We finished up our time in the Papahanaumokuakea Marine National Monument this afternoon, and have begun the roughly 450 nautical mile trek south from French Frigate Shoals to Johnston Atoll, the most isolated atoll on the planet. We should arrive Thursday morning, ready for operations. From a marine fauna standpoint, Johnston Atoll is very interesting, especially in the relationship between the fauna found on the Atoll, and the fauna found within the reefs of its closest neighbors. Looking at a simple chart of oceania,, one might be tempted to look at Johnston and say, that looks like it might be influenced from the Marshall Islands (to the west), or the Line Islands (to the South and East). This might seem obvious, since the center for marine biodiversity is generally considered to be the “Coral Triangle” of Indonesia, the Philippines and New Guinea. Species diversity declines as one moves outward from this epicenter, generally with lower diversity the farther away you travel. The Hawaiian Archipelago has a relatively limited number of reef fish species for example, when compared to the Marshall Islands, the Line Islands, Micronesia etc. Since Johnston is geographically closer to the epicenter, an assumption could be made that there is more biodiversity there than in Hawaii.
This assumption is wrong. There are only around 300 species of inshore reef fishes at Johnston, and the fish found there are more closely related to the Hawaiian Island populations than to those of the Marshall or Line Islands. Many species considered endemic to Hawaii are found also at Johnston, but in many cases seem to be seeded from the Hawaiian Islands population, rather than from established local populations. We know there is an exchange between French Frigate Shoals and Johnston, as they are the closest neighbors. Both share large spreads of Acropora corals, and the fish that feed exclusively on those corals, or have adapted to feed in and around the corals distinct physiology.
We did get in a great dive today at French Frigate. The morning deep team missed the drop by only a small margin, but the presence of a strong deep current prevented them from exploring an enticing ledge, wall system. They ended the dive early and had long faces during the midday team exchange. The afternoon team then had low expectations, which were easily bested by a perfect drop, little current, great visibility and interesting terrain to explore. We didn’t record any new species for our lists, but reaffirmed many that we only had one record for, thereby strengthening our dataset.
I have attached a few stills from the dive today; one of interest was the long nose hawkfish, (Oxycirrhites typus) which we found today on a little wall by himself. Usually a strong commensal with pairs or trios living in black coral bushes, this individual was alone, no coral in sight. The triggerfish is the male Blue Throat (Xanthichthys auromarginatus) – I believe I earlier sent out a picture of his goth lady with her black lipstick. I experimented with a GoPro camera attached to my large camera housing to get a different perspective. I need to work on the placement, but I think the shot may prove useful when putting together an edited production. The little squat lobster is a cute fella that I have no idea what to call, so we’ll just call him a squat lobster. A couple of my dive mates, Jason Leonard (fish guy) and Kelly Gleason (marine archeologist, wait, what?) are also included. I am trying to teach my underwater models to have Explorer’s Eyes!