Fish in marine reserve off North Kona coast are recovering, surveys find

Signs that fish populations are beginning to recover at the Ka‘upulehu Marine Reserve off the North Kona coast are giving scientists and community members hope after two years of restrictions on fishing.

The Nature Conservancy said just two years into a 10-year rest period at the reserve, dive surveys have found some species of fish have increased by about 30% to 60%.

A committee made up of community leaders decided to put the 10-year rest period in place in an initiative called “Try Wait” after observing fish declines for decades. After numerous public meetings, the state Department of Land and Natural Resources created Ka‘upulehu Marine Reserve in July 2016.

Under the 10-year harvest rules, the public is prohibited from fishing or taking any marine life, living or dead, including coral, rocks, sand and shells, from the reserve’s established rest area, which stretches 3.6 miles along the shore, and extends from the shoreline to a depth of 120 feet.

From depths of 120 to 600 feet, fishers are allowed to use Kona crab nets, a mesh net encircled by a frame, to catch Kona crabs, and hook-and-line methods only to catch 18 specific kinds of fish: ahi, aku, au, ehu, gindai, hapuupuu, kalekale, lehi, mahimahi, nabeta, onaga, ono, opakapaka, roi, taape, tombo, toau and uku.

No other fishing gear is allowed within the reserve, but other recreational activities are allowed.

Violators face citations of $1,000 to $3,000, along with additional penalties for each specimen that is taken, killed or injured. They also could be fined in a criminal citation of $100 for the first offense and more for subsequent offenses. There were no citations issued in the first two years.

Signs of recovery are noticeable, according to some community members.

“We’ve been hearing from longtime fishermen that the area is starting to remind them of old Hawaii,” said Leina‘ala Lightner, a lineal descendant of Ka‘upulehu, in a news release. “Divers who came to our invasive fish removal event last summer said they were seeing big schools of weke, pualu, uhu and manini, as well as healthy coral, limu, opihi and wana. Many of them shared that seeing the recovery completely changed their opinion of the rest area and community-based fishery management.”

Historically, the area was known for its near-shore fish species, including moi, akule and manini, as well as off-shore opelu, according to a detailed summary prepared by the Kaupulehu community. The fishing grounds were cared for by several generations of local Hawaiian families, many of whom are still there today.

Within the last 40 years, however, many of these families noticed drastic declines in their ocean resources.

The Nature Conservancy’s 2018 surveys corroborated what community members were seeing, according to Chad Wiggins, Hawaii island marine program director.

“On more than 183 dives over seven miles of coastal reefs, we observed more fish — fish we hadn’t seen in the area before — and bigger fish,” said Wiggins in the news release. “While it is too early to determine the long-term effects of the rest area, these signs of recovery show promise for the community’s goal of supporting a sustainable subsistence fishery in the region.”

TNC said base-line surveys conducted from 2009 to 2016, before the rest area began, demonstrated no difference in reef fish communities inside and outside the rest area.

Data from September 2018, however, showed that populations of some fish, including prized species of wrasses, parrotfish and surgeonfish, were increasing. The data also showed increases inside the rest area were higher than in adjacent areas.

Specifically, The Nature Conservancy surveys found the greatest increase, at 62%, for some wrasses, which include the hogfish, a 46% increase in some surgeonfish, such as kole, and 30% increase in some parrotfish inside the rest area.

There also was evidence of fish populations increasing just outside the reserve boundary.

The Nature Conservancy said resting an area is one of the best ways to increase fish populations in coral reef ecosystems, an important step to consider, given that recent science has shown populations of some of Hawaii’s popular reef fish have declined by up to 90%.

While these initial surveys seem promising, scientists warned there is still a long way to go.

“This is preliminary data, and these fish have a long way to go before they are fully recovered,” said Eric Conklin, TNC’s Hawaii director of marine science. “But after decades of documenting decline for highly prized food fish like uhu (parrotfish) that are so important in keeping reefs healthy, it’s a big step in the right direction.”

BY THE NUMBERS

The Nature Conservancy’s 2018 surveys found the following at Ka‘upulehu Marine Reserve:

62%

Increase in some wrasses — hogfish pictured — inside the rest area, and 3% outside

30%

Increase in some parrotfish — uhu pictured — inside the rest area, and 3% outside

46%

Increase in some surgeonfish — kole pictured — inside the rest area, and 21% outside

Evidence of spillover, or fish populations increasing just outside the reserve boundary

Source: The Nature Conservancy