Category Archives: Species at Risk

There has been a dramatic decline in freshwater fish biodiversity globally, and this is true in Canada as well. Losses of freshwater fishes have important consequences to Canadians. Freshwater fish provide forage for other biota, drive ecosystem properties, and are indicators of aquatic ecosystem health. In the PoeschLab, we study the declines of freshwater fishes, including species like: Arctic Grayling, Athabasca Rainbow Trout (Endangered), Bull Trout (Special Concern), Carmine Shiner (Threatened), Lake Sturgeon (Saskatchewan River, COSEWIC: Endangered), Plains Sucker (Milk River Population – Threatened), Redside Dace (Endangered), Rocky Mountain Sculpin (Eastslope Population – Endangered), Western Silvery Minnow (Threatened), Westslope Cutthroat Trout (AB Population – Threatened), among many others.

Pandit, S.N., Koriala, L., Maitland, B.M, Poesch, M.S., and E. Enders. (2017) Climate change risks, extinction debt, and conservation implications for an endangered freshwater fish Carmine Shiner (Notropis percobromus). Science of the Total Environment 598: 1-11.

Abstract:

Climate change is affecting many freshwater species, particularly fishes. Predictions of future climate change suggest large and deleterious effects on species with narrow dispersal abilities due to limited hydrological connectivity. In turn, this creates the potential for population isolation in thermally unsuitable habitats, leading to physiological stress, species declines or possible extirpation. The current extent of many freshwater fish species’ spatio-temporal distribution patterns and their sensitivity to thermal impacts from climate change − critical information for conservation planning − are often unknown. Carmine shiner (Notropis percobromus) is an ecologically important species listed as threatened or imperilled nationally (Canada) and regionally (South Dakota, United States) due to its restricted range and sensitivity to water quality and temperature. This research aimed to determine the current distribution and spatio-temporal variability in projected suitable habitat for Carmine shiner using niche-based modeling approaches (MaxEnt, BIOCLIM, and DOMAIN models). Statistically downscaled, bias-corrected Global Circulation Models (GCMs) data was used to model the distribution of Carmine shiner in central North America for the period of 2041–2060 (2050s). Maximum mean July temperature and temperature variability were the main factors in determining Carmine shiner distribution. Patterns of projected habitat change by the 2050s suggest the spatial extent of the current distribution of Carmine shiner would shift north, with > 50% of the current distribution changing with future projections based on two Representative Concentrations Pathways for CO2 emissions. Whereas the southern extent of the distribution would become unsuitable for Carmine shiner, suitable habitats are predicted to become available further north, if accessible. Importantly, the majority of habitat gains for Carmine shiner would be in areas currently inaccessible due to dispersal limitations, suggesting current populations may face an extinction debt within the next half century. These results provide evidence that Carmine shiner may be highly vulnerable to a warming climate and suggest that management actions – such as assisted migration – may be needed to mitigate impacts from climate change and ensure the long-term persistence of the species.

Citation: Pandit, S.N.*, Koriala, L., Maitland, B.M*, Poesch, M.S., and E. Enders. (2017) Climate change risks, extinction debt, and conservation implications for an endangered freshwater fish Carmine Shiner (Notropis percobromus). Science of the Total Environment 598: 1-11.

Predicted Change in Carmine Shiner Distribution given Climate Change Scenarios (RCP 2.6 top; RCP8.5 bottom) across various thresholds

Also Read:

Poesch, M.S., Chavarie, L., Chu, C., Pandit, S.N.*, and W. Tonn. (2016) Climate change impacts on freshwater fishes: A Canadian perspective. Fisheries 41(7): 385-391.

*Lab members: Shubha Pandit, Bryan Maitland, Mark Poesch. Check out opportunities in the lab!

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.

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.

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.

Also Read:

Nelson-Chorney, H.*, Carli, C.M., Davis, C.S., Vinebrooke, R.D., Poesch, M.S., and M.K. Taylor (2019) Environmental DNA in lake sediment reveals biogeography of native genetic diversity. Frontiers in Ecology and Evolution 17: 313-318.

