Climate change has already dramatically altered many inland waters through a combination of warming water, changes in phenology, and alterations to aquatic food webs. All of these forces can alter the growth, reproduction, survival, and behavior of fishes. Because these changes can influence fishes’ complex interactions with their habitat, predators, prey, and competitors, climate change can cause shifts in fish community composition that are difficult to prevent or reverse. Yet fishes also have the capacity to adapt to a changing environment through, for example, use of thermal refugia or changes in diet and habitat use. These adaptations may buffer the direct effects of climate change on fish populations, but may also involve trade-offs - e.g., thermal refugia may have few prey resources. For fish species targeted by recreational, commercial, Tribal, or subsistence fisheries, changes in fishing behaviors may further challenge our ability to understand and predict climate change impacts. For example, as many coolwater fishes face climate-driven declines in productivity, will fishers switch to targeting warmwater species and thus provide coolwater species with a compensatory reduction in fishing mortality? And how might managers encourage and leverage such stabilizing social-ecological feedbacks in order to confer greater resilience on harvested fish populations under climate change?
This session will integrate research from a broad range of disciplinary perspectives seeking to understand the impacts of climate change on inland fish and fisheries. We welcome submissions focused on all mechanisms by which climate change is altering the biology, ecology, or fisheries of inland fishes. We also welcome talks that address management of inland fisheries under climate change and the social or economic consequences of climate change impacts.
Lead Organizer: Olaf Jensen, Center for Limnology, University of Wisconsin-Madison (olaf.p.jensen@gmail.com)
Co-organizers:
Ashley Trudeau, Center for Limnology, University of Wisconsin-Madison (ashley.trudeau@gmail.com)
Zachary Feiner, Center for Limnology, University of Wisconsin-Madison and Wisconsin Department of Natural Resources (Zachary.Feiner@wisconsin.gov)
Presentations
02:00 PM
Response diversity among tributaries with variable flow permanence patterns buffers salmonid spawning habitat availability to interannual snowpack variation (8363)
Primary Presenter: Timothy Walsworth, Utah State University (timothy.walsworth@usu.edu)
Intermittent tributaries can support spawning activities of native fishes if they flow long enough and warm enough for offspring to develop and access perennial habitats. As climate change alters streamflow permanence patterns, it is critical to understand how this may impact the availability of spawning habitats to native fishes. Here, we describe the spatio-temporal variability in annual spawning suitability of intermittent and perennial tributaries in an Intermountain West river basin, and how these conditions are impacted by watershed physiographic and annual climatic conditions. We assessed spawning suitability of tributaries as the window of days during which the eggs of spawning individuals would be able to accumulate sufficient degree days to hatch and emerge before the stream dried or the growing season ended. In the low snowpack year, suitable spawning habitat was concentrated in perennial tributaries, as intermittent streams did not support sufficient surface flows. However, in a subsequent high snowpack year, intermittent tributaries provided extensive suitable spawning habitat, while perennial tributaries demonstrated reduced suitability due to cold temperatures. Importantly, the total suitable spawning window across the basin remained relatively constant between years, as suitability gains in intermittent tributaries balanced the losses in perennial tributaries. Our results highlight how the interaction between flow duration and temperature complicates predictions about how increased intermittency under climate change can be expected to impact native fishes.
02:15 PM
A LACK OF CRACKS: SPAWNING HABITAT DEGRADATION AND CLIMATE CHANGE THREATENS COREGONINE POPULATIONS (8365)
Primary Presenter: Brian Weidel, USGS (bweidel@usgs.gov)
Like many cold water fishes, conservation concerns for whitefishes (subfamily Coregoninae) continue to increase across their global range. We describe results from Lake Ontario that suggest spawning habitat degradation and changing winter conditions are likely impeding population growth. Cisco, Coregonus artedi, and Lake Whitefish, Coregonus clupeaformis, experience sporadic year-class success while abundances have declined for centuries. Spawning historically occurred lake-wide but is now confined to northern regions where ice forms most consistently. Egg deposition patterns indicate spawning (December) is targeted over shallow areas (2 – 5 m), where hard substrates with limited interstices (rock, dressenid mussels, dead shells) are still available. Habitats with interstices are rare due to centuries of sedimentation from land use, eutrophication, and now shells embedding interstices. Many eggs are dispersed by waves into deeper, soft sediments, but emergence traps find larvae only hatch from shallow, hard substrates. When we added clean rock to a degraded spawning site, egg incubation success increased 40 times relative to control sites. We suggest sedimentation has slowly reduced coregonine reproductive success by affecting the amount, quality, and distribution of habitats that can incubate eggs over winter. Shallow-deposited eggs require early forming ice to protect them, but ice cover has, and continues to, decline. Spawning habitat remediation may be needed in Lake Ontario and similar ecosystems, to conserve or restore lithophilic-spawning fish populations.
