Daily Reflections

About 75% of the students in my Human Biology class at WSU are in their first year of college. A key skill beginning students like these need to develop is knowing how to study and learn in the college environment. The adjustment from high school can be very abrupt, and many of my beginning students are surprised that just showing up to class and copying down notes is no longer sufficient to achieve high success. As a result, I use assignments that create a high degree of course structure and incentivize good study and learning habits.

The primary assignment I use to help students develop strong study skills is a daily informal assessment of their learning progress and deficiencies. After every class meeting the students complete a “Daily Reflection” assignment where they briefly describe one interesting thing they learned, something that they still find confusing, and their upcoming study plans. My goal is to give students the opportunity to consider at least one concrete item they might spend extra time reviewing or discussing with classmates, and to show them a running list of their self-described learning and study habits.

These Daily Reflections are repetitious – by design! The assignment serves to remind students to spend small amounts of time studying course material on a regular basis, a much more effective way of learning information than long cram sessions immediately before exams. I get plenty of student push-back, which I address with a lesson on how learning and memory work, and why small, regular study sessions are more effective than cramming.

Octopuses at the Western Society of Naturalists

I just returned from Oxnard, CA, where I attended the meeting of the Western Society of Naturalists (WSN), and presented some preliminary findings on the octopus-rockfish interaction research I’ve been working on.

We’ve had GoPro cameras out at two occupied and two unoccupied octopus dens for the last month or so, recording one photograph every 10 minutes.

Here’s a time-lapse video of an unoccupied den, sped up to one real hour = one video second.  The thing to note is the lack of permanent fish.  You’ll see the occasional lingcod (Ophiodon elongatus) near the bottom, or Puget Sound rockfish (Sebastes emphaeus) flitting through, but no resident fish.

Next, here’s a video from an occupied den.  Note the copper rockfish (Sebastes caurinus) that just sit there near the den for hours at a time.  These are resident individuals that come here day after day.

Our analysis of these photos show that the two unoccupied dens had very infrequent copper rockfish visitations.  One of the two occupied dens had several resident copper rockfish.  However, the photos from the second occupied den did not show resident rockfish.  I think this is a function of the position of the camera, rather than a lack of fish.  The following video shows that this den has two major entrances, one from the side (that the GoPro sees) and one from above (that is not visible to the GoPro).  The video starts looking down from above, and then moves down to end with the view the GoPro has.  You can see two copper rockfish sitting in the den, with the large brown head of the octopus below them.

Every time we visit this den to change out the batteries, we always see two or three rockfish in the den, but these individuals are not visible from the position of the GoPro.  We’re working on solving this problem, and will be moving the cameras to a new position soon.

Here’s a copy of the poster I presented at WSN.  My coathors are: Derek Smith (Ph.D. student in Ken Sebens’ lab, working with me on this project), Michelle (Izzie) Brant (undergraduate student at FHL this quarter, helping analyze the photos), and Ken Sebens (my advisor).

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Limited change in the diversity and structure of subtidal communities over four decades

My former labmate, Dr. Robin Elahi, was the lead author on a paper that just came out in Marine Biology about community change on subtidal rock walls over the last 40 years.

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In the late 1960s to early 70s Charles Birkeland was a student at FHL, and photographed several permanent quadrats at Shady Cove, San Juan Island.  Our lab, led by Ken Sebens, has been monitoring similar walls at Shady Cove for the last seven years, allowing us to compare historic communities to present ones to look for introductions, extirpations, or changes in abundance.  Despite clear evidence of an increase in water temperature and predatory fish abundance, we observed only minimal differences – namely that historic communities appeared to be susceptible to more urchin and chiton grazing.  This result is promising in light of stories from other parts of the world where climate change and invasions are triggering major community shifts.

Elahi, R, C. Birkeland, K. Sebens, K. Turner and T. Dwyer.  In press.  Limited change in the diversity and structure of subtidal communities over four decades.  Marine Biology.  DOI 10.1007/s00227-013-2308-3.

Rockfish lavage

My research asks the question: do predatory fishes influence benthic communities?

To get there, we first had to determine exactly what those predatory fishes were eating.  The predators include lingcod, copper and quillback rockfish, and kelp greeling.  Anne Beaudreau, a former FHL graduate student, has already done a wonderful job of describing lingcod diets.  We chose to focus on rockfish diet.

Importantly, we wanted to sample rockfish diets without killing the fish.  Excision of the stomach is a common practice for examining stomach contents of fishes, but since rockfish populations are at risk in the Salish Sea, we didn’t want to contribute to their decline.  Gastric lavage, or stomach pumping, is a viable alternative, but had not been attempted with rockfish prior to our attempts.

Anesthesia bucket filled with 100mg/L buffered MS-222; Styrofoam cradle, with two channels for different fish sizes; Spring scale, meter stick and calipers; Hand-pumped garden sprayer.

Anesthesia bucket filled with 100mg/L buffered MS-222; Styrofoam cradle, with two channels for different fish sizes; Spring scale, meter stick and calipers; Hand-pumped garden sprayer.

We caught rockfish from less than 20m depth so as to reduce the risks of barotrauma.  This was both to reduce the risk of injury to the fish, and to ensure that the expanding gas bladder didn’t press on the stomach and cause the fish to vomit their stomach contents before we could catch them.  We also used barbless hooks to keep capture injuries to a minimum.

Once on board the boat, the fish were anesthetized in 100mg/L buffered tricaine methanosulfonate.  We had previously determined that this was a sufficient dosage to knock the fish out in about 5-10 minutes, keep them under for the 5-10 minutes of handling time, and then recover quickly in clean seawater.

Measuring the gape of a copper rockfish.

Measuring the gape of a copper rockfish.

After anesthetization, the fish were measured for mass, total length, body depth, and gape height and width.  We placed the fish upside down in a foam cradle and inserted a small plastic tube through the mouth and esophagus.  The hose end of a hand-pumped garden sprayer filled with clean seawater was inserted through the tube and into the stomach.  The sprayer hose size was stepped down in size and made smooth with surgical and Tygon tubing.

Inverted rockfish with tube and hose inserted into the esophagus.

Inverted rockfish with tube and hose inserted into the esophagus.

Because the garden sprayer was hand-pumped, we were able to easily adjust the amount of water pressure coming out of the hose.  We used this pressure to flush stomach contents out onto a collection screen.  Stomach contents were preserved in ethanol for later identification, and the fish were placed in a cooler of clean seawater to recover from anesthesia.

Several copper rockfish in the recovery cooler.

Several copper rockfish in the recovery cooler.

After the fish recovered from anesthesia we needed to return them to their capture depth, but their swim bladders were still inflated.  There are several methods for recompressing rockfish (see this video from NOAA SWFSC); we used an inverted weighted basket to return the fish.

Two copper rockfish in the return basket.

Two copper rockfish in the return basket.

Sending the rockfish back down.

Sending the rockfish back down.

We initially tested three individuals in the lab to establish an anesthetic dose and to learn the lavage methods.  All three individuals were kept for several days and appeared to recover without issues.  In our field work we captured and lavaged 29 fish, without any mortality or indication of significant injuries.  In the lab testing we offered shrimp to the rockfish, but failed to monitor how many shrimp were consumed, and we did not directly observe the fish feeding on the shrimp.  It is possible that the lavage procedure damaged or irritated the throat or stomach, preventing the fish from feeding.  If we were to repeat this work, we would want to monitor fish in the lab to determine when they start feeding again.

One of the projects that lavage could be used for is to monitor individual diets through time: fish could be tagged and recaptured and resampled periodically.  Copper rockfish are known to change their diets seasonally, with fish size, and at different locations.  Resampling individual rockfish would help determine if diet preferences are individual- or population-specific.  However, this would only be possible if the lavage procedure does not significantly alter feeding behavior.