Fiji – Yasawas Part 2 – Coral Reefs

I slowly made my way down the Yasawas, stopping at a couple resorts along the way back to the main island. It is impossible to capture how stunning it is to swim out from shore and be surrounded by yards of coral reefs in crystal clear waters.

Although corals can grow in a variety of environments, most coral reefs are found between 30°N and 30°S latitudes. Corals are small animals that capture and eat plankton using stinging cells, similar to jellyfish. However, they also host a type of symbiotic plankton called dinoflagellates. These dinoflagellates perform photosynthesis and produce sugars that corals use for energy to grow, build, and survive. In return, corals provide the dinoflagellates with a safe place to live.

A single coral structure contains hundreds of genetically identical individuals living together as a colony. This cooperative structure allows them to sustain themselves and build the protective coral skeleton that shelters the entire colony. Corals require abundant sunlight and nutrient-poor water to thrive. When nutrient levels rise (particularly nitrogen, phosphorus, potassium, and iron), algae can flourish, overgrow the coral, and block the sunlight they depend on for survival.

coral reefs stretching forever

The beautiful colors of coral reefs come from the dinoflagellates living within them. When ocean temperatures rise too high, the chloroplasts in these organisms become stressed and release oxygen. This oxygen damages the coral’s cells, and the coral expels the dinoflagellates for behaving badly. This process is known as coral bleaching, and such events are becoming more common as ocean temperatures continue to rise in these regions.

Blackback Butterflyfish with corals, Cauliflower Coral, Black-axil Chromises

If the water cools down in time, corals may allow the dinoflagellates to return. However, if the water remains too warm for too long, the corals can become permanently bleached. This is because corals obtain up to 90% of their energy from their symbiotic plankton and often die when that energy source is lost.

Bicolor Blenny, Fiji Tomato Clownfish, Moorish Idol

Coral reefs cover less than 1% of the ocean floor, yet they are among the most important ecosystems in the ocean because they serve as nurseries for many species. They provide shelter and protection where young organisms can hide and grow until they are large enough to fend for themselves.

Orangestripe Triggerfish, Bridled Monocle Bream

Corals are considered to be foundation species, because the entire coral reef ecosystem wouldn’t exist without their skeletons. These animals create an area that allows all these other organisms to thrive.

Blackspotted Puffer, Specklefin Grouper, Longnose Filefish

The corals in these photos are part of a Marine Protected Area. In this case, this means that people cannot fish or remove species from the area. As fish and other organisms mature within the MPA, they gradually move into surrounding waters, where they can help repopulate other regions or become part of the food web for humans and other animals. Marine Protected Areas allow organisms, especially fish, to grow large enough to reproduce and sustain future generations.

Titan Triggerfish, Bushy Feather Star, Oriental Sweetlips

As always, I went out looking for nudibranchs, and although there weren’t very many, I did manage to find a couple hiding between the corals.

Pustulose Wart Slug, Blue Linckia, Krempf’s Phyllidiopsis

Giants clams of all kinds continue to be my other favorite invertebrate find. The patterns on their mantles are intricately colored and vary dramatically between individuals.

Gigas Giant Clam, Fluted Giant Clam, Gigas Giant Clam

I had heard rumors of some tiny nudibranchs down in the sandy bottoms, so I signed myself up for a muck dive. This is basically looking through sediment for weird, camouflaged organisms. I didn’t find any nudibranchs unfortunately, but I did see transparent shrimp and this tiny, patterned anemone attached to a blade of seaweed.

Sarasvati Anemone Shrimp, Swimming Anemone, Banana Coral

The most ridiculous muck dive find was a giant yellow sea cucumber that was over two feet long. Sea cucumbers feed on detritus (poop and decaying organic matter) from the ocean floor. They ingest sand, digest the organic material within it, and then get rid of the remaining sand out of their back end. Nearby was evidence of its recent activity, a large mound of sandy poop that was at least a foot across.

Herrmann’s Sea Cucumber (over 2 ft long), giant pile of sea cucumber poop (1 ft across)

Fiji Wonderings

Jet-lagged and still coping with time differences, I woke up at 5am to the tapering end of a massive rain storm. I stumbled out of bed, grabbed my headlamp, and pulled my sneakers on to head out on a “mountain” hike. Mountain is truly a bit of an exaggeration for a steep hill located on a small island in the Yasawas of northwestern Fiji. Winding behind the staff quarters, I glanced up to a see a 4-inch spider hovering around her eggs high up in a web stretching from the fence to the building behind it. As I left the property, the hike headed mostly up at an angle that would’ve been challenging on a dry day, but was made even more complicated by the water running through the middle of the path. I eventually just embraced the squishy mud and started making steady progress to the top. Somewhere along the way, I noticed footsteps in the mud, sometimes in a flat shoe, sometimes with toes spread wide. Yet it seemed to be just one person walking due to the gait and placements of the steps.

