Hood Canal's hypoxic state has had devastating effects on the sub-basin's biodiversity. Valuable commercial species such as geoduck clam and Dungeness crab may be adversely affected by hypoxic conditions. Critically low oxygen levels, due to increased bacterial growth, were observed in the lower portion of Hood Canal during the summer months of 2004 and 2005. A low dissolved oxygen content in Anna's Bay and Lynch Cove is believed to have been responsible for the corresponding decline in spot shrimp catch by Skokomish Nation fishers within the same period of time. In 2010, there was a massive fish kill in the southern part of Hood Canal. Hundreds of fish and thousands of shrimp were found washed up onto the shore. Jan Newton, a local oceanographer, concluded that the water contained less than 1 milliliter per liter of dissolved oxygen and that such a low level is extremely stressful, often lethal, to the marine life in Hood Canal. The effects of Hood Canal's hypoxic conditions are clearly seen by the public through massive fish kills, but it is important to identify other harmful impacts resulting from a lack of oxygen in the basin. Eelgrass beds, which are nurseries for salmon and crab, have declined more in Hood Canal than any other area of the Puget Sound. Bottom dwelling rockfish have also seen a decline due to a lack of eelgrass. Other notable cases of hypoxia and its adverse effects on biodiversity include the large-scale hypoxic zone that appears in the Gulf of Mexico each summer.