Massive Production

Last Tuesday our research crew (Brandon, Bailey, and I) made a trip down to MDC’s Lost Valley Hatchery. Our goal was to assist with the fall stocking effort of Lake Sturgeon in Missouri. When we walked through the open garage doors into the main production room we found ourselves on the floor of a veritable fish assembly line. Biologists worked at stations each completing a simple task with efficiency that would have made Henry Ford proud. The purpose of this assembly line wasn’t to build cars or electronics to stock in showrooms and on store shelves, but to tag baby Lake Sturgeon to stock in the Osage and Gasconade rivers.

Volunteers gathered around raceways to tag Lake Sturgeon at Lost Valley Hatchery

On the cuteness scale baby Lake Sturgeon rank somewhere between the Puppy Bowl and a tiny sloth taking a nap. Their long spade-shaped snouts turned ever so slightly upward at the tip. Their camo colored exterior specifically evolved to help them blend into the rocky bottoms of the streams they are born in to. Their five rows of sharp scutes discourage most hungry bass and catfish from trying to gobble them up. And there were 12 runways chock full of the things.

Like the migratory adults these fingerlings were already quite the travelers and you couldn’t blame them for being a little homesick. They started out as eggs obtained from adults in the Yellow River way up in Wisconsin. They were shipped down to Missouri where hatchery staff provided them with plenty of tender loving care to ease the transitions feeding them bloodworms, maintaining clean water and preventing disease.

The main job of the volunteer crews was to make sure Lake Sturgeon received two tags. At the first workstation biologists reached down into the water grab a sturgeon. Then using a scalpel they would scrape off the 9th spine or scute on the fish’s right side. The process was quick and relatively painless for the fish. Think of it like getting your nails trimmed. The marked fish was tossed into another tank to await transport to station #2.

Bailey removes a scute of a fingerling Lake Sturgeon to mark its stocking year.

At workstation #2, each Lake Sturgeon received a coded wire tag. When one worker had the needle in position another pushed a button on a machine to inject a 2 mm surgical steel tag into the fish’s back. This little piece of wire can be detected with a metal detecting wand, like the ones security folks use sometimes at airports. The positioning of this wire, more specifically what scute it is located under, will tell biologists what year it was stocked if they should encounter it in the future. This information can be used to estimate growth and survival in the population. The Sturgeon are tagged twice in case one of the marks is marks is obscured over time (sturgeon can lose other scutes or the coded wire tag may fall out).

Me inserting a coded wire tag into a sturgeon

At the end of the day, while a hungry crew gorged on grilled burgers and hotdogs, hatchery staff scooped up the Sturgeon in nets and hoisted them into the tank on a hatchery truck. A couple hours later they would be shot out of a hose and be swimming free.

The hatchery truck that will deliver lake Sturgeon to the river.

The outpouring of volunteers who showed up to see off the 5,000-6,000 fingerling Lake Sturgeon epitomizes how Lake Sturgeon recovery is a team effort. My work on movement and habitat selection by Lake Sturgeon being just one tiny component. Led and organized by our “foreman”, MDC Lake Sturgeon recovery biologist Travis Moore, we can continue to make progress in bringing this species back from the brink of extinction in the state. Even if it is just reporting and releasing Lake Sturgeon you catch, or practicing good land use practices that keep our water clean, like on the assembly line, each of us can have a small, but crucial, role to play.

Should I Stay or Should I Go

Human personality traits are often presented as dichotomies. You can get online, take a short test, and within minutes know if you are an extrovert or an introvert, a thinker or a feeler, a judger or a perceiver, and the list goes on. After about two months of tracking we are learning that Lake Sturgeon can be divided into two major categories: the movers and the stayers.

When you release a Sturgeon you never know how far it will go!

Some sturgeon just can’t seem to sit still for long. Adventurous sturgeon like Richard, Joe, Sigurd. Sigurd, named after one of my favorite nature writers and explorer of Canadian glacial lakes Sigurd Olson, was tagged back in 2015 by the Missouri Department of Conservation. Sigurd moved further upstream than any of our Sturgeon and came within a few miles of bumping his snout into Bagnell Dam in June. Over the past two months, Sigurd has moved at least 81.8 miles. And since it was tagged the total is at least twice that distance. Richard and Joe were Sturgeon we tagged this year. They quickly recovered from the tag implantation procedure and made significant upstream and downstream runs totaling at least 103 and 82 miles respectively. What is driving the restlessness in these fish remains unknown, but it may be related to characteristics of the individuals — our most mobile Sturgeon have been 20-30 lb males— and environmental conditions — sustained high flow releases from Bagnell Dam to combat upstream flooding gave way to lower summertime flows by mid June and as a result our big movers have transitioned back downstream to a few key pools.

