Fisheries management has historically focused conservation efforts on game or sport species. However, most species are nongame-those not traditionally captured for sport or harvest in countries where recreational fisheries predominate. Greater conservation of nongame species could help ensure that population declines do not go unnoticed. Unfortunately, fisheries managers already manage complex ecosystems with limited resources, and they frequently are directed to focus on game fishes. However, game fish populations can also be tightly coupled to nongame fishes, so nongame management can sometimes also benefit game species. We reviewed functional roles of freshwater nongame fishes and suggest categories that may be especially important for conservation. Of note, nongame fishes are more imperiled than game fishes and fill largely distinct functional roles. These roles include food-web impacts, ecosystem engineering, and mussel hosting. Management priorities could include nongame piscivores and species with high biomass, especially herbivores, nest builders, and imperiled mussel hosts. We provide practical options for including nongame fishes in current management, many of which require little additional funding. These include recognizing when sport fish funding and conservation can also benefit nongame species, whole-community sampling at some monitoring locations, collecting catch data for select species observed during game fish surveys, embracing environmental DNA sampling, and making presence-absence record keeping the default option.

ABSTRACT The carpsuckers (Carpiodes spp.) are a little‐studied genus of three medium‐sized (0.5–3 kg at maturity) freshwater fishes within Catostomidae. These three species are widespread and common in some larger rivers in central North America, as well as some larger lakes and reservoirs. The lapillus otoliths of 189 carpsuckers (117 quillbacks [Carpiodes cyprinus], 44 highfin carpsuckers [Carpiodes velifer], 23 river carpsuckers [Carpiodes carpio] and 5 intergrades) were aged, all collected from the same Lower Wisconsin River community in 2023 and 2024 during Wisconsin Department of Natural Resources fish surveys. Age scores were precise among readers (mean coefficient of variation = 4.7%). Growth in size of each species was best modelled by von Bertalanffy growth functions accounting for sexual dimorphism, and the first comparative assessment of all three species’ growth profiles was provided. These results showed that each species exhibited highly variable recruitment across time, with most individuals from year classes produced in 2005 or earlier. Maximum ages greater than 50 years for each of the three species were observed: highfin carpsucker (56 years), quillback (51 years) and river carpsucker (56 years), as well as a maximum age of 44 years among the small sample of intergrades, making Carpiodes the second genus of freshwater fish for which three or more species have been shown to live more than 50 years. A maximum age of 56 years for the highfin carpsucker is more than six times greater than previously reported and, based on available knowledge, represents the longest lived, smallest bodied (L∞ < 40 cm total length [TL]) freshwater fish by more than 25 years. Carpsuckers are long‐lived periodic strategists living in increasingly human‐altered ecosystems, as is the case for many catostomids.

Objective: Declines in Cisco Coregonus artedi populations in some inland lakes have prompted assessments of Cisco occurrence and extirpation risk in relation to various stressors to identify refuge lakes and factors that promote Cisco persistence. However, most previous assessments have focused on presence-absence of Cisco rather than examining how population characteristics, such as relative abundance or growth, might change in relation to lake- and landscape-level environmental factors. Consequently, our specific objectives were to identify important environmental factors explaining variation in Cisco relative abundance and growth and to determine whether population metrics describing size and age distributions were related to relative abundance in Wisconsin inland lakes.Methods: Cisco were collected from 48 inland Wisconsin lakes during 2011-2015 using vertical monofilament gill nets and population-specific relative abundance estimates (catch per unit effort [CPUE]) were quantified as the number of individuals per gill-net night. Sagittal otoliths were removed from a subsample of Cisco for age estimation and growth was indexed as mean total length (TL; mm) at age 2. Length and age data were used to develop a suite of metrics describing size and age distributions of each population. Random forest models were used to evaluate relationships between 10 biologically relevant predictor variables representing variation in physical, climatic, catchment, and limnological characteristics and Cisco CPUE and growth. Pearson correlations were used to determine whether population characteristics were related to CPUE.Result: Cisco populations exhibited large variation in relative abundance, growth, and size and age distributions. Best-fit random forest models explained approximately 25% of the variation in Cisco CPUE and 46% of the variation in growth. Growing degree-days and variables associated with availability, quality, and quantity of suitable oxythermal conditions were identified as important predictors of both Cisco CPUE and growth; CPUE was also identified as an important predictor of growth. Mean TL and mean TL at age 2 were negatively related to Cisco CPUE, whereas mean age, number of age-classes present, and maximum observed age were positively related to CPUE.Conclusion: Our results suggest that maintenance of suitable oxythermal habitat conditions may be critical to conserving abundant Cisco populations. Our assessment also provides insights on how Cisco populations may respond to environmental and anthropogenic stressors, which could aid ongoing and future conservation and management efforts in Wisconsin and elsewhere.

