Scientists have found an unexpected ally beneath the surface of our oceans – fish. Much like tree rings holding the secrets of climate change on land, fish growth rings found in their tiny ear bones called otoliths offer valuable clues to our planet’s fluctuating climate.
Researchers from the University of Arizona led by Bryan Black, an associate professor specializing in dendrochronology (the study of tree rings) have pioneered a technique to analyze fish rings similar to those found in trees. This innovative approach provides a unique window into understanding how climate change impacts fish growth and consequently aquatic ecosystems.
Otoliths with their growth rings become archives of the environmental conditions fish experience. The process known as “crossdating” matches growth patterns among fish of the same species similar to how trees rings vary with climate conditions. For instance, trees in regions influenced by rainfall exhibit wide rings during wet years and narrow rings during dry years.
This technique ensures precise identification of the calendar year for each fish ring enabling scientists to build accurate growth histories. Bryan Black’s focus on species like the splitnose rockfish, a non-migratory North Pacific species has provided valuable insights into annual growth increments.
The study extends beyond simple age estimates delving into how climate events including marine heatwaves impact fish growth. Black’s research utilizing archived otolith collections dating back to the 1970s contributes to a global network spanning Europe, Australia, the US and Canada. This network offers a comprehensive understanding of how climate drivers affect marine and terrestrial environments.
Looking ahead Bryan Black aims to explore the influence of climate events on fish growth particularly in heavily fished populations. By comparing responses between exploited and less-exploited fish populations, the research aims to untangle how these creatures adapt to extreme climate events and intensive fishing practices.
In a world grappling with the consequences of climate change, these fish growth rings emerge as unexpected storytellers providing critical information that could aid in preserving our oceans and their diverse ecosystems. As scientists continue to unlock nature’s secrets, the collaboration between dendrochronology and marine biology opens new avenues for understanding and mitigating the impacts of a changing climate.
