Seaweed Farming

Our boat to Sibuyan. We needed a backhoe to unload all of our supplies.
Our boat to Sibuyan. We needed a backhoe to unload all of our supplies.

This past weekend, I traveled to Sibuyan Island, considered “the Galapagos of the Philippines” for its endemic terrestrial diversity. While I hope to return in the summertime to hike the infamous Mt. Guiting Guiting (6,752ft), the objective of this trip was distributing materials for seaweed farming to local fishermen as an alternative livelihood project. These materials are provided for free to the fisherfolk families as compensation for damages to the fishing industry in response to Typhoon Yolanda and also as a means to reduce pressure on declining fishing populations.

Rope, twine and floatation rings were distributed to fisherfolk after a training session on seaweed farming methods. Here is the basic construction of the farm: a net system that has seaweed seedlings tied in rows, and grows in the ocean just off shore.

In 2009, seaweeds were the 3rd largest fisheries export from the Philippines after tuna and shrimp.* The seaweeds grown are often shipped to France, Denmark, Japan, USA or UK after processing in the Philippines. Although raw seaweeds are used for consumption, died seaweeds are often processed for carrageenan, commonly known as seaweed flour, or kelp powder and in a huge variety of products.

What everyday goods are made from seaweed components? Toothpaste, shampoos, ice cream, yogurts, pill capsules, paints and much more! Eucheuma seaweed is a commonly farmed red seaweed, however many different types of seaweeds can be farmed. Check out the link below for more info.

*http://region5.bfar.da.gov.ph/PDF/Seaweed.pdf

Ma'am Rita teaching a fisherman how to attach seaweed seedlings to the rope net.
Ma’am Rita teaching a fisherman how to attach seaweed seedlings to the rope net.
Briefing the fishermen on farming practices before dispersing materials. Notice the stacks of materials on the right ready for dispersal.
Briefing the fishermen on farming practices before dispersing materials. Notice the stacks of materials on the right ready for dispersal.

Crown-of-Thorns

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The Crown-of-Thorns (CoT) sea star (Acanthaster planci) can pose serious threat to Pacific coral reefs. The CoT varies from traditional sea stars in that it may have anywhere from 7 to 23 limbs and possesses numerous, long, sharp, toxic spines. In normal quantities this invertebrate is an appropriate part of the Pacific reef ecosystem. However, recent, increased, massive outbreaks of CoTs are highly problematic because the CoT is a corallivore, meaning it feeds on coral. Thus, outbreaks have the potential to destroy entire reefs. The CoT eats the fleshy polyps of a stony coral colony leaving behind white scars of the remaining dead calcium carbonate coral skeleton. In a balanced ecosystem CoTs feed on fast-growing Acroporid coral species, however when CoT numbers are abundant they begin feeding on slow growing coral colonies like Porites, which can devastate reefs for many years into the future.

Natural predators of the adult CoT include titon triggerfish (Balistoides viridescens), white-spotted pufferfish (Arothron hispidus), napoleon wrasse, humphead wrasse (Cheilinus undulates), giant triton snails (Charonia tritonis) and painted shrimp (Hymenocera picta). Overfishing of these predators, particularly the Giant Triton, valued for its large, beautiful shell, may have led to increased CoT outbreaks. Furthermore, it is possible that our wastewater and fertilizer have also contributed to these outbreaks. Scientists theorize that nutrient-rich runoff into the ocean from human activities has enabled more CoT larvae to survive, because CoT larvae feed on planktonic algae and an increase in nutrients favors excessive algal growth. Thus more nutrients –> more algal –> more CoTs –> greater damage to coral reefs.

Methods of CoT control:

  • Land Disposal
    • Collect CoTs, handling them with large serving tongs. Bring them to land and bury them.
    • When stressed CoTs will attempt to spawn, therefore it is essential to remove them from the water as quickly as possible.
  • Cutting up and Crushing in situ
  • Tying in bags in water
  • Poison Injection (acetic acid or sodium bisulfate)
    • Injection causes the CoT to disintegrate
  • Using dead CoTs as material for compost has been practiced in Fiji

Currently, we are exploring these methods at my site and will be developing a removal program in the future!