**1. Introduction**

370 Modern Telemetry

Taillade, M. "Chap. 21. Animal tracking by satellite." In Wildlife Telemetry, Remote

Timko, RE, and AL. Kolz. "Satellite Sea Turtle Tracking," Marine Fishery Review 44(4)

Wyneken, J, SV. Madrak, M. Salmon, and J. Foote. "Migratory Activity by Hatchling

New York: Ellis Horwood Ltd., 1992.

Groups," Marine Biology 156 (2008): 171-181.

(1982): 19-24.

Monitoring and Tracking of Animals, edited by Priede, IG, and SM. Swift, 149-160.

Loggerhead Sea Turtle (*Caretta caretta*): Evidence for Divergence Between Nesting

The order Acipenseriformes, belonging to a group of basal Acthopterygian fishes (Choudhury and Dick 1998**),** has two living families (Acipenseridae and Polyodontidae), 6 genera**,** and 26 species worldwide (Nelson and Paetz, 1992; Nelson 1994**).** The Acipenseridae are old with the fossil record of sturgeon like fish dating back 100 million years to the upper Cretaceous (Harkness and Dymond 1961, Fogle 1975, Pearce 1986, Mecozzi 1988, Choudhury and Dick 1998**).** Fossils of an extinct family, the chondrosteidae, are dated from the lower Jurassic to the lower Cretaceous **(**Scott and Crossman 1998**).** Other authors state that sturgeon species are primitive relicts of the Devonian period 300 million years ago (Glover 1961, Ono et al. 1983, Houston 1987). Choudhury and Dick (1998) suggest that acipenserid**s** diversified within a narrow time frame and lapsed into a subsequent long period of morphologica1 stasis**.** 

The lake sturgeon has the most local names of al1 North American sturgeon species. These names include: rock, common, red, ruddy, Ohio, stone, shell-back, bony, freshwater, smooth-back, rubbernose**,** black, dogface, bull-nosed and Great Lakes sturgeon (Harkness and Dymond 1961, Williams and Vondett 1962, Scott and Crossman 1998), Pearce 1986, Mecozzi 1988).

The decline of sturgeon populations throughout the world (Bemis and Findeis, 1994) and in North America is well documented. Population numbers plummeted around the turn of the 20th century as a result of over-fishing (Prince, 1905, Dick et al. 1998). The continued decline of populations across Canada is due to a variety of factors including habitat loss, continued fishing pressure in the form of commercial, sport, and subsistence fisheries. Consequently, the Committee on the Status on Wildlife in Canada (COSEWIC) raised major concerns on the status of the species and a report was written for Canada by Dick et al. (2006a). Considerable effort has gone into sturgeon research over the past two decades and since then the understanding of lake sturgeon biology and habitat use has improved, facilitating the possible rehabilitation of some populations. The Manitoba records on lake sturgeon population declines are relatively complete because there are good historical records for lake

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

Fig. 1. Map of the Pigeon River, from Family Lake to Lake Winnipeg.

Fig. 2. The composition of fish Fig. 3. The abundance of prey items in the species in Round Lake. stomach contents of each individual species of

Percent Total Abundance

Ephemeridae

Gomphidae

Perch Walleye Sauger Mooneye Pike suckers

Siphlonuridae

Hydropsychidae

Chironomidae

Gammaridae

Prey Category

Pelycapoda

Gastropoda

Corixidae

Notonectidae

fish

fish in Round Lake.

Percent Total Catch

Other

WhtSucker

Pike

Redhorse

Sauger

Round Lake Fish Species

Walleye

Mooneye

Perch

Sturgeon

in an Unperturbed Environment: A Small Boreal Lake in the Canadian Shield 373

sturgeon harvests from commercial fisheries (Prince, 1905; Bajkov and Neave, 1930; Baldwin et al. 1979, Choudhury et al. 1990), and the aboriginal communities have a strong knowledge base and a long fishing and cultural connection to sturgeon **(**Holzkamm and Wilson, 1988; Dick et al. 2002).

