I was fortunate to be able to visit these islands many times on an expedition ship.
Kerehikapa Island and surrounding Islands are part of the Arnavon Community Marine Conservation Area (ACMCA). They are located in the Solomon Isands.
The protected area encompass 40,000 acres, including 3 small uninhabited islands, and surrounding coral reefs. The U.S.A based nature Conservancy helped three communities (Katupika, Kia and Wagina) came together in 1995 to protect the Arnavon Islands. It has been claimed that in the ten years since the ACMCA was established, there has been an increase of 400% in hawksbill sea turtles nesting on the islands. They have also recorded an increase in populations of coral reef fish and commercial species of marine invertebrates. And certainly when one snorkels there, you can see larger fish and food fish that are sometimes lacking or skittish in other parts of Melanesia. For example, when snorkelling there, I have seen huge schools of Hump-headed Parrotfish, as well as foodfish such as Diagonal-Banded Sweetlips, and other Sweetlip species.
As a visitor, there are a few interesting things to see. First, it is a
protected reserve with no one here but the rangers; there are no
villages, no fisherman; this is a rarity in Melanesia.
The snorkelling is good; the clarity is not as high as many other areas in the Solomons, but there are some big fish (see above).
One of the islands has a population of nesting Melanesian scrubfowl.
The main island with the ranger station has a beautiful tidal lagoon with clear water and mangroves. There is good for birding along the beach, with species such as fantails, parrots...
However, the highlight for most people is the turtle nesting...
One of the most important aspects of the islands are their status as a turtle hatchery. The species that breed here include the Loggerhead, Green and Hawksbill turtles.
Access for an independent traveller is difficult, I would imagine! Coral Princess Cruises goes there about once a year, on their Melanesia trip. (However, it is wise to check their itinerary before booking, as it does change.)