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

Maitland, B.M.*, Anderson, A. and Poesch, M.S. (2016) Prioritising culvert removals to restore habitat for at-risk salmonids in the Boreal forest. Fisheries Management and Ecology 23: 489-502.

Abstract:

Stream crossing structures are an increasingly prevalent anthropogenic feature on North American riverscapes, particularly in watersheds affected by industrial resource development in sensitive boreal environments. If improperly managed, stream crossings have the potential to alter fish habitat and impede fish movement. This study assessed instream habitat characteristics and fish communities from 33 culverted, bridged and reference streams in an industrialising region of the boreal forest in west-central Alberta. Mixed-effects modelling and multivariate analysis were used to determine impacts of stream crossings at three scales: whole-stream scale, within-stream scale and the interaction of scales. Instream habitat characteristics such as mean depth, water velocity, percent fines, turbidity, water temperature and dissolved oxygen showed significant between-stream as well as within-stream differences among stream crossings. The majority of fish species exhibited significantly lower densities (n m−2) in upstream habitats as compared to downstream habitats, including a significant reduction in Slimy Sculpin densities in culverted streams. Multivariate tests corroborated these results, showing that fish assemblages differ as a function of stream type. This study suggests industrial stream crossings influence abiotic habitat characteristics in freshwater ecosystems, restrict biotic connectivity and impact fish community structure at the whole-stream and within-stream scales. Alterations to stream ecosystems associated with stream crossings may be driving large-scale changes in stream fish communities in the boreal forest. With expanded development expected in much of North America’s boreal region, mitigation measures which limit impacts from stream crossings are needed to ensure proper ecosystem function in freshwater systems.

Citation: Maitland, B.M.*, Anderson, A. and Poesch, M.S. (2016) Prioritising culvert removals to restore habitat for at-risk salmonids in the Boreal forest. Fisheries Management and Ecology 23: 489-502.

Site Locations of Assessed Stream Crossings, including (a) Simoneete, (b) Latronell and (c) Deep Valley watersheds in Alberta Canada.

Prioritization given: net habitat gain (a,d), number of barriers removed (c,f) and the mean cost per barrier (c,f) across Deep Valley and Latronell subwatersheds.

Also Read:

Medinski, N.A.*, Maitland, B.M.*, Jardine, T.D., Drake, D.A.R. and M.S. Poesch (2022) A catastrophic coal mine spill in the Athabasca River watershed induces isotopic niche shifts in stream biota including an endangered rainbow trout ecotype. Canadian Journal for Fisheries and Aquatic Sciences 79(8): 1321-1334.

*Lab members: Bryan Maitland, Mark Poesch. Check out opportunities in the lab!

Neufeld, K.R. (2016) Improving our ability to assess the impacts of hydrologic alteration on stream fishes: An interdisciplinary approach to assess the Threatened Western Silvery Minnow Hybognathus argyritis in Canada

Thesis title: Improving our ability to assess the impacts of hydrologic alteration on stream fishes: An interdisciplinary approach to assess the Threatened Western Silvery Minnow Hybognathus argyritis in Canada

Author: Kenton Neufeld

Abstract

Human induced hydrologic alteration is ubiquitous in North American riverscapes. These alterations have been shown to impact fishes by modifying habitats, influencing movement patterns and driving changes in community structure. Understanding these impacts is an essential first step for the conservation of fish in these systems. We use Western Silvery Minnow Hybognathus argyritis and the Milk River of southern Alberta as a model system to develop and apply an interdisciplinary approach to assess the impacts of hydrologic alteration on capture efficiency and habitat suitability of stream fishes. The capture efficiency of sampling gear is a key component of many fish research programs, and understanding the link between hydrology and capture efficiency is critical to accurately assessing the impacts of hydrologic alterations on fish. We measured seine net capture efficiency in the Milk River, and investigated the effects of flow, species, and habitat variables on capture efficiency using mixed effects models. Flow state was an important driver of capture efficiency, which increased ~5 % during augmented flow compared to natural flow. Habitat suitability assessments are commonly used to determine the impacts of hydrologic alteration on fishes, but often rely on poorly understood relationships between fish and their habitat. We used the swimming performance of Western Silvery Minnow to measure the cost of movement between habitat patches in the Milk River and incorporated this cost into a graph theoretic metric of habitat suitability (Equivalent Connected Area). Compared to augmented flow, the proportion of suitable area was ~ 475 % higher during natural flow, the mean cost of movement between habitat patches was ~ 13 % higher and Equivalent Connected Area increased ~ 0.119 (95% C.I. 0.109-0.130). By including flow as a variable in modelling capture efficiency and swimming performance as a mechanism defining habitat suitability, we show the utility and benefits of taking an interdisciplinary approach to assessing the impacts of hydrologic alteration on stream fishes.

