Fishing for Science

Seems too good to be true!

A perfect example of fishing for science! We then dissected the salmon, of course salvaging some nice fillets for eating.

A perfect example of fishing for science! We then dissected the salmon, of course salvaging some nice fillets for eating.

About a week ago I left Coyahique on a plane to Puerto Montt. There I was greeted by Andres Olivos, a Chilean PhD student going to Oregon State University. Together we drove to the Rio Puelo area. I found myself in the middle of a beautiful jungle with rivers in all directions. It was truly a fisher(wo)man’s wonderland.

In my next post I will report an interview with Andres Olivos, so I won’t get to into the nitty gritty about his research right now. But some general knowledge is helpful. Living beings are always shedding cells (for instance we are always shedding skin cells) and fish do the same. There shedded cells flow through the water and that DNA from the cells is called environmental DNA. Our mission was to extract that DNA for further research. We did this by pumping water through very fine filters that collect the DNA.

From each river we took 4, one liter samples of water and pumped them each through their own filter. Here is a timelapse of me filtering the water, extracting the DNA, and preserving it in alcohol (a good DNA preserving agent).

On the first day we sampled and fished the Petrohue river and some of its tributaries. I was taught the sampling techniques and was able to start helping immediately. In addition, we took notes on each rivers depth and width, surrounding terrain and foliage, and GPS location.

Soon we made our way to the Rio Puelo. There we got to go fishing and sampling from a boat.

We were driven by a local man named Carlos on his little boat. The river was winding with many tributaries stemming out of the main current. The views were stunning. I fly fished for a bit and then switched to using a gear rod and trolling. That is when I hooked into the big Chinook Salmon of about 10 kilograms.

We dissected the salmon that I caught, of course salvaging fillets for dinner. We sent the stomach, muscle, liver and the axillary process above the pelvic fin into a lab here in Chile for further research. I have always been curious about fish, especially salmon and trout, and on this trip I finally got some of my questions answered! Again I will dive more into that on my next post.

The rest of the days we sampled more rivers and fly fished for trout for another line of research being done here in Chile. I still can’t get over it… fishing for science! Really it is the most amazing thing. We did have to kill the fish because they would be used for DNA tests and needed to be brought to the laboratory. This led us to talk about some ethics of fishing.

Most of my fly fishing has been catch and release and I felt odd killing these small trout. I definitely have a soft spot for these cute little critters. Andres Olivos explained to me that neither salmon nor trout are native to Patagonia. They were all introduced to start a fishing industry here in the South. This made me feel a bit better about killing these precious animals. Plus we only killed a few a day.

The Office :)

The Office :)

The fishing was a total blast. There are tons of small trout in the area making the fishing relatively easy. We were on the hunt for brook trout, but only found rainbow and brown. Hopefully Andres will find the brook trout stash soon!

Then we took the small trout back to the house to remove the axillary process above the pelvic fin. The meat attaching the fin to the body is extremely dense in DNA so it is a good tool for scientist. We also packaged up the fish to be sent to a university here in Chile for more research.

It has been a blast to work with Andres in Rio Puelo. I am excited to share with you an interview explaining more of his research and why it is so important. More to come soon!