Illinois Indiana Sea Grant

• Traditional benthic grabs were combined with underwater video to detect hypoxic habitats. • Significant grouping in video data was supported by cluster analysis of environmental parameters. • There was a significant separation of benthic communities among the selected video groups. • Hypoxic habitats had reduced species diversity and a higher proportion of tubificids. • Video analysis can detect hypoxic habitats once a baseline is established. Ongoing anthropogenic eutrophication and warming temperatures are expected to increase the extent and severity of hypoxia globally. Monitoring hypoxia has traditionally relied on costly surveys or sensor networks. While benthic macroinvertebrates are valuable indicators of hypoxia, community analysis is limited by small spatial scales of traditional grab sampling and labor-intensive processing. To address this, we combined benthic grab samples with underwater video to detect hypoxic habitats in two productive embayments of the Laurentian Great Lakes: Saginaw Bay, Lake Huron with periodic short-term hypoxia, and Hamilton Harbour, Lake Ontario with prolonged hypoxia. Using supervised classification, we identified significant grouping of in situ video data with cluster analysis, and then aligned video groups with environmental and biological datasets. These video groups were supported by cluster analysis of measured environmental variables, with clusters differing in duration of low near-bottom dissolved oxygen concentration and by depth. Independent cluster analysis confirmed significant separation of benthic communities among the selected video groups, with hypoxic habitats showing reduced species diversity and a higher proportion of tubificids. The gradient of conditions sampled in our study revealed assemblages of benthic invertebrates sensitive to and tolerant of hypoxia. The agreement among video, biological, and environmental data confirmed that video analysis can provide a novel, quick and reliable method to detect benthic habitats affected by hypoxia and determine their spatial extent once a baseline is established.

Temperate fishes often spawn in response to environmental cues, such as temperature, thereby facilitating larval emergence concurrent with suitable biotic and abiotic conditions, such as plankton blooms. Climatic changes may alter the reproductive phenology of spring- and autumn-spawning freshwater fish populations. Such effects may depend on the sensitivity of reproductive phenology to ambient temperatures. We applied a meta-analysis approach to test whether annual temperature and year affected fish reproductive phenology. Based on preliminary tests in walleye (Sander vitreus) and Lake Constance whitefish (Coregonus arenicolus), we hypothesized that increasing temperature would promote earlier spring-spawning and later autumn-spawning. We found spawning was significantly earlier in the spring and later in the autumn. We found that migration of autumn-spawning species occurred earlier with warmer temperatures, implying that with increasing temperatures, migrating autumn-spawning species will increase residence time in tributaries. We also found that spring-spawning fishes reproduced earlier in more recent years, while we observed no significant effect in autumn-spawners. Spring- and autumn-spawning fishes displayed interannual variation in spawning dates (mean range of 34.4 and 27.0 days over 33.9 years, respectively), with spring-spawning fishes displaying a significantly broader range in spawning dates.

Fish recruitment is interannually variable and challenging to predict. Annual recruitment is often regionally synchronized among populations and identifying drivers of such synchrony may help shed light on recruitment dynamics. We investigated interannual variation of alewife Alosa pseudoharengus recruitment by estimating year-class strength for populations from three of the Laurentian Great Lakes (lakes Huron, Michigan, and Ontario) using annual assessment survey data from 1968 to 2022. We first determined the age when year-class strength was set for each dataset. We then used a mixed-modeling approach incorporating age, year-class, and sampling year to estimate year-class strength for each study lake. Thereafter, we evaluated regional synchrony in year-class strength across the three lakes and evaluated potential climatic drivers of synchrony. Our results suggest that alewife year-class strength is set by age-1. Our model-derived indices of alewife year-class strength were synchronized among the three lakes, and we identified spring-summer degree-days as a potential regional driver of synchrony. This analysis highlights the potential for strong influence of climatic conditions on fish recruitment in large freshwater systems.

Abstract Juvenile stages of fishes are frequently bottlenecks to recruitment. Habitat use of early life stages and the extent to which fish rely on local resources may affect how they respond to habitat loss and alterations, with important implications for habitat management. To investigate the potential for prolonged reliance on local resources, we quantified stable isotope ratios (δ13 carbon, δ15 nitrogen, δ18 oxygen and δ2 hydrogen) of young‐of‐year (YOY) largemouth bass Micropterus salmoides and isotope ratios of locally collected water and potential prey across three study components, a controlled pond experiment, a multi‐lake survey and a detailed single‐lake survey. Across study components, we observed habitat and site fidelity of YOY largemouth bass in mid‐summer, demonstrated by distinct spatial differences in young bass stable isotope ratios. Additionally, we observed significant, positive correlations between δ13C of YOY largemouth bass and δ13C of locally collected invertebrates and small bluegill Lepomis macrochirus in the single lake survey, suggesting localised foraging. Later in summer, spatial differences in largemouth bass stable isotope ratios were not apparent, indicating a transition to more spatially integrated foraging. Prior to switch to piscivory, YOY largemouth bass rely on local resources indicating that they may be more susceptible, both positively and negatively, to hyper‐local changes in forage availability or disturbances. This study demonstrates that stable isotope ratios allow for differentiating environmental experiences among young fish in relatively close proximity in small freshwater systems. Moreover, high spatial variation of consumer stable isotope ratios demonstrates the importance of considering spatial heterogeneity in stable isotope studies.

