Freshwater residualism in coho salmon
March 31, 2017
Evidence for freshwater residualism in coho salmon, Oncorhynchus kisutch, from a watershed on the north coast of British Columbia
Eric A. Parkinson, Chris J. Perrin, Daniel Ramos-Espinoza, Eric B. Taylor
The Coho Salmon, Oncorhynchus kisutch, is one of seven species of Pacific salmon and trout native to northeastern Pacific Ocean watersheds. The species is typically anadromous; adults reproduce in fresh water where juveniles reside for 1–2 years before seaward migration after which the majority of growth occurs in the ocean before maturation at 2–4 years old when adults return to fresh water to spawn. Here, we report maturation of Coho Salmon in two freshwater lakes on the north coast of British Columbia apparently without their being to sea. A total of 15 mature fish (11 males and four females) were collected in two lakes across two years. The mature fish were all at least 29 cm in total length and ranged in age from three to five years old. The occurrence of Coho Salmon that have matured in fresh water without first going to sea is exceedingly rare in their natural range, especially for females. Such mature Coho Salmon may represent residual and distinct breeding populations from those in adjacent streams. Alternatively, they may result from the ephemeral restriction in the opportunity to migrate seaward owing to low water levels in the spring when Coho Salmon typically migrate to sea after 1–2 years in fresh water. Regardless of their origin, the ability to mature in fresh water without seaward migration may represent important adaptive life history plasticity in response to variable environments.
Causes and consequences of straying
March 27, 2017
Causes and consequences of straying into small populations of Pacific salmon
Nolan N. Bett, Scott G. Hinch, Nicholas J. Burnett, Michael R. Donaldson, Sean M. Naman
Most Pacific salmon Oncorhynchus spp. migrate to their natal sites to spawn. Some, however, stray into nonnatal habitats and interact (e.g., reproduce) with individuals from other populations. Pacific salmon straying has been heavily studied for several decades, particularly from the perspective of the populations that donate the stray migrants. Conservation consequences are experienced primarily by the populations that receive strays, though, and there is recent evidence of significant levels of genetic introgression in small recipient populations, which could contribute to the loss of local adaptations. Straying may also provide the benefit of a demographic rescue effect that could save declining recipient populations from extirpation. We highlight the influence of population abundances on the magnitude of straying into recipient populations and demonstrate this using evidence we collected from a small population of Sockeye Salmon O. nerka in British Columbia, Canada. We also review potential factors that might promote higher donor stray rates and therefore recipient straying. Evidence of factors that affect straying is limited and we identify several knowledge gaps, as well as anthropogenic activities that could promote straying. We encourage further discussion and research on the potential effects of recipient straying and the factors that affect straying rates.
IFR deploy first Vaki Riverwatcher counter in western Canada
November 17, 2016
IFR is collaborating with Vaki, Fisheries and Oceans Canada and Metro Vancouver to test a Riverwatcher optical beam counter at the Cariboo Dam in Burnaby, BC. IFR will be counting chum and coho salmon, and steelhead trout from November 2016 to March 2017.
The Riverwatcher is triggered when a beam of light is broken by a fish passing through the unit, creating a silhouette image of each fish. Once the counter registers an up or down count, the passage event is recorded by an underwater camera unit. IFR will be examining whether silhouette images and video footage can be used to determine species and hatchery origin (adipose fin present or absent).
(Left) 79 cm wild (adipose fin present) chum salmon. (Right) 69 cm hatchery (adipose fin absent) coho salmon.
The Riverwatcher counter is directly linked to a website, Riverwatcher Daily, that provides daily summaries of up and down counts past the counter. More detailed summaries (size distribution and migration timing) are provided here.
No respect for the spineless
July 26, 2016
Taxonomic bias and international biodiversity conservation research
Michael R. Donaldson, Nicholas J. Burnett, Douglas C. Braun, Cory D. Suski, Scott G. Hinch, Steven J. Cooke, Jeremy T. Kerr
While greater research on threatened species alone cannot ensure their protection, understanding taxonomic bias may be helpful to address knowledge gaps in order to identify research directions and inform policy. Using data for over 10 000 animal species listed on the International Union for Conservation of Nature Red List, we investigated taxonomic and geographic biodiversity conservation research trends worldwide. We found extreme bias in conservation research effort on threatened vertebrates compared with lesser-studied invertebrates in both terrestrial and aquatic habitats at a global scale. Based on an analysis of common threats affecting vertebrates and invertebrates, we suggest a path forward for narrowing the research gap between threatened vertebrates and invertebrates.
