Sunday, May 6, 2018

Week 5 - From Trawling to Final

The week started off with plenty of excitement! At 8am half of the BI450 class departed on the Elakha to start our trawling study of Yaquina Bay (the remaining half followed suit at 10:30am). The captain, Jeff Lawrence, walked us through safety procedures before we all adorned our very stylish neon orange life jackets. The rain pelted us for a large portion of the time we spent on deck so this was welcome insulation.

Before lowering the beam trawl a CTD was allowed to gently drift to a depth just above the bottom of the bay to record salinity and temperature for a solid minute. Once we got the trawl in the water we slowly continued our route for 7 minutes before bringing the trawl back up to see what we found.

Our first trawl yielded more crabs and shrimp than we ever wanted to see! We sifted through the invertebrates and debris in search of fish species, English sole in particular.
Once we recorded their length and performed a count we threw them back into
 the estuary. Our second trawl yielded even more grass shrimp and tons 
of flatfish (that’s more like it!).

The purpose of these trawls was to determine whether salinity affected the amount and size of English sole recruits within the bay. Once back at Hatfield we were afforded a break after our fish specimens had been placed in their tanks while the other students performed their trawls. Lecture was all about the early life stages and recruitment of larval fishes to a region. We then collectively compiled our trawling data and created relevant graphs and tables for our reports before heading to lab to identify our new tank residents.

Tuesday was our second time going to Tokatee Klootchman State Park, this time to hunt sculpins. We split up into pairs and were let loose on the tidepools to compete for who could collect the most sculpins, the largest sculpin, and the prettiest sculpin, etc. Sculpins are only one of the types of fish that will inhabit tidepools, but they are definitely more easily found than the others. Among all of us we temporarily kidnapped over 100 sculpins.

One container of sculpins caught. Most sculpins found were of the black/brown and white barred variety seen in the upper left corner of the bin.

Most of the sculpins we found seemed to be of the same species, based on their coloration. Large, almost chevron-shaped sections of brown or black alternating with white. We did find several small dark green sculpins, as well as another buffalo sculpin (Enophyrs bison '18). Two groups also found small larval snailfish, although we could not be sure of the species. One was found hiding in a large bed of kelp, and they look like pink tadpoles with white eyespots. After we awarded groups (and their nominated sculpin) candy prizes for who had the largest or prettiest sculpin (and the biggest haul), all but five or so sculpins were released back into the incoming tide.

As an exciting throwback mention to the Invertebrates section, we found quite a number of red rock crab (Cancer productus '18). Under one tidepool overhang, we saw a red rock crab fighting off a very gravid Dungeness crab (Cancer magister '18). In the same pool, there were at least three more red rock crabs sheltered in nooks and crannies.

Wednesday, Dr. Moritz Schmid guest lectured for us about plankton. The videos captured be the Situ Ichthyoplankton Imaging System (ISIIS) were really incredible to see! We spent the rest of the day editing our trawl reports and sketching specimens in our notebooks prior to making our way to the pump house dock. Light and minnow traps were deployed off of the dock in the bay to see what kind of zooplankton we could find the following morning. Once it gets dark the light in the light traps turn on and attract fish. The fish swim into the funnel shaped holes of the trap and remain there until collection the following day.

On Thursday morning, we recovered the two light traps and the two minnow traps that we had set out the evening before on the HMSC dock.

One of the minnow traps was empty, but the other had caught a handful of larval fish as well as a large buffalo sculpin (Enophrys bison '18). The light traps had more success, and caught a large number of larval fish as well as many unexpectedly cute larval crab. One trap also pulled up a large polychaete worm, who was returned to the water after several pictures were taken.

The class, putting out the traps on Wednesday evening.

We took the collected larvae back to lab to sort. We were focused on counting the number of larval fish caught as well as the number of larval crab, who were in the megalopae stage. After dividing the collection into 16ths, we again split into pairs to look through the sample, count the megalopae crab and the larval fish, and try to identify what other plankton we had found. Plankton is not a word restricted just to small krill and mystery microscopic organisms, what we commonly think of when the word plankton is said. Plankton refers to essentially any organism that is incapable of significant movement in the water - they must depend on drifting with water movement to move. In the plankton ID guide that we were given in lab, the guide included larval fish, small crustaceans, shrimp, small cnidarians, chaetognaths, and cephalopods. Aside from our targeted larval fish and megalopae, we found a small baby squid, some chaetognaths, larval barnacle molts, and many decapods and crustaceans.

The large, unidentified polychaete found in one of the light traps

Friday was pretty quiet here. Everyone was holed up in their apartments or the library getting some last minute studying in before our afternoon exam. We were fairly confident about the exam with the exception of the 30 fish families we needed to know but such is life. Afterward we all worked to help clean up the lab space for our next section on conservation policy with Sarah Henkel. Specimens were released into the bay and tanks were washed and scrubbed. The rest of the day was spent with everyone starting to unwind and enjoy their weekend.

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