Information on lake sturgeon (*Acipenser fulvescens*) in North America was first compiled by Dick and Choudhury (1992). A considerable amount of new data has been accumulated since the early 1990s on lake sturgeon in North America and in Canada **(**Dick et al. 2006b). This document clearly shows that the national trends for lake sturgeon populations are a general decrease in numbers with some of the decline attributed to environmental perturbation. However, not all declines are due to environmental perturbations, for example, the recent decision by the Province of Quebec to reduce the commercial fishery quota on what was considered viable stocks indicates that commercial fishing still has a major impact on a few sturgeon populations **(**Dick et al. 2006a**)**. Furthermore, continued fishing of any sort on numerous sturgeon stocks across Canada will have a detrimental affect on their chances of survival. According to current information there are atleast six distinct genetic stocks across Canada, therefore rehabilitation programs will be limited by restrictions on the transfer of stocks across major watersheds (Ferguson and Duckworth, 1997; Ferguson et al. 1993).

Today, a substantial amount of information is available on the general state of most lake sturgeon populations across Canada and the United States, the natural fragmentation of sturgeon populations, and how to retrospectively view lake sturgeon distributions. We also have some idea of what constitutes "good" sturgeon habitat, the habitat by juvenile sturgeon in natural systems (Chiasson et al. 1997; Barth et al. 2009), and new information on genetic diversity and rare phenotypes of lake sturgeon in a Canadian contex (Ferguson and Duckworth 1997; Ferguson et al. 1993).

The objectives of this study were to develop methods to study movements and habitat use by lake sturgeon, especially subadults and juveniles and develop tags that provide data on specific activities such as feeding. This study was designed to collect data on lake sturgeon movements and then to attempt to define habitat by describing substrate and currents in the vicinity of their movements. The Pigeon River was chosen because there was a relatively confined population in Round Lake, which would allow for fine scale movements to be assessed without the complications of immigration and emigration. Most of the data on which this chapter is based is from research conducted in Round Lake, Manitoba, Canada and from the laboratory of T. Dick at the University of Manitoba. No attempt was made in this chapter to provide a complete literature review of lake sturgeon as this has been published elsewhere (Dick et al. 2006b).

*Round Lake study area***:** Round Lake is located on the Pigeon River which flows from Family Lake to Lake Winnipeg (Fig. 1). It is a small isolated lake in eastern Manitoba, Canada that was never commercially fished and consequently has remained a relatively unperturbed and an important reference lake for lake sturgeon studies. The study area included the Pigeon River in the vicinity of Round Lake, areas upstream from the lake to the first set of falls, Grant Falls, and downstream of the lake to the first set of falls. Round Lake has a typical boreal lake fish species compositions plus lake sturgeon. The fish species composition in Round Lake is illustrated in Fig. 2**.** Diets of fish species collected from Round Lake are presented in (Fig. 3) and lake sturgeon consumed mostly mayflies, clams and amphipods (based on the gavage method, see Dick (2004). Lake sturgeons are about 10% of the fish community based on catch per unit effort.

sturgeon harvests from commercial fisheries (Prince, 1905; Bajkov and Neave, 1930; Baldwin et al. 1979, Choudhury et al. 1990), and the aboriginal communities have a strong knowledge base and a long fishing and cultural connection to sturgeon **(**Holzkamm and Wilson, 1988;

Information on lake sturgeon (*Acipenser fulvescens*) in North America was first compiled by Dick and Choudhury (1992). A considerable amount of new data has been accumulated since the early 1990s on lake sturgeon in North America and in Canada **(**Dick et al. 2006b). This document clearly shows that the national trends for lake sturgeon populations are a general decrease in numbers with some of the decline attributed to environmental perturbation. However, not all declines are due to environmental perturbations, for example, the recent decision by the Province of Quebec to reduce the commercial fishery quota on what was considered viable stocks indicates that commercial fishing still has a major impact on a few sturgeon populations **(**Dick et al. 2006a**)**. Furthermore, continued fishing of any sort on numerous sturgeon stocks across Canada will have a detrimental affect on their chances of survival. According to current information there are atleast six distinct genetic stocks across Canada, therefore rehabilitation programs will be limited by restrictions on the transfer of stocks across major watersheds (Ferguson and Duckworth,

