**7. Summary**

398 Modern Telemetry

Fig. 45. Tag attached to pectoral fin. Fig. 46. Collection of data from tag in tank.

Fig. 47. Tag attached to dorsal scutes. Fig. 48. Tag attached to right pectoral fin and connected to sensor situated on the left pectoral

The feeding sensor pressure tag gave identical results to the data collected from the prototype experimental data. The major problem was attachment of the tag as the longest time for attachment was 12 days. The best location was on the surface of the pectoral fin and surprisingly there was little influence on normal use of the fin by lake sturgeon in a tank. Attaching the tag to the scutes was the least effective as the sharp boney scutes severed both wire and heavy fishing line with ease. Once the tag was not firmly attached the cannula was dislocated and either became clogged with mucous or was outside the branchial chamber and was unable to measure any pressure changes. There was no evidence of infection when the cannula was inserted through the tegument and the cartilage and once the cannula was removed there was no infection. The point at which the cannula was inserted was

Ventilation was characterized by alternating positive and negative pressure pulses whose amplitude and frequency were very constant when activity and temperature were stable.

fin.

undetectable within 2 weeks of its removal.

**6.4 Discussion** 

Lake sturgeon (*Acipenser fulvescens*) in Canada in the early 1900s were reduced to remnant populations over most of their historic range and extirpated from much of the Great Lakes and Lake Winnipeg. Populations continued to decline over the next 100 years due to commercial fishing pressure, hydroelectric and other industrial developments. This led in the early 2000s to the Committee on the Status of Endangered Wildlife in Canada recommending that lake sturgeon be listed as threatened or endangered in various regions of Canada. Most of the current research on lake sturgeon is related to environmental assessment for hydroelectric developments from perturbed areas where populations are low. The purpose of this research was to study a lake sturgeon population in an unperturbed system, the Pigeon River at Round Lake on the west side of Lake Winnipeg, Manitoba, Canada. Round Lake is a small isolated lake with a typical fish community found in the boreal region of Canada. The size of the sturgeon population relative to other fish species in the lake was determined by randomly set standard gang gillnets and all sturgeon caught were tagged with external and PIT tags and returned to the wild. Lake sturgeon comprised about 10% of the total population of fish. The main food item of lake sturgeon was mayflies and a detailed stomach analyses indicates that mayflies are important food for several other fish species. Since we were interested in determining how lake sturgeon, from

Movements and Habitat Use by Lake Sturgeon (*Acipenser fulvescens*)

of data and some of the analysis.

**9. References** 

18-26.

in an Unperturbed Environment: A Small Boreal Lake in the Canadian Shield 401

Province of Manitoba) for encouragement and logistical support. We thank Ph.D student Kate Gardiner for help with the illustrations. We also thank contractors Paul Coolie (substrate mapping) and Maria Begout (acoustic tag studies) for helping with the collection

Bajkov,A.D. and F. Neave. 1930. The sturgeon and sturgeon industry of Lake Winnipeg. *In*:

Baldwin, N.S., R.W. Saalfeld, M. A. Ross and H.J. Buettner. 1979. Commercial fish

Barth, C.C., S.J. Peake, P.J.Allen and W.G. Anderson. 2009. Habitat utilization of juvenile

Chiasson, W.B., D.L.G. Noakes and F.W.H. Beamish.1997. Habitat, benthic prey and

Choudhury, A., R. Bruch, and T.A. Dick. 1995. Helminths and food habits of lake sturgeon,

Choudhury, A. and T. A. Dick. 1998. Historical biogeography of sturgeons (Osteichthyes:

Choudhury, Anindo, Terry A. Dick, Harry L. Holloway, and Chris Ottinger. 1990. The lake

Dakota Water Resources Research Institute, Fargo, North Dakota, 121-133. Cummins, K.W. 1962. An evaluation of some techniques for the collection and analysis of

Dick, T. A. R. R. Campbell, N. E. Mandrak, B. Cudmore, J. Reist, J. Rice, P. Bentzen and P.

Dick, T. A., S.R. Jarvis, C.D. Swatzky and D.B. Stewart. 2006b. The lake sturgeon, An annotated bibliography. Can. Tech. Rep. Fish Aquat. Sci. iv + 252 p. Dick, T.A. 2004. Lake sturgeon studies in the Pigeon and Winnipeg rivers and biota indicators. Report prepared for Manitoba Hydro and Manitoba Model Forest. 445p Dick, Terry, Henry Letander, Kim Morriseau and Chris Paci. 1998. Namay an northern

Dick, T.A. and A. Choudhury. 1992. The lake sturgeon *Acipenser fulvescens* (Chondrostei:

Gr. Lakes Fish. Comm. TGech. Rep. 3. Available from

Bemis, W.E. and E.K. Findeis. 1994. The sturgeons' plight. Nature 370: 602.

www.gflc.org/databases/commercial/commerc.php

rivers. Can. J. Fish. Aquat. Sci. 54: 2866-2871.

