Summer Fisheries Tech Wanted
for Chinook Salmon Research in Interior Alaska

Here's the flyer for this position, in case you arrived here without seeing it:

We created this webpage to provide additional details, so potential applicants can
determine if this job is for you and also highlight any relevant strengths.

Overview of the project

Here's the synopsis of this project from our funding proposal:

Chinook salmon (Oncorhynchus tshawytscha) are critical to subsistence in communities along major rivers of the Yukon River drainage in interior Alaska. Climate change is likely to challenge Chinook salmon in this area with increased water temperature and streamflow. Historically, Chinook population productivity has declined in years with sustained high flow during the period when juvenile Chinook are feeding in freshwater, probably due in part to reduced prey consumption and growth. Because the optimal temperature for growth of juvenile Chinook salmon is much lower when they are food-limited than when they are well-fed, determining the likely response to a warming climate requires understanding how conditions for prey consumption vary with streamflow. Therefore, this project will quantify spatiotemporal and flow-related variability in the concentrations of drifting prey and distracting debris in the Chena River basin, one of the major Chinook producers in interior Alaska and the watershed most heavily impacted by human development in the region. Locally-tested foraging and bioenergetics models will connect these measurements to field-validated juvenile growth predictions under current and projected future climatic conditions. These results will inform organizations restoring impacted habitat with finite resources about which areas have the requisite thermal and foraging conditions to support more juvenile Chinook salmon if other habitat qualities such as cover and connectivity are improved.

Curious candidates can can read much more about the research on our funding organization's website, especially in the Statement of Work.

Overview of the technician work

Our field technician will mostly lead a 2-person crew making day trips from ADF&G to use the drift sampling devices at three study sites per day. Usually these will be the same three sites on the Chena River, but some sampling will be done elsewhere in the watershed to study spatial variability. Occasional field days will instead involve navigating a jetboat on the river to trap and measure juvenile salmon, and placing or pulling temperature loggers.

The 2-person crew will consist, for the first few weeks, of the new technician and myself (South Fork Research ecologist Jason Neuswanger). After this training period, I'll go home to the Seattle area and remotely supervise our technician, who will lead the fieldwork with a rotating set of partners from the University of Alaska Fairbanks (UAF) and Alaska Department of Fish and Game (ADF&G). The changing set of partners means our technician will be responsible for knowing the entire procedure well enough to complete it smoothly with a second person who might be doing it for the first time.

Because this is the second season of the project, we've already worked a lot of the kinks out of the equipment, but it's guaranteed in any complex project with new technology that things will go wrong. We're looking for a technician with the ingenuity and persistence take the lead in solving problems such as a leaky camera box or a ripped gasket in a water pump (to give a couple examples from last year).

Schedule

The main fieldwork will run from approximately May 21st to August 31st, with a few trips extending into September for fish growth measurements and pulling loggers. Most work in September will be wrap-up in town. The exact schedule will be determined primarily by the weather, sometimes on fairly short notice. Because we're studying the response of drift to changes in flow, you'll likely have to spend at least a few days sampling in rainy weather when then river's rising. This weather dependence also means you'll also need to be available to sample on weekends if that's when conditions provide the kinds of flow patterns we want to sample. However, total days worked in the long run will be the same as a normal full-time job.

However, our preliminary guess based on last year is that there will be 46 total days in the field, split as follows:

This leaves approximately 35 workdays spent in town, either maintaining equipment at ADF&G or processing samples at UAF. Experience accurately identifying aquatic invertebrates to at least the family level is very desirable in a technician, but if we hire somebody without that experience, they will likely focus this lab time on sorting invertebrates from debris.

Equipment

Here's all the primary equipment you'd be using:

And a closeup of the pump system:

If you've ever deployed a standard drift net in a river before, which simply entails placing a net in the river and letting the current carry drifting bugs into it, you might wonder why we're using such a complicated contraption instead. The reason is that the juvenile Chinook Salmon we're studying eat lots of invertebrates (especially midge larvae) that are small enough to slip through the holes in the ~250-micron mesh of a typical drift net. However, if we use a fine enough mesh to catch these small invertebrates (like 85 micron), the net fabric itself creates so much resistance against the water that tricky eddy currents form within it and around its mouth, making it difficult to know how much water was filtered exactly, and even allowing bugs captured deep within the net to get washed back out the mouth. By pumping the water through nets dangling in the air, we can be certain nothing is washing out and know accurately how much water we filtered, all while using a very fine mesh to capture the smallest prey.

This is the first modern test of a system of its type to study the drift ordinary nets are missing, so it's exciting and novel research to be involved with as a tech. Results from the 2019 field season show that the new technology is paying off and showing much higher numbers of invertebrates than previous methods indicated. However, it's also pretty rigorous physical work in the field. The water is pumped by a 180-lb diaphragm pump, which has wheels on one side but is most convenient to carry with a person on each side. (Lighter-weight water pumps that use impeller-based designs would chop up the bugs; hence the heavy one.) The big aluminum frame that catches the flow and directs it through the nets weights about 100 lbs. The frame and hoses are held in place by heavy sandbags, because otherwise everything wobbles out of control. We can drive this gear to within about 30 feet of where it's deployed in most cases, but lifting it in and out of the truck and positioning it 3X/day is still a bit of a workout. If you like exercising in the name of science, this is a great job!

The other major piece of equipment you'd deploy at each site is a computer vision system, the black rectangle seen here in a longer timelapse from one of our overnight trips:

This system takes brightly-lit macro photos of a 2-cm-thick layer of water flowing beneath it at 2-second intervals for about an hour. Computer algorithms then detect and measure all the objects suspended in the drift. (You can learn more about that process in this 2015 blog post about an earlier prototype, if you're interested.) This allows us to get precise estimates of the size and number of suspended debris particles, which the fish mistake for prey. In fact, well over 90 % of the times when one of these fish appears to be chasing a bit of prey, it's actually pursuing and rejecting debris. This is important to mathematical models of their energy gained and lost, and to how those are affected by conditions in the river like streamflow.

Both of these systems run together for about an hour at each study site, during which you'll take a few other readings (turbidity, wind, light, etc.) and prepare to process the samples from the nets in the pump (the fine net you see from the outside, and a coarser one on the inside that protects it from damage). The processing looks something like this, although we've streamlined it a little bit since taking this video:

Salary and other compensation

There is no retirement package since this is seasonal employment. Technicians are responsible for their own lodging and transportation, both to/from Alaska and to/from the Fairbanks ADF&G office on workdays.

How to apply

Email Jason Neuswanger (jason@southforkresearch.org) with both a resumé and cover letter (<1 page) describing how you meet the qualifications, and two references with email and phone contact info.