than in the control group. In the group that received 40 g of smectite tripoli in the grain feed mixture the profits were less by 6.1%.

North Atlantic right whales (Eubalaena glacialis) in Irish Waters: 1300-1987

North Atlantic right whales (Eubalaena glacialis) once occurred seasonally in Irish waters but in recent decades their presence has declined. This study reviews the existing literature to develop an understanding of the past distribution of North Atlantic right whales, their abundance, temporal occurrence, interspecies associations and apparent use of Irish waters. Ancillary information supporting these core aims was investigated to provide a context for the historical misidentification of North Atlantic right whales and the development of Irish whaling to evaluate the presence of this species in Irish waters. Records of the species within the Irish Exclusive Economic Zone (EEZ), between 1300—1987 were validated based on the available data to three confidence levels: definite, probable and possible right whales. Seventeen records comprising at least 42 individual whales exist (including probable Basque whaling effort from the fourteenth century to the sixteenth century). Of the records available, 52% were considered ‘definitely’ right whales with eight comprising 22 individuals from two early twentieth century and two mid-seventeenth century commercial whaling stations operating in the northwest of Ireland. Six ‘probable’ right whale records involving 15 individuals were identified, including two sightings from the late twentieth century while two ‘possible’ records of five individuals were also noted. The previous importance of Ireland's north western coastline as a potential early summer feeding area in the Northeast Atlantic for migrating right whales, along with the apparent extirpation of the species in the region are also discussed.

The fatty acid composition of sheep's milk of an autochthonous breed

The study included a total of 127 sheep milk samples from two different areas (Livno and Travnik) in summer feeding period (July, August and September). Fatty acids in milk were determined by gas chromatography (GC). The animals were marked with the appropriate number of ear tags on the basis of which we always took samples from the same animals through different periods. Fatty acids in milk were determined by gas chromatography and the following fatty acids composition: butyric acid, caproic acid, caprylic acid, capric acid, stearic acid, oleic acid, linoleic acid, arachidonic acid, eicosapentaenoic acid, docosahexaenoic acid, rumenic acid. The fatty acid content of sheep's milk in this study showed a tendency of variation, both within and between sampling areas, and characterized by its relatively high content of saturated fatty acid (SFA) during the period of harvest.

Interactions of season, sex and size on nutrient composition of freshwater crayfish (Astacus leptodactylus Eschscholtz, 1823) from Lake Eğirdir

Effects of interaction of season, sex and size on nutrient composition and fatty acid profiles of freshwater crayfish (Astacus leptodactylus) caught from the Eğirdir Lake were investigated on a factorial level. In the factorial analysis; 4 levels of season factors (autumn, winter, spring, summer), 2 levels of sex factor (male, female) and 1 level size factor were available. According to the results of biochemical analysis, effects of seasons were determined on crude protein and moisture levels. Crude ash levels changed depending on sex and season. There were no interactions of these three factors on the crude fat levels. The season and sex affected on LA, α-LNA and ∑HUFA levels. ARA, EPA, DHA, ∑SFA and ∑PUFA levels were affected from seasonal changes. Interaction of season/sex affected to ∑MUFA levels. The crude protein content, DHA, EPA and n-3 contents in tail muscle of A. leptodactylus increased by feeding in summer while these contents decreased by gonadal development in autumn. Therefore, in terms of nutritional protein contents, EPA, DHA and n-3 of this species were higher in summer. EPA, n-3 and DHA contents are important for A. leptodactylus.

