Correlation between the seasonal distribution of harbour porpoises and their prey in the Sound, Baltic Sea

Sveegaard, Signe; Andreasen, Heidi; Mouritsen, Kim N.; Jeppesen, Jens Peder; Teilmann, Jonas; Kinze, Carl Chr.

doi:10.1007/s00227-012-1883-z

Cited by 55 publications

(47 citation statements)

References 36 publications

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“…The importance of environmental factors such as currents, chlorophyll and nutrients was also confirmed by Danish and German studies (Edrén et al 2010, Gilles et al 2011, Sveegaard et al 2012a. In the Belt Sea and Kattegat, the geographic distribution of porpoise concentrations appeared fairly stable when acoustic detection rates provided a pattern similar to the distribution of satellite-tagged animals averaged over 10 yr (Sveegaard et al 2011b).…”

Section: Seasonal Occurrence and Trends In Harbour Porpoise Presencementioning

confidence: 65%

“…Only 2 previous studies of satellite-tagged harbour porpoises were able to show seasonal movements, possibly also linked to changes in prey distribution (Read & Westgate 1997, Sveegaard et al 2012a. Sveegaard et al (2011a, p. 241-242) emphasized, however, that the observed seasonal movement patterns were not temporally coordinated migrations, but rather 'a seasonal change in im portance of some […] areas' and 'a gradual overall movement over a longer period'.…”

Section: Seasonal Occurrence and Trends In Harbour Porpoise Presencementioning

confidence: 95%

See 1 more Smart Citation

Baltic Sea harbour porpoise populations: status and conservation needs derived from recent survey results

Benke¹,

Bräger²,

Dähne³

et al. 2014

Mar. Ecol. Prog. Ser.

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During recent decades, the 2 distinct harbour porpoise populations of the Baltic Sea have decreased sharply in abundance. The Baltic Proper population is down to a few hundred individuals and is regarded as 'Critically Endangered' by IUCN; the more abundant Belt Sea population also appears to have experienced a severe decline. We summarize the results of extensive static acoustic monitoring in the German part of the Baltic Sea and compare them to published results of aerial and acoustic surveys. Acoustic monitoring confirmed seasonal changes in detection rates consistent with proposed east -west migrations. Detection rates, and thus presumably porpoise density, decrease from west to east from a long-term mean ( in Kadet Trench to 4.4% DPD mo −1 in Pomeranian Bay as one crosses the putative population boundary. Acoustic monitoring results show a recent increase in porpoise registration rates in the Kadet Trench and in Pomeranian Bay, although this does not necessarily indicate a population increase. This large dataset supports the previously suggested proposition that each population uses the boundary waters in Pomeranian Bay alternately, leading to the presence of registration peaks in (late) summer by Belt Sea porpoises, and in winter by Baltic Proper animals. The critical status of porpoises in the Baltic Sea highlights the urgent need for protective measures which still await national and international implementation.

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Section: Seasonal Occurrence and Trends In Harbour Porpoise Presencementioning

confidence: 65%

Section: Seasonal Occurrence and Trends In Harbour Porpoise Presencementioning

confidence: 95%

Baltic Sea harbour porpoise populations: status and conservation needs derived from recent survey results

Benke¹,

Bräger²,

Dähne³

et al. 2014

Mar. Ecol. Prog. Ser.

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“…In particular, it is suggested that a relatively higher abundance of harbour porpoise in spring and summer can be expected in the central North sea, due to seasonal porpoise population movement from coastal areas to offshore areas (Gilles et al, 2009(Gilles et al, , 2016. Such seasonality in occurrence of marine mammals close to O&G platforms could be natural, and reflect a change in prey availability (De Boer, 2010;Sveegaard et al, 2012;Fujii, 2015;Gilles et al, 2016). On the other hand, the combined effect of shorter days and harsher weather conditions significantly reduces the likelihood of detecting marine mammals based on visual surveys (Clarke, 1982;Teilmann, 2003).…”

Section: Discussionmentioning

confidence: 99%

Marine mammal sightings around oil and gas installations in the central North Sea

