Rudolfsen, T.*, Ruppert, J.W.R.*, Davis, C., Taylor, R., Watkinson, D. and M.S. Poesch (2019) Habitat use and hybridization between the Rocky Mountain Sculpin (Cottus sp.) and Slimy Sculpin (Cottus cognatus). Freshwater Biology 64(3): 391-404.

Citation: Rudolfsen, T.*, Ruppert, J.W.R.*, Davis, C., Taylor, R., Watkinson, D. and M.S. Poesch (2019) Habitat use and hybridization between the Rocky Mountain Sculpin (Cottus sp.) and Slimy Sculpin (Cottus cognatus). Freshwater Biology 64(3): 391-404.

Abstract

Anthropogenic factors such as land-use change, pollution and climate change, can cause fragmentation and reduce the amount of habitat by altering preferred conditions. This process can also bring about novel species interactions and, in some cases, create or alter levels of hybridization between closely related species. We assessed the threat of hybridization to persistence of the Rocky Mountain Sculpin (Cottus sp.) and the Slimy Sculpin (Cottus cognatus) in the Flathead River drainage, British Columbia, Canada. Using 731 genetic samples, 10 polymorphic microsatellite loci and mitochondrial cytochrome C oxidase sequences, we assessed: (1) if there are differences in the distribution of Rocky Mountain Sculpin between contemporary and historical (35 years ago) records, (2) if hybridization is symmetrical in terms of sex specific parental contributions, and (3) if habitat preferences contribute to the distribution of pure parental and hybrid populations. We identified three hybrid locations and found that Rocky Mountain Sculpin have a distribution (1200 – 1902 m) that far exceeds the range limit reported 35 years ago (1200 – 1372 m). Additionally, hybrid mating appears to involve similar proportions of parents of both sexes from each species. Lastly, elevation, water conductivity, turbidity, and dissolved oxygen are significant factors predicting the presence of parental species. Only elevation was significant to hybrid presence. The contrasting associations of parental species with different habitat types appears to influence the extent and distribution of hybridization.

*Lab members:   Tyana Rudolfsen,  Jonathan Ruppert, Mark Poesch. Check out opportunities in the lab!

Rudolfsen, T.*, Watkinson, D. and Poesch, M.S. (2018) Morphological divergence of the Threatened Rocky Mountain sculpin (Cottus sp.) is driven by biogeography and flow regime. Aquatic Conservation: Marine and Freshwater Ecosystems 28: 78-86.

Citation: Rudolfsen, T.*, Watkinson, D. and Poesch, M.S. (2018) Morphological divergence of the Threatened Rocky Mountain sculpin (Cottus sp.) is driven by biogeography and flow regime. Aquatic Conservation: Marine and Freshwater Ecosystems 28: 78-86.

Abstract

Stream hydrology is considered the primary factor in structuring freshwater fish communities,influencing stream habitats, food resources, and life‐history characteristics. Changes in stream hydrology, from climate change and anthropogenic sources (e.g. dams, irrigation channels), are thought to have adverse impacts on many freshwater species. The Rocky Mountain Sculpin (Cottus sp.) is a threatened species in Canada. Phenotypes of Rocky Mountain Sculpin were compared across a gradient of four streams differing in stream hydrology. It was hypothesized that Rocky Mountain Sculpin would show body forms minimizing drag in higher flow environments. Using geometric morphometrics and meristic counts, body shape, fin rays, and sensory pores were compared. As hypothesized, high‐flow river systems were correlated with sculpin with more dorso‐ventrally compressed, slender body shapes that minimized resistance to flow (P<0.001). Rocky Mountain Sculpin had more pectoral fin rays in populations with higher flows than lower flows,potentially allowing them to increase friction when gripping onto the substrate (P<0.001), and more anteriorly and dorsally located head pores to improve detection of floating prey (P<0.001). Biogeographic isolation and difference in flow regime were the likely basis for the observed morphological variation. The degree to which these phenotypes become fixed is unknown;however, since phenotypic diversity parallels genetic diversity in Rocky Mountain Sculpin,there is the possibility that persistent selection of these phenotypes can make it difficult to adapt to rapidly changing habitat conditions, such as changing flow. This study emphasizes the importance of considering phenotypic and morphological variation when evaluating how best to mitigate anthropogenic stressors and their impact on freshwater fishes.

* Lab members: Tyana RudolfsenMark Poesch. Check out opportunities in the lab!

Flow Regime across the range of Rocky Mountain Sculpin

Morphological Differences Across Populations (Dorsal view) of Rocky Mountain Sculpin

Ruppert, J.L.W.*, Docherty,C.*, Rudolfsen, T.*, Neufeld, K.*, Hamilton, K.*, MacPherson, L. and M.S. Poesch. (2017) Native North American freshwater species get out of the way: Prussian Carp (Carassius gibelio) establishment impacts both fish and macroinvertebrate communities. Royal Society Open Science 4: 170400.

Citation: Ruppert, J.L.W.*, Docherty,C.*, Rudolfsen, T.*, Neufeld, K.*, Hamilton, K.*, MacPherson, L. and M.S. Poesch. (2017) Native North American freshwater species get out of the way: Prussian Carp (Carassius gibelio) establishment impacts both fish and macroinvertebrate communities. Royal Society Open Science 4: 170400.

