SFS Annual Meeting

Henry Baker (Primary Presenter/Author)
University of California, San Diego, hkbaker@ucsd.edu;

Abstract: The width of a population's resource use niche is determined by individual diet breadth (“within-individual component”) and the degree of niche partitioning between individuals (“between-individual component”). The balance between these two factors affects ecological stability and evolutionary trajectories, and may shift as ecological opportunity permits broader population niches. Lakes in California’s Sierra Nevada mountains vary in resource diversity for introduced Brook Trout (Salvelinus fontinalis) due to elevation, lake morphometry, and watershed features. We compared the relative contributions of within- and between-individual niche components to two measures of the dietary niches of thirteen populations of Brook Trout: prey taxonomic composition and prey size distribution. For both taxonomic and size diversity of fish diets, population niche width was positively related to both the within- and between-individual components. For taxonomic diversity, the two components increased in parallel, while for size diversity, the between-individual component became more important relative to the within-individual component in populations with the greatest niche widths. Our results support the Niche Variation Hypothesis that populations with broader niches are more heterogeneous, and show that individual niche width and individual specialization can operate in parallel to expand the population niche.

Belda MOSEPELE (Primary Presenter/Author)
Botswana University of Agriculture and Natural Resources, bmosepele@buan.ac.bw;

Ketlhatlogile MOSEPELE (Co-Presenter/Co-Author)
Botswana University of Agriculture and Natural Resources, kmosepele@buan.ac.bw;

Helen Dallas (Co-Presenter/Co-Author)
Freshwater Research Centre and Nelson Mandela Metropolitan University, helen@frcsa.org.za;

Keoikantse Sianga (Co-Presenter/Co-Author)
Botswana University of Agriculture and Natural Resources, ksianga@buan.ac,bw;

Montshwari Molefe (Co-Presenter/Co-Author)
Aquaculture Division, Ministry of Agriculture and Food Secuity, molfkin@outlook.com;

Abstract: Aquatic macroinvertebrates are a key component of primary production. Therefore, understanding their dynamics can contribute to knowledge of ecosystem dynamics in wetlands. Data used in this study were collected over one season in a seasonal floodplain of the Okavango Delta. Standardised sampling techniques were used to sample the aquatic macro-invertebrates. Multivariate and univariate techniques were used to assess their dynamics. 12846 specimens encompassing 49 families were collected during the study period. Corixidae, Coleoptera, Chironomidae, Planorbidae and Baetidae were the dominant groups in the assemblage, respectively. Chironomidae, Baetidae and Planorbidae populations fluctuated significantly (p<0.05) seasonally while Corixidae and Coleoptera populations had moderate (p<0.1) fluctuations. SIMPER analysis revealed shifts in macroinvertebrate assemblage along a hydrological gradient. CCA analysis revealed that an environmental gradient explained 88.8% of the variance in assemblage dynamics while Monte Carlo randomisation showed a significant relationship between assemblage dynamics and the environment. These results suggest that the seasonal flood pulse is a key driver of change in aquatic macro-invertebrate assemblages in the Delta. Water depth is the key driver of change in assemblage Stability (CV). Dynamic changes within the assemblage are driven primarily by Coleoptera and Corixidae populations

Owen George (Primary Presenter/Author)
Texas Tech University, owen.george78@gmail.com;

Scott Collins (Co-Presenter/Co-Author)
Texas Tech University, Scott.Collins@ttu.edu;

Abstract: Brown trout (Salmo trutta) are non-native to the Middle Rio Grande basin, New Mexico. Presently, these invaders overlap with multiple native fishes of conservation concern including Rio Grande sucker (Catostomus plebeius) and Rio Grande chub (Gila pandora). Despite concerns about the negative effects of these non-native salmonids, there remains limited data describing how Brown trout affect these native fishes. Specifically, Brown trout may compete for food resources with native fishes, thereby reducing growth and secondary production. We conducted a 3-month field study to assess the daily growth rates and secondary production of fishes in six streams within the Jemez River watershed. We found the daily growth rates of each species were inversely related to total fish density, indicating patterns of density-dependent growth. In streams with high Brown trout production, we observed lower production in Rio Grande sucker and Rio Grande chub in mainstem and tributary sites. One tributary went intermittent, resulting in negative growth and production in all species. Findings indicate that Brown trout are reducing secondary production of native fish populations.

