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Fishing Derby set
CALUMET - The Calumet-Keweenaw Sportsmen's Club will host the Wal-Mart All-American Kids Fishing Derby at Swedetown Pond, Calumet from 9 a.m. to 3 p.m. Saturday.
Jungle Jog 5K
Event: Fifteenth M&T Bank Jungle Jog 5K road race, 8 a.m. Sunday at Seneca Park Zoo, Rochester. Course: 3.1-mile loop from trout pond, lower park area.
Phenotypic and Evolutionary Plasticity of Organ Masses in Response to Voluntary Exercise in House Mice1
SYNOPSIS. We used a novel mouse model to study the effects of selective breeding for high locomotor activity (14 generations) on relative organ sizes, hematocrit (Hct), and blood hemoglobin (Hb) concentration.
All three groups needed in outdoors
I drove across the state last weekend to attend the wedding of my friend's daughter, Maggie. Maggie, some devoted readers might recall, is a young woman, with a love of the outdoors and the subject of more than one article I've penned.
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Interior populations occur in British Columbia, the Yukon Territory, and Alaska in drainages of the Yukon River basin (Morrow, 1980; Haas and McPhail, 1991). Such populations were also assumed to occur in the mountainous drainages throughout the Mackenzie River valley (Hatfield et al., 1972; Dryden et al., 1973; Chang-Kue and Cameron, 1980), but the species identity for these locations is now suspect. Ecologically, Dolly Varden is primarily associated with rivers, especially in the Arctic, although some lacustrine populations are also known (McPhail, 1961; McCart, 1980; Morrow, 1980; Reist et al., 1997).
Bull trout is primarily recognized as a southern taxon found in interior drainages of western North America (Fig. 2). West of the continental divide, this species originally ranged south to 41[Symbol Not Transcribed] [degree]N (northern California) and north to northern British Columbia (Cavender, 1978; Haas and McPhail, 1991). In drainages east of the continental divide, bull trout occur from northern Nevada to northern Alberta and British Columbia (Lee et al., 1980; Haas and McPhail, 1991). Populations also occur in British Columbia in the headwaters of the Yukon River and the Liard River (drainage to the Mackenzie River), and a single northern population was identified in the southern Northwest Territories (NWT) ([Symbol Not Transcribed] [similar]61[Symbol Not Transcribed] [degree]N, 125[Symbol Not Transcribed] [degree]W, Prairie Creek) (Haas and McPhail, 1991). Ecologically, bull trout occur in relatively pristine cold waters (Lee et al., 1980), although high sensitivity to environmental disruption has restricted their present range (see below; Fitch, 1997; McCart, 1997; Watson and Hillman, 1997; Chan et al., 1999).
[Map Not Transcribed]
Co-occurrence of Dolly Varden and bull trout in the same drainages, as well as strict sympatry, has been noted in northwestern British Columbia (Fig. 2; Cavender, 1978; Haas and McPhail, 1991; Baxter et al., 1996). These findings and the previous scientific submergence of the bull trout taxon into Dolly Varden resulted in confusion in identifications (see Nelson and Paetz, 1992). These facts suggest that 1) work is required to clarify the geographic distribution of the two species, 2) care must be exercised when interpreting previous literature records identified as Dolly Varden, and 3) a summary of easily applied identification criteria would be helpful.
MATERIALS AND METHODS
The five "unknown" specimens reported here (41085, 42512, 42513, 43905, and 43906) were angled at the times and locations identified in Table 1. (Locations are also shown by stars in Figure 2.) All were frozen whole after capture, and shipped to the Freshwater Institute lab for processing. Where possible, data collected from individual fish included fork length, standard length, weight, gonad weight, sex, maturity, and otolith age (Table 1). Key qualitative identification data from the literature (Table 2) and quantitative identification data known to discriminate statistically between bull trout and Dolly Varden (Haas and McPhail, 1991; Table 3) were also collected.
The lack of clear Dolly Varden characteristics in these fish indicated an identification problem. Initial identities were hypothesized using qualitative key characters from the literature (Cavender, 1978; Page and Burr, 1991; Nelson and Paetz, 1992; Coad et al., 1995). These were confirmed using quantitative criteria provided by Haas and McPhail (1991) that have been shown to discriminate with 100% accuracy between the two most likely species. The identifications were also confirmed by comparison to known bull trout specimens reported in this study (., specimens from Alberta, Tables 1 and 3) as well as specimens from the University of Alberta museum collection.