Veillard, M. (2016) Investigating fine-scale movement patterns and comparative swimming performance of the newly identified and threatened Rocky Mountain Sculpin (Cottus sp.) across its Canadian distribution

Thesis Title: Investigating fine-scale movement patterns and comparative swimming performance of the newly identified and threatened Rocky Mountain Sculpin (Cottus sp.) across its Canadian distribution

Author: Marie Veillard

Abstract

Cumulative anthropogenic impacts to the riverscape, including hydrologic alteration, have contributed to an escalated number of freshwater fish species at risk in North America. Species dispersal is an important mechanism underlying many ecological processes. Understanding the scale at which species carry out their life history can inform both conservation actions and recovery potential. Our study used the recently-identified Rocky Mountain Sculpin (Cottus sp.), a species federally listed as threatened, to investigate the (1) fine-scale movement potential and (2) comparative swimming ability of adults throughout their restricted Canadian distribution. Rocky Mountain Sculpin are a small-bodied, cryptic benthic species that utilizes interstitial spaces for shelter. To assess the fine-scale movement potential of Rocky Mountain Sculpin, I conducted a mark-recapture study on Lee Creek, Alberta using Passive Integrated Transponder (PIT) and Visible Implant Elastomer (VIE) tags. I assessed the abiotic and biotic factors influencing movement using Boosted Regression Tree models. In this study I found that 89% of sculpins moved less than 30 meters, while a few individuals moved up to 240 meters. Biotic factors indicated sculpins moved from high to low abundances of fish due to intra- and inter- specific competition from congeners and benthic competitors. The most important abiotic factor contributing to movement was abundance of cobble substrate at destination transects. Interestingly, there was a strong interaction between biotic and abiotic components indicating the importance of focusing restoration efforts on both biotic and abiotic factors. To address the second objective, comparative fish swimming performance and recovery potential was assessed in a laboratory on individuals sourced from drastically different hydrologic regimes in Alberta and British Columbia, including the flow augmented, North Milk River. Permutational ANOVAs were used to compare swimming performance between rivers using two aspects of swimming ability: (1) slip velocity, the point at which fish slipped and transitioned into swimming and 2) failure velocity, the point at which fish could no longer hold position against the flow without resting. While we expected swimming ability to be correlated with natal hydrologic regimes, our study found there were no differences in failure or slip velocity between rivers. However, resting oxygen uptake prior to swim tests was significantly higher for fish from the augmented, North Milk River, indicating there may be a physiological response to flow augmentation. Over repeated exercise, fish failure velocity decreased from 7.45 ± 3.10 body lengths per second (BL s-1) in the first test to 6.18 ± 2.56 BL s-1 by the third test suggesting the use of anaerobic metabolism to power swimming performance of this small-bodied species. Linear mixed-effects models developed using body characteristics showed caudal morphology to influence both failure and slip velocities, while body height was negatively correlated to slip velocity, demonstrating morphological selection for benthic living. Taken together, these studies suggest that while large-scale flow augmentation may come at an energetic cost to sculpins, fine-scale developments may be equally as detrimental to this dispersal-limited species. Conservation for this species may then require both fine-scale and regional management.