Delefosse

Rahbek²,

Roesen³

et al. 2017

J. Mar. Biol. Ass.

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Relatively little is known about the distribution and diversity of marine mammals around offshore anthropogenic structures. We present results obtained from incidental sightings of marine mammals around oil and gas installations located 200 km off the Danish coast. A total of 131 sightings corresponding to about 288 animals were reported between May 2013 and May 2016. A total of seven marine mammal species were identified, five cetaceans: harbour porpoise (Phocoena phocoena), minke whale (Balaenoptera acutorostrata), white-beaked dolphin (Lagenorhynchus albirostris), killer whale (Orcinus orca), pilot whales (Globicephala spp.) and two species of pinnipeds: harbour (Phoca vitulina) and grey seals (Halichoerus grypus). The most sighted species were harbour porpoise (41%) and minke whale (31%). Relative counts and biodiversity of marine mammals observed around installations corresponded well with the expected distribution in the central North Sea. Several taxon-specific correlations were identified between number of sightings and environmental parameters (depth and latitude) or installation characteristics (installation aerial footprint). Furthermore, 85% of sightings were made during spring and summer and it is unclear whether the pattern observed reflected a natural seasonal occurrence of marine mammals in the area or an effect of reduced effort during autumn and winter. Despite the potential caveats, results obtained during this programme provide an insight into the relationship between marine mammals and oil and gas offshore installations in the North Sea.

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“…Specifically, changes in water temperature and chemical composition, as well as reproductive state and food availability, may influence the lipid and protein composition of prey, thereby shifting the energetic cost-benefit of that particular prey item (Di Beneditto et al, 2009;Spitz and Jouma'a, 2013). In the Baltic Sea, herring (Clupea harengus) have been shown to increase their energy density by up to 250% between seasons (Sveegaard et al, 2012). The energy density of prey can change at the ecosystem level as well as high quality species being removed by human or climatic pressures and replaced by lower quality species (Spitz and Jouma'a, 2013).…”

Section: Seasonal Energy Content and Prey Qualitymentioning

confidence: 99%

Dolphin Prey Availability and Calorific Value in an Estuarine and Coastal Environment

2016

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Prey density has long been associated with prey profitability for a predator, but prey quality has seldom been quantified. We assessed the potential prey availability and calorific value for Indo-Pacific bottlenose dolphins (Tursiops aduncus) in an estuarine and coastal environment of temperate south-western Australia. Fish were sampled using three methods (21.5 m beach seine, multi-mesh gillnet, and fish traps), across three regions (Estuary, Bay, and Ocean) in the study area. The total biomass and numbers of all species and those of potential dolphin prey were determined in austral summers and winters between 2007 and 2010. The calorific value of 19 species was determined by bomb calorimetry. The aim of the research was to evaluate the significance of prey availability in explaining the higher abundance of dolphins in the region in summer vs. winter across years. A higher abundance of prey was captured in the summer (mean of two summer seasons 12,080 ± 160) than in the winter (mean of two winter seasons = 7358 ± 343) using the same number of gear sets in each season and year. In contrast, higher biomass and higher energy rich prey were captured during winters than during summers, when fewer dolphins are present in the area. Variability was significant between season and region for the gillnet (p < 0.01), and seine (p < 0.01). The interaction of season and region was also significant for the calorific content captured by the traps (p < 0.03), and between the seasons for biomass of the trap catch (p < 0.02). The dolphin mother and calf pairs that remain in the Estuary and Bay year round may be sustained by the higher quality, and generally larger, if lesser abundant, prey in the winter months. Furthermore, factors such as predator avoidance and mating opportunities are likely to influence patterns of local dolphin abundance. This study provides insights into the complex dynamics of predator-prey interactions, and highlights the importance for a better understanding of prey abundance, distribution and calorific content in explaining the spatial ecology of large apex predators.

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Correlation between the seasonal distribution of harbour porpoises and their prey in the Sound, Baltic Sea

Cited by 55 publications

References 36 publications

Baltic Sea harbour porpoise populations: status and conservation needs derived from recent survey results

Baltic Sea harbour porpoise populations: status and conservation needs derived from recent survey results

Marine mammal sightings around oil and gas installations in the central North Sea

Dolphin Prey Availability and Calorific Value in an Estuarine and Coastal Environment

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