A really big fish story

trevor.kenney — Fri, 12 Aug 2011 21:04:30 +0000

Some people go for leisurely fishing or boating excursions on the South Saskatchewan river, but ��Ѹ��Դ��߿�Ƭ of Lethbridge Master of Science candidate Christine Lacho recently spent a week on the water angling, tagging, and collecting data on Canada's largest freshwater fish, the Lake Sturgeon (Acipenser fulvescens).

Her work with the massive fish species will ultimately help inform the population's recovery strategy and listing decision under the Species at Risk Act.

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Lacho, (photo, right) works with Dr. Joe Rasmussen (Biological Sciences) and is in her first year of her Masters program. She was joined by Eztiaan Groenewald (Alberta Sustainable Resource Development) and World Wildlife Fund Canada (WWF-Canada)'s Mathieu Lebel, (photo, left) that organization's water management advisor.

Lebel submitted an extensive blog post to the WWF website, which is featured below. (Photos courtesy Mathieu Lebel/WWF Canada).

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Have you ever had one of those weeks at work you hoped would never end? I recently did. But of course it's not every week I get to join researchers on a week-long expedition angling, tagging, and collecting data on Canada's largest freshwater fish, the Lake Sturgeon (Acipenser fulvescens).

In a recent blog post, (http://www.wwf.ca) Emily Giles and I briefly described why Lake Sturgeon fascinate us. So you can imagine my excitement to have the opportunity to assist a collaborative research effort lead by Alberta Sustainable Resource Development and Fisheries and Oceans Canada and in collaboration with the ��Ѹ��Դ��߿�Ƭ of Lethbridge on Lake Sturgeon in the Alberta portion of the South Saskatchewan River system, that will ultimately help inform the population's recovery strategy and listing decision under the Species at Risk Act.

The research project is intensive and involves deploying and retrieving multiple (~40) data receivers throughout the river system, angling and tagging Lake Sturgeon at a number of locations, and tracking the movement of the fish with the receivers as well as by boat.

I was fortunate to get to do a little bit of almost everything during the week I spent in the field with lead researcher Christine Lacho (��Ѹ��Դ��߿�Ƭ of Lethbridge) and Eztiaan Groenewald (Alberta Sustainable Resource Development).

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Christine and Eztiaan Groenewald download information from a data receiver

Not surprisingly, a very enjoyable part of the field work was the time I spent angling for Lake Sturgeon, which often make spectacular jumps out of the water and long runs. We caught several adults and juveniles, and I must admit the thrill of catching a Lake Sturgeon only grew as the week went by and unfortunately, had to end.

To better understand population dynamics and growth, all Lake Sturgeon that were caught were quickly measured, weighed, marked with floy and PIT (passive integrated transponder) tags, and clipped in a small area of a pectoral fin for ageing, before being released back into the river.

The main focus of this research though is to learn more about the fish's distribution, movement, seasonal habitat use, and potential critical habitat locations. To accomplish this, acoustic tags were surgically inserted into adults and a small number of juveniles.

The acoustic tags transmit a signal to data receivers, which allows researchers and government agencies to identify the locations of key Lake Sturgeon habitat, when and for how long it is being used, and the extent and timing of movement between habitats.

Another key component of the field work was to retrieve data receivers from the river bottom by locating them using a GPS (Global Positioning System) unit and 'fishing' them out using grappling hooks.

Although this may sound fairly straightforward, negotiating fast-moving and sediment-laden water can be challenging and it is also possible that river processes may have shifted a receiver's location from where it was deployed.

Once we were able to hook onto a receiver, the next part involves hauling it, and the 80-pound concrete block it is fastened to, into the boat which is, as you can guess, a great workout.

This process makes the retrieval very rewarding, most importantly because critical research data can be downloaded from the receiver and used to better understand and ultimately protect Lake Sturgeon.

Now, back at my desk, I am left with great admiration for the dedication of the researchers involved in and resources being put towards this project, and of course a much deeper appreciation for the fascinating Lake Sturgeon.

It was an incredible experience to work with these ancient fish and researchers and something I will always remember. Field work is still underway so it will be some time before results are available.

In the meantime, stay tuned on further efforts to recover and conserve Lake Sturgeon and the river habitats that are vital to their survival.

Learn more about WWF Canada at this website: http://wwf.ca/

UNews - Mathieu Lebel

A really big fish story

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