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Saving Corals: Trek and Dive Join ACIAR Coral Spawning and Restoration Initiative 2025

6/20/20253 min read

From June 11 to 15, 2025, our group joined ACIAR’s coral spawning activity in Gilutungan Island, Cebu. These five nights were more than just dives—they were full of new experiences, teamwork, and meaningful purpose. We saw how corals give life and helped protect them right in our backyard.

A Rare Opportunity

We were only allowed one tank per diver per night, so we needed to be careful with our air and plan our moves. Each dive was shallow—about 2.7 meters average, and the longest was just over 14 minutes. But every dive mattered.

Our meeting point was Cordova Port, where we boarded a small banca to Gilutungan Island. Ikuo, who had joined this same event in 2024, was assigned by ACIAR’s Dexter to help guide us. She taught us how to attach cups on the tip of cone-shaped collectors and place them on chosen coral heads already marked by buoys. We had to leave a bit of air inside the cup so the coral gametes could float up and be collected.

Step-by-Step: From Cones to Coral Counts

ACIAR had prepared three transects underwater, each with corals likely to spawn. Our group, Trek & Dive, was assigned to Transect 2. Each diver got 5 to 10 cones. When I jumped into the water and received 10 cones, I sank quickly! Good thing I inflated my BCD fast. Some teammates helped lighten the load by taking extra cones from me.

After placing cones, we returned to the boat for dinner—grilled fish, pork, soup, rice, snacks, and drinks, generously prepared by ACIAR. Around 8:00 PM, we did a second dive using red-light torches (white lights can stop corals from spawning). If we spotted gametes inside the cups, we sealed and collected them carefully.

Then came the mixing. We placed the gametes in buckets and stirred them gently to help fertilization. From each bucket, we took three 16ml samples for counting under a microscope. Perfect round ones were unfertilized, while those with odd shapes were. The counting helped estimate how many coral embryos were collected and the percentage of fertilization.

Some of us, like Keem, didn’t bring cameras to stay focused on the work. Others like Regie, Doms, and Ikuo helped document everything underwater. It was tiring, but every minute felt worth it.

Night 1 – June 11, 2025 (Wednesday)

Participants: Ikuo, Val, Cristy
Conditions: Rainy, cold evening, full moon, low tide at 6:05 PM (-0.17m)
Highlights:

  • Cones were placed underwater.

  • No spawning yet. Collected the cones after checking.

Night 2 – June 12, 2025 (Thursday, Holiday)

Participants: Ikuo, Keem, Joan, Chu, Grethel
Conditions: Calm sea, clear skies, moon 99.7%, moonrise 7:04 PM, low tide 6:42 PM (-0.20m), water 30.5°C
Highlights:

  • First coral spawning happened.

  • Less than 5 cups had gametes. Returned back to sea.

Night 3 – June 13, 2025 (Friday)

Participants: Ikuo, Val, Cristy, Joan, Regie
Conditions: Squalls, heavy rain, moon 97.9%, moonrise 7:57 PM, low tide 7:19 PM (-0.21m)
Highlights:

  • Anxious due to weather and strong rain.

  • A few cups collected and brought back.

Night 4 – June 14, 2025 (Saturday)

Participants: Ikuo, Keem, Regie, Vanessa, Doms
Conditions: Moderate rain, moon 94.1%, moonrise 8:47 PM, water 30.5°C
Highlights:

  • Deployed 98 cones.

  • 3.1 million coral embryos collected.

  • USC Dean Glenn and faculty joined.

Night 5 – June 15, 2025 (Sunday)

Participants: Ikuo, Keem, Regie, Vanessa, Doms
Conditions: Light rain, moon 88.2%, moonrise 9:34 PM, water 30°C
Highlights:

  • Almost 90 cups had gametes.

  • About 15 million coral embryos collected.

  • Helped count fertilized vs. unfertilized eggs.

Reflections from the Team

Regie: “Makaguol huna-hunaon—gagmay pa kaayo ang mga coral, unya grabe atong effort para lang mutubo sila. Apan usahay, usa lang ka sipyat nga tikang, maguba na.”

Ikuo: “Giapil nani nako sa akong schedule—kay kausa ra ni mahitabo sa usa ka tuig. Naa gani mulupad pa ug layo para lang makasuway ani. Pero para nato, naa ra ni diri sa atong duol. Bisan naa unta mi meeting sa akong amo, ni-undertime gyud ko. Dili ko gusto magmahay nga wala ko nakaapil.”

This whole activity wasn’t just about science—it was about love for the ocean, for learning, and for giving back. Maraming salamat sa ACIAR for letting us be part of this. Hanggang sa susunod na spawning season.