Prey-Related Asphyxiation in Harbor Porpoises (Phocoena phocoena) along the U.S. West Coast: Importance of American Shad (Alosa sapidissima) on Adult Female Harbor Porpoise Mortality

Harbor porpoise (Phocoena phocoena) diets are predominantly comprised of small fish species (<30 cm) and squid. However, predation on larger species (up to 63 cm) occurs, raising the question of increased risk of asphyxiation associated with this behavior. Literature was reviewed and stranding data from 1983 to 2020 from the U.S. West Coast (including California, Oregon and Washington) were searched for cases of prey-related asphyxiation of harbor porpoises and analyzed in relation to age, sex, reproductive status and prey species. Twenty-nine cases were documented. Twenty-seven cases involved large prey; non-native American shad caused the asphyxiation in 87% of the cases where the prey species was identified. The majority (92%) of harbor porpoises were females, and at least 83.3% were pregnant or recently post-partum. Reproductively active females may be more likely to attempt potentially risky behavior in order to compensate for their increased energetic needs. Increasing numbers of non-native American shad may pose a unique danger in this region for harbor porpoises not adapted to deal with the challenges of that prey. This may be a cause for concern, as there is likely an interaction between location, age and reproductive status on the diet composition and foraging strategies of harbor porpoises.

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Harbor Porpoises (Phocoena phocoena vomerina) Catching and Handling Large Fish on the U.S. West Coast

Aquatic Mammals ◽

10.1578/am.46.2.2020.191 ◽

2020 ◽

Vol 46 (2) ◽

pp. 191-199 ◽

Cited By ~ 1

Author(s):

Cindy R. Elliser ◽

Sanne Hessing ◽

Katrina H. MacIver ◽

Marc A. Webber ◽

William Keener

Keyword(s):

West Coast ◽

Large Fish ◽

Phocoena Phocoena ◽

Harbor Porpoises ◽

The U.S

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Harbor porpoise (Phocoena phocoena) recovery in the inland waters of Washington: estimates of density and abundance from aerial surveys, 2013–2015

Canadian Journal of Zoology ◽

10.1139/cjz-2015-0236 ◽

2016 ◽

Vol 94 (7) ◽

pp. 505-515 ◽

Cited By ~ 3

Author(s):

Thomas A. Jefferson ◽

Mari A. Smultea ◽

Sarah S. Courbis ◽

Gregory S. Campbell

Keyword(s):

Puget Sound ◽

Distance Sampling ◽

Line Transect ◽

Inland Waters ◽

San Juan ◽

Phocoena Phocoena ◽

Harbor Porpoise ◽

San Juan Islands ◽

Juan De Fuca ◽

Harbor Porpoises

The harbor porpoise (Phocoena phocoena (L., 1758)) used to be common in Puget Sound, Washington, but virtually disappeared from these waters by the 1970s. We conducted systematic aerial line-transect surveys (17 237 km total effort) for harbor porpoises, with the goal of estimating density and abundance in the inland waters of Washington State. Surveys in Puget Sound occurred throughout the year from 2013 to 2015, and in the Strait of Juan de Fuca and the San Juan Islands (and some adjacent Canadian waters) in April 2015. We used a high-wing, twin-engine Partenavia airplane and four observers (one on each side of the plane, one looking through a belly port, and one recording data). A total of 1063 harbor porpoise groups were sighted. Density and abundance were estimated using conventional distance sampling methods. Analyses were limited to 447 harbor porpoise groups observed during 5708 km of effort during good sighting conditions suitable for line-transect analysis. Harbor porpoises occurred in all regions of the study area, with highest densities around the San Juan Islands and in northern Puget Sound. Overall, estimated abundance for the Washington Inland Waters stock was 11 233 porpoises (CV = 37%, 95% CI = 9 616 – 13 120). This project clearly demonstrated that harbor porpoises have reoccupied waters of Puget Sound and are present there in all seasons. However, the specific reasons for their initial decline and subsequent recovery remain uncertain.