RESULTS
These "unknown" specimens were captured in a region of the Mackenzie River originally thought to be within the geographical range of Dolly Varden (Fig. 1). However, the few studies conducted in this area have focused on the general biology of fish rather than on formal taxonomy (., Hatfield et al., 1972; Dryden et al., 1973; Chang-Kue and Cameron, 1980). An "unknown" char (41085, Table 1) was angled at the mouth of a small, unnamed creek flowing into the east side of the Mackenzie River immediately north of Birch Island on 8 August 1991. Such fish had been captured at this location in previous years by D. McDowell, and the specimen reported here was retained for further taxonomic examination. Preliminary identification of this specimen as a bull trout prompted further collections in the area on an opportunistic basis, which yielded the remaining four specimens reported here (42512, 42513, 43905, and 43906 in Table 1; Fig. 2). The Birch Island, Saline Creek, and Keele River capture locations are within about 30 km of each other. This area of the Mackenzie River is characterized by relatively high-gradient streams originating in mountainous areas to the immediate west and east of the river. The fourth capture location (Great Bear River) is approximately 80 km farther north (Fig. 2), and similar high-gradient rivers and creeks are present in the immediate vicinity.
The fish were small immature to large, sexually mature individuals that were unlikely to spawn that autumn (., resting), represented both sexes, and ranged in age from 8 to 14 years (Table 1). All fish were characterized by the following colouration (post-freezing). The background body colour was gray dorsally, whereas the ventral surface was cream, orange, or white anteriorly, grading to white posteriorly. Spots approximately the size of the pupil were present over much of the body and were slightly larger below the lateral line and on the caudal peduncle. Spots on the operculum and the dorsal portion of the body tended to be whitish, while spots on the sides of the body tended to be pinkish, white, or pale orange. Generally no spots were present on the fins: the exception to this was light spotting in some fish on the fleshy, scaled base of the caudal fin. The pectoral fins were unspotted, with orange-yellow as a ground colour and a white leading edge, typically followed by a strong, black line, or in some cases a smudge. The pelvic fins similarly were unspotted and yellowish in ground colour, with a white leading edge, and either no black colour or a light, blackish smudge of colour proximally in some individuals. The anal fin tended to be yellow-orange with white leading edges, occasionally followed by a black smudge in some individuals. The dorsal fin generally was uncoloured, unspotted, and semitransparent. This general description is consistent with the descriptions of bull trout in the literature (., Nelson and Paetz, 1992).
Fish Date Location
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Number
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41085 8 August 1991 Mackenzie River (Km 700)
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at Birch Island
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(64[Symbol Not Transcribed] [degree]12'N, 124[Symbol Not Transcribed] [degree]25'W)
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42512 17 July 1996 Mackenzie River (Km 828)
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42513 at Great Bear River
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(64[Symbol Not Transcribed] [degree]55'N, 125[Symbol Not Transcribed] [degree]39'W)
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43905 26 May 1998 Keele River, 15 km upstream of
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Mackenzie River (Km 736)
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(64[Symbol Not Transcribed] [degree]13'N, 125[Symbol Not Transcribed] [degree]47'W)
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43906 28 June 1998 Saline Creek
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(at Km 715 of Mackenzie River)
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(64[Symbol Not Transcribed] [degree]17'N, 124[Symbol Not Transcribed] [degree]31'W)
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43716 1993 Clearwater River, Alberta
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(52[Symbol Not Transcribed] [degree]31'N, 114[Symbol Not Transcribed] [degree]43'W)
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43717 1993 Wapiti River, Alberta
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(55[Symbol Not Transcribed] [degree]04'N, 118[Symbol Not Transcribed] [degree]48'W)
Fish Fork Weight Sex Maturity Gonad
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Number Length (mm) (g) Weight (g)
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41085 513 - female - -
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42512 642 3531 male resting
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42513 602 2976 male resting
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43905 333 351 unknown immature
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43906 473 1000 female immature
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43716 481 1175 female immature
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43717 680 3805 male resting
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Fish Age
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Number (years)
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41085 8+
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42512 14+
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42513 8+
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43905 8+
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43906 8+
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43716 10+
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43717 12+
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Several qualitative characteristics have been advanced as key characters for use in distinguishing between Dolly Varden and bull trout (Table 2) (Cavender, 1978; Nelson and Paetz, 1992; McPhail and Carveth, 1993; Coad et al., 1995; W. Roberts, University of Alberta, pers. comm. 1998). For all such criteria, the five "unknown" specimens in this study exhibited values consistent with bull trout rather than Dolly Varden. Thus, using dichotomous keys (., Nelson and Paetz, 1992; McPhail and Carveth, 1993), we identified all five fish as bull trout. The initial identification of the Birch Island specimen was also confirmed by comparison of its character values with those from known bull trout specimens at the University of Alberta Museum of Zoology. Furthermore, all "unknowns" were compared to two known bull trout from northern Alberta (43716 and 43717, Table 1) and exhibited similar qualitative characters (Table 2). Therefore, we conclude that the "unknown" specimens from the Northwest Territories are bull trout.