Lake Sturgeon swimming away slowly into the depths of the Osage River.

We tagged plenty of homebodies too. Fish like Joe, Richard, and the ironically named Miles have found good homes and are content to stay there. These fish have remained within a 0.5 mile stretch of river since tracking began. We might worry that they were dead if it were not for subtle upstream movements between tracking periods.

The seasons also likely have an impact on Lake Sturgeon movement patterns. Most fish seem to be moving less as water temperatures rise to potentially stressful levels. Other papers have been published suggesting that water temperatures over 28 C are stressful for Lake Sturgeon. Our research may be able to highlight temperature or flow characteristics that Lake Sturgeon select for during these stressful periods. Perhaps by knowing a little bit about an individual Lake Sturgeon and the environmental conditions we will be able to predict its answer the proverbial  question that separates the movers from the stayers: Should I stay or should I go?

Bridges: We Drive Over them, Sturgeon Swim Under Them

I’ve finally emerged from a long blogging hiatus. This emergence coincides with an emergence from my troglodytic existence in the basement of ABNR Building on Mizzou’s campus. Troglodytic or cave dwelling, is not an exaggeration of how I have spent the winter. Unaccustomed to the brightness of the outside world, my first day in the field left me with a cherry-red face and moderate eye strain.

Soon the first warm days of the season will also rouse the Lake Sturgeon in Missouri’s rivers out of their winter sluggishness. As they begin to move they will likely be rather hungry as well. Hungry enough, we hope, to readily gobble a gob of nightcrawlers on our trotlines. After which we can surgically implant acoustic telemetry tags to track their movements over the next 4 years. But all of this work is for later posts. There are many preparatory activities that need to be made for the field season. 

 

Trotline hooks ready for use to catch some Lake Sturgeon!
Trotline hooks ready for use to catch some Lake Sturgeon!

 

The goals of the first forays into the field were to assess the potential study area which includes the larger tributaries to the Missouri River that we expect Lake Sturgeon to swim up during the spring in search of spawning habitat. My main focus is on the Osage and the Gasconade, but Lake Sturgeon are unpredictable, the Chariton, Grand, Lamine, and Moreau rivers might entice a wayward Sturgeon as well.  This leaves me and my trusty side-kick Brandon with 100’s of miles to patrol for the fish we tag, which unless we can find a house boat that can navigate these rivers, is an unrealistic goal.

However, there is another way around this. We can deploy “eyes” or rather “ears” to patrol these rivers for tagged Sturgeon 24-7. These ears are Vemco stationary receivers. These receivers have microphones built in that can detect the sound “pings” emitted by the tags implanted in our Lake Sturgeon. For example, we may tag a sturgeon in the Osage River. If this fish decides to swim up the Grand River within say 500 m of a stationary receiver, the receiver will log the fish’s tag number for us to download later.

Vemco VRTx Stationary Receiver. The very top point is where the microphone is located.
Vemco VRTx Stationary Receiver. The very top point is where the microphone is located.

The biggest issue with the stationary receivers is choosing the best place to set them to 1. prevent damage or loss during floods and 2. to prevent loss via theft (not sure why anyone would want one of these). One secure place researchers have used in the past are bridge piers, with permission from the Department of Transportation of Course. The river channel is the highway for migrating sturgeon and swimming upstream means they must pass under these bridges where we can observe their presence with stationary receivers during times we aren’t able to manually track them.

A good bridge pier for a stationary receiver is one that is in deep water, and has low flow velocity. Swift flow can create extra noise that interferes with the receiver’s microphone.

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Good bridge
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Bad Bridge

In addition to looking at bridges which isn’t terribly exciting, I also got a first look at some of my study sites. Some were more scenic than others. And some cool wildlife along the way.

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Scenic Gasconade River
Less scenic Chariton River. The Chariton is highly channelized and about 2 feet deep across the entire width of the river. The paddle I am holding is touching bottom.
Less scenic Chariton River. The Chariton is highly channelized because it is in an agricultural region of Missouri and about 2 feet deep across the entire width of the river. The paddle I am holding is touching bottom.
That is the muck that is on the bottom of the Chariton. Woe to the Sturgeon who swims up this river.
This is the muck that is on the bottom of the Chariton. Woe to the Sturgeon who swims up this river looking for spawning gravel.
Eagle nest in a sycamore along the Gasconade River.
Eagle nest with adult in a sycamore along the Gasconade River.