Postmortaal onderzoek van bruinvissen (Phocoena phocoena) uit Nederlandse wateren, 2016

IJsseldijk, Lonneke L.; Kik, Marja; Solé, L.; Gröne, Andrea

doi:10.18174/418563

Cited by 2 publications

(1 citation statement)

References 7 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Obviously, there may be combinations of factors involved, and pinpointing one cause is not always possible (Mazzariol et al, 2011;IJsseldijk et al, 2018d). In The Netherlands, postmortem examinations on stranded marine mammals have been conducted since (IJsseldijk et al, 2018b. Databases hold information on causes of death, their physical condition, disease burden and nutritional condition.…”

Section: Implications For Conservation and Managementmentioning

confidence: 99%

Predicting Harbor Porpoise Strandings Based on Near-Shore Sightings Indicates Elevated Temporal Mortality Rates

et al. 2021

View full text Add to dashboard Cite

The increase in anthropogenic activities and their potential impact on wildlife requires the establishment of monitoring programs and identification of indicator species. Within marine habitats, marine mammals are often used as ecosystem sentinels, which has led to investigations into their abundance, distribution, and mortality patterns. However, trends in sightings and strandings are rarely analyzed in combination. This is necessary to distinguish elevated stranding rates caused by changes in local abundance from increased mortality as a consequence of other natural, environmental or anthropogenic factors. Therefore, the objective of this study was to assess whether harbor porpoise (Phocoena phocoena) stranding frequency in the southern North Sea can be explained by local population density derived from more than 400 thousand hours of systematic observations along the Dutch coast between 1990 and 2018. Since the late 1990s, both the number of stranded porpoises and the sighting rate increased rapidly up to around the mid-2000s, after which they remained high, but with large inter-annual fluctuations. On an annual basis there was a strong correlation between porpoise strandings and sightings, but with a seasonal mismatch. Highest stranding rates occur in late summer, while highest sighting rates occur in early spring. Despite low sighting rates in late summer, August appears to be the best predictor for the monthly variation in the number of stranded porpoises, which could be explained by post-reproductive dispersal and mortality. Excessive high porpoise stranding numbers after accounting for variations in local density could signpost unusual mortality events (UMEs). The corrected stranding rates show that in the early 1990s, when porpoise sightings were rare, and after 2010, the number of stranded porpoises exceeds the expected number. Especially in the summer of 2011, the number of dead porpoises found ashore was excessively high and this might reflect an UME. These results demonstrate that a comparative interpretation of marine mammal strandings and coastal sightings can be a valuable management and conservation tool that could provide an early warning signal for population change.

show abstract

Section: Implications For Conservation and Managementmentioning

confidence: 99%

Predicting Harbor Porpoise Strandings Based on Near-Shore Sightings Indicates Elevated Temporal Mortality Rates

et al. 2021

View full text Add to dashboard Cite

show abstract

Harbour porpoise (Phocoena phocoena) in the Wadden Sea World Heritage Site and requirements for trilateral monitoring

Scheidat,

Vrooman,

Teilmann

et al. 2024

Mar. Biodivers.

View full text Add to dashboard Cite

The harbour porpoise (Phocoena phocoena) is considered part of the ‘Outstanding Universal Value’ characterising the Wadden Sea World Heritage Site (WS WHS). The Trilateral Wadden Sea Plan aims to preserve the conservation status of the Trilateral Wadden Sea Cooperation Area, encompassing the WS WHS. The plan has specified two conservation targets for the harbour porpoise: (1) viable stocks and a natural reproduction capacity and (2) conservation of habitat quality for its conservation. To assess the current occurrence of the harbour porpoise in the Wadden Sea area, we collated and analysed data from regional and national research projects using telemetry, aerial surveys, strandings and passive acoustic monitoring, obtained over the years 1990–2020. The results illustrate that porpoises occur in both offshore and intertidal waters, showing seasonal movements and changes in local occurrence over time. Some porpoises displayed limited home ranges throughout the year, suggesting a possible residency for some of the animals using the Wadden Sea area. We also showed that methods, frequency and spatial coverage of monitoring activities vary among the countries Denmark, Germany and the Netherlands. We discuss the suitability of the different methods both regarding the challenges of monitoring in the complex Wadden Sea habitat as well as their ability to target the conservation aims of the WHS. We give several recommendations to assess the status of the species to meet the identified conservation aims.

show abstract

Postmortaal onderzoek van bruinvissen (Phocoena phocoena) uit Nederlandse wateren, 2016

Cited by 2 publications

References 7 publications

Predicting Harbor Porpoise Strandings Based on Near-Shore Sightings Indicates Elevated Temporal Mortality Rates

Predicting Harbor Porpoise Strandings Based on Near-Shore Sightings Indicates Elevated Temporal Mortality Rates

Harbour porpoise (Phocoena phocoena) in the Wadden Sea World Heritage Site and requirements for trilateral monitoring

Contact Info

Product

Resources

About