Abstract Ecological studies have traditionally treated fish species or populations as homogenous groups; however, numerous studies have shown that intrapopulation variation in resource use is widespread. Within‐species diet differences are evident in small and large freshwater systems and may influence trophic and population dynamics. In a previous study of young yellow perch, spatial intrapopulation diet variation was observed for stomach contents, a relatively short‐term diet indicator. In the current study, we build upon the earlier study of yellow perch in Saginaw Bay, Lake Huron, and assess patterns of long‐term diet indicators (stable isotopes and morphology) to assess consistency of diet variation over time and improve characterisation of trophic differences among sites. Specifically, we analysed soft tissue samples for carbon (δ13C) and nitrogen (δ15N) isotope ratios and used geometric morphometrics to describe morphological variation of young yellow perch. While both isotopes displayed significant spatial differences, δ15N values demonstrated a much clearer separation among sites, with greater δ15N values for yellow perch collected closer to the mouth of the Saginaw River. Morphological variation also was more apparent among sites rather than between years or months, with more streamlined yellow perch morphologies evident at sites where they consumed high proportions of zooplankton relative to benthic invertebrates. Somewhat unexpectedly, soft tissue δ13C values varied strongly between the two study years; however, the ultimate cause of such interannual variation in δ13C is unclear. These long‐term indicators showed consistent spatial differences, which suggests that individual fish are using resources at a particular site long enough to reflect a stable isotope or morphological signal. Yellow perch production at different locations seemingly relies on different prey resources, suggesting that annual variation in dominant trophic pathways may alter the performance of yellow perch at each location.

While the U.S. makes up around 5% of the world’s population, we consume approximately 75% of the world’s prescription drugs—well over 4 billion prescriptions per year. Approximately one third of those are never used, creating an array of public health challenges. These challenges include land and water pollution; unintentional inappropriate use and unintentional human, pet, and wildlife poisonings; and intentional drug abuse and diversion. Misuse of prescription drugs now exceeds that of all illegal drugs combined. Reducing the number of medications prescribed is of primary importance, as well as collecting unnecessary medications from households and disposing of them through environmentally friendly methods. There are a variety of medication collection methods, including public take-back events, permanent drop boxes at pharmacies, collection by police departments, as well as prepaid mailers available from some pharmacies and the Internet. When bulk medication is collected at take-back events or by police departments, it is generally quantified as “pounds collected,” with no determination of specific medications collected, quantities of prescribed medications left unused, or length of household storage beyond the expiration date. Pharmacy students are uniquely positioned to explore these unknowns and develop solutions with their high level of drug expertise. This research study combined with community service events involved the collaboration of pharmacy students with environmentalists, community volunteers, and law enforcement officers to collect and analyze unwanted medications, as well as explore factors pertinent to this public hazard.

Hyperlocal relationships are internet-enabled interactions in a common locale. They are opening new frontiers for geographically based, community-oriented, and civically engaged action. However, the influences of virtual interactions over procedural aspects of sustainability projects are not fully theorized. To fill this gap, we examine whether anticipating the use of social media re-shapes how the community voice method (CVM) intervenes in deliberative spaces associated with waterway sustainability in Milwaukee, Wisconsin (USA). CVM is a video-based participatory research approach designed to foster inclusive and community-focused planning. Like most visual methods, it originated before the wide availability of interactive web 2.0 technologies. Our working hypothesis is that the intention to engage the public through online fora creates a new group of stakeholders who are poorly understood. As a result of analyzing field notes, audio-visual recordings of participants, and other documents, we find that anticipating the use of social media shapes all aspects of participation, including: awareness of context, group dynamics, interventions, outcomes of concern. Concern for the opinions and perspectives of hyperlocal participants re-shapes recommendations about how to align research projects with community needs and planning deliberation. Social media is an important outlet for the work, but changed the placement of video products in relation to waterway sustainability plans, especially with respect to environmental justice. We conclude by proposing a framework for hyperlocal sustainability research that appropriately emphasizes justice.