Continuing the previous day’s exploration of Palau’s Southern Rock Islands, we met again with Ron Leidich and departed for Risong Bay. After a short boat ride, we paired up into kayaks awaiting us beneath eroded overhang of an island. Ron explained the geological history of the islands, describing how thousands of years of coral growth around volcanic structures of the tectonic subduction zones were pulled deeper into the ocean and then forced back up to the surface, creating the limestone structures we know today. Erosion caused by tides, rain, organismal activity, and humic acids in the decaying leaf litter shaped these coral masses into forms of steep rock faces and undercut edges, an entirely unique environment from the main Palauan island of Babeldaob.
At our first stop, King Fisher Bay, we were fortunate enough to catch a glimpse of Palau’s evasive endemic national bird, the Palauan Fruit Dove. The birds are so rare that some Palauan’s have never even seen one.
We paddled further throughout the maze of islands and reached a no motorboat zone that led us to Mandarin Fish Lake, named after the multicolored fish that often reside in the large brain corals growing in the small marine lake. Although we never spotted the fish, we were able to explore and discover several other unique biological and geological features such as a salt waterfall with a tide dependent direction of flow and a sea crate that slithered past our kayaks before we too began to explore the area underwater. Secluded in a location that sees little tourism and is sheltered from storms and waves, the corals in Mandarin Fish Lake were some of largest and healthiest corals we had seen so far. The addition of freshwater from the rain from the previous night also created obvious halocline layers in the lake caused salinity difference between the first few feet of water and the water further down.
The next area was much smaller and secluded compared to the previous two. With the help of a large wooden ladder, we accessed the so-called Sunken City Lake. Hidden from poachers, and access only granted to those who are willing to climb over sharp limestone, the lake has harbored a brood stock of giant clams for the past few years. The presence of an underwater siphon channel leading to the main bay, which allows larval clams to pass, creates an ideal nursery for rehabilitation of the threatened group of bivalves. We got to help plant a few younger clams among the beautiful older clams.
We enjoyed some bento box lunches and diving competitions off the boats before exploring yet another bend in the continuous twists and turns of the Rock Island Marine Reserve. The small cove, colloquially known as Fish Pond, had a rich past. Historically, it was used by the Japanese for marine aquaculture so successfully that production became a profitable export. As we had seen throughout the whole trip, the tropic environment is quick to swallow and degrade, which we could see more evidence of from the WWII shipwreck covered in coral and clams at the bottom of the lake. Palau, although small, had an especially deep history relating to WWII.
Leaving the kayaks behind, we traveled to a fringing reef that we were told was decimated by Typhoon Bopha, ten years prior. Our first look through our snorkel masks was an incredible tell of the reef’s capacity to recover. Large boulder sized corals the size of small cars and fields of branching acropora corals hosting an array of fish including moray eels and rare rock mover wrasse kept us entranced until it was time to ride home. The end of the day consisted of naps and exciting reflection of our Rock Island adventures.