Mitigating carryover effects of dam passage
July 12, 2016
Reducing carryover effects on the migration and spawning success of sockeye salmon through a management experiment of dam flows
Nicholas J. Burnett, Scott G. Hinch, Nolan N. Bett, Douglas C. Braun, Matthew T. Casselman, Steven J. Cooke, Ahmed Gelchu, Stephanie Lingard, Collin T. Middleton, Vanessa Minke‐Martin, Carson F.H. White
Effective dam management requires an understanding of the ecological impact of a facility and its operations on individual fish and fish populations. Traversing high flows downstream of dams is an energetically challenging activity that could influence survival and spawning success following passage. Carryover effects, however, are an underappreciated consequence of dam passage that have been overlooked by researchers and natural resource managers. We conducted a large-scale management experiment to determine if the operation of dam attraction flows could be changed to reduce high sockeye salmon Oncorhynchus nerka mortality following passage and increase spawning success. We tested two flow conditions: (i) a baseline condition—currently used by managers—that released high attraction flows directly adjacent to the entrance to a vertical-slot fishway and (ii) an alternative condition that released attraction flows 10 m away from the fishway entrance to reduce the flows fish swim through while approaching the passage structure. We tagged 637 sockeye salmon with telemetry tags to monitor dam passage, post-passage survival to spawning grounds and spawning success under the two flow conditions. Validated fish counters at the exit of the fishway and on spawning grounds were used to generate population level estimates of survival to spawning grounds. Individuals exposed to baseline flow conditions spent two times longer recovering from dam passage and exhibited 10% higher mortality following passage than those exposed to alternative flows. Release of alternative flows for 10 days assisted approximately 550 fish (or 3% of total spawners) in reaching spawning grounds. Once on spawning grounds, female spawning success was strongly influenced by individual spawning characteristics (longevity and date of arrival on spawning grounds) and not dam flow condition. Our findings highlight a cost-effective solution that decreases mortality following passage simply by altering the location of dam flow releases and not reductions in discharge.
Egg size and parity in salmon
June 1, 2016
Costs of reproduction can explain the correlated evolution of semelparity and egg size: theory and a test with salmon
Holly K. Kindsvater, Douglas C. Braun, Sarah P. Otto, John D. Reynolds
Species’ life history traits, including maturation age, number of reproductive bouts, offspring size and number, reflect adaptations to diverse biotic and abiotic selection pressures. A striking example of divergent life histories is the evolution of either iteroparity (breeding multiple times) or semelparity (breed once and die). We analysed published data on salmonid fishes and found that semelparous species produce larger eggs, that egg size and number increase with salmonid body size among populations and species and that migratory behaviour and parity interact. We developed three hypotheses that might explain the patterns in our data and evaluated them in a stage-structured modelling framework accounting for different growth and survival scenarios. Our models predict the observation of small eggs in iteroparous species when egg size is costly to maternal survival or egg number is constrained. By exploring trait co-variation in salmonids, we generate new hypotheses for the evolution of trade-offs among life history traits.
Marine Scotland Science publishes IFR technical review of counters
March 22, 2016
IFR conducted a comprehensive technical review of electronic counter technologies for Marine Scotland Science to inform the development of a counter network for Scotland. Click here for the review.
Nich Burnett conducts research on catfish in the Amazon
January 4, 2016
Nich Burnett recently worked in Brazil on the Xingu River to conduct research on catfish with Dr. Lisiane Hahn and her team from Neotropical Consultoria Ambiental.
The Xingu is the largest clearwater tributary of the Amazon that is nearly twice the length of the Fraser River. With a complex system of braided channels, the Xingu has an extreme hydrological cycle – discharge ranges from 500 m3/s in the dry season to over 30,000 m3/s in the rainy season. More than 600 fish species are found in the Xingu, many of which are endemic and adapted to the powerful rapids of Volta Grande – “Great Bend” – a 100 km section of river that takes three 90 degree turns and drops 90 meters in elevation. Travelling to the Xingu River is not for the impatient – it takes 24 hours and three or more flights from southern Brazil.
Recent hydropower development in the Xingu River, however, has raised concerns about the impact of infrastructure on native fish communities. Various species of catfish are of particular concern as they are a significant food source for local communities and are commercially valuable as ornamental fish. Basic biological information on these species does not exist, representing a significant knowledge gap to understanding anthropogenic impacts on populations.
Hahn and Burnett collected fundamental biological, behavioural and physiological information from catfish, and developed tests to surgically implant electromyogram (EMG) radio transmitters into fish to monitor muscle recruitment while swimming in an open-channel flume.
Fish tagged with EMG transmitters in future projects will experience a range of flows downstream of dams and within fishways, later transmitting data on swimming behaviour to fixed receiver stations. Validation of EMG tags in catfish will aid Neotropical Consultoria Ambiental in understanding the response of catfish to changes in flow surrounding hydropower infrastructure, and will provide ecological context for the responsible management of flows in fishways in the Amazon.
