Friday, August 13, 2010

Laury - Surf Zone Sampling!

Hello fellow bloggers! As promised I am going to talk to you a little bit about how we collect all of our samples. The primary focus of these outdoor adventures is to catch salmon out in the surf, but we also want to collect the prey that salmon eat. How do I know what salmon eat? Well Jose (my mentor) has been doing this study for 5 years now, and part of what he does when he catches salmon is conduct a stomach analysis. Basically he looks at all of the stomachs of the salmon that’s been caught and identifies what they’ve been eating. So far the main prey species seem to be mysids, amphipods, megalopae and other juvenile fish, or their fish larvae.
How do we sample? Well there are a couple different ways that we collect our samples. First is the “seining method” which is a 15 meter long mesh net. Three people carry the net from the shore to the surf and then once we reach a deep enough spot the middle person stakes the middle pole into the ground and the other two people with poles stretch out the net to form a “V” shape. Once we know the net is not tangled up we drag the net across the sea floor and back to shore. We are literally scooping up all of the inhabitants of the surf in the net and bringing them back to shore.
Once the net is dragged up on shore, we extend out the net and collect everything that we’ve caught. We count everything we found and record that in a little handy dandy notebook, and everything is returned back to the water with the exception of salmon or shrimp, or other species of prey that the salmon eat for “bombing” later. Some of the cool things we have found by doing this are: starry flounders, staghorn sculpins (grumpy little guys), English sole, pike fish (look similar to a seahorses), gooseberries, jellyfish, and lots of smooth bay shrimp! Of course when we find salmon they are the real trophy prizes.

In this picture above are some of the CSC crew members (highschool kids working their summer jobs at The Natural Resource Crew of Community Service Consortium located in Newport, Oregon), and Jose who is at the very right of the photo. In this picture they are dragging back a tow to shore, we do about 6 tows per sampling day.

This picture above shows Jose preparing the sledge or commonly known as a “sled”. The sled works by having two very fine mesh nets that catches all of the smaller invertebrates that salmon eat. We carry out the sled into the surf, and lower it to wear it’s just surface deep, and drag it around a total of 400 meters, and all of the prey get scooped up into the net and end up in the codends at the end of the net. A couple of times we’ve accidently caught an English sculpin in the net, and an anchovy. We released the sculpin and kept the anchovy to bomb since they are also prey for the salmon.

This is a picture of a juvenile Chinook salmon that we caught while we were seining out in Alsea Bay. So far we have around 90 salmon that we’ve caught in the last 8 weeks.

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