COMPUTATIONAL MODEL TO IMPROVE DAIRY ANIMAL FEEDING UNDER MIXED FARMING SYSTEM (CROPS/LIVESTOCK) AS STUDY CASE

Computational model was designed for feeding systems of small dairy farms in Egypt under Mixed Farming System (MFS) (Crops/livestock). The present case study was selected from El-Beheira governorate, where the three common dairy animals (Local cows, Crossbred cows and buffaloes) are available. The main objectives of this study were 1- To find out the optimum combination of inputs from farm green forage and cash crops to minimize animal feeding costs. 2- Asses the possibilities of increasing the farm income by least cost rations formulation using available feed resources for dairy cattle. Technical coefficients of the models were obtained from previous studies under Egyptian condition. The model proposed three scenarios: Scenario I (S I) calculated the actual feeding situation from the case study without any changes as base run, scenario II (S II) proposed to cover animal feeding requirements of the same herd in scenario (S I) from the same available feed resources according to NRC (2001) and scenario III (S III) operating on the available feeding package quantities or reallocated farm feed resources for the same herd. The model used the common feed in summer and winter seasons (300 days) while, two months were considered as transitional period between two seasons, where irregular animal feeding regime is adopted. The results showed that area cultivated with green forages can be reduced by 17% and 25% of total planted area in SII for winter and summer, respectively, compared to base run (SI). Where as in S III, the green forage cultivated areas reduced by 30% and 25% for winter and summer, respectively in comparison with SI, feeding costs in SII were reduced by 51.11% and 38.97% in winter and summer, respectively. Using available feeding packages and reallocated farm resources in SIII reduced feeding costs by 47.78% and 27.67% for winter and summer, respectively. It can be concluded that using available feeding packages or reallocated animal feeding resources either in SII and SIII achieved a considerable reduction on animal feeding costs of small-scale mixed farms compared to base run scenario (SI).

Nutritional correlates of spatiotemporal variations in the marine habitat use of brown trout (Salmo trutta) veteran migrants

The brown trout (Salmo trutta) is an iteroparous, anadromous salmonid that exhibits a complex continuum of feeding migration tactics, ranging from freshwater residency, to potamodromy, to estuarine migration, as well as short- to long-distance coastal migrations. While anadromous migrants are believed to play an important role in the species’ population dynamics, little is known about the factors driving differences in the extent of individual marine habitat use. In this study, 32 brown trout veteran migrants were acoustically tagged prior to their seaward migration and sampled for indices of their nutritional state. Our findings suggest that (i) body condition factor differed among fish adopting different migratory tactics, with outer fjord migrant being in poorer condition; and (ii) within migratory groups, plasma triglyceride concentration was negatively correlated with the duration of marine residency. Results support the idea of condition-dependent migration in veteran migrants, with individual variation in nutritional state influencing the spatiotemporal aspects of marine habitat use. Furthermore, overall marine minimum survival during the summer feeding migration was 86%, the highest reported estimate for this life stage.

Feeding ecology of capelin (Mallotus villosus) in a fjord impacted by glacial meltwater (Godthåbsfjord, Greenland)

Capelin (Mallotus villosus) is an important trophic node in many Arctic and sub-Arctic ecosystems. In Godthabsfjord, West Greenland, the zooplankton community has been shown to change significantly from the inner part of the fjord, which is impacted by several glaciers to the shelf outside the fjord. To what extent this gradient in zooplankton composition influences capelin diet during their summer feeding in the fjord is yet unknown. To investigate this, we analysed stomach content of capelin (8–14 cm) sampled using a pelagic trawl at three stations in outer (GF3), mid (GF7) and inner (GF10) part of Godthabsfjord in May and August 2013. In May, the copepod nauplii numerically dominated the diets, but euphausiids contributed > 92% by carbon mass at all stations. In August, calanoid copepods were the most important prey numerically and by carbon mass. Smaller copepod species became more important towards the inner stations, whereas the large Calanus species dominated in the outer stations. There was also a trend in decreasing stomach carbon content towards the inner stations, and on the individual level, variation in stomach content was strongly negatively related to the proportion of small copepods in the diet. This suggests that the inclusion of small copepods in the diet cannot compensate for the absence of larger euphausiids and copepods. Therefore, any change in the ecosystems that favours these at the expense of larger zooplankton and euphausiids is likely to impact capelin feeding negatively with consequences for the whole ecosystem.

Vocalizations of common minke whales (Balaenoptera acutorostrata) in an eastern North Pacific feeding ground

The minke whale (Balaenoptera acutorostrata) is the smallest species of baleen whale and has a cosmopolitan distribution. Despite extensive study on the vocalizations of other balaenopterids, the acoustic repertoire of minke whales is not well known. Individuals of the North Pacific subspecies of common minke whale (B. a. scammoni) are known to produce unique vocalizations (boings) during their putative breeding season from fall to spring. However, no vocalizations have been previously reported for this subspecies in summer feeding grounds. We present four novel call types recorded in the presence of minke whales in Cormorant Channel, in coastal British Columbia, Canada, during the summer of 2012. These calls consist of broadband pulses, tonal wavers, downsweeps, and pulse trains. Calling rates for minke whales in this study region were very low compared to those reported for North Atlantic minke whales on their feeding grounds. We compare our candidate call types with vocalizations described for other minke whale populations and propose predation risk as a cause of the low calling rates observed for minke whales in Cormorant Channel.