Thayer, D. (2016) Identifying seasonal Lake Sturgeon (Acipenser fulvescens) movement patterns and habitat selection in the South Saskatchewan River Basin

Thesis Title: Identifying seasonal Lake Sturgeon (Acipenser fulvescens) movement patterns and habitat selection in the South Saskatchewan River Basin

Author: Donnette Thayer

Abstract

Lake Sturgeon (Acipenser fulvescens Rafinesque 1817) have experienced population declines throughout their range. In Alberta, low density age-class distributions, irregular recruitment, critically low spawning potential ratios and other factors led to a 2007 designation of “Threatened” for this species under the Provincial Wildlife Act. As a protected species, efforts to develop a comprehensive recovery strategy require an understanding of species’ biology, behavior, and critical habitat requirements. My objectives were to a) identify movement behaviors and habitat changes before and after an extreme flood event, and b) ascertain overwintering movement behaviors and habitat selection of South Saskatchewan River Basin Lake Sturgeon. Multiple-receiver acoustic telemetry was used to obtain triangulated, fine-scale movement patterns at the confluence of the Bow and Oldman rivers, a potential critical spawning habitat site, before, during and after an extreme flood, and at a study site on the South Saskatchewan River known to be critical overwintering habitat, before, during, and after the ice-on period. Substrate analysis was performed pre- and post-flood for Grand Forks, and substrate, bottom velocity, and depth analyses were performed for the South Saskatchewan River overwintering study site. In the extreme flood event study, movement behaviors were captured by receivers positioned to triangulate movements and provide positions at a fine scale. Receivers had been deployed to assess spawning behavior when the 2013 Alberta ‘Flood of Floods’ occurred, providing an opportunity to document fine-scale Lake Sturgeon movement behaviors before, during and after an extreme disturbance event. Lake Sturgeon showed a tendency to avoid high water velocity areas. Increases in flow rate showed a significant negative relationship to mean positional distance from shore. Substrate assessment prior to and following the flood showed a significant change in substrate composition. Mean gravel- and larger-substrate area increased, providing evidence that high flow rates in 2013 and 2014 exposed larger particle fluvial substrate. Complexity as measured by patch density increased, indicating a measureable overall increase in heterogeneity. Lake Sturgeon benefitted from improved spawning habitat following the extreme flood by gaining larger, cleaner substrate with more complexity. Although extreme flood events may be costly to human life and infrastructure, they may be ecologically beneficial to some freshwater organisms, particularly plesiomorphic, long-lived species such as Lake Sturgeon whose survival has depended upon a capability to adapt to erratic and occasionally extreme peak flow events. In the overwintering study, fine-scale movements by adult and juvenile Lake Sturgeon were tracked for a previously identified overwintering habitat in the South Saskatchewan River using acoustic telemetry from late October 2013 through April 2014 for a 1.5 kilometer reach of the South Saskatchewan River identified in a previous study as overwintering habitat. Period-segmented movement rates, depth selection, aggregation behavior and preferential overwintering habitat selection by adult and juvenile Lake Sturgeon were evaluated for 23-26 individuals (20-23 adults and 3 juveniles, depending on residency during period assessed – individuals not present during all segments were excluded) detected within the study area. Environmental parameters included depth, depth standard deviation (rugosity), bottom velocity, bottom velocity standard deviation, and substrate type (silt, sand, and gravel or larger substrate). Boosted regression tree (BRT) analyses were performed to identify habitat selection for Lake Sturgeon for period-aggregated core (50th percentile) and range (95th percentile) positions. Movement rates paralleled temperature variation, becoming highly restricted during periods of deepest cold. Increased aggregation was also noted for these periods. The deepest habitat positions occurred during ice formation and breakup. Depth and bottom velocity were the most important variables used to identify sturgeon habitat for all periods assessed. Since Lake Sturgeon display site fidelity and aggregation behaviors independent of resource availability, winter habitat may limit the population. While spawning habitat is crucial to ensuring successful recruitment, data suggests that a substantial portion of the population spends the greater part of the year in overwintering locations, making this habitat potentially more critical to the survival of the population as a whole than any other habitat. If winter habitat is degraded or otherwise compromised, it could hinder species recovery, and should be considered critical habitat, receiving appropriate protection. This was the first study to use fine-scale acoustic telemetry analysis of movement behavior and habitat selection for a Lake Sturgeon population occupying fluvial winter habitat.

