'Killer' seaweed attacks
June 25, 2008 · Updated 4:45 PM
A localized fish kill in the west end of Penn Cove last weekend was probably caused by Whidbey's hot, dry summer, not manmade pollution. Last Saturday morning, homeowners woke to a disquieting sight.
"Fish were beaching themselves, jumping and gasping for oxygen," Good Beach Road resident Larry Richards said.
At low tide, carcasses of "thousands of small fish" covered the rocks he said.
WSU/Island County Beach Watcher Jan Holmes investigated the environmental incident. She collected bodies of several fish and some small octopus. In a report she filed with Beach Watchers, Holmes reported that a sea lettuce, or ulva, bloom in Penn Cove smothered the fish.
"Ulva floats, it doesn't attach like other seaweed species," Holmes said. "It's common to see great rafts of it floating."
Holmes surmised recent hot, still weather started the floating ulva on a growth spurt. When the short- lived organism begin to die, bacteria depleted Penn Cove's water of oxygen. Eelpouts and other species are susceptible to oxygen level fluctuations.
"Luckily, as the tide started coming in, life seemed to perk up," Holmes said. Water moving in from deeper areas of the cove would be cooler, she said, and also movement would carry more oxygen.