Thethela Bokhutlo (Primary Presenter/Author)
Botswana International University of Science and Technology, thethela.bokhutlo@gmail.com;

Ketlhatlogile MOSEPELE (Co-Presenter/Co-Author)
Botswana University of Agriculture and Natural Resources, kmosepele@buan.ac.bw;

Belda MOSEPELE (Co-Presenter/Co-Author)
Botswana University of Agriculture and Natural Resources, bmosepele@buan.ac.bw;

Abstract: Environmental filtering and biotic interactions influence life histories of organisms in seasonally flooded river systems. However, little is understood about factors that affect the early life history of fish in heterogenous, river-floodplain systems of sub-Saharan Africa. Here, we assessed variability in growth rates of Juvenile cichlids (Coptodon rendalli and Tilapia sparrmanii) among regions of the Okavango Delta, Botswana. We sampled fish from three sites along a fluvial gradient from the upper to the lower Okavango Delta using a beach seine net. We determined age using micro-increment analysis from otoliths following standard procedure. We estimated growth rates using the Gompertz Growth Model. Analysis of variance showed significant differences in environmental parameters amongst sites. Similarly, growth rates differed among regions with juvenile fish from the upper Delta showing faster growth compared to those from the lower Delta. Predation and environmental factors were the major drivers of variability in fish growth suggesting that environmental variation influences resources and predator traits which may differ among habitats. Our results are consistent with the idea that biotic and abiotic factors may act in concert to regulate fish populations in seasonally flooded wetland systems.

Kurt Chowanski (Primary Presenter/Author)
South Dakota School of Mines, kurt.chowanski@sdsmt.edu;

Lisa Kunza (Co-Presenter/Co-Author)
South Dakota School of Mines and Technology, lisa.kunza@sdsmt.edu;

Michaela Halvorson (Co-Presenter/Co-Author)
South Dakota School of Mines, michaela.halvorson@mines.sdsmt.edu;

Abstract: Climate change and ubiquitous anthropogenic modification and management of river systems has degraded the quality of fisheries of interest to conservation and recreation. To understand population dynamics and address an apparent decline in sport fish in the Black Hills of South Dakota, we evaluated 30 years of fish monitoring data, and 1 year of daily ecosystem metabolism data. We linked monitoring data to management strategies, habitat restoration and improvement projects, and natural variability of environmental conditions. Abundance of trout decreased at lower stream flows and higher water temperatures. Lower trophic levels contributed less to the food web with decreasing light availability as moderated by topography and tree cover. In the Black Hills, elevated water temperatures and lack of thermal refuge, particularly during periods of low flow, contribute to population declines of trout.

Daniel Allen (Co-Presenter/Co-Author)
The Pennsylvania State University, dca5269@psu.edu;

Katharine Marske (Co-Presenter/Co-Author)
University of Oklahoma, kamarske@ou.edu;

Lucie Kuczynski (Co-Presenter/Co-Author)
University of Oldenberg, lucie.kuczynski@hotmail.com;

Michelle Busch (Primary Presenter/Author)
University of Kansas, m.h.busch@ku.edu;

Abstract: Understanding how communities assemble is a fundamental ecological question. Environmental filtering, where species occurrence is determined by abiotic habitat conditions, and limiting similarity, where species occurrence is determined by biotic interactions, have been identified as the main ways in which communities are assembled. To better understand how community assembly is impacted by global climate change, it is important to assess these processes through time. We investigate changes in assembly mechanisms of fish communities across Oklahoma, which has a striking precipitation gradient, using repeated fish surveys from 1969 to 2014. We compared temporal trends in taxonomic, functional, and phylogenetic diversity. Our results showed that limiting similarity was more important for assemblages with low historical richness, while environmental filtering was more important for sites with high historical richness. In addition, we found that while functional richness showed a shift from limiting similarity to environmental filtering, phylogenetic diversity showed the opposite. This suggests complementary dynamics between phylogenetic and functional richness. Our findings demonstrated the importance of examining assembly rules through time to better understand long-term community dynamics under global change.

