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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.

High‐resolution radiocarbon (14C) analyses on a coral core extracted from Guam, a western tropical Pacific island, revealed a series of early bomb‐produced 14C spikes. The typical marine bomb 14C signal—phase lagged and attenuated relative to atmospheric records—is present in the coral and is consistent with other regional coral records. However, 14C levels well above what can be attributed to air‐sea diffusion alone punctuate this pattern. This anomaly was observed in other Indo‐Pacific coral records, but the Guam record is unmatched in magnitude and temporal resolution. The Guam coral Δ14C record provided three spikes in 1954–1955, 1956–1957, and 1958–1959 that are superimposed on a normal 14C record. Relative to mean prebomb levels, the first peak rises an incredible ∼700‰ and remained elevated for ∼1.2 years. A follow up assay with finer resolution increased the peak by ∼300‰. Subsequent spikes were less intense with a rise of ∼35 and ∼70‰. Each can be linked to thermonuclear testing in the Pacific Proving Grounds at Bikini and Enewetak atolls in Operations Castle (1954), Redwing (1956), and Hardtack I (1958). These 14C signals can be explained by vaporization of coral reef material in the nuclear fireball, coupled with neutron activation of atmospheric nitrogen (14C production), and subsequent absorption of 14CO2 to form particulate carbonates of close‐in fallout. The lag time in reaching Guam and other coral records abroad was tied to ocean surface currents and modeling provided validation of 14C arrival observations.

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