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Lungworms (Metastrongyloidea: Pseudaliidae) of harbor porpoise Phocoena phocoena (L. 1758)

Canadian Journal of Zoology ◽

10.1139/z75-087 ◽

1975 ◽

Vol 53 (6) ◽

pp. 713-735 ◽

Cited By ~ 22

Author(s):

P. W. Arnold ◽

D. E. Gaskin

Keyword(s):

Host Record ◽

Phocoena Phocoena ◽

Harbor Porpoise ◽

Eastern Canada ◽

New Host ◽

Grampus Griseus ◽

New Host Record ◽

Consistent Treatment ◽

First Time ◽

Harbor Porpoises

Lungworms were collected from 60 harbor porpoises shot at sea during May to August of 1970 and 1971 in the Bay of Fundy. These have been compared with related species from other odontocetes in order to evaluate the literature on pseudaliids and provide a consistent treatment of the family. This study also gives data on the occurrence of lungworms in odontocetes from Canadian waters. Keys to genera and selected species of pseudaliids in cetaceans are included.The following are redescribed: Pseudalius inflexus (Rudolphi 1808), Stenurus minor (Kuhn 1829), Torynurus convolutus (Kuhn 1829), Halocercus invaginatus (Quekett 1841), and H. taurica Delyamure, in Skrjabin 1942 from harbor porpoise, Phocoena phocoena, collected in eastern Canada; Stenurus globicephalae Baylis and Daubney 1925 from Globicephala melaena, G. macrorhyncha, and Grampus griseus (new host record); Stenurus arctomarinus Delyamure and Kleinenberg 1958 and Pharurus pallasii (van Beneden 1870) n. comb, from Delphinapteras leucas; Torynurus dalli (Yamaguti 1951) from Phocoenoides dalli; and Pharurus alatus (Leuck-art 1848) from Monodon monoceros. Pseudalius inflexus, H. taurica, and S. arctomarinus are reported for the first time from North American hosts; S. globicephalae, P. pallasii, P. alatus, and all the pseudaliids from Phocoena phocoena are reported from new host localities.Torynurus alatus is considered a synonym of Pharurus alatus. Stenurus arcticus (including previously proposed synonyms Strongylus arcticus, Pseudalius arcticus) is considered a synonym of Pharurus pallasii.Halocercus ponticus Delyamure 1946 is considered synonymous with H. invaginatus.

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Unusual Mortality Events of Harbor Porpoise Strandings in North Carolina, 1997–2009

Journal of Marine Biology ◽

10.1155/2013/289892 ◽

2013 ◽

Vol 2013 ◽

pp. 1-13 ◽

Cited By ~ 5

Author(s):

Aleta A. Hohn ◽

David S. Rotstein ◽

Barbie L. Byrd

Keyword(s):

North Carolina ◽

Threshold Analysis ◽

Phocoena Phocoena ◽

Harbor Porpoise ◽

Interspecific Aggression ◽

Cape Hatteras ◽

Causes Of Mortality ◽

Young Of The Year ◽

Harbor Porpoises ◽

Secondary Causes

A marked increase in the frequency of harbor porpoises (Phocoena phocoena) stranded in North Carolina in 2005 was declared as an Unusual Mortality Event (UME). Strandings occurred in January through May when harbor porpoises are seasonally present. Increased stranding rates were measured relative to a threshold to determine that the UME was occurring. The threshold analysis also revealed elevated strandings during 1999, an undeclared UME year. Recovered carcasses during 1999 and 2005 accounted for 39% of 261 strandings during 1997–2009. During 2005, of 43 strandings, primary or secondary causes of mortality included fishery interactions, emaciation, and interspecific aggression. Apart from small but significant differences in timing and condition of strandings, composition of strandings during UME and non-UME years was similar, with most being young-of-the-year and occurring during March and April, north of Cape Hatteras. Porpoises had high levels of parasitic infestation typical for this species. However, no indication of infectious disease and no cause of the 2005 event were found from gross and histologic findings. Response to UMEs is challenging, particularly along the expanses of North Carolina beaches, requiring additional effort to obtain carcasses in sufficiently fresh condition to determine the cause of these events.

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