Giant Clam Reef Recovery
Seatrees is expanding our partnership with Ocean Gardener in Indonesia to bring a new, science-driven tool into coral restoration: giant clams.
Together, we’re translocating Tridacna maxima (the “Small Giant Clam”) from a land-based nursery in northern Bali to our Seatrees coral restoration site on Nusa Penida—helping boost coral health, reef complexity, and long-term resilience.
Why Giant Clams?
Giant clams act as ecological powerhouses on coral reefs. Their presence increases coral survival, improves water quality, and enhances overall ecosystem productivity.
Clams support coral growth by:
- Sharing symbiotic algae (zooxanthellae) that can seed surrounding corals
- Releasing nutrient-rich waste that fuels coral and algal growth
- Filtering seawater, improving clarity and reducing excess nutrients
- Creating habitat with their large, sculptural shells
- Altering water flow, enhancing micro-habitats for corals and invertebrates
As climate change accelerates reef decline, integrating species like giant clams into restoration helps increase adaptability and ecological stability—a critical priority for coral conservation.
The Clam Journey
For more than five years, Ocean Gardener and the community of Nusa Penida have stewarded thriving coral restoration sites. In 2025, founder Vincent Chalias introduced a new idea based on decades in the aquarium industry: a Giant Clam Garden to accelerate coral recovery.
In November 2025, 150 baby T. maxima clams (12 cm each) were carefully moved from the Bali nursery to their new home in Nusa Penida:
1. Nursery to Transport
Clams were placed onto custom concrete plates (five clams per plate) and secured for travel inside insulated boxes with seawater—kept cool and stable for the journey.
2. Arrival in Nusa Penida
The Ocean Gardener dive team transitioned the clams into underwater baskets fitted with mesh covers, rubber straps, ropes, and zip-ties for secure attachment to the reef.
3. Underwater Placement
Clams will remain on their plates for ~two years, growing until they reach 20–30 cm in size. Under healthy conditions, giant clams can live up to 100 years—becoming long-term contributors to reef health.
Tridacna maxima
Common name: Small Giant Clam
Range: Central Pacific to the Red Sea
Habitat: Shallow coral reefs & lagoon edges
Colors: Brilliant blues, greens, and browns
Giant clams:
- Open their mantles during the day to fuel photosynthesis
- Close in response to predators, low tide, shadows, or poor water quality
- Provide long-term structural complexity to the reef
- Host symbiotic algae that help power surrounding coral communities
Maintenance & Monitoring
Like all Seatrees projects, long-term maintenance is built into the plan.
Ocean Gardener conducts regular monitoring to manage two major coral predators:
- Drupella snails
- Crown-of-Thorns Starfish (COTS)
Quarterly predator-control data is recorded and fed into the Seatrees database to help identify regional trends and improve reef-health strategies across our coral portfolio.
Local Impact
Ocean Gardener currently employs 20 staff members, including six women:
Indah, Festi, Anastasia, Kirana, Nicole, and (add final name once confirmed).
Our partnership supports:
- Local jobs in the blue economy
- Hands-on marine conservation training
- Long-term stewardship of Nusa Penida’s reefs
Conservation Significance
This is believed to be a world-first giant-clam translocation of this kind, with Indonesian authorities celebrating the effort.
Ocean Gardener is globally recognized for restoring vibrant coral ecosystems—reviving underwