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 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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The bowfin Amia calva is an amiid (Amiiformes) relict native to North America. It is the last surviving member of the Halecomorphi, a group of fishes that evolved more than 250 million years ago. Despite the phylogenetic significance of the amiids in vertebrate evolution, little has been published about their age and growth. Recreational bowfin harvest is currently unregulated throughout most of the USA, yet new recreational fisheries are emerging. As such, bowfin are increasingly harvested by sport bowfishing without limit, in addition to their growing commercial harvest for caviar. From 2017 to 2021 we studied a total of 81 bowfin from 11 populations across the east-west gradient of Minnesota within a narrow latitudinal margin (<50 km) of the 46th parallel north. We compared the allometry and translucence of bowfin asteriscus, lapillus and sagittal otoliths and found the lapillus otoliths provide consistent readability for age estimation despite being the smallest of the set. Size-at-age data derived from otoliths indicated that bowfin are sexually dimorphic in asymptotic length and may live up to 33 years, which is 15 years longer than previously estimated in wild populations, but comparable to what has been reported in captivity.Overall, 28% of the otolith-aged fish were estimated as older than the previously reported maximum age for wild bowfin populations. Our findings suggest that the bowfin life history may exhibit slower growth, greater longevity, and more variable recruitment than previously recognized, which sets the stage for more otolith-derived population demographics across their range and age validation study. Our results have direct implications for conservation of bowfin, especially amidst the increasing rates of exploitation during the bowfishing era. STATEMENT OF SIGNIFICANCEBowfin otoliths have been abandoned in previous age studies. We present the first thorough analysis of all Bowfin otoliths and find that their lapilli and asterisci are especially useful for age estimation despite being smaller than the sagittae. Using otolith-derived data we find that Bowfin may live 33 years, which is ~2-3 times longer than previously estimated for wild populations, but comparable to known-age Bowfin lifespans in captivity. Our findings are especially relevant because Bowfin are becoming sportfish via bowfishing while also subject to a growing caviar fishery.