MASSIVE DUNGENESS CRAB DIE OFF

On 11/05 Clam Diggers Association member Jerry Lynch reported thousands of Dungeness crabs washed ashore at the southern section of beach at Seaside. His report follows:

Bill, I’m writing to give you a clamming report from Wednesday 11/04, 7:38 pm low tide from South Seaside Beach.
1. Damn dark, even with the Coleman Northstar lantern on “high”, because the wind keeps blowing it to “dim”.
2. The wind has come up from “nothing” at dusk, to steady 50mph NNE. It is almost hard to stand up, and if not braced properly with shovel the lantern will blow over when set down on the sand so as to free my hands in order to “gun” a clam.
3. The beach is covered with large dead crabs. Most are legal size, some are HUGE as dinner plates. All are dead. I am not saying 100’s, I am saying thousands. THOUSANDS.
My suspicion is that the “dead zone” of zero oxygen is the culprit. I wonder at the eventual impact on the commercial crab fisherman…
4. The clams are showing with the help of a little shovel banging, so I manage to scratch out my 15 and get the hell out off of the beach before the winds get worse…-Jerry Lynch

If I recall ODFW biologist, Dale Snow’s publication “Where Have All the Crabs Gone?” correctly, he describe the carapace from thousands of crabs that molted and washed ashore onto Oregon’s Beaches. Jerry’s report of thousands of dead Dungeness crabs is not to be confused with the carapace from molted Dungeness crabs. As always good digging, Bill

Matt Hunter the ODFW Shellfish Project Leader from the ODFW Astoria office provided a timely answers to Jerry Lynch’s observation with the following,

“Bill,  We noticed a fair number of crab on the southern Clatsop beaches on Monday.  Upon inspection they were not molts as they still had meat within the legs and carapace.  These were very large crab, easily the commercial size limit or larger.  If I was to hypothesize to their demise it would either be senescence or asphyxiation from the protein surfactants (mucilage) caused by the Akashiwo sanguinea bloom that we have had off the north Oregon coast.  There are laboratory reports that indicated that oysters and mussels are impacted by large amounts of surfactants in the water.  It interrupts the respiration process by hindering the flow of water through the gills thus asphyxiation.  We will keep an eye out but it won’t be until after the storm surge has ebbed.  Matt”

Matt Hunter and staff investigated the crab die off and emailed his their findings.  We thank Matt and his staff for their immediate response to our inquiry.

Bill, Upon revisiting the data and visual accounts from my assistant we believe that the number of crab we saw on Monday was less than 50 for a 14 mile stretch of Clatsop beach.  We went out today and drove a 15 mile stretch, including Seaside, and did not see a single crab.  At this point it is difficult if not impossible to determine what if any event occurred. Matt