Through the cover of trees, I walked, stopping briefly to check out a passion flower plant. They all have an outer ring of rounded petals, followed by a ring of slender multi-colored petals sticking straight out. In the scientific literature, these are called corona filaments: corona like the outermost plasma surrounding the sun, filament like the tiny wire that burns so brightly in an incandescent bulb. These skinny petals form a ring around the dangling male anthers, filled with pollen, ready to be brushed away on the back of a visiting bumblebee. The hanging, sticky female stigmas are situated even higher, above the male organs, ready to hold on to pollen from other plants arriving via those same pollinators.

passion flower and passion fruit

I know this plant well since a vine of passion flower grows on my back fence at home. I was confident in my ability to recognize it, but this passion fruit was different. Instead of the round purple fruits that deflate into a squashed balloon when they’re ready to eat, this passion fruit was green and enclosed in a green cage of spiky, sticky protrusions clearly meant to protect. It looked other worldly and yet this was natural armor, created through years of gradual modifications. Whenever I see a new plant, my mind jumps to two questions: Can I eat it? Is it native? 1 Out there, on the “mountain,” I had no phone service, so I shelved these questions for later and kept walking.

I passed the one other person who climbed the mountain before me that morning. He was wearing flip flops and the footprints from the start of the hike started to make sense. When he got to the muddy part of the hill, he took off his sandals when they got stuck and tried a barefoot approach. He nodded a hello and I did the same, silently acknowledging the strange and awkward fellowship of two random people who felt the need to rise before the sun was up in order to solo climb a ridiculously muddy hill during a break in a downpour. No words were necessary, this was not the time to disturb his serenity or mine. I followed the trail towards the open ocean to the north, which was rapidly appearing in my view along the edge of the hillside.

view towards the northern end of Nacula Island

As I squatted to rest and embrace the view, I noticed the reddish brownish rock beneath my feet. Volcanic in origin, probably basalt, formed underwater and then brought up to the surface. I had more questions: How did these volcanic islands pop out of the Indian Ocean? Were they formed from hot spots or is this on the edge of a subduction zone? How long ago did this happen? 2 Curiosity is a restless creature. Once you open the gate, it carries you off with no promise of where you’ll end up.

The view over the north side of the island was stunning. The sun had risen during my hike, but it was hidden behind the clouds. The path forward looked like a solid descent to the ocean on the north side, and I wasn’t in the mood to climb back up, so I turned around and started hiking back. On the way, I saw a millipede crossing my path. Or was it a centipede? Was it poisonous? Is it centipedes or millipedes that are poisonous? I wasn’t sure what I was looking at, so I snapped a photo to identify on iNaturalist later. 3

Before I reached the steep hill back down to the hotel, I came across a hala tree which was identifiable because of its bumpy faintly-pineapple shaped fruit. They’re very common throughout the Pacific Islands because they grow in rough soil and salty environments. On a previous trip to Hawaiʻi, I’d learned that Polynesians used to weave the leaves into giant canoe sails. These were the sails that took early explorers thousands of miles across the ocean.

basalt, Rusty Millipede, hala fruit

Sometimes I just have to laugh. I had gone on this hike to clear my mind and relax. By the time I returned to the hotel, I had ten more questions that I wanted answers for. But that’s also the beautiful part of staying curious about the natural world, it keeps me present in the world around me. All the questions are both grounding and expansive, somehow at the same time. When I make a new friend, it takes an investment of time, energy and care before the other person trusts me. Meeting a place is very similar, and slowly, little by little (with a little help from the internet), it reveals its secrets.

Footnotes

  1. The type of passionflower in Fiji I saw is known as Passiflora foetida, the stinking passionflower. While waiting for the sun to go down for my night scuba, my scuba guide confirmed it is edible, but not during the season that I was visiting. This species is not native to Fiji, but is native to the southwestern United States, parts of the Caribbean, Central America and South America. ↩︎
  2. The Yasawa Islands formed about 8 million years ago as part of a volcanic island arc. They developed above a subduction zone, where one tectonic plate was forced under another. As the descending plate sank into the mantle, it released water and other fluids, which lowered the melting point of the overlying mantle. This caused partial melting and generated magma that rose through the crust and erupted first on the seafloor and later above sea level, building the islands. ↩︎
  3. It was a Rusty Millipede (Trigoniulus corallinus). ↩︎

West Coast Trail

In August 2023, I hiked the West Coast Trail on Vancouver Island. It’s probably my favorite backpacking trail to date and I would do it again in a heartbeat.

So many folks on the trail were surprised when I told them I was doing the trail solo and how that took a lot of courage. But what I think it really takes is trust – trust in yourself and your abilities (both physical and mental) and also trust in other people you meet on the trail. I gained a whole trail family as well as a bunch of bruises and blisters (yellow jackets are evil and so are my boots) but I couldn’t be happier. Forever grateful for this healing journey and thankful to the Huu-ay-aht, Ditidaht and Pacheedaht First Nations who continue to steward this land.