Seven government scientists, who were on teams that had been studying and protecting endangered monk seals, green turtles and sea birds at French Frigate shoals East Island for decades, had to evacuate East Island on October 2 ahead of category 4 hurricane Walaka, one of the strongest hurricanes on record in the central Pacific. The island was the breeding ground for about half of Hawaii’s endangered green sea turtles and 30% of Hawaii’s highly endangered monk seals. When scientists recently examined satellite photos after the hurricane they discovered the whole half-mile long 400 ft wide island had vanished.
The photo above shows that strong waves from the south pushed the sand off the reef it overlaid and drove it into a shallow water trough to the north of the reef. The sand was not lost to deep water, but the island may never reform, because sea level continues to rise and the living corals on the fringing reefs were likely devastated by the hurricane. Without climate change and sea level rise, trade winds and long period swells would likely push the sand back over the reef rock and reform the island.
Over time, when sea level is stable, storms, swells winds and overwash create islands. The northwest Hawaiian islands were once large islands like the main island, but erosion and the cooling and sinking of the crust submerges the volcanic bases of all of the islands over periods of ten million years of more. However, coral and coraline algae growing on top of the volcanic core have been able to maintain islands long after the volcanic base submerged. That is, until now. Rapid sea level rise, ocean warming and acidification, and increasingly intense storms are killing the coral that protects and maintains low tropical and subtropical islands worldwide. Thus the breeding grounds for endangered sea turtles, monk seals and many birds are vanishing. East island is the third island in the northwest Hawaiian islands to be wiped out. Human activity, especially night lighting, makes large inhabited islands unsuitable for turtle and bird breeding, so there is no good substitute breeding grounds for lost uninhabited islands.
Under good conditions, coral takes decades or more to recover from a major hurricane. I visited a research station on Moorea, Tahiti, which was studying coral recovery, a decade after the big hurricane and the coral was still devastated. Unfortunately, the corals of the northwest Hawaiian Islands were recently hard hit by coral bleaching caused by an ocean heat wave in 2015 to 2016, so the reefs were in bad shape before Walaka hit. Scientists will study the damage to the other islands of the French Frigate shoals to see how well they are doing, but this has been hard news for them to take.
French Frigate Shoals used to be the largest breeding ground for Hawaiian monk seals but has seen a decline in recent years. Still, about 30 percent of the population is born there on average, Littnan said.
Roughly 1,100 of the entire population of 1,400 Hawaiian monk seals live in the Northwestern Hawaiian Islands. The rest live in the Main Hawaiian Islands.
Littnan said monk seals of all ages have successfully weathered severe storms for years but he won’t know the effects of this storm until researchers return next year to survey the population.
Charles Littnan, the director of the National Oceanic and Atmospheric Administration’s protected species division, told HuffPost it will likely take years to understand what the island’s loss means for these imperiled species.
The biggest concern, he said, is the persistent loss of habitat, which has been identified as a significant threat to monk seals and green sea turtles. Nearby Trig Island was also lost beneath the surface this year, not because of a storm but from high wave activity.
“These small, sandy islets are going to really struggle to persist” in a warming world with rising seas, Littnan said. “This event is confronting us with what the future could look like.”
French Frigate Shoals is the nesting ground for 96 percent of the Hawaiian green sea turtle population, and approximately half lay their eggs at East Island. Historically, it has been the “single most important” nesting site for the turtles, he said.
On the island of Kauai where I lived for 10 years there is an effort to improve breeding conditions for turtles, seals and birds. The National Tropical Botanical Garden keeps Lawai beach dark and has volunteers watch to protect nesting turtles on moonlight summer nights. I participated, but the turtles didn’t come that night. NOAA has established areas of protection where monk seals have come to give birth on the main islands. When I was there and area called baby beach in Poipu was protected from hordes of tourists so that a mother seal could give birth and raise her baby. And don’t mess with mother seals. A tourist illegally got in the water near her baby and she bit him in the rear.
Sanctuaries and bird rescue stations have been set up on Kauai. I personally rescued a young shearwater that had been disoriented by lights and took it to the rescue station at the firehouse. There are things we can do collectively and individually. The situation isn’t hopeless, but it is dire.