Seoghyun Kim (Primary Presenter/Author)
Department of Biology, University of North Carolina at Greensboro, s_kim53@uncg.edu;

Christy Dolph (Co-Presenter/Co-Author)
Department of Ecology, Evolution and Behavior, University of Minnesota, dolph008@umn.edu;

Akira Terui (Co-Presenter/Co-Author)
Department of Biology, University of North Carolina at Greensboro, hanabi0111@gmail.com;

Abstract: Understanding factors affecting species distribution is a key topic in freshwater ecology. While most studies of freshwater fishes have focused on the effects of environmental drivers and negative interactions on species distribution, positive interactions (e.g., mutualism) are now recognized as an important determinant of species distribution. However, much less is known about the role of positive interactions in driving large-scale distribution patterns, such as metapopulation occupancy. Here, we focus on reproductive mutualisms between nest-building (host) and nest associates (beneficiary species) to quantify the effect of positive biotic interactions on metapopulations of stream fishes in the Midwest USA. We used a regional fish database and developed a conceptual hypothetical pathway depicting interrelationships between abiotic variables and biotic interactions to quantify watershed-scale occupancies of study species and their associations with environments. Piecewise structural equation modeling highlighted that host species greatly increased the metapopulation occupancy of nest associates, while influences of abiotic predictors on the occurrence varied by species. Our results provide quantitative evidence that positive interactions drive large-scale distributions of stream fishes that may provide valuable insights into conservation and management actions.

Rodney Rountree (Co-Presenter/Co-Author)
University of Victoria, rrountree@fishecology.org;

Francis Juanes (Co-Presenter/Co-Author)
University of Victoria, juanes@uvic.ca;

Kelsie Murchy (Primary Presenter/Author)
University of Victoria, kmurchy@uvic.ca;

Abstract: Stream salmonids inhabit areas impacted by aerial, terrestrial and underwater conditions, including sounds produced in each habitat. Similarly, sounds produced in each realm, from predators (e.g. bears walking) and prey (e.g. insects flying), likely influence the behavior of salmonids. The role of the holo-soundscape in the behavioral ecology of salmonids in these habitats has not previously been considered. Research on freshwater soundscapes was reviewed and synthesized to present an overview of the potential importance of the holo-soundscape to stream-dwelling salmonids. Freshwater soundscapes show consistent trends in ambient noise based on habitat type, bathymetry, and flow rates. In nosier habitats, sound levels decrease at low frequencies, creating a ‘window’ for biological noise. This window overlaps with the peak sensitivity in salmonids and literature on sound production in salmonids demonstrates some sounds fall within this window but there are also sounds that are above the known hearing range. Anthropogenic noise also continues to be a hazard for salmonids in streams, with boat and aerial sounds (e.g. traffic) that overlap with biological sounds. Freshwater soundscapes are just beginning to be understood but are a key component for understanding the behavior of salmonids.

Peter McIntyre (Co-Presenter/Co-Author)
Cornell University, pbm3@cornell.edu;

Montana Airey (Primary Presenter/Author)
Cornell University, ma2276@cornell.edu;

Abstract: Small fish are often pooled together despite being both trophically and taxonomically diverse. In the thousands of lakes within New York’s Adirondack Park, minnows are the most diverse family of fish, but their functional roles are poorly understood. This study uses stable isotope analysis (d13C and d15N) to profile the trophic ecology of fish communities from 5 waters along gradients of native mesopredator species richness and introduced species richness. Comparing community and species level metrics, we analyze differences in community structure and the roles of individual species between lakes. We document small-bodied fishes acting as top-predators in waters without salmonids or bass. In all waters, minnows exhibit unique functional roles and differentiate along isotopic resource axes. Furthermore, minnows interact with their community from various trophic positions and can function as top-predators, higher-level mesopredators, and lower-level omnivores. Warming and invasive species can alter fish community assembly and relative abundances. Documenting the functional roles of these species creates an important baseline and can help forecast changes in prey suppression, species interactions, or nutrient cycling that may occur with these shifting community dynamics.