Neufeld, K.*, Blair, S., and Poesch, M.S. (2015) Retention and stress effects of visible implant tags when marking Western Silvery Minnow Hybognathus argyritis and its application to other cyprinids (family Cyprinidae). North American Journal of Fisheries Management 35: 1070-1076.

Abstract:

Visible implant tags are commonly used in fisheries research to mark individuals or batches of fish as part of movement and mark–recapture studies. To be effective, these tags generally need to have high retention rates and little impact on the behavior or physiology of the marked individuals. We tested the retention rates of both visible implant elastomer (VIE) and visible implant alphanumeric (VIA) tags in 80–139-mm Western Silvery Minnow Hybognathus argyritis over a 104-d period. We also measured plasma cortisol and lactate to determine the impact of tagging on stress levels. We found that VIE tags had 100% retention and did not cause a significant increase in plasma cortisol levels, though plasma lactate levels were elevated in VIE treatment groups. Overall, VIE tags were found to be suitable for marking Western Silvery Minnow and similar species. Visible implant alphanumeric tags had 36% retention over 104 d and did not cause significant increases in plasma cortisol, though plasma lactate was elevated in the treatment group with both VIE and VIA tags. Given the high retention rates and low stress effects, VIE tags appear to be more beneficial for use with Western Silvery Minnow and similar-sized cyprinids.

Citation: Neufeld, K.*, Blair, S., and Poesch, M.S. 2015. Retention and stress effects of visible implant tags when marking Western Silvery Minnow Hybognathus argyritis and its application to other cyprinids (family Cyprinidae). North American Journal of Fisheries Management 35: 1070-1076.

Average Western Silvery Minnow (a) plasma cortisol and (b) plasma lactate concentrations for the various tagging treatments (VIE – Visual Implant Elastomer, VIA – Visual Implant Alpha, VIE+VIE – both) for days 1, 54 and 103/104. Error bars represent SD.

Also Read:

Fischer, S.M.*, Ramaza, P., Simmons, S., Poesch, M.S. and M.A. Lewis. (2023) Boosting propagule transport models with individual-specific data from mobile apps. Journal of Applied Ecology 60(5): 934-949.

*Lab members: Kenton Neufeld, Mark Poesch. Check out opportunities in the lab!

Poesch, M.S., Lawrie, D., Tu, C., Jackson, D.A., and N.E. Mandrak (2012) Developing local and regional population estimates for an endangered freshwater minnow, the redside dace (Clinostomus elongatus), in Canada. Aquatic Conservation 22: 47-57.

Abstract:

The Laurentian Great Lakes have undergone drastic declines in freshwater fishes, with 22 species having become extinct in the past century and many more currently at risk. One such species is the endangered minnow, the redside dace (Clinostomus elongatus), which is undergoing severe declines across its entire range. Depletion and mark–recapture surveys were used to quantify population estimates of redside dace at several spatial scales (pool, reach and catchment) across several Great Lakes tributaries in Canada. There was large variation in the local population estimates and the rate of occurrence of redside dace populations. In some cases, such as Gully Creek, a Lake Huron tributary, redside dace were widespread (9/10 of pools) but in low abundances (13.5 individuals per pool ± 5.09 ). In other cases, such as in the Don River, redside dace were highly localized (2/27 pools) but in relatively high abundance (99.2 individuals/pool ± 18.1). Extrapolated population estimates at the catchment scale showed that three of the five study populations were below conservative estimates needed for long-term population viability. Differences in redside dace populations were driven by adjacent land-use. Post-hoc analyses revealed strong negative associations between population estimates and impervious land-use (i.e. urbanization) at both the pool and sub-catchment level. Immediate recovery actions that will focus on eliminating chronic and episodic impacts of adjacent land-use and improve connectivity are needed to help ensure redside dace, like many freshwater species in the Laurentian Great Lakes, remain a species at risk of – rather than facing – extinction.

