Fighting Harmful Coral Algae With Vacuum Cleaners and Sea Urchins
Hawaiian scientists have successfully tested a novel way to remove an invasive species that was smothering a coral reef off Oahu – vacuuming up macroalgae with a device dubbed the Super Sucker and then releasing baby sea urchins to graze on any algae that managed to sprout back up.
Over the two-year project, the scientists reduced macroalgae cover by 85 percent, according to a study published in the journal PeerJ. During that time, scientists from the State of Hawaii Division of Aquatic Resources and the Hawaii Institute of Marine Biology at the University of Hawaii at Manoa vacuumed up 19,000kg (42,000lb) of algae and released 99,000 native sea urchins over 24,000 square meters (6 acres) of reef.
The result was a decline in macroalgae with no observed negative impact on the reef, researchers said. While rising ocean temperatures from the burning of fossil fuels remain the overwhelming threat to coral reefs worldwide, eliminating local hazards can speed reef recovery from coral bleaching, they noted.
“Local action is instrumental in supporting the resilience of coral reefs,” Brian Neilson, acting administrator of the Division of Aquatic Resources, said in a statement. “This study provides an important tool that can assist in the management and conservation of coral reefs.”
Predicting Fishing on the High Seas
Researchers have created a computer model that predicts the future location of fishing fleets on the high seas – the area of the ocean beyond national jurisdiction – by analyzing environmental conditions that fish and fishers prefer.
The wealth of surveillance data produced and analyzed by Global Fishing Watch and other initiatives have helped identify illegal fishing and have spurred research into fishing on the high seas and its impact on marine ecosystems. Now scientists at Duke University, the University of British Columbia and Dalhousie University have combined Global Fishing Watch data on fishing vessel locations with an analysis of 14 environmental variables, including sea surface temperatures, surface oxygen concentration and particulate organic carbon. The model allowed the researchers to successfully predict the seasonal location of fishing fleets and their targets – tuna and other fish species.
“Fisheries managers can use information regarding the predicted distribution of fishing effort and bycatch species to provide information on the likely location of bycatch, targeted observer coverage or enforcement and partial closures or zoning,” the researchers wrote in a study published in the journal Science Advances. “Further, models of the distribution of fishing effort can be run under different climate scenarios to help understand how fishing effort may shift in the future and affect fishing communities.”
Corals and Zooxanthellae’s Very Long-Term Relationship
Scientists at Oregon State University and Penn State have discovered that the symbiotic relationship between corals and zooxanthellae algae dates to the Jurassic Period, or about 100 million years longer than previously thought.
Corals provide zooxanthellae shelter, and the algae supply corals nutrition and their eye-popping colors. That 160 million-year-old partnership is now threatened by climate change, but the ancient nature of the relationship gives some hope, according to Todd LaJeunesse, an associate professor of biology at Penn State. “Over all of those millions of years, partnerships have faced major hurdles and managed to bounce back,” he said in a statement.