Eric Billman (Co-Presenter/Co-Author)
Brigham Young University - Idaho, billmane@byui.edu;

Jon Flinders (Co-Presenter/Co-Author)
Idaho Department of Fish and Game, oclarkiiutah@gmail.com;

Darby Byington (Primary Presenter/Author)
Indiana University of Pennsylvania, msncc@iup.edu;

Abstract: Shorthead sculpin (Cottus confusus) in Birch Creek, Idaho, were found infected with the trematode Euryhelmis cotti. Our objective was to evaluate if infection intensity influenced growth, reproduction, and mortality of sculpin at two sites in Birch Creek. Prevalence of trematode infection was 100% upstream compared to 32% downstream; intensity of infection was at least 15 times greater in sculpin upstream. von Bertalanffy growth models differed between sites; growth coefficient (K) was higher for sculpin at the upstream site. Gonadosomatic index for both males and females was higher for sculpin found upstream. Females upstream had more eggs/clutch compared to downstream. Annual mortality was higher upstream (A=57%; 95%CI: 52–62%) compared to downstream (A=42%; 95%CI: 38–46%). Consequently, the density of sculpin was lower upstream (13 fish/100 m2) compared to downstream (54 fish/100 m2). We found no evidence to suggest growth and reproduction of sculpin were influenced by infection of E. cotti, but rather were influenced primarily by density-dependent factors. Mortality was higher for sculpin upstream with high prevalence and intensity of infection. However, we do not know if higher mortality was a direct consequence of trematode infection or merely correlated with trematode infection.

Sven Norman (Primary Presenter/Author)
Umeå university, Department of Ecology and Environmental Science, sven.norman@umu.se;

Abstract: Most fish species undergo ontogenetic niche shifts feeding on small sized prey like pelagic zooplankton as young while they with increasing size shift to larger prey such as benthic invertebrates. Theory suggest that, besides the total productivity of an ecosystem, the relative resource production between the pelagic and benthic habitats may have major effects on the production and population biomass of fish. We studied lake populations of Arctic char and brown trout in oligotrophic lakes in northern Sweden and find support for that increasing proportion of benthic production, which provides resources mainly for adult fish, results in higher population biomass and larger maximum and mean sizes of fish – regardless of the total productivity of the benthic habitat alone or the ecosystem as a whole. We link our results to theory on the effects of ontogenetic asymmetry in energetic efficiency between juvenile and adult fish.

Susanna Harrison (Primary Presenter/Author)
The Ohio State University, harrison.852@buckeyemail.osu.edu;

Abstract: Artificial light at night (ALAN) is one of the most pervasive sources of anthropogenic pollution and threatens ecological communities and global biodiversity. However, research on the impacts of ALAN often focuses on individual taxa without exploring how light pollution might influence community-to-ecosystem dynamics. Our research examines differences in fish community composition along nighttime light-intensity gradients created by roadway lighting on bridges over river-reservoir systems. We performed electrofishing surveys of the fish community along light-to-dark transects extending from six bridges (four with lighting, two without). Over the two-month study period, we captured 4,106 fish representing 38 different species. The most abundant species were Gizzard Shad (Dorosoma cepedianum, n = 2,422) and Bluegill (Lepomis macrochirus; n = 776). We did not capture more than 200 individuals of any other species. We are applying several measures of diversity to assess differences in community composition between lit and unlit bridges and areas of high and low light infiltration. We expect many fishes to face a trade-off between risking increased exposure to predation and exploiting increased foraging opportunities under ALAN.

