Bigmouth buffalo
The bigmouth buffalo (Ictiobus cyprinellus) is a fish native to North America. It is the largest North American species in the Catostomidae or "sucker" family, and is one of the longest-lived and latest-maturing freshwater fishes, capable of living 127 years and reproducing infrequently. Even at a century old they show no age-related declines, but instead improvements relative to younger individuals, making this species a biological marvel. It is commonly called the gourdhead, marblehead, redmouth buffalo, buffalofish, bernard buffalo, roundhead, or brown buffalo. The bigmouth buffalo is not a carp, nor is any other fish in the sucker family. Although they share the same order, each belong to different suborders and are native to separate continents. The bigmouth buffalo is typically a brownish olive color with dusky fins, but can vary greatly in color across individuals including melanistic, golden, and even xanthic color morphs. Like other catostomids it has a long dorsal fin, but unlike all other extant species it has a terminal (forward-facing) mouth reflecting its unique, pelagic feeding ecology. It is the largest of the buffalofishes and can reach a length of more than and in weight. Generally it lives in lakes, or in sluggish areas of large rivers. Bigmouth buffalo populations have been in decline in the northern extent of their range since the 1970s, including Minnesota, North Dakota, and Canada. A 2019 study documented their late maturity, centenarian longevity, and that several populations in northwestern Minnesota are composed mainly (85–90%) of individuals more than 80 years old, indicating recruitment failure since the 1930s. A 2021 study from North Dakota also revealed a slow pace of life including late maturity, decadal episodic recruitment, and a relatively large group of old-growth individuals. A 2022 study from Saskatchewan, Canada revealed remarkable tendencies of the bigmouth buffalo including a supercentenarian lifespan, skip-spawning related to water levels, proximate mechanisms underlying failed recruitment, extreme episodic recruitment, and late maturity—all characteristics that make this species extremely vulnerable to overfishing, habitat degradation, and invasive species.