How long do fish live? 10 years? Twenty? Try over 80 years, according to new research on snappers.
Before now, the oldest known snapper was recorded at 60 years old, two decades younger than findings recently published in the journal Coral Reefs. Does this twenty-year age gap matter? According to fisheries scientist and the study’s lead author Dr. Brett Taylor, it matters quite a bit.
Snappers serve as an important food source around the world. Despite the snapper’s importance, the global snapper fishery is, in large part, poorly managed. This, combined with the high market value of some snapper species, led the U.S. National Oceanic and Atmospheric Administration (NOAA) to officially label red snapper as ‘at risk’ for illegal, unreported, and unregulated (IUU) fishing and market fraud in 2015.
Snappers were known to be ‘long-lived’ species before the recent discovery of the 80-year-old fish. In fact, the snapper’s long lifespan is part of what makes the fish susceptible to exploitation. “There is a direct relationship between life span and how quickly a population can replenish itself through reproduction,” explains Taylor. “Long-lived marine fishes have evolved a strategy that allows them to buffer against periods of poor environmental conditions by having lots of mature, spawning individuals present in the populations. This strategy, however, did not evolve alongside the additional pressure of fishing, which directly removes these larger and older fish from the population.”
To better understand the effects of fishing – and potentially overfishing – on snappers, Taylor and his team studied three species of snappers that are not commercially or recreationally fished. “This allowed us to examine something more similar to ‘natural population structures’ that have not been truncated or otherwise affected by fishing pressure,” explains Taylor. With a lack of fishing pressure, knowledge of the age of these snapper species compared to commercially harvested species could provide important insights into the fishing’s effects on exploited snapper populations.
In addition to studying the age of the three snapper species, Taylor and his co-authors looked at whether snapper growth rates or life spans changed with different temperatures. In warm climates, cold-blooded animals like fish must use extra energy to compensate for their warm surroundings.
Before the widespread use of using fish ear stones (otoliths) to determine a fish’s age, in a manner not so different from counting rings inside a tree, scientists largely thought tropical fish were relatively short-lived species. “However, seminal research in the 1980s and 1990s showed us that many types of tropical reef fishes have extended life spans, way past what we previously presumed,” explains Taylor.
While Taylor’s research revealed