Fisheries symposium recaps research

How are climate change and chemicals introduced into the water system affecting species such as eelgrass, salmon and orca whales?

Dozens of researchers participated in a two-day science symposium held by the Northwest Fisheries Science Center in Seattle this week to discuss those types of questions.

The Northwest Fisheries Science Center is one of six regional science centers operated by National Oceanic and Atmospheric Administration Fisheries. This week’s event was the center’s fifth annual symposium.

Researchers who presented their work discussed topics such as ocean acidification and how climate change may impact marine species.

Ocean acidification, which occurs when a high concentration of carbon dioxide in the water lowers the pH, is harmful to species such as zooplankton.

Research ecologist Paul McElhany said he found during a study at the Northwest Fisheries Science Center’s Mukilteo lab that zooplankton have a lower survival rate in water with a lower pH.

More work is needed to understand how that will impact the larger food web, which includes invertebrates, fish, whales, mammals, birds and humans, McElhany said.

NOAA Ocean Acidification Program Director Libby Jewett said research such as McElhany’s is important because ocean acidity is expected to increase by up to 150 percent by 2100 as a result of carbon dioxide emissions from burning fossil fuels.

Researchers at the symposium also described recent work involving sea grasses, salmon and orcas.

The state Department of Natural Resources recently announced that eelgrass in Puget Sound is increasing its coverage.

That’s good news, particularly for the species that live in eelgrass meadows.

During the symposium, Ole Shelton of the Northwest Fisheries Science Center said it’s also good news that eelgrass is showing growth despite poor water quality in Puget Sound.

NOAA zoologist Lyndal Johnson and University of Washington graduate student Louisa Harding described how poor water quality can be bad for salmon.

Johnson’s research involving pollutants found in juvenile chinook salmon has shown that over the past 25 years the concentration of some chemicals in Puget Sound salmon has declined, but they are still present.

The good news is that of five Puget Sound rivers included in a recent study, fish from the Skagit River showed the lowest concentration of harmful chemicals, according to Johnson’s presentation.

Chemicals found in wastewater from homes, industries and stormwater systems can affect fish reproduction, according to Harding’s research. Some chemicals can replicate the hormone estrogen, causing abnormalities in the reproductive organs of juvenile coho salmon.

Some chemicals found in salmon are also found in orcas, which has prompted concern over the recovery of the endangered southern resident orca population. Orcas typically feed on chinook salmon.