Krill (Thysanoessa spinifera) Found Washed Up on Beach

Observation by Asia Beder:

There is a bunch of dead krill on the beach across from the Dutch Harbor post office. Shared via "Unusual Marine Life of Alaska" Facebook Group conversation with Erica Lujan

Dean Stockwell, Biologist and Oceanographer at the University of Alaska Fairbanks, writes:

The krill is definitely Thysanoessa spinifera. Typically, a Pacific form but it does come into the Bering Sea.

8/15/19 Update Melissa Good, Marine Advisory Program Agent with Alaska Sea Grant, writes:

As of August 9, 2019 krill species Thysanoessa spinifera continue to wash ashore in Unalaska. The krill were along about a 100-ft section of the beach along the "S - Curves," which us just south of post office beach, near where they were spotted before, on Amaknak Island. There has been a significant number of humpback whales in Unalaska Bay since early July. The whales are often observed just offshore from where the krill have been observed on the beach feeding, breaching, and fin slapping. See attached picture of the krill on the beach.

Comments from LEO Editors:

8/15/19 Update Melissa Good is coordinating with Dean Stockwell to coordinate a sample to be tested for toxins.

This is the second observation LEO has received about krill washed up on the beach. On June 25, 2019, observers found dead krill, fish, and sea birds along the coast of Shishmaref. Samples from the Shishmaref beach were collected for analysis and results are pending and should be available by the end of August 2019. Die-offs of krill have been generally associated with hypoxia (low oxygen) excess sediment suspended in the water column and changes in water temperature.

The krill species Thysanoessa spinifera can be found from the southeastern Bering Sea to mid-Baja California, usually at a depth of 100 meters. These krill play an important ecosystem role, feeding on microplankton and phytoplankton and providing a food source for fish, birds, and whales. Source: Scripps Institution of Oceanography Thysanoessa spinifera Species Profile.