Cost-effective temperature monitoring
June 27, 2015
Using watershed characteristics to inform cost-effective stream temperature monitoring
Douglas C. Braun, John D. Reynolds, David A. Patterson
Water temperature is a key driver of aquatic processes. Monitoring stream water temperature is key to understanding current species distributions and future climate change impacts on freshwater ecosystems. However, a very small fraction of streams are continuously monitored for water temperature throughout North America, due to prohibitive logistical costs. We develop a framework that aids in developing cost-effective stream temperature monitoring by using stream habitat features to inform strategic site selection of temperature monitoring sites. We test this framework using sockeye salmon spawning streams as a model, which included 19 streams in the northern-most watershed of the Fraser River Basin, British Columbia, Canada. The objective of this framework is to evaluate the trade-off between cost (i.e., the number of streams monitored) and the effectiveness of monitoring scenarios at meeting different monitoring objectives. We compared monitoring scenarios that were informed by well-established relationships between variables and that are commonly collected or available as part of other monitoring activities (stream length, magnitude, order, gradient, wetted width, and spot temperatures) and water temperature metrics (maximum, mean, and variance during August) derived from continuously monitored streams to monitoring scenarios where streams were randomly selected. Informed scenarios included streams that were selected in order of watershed level and stream habitat characteristics (e.g., longest to shortest); ordering was based on the relationship between each habitat variable and temperature metrics. Informed monitoring scenarios were then compared to random selection of monitoring sites with regard to how well monitoring scenarios met two management objectives during the critical salmon spawning period: (1) identifying streams that exceed a temperature threshold and (2) identifying streams that represent the temperature regime of a complex of streams (e.g., mean and variance of streams within an aggregate of streams). Management objectives were met by monitoring fewer streams using the informed monitoring scenarios rather than the average of the random scenarios. This highlights how common inexpensive watershed level variables that relate to stream temperature can inform the strategic selection of sites and lead to more cost-effective stream temperature monitoring.
Population diversity in salmon
April 29, 2015
Population diversity in salmon: linkages among response, genetic and life history diversity
Douglas C. Braun, Jonathan W. Moore, John Candy, Richard Bailey
Response diversity and asynchrony are important for stability and resilience of meta-populations, however little is known about the mechanisms that might drive such processes. In salmon populations, response diversity and asynchrony have been linked to the stability of their meta-populations and the fisheries that integrate across them. We examined how population diversity influenced response diversity and asynchrony in 42 populations of Chinook salmon from the Fraser River, British Columbia. We examined diversity in the survival responses to large-scale ocean climate variables for populations that differed in life history. Different life-histories responded differently to ocean environmental conditions. For instance, an increase of offshore temperature was associated with decreased survival for a population with ocean rearing juveniles but increased survival for a population with stream rearing juveniles. In a second analysis, we examined asynchrony in abundance between populations, which we then correlated with life history, spatial, and genetic diversity. Populations that were more genetically distant had the most different population dynamics. Collectively, these results suggest that fine-scale population diversity can contribute to the asynchrony and response diversity that underpins the stability of fisheries or metapopulation dynamics, and emphasize the need to manage and conserve this scale of population diversity.
Rivers as nature’s portfolios
April 5, 2015
Emergent stability in a large, free-flowing watershed
Jonathan W. Moore, Michael P. Beakes, Holly K. Nesbitt, Justin D. Yeakel, David A. Patterson, Lisa A. Thompson, Corey C. Phillis, Douglas C. Braun, Corinna Favaro, David Scott, Charmaine Carr-Harris, William I. Atlas
A new study, contributed to by IFR’s Douglas Braun, proposes and tests the hypothesis that rivers can act like diverse stock portfolios that dampen variability. Large free-flowing rivers naturally aggregate upstream diversity, which can confer stability just like a well-balanced financial stock portfolio.
Moore and his SFU team of postdoctoral researchers and graduate students as well as Fisheries and Oceans collaborators compiled and analyzed an enormous dataset of fisheries catches, water flows, and water temperatures from sites located throughout the Fraser River. In total, they compiled 30 years of data from a total of 142 sites from throughout this > 220,000 square kilometer watershed.
Sites that drained larger catchments had more stable flows, temperatures, and fisheries, with less frequent fisheries crashes and floods. While rivers are well known for their variable flows and channel dynamics, this study suggests that rivers would be vastly more unpredictable and variable without this stabilization.
Char and salmon migrations in warming waters
January 12, 2015
A new study in one southeast Alaska drainage finds that the migration of predatory char has remained in synch with Pacific salmon that have changed their migration patterns due to a warming climate. It is one of the first documented instances where migratory predator and prey have remained in synch in the face of climate change-induced phenology changes. Read more.