Today, a substantial amount of information is available on the general state of most lake sturgeon populations across Canada and the United States, the natural fragmentation of sturgeon populations, and how to retrospectively view lake sturgeon distributions. We also have some idea of what constitutes "good" sturgeon habitat, the habitat by juvenile sturgeon in natural systems (Chiasson et al. 1997; Barth et al. 2009), and new information on genetic diversity and rare phenotypes of lake sturgeon in a Canadian contex (Ferguson and

The objectives of this study were to develop methods to study movements and habitat use by lake sturgeon, especially subadults and juveniles and develop tags that provide data on specific activities such as feeding. This study was designed to collect data on lake sturgeon movements and then to attempt to define habitat by describing substrate and currents in the vicinity of their movements. The Pigeon River was chosen because there was a relatively confined population in Round Lake, which would allow for fine scale movements to be assessed without the complications of immigration and emigration. Most of the data on which this chapter is based is from research conducted in Round Lake, Manitoba, Canada and from the laboratory of T. Dick at the University of Manitoba. No attempt was made in this chapter to provide a complete literature review of lake sturgeon as this has been published

*Round Lake study area***:** Round Lake is located on the Pigeon River which flows from Family Lake to Lake Winnipeg (Fig. 1). It is a small isolated lake in eastern Manitoba, Canada that was never commercially fished and consequently has remained a relatively unperturbed and an important reference lake for lake sturgeon studies. The study area included the Pigeon River in the vicinity of Round Lake, areas upstream from the lake to the first set of falls, Grant Falls, and downstream of the lake to the first set of falls. Round Lake has a typical boreal lake fish species compositions plus lake sturgeon. The fish species composition in Round Lake is illustrated in Fig. 2**.** Diets of fish species collected from Round Lake are presented in (Fig. 3) and lake sturgeon consumed mostly mayflies, clams and amphipods (based on the gavage method, see Dick (2004). Lake sturgeons are about 10% of the fish

Dick et al. 2002).

1997; Ferguson et al. 1993).

Duckworth 1997; Ferguson et al. 1993).

elsewhere (Dick et al. 2006b).

community based on catch per unit effort.

Fig. 1. Map of the Pigeon River, from Family Lake to Lake Winnipeg.

Fig. 2. The composition of fish Fig. 3. The abundance of prey items in the species in Round Lake. stomach contents of each individual species of fish in Round Lake.

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

(VRAP) system. Round Lake.

transmitter, an omnidirectional hydrophone, and a VHF modem.

the lake. Figure 5 shows the distribution of the two 3-receiver arrays.

4017. For each location on each day bottom depth was determined.

was imported from the VEMCO system program.

**2.2 Telemetry data** 

available.

attachment are outlined above.

in an Unperturbed Environment: A Small Boreal Lake in the Canadian Shield 375

BASE STATION

Fig 4. Diagram of the Vemco Fig. 5. Location of the two acoustic arrays in

Precise positioning of lake sturgeon was done using two radio linked acoustic positioning arrays (VRAP, Vemco Ltd.). Each array consisted of a base station which communicated with each of three buoys anchored in the lake (Fig. 4). Each buoy contained an acoustic

Buoy location was determined using survey techniques and having an understanding of the lake morphometry so that there was a clean line of site between receivers so that a tag signal was picked up by atleast two receivers. Test tags determined if a signal could not be picked up by a receiver due to an under water obstruction, such as a boulder, and if the receiver was obstructed it was re-positioned. The chosen positions covered 80% of the surface area of

Telemetry data analysis and presentation was done using Idrisi for Windows (Clark University, MA). Some maps were created in Idrisi for Windows. Acoustic telemetry data

Determination of depth selection and substrate selection was done by hand. Seven days were selected for analysis. Selection was based on movements to include the widest possible range of movement patterns. Days 206 and 221 were selected for sturgeon 4014. Days 210 and 222 were selected for sturgeon 4015. Days 206, 211 and 219 were selected for sturgeon

Swimming depth minus bottom depth was calculated to determine all locations in which the fish was in contact with the substrate. All values of 1 or less were included. All figures and comments pertaining to substrate selection only include locations in which a fish was in contact with the bottom. Other location statements and figures used all the positional data

*Radio tags*: These tags were attached externally to the dorsal fin. Initially, a piece of foam was placed between the tag and the dorsal fin and a piece of foam and a plastic backing were placed on the opposite side of the fin for support of the attachment wires. Details on tag
