Harbor Porpoise
Whale Tales: cetacean stranding and medicine in the Pacific Northwest
Harbor Porpoise Stranding Research
In 2006–2007, an unusually high number of harbor porpoises (Phocoena phocoena) stranded along the Washington and Oregon coastlines.
Spatiotemporal analyses were used to examine their ability to detect clusters of porpoise strandings during an unusual mortality event (UME) in the Pacific Northwest using stranding location data.
Strandings were evaluated as two separate populations, outer coast and inland waters. The presence of global clustering was evaluated using the Knox spatiotem- poral test, and the presence of local clusters was investigated using a spatiotemporal scan statistic (space–time permutation). There was evidence of global clustering, but no local clustering, supporting the hypothesis that strandings were due to more varied etiologies instead of localized causes.
Further analyses at subregional levels, and concurrently assessing environmental factors, might reveal additional geographic distribution patterns. This article describes the spatial analytical tools applied in this study and how they can help elucidate the spatiotemporal epidemi- ology of other UMEs and assist in determining their causes. More than one spatial analytical technique should be used if the study objective is to detect and describe clustering in time and space and to generate hypotheses regarding causation of marine mammal disease and stranding events.
SeaDoc's Joe Gaydos is a co-author on the paper. Find it at http://www.seadocsociety.org/node/606
The application of GIS and spatiotemporal analyses to investigations of unusual marine mammal strandings and mortality events
Birds and Mammals that Depend on the Salish Sea: A Compilation
Hybrid Porpoise Necropsy
Today SeaDoc and the Whale Museum did a necropsy (the word for animal autopsy, think Wildlife CSI) on a porpoise.
Check out the picture and you'll see its not really a Dall's porpoise nor is it a Harbor porpoise. That's because its a cross. This animal was born from a Dall's porpoise mother and a Harbor porpoise father.
Even though natural hybridization is rare in mammals, these crosses have been seen in the Salish Sea for over a decade now.
What was interesting today is that this female was pregnant, showing that the Dall's / Harbor porpoise hybrids are fertile. The near-term fetus was colored much like a harbor porpoise.
The necropsy did not reveal the cause of death for this porpoise, but further tests are pending.
To learn more about marine mammals, visit the Whale Museum's website at http://www.whale-museum.org/
Update: View photos from the entire necropsy at Adam U's website. Warning: the pictures are gory. But cool.
http://adamcu.com/hybrid-porpoise-necropsy-warning-gory-photos
Killer whales kill and then abandon a harbor porpoise off San Juan Island
On September 9, 2009, researchers who were tracking southern resident killer whales in Haro Strait noticed whales from J- and K-pods interacting with a harbor porpoise.
Three specific whales (J31, J36 and J39) spent the most of the time with the porpoise and J-31 was seen using its head to throw the harbor porpoise in air on two occasions. The entire interaction lasted over 30 minutes.
.thumbnail.jpg "Harbor porpoise killed by southern resident killer whales")
Species of concern within the Salish Sea Marine Ecosystem: changes between 2002 and 2008
Multidisciplinary investigation of stranded harbor porpoises (Phocoena phocoena) in Washington State with an assessment of acoustic trauma as a contributory factor (2 May - 2 June 2003)
Does Bycatch Threaten Dolphins and Porpoises?
A recent SeaDoc Society-funded project found that salmon gill net fisheries could pose a threat to populations of harbor and Dall’s porpoise but not Pacific white-sided dolphin in British Columbia. Regional salmon gillnet fisheries accidentally catch and kill dolphins and porpoises and it is critical to know when such bycatch threatens these cetacean populations so that protective actions can be taken.
