Effects of coastal ‘dead zone’ unclear |
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| August 29, 2006 | |||
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The discovery of the dead zone coincided with a fish kill at Point Grenville on the Quinault Indian Reservation, where dead fish washed ashore, including several deep-water species. “This is the first time that many members can remember those kinds of fish washing up,” said Debbie Preston, spokeswoman for the Northwest Indian Fisheries Commission. “The tribe is very concerned and it’s definitely something that they’re monitoring.” The “dead zone” has appeared off the Oregon coast for five years in a row, but according to Mary Sue Brancato of the Olympic Coast National Marine Sanctuary, this is the first year that area scientists have detected it this far north. Scientists are now taking continuous readings of the coast’s oxygen levels. “Because we’ve only been taking oxygen level readings for a year, it’s not definitive that this is a new occurrence at all,” Preston said. “We don’t really know what’s ‘usual.’ But the Quinaults haven’t had anything like this in their history.” The Quinaults didn’t need any oxygen-level monitoring to find out that something strange was happening off the coast. The fish kill at Point Grenville was all the evidence they needed. Additional state Fish & Wilfdlife reports of pots filled with dead crab and strange fish washing ashore are fueling the speculation that these low oxygen levels could threaten both private and tribal fishing and crabbing. Ed Johnstone, spokesman for Quinault Nation Fisheries, is waiting for more data from coastal scientists.
“I don’t know that anybody can conclusively answer all the questions we have,” he said. “We’re working with scientists to try to figure out what is causing the low-oxygen levels, but we just don’t know if this will have any significant impact on fish and crab populations. “Populations are volatile for many other reasons, so even if we don’t have a good year, we won’t even know if it’s because of the dead zone,” he said. Heather Reed of Fish & Wildlife agreed with Johnstone, saying “The information we get on populations is from the harvest levels, and so many things contribute to high and low abundance. I guess we’ll find out in December when crab season starts again.” Reed believes it is still unclear whether the low oxygen levels known as hypoxia are a new phenomenon for Washington waters. “I’ve heard of similar events like this in the past, and I don’t know if this time it’s just getting more press because we’ve been able to do more monitoring,” she said. Johnstone said that the debate is still raging over the science behind the low oxygen levels. Pollution was suspected at first, because runoff was found to play a role in forming dead zones that appeared in Gulf of Texas and Hood Canal in the past. But coastal scientists have ruled out pollution in this case. Researchers at Oregon State University have isolated the wind-driven process of “upwelling” as the culprit. Upwelling is a natural process that brings deep, nutrient-rich waters back up to the shallow parts of the ocean. But these deeper waters are naturally low in oxygen, and any fluctuation in the process could upset the balance that marine life depends on. Changes in wind patterns can cause highs and lows in the upwelling process. During the calmer periods, plankton and other small plant species reproduce heavily and then die. The decomposition process removes oxygen from the water. The Oregon State University research also suggested that global warming might be behind these wind shifts. As scientists continue to debate the cause of the dead zone, those dependent on fish and crab for their livelihood can only wait for more information. “It’ll take quite a bit of time to try to connect the dots between population and hypoxia,” Preston said. “We don’t know if this will have a significant impact on populations, but until we find out, we’ve got our finger on the pulse,” Johnstone said. Jordan Kline, a Daily World writer, can be reached at 532-4000 ext. 111 or jkline@thedailyworld.com. |
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