New publication: Micro-scale spatio-temporal patterns in porpoise activity
Dear all, We are pleased to share our new publication: Micro-scale spatial preference and temporal cyclicity linked to foraging in harbour porpoises. Stedt J, Wahlberg M, Carlström J, Nilsson PA, Amundin M, Oskolkov N & Carlsson P. (2023) Mar Ecol Prog Ser, 708:143-161. doi: 10.3354/meps14268 Abstract: Habitat heterogeneity is a crucial driver for species distribution across scales. Harbour porpoise Phocoena phocoena basin-wide distribution is linked to prey availability, and small-scale (kilometres to tens of kilometres) differences in distribution are prevalent. However, information on porpoise distribution and foraging-behaviour variations on a micro-scale (~100 m to kilometres) is limited. To monitor harbour porpoise distribution and foraging activity on a micro-scale, we deployed passive acoustic dataloggers, logging porpoise acoustic activity at 6 sites in a small, high porpoise-density area in southern Sweden. Data were collected for almost a year, giving detailed time series on porpoise activity. The time series were analysed using dynamic time warping to compare activity patterns between sites. Large differences were found between sites separated by only a few hundred meters, indicating micro-scale spatial preference. Spectral analysis for temporal cyclicity in activity revealed a dominant peak for 24 h cycles with higher activity at night for all sites. All sites also had a second peak for 29.5 d, linked to the lunar cycle with higher activity during full moon. Activity was overall highest during autumn and winter (September-December). Spatial and temporal patterns were linked to foraging, showing a positive correlation between porpoise presence and the percent of time present with detected foraging. The study demonstrates that harbour porpoise spatial distribution on a micro-scale should be considered in e.g. behavioural, management and conservation studies and actions. In addition, we show that time series statistical methodology is informative and appropriate for analysis of acoustic temporal data. The paper is open access and can be freely downloaded at: https://www.int-res.com/articles/meps_oa/m708p143.pdf Please feel free to contact me if you have any questions. Best regards, Johanna Stedt Johanna Stedt PhD student Aquatic Ecology Department of Biology Lund University Sölvegatan 37, 223 62 Lund, Sweden Phone + 46 (0)73 738 30 36 E-mail: johanna.stedt@biol.lu.se<mailto:johanna.stedt@biol.lu.se> Personal webpage: Johanna Stedt<https://portal.research.lu.se/portal/en/persons/johanna-stedt(d8f35e4a-cb7e-4720-b11b-02f0215f9d2b).html>
Dear all, We are pleased to share our recent publication on harbour porpoise foraging behaviour in Ecology and Evolution: Stedt, J., Hamel, H., Torres Ortiz, S., Højer Kristensen, J. and Wahlberg, M. (2024), Harbour Porpoises Are Flexible Predators Displaying Context-Dependent Foraging Behaviours. Ecol Evol, 14: e70671. https://doi.org/10.1002/ece3.70671 Abstract: Opportunistic mobile predators can adapt their behaviour to specific foraging scenarios, allowing them to target diverse prey resources. An interesting example is the harbour porpoise (Phocoena phocoena), a marine mammal with a huge energy demand feeding on a large variety of fish, squid and shrimps. Little is known about the foraging behaviour of harbour porpoises, as observations of wild specimens are notoriously difficult to obtain. In this study, foraging was identified in almost 60% of videos from UAV recordings in Danish coastal waters during daylight hours. Observations reveal them to be flexible predators, foraging on both single fish and schools of fish, as well as individually and in groups of varying sizes. We argue that some of the observed behavioural adaptations and context-dependent strategies for prey capture are based on information transfer and social learning. Our results provide unprecedented insights into the foraging behaviour of an opportunistic mammalian predator. Furthermore, this study highlights the importance of porpoises having access to coastal areas for energy acquisition, where they are in conflict with anthropogenic disturbances such as fisheries with the risk of bycatch. The paper is open access and can be freely downloaded at: https://onlinelibrary.wiley.com/doi/10.1002/ece3.70671 Please feel free to contact me if you have any questions. Best regards, Johanna Stedt ______________________________________________________ Johanna Stedt PhD, Researcher Lund University Department of Biology Telephone: +46 (0)73 738 30 36 E-mail: johanna.stedt@biol.lu.se<mailto:johanna.stedt@biol.lu.se> Personal webpage: Johanna Stedt<https://portal.research.lu.se/portal/en/persons/johanna-stedt(d8f35e4a-cb7e-4720-b11b-02f0215f9d2b).html> https://www.biology.lu.se
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Johanna Stedt