Haas and McPhail (1991) developed and tested the efficacy of a linear discriminant function for distinguishing between Dolly Varden and bull trout using three quantitative external characters: total branchiostegal ray count, principal anal ray count, and the ratio of upper jaw length to standard length. They demonstrated that this function was 100% accurate in discriminating the two species. This function correctly classified our known Alberta specimens (Table 3). Individual character values, as well as the discriminant score (which ranged from to ), confirmed the identification of all five "unknown" fish from the Northwest Territories as bull trout (Table 3).
DISCUSSION
The extension of the geographic range of bull trout north by approximately four degrees of latitude ([Symbol Not Transcribed] [similar]500 linear or 800 river km) is a considerable addition to the published range of this species. The repeated capture of these bull trout over a wide geographic area (and over time in at least one location) and the range of ages observed all indicate that these fish are not simply strays from known southern populations, but rather likely represent self-sustaining populations in this area. The size and remoteness of this area, its relatively pristine habitats, and the relatively light exploitation of fish resources are favourable to the presence of widespread, healthy populations of bull trout. However, both the full distribution and the actual status of the populations are unknown, and thus work is required to establish this information, especially in view of impending industrial development along the Mackenzie Valley.
Bull trout have been shown to be highly sensitive to a variety of individual and cumulative anthropogenic impacts (., McCart, 1997). Many populations in the southern areas of distribution are threatened, and some are extinct. Bull trout are slow-growing fish that mature late, spawn in nonconsecutive years, and likely have small population sizes (Haas and McPhail, 1991; McCart, 1997); all these characteristics heighten their sensitivity to impacts and complicate management. Thus, despite the remote locations of these northern populations, the extreme sensitivity to perturbation and the biological characteristics of this species raise conservation concerns. Impacts demonstrated as contributing to the decline of southern bull trout populations include restriction of migration by man-made structures; high susceptibility to overfishing; habitat disturbance from industrial activities, such as seismic, pipeline, forestry, and mining work; fragmentation of metapopulations through isolation of previously contiguous populations; and interaction with exotic species (McCart, 1997). Because the geographic extent of bull trout in the Northwest Territories is unknown, the real or potential negative impact of these factors cannot be assessed at this time. Furthermore, peripheral populations are more likely to be imperiled than those in central areas of the distribution; yet it is peripheral populations that may be genetically distinct, and thus most deserving of conservation (Lesica and Allendorf, 1995). Appropriate conservation and management measures need to be adopted in this area.
Character Dolly Varden Bull trout[1] NWT "Unknown" Fish[2]
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Position of eye relative to dorsal surface of head well below near top near top
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Distance from center of eye to dorsum, relative to distance from center of eye to nostril equal shorter shorter
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Upper jaw shape straight decurved decurved
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Upper jaw length just past eye well past well past
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Head shape laterally compressed laterally broad laterally broad
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Head size intermediate large large
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Gill raker size long, thin short, stout short, stout
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Gill raker shape compressed oval oval
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Presence of teeth on inner margin of gill raker none present present
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Dorsal fin height low high high
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Dorsal fin notch absent present present
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Transparency of dorsal fin no yes yes
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Presence of symphyseal knob absent present present
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Body form in cross-section compressed round round
[1] Literature description and characters of Alberta bull trout (43716, 43717: Table 1).
