Understanding the age structure and population dynamics of harvested species is crucial for sustainability, especially in fisheries. The Bigmouth Buffalo ( Ictiobus cyprinellus ) is a fish endemic to the Mississippi and Hudson Bay drainages. A valued food-fish for centuries, they are now a prized sportfish as night bowfishing has become a million-dollar industry in the past decade. All harvest is virtually unregulated and unstudied, and Bigmouth Buffalo are declining while little is known about their biology. Using thin-sectioned otoliths and bomb-radiocarbon dating, we find Bigmouth Buffalo can reach 112 years of age, more than quadrupling previous longevity estimates, making this the oldest known freshwater teleost (~12,000 species). We document numerous populations that are comprised largely (85–90%) of individuals over 80 years old, suggesting long-term recruitment failure since dam construction in the 1930s. Our findings indicate Bigmouth Buffalo require urgent attention, while other understudied fishes may be threatened by similar ecological neglect.

Despite decades of commercial harvest of bigmouth buffalo (Ictiobus cyprinellus) from Jamestown Reservoir, North Dakota, and the recent rapid growth of sport bowfishing that targets this species, there is a lack of biological information on this native catostomid. At present, no-limit recreational and commercial harvest of bigmouth buffalo occurs in North Dakota, with no harvest-reporting for recreational take. A long-lived life history was recently documented for this species with a lifespan exceeding 100 years. At Jamestown Reservoir, bigmouth buffalo were aged to 58 years of age, with onset of sexual maturity 10 years for females. Evidence for episodic recruitment over a 60-year period was in 1962–1979, 1993–2011, and 2017 with recruitment success more likely during non-drought periods. Annual commercial harvest data from this reservoir indicate bigmouth buffalo have declined significantly over the past 30 years, most precipitously since 2010 during the bowfishing era. The demographic patterns, episodic recruitment and harvest changes observed in this population are relevant for informing management of bigmouth buffalo and other long-lived freshwater fishes.

The Sport Fish Restoration Program (SFR) has been a stable and highly successful funding program supporting state fisheries research, propagation, and management activities since its inception in 1950. The expanding sport of bowfishing in the past 2 decades, and research over a comparable time period showing very long lifespans of underappreciated native fish species, opens the door to some new ways to classify, manage, and fund monitoring of these natives under the SFR program, while encouraging sport and commercial take of invasives. Evidence from bowfishing and from changes in angling patterns for some nongame species indicates that the time has come to consider reclassifying underappreciated native species into some form of sport status (entirely separate from non‐native invasives) and thereby potentially expanding the scope of species projects financed with SFR funds. Reclassification will also function to upgrade the status of underappreciated native species taken within agencies, with bowfishers and anglers, and with the public. It then opens the door to improved, and necessary, monitoring of inland commercial fisheries (often targeting the same species), an activity which has needed improvement and a reliable funding source for decades. We suggest that our approach is a comparatively straightforward one that is scientifically defensible and implementable within the existing state–federal management jurisdictions and institutions.

The Blue Sucker Cycleptus elongatus is an imperiled North American catostomid in need of management and protection. No hard structures are validated for aging this species, but past studies focused on somatic structures such as fin rays and scales. Calculated parameters (mortality, recruitment, growth) that inform management decisions are directly influenced by the accuracy and precision of the hard structure used to estimate age. We identify the most precise and credible structure with which to age Blue Suckers while also completing the first in-depth investigation of their otoliths. We collected Blue Suckers (n = 168) from the lower Wabash River and compared ages estimated from scales, opercles, pectoral fin rays, and lapillus otoliths but were unsuccessful in estimating ages from cleithra. We identified structure bias between all structures and found scales (n = 67; maximum = 11 years, mean = 8.2 years) and opercles (n = 65; maximum = 15 years, mean = 8.3 years) to be substantially less precise than pectoral fin rays and lapillus otoliths. We found that otoliths (n = 128; maximum = 42 years, mean = 13.5 years) were more precise than fin rays (n = 167; maximum = 20 years, mean = 9.6 years) and yielded a much higher range of ages. We could not identify any range of ages or total lengths in which (nonlethal) fin ray age could be accurately corrected to (lethal) otolith age. Thin-sectioned otoliths are the gold standard for aging most fishes, including numerous age-validated catostomids, and the credibility of Blue Sucker otolith age estimates was additionally supported by a strong correlation between whole lapillus mass and estimated age (R 2 = 0.89). Overall, evidence indicates that Blue Sucker lapillus otoliths yield more precise and credible age estimates than other hard structures.