Seiji Miyazono (Primary Presenter/Author)
Yamaguchi University, seiji.miyazono@gmail.com;

Takao Kodama (Co-Presenter/Co-Author)
Yamaguchi University, a005veu@yamaguchi-u.ac.jp;

Yoshihisa Akamatsu (Co-Presenter/Co-Author)
Yamaguchi University, yakamats@yamaguchi-u.ac.jp;

Ryohei Nakao (Co-Presenter/Co-Author)
Yamaguchi University, lineck92@yahoo.co.jp;

Satsuki Tsuji (Co-Presenter/Co-Author)
Yamaguchi University, satsuki.may425@gmail.com;

Abstract: River tributaries have a variety of important ecological functions for fishes in a river network. Understanding spatiotemporal fish assemblage patterns in natural and artificial tributary habitats is important for estimating the effects of river modification on fishes and developing the conservation strategies. In this study, we examined the fish assemblage patterns on different tributary habitat types (natural tributary stream vs. irrigation channel) and seasons (fall vs. winter) in the Gonokawa River in Japan using quantitative environmental DNA (eDNA) metabarcoding. The analysis results indicate that the species richness in the natural tributary streams was higher than that in the irrigation channels. In addition, the eDNA concentrations of fishes that tend to prefer sand/gravel substrates or aquatic vegetation in the natural tributary streams were higher than those in the irrigation channels. From September to November, the eDNA concentrations of the fish species (Zacco platypus) has significantly increased in the natural tributary streams. These results suggest that (1) artificial stream modifications (e.g., river revetment) would affect fish species richness in the tributaries, and (2) certain fish may have seasonally used the natural tributary stream as their temporal habitats (e.g., overwintering habitats).

Malia Armstrong (Primary Presenter/Author)
Middlebury College, mearmstrong@middlebury.edu;

Abstract: Our investigation sought to determine whether embryonic Atlantic salmon have the ability to imprint upon odors in order to locate natal streams later in life, as well as whether rearing and imprinting fish in different water sources has an impact on that ability. Using behavioral and physiological experiments, we demonstrated that adult Atlantic salmon show a preference for the water to which they were imprinted upon in early life stages. Additionally, we found different water sources impacted the efficacy of this imprinting. These results, indicating that water source during development may affect the ability to imprint, have implications for hatchery programs that often incubate salmonids in well water during the alevin life stage. This study provides a novel example of not only the ability for Atlantic salmon to imprint at embryonic life stages but also how that ability may be affected by environmental factors.

Lauren Stoczynski (Primary Presenter/Author)
Clemson University, lstoczy@clemson.edu;

Brandon Peoples (Co-Presenter/Co-Author)
Clemson University, Peoples@g.clemson.edu;

Luke Bower (Co-Presenter/Co-Author)
Clemson University, lmbower@clemson.edu;

Abstract: Humans have an ever-growing impact on our freshwater systems. While previous research has focused on environmental filtering and species sorting in structuring stream fish communities, less research has focused on understanding how environmental filters disentangle into natural or anthropogenic origins. Including phylogenetic and trait measures of community assembly, with taxonomic measures, could further explain variation structuring fish communities. We acquired a large-scale data set including 350 sites from South Carolina Department of Natural Resources and collected natural environmental data from the sites along with detailed trait data and a phylogenetic tree with all species. We gathered anthropogenic data using StreamCAT database. We used variation partitioning to determine the percent of explained variation of taxonomic, functional, and phylogenetic beta diversity from natural, anthropogenic, and space on all of South Carolina and four major watersheds. We hypothesized that functional and phylogenetic beta diversity will show more explained variation than taxonomic beta diversity. We additionally hypothesize that anthropogenic variation will explain more variation than natural variation the four main watersheds compared to the whole state. This study could provide a new way to understand how human may be impacting stream fish communities.

Karen Baumann (Co-Presenter/Co-Author)
Murray State University, kbaumann1@murraystate.edu;

Kinga Stryszowska-Hill (Co-Presenter/Co-Author)
Murray State University, kstryszowskahill@murraystate.edu;

Michael Flinn (Co-Presenter/Co-Author)
Murray State University, mflinn@murraystate.edu;

Luke Zuklic (Primary Presenter/Author)
Murray State University, lzuklic@murraystate.edu;