Midland Naturalists 135: 274-282.

Journal of Biogeography 25: 623-640.

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Sciences No. 1861. 69p.

*fulvescens*. 154 p.

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Canadian Fisheries Manual. National Publications Ltd. Gardenville, Quebec. 43-47.

production in the Great Lakes 1867- 1977. pp. 6,30,31,70,84-85, 124-125, 158-159. IN:

lake sturgeon, *Acipenser fulvescens,* in a large Canadian river J. Appl. Ichthyol. 215:

distribution of juvenile lake sturgeon (*Acipenser fulvescens*) in northern Ontario

*Acipenser fulvescens* from the Lake Winnebago system, Wisconsin. The American

Acipenseridae): a synthesis of phylogenetics, palaeontology and palaeography.

sturgeon - *Acipenser fulvescens* (Chondrostei, Acipenseridae) in Canada: Preliminary studies on parasitofauna and immunological parameters. 1990 Interbasin Biota Transfer Study Program Proceedings (Eds., J.A. Leitch and D. J. Christensen), North

benthic samples with special emphasis on lotic waters. American Midland

Dumont. 2006a. Update COSEWIC status report on lake sturgeon, *Acipenser* 

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Acipenseridae): annotated bibliography. Can. Tech. Report Fisheries and Aquatic

juvenile to adults, utilized their environment a comprehensive study was undertaken. Round Lake was mapped using sonar technology to establish substrate types and current profiles were described at the inlet and outlet to the lake, and in the lake. The substrate map, based on roughness/smoothness and hardness/softness, were correlated with substrate types i.e. silt, fine sand, fine and coarse gravel, cobble, and rock.

Lake sturgeons were tagged using radio and acoustic tags. Radio tags were more useful to study movements in the river due to the high flows and air bubbles in the water but were limited because of the high labour input to track individual fish. Some of the acoustic tags had both temperature and pressure sensors and the application of the VRAP acoustic system (Vemco, Canada) enabled us to obtain 3-D positioning of individual fish in real time. Results from the lake sturgeon movement studies using acoustic tags showed that there was individual variation with some fish spending most of their time on the bottom while others spent up to 75% of their time in the water column. The amount of time spent in shallow and deep water and over substrate types was determined. The movements of large (over 5 kg) and small lake sturgeon (< 2 kg) often overlapped but there was a tendency to frequent different areas i.e. smaller lake sturgeon frequented the deeper parts of the lake but were also found in shallow sections near the main flow. The most frequently used sites by both groups of lake sturgeon were near the inlet and outlet from the lake where currents were up to 1m/sec. Larger lake sturgeon moved through regions of the river where currents were up to 2m/sec. Lake sturgeon were more active over substrates consisting of fine sand, cobble, and rock.

The conventional view is that lake sturgeons are primarily a bottom feeder. However, we noted that lake sturgeon fitted with pressure sensors moved up and down the water column and spent more time in the water column than previously thought based on a review of the literature. We noted that this movement was usually correlated with emerging mayflies and postulated we were likely observing a feeding event. This led to the development of a pressure tag with the potential to record feeding events in sturgeon by measuring branchial chamber pressure. The pressure sensor consists of a cannula (PE 160) attached to the positive port, inserted under the tegument and into the parabranchial cavity under the opercular flap such that most of the cannula was not exposed to the environment. The tip of the cannula did not interfere with the movement of the gill filaments. The resolution of the sensor was 1.85 pascals digital value-1 or 0.0189 cm freshwater at 4oC. The prototype sensor was designed to be attached by wires to the receiver to obtain physiological data. The second sensor was designed to transit the signal directly to a receiver. The reason for providing this example of sensor development (feeding in this case) is that with 3-D movement studies, using a VRAP system or the more recent VPS (Vemco Ltd.), researchers are not only able to record fine scale fish movements but with new sensors like the pressure sensor can pose new questions and drive technology, especially sensor technology, in new directions.

#### **8. Acknowledgments**

T. Dick acknowledges financial support for these studies from a Natural Sciences and Engineering Council of Canada operating grant and from the Department of Fisheries and Oceans Canada, Environment Canada, Manitoba Hydro and Manitoba Model Forest. T. Dick also thanks elder Henry Letander, Sagkeeng First Nations, Fort Alexander, Manitoba for advice on lake sturgeon and companionship in the field. We thank Dr. M. Papst (Department of Fisheries and Oceans Canada) and Keith Kristopherson (Fisheries Branch, Province of Manitoba) for encouragement and logistical support. We thank Ph.D student Kate Gardiner for help with the illustrations. We also thank contractors Paul Coolie (substrate mapping) and Maria Begout (acoustic tag studies) for helping with the collection of data and some of the analysis.
