by Connie Sullivan, Soundkeeper Science and Education Coordinator
Have you ever seen a fishing vessel going by you while you’re on the ferry in Puget Sound? Have you ever wondered what they were doing, or how they were doing it? Well contrary to what you might be thinking, they may not even be fishing—at least not with the classical endpoint in mind! They could actually be out there doing critical research to track the health and recovery of Puget Sound.
And that ferry wake behind you? Makes for a rocking good time while doing all that work!
In 1989, the Washington Department of Fish and Wildlife began a sampling program for English sole as an indicator of toxics in Puget Sound. These data are used by the Puget Sound Partnership to track the recovery of Puget Sound via their Vital Signs Indicators. English sole are bottom-dwelling fish that don’t migrate too far from one spot, so they are ideal study organisms to get a handle on localized pollution. And because the sole live close to contaminated sediment, they can help track the success of cleanup efforts at target sites. On odd years, the Washington Department of Fish and Wildlife (WDFW) and a small army of volunteers get together to sample at 10 stations, collecting 120 fish at each location.
The amount of info collected from each site, and each fish, is staggering. Sixty of the fish collected at each site are frozen for a whole-body contaminant analysis at a later date. The other 60 fish are dissected the day they are collected. Researchers take the following samples from all male fish:
- Blood: analyzed for the presence or absence of the protein vitellogenin. Vitellogenin is a protein typically only found in female fish, but in the presence of estrogenic compounds it can show up in the bloodstream of the male sole. Estrogenic compounds are those that mimic the natural female hormone, estrogen. They can include compounds such as hormones found in birth control pills and industrial surfactants called nonylphenols.
- Bile: analyzed for the presence of Polycyclic Aromatic Hydrocarbons (PAHs). Many of these compounds can cause cancer. They are created from the combustion of fossil fuels such as when driving a car or burning wood, and they also enter the water from creosote-coated dock pilings. Creosote, which contains tar, helps prevent organisms from growing on the pilings but is not healthy for the marine environment.
- Liver: the liver gets split up in three ways.
- One piece is used to look at the presence of vitellogenin at the gene level. Vitellogenin can circulate in the blood for a while after the fish starts producing it; however, at the gene level, its presence is not sustained for very long, so if it is found it indicates a recent exposure to estrogenic compounds.
- Another piece is used for histology, or the study of the microscopic structure of tissues. From this part of the study, researchers can determine if the cells themselves are altered by the presence of contaminants.
- The final piece is used to look at the types of contaminants in the liver. Since the liver is the main way an organism can break down a chemical, they tend to concentrate there.
- Gut contents: yup, this is as gross as it sounds! We want to look at how the fish are getting contaminants in them — through contact with contaminated sediments, or through food.
- Testis: the whole testis is sent off for histology, similar to the liver.
Female fish have all of these analyses performed except for the blood. This is because females will already have vitellogenin in their blood, so demonstrating it is there doesn’t really help with the results. The other exception is that a section of ovary is taken instead of the testis.
Phew! That’s a lot of info from each fish!
I was lucky enough to be able to participate in this year’s survey for the Eagle Harbor, Elliott Bay, and Duwamish River sites.
At the Eagle Harbor site, we were checking out how the sediment cap is holding up. In the early 1990s, the site was declared an EPA Superfund site, and extensive work went into cleaning up the PAHs that were contaminating the site. This work involved lots of direct removal, and ended with putting a layer of clean sediment over the contaminated sediments to form a cap so they PAHs could no longer get into the water column. The fish at this site went from having lots of cancerous lesions on their livers to having very little occurrence of this — so, all in all, a huge success! This year we wanted to confirm that recent work to strengthen the cap was successful. Monitoring efforts of the cap itself revealed that the propeller wash from the ferries was wearing at the cap faster than anticipated, so last year a layer of large rocks was placed over the cap to help keep the cap in place.
The Duwamish River is home to another EPA Superfund site. This clean-up was initiated in 2001 and is still ongoing. It focuses heavily on removing PCBs, which are an industrial lubricant that is persistent in the environment and causes cancer in organisms and is suspected to do the same in humans. Though PCBs were banned in the late 1970s, they don’t break down once in the environment, and there are still some active sources along the Duwamish. As a result, monitoring of the fish in this area is of great interest to researchers.
Elliott Bay has traditionally been a heavily industrial urban bay. Work has been done to clean up the water and sediments, but fish here are still 10 times more likely to have cancerous lesions on their livers than in cleaner areas.
As you can imagine, this sampling effort is massive, and the final results will take a while to run. WDFW provides the results in a summary that compares previous years as soon as the data are ready. Be sure to start checking their website in a few months for updates!
So the next time you’re out there on the ferry, wave a hello to your friendly local fishing boats—not only are they providing the yummy seafood plates that make the PNW famous, they may also be helping out with the recovery of this beautiful place we all call home.
WDFW’s website: http://wdfw.wa.gov/conservation/research/projects/marine_toxics/
Puget Sound Partnership’s Vital Signs: http://www.psp.wa.gov/vitalsigns/
Photos: Connie Sullivan