Abstract: Private-public partnership programs, like the Wetlands Reserve Program (WRP), are designed to restore critical ecological function and wildlife habitat in wetlands, however, these projects are rarely monitored long-term. The objective of our study was to quantify and compare fish communities in wetlands across a gradient of disturbance: cultivated, restored, reference, to examine the success of wetland restoration. From spring 2019 to summer 2020, we performed monthly electrofishing surveys of fish communities in wetlands (n=12) throughout western Kentucky, USA. 11,687 individual fish were collected across 58 species. Species richness and non-metric multidimensional scaling were used to quantify fish communities present and determine differences between wetland types. Restored and reference wetlands had significantly greater richness than cultivated wetlands, however, fish abundance in all wetlands was not significantly different. Our findings suggest that fish communities in WRP and reference wetlands are more diverse than cultivated wetlands, several taxa are more likely to dominate communities in cultivated wetlands, and fish communities in most wetlands responded positively to longer hydroperiod and warmer minimum temperatures. This research suggests that current WRP hydrologic restoration should continue to be implemented to improve diversity in fish communities.

Angélica M. Torres Bejarano (Primary Presenter/Author)
Universidad Nacional de Colombia, angmtorresbej@unal.edu.co;

Carlos Cáceres (Co-Presenter/Co-Author)
The Ohio State University, carlos.l.caceres@gmail.com;

Gabriel J. Colorado Z. (Co-Presenter/Co-Author)
Universidad Nacional de Colombia, gjcoloradoz@unal.edu.co;

S. Mažeika Patricio Sullivan (Co-Presenter/Co-Author)
The Ohio State University, mazeika3@gmail.com ;

Abstract: The Amazon rainforest has experienced extensive deforestation of riparian areas, putting at risk one of the most diverse freshwater fish assemblages on the planet. At nine study reaches distributed among three Colombian blackwater streams, we assessed how variability in riparian vegetation structure (i.e., canopy cover) influenced the taxonomic and functional diversity of fish assemblages during both dry and rainy seasons. We did not observe differences in taxonomic measures associated to changes in riparian canopy cover, including species richness and evenness. However, we observed that only 16% of species were observed in both rainy and dry seasons and that evenness was 8% greater in the dry season. Diet varied by riparian vegetation: 56% of fish stomach contents were of allochthonous origin in stream reaches with forest vegetation compared to 37% in streams with altered riparian vegetation. Both functional divergence and dispersion – measures of the variability of species’ traits – were higher in reaches with more intact vegetation during the rainy season. Our findings highlight the importance of the interaction of riparian vegetation and seasonality, and both longitudinal and lateral hydrological connectivity, for fish functional diversity of Amazonian streams.

David J. Janetski (Primary Presenter/Author)
Indiana University of Pennsylvania, janetski@iup.edu;

Bo Putt (Co-Presenter/Co-Author)
Indiana University of Pennsylvania, puttbo@gmail.com;

Jeffery Larkin (Co-Presenter/Co-Author)
Indiana University of Pennsylvania , nzqw@iup.edu;

Ed Patterson (Co-Presenter/Co-Author)
Indiana County Parks and Trails, indparks@gmail.com;

Josiah Townsend (Co-Presenter/Co-Author)
Indiana University of Pennsylvania, josiahtownsend@gmail.com;

Abstract: Each spring many salamanders are killed on roadways as they cross in mass to floodplain and vernal pools for breeding, yet mortality rates are rarely quantified. To address this research need, we measured road mortality of spotted (Ambystoma maculatum) and four-toed salamanders (Hemidactylium scutatum) during their annual spring breeding migration to a large floodplain pool in western Pennsylvania. We estimated mortality as the proportion of observed salamanders on the road that had been killed by vehicles. Salamanders migrated exclusively on rainy nights in late March and early April when air temperatures were 8.9 to 13.3°C. We counted 231 individuals on the road representing 10 amphibian species, of which 126 were spotted and 30 were red-toed salamanders. Maximum road crossing rate was 44 salamanders/hr over the 300-m road section surveyed, and maximum mortality rate was 10 salamanders/hr. The two most frequently killed salamander species were spotted and four-toed salamanders, with mortality rates of 10.3% and 23.3%, respectively. Other species experiencing mortality were northern red and red-backed salamanders, as well as eastern newts and frogs (killed frogs were unidentifiable). Our study shows that roadways can cause substantial mortality in amphibian populations.