02:30 PM
THE BAD RECRUITMENT PARADIGM: A NEW LENS ON CISCO POPULATION DYNAMICS AMIDST WEATHER EXTREMES (8167)
Primary Presenter: Olivia Nyffeler, University of Minnesota Twin Cities (nyffe008@umn.edu)
Cisco (coregonus artedi) were once abundant in the Great Lakes, but populations have declined due to overfishing, invasive species, and climate change. Cisco were extirpated in many of the Great Lakes, but populations in Lake Superior are gradually on the rise. However, Lake Superior’s population and commercial harvest are supported by a handful of successful year classes, and recruitment patterns are erratic and not well understood. Using the “Bad Recruitment Paradigm” we evaluate if weather extremes can lead to cisco recruitment failures. We used the catch per unit effort of age-1 Cisco from USGS bottom trawl surveys from 1978-2023 as an index of recruitment. During this time period “boom” years were defined as those with recruitment over 33 fish per ha swept, with remaining years characterized as “bad”. From publicly available sources, we collected data on wind speed, air temperature, and ice cover and in critical development periods to evaluate the correlation between weather extremes and poor recruitment years. Findings reveal that warmer air temperatures in May, June, November, and December, and cooler temperatures in August and September, typically lead to poor cisco recruitment. By linking recruitment to weather extremes, this paradigm could make it possible to anticipate years with poor recruitment, offering valuable insights for Great Lakes Cisco populations and enhancing resilience against climate change.
02:45 PM
Vertical distribution of cold-water fishes skewed toward anoxic bottom layer (7884)
Primary Presenter: Ryosuke Katayose, National Institute for Environmental Studies (NIES) (shakeyose.0910@gmail.com)
The suitable habitat for cold-water fishes require both a low water temperature and sufficient dissolved oxygen concentration (DO), typically reported below 13 degrees Celsius and above 3 mg/L for salmonids. In temperate lakes, prolonged high-water temperatures limit the vertical distribution of the cold-water fishes at the surface layer, while anoxic conditions limits the vertical distribution at the bottom layer, squeezing suitable habitats for the cold-water fishes. Thus, quantifying cold-water fishes vertical distribution dynamics would be vital to assess climate change impact on their populations in such lakes. Here, we surveyed seasonal dynamics of the vertical distribution of cold-water fish populations in a Japanese lake (Max depth = 13 m, Surface area = 12 km2) using acoustic exploration. We examined the relationship of the vertical fish distribution with water depth, temperature, and quality, finding many individuals at depths below 3 mg/L DO, considered unsuitable. Accordingly, the threshold of DO for the fish distribution identified by a statistical analysis from our data was significantly lower (0.46 mg/L) than reported in the literature. In contrast, the water temperature threshold was consistent with the literature's (13 degrees Celsius). This result suggests cold-water fishes respond differently in the field to the threshold of high-water temperatures and dissolved oxygen. Further examination of the underlying mechanisms generating these differences would provide insights into how cold-water fish select habitats and will be impacted under warming conditions.
03:00 PM
Seasonal variation of oxythermal habitat availability for cisco in southern-edge glacial lakes (7979)
Primary Presenter: Jelsie Kerr, Purdue University (kerrjj@purdue.edu)
Habitat suitability for lentic cold-water fish species may be partially constrained by water temperature and dissolved oxygen concentrations. With the progression of climate warming, challenges linked to these environmental conditions are likely to intensify, especially during the late-summer stratification period. In Indiana, USA, cold-water cisco (Coregonus artedi) have declined precipitously from occupying ~50 lakes in early 1900s, to presently only inhabiting six glacial lakes. Here, we evaluate the risk of extirpation of these remnant cisco populations a) by exploring variability in temperature and dissolved oxygen patterns to determine habitat suitability and b) by evaluating the sources of nutrient (phosphorous) loading to these lakes. We collected temperature and dissolved oxygen profiles from June to December 2023 and used various oxythermal thresholds to assess seasonal vertical habitat availability. Moreover, we applied L-THIA (Long Term Hydrological Impact Analysis) to estimate the dominant phosphorous loading sources to each lake. Our findings reveal notable declines in available oxythermal habitat between mid-September and mid-October, suggesting aggressive management interventions could target this time period. In the majority of lakes, row crop agriculture within the lake catchment appears to be the dominant source of phosphorous loading. Understanding oxythermal challenge periods for cisco and other cold-water species is essential to their management in a warming climate, particularly in the southern-most portions of their range.
03:15 PM
ADAPTIVE RESPONSES OF ANGLERS AND FISH TO CLIMATE CHANGE UNDERMINES COLDWATER FISHERY SUSTAINABILITY (8085)
Primary Presenter: Thomas Detmer, Cornell University (thomas.m.detmer@gmail.com)
Climate change inevitably will induce human responses to changing aquatic ecosystems. Angling is an economically, culturally, and nutritionally important activity throughout the world that depends both on human behavior and fish behavior. Coldwater fisheries may be especially vulnerable to impacts from climate warming as waters warm beyond thermally optimal temperatures. At the same time, anglers may target ecosystems that are perceived to offer higher catches given environmental conditions. We find that angler records from 10 lakes (1980-2019) show that shallow lakes with less thermal refugia for coldwater fish exhibited a steep decline in trip frequency at warmer temperatures; by contrast, the number of trips to deep lakes with more thermal refugia stabilized at moderate temperatures and increased at higher temperatures. In addition, catch per trip broadly declined in all lakes with increasing temperatures, but the rate of decline was higher in shallow lakes at warmer temperatures. Thus, total monthly catch declined with increasing temperature in shallower lakes but increased in deeper lakes. Although deeper lakes may provide thermal refugia for cold-water species due to greater availability of cold and oxygen-rich habitat, warming leads to elevated exposure to angling-related stressors. Our results show that a coldwater fishery undergoing warming is associated with shifting angler exploitation patterns that may enhance stress experienced by fish in climate refugia.
SS36B - Climate Change Impacts on Inland Fish and Fisheries
Description
Time: 2:00 PM
Date: 5/6/2024
Room: Hall of Ideas I