[2] Values for the five "unknown" fish (41085, 42512, 42513, 43905, 43906: Table 1).
The finding that bull trout likely exist as self-sustaining populations in the central portion (Sahtu Settlement Area) as well as southern areas of the Northwest Territories raises several issues that require comment. It calls into question the validity of many of the previous literature records for Dolly Varden in the Mackenzie River basin (squares in Fig. 1). Dolly Varden is recorded as occurring in the Athabasca, Slave, Liard, and Great Bear Rivers and in the upper main stem reaches of the Mackenzie River basin (Hatfield et al., 1972; Dryden et al., 1973; Chang-Kue and Cameron, 1980; McCart, 1986). Voucher specimens from these studies are not available, but given previous research (Haas and McPhail, 1991) and our findings, it is likely that these records represent bull trout. Thus, care must be exercised when interpreting literature records and accounts of Dolly Varden in this area, as is the case elsewhere in the ranges of these species (Haas and McPhail, 1991). This situation also points out the need for proper taxonomic research, as well as the need for deposition of voucher specimens, especially from studies conducted in remote and poorly studied areas.
Bull trout are likely more widely distributed in this area. They should occur in more upstream areas of the rivers and streams reported here and likely also in other similar systems draining into the Mackenzie River, both south and north of the locations we have documented. There is a need for widespread research and characterization of chars in this area to establish the true range of both bull trout and Dolly Varden. The nearest confirmed Dolly Varden within the Mackenzie River drainage are found along western, mountainous tributaries to the lower Mackenzie River (., Rat River, Vittrekwa River tributary to the Peel River, Big Fish River) and the Yukon North Slope rivers (., the Babbage and Firth Rivers) (Reist, 1989; Reist et al., 1997; . Reist, unpubl. data). Thus, assuming that the chars in the south and central portions of the Mackenzie River are largely bull trout, there is the possibility of an area of sympatry between the two species in the region between the Great Bear and Peel Rivers.
This range extension must also be considered in view of anticipated effects of climate change. This approach raises three possibilities (Reist, 1994): a) loss of critical thermal habitat could directly impact the bull trout in this area; b) bull trout from this area could extend their range north from wherever the northern boundary now is and come into sympatry with northern Dolly Varden (if the two species are not already sympatric); and c) other species could move north into this area and constitute a threat to these populations of bull trout. Any combination of these events will generally have negative consequences for these populations of bull trout. Bull trout are cold-water fish and require water temperatures of less than 13[Symbol Not Transcribed] [degree]C for much of their life history (., Baxter and McPhail, 1996 and references therein); thus, an increase in water temperatures as a result of climate change is likely to have a direct negative impact. Similarly, contact between bull trout and northern-form Dolly Varden raises the possibilities of hybridization and competition. Hybridization in natural strict sympatry in northern British Columbia does not widely occur, but natural hybrids between bull trout and Dolly Varden have been recorded (Haas and McPhail, 1991; Baxter et al., 1996). Since such an event would be more likely for taxa that have not naturally been in contact and have not developed relevant isolating mechanisms (McCart, 1997), this would be a future concern. Finally, as other fish species extend their distributions northwards under warming scenarios, competition or predation (or both) may affect these populations of bull trout.
Taxon/Fish Branchiostegal Ray Count Principal Anal Ray Count
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Dolly Varden 17-25 (22)[2] 9-13 (11)[2]
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Bull trout 22-31 (27)[2] 9-15 (12)[2]
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43716 27 10
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43717 29 10
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Unknowns
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41085 28 9
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42512 28 9
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42513 29 9
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43905 26 9
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43906 29 10
Taxon/Fish Upper Jaw Length (mm) Standard Length (mm)
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Dolly Varden - -
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Bull trout - -
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43716 431
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43717 610
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Unknowns
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41085 462
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42512 574
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42513 548
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43905 294
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43906 420
Taxon/Fish Discriminant Score[1]
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Dolly Varden
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Bull trout > 0
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43716
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43717
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Unknowns
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41085
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42512
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42513
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43905
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43906
[1] Linear discriminant function (LDF) from Haas and McPhail (1991): LDF Score = (total branchiostegal ray count) + (principal anal ray count) + (upper jaw length/standard length) - . Scores less than zero identify Dolly Varden; those greater than zero identify bull trout.
