Harbour Seals: Population Structure, Status, and Threats in a Rapidly Changing Environment

Abstract

The harbour seal (Phoca vitulina) is the world’s most widely distributed pinniped species ranging from temperate to Arctic regions (30–78.5° N in the Atlantic, 28–61.2° N in the Pacific), but no detailed overview of the species status exists. The aims of this review are to (i) provide current information on the genetic structure, population status, and threats; (ii) review potential consequences of a changing climate; and (iii) identify knowledge gaps to guide future research and monitoring. Although the species is globally abundant, wide differences exist across the species’ broad range. As climate warms, populations at the edges of the species’ distributional range are likely to be more affected. The primary climate-related drivers include: (i) changes in weather patterns, which can affect thermoregulation; (ii) decrease in availability of haul-out substrates; (iii) large-scale changes in prey availability and inter-specific competition; (iv) shifts in the range of pathogens; (v) increase in temperature favouring the biotransformation of contaminants; and (vi) increased exposure to pollutant from increased freshwater run-off. Multiple anthropogenic stressors may collectively impact some populations. Coordinated monitoring efforts across and within regions is needed. This would allow for a spatially explicit management approach including population-specific responses to known stressors.

Hepatic Fatty Acid Profiles Associated with Exposure to Emerging and Legacy Halogenated Contaminants in Two Harbor Seal Populations across the North Atlantic

“…This species is currently listed as “Least Concern” in the International Union for the Conservation of Nature red list . However, concern has been raised over the threats to regional populations posed by various factors including climate change, human disturbance, and pollution, so coordinated monitoring efforts across and within regions are desired . In the present study, we provided a timely investigation on the hepatic FA profiles and contamination levels of a suite of legacy and emerging halogenated contaminants in harbor seals from the Gulf of Maine and the south coast of Sweden.…”

“…71 However, concern has been raised over the threats to regional populations posed by various factors including climate change, human disturbance, and pollution, so coordinated monitoring efforts across and within regions are desired. 72 In the present study, we provided a timely investigation on the hepatic FA profiles and contamination levels of a suite of legacy and emerging halogenated contaminants in harbor seals from the Gulf of Maine and the south coast of Sweden. Given that both populations inhabit coastal areas close to large human populations, the comparative examination of foraging ecology and contaminant status will have important implications for both conservation and biomonitoring.…”

First Report of Uncinaria hamiltoni in Orphan Eastern Mediterranean Monk Seal Pups in Greece and Its Clinical Significance

“…On the other hand, when dispersal is not local, parasites invest in an intermediate dispersal distance through selective pressure on the spatial dynamics of host-parasite interaction [49]. However, this co-evolutionary characteristic of dispersal may be due to environmental pressures, such as climate change or more direct anthropogenic impacts [50], or possibly due to species-level potential mechanics behind transmission and intermediate hosts [51].…”

Deciphering Eurasian otter (Lutra lutra L.) and seal (Phoca vitulina L.; Halichoerus grypus F.) diet: Metabarcoding tailored for fresh and saltwater fish species

“…Both seal species have noted a positive population trend in the German Bight over the last decades but are threatened by multiple anthropogenic stressors. Seals and otters have experienced population declines as a result of hunting, habitat loss, as well as exposure to contaminants such as organochlorines, dieldrin, DDT/DDE and polychlorinated biphenyls in the last century (Blanchet et al, 2021; Conroy et al, 2000; Kovacs et al, 2012). In addition, the North Sea harbour seal population suffered from two epidemics caused by phocine distemper virus in 1988 and 2002 (Härkönen et al, 2006) and one caused by influenza A virus, serotype H7N10 (Bodewes et al, 2015) whereas otters are vulnerable to road kills during migration for food (Duplaix & Savage, 2018).…”