A hybrid porpoise stranding….

This hybrid porpoise was discovered washed up on the beach near American Camp...

If you’ve been out on the water much around here, you know there’s harbor porpoises & Dall’s porpoises…when they interbreed, they have hybrid kids. Here’s more about one that turned up on the beach here, in a report from Amy Traxler of the Marine Stranding Network, with a reminder to let her know about any animal – alive or dead – that you find washed up:

The dead porpoise was in the third trimester; this is the fetus she was carrying.

On May 21, the San Juan County Marine Mammal Stranding Network (SJCMMSN) received a call from the National Park Service of a dead porpoise on one of their pocket beaches at American  Camp.  Upon investigation, it turned out to be a female hybrid porpoise in excellent condition.   The carcass was recovered, brought to the Friday Harbor Labs, and necropsied by Joe Gaydos on Monday morning. Although the necropsy didn’t reveal any obvious cause(s) of death, additional testing is underway.  She was carrying a third-trimester fetus.

Hybrid porpoise – crosses between Dall’s and harbor – have been documented in the Salish Sea, British Columbia, and southeast Alaska for many years.  They appear to be offspring of a Dall’s female and a male harbor porpoise and, therefore, are found traveling with Dall’s porpoise.

Amy Traxler, coordinator of the SJCMMSN, says:  “This was an incredible find!  As far as I know, we’ve never recovered a hybrid porpoise here in San Juan County and, although we’re still searching the literature and contacting other researchers, we believe this may be the first pregnant hybrid porpoise that has ever stranded.” Further testing on this porpoise will be conducted including genetic testing on both mom and fetus, as well as skeleton comparisons to both species of porpoise.

As always, please contact the Stranding Network  at 1-800-562-8832 whenever you find a marine mammal – live or dead – on shore.

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