Although the pace of senescence varies considerably, the physiological systems that contribute to different patterns of senescence are not well understood, especially in long-lived vertebrates. Long-lived bony fish (i.e., Class Osteichthyes) are a particularly useful model for studies of senescence because they can readily be aged and exhibit some of the longest lifespans among vertebrates. In this study we examined the potential relationship between age and multiple physiological systems including: stress levels, immune function, and telomere length in individuals ranging in age from 2 to 99 years old in bigmouth buffalo (Ictiobus cyprinellus), the oldest known freshwater teleost fish. Contrary to expectation, we did not find any evidence for age-related declines in these physiological systems. Instead, older fish appeared to be less stressed and had greater immunity than younger fish, suggesting age-related improvements rather than declines in these systems. There was no significant effect of age on telomeres, but individuals that may be more stressed had shorter telomeres. Taken together, these findings suggest that bigmouth buffalo exhibit negligible senescence in multiple physiological systems despite living for nearly a century.

The bigmouth buffalo (Ictiobus cyprinellus) is an iconic freshwater fish native to North America that is in decline. Recent studies have revealed bigmouth buffalo exhibit a slow pace of life, yet demographic information on bigmouth buffalo outside of North Dakota and Minnesota is lacking. We used otoliths to investigate population demographics of bigmouth buffalo in Canada, and also monitored bigmouth buffalo spawning frequency and reproductive success in the wild. From a sample of 52 fish collected during 2018 – 2021 we found bigmouth buffalo from the Qu’Appelle system more than 125 years old. Only 13 year classes ranging from 1894 – 1997 were evident with only one year class since 1948, indicating recruitment has been episodic. During the past decade (2013 – 2022) bigmouth buffalo have spawned only once (May of 2013) in Buffalo Pound Lake. This spawning effort culminated in recruitment failure because the water-level recession rate was too rapid. Our findings indicate that bigmouth buffalo spawning attempts as well as recruitment occur within a narrow range of water-level fluctuations that may rarely occur, which is enabled by their supercentenarian lifespan, and has direct implications for the conservation of this species.

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Except for one unconfirmed case, chironomid larvae have been reported to pass through four larval instars between egg and pupal stages. We have observed a fifth larval instar to be a standard life-cycle feature of the podonomine Trichotanypus alaskensis Brundin 1966 in tundra ponds on the Arctic Coastal Plain near Barrow, Alaska. T. alaskensis has a one-year life cycle in these arctic ponds. Adults emerge in June ~2-3 weeks after pond thaw, then mate and oviposit; most newly-hatched larvae reach instar IV by October when pond sediments freeze. Overwintering larvae complete instar IV within a few days of thaw, then molt again to a fifth larval instar. Imaginal discs, normally seen only during instar IV in Chironomidae, develop across both instars IV & V prior to pupation and adult emergence. While monitoring larval development post-thaw in 2014, we noticed freshly-molted T. alaskensis larval exuviae a week or more prior to any pupation by that species. In 2015-16 we reared overwintering instar IV larvae from single pond sources, individually with daily monitoring, through molts to instar V, pupa, and adult. Some overwintering instar II and III larvae were reared as well, but were few in number. During 2016 we also reared T. alaskensis progeny (from eggs) through instar II, thus documenting head capsule size ranges for all five instars in a single pond’s population. Without individual rearings, the fifth larval instar was not readily apparent for two reasons: 1) The molt itself occurs immediately after thaw and is so synchronous it is difficult to discern in daily field samples. 2) The head capsule size increment between instars IV-V is much lower than the ratio predicted by the Brooks-Dyar Rule. Up through instar IV, the Brooks-Dyar ratio for T. alaskensis ranged 1.30-1.61, but during the IV-V molt head capsule dimensions (sexes pooled) increased by a ratio of 1.09 – comparable to the magnitude of sexual dimorphism in head capsule size within each of the final two larval instars. Individual rearings coupled with 2014-2016 field surveys in nine other ponds suggest that five larval instars is an obligatory trait of this species at this location. As this is the first confirmed case of five larval instars in a chironomid, the phylogenetic uniqueness of this trait needs further investigation.