Citation: Poesch, M.S., Lawrie, D., Tu, C., Jackson, D.A., and N.E. Mandrak. 2012. Developing local and regional population estimates for an endangered freshwater minnow, the redside dace (Clinostomus elongatus), in Canada. Aquatic Conservation 22: 47-57.

Also Read:

Neufeld, K.*, Watkinson, D., and Poesch, M.S. (2016) The effect of hydrologic alteration on capture efficiency of freshwater fishes in a highly modified Prairie stream: Implications for bio-monitoring programs. River Research and Applications 32: 975-983.

Schwalb, A.J., Cottenie, K., Poesch, M.S., and J. Ackerman (2011) Dispersal limitation in unionid mussels and implications for their recovery. Freshwater Biology 56: 1509-1518.

Abstract:

Freshwater unionid mussels are a highly imperilled group. Their dispersal abilities depend on the availability and the movement of host fish on which their parasitic mussel larvae develop. We examined the relationship between the dispersal abilities of unionid mussels and their conservation status on a regional (SW Ontario) scale and their distribution and abundance on a catchment scale (Sydenham River, SW Ontario) by determining host specificity and estimating the dispersal abilities of mussels on fish from a review of the literature. On the regional scale, we found that mussels with the most precarious conservation status relied on host fish with short movement distances, whereas vulnerable and more secure mussel species had host fish with 2–3 orders of magnitude larger movement distances. We were not able to detect a clear pattern on the catchment scale. Our results suggest that limited dispersal by host fish affects the abundance and distribution of unionid mussels and ultimately their conservation status on a regional scale. Information on dispersal limitations because of differences in host fish communities should be included in conservation and management decisions to ensure connectivity and maintain functioning mussel metacommunities.

Citation: Schwalb, A.J., Cottenie, K., Poesch, M.S., and Ackerman, J. 2011. Dispersal limitation in unionid mussels and implications for their recovery. Freshwater Biology 56: 1509-1518.

Also Read:

Maitland, B.M.*, Anderson, A. and Poesch, M.S. (2016) Prioritising culvert removals to restore habitat for at-risk salmonids in the Boreal forest. Fisheries Management and Ecology 23: 489-502.

Schwalb, A.J., Poesch, M.S., and J. Ackerman (2011) Movement of logperch—the obligate host ﬁsh for endangered snuffbox mussels: implications for mussel dispersal. Aquatic Sciences 73: 223-231.

Abstract:

Unionid mussels are highly imperiled and the survival of their local populations is linked to the availability and dispersal potential of their host fish. We examined the displacement distance of logperch (Percina caprodes), which are obligate host fish for endangered snuffbox mussels (Epioblasma triquetra), to determine the dispersal potential by fish. Logperch in the Sydenham River, Ontario, Canada, were electrofished and marked with visible implant elastomer on five sampling dates during the gravid period of E. triquetra. The majority of all recaptures (82%) of P. caprodes occurred within 30 m of their original capture location, with a mean displacement distance of 13 ± 3 m (mean ± standard error, n = 28). These results were consistent with a review of movement studies of small benthic host fish (i.e., darters and sculpins), which revealed average fish displacement distances of 37 ± 19 m (n = 14 species; range: 4–275 m). However, significantly greater movement distances were also found and the maximum displacement distance increased significantly with the spatial extent of the study and with the duration of the study. These results indicate that many P. caprodes remain in a small area, which could restrict the dispersal and (re)colonization potential of E. triquetra. Further studies are needed to determine the dispersal potential of mussels via host fish, which may be important for maintaining the connectivity among unionid populations.

Citation: Schwalb, A.J., Poesch, M.S., and Ackerman, J. 2011. Movement of logperch—the obligate host ﬁsh for endangered snuffbox mussels: implications for mussel dispersal. Aquatic Sciences 73: 223-231.

Also Read:

Veillard, M.F.*, Ruppert, J.L.W.*, Tierney, K., Watkinson, D., and M.S. Poesch. (2017) Comparative swimming and station-holding ability of the threatened Rocky Mountain Sculpin (Cottus sp.) from four hydrologically distinct rivers. Conservation Physiology 5: 1-12.