[2] Ranges including outliers and (medians) of characters from Haas and McPhail (1991).
The presence of a previously unknown species in this area raises fishery management concerns. Bull trout are sensitive to exploitation (McCart, 1997), but are not presently listed in the sport fishery regulations for the Northwest Territories (although this will change as of 1 April 2002; J. Tiemessen, Dept. of Resources, Wildlife and Economic Development, Government of the NWT, Yellowknife, pers. comm. 2002). Dolly Varden are listed, but no size or other restrictions are imposed (Northwest Territories and Nunavut Sport Fishing Guide, 2001). Similarly, bull trout are not recognized in the Sahtu Harvest Study, a legislated requirement to establish basic subsistence needs for the Dene of the area under the Sahtu Land Claim. All chars except lake trout are recorded as arctic char, which, as far as is known, do not occur in the area. Locally, such fish are referred to as red fish, silvers, or trout, or by their Slavey name, tuewa. The unknown distribution, status of populations, and local use in sport and food fisheries preclude proper fishery management. Bull trout need to be listed in appropriate management documents, formal guidelines must be created for fisheries targeting this species, and proper record keeping must be established. Similarly, managers of aquatic habitat in this area, at present the responsibility of Fisheries and Oceans Canada, must take into account the extreme vulnerability of this species to impacts that directly or indirectly affect aquatic habitat. Local activities include stream crossings by winter roads, exploration and related activities for mining, forestry activity, oil and gas extraction, potential pipeline construction along the Mackenzie River Valley, and dredging along the Mackenzie River. Upstream activities, the effects of which could be transported downstream to this area, include the above activities, as well as potential construction of large dams (., on the Liard River) and climate change (Bodaly et al., 1989; Reist, 1994).
In part as a result of this research, bull trout have been included in the recent assessment of status of species in the Northwest Territories and assigned the status of "may be at risk" (NWT Species 2000, 2001). Despite their remote location, bull trout in this area may experience a number of adverse impacts in the future. Clearly, appropriate research and management activities must be conducted to mitigate impacts and ensure conservation of these fish over the long term.
REFERENCES
BAXTER, ., and McPHAIL, . 1996. Bull trout spawning and rearing habitat requirements: Summary of the literature. Fisheries Technical Circular No. 98. Vancouver: Department of Zoology, University of British Columbia. 25 p.
BAXTER, ., TAYLOR, ., DEVLIN, ., HAZEN, J., and McPHAIL, . 1996. Evidence for natural hybridization between bull trout (Salvelinus confluentus) and Dolly Varden (S. malma) char in a north-central British Columbia watershed. Canadian Journal of Fisheries and Aquatic Sciences 54:421-429.
BEHNKE, . 1984. Organizing the diversity of the arctic charr complex. In: Johnson L., and Burns, ., eds. Biology of the arctic charr: Proceedings of the International Symposium on Arctic Charr. Winnipeg: University of Manitoba Press. 3-21.
BODALY, ., REIST, ., ROSENBERG, ., McCART, ., and HECKY, . 1989. Fish and fisheries of the Mackenzie and Churchill River basins, Northern Canada. In: Dodge, ., ed. Proceedings of the International Large River Symposium (LARS) held in 1986 at Honey Harbour, Ontario. Canadian Special Publication of Fisheries and Aquatic Sciences 106. Ottawa: Fisheries and Oceans. 128-144.
CAVENDER, . 1978. Taxonomy and distribution of the bull trout, Salvelinus confluentus (Suckley), from the American Northwest. California Fish and Game 64:139-174.
CHAN, J., FREDENBERG, W., LOHR, S., and SPALDING, S. 1999. Endangered and threatened wildlife and plants: Threatened status for bull trout in the coterminous United States: Final Rule. Federal Register 64(210):58910-58933. [Available at ./su_docs/aces/]
CHANG-KUE, .J., and CAMERON, . 1980. A survey of the fish resources of the Great Bear River, Northwest Territories, 1974. Fisheries and Marine Service Manuscript Report No. 1510. 59 p.