IFR Level 1 Habitat training
October 30, 2014
IFR worked this summer with the City of Coquitlam, Metro Vancouver, the Coquitlam River Watershed Roundtable and BCIT to do a Level 1 Habitat Survey on the Lower Coquitlam River. A short promotional video was produced by the Coquitlam River Watershed Roundtable.
BC releases five-year plan to protect species at risk
July 29, 2014
Protecting Vulnerable Species: A Five-Year Plan for Species at Risk in British Columbia is a strategic document that sets out those high-level management actions that British Columbia plans to take over the next five years to improve management of species at risk in B.C. while balancing the province’s economic, environmental and social priorities.
BC professional scientists issue climate change statement
July 10, 2014
Associations representing more than 9,000 forest professionals, biologists and planners have issued a joint statement recognizing that “climate change is occurring and it has fundamental impacts on British Columbia’s communities and ecosystems.”
New journal papers
June 30, 2014
Two recent peer-reviewed publications feature IFR staff members as contributing authors. Please contact IFR if you wish to receive a PDF copy of these papers.
Marine survival difference between wild and hatchery-reared steelhead trout determined during early downstream migration
Michael C. Melnychuk, Josh Korman, Stephen Hausch, David W. Welch, Don J. McCubbing, and Carl J. Walters.
We observed large survival differences between wild and hatchery-reared steelhead trout (Oncorhynchus mykiss) during the juvenile downstream migration immediately after release, which persisted through adult life. Following a railway spill of sodium hydroxide into the Cheakamus River, British Columbia, a short-term conservation hatchery rearing program was implemented for steelhead. We used acoustic telemetry and mark–recapture models to estimate survival of wild and (or) hatchery-reared steelhead during 4 years of the smolt migration, with both groups released in 2008. After adjusting for estimated freshwater residualization, 7%–13% of wild smolts and 30%–40% of hatchery smolts died in the first 3 km of the migration. Estimated survival from release to ocean entry was 71%–84% for wild fish and 26%–40% for hatchery fish and to exit from the Strait of Georgia system was 22%–33% for wild fish and 3.5%–6.7% for hatchery fish. A calculated 2.3-fold survival difference established during the downstream migration was similar to that after the return of adult spawners, as return rates were 8.0% for wild fish and 4.1% for hatchery fish. Contrary to current understanding, a large proportion of salmon mortality in the smolt-to-adult period, commonly termed “marine mortality”, may actually occur prior to ocean entry.
Burst swimming in areas of high flow: delayed consequences of anaerobiosis in wild adult sockeye salmon
Nicholas J. Burnett, Scott G. Hinch, Douglas C. Braun, Matthew T. Casselman, Collin T. Middleton, Samantha M. Wilson Steven J. Cooke.
Wild riverine fishes are known to rely on burst swimming to traverse hydraulically challenging reaches, and yet there has been little investigation as to whether swimming anaerobically in areas of high flow can lead to delayed mortality. Using acoustic accelerometer transmitters, we estimated the anaerobic activity of anadromous adult sockeye salmon (Oncorhynchus nerka) in the tailrace of a diversion dam in British Columbia, Canada, and its effects on the remaining 50 km of their freshwater spawning migration. Consistent with our hypothesis, migrants that elicited burst swimming behaviors in high flows were more likely to succumb to mortality following dam passage. Females swam with more anaerobic effort compared to males, providing a mechanism for the female-biased migration mortality observed in this watershed. Alterations to dam operations prevented the release of hypolimnetic water from an upstream lake, exposing some migrants to supraoptimal, nearlethal water temperatures (i.e., 24 degrees C) that inhibited their ability to locate, enter, and ascend a vertical-slot fishway. Findings from this study have shown delayed post–dam passage survival consequences of high-flow-induced burst swimming in sockeye salmon. We highlight the need for studies to investigate whether dams can impose other carryover effects on wild aquatic animals.
Canadian sojourn helps to shake off Japan malaise
April 25, 2014
C.W. Nicol, active environmentalist, addresses issues such as deforestation and the preservation of natural environments. During a recent visit to Canada he recharged his environmental batteries.
“I grieve when I think how there were thousands of salmon rivers in Japan, from northern Kyushu to Hokkaido — but almost all of them have been ruined by pollution, dams and concrete. If Japan ever woke up and put its boundless energy to nature restoration, this country could be a very special place indeed.”
Record sockeye run in 2014?
March 6, 2014
Again, the pundits (or the forecasters) are forecasting record runs of sockeye salmon in the Fraser this summer. An excellent 2012 brood year and good ocean survival appear to be the basis for the positive outlook. Read more.