Abstract

Prussian carp (Carassius gibelio) are one of the most noxious non-native species in Eurasia. Recently, Prussian carp, a nonnative freshwater fish species, were genetically confirmed in Alberta, Canada and have been rapidly expanding their range in North America since establishment. Given their rapid range expansion, there is an increasing need to determine how Prussian carp may impact native species. We assessed the severity of the Prussian carp invasion by (i) determining their impact on fish communities, (ii) assessing their impact on benthic invertebrate communities, (iii) evaluating if Prussian carp alter abiotic conditions, and (iv) identifying where we find higher abundances of Prussian carp. When Prussian carp were established, we found significant changes to the fish community. Correspondingly, the degree of impact to benthic invertebrate communities was related to the stage of invasion (none, early or recent), where changes in fish communities were significantly concordant with changes in benthic invertebrate communities. Finally, we found that higher abundances of Prussian carp were significantly associated with lower abundances of a majority of native fish species. Altogether, using three lines of evidence, we determine that Prussian carp can have wide-ranging impacts on freshwater ecosystems in North America, pressing the need for management intervention.

*Lab members: Jonathan RuppertCassandra DochertyTyana RudolfsenKenton NeufeldKyle HamiltonMark Poesch. Check out opportunities in the lab!

Docherty, C.*, Ruppert, J.*, Rudolfsen, T.*, Hamann, A., and Poesch, M.S. (2017) Assessing the spread and potential impact of Prussian Carp (Carassius gibelio Bloch, 1782) to freshwater fishes in western North America. BioInvasions Records 6: 291-296.

Citation: Docherty, C.*, Ruppert, J.*, Rudolfsen, T.*, Hamann, A., and Poesch, M.S. 2017. Assessing the spread and potential impact of Prussian Carp (Carassius gibelio Bloch, 1782) to freshwater fishes in western North America. BioInvasions Records 6: 291-296.

Abstract

Prussian Carp (Carassius gibelio Bloch, 1782) is one of the most successful invasive species in Eurasia. Recently, Prussian Carp were genetically confirmed in Alberta, Canada, documenting the first detection of this species in North America. Given the close morphological similarity to their sister species, the Goldfish (Carassius auratus Linnaeus, 1758), it is likely that this species has been undetected for some time. We document the spread of Prussian Carp since arrival (circa 2000), and contribute a trait-based risk assessment to potential recipient communities in western North America. Using a meta-analysis of geo-referenced fisheries data in conjunction with original sampling in 2014, we show that the Prussian Carp range has increased by eight- to eleven-fold over 15 years in Alberta at a rate of approximately 233–1,250 km2 per year. Range expansions in the near future are possible through the Saskatchewan River drainage and south into the Missouri River basin, with easily accessible routes to Midwestern North America through irrigation canals. We show high life history trait overlap with other successful invasive species, such as Goldfish and Common Carp (Cyprinus carpio Linnaeus, 1758). Additionally, there was high life history trait overlap with several species of native sunfish (Centrarchidae) and suckers (Catostomidae). This study highlights Prussian Carp’s potential to widely impact North American freshwater ecosystems and to successfully compete with native taxa. Considered one of the worst invaders in Eurasia, the arrival of Prussian Carp in North America poses serious concern for fisheries managers. There is an urgent need to develop management plans before further range expansion and disruption of freshwater ecosystems by this new invasive species.

*Lab members: Cassandra DochertyJonathan RuppertTyana RudolfsenMark Poesch. Check out opportunities in the lab!

Spread of Prussian Carp in Alberta, Canada

Ruppert, J.L.W.*, James, P.M.A., Taylor, R., Rudolfsen, T.*, Veillard, M.*, Davis, C., Watkinson, D. and Poesch, M.S. (2017) Riverscape genetic structure of a threatened and dispersal limited freshwater species, the Rocky Mountain Sculpin (Cottus sp.). Conservation Genetics 18: 925-937.

Citation: Ruppert, J.L.W.*, James, P.M.A., Taylor, R., Rudolfsen, T.*, Veillard, M.*, Davis, C., Watkinson, D. and Poesch, M.S. 2017. Riverscape genetic structure of a threatened and dispersal limited freshwater species, the Rocky Mountain Sculpin (Cottus sp.). Conservation Genetics 18: 925-937.

Abstract

Understanding the movement ability and the spatial scale(s) of population genetic structure of species can together better ‘tune’ management objectives to prevent potential range contraction and population declines. We studied the Rocky Mountain Sculpin (Cottus sp.), a threatened species in Canada, to demonstrate the utility of using two complementary approaches to assess connectivity of a species. To do so, we used Passive Integrated Transponder (PIT) tags with a stationary tracking array (n = 223) to track movement and genetic data (n = 1,015) from nine microsatellite loci to assess genetic population structure. The PIT tag results indicated that Rocky Mountain Sculpin are sedentary; approximately 50% of individuals only moved a maximum distance of 10 meters (upstream or downstream) over a 5-month period. Genetic analyses indicated that at the spatial scale of our study area (5500 km2), watershed structure (river basins) is the main geographic feature influencing population genetic structure. We used the Bayesian clustering tool STRUCTURE, which suggested four distinct sub-populations of Rocky Mountain Sculpin in Canada. Genetic structure at finer spatial scales (within basins and sub-basins) appears to be influenced by fluvial distance (i.e., geographic distance along a river) and elevation change between sample locations (i.e., isolation-by-distance and isolation-by-environment). Combining movement and genetic analyses provides complimentary evidence of limited dispersal in Rocky Mountain Sculpin and highlights that both approaches together can provide broader insight into connectivity between populations that may ultimately help to aid future management decisions.

*Lab members: Jonathan RuppertTyana RudolfsenMarie VeillardMark Poesch. Check out opportunities in the lab!

STRUCTURE results showing mean assignment of individuals into four clusters and sorted by geographic locatoins. Geographic locations are abbreviated as FH: Flathead River, LC: Lee Creek, STM: St Mary River and NM: North Milk River.