Tag Archives: coral reef

Coral, Fish, and Jellies

An important part of natural resource management is measuring exactly how much of that resource is present to determine how it changes over time. For a marine biologist this means scuba diving and counting all the live hard coral and soft coral under a transect line (a huge 50m tape measure)

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John counts coral and records the data on a plastic underwater dive slate. Did you know that pencils write above water and below?!

The second part of our assessment is a fish population survey, where we swim along the transect line and count every fish and record the species and size class. The problem of overfishing in the Philippines means that most fish are <10cm in size, big fish are rare.

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Notice the lionfish hiding upside down under the beautiful colony of boulder coral. Lionfish may look majestic, but those dorsal spines pack some painful venom, so don’t touch!
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An Orange skunk clownfish (Amphiprion sandaracinos) stares at my underwater camera. This fish is named for the white line that runs along its dorsal ridge, like a skunk’s white stripe.
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That scuba diver on the left is ME and that sting ray in the distance is a MANTA RAY!!! Checkmark on my life list, that moment was incredible!

The manta ray photo above did not happen during our coral reef surveys in Romblon. These creatures are a rare find, but Manta Bowl dive site in Donsol, Sorsogon is a great place to find one if it is also on your life list.

Dive assessments and manta rays…if only that was the happy ending, instead our team of scuba divers emerged from our last dive with a super itchy full body rash!

After some investigation we determined that our unfortunate participation prize was “Sea Bather’s Eruption,” a rash caused by invisible jellyfish larvae that get caught in your clothing and become stressed. The stress triggers their stinging cells to fire, which condemned us to two weeks of intense itching! 😦

Jellyfish spawn in the warm waters of summer. We were particularly unlucky because there was no current whatsoever on our last dive. My best advice to avoid 2 weeks of scratching: stay low in the water column if it is the season for jellyfish larvae. I was feeling somewhat cold and tried to stay in the higher warm water, but if you dive below the thermocline you may avoid the worst of their itchy wrath.

Las Tres Islas…pockets of pristine beauty!

Conception, Corcuera and Banton. Las Tres Islas. The three northern islands of the province of Romblon, reachable in 1 to 3 hours by a banka (small Filipino boat) depending on the size of the waves. The three most remote municipalities of Romblon, but potentially the most beautiful!

Last week I conducted coastal resource assessments of coral reef, seagrass and mangrove habitats with the help of 5 other staff in my provincial office. The most exciting and most tiring of these was the manta tow.

Manta Tow means holding on to the manta board and being dragged behind the banka (boat) over the coral reef to estimate coral coverage and locate regions of reef, sand, seagrass…etc.
Manta Tow means holding on to the manta board and being dragged behind the banka (boat) over the coral reef to estimate coral coverage and locate regions of reef, sand, seagrass…etc. Later we will return to the islands with SCUBA gear to assess coral cover on specific identified reefs and fish abundance.
Hold on tight! Over 6 days we surveyed the circumference of 3 islands amounting to 90km.
Hold on tight! Over 6 days we surveyed the circumference of 3 islands amounting to 91km.
Our data sheet with categories for percentage of live hard coral, soft coral, dead coral, dead coral with algae and sand/rubble.
Our data sheet with categories for percentage of live hard coral, soft coral, dead coral, dead coral with algae and sand/rubble.

Accomplishments from our week of assessments:

  • 91km of coastline assessed by manta tow
  • 27 Seagrass surveys
  • 4 Transects laid in mangrove habitats
  • 34 Meetings held with local fisherfolk

Observations: 42 sea turtles, mostly green

Positives: Beautiful hard and soft corals with reef quality in some locations comparable to Apo Island Marine Sanctuary, which is one of the Philippines’ oldest and most renowned has been protected since 1985. With several deeper reefs the islands offer great potential for dive tourism.

Threats: Many crown-of-thorns were observed, along with coral bleaching and algal overgrowth, cuttings in some mangrove habitats, coastal pollution and future development.

Next steps: Crown-of-thorns removal and improvements to the management plans for existing protected areas. As a Peace Corps volunteer I will work with the provincial office to meet with the municipal mayors, other staff, and local fisherfolk to share these results and implement protection and restoration where it is needed.

WATCH THE VIDEO FROM OUR ASSESSMENTS: https://www.youtube.com/watch?v=h2G9qsx8u1w

Photo credit: Loren Tihanyi
Photo credit: Loren Tihanyi

And how would you like your Giant Clam?!

The Giant Clam, threatened by over harvesting for food and aquarium trade, it is a marvel of the Indo-Pacific.
The Giant Clam, threatened by over harvesting for food and aquarium trade, it is a marvel of the Indo-Pacific.

Last week, I was served Giant Clam. How did an endangered species find its way to my lunch table?! This particular clam was one of many marine casualties from a recent boat grounding. I was called in to conduct the damage report after a large tugboat ran aground inside of a protected fish sanctuary, and left a large hole where there was once reef.

This hole is 336 square meters or about the size of 11 parking spots, where there was once coral.
This hole is 336 square meters or about the size of 11 parking spots, where there was once coral.

Assisted by three Filipino free divers, we surveyed the area taking underwater measurements with a large 50m transect line of the damage area. Secondly, I took many photos with my underwater camera to document the destruction. Finally, I conducted a visual survey of damaged species including displaced fish species, sea stars, corals, sponges and most notably the Giant Clam.

These branching corals grow about 10cm per year, but boulder corals grow less than 2cm per year, meaning that this wreck will take 50 years or more for recovery.
These branching corals grow about 10cm per year, but boulder corals grow less than 2cm per year, meaning that this wreck will take 50 years or more for recovery.

The Giant Clam can live to be over 100 years old, reaching sizes of up to 4 feet and more than 440lbs. Luckily, the clam damaged in our boat grounding was only about the size of a basketball, but that is still much larger than any clam I had ever seen in the Atlantic Ocean! Giant Clams attain such impressive sizes through a symbiotic relationship with zooxanthellae, an algae that lives inside of its tissues, giving the clam its color. This is the same algae found inside the stony corals which build coral reefs. Zooxanthellae captures light energy and produces food for the clam through photosynthesis, while the clam provides a home for this algae. Did you know that no two Giant Clams have the same color pattern?!

The Giant Clam damaged by the boat grounding.
The Giant Clam damaged by the boat grounding.

Here is more info about the Giant Clam as well as more cool photos: http://animals.nationalgeographic.com/animals/invertebrates/giant-clam/

Field Trip

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The past day we were on a field trip to Candelaria, where we snorkeled an effective MPA (marine protected area), walked through a mangrove nursery, and stopped to visit a sea cucumber breeding center. The photos were taken at the sea cucumber center and I am holding almost full grown sea cucumber as well as red algae. The sea cucumbers take 8 months to grow from eggs to adults. They feed on dead algae and are exported for food in Asian markets. The red algae, I am holding is also sold as food and can be used for the production of various other products including toothpaste and cosmetic procedures. I collected several different species of sea cucumbers while snorkeling in the seagrass and coral reef habitats just off the shore where I am currently living. I used my samples for demonstration during our recent youth camp. More updates and another video coming!