Hybridization among gar species (Pisces: Family Lepisosteidae) has only recently been documented, and relatively few occurrences have been reported. In the Fox River drainage of the Lake Michigan Basin in Wisconsin, apparent hybrids and introgressed individuals (hereafter "hybrids") of Longnose Gar (Lepisosteus osseus) and Shortnose Gar (L. platostomus) were widespread and numerous, constituting about 44% of the total gar population. Presumed hybrids could be readily distinguished by either their intermediate ratio of snout length to snout width or a low ratio, characteristic of Shortnose Gar, coupled with the presence of conspicuous spots on the top of the snout, an occasional Longnose Gar characteristic. Presumed hybrids had genetic matrilines (cytochrome b) of either Shortnose or Longnose Gar. Apparent hybrids occur commonly throughout the Fox River drainage, including the upper and lower Fox River, its major tributary the Wolf River, the riverine lakes Poygan, Winneconne, Butte des Morts, Winnebago, and Little Butte des Morts, and Green Bay, Lake Michigan, near the mouth of the lower Fox River. Evidence exists for possible hybrids in the adjacent Mississippi River basin and the Missouri River basin, but they appear to be less common and more localized. Extensive hybridization and introgression in the Fox River drainage may have been facilitated by the close phylogenetic relationship of Longnose and Shortnose Gar, the much greater abundance of Longnose relative to Shortnose Gar in the Fox River drainage, the apparent relatively recent colonization of the Fox River drainage by the Shortnose Gar, and the substantial modification and loss of gar spawning habitat in the Fox River drainage caused by dams and artificial water level regulation.

Coregonus artedi (Cisco) and Coregonus clupeaformis (Lake Whitefish) are coldwater fishes native to some inland lakes in Wisconsin. We conducted a statewide assessment of Cisco and Lake Whitefish status using experimental-mesh vertical gillnets during the summers of 2011-2014. Cisco and Lake Whitefish relative abundances varied from 0 to 137 and 0 to 3 fish/net night, respectively. About 29% of the Cisco and 33% of the Lake Whitefish populations were potentially extirpated from inland lakes in Wisconsin; most potential extirpations were from southern Wisconsin, but extirpations occurred statewide. Invasive species, climate change, land-use change, and excess nutrient loading may have contributed to causing extirpations of Cisco and Lake Whitefish. Conservation of remaining populations of Cisco and Lake Whitefish will require efforts to minimize these perturbations.

This chapter examines potential metrics for their correlations with independent measures of the environmental quality of Wisconsin lakes and for their temporal and spatial variability when environmental quality is stable. Fish assemblages reflect the overall integrity of biological communities and are excellent indicators of the environmental quality of aquatic ecosystems. Several types of environmental indices based on fish assemblages have been developed, with the most widely used and most effective based on the Index of Biotic Integrity. The Sparkling Lake data were used to quantify within-year variation in metric values in the absence of significant changes in environmental quality. In Sparkling Lake, inclusion of young-of-year fish in calculations had different effects on species richness as estimated by seining. The proportion of individuals as intolerant species had a stronger correlation with Trophic State lndex (TSI) than the number of intolerant species for both methods; the index sample relation with TSI was stronger than the fyke sample's for this metric as well.

The genus Chapalichthys (Cyprinodontiformes: Goodeidae) consists of three allopatrically distributed species that occur on the Mesa Central, Mexico. Chapalichthys encaustus primarily occurs in the Río Lerma-Santiago basin, whereas both C. peraticus and C. pardalis have restricted distributions in the adjacent Río Balsas basin. Taxonomic issues in the genus center around the validity of C. peraticus. A formal systematic and taxonomic assessment of the genus inclusive of all three species of Chapalichthys has never been conducted. Therefore, the objectives of this study were two-fold: 1) to assess the phylogenetic relationships among multiple populations and all three species of Chapalichthys using 1,047 bp of mtDNA (ND2) sequence data, and 2) in light of the phylogenetic results, to re-examine the taxonomic status of C. peraticus using meristic and pigmentation characters. The phylogeny indicates two clades, each consisting of a valid species. One clade includes multiple populations of C. encaustus, and a second clade consists of multiple individuals of C. pardalis and C. peraticus. Chapalichthys pardalis and C. peraticus possess nearly identical mitochondrial sequences for ND2. Morphologically, meristic counts of all characters examined showed overlap for all three species and provide no species-specific diagnostic information. Chapalichthys encaustus can be differentiated from C. pardalis and C. peraticus based on the presence of vertical bars along the lateral flank versus a spotted pattern in the other two species. Chapalichthys pardalis and C. peraticus cannot be differentiated from one another based on pigmentation or meristics. The results from this study support the recognition of only two species of Chapalichthys: C. encaustus and C. pardalis.

Successful fisheries management practices developed for one ecosystem can often be used in similar ecosystems. We developed a flexible lake classification framework in collaboration with similar to 100 fisheries biologists for improved fisheries conservation management in Wisconsin, USA. In total, 5,950 lakes were classified into 15 lake classes using a two-tiered approach. In tier-one, lakes were clustered into "simple" and "complex" sportfish assemblages. In tier-two, lakes were further clustered using accumulated degree days, water clarity, and special cases. We focus on temperature and clarity because these factors often drive fisheries change over time-thus a lake's class can change over time. Lake class assignments were refined through a vetting process where fisheries biologists with expert knowledge provided feedback. Relative abundance, size-structure, and growth rates of fishes varied significantly across classes. Biologists are encouraged to utilize class interquartile ranges in fisheries metrics to make improved fisheries assessments. We highlight hard-won lessons from our effort including: (1) the importance of co-developing classification frameworks alongside fisheries biologists; and (2) encouraging frameworks where lakes can shift classes and fisheries expectations over time due to factors like climate change and eutrophication.