We strive to accurately understand the biology and status of freshwater fishes native to North America, especially those species that have been historically underappreciated and understudied. With updated and accurate life history information for these less-recognized species that are still vital to native ecosystems, resource agencies will be able to make defensible management decisions towards sustaining these resources. Without such data, informed management is impossible and native fish stocks are easily pushed to the brink. As harvest methods, interests, and technologies evolve it becomes increasingly crucial that fish and fisheries are studied before it is too late.
A case in point
The bigmouth buffalo
Take for example the bigmouth buffalo. Previous to research published in 2019, this species was thought to be fast-paced and short-lived (10-20 years maximum longevity), even though these assumptions were based on inadequate, outdated fish-aging techniques, and this species was little studied. Using the accurate and precise aging method for otolith-bearing fish species (otolith thin sectioning) bigmouth buffalo were found to reach 112 years of age – one of the longest-lived fishes ever known – and this aging protocol was validated. Not only that, this 112-year-old record-setter was in prime condition until she was shot by bow and arrow – the species’ natural age ceiling is still not known. Furthermore, some areas in Minnesota contain old-growth populations, wherein 85-90% of individuals are between 80-115 years old, indicating decades’ long recruitment failure since the 1930s. Like sturgeon and sea turtles, bigmouth buffalo are long-lived and may have recruitment gaps that span decades until optimal spawning conditions occur.
Such old-growth populations are at extreme risk of decimation when harvest is liberal, much like clear-cutting a grove of century-old oak trees. This is currently the case for bigmouth buffalo in Minnesota as their management still reflects the inaccurate life history information previous to 2019, and does little to monitor the impact of the new and rapidly growing sport of night bowfishing (where fish are shot by bow and arrow with the aid of powerful spotlights at night). In this sport bigmouth buffalo can be taken in huge numbers, with some hauls exceeding a ton (~100 fish) per night. There are currently no limits, no mandatory harvest-reporting mechanisms, nor regionally-specific regulatory measures on the recreational take of bigmouth buffalo in MN, even as the sport of night bowfishing has exploded in popularity in recent years since it was legalized in 2010. Populations of bigmouth buffalo were already in decline in parts of MN prior to the onset of night bowfishing.
This matters because bigmouth buffalo are native to North America. They belong here and are important to the natural food web. Native Americans utilize bigmouth buffalo and they are important and abundant in their culture. Bigmouth buffalo have been known as “in decline” since the 1970s in parts of MN, ND, and Canada because of dams, invasive Common Carp, and overharvest. They also compete directly against invasive carp including the invasive Asian Carp (Bighead and Silver) that are spreading into MN. Bigmouth buffalo also feed on invasive zebra mussel larvae (veligers), and bigmouth buffalo young themselves are food for walleye, northern pike, catfish, gar, and other predatory fish. Bigmouth buffalo are also highly valuable to an inland commercial fishery where they are sold for food, and they have also rapidly become a prized game fish for bowfishers who shoot animals for sport. There are also traditional anglers, the general public, and fisheries biologists alike who appreciate this animal for their large size, mysterious nature, and exceptional longevity. If business continues as usual in certain regions, this public resource could quickly be lost for all of the stakeholders involved, which would be a lose-lose situation for everyone.
A 90-year-old male bigmouth buffalo riddled with orange spots
As is clear from this case study, accurate age information is crucial to sustainable fisheries. Thus, our lab’s focus is on the accurate and precise age analysis of harvested species.