COAD, ., WASZCZUK, H., and LABIGNAN, I. 1995. Encyclopedia of Canadian fishes. Ottawa: Canadian Museum of Nature and Canadian Sportfishing Productions, Inc. 928 p.
DRYDEN, ., SUTHERLAND, ., and STEIN, . 1973. An evaluation of the fish resources of the Mackenzie River valley as related to pipeline development. Vol. 2. Environmental-Social Program, Northern Pipelines, Task Force on Northern Oil Development Report No. 73-2. 176 p.
FITCH, . 1997. Bull trout in southwestern Alberta: Notes on historical and current distribution. In: Mackay, ., Brewin, ., and Monita, M., eds. Friends of the Bull Trout Conference Proceedings. Calgary: Bull Trout Task Force (Alberta), c/o Trout Unlimited Canada. 147-160.
HAAS, ., and McPHAIL, . 1991. Systematics and distributions of Dolly Varden (Salvelinus malma) and bull trout (Salvelinus confluentus) in North America. Canadian Journal of Fisheries and Aquatic Sciences 48:2191-2211.
HATFIELD, ., STEIN, ., FALK, ., JESSOP, ., and SHEPHERD, . 1972. Fish resources of the Mackenzie River Valley. Interim Report 1, Vol. 2. Winnipeg, Manitoba: Department of the Environment, Fisheries and Marine Service. 289 p.
LEE, ., GILBERT, ., HOCUTT, ., JENKINS, ., McALLISTER, ., and STAUFFER ., Jr. 1980. Atlas of North American freshwater fishes. North Carolina State Museum of Natural History. 867 p.
LESICA, P., and ALLENDORF, . 1995. When are peripheral populations valuable for conservation? Conservation Biology 9:753-760.
McCART, . 1980. A review of the systematics and ecology of arctic char, Salvelinus alpinus, in the western Arctic. Canadian Technical Report of Fisheries and Aquatic Sciences 935. 89 p.
_____. 1986. Fish and fisheries of the Mackenzie system. In: Davies, ., and Walker, ., eds. The ecology of river systems. Dordrecht, Netherlands: W. Junk. 493-513.
_____. 1997. Bull trout in Alberta: A review. In: Mackay, ., Brewin, ., and Monita, M., eds. Friends of the Bull Trout Conference Proceedings. Calgary: Bull Trout Task Force (Alberta), c/o Trout Unlimited Canada. 191-208.
McPHAIL, . 1961. A systematic study of the Salvelinus alpinus complex in North America. Journal of the Fisheries Research Board of Canada 18:793-816.
McPHAIL, ., and CARVETH, R. 1993. Field key to the freshwater fishes of British Columbia. British Columbia Ministry of Environment, Fisheries Branch, Resource Inventory Committee. Victoria, British Columbia: Queen's Printer. 237 p.
MORROW, . 1980. The freshwater fishes of Alaska. Anchorage: Alaska Northwest Publishing Company. 284 p.
NELSON, ., and PAETZ, . 1992. The fishes of Alberta. 2nd ed. Edmonton: University of Alberta Press and Calgary: University of Calgary Press. 438 p.
NORTHWEST TERRITORIES AND NUNAVUT SPORT FISHING GUIDE. 2001. [Available at ../]
NWT SPECIES 2000. 2001. General status ranks of wild species in the Northwest Territories. [Available at .com/]
PAGE, ., and BURR, . 1991. A field guide to freshwater fishes of North America north of Mexico. Boston: Houghton Mifflin and Co. 432 p.
REIST, . 1989. Genetic structuring of allopatric populations and sympatric life history types of charr, Salvelinus alpinus/malma, in the western Arctic, Canada. Physiology and Ecology Japan, Special Volume 1:405-420.
_____. 1994. An overview of the possible effects of climate change on northern freshwater and anadromous fishes. In: Cohen, ., ed. Mackenzie Basin Impact Study (MBIS) Interim Report 2. Downsview, Ontario: Environment Canada. 377-385.
REIST, ., JOHNSON, ., and CARMICHAEL, . 1997. Variation and specific identity of char from northwestern Arctic Canada and Alaska. American Fisheries Society Symposium 19:250-261.
WATSON, G., and HILLMAN, . 1997. Factors affecting the distribution and abundance of bull trout: An investigation at hierarchical scales. North American Journal of Fisheries Management 17:237-252.
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