The primary cause of reef fish declines across the Hawaiian Islands is overfishing, according to the largest study of its kind ever published.
“This is the most compelling evidence that overfishing is the primary driver of reef fish declines in the main Hawaiian Islands, based on the most robust dataset ever put together for Hawaiʻi, and perhaps the world,” said Dr. Alan M. Friedlander, a University of Hawaiʻi marine ecologist and National Geographic’s Pristine Seas chief scientist. “The data was collected by multiple agencies and researchers since 2000, and is based on more than 25,000 in-water surveys.”
Friedlander is the lead author of a new research paper that compares fish density across the islands by moku, a traditional Hawaiian resource management designation that encompasses several ahupuaʻa.
Data from the study clearly show that the abundance of food fish species (those primarily caught for human consumption) is lower in populated areas, while there is no difference in the abundance of non-food fish species (those not generally targeted by fishing) between populated and unpopulated areas.
This finding strongly suggests that fishing, rather than other human influences such as pollution or habitat degradation, is primarily responsible for the observed differences.
“There have been arguments for decades about the impacts of other factors on reef fish populations, such as sediment, sewage and physical damage to reefs. But these threats would affect all fish similarly,” said co-author Dr. Eric Conklin, marine science director for The Nature Conservancy of Hawai‘i. “The only impact that would affect food fish and non-food fish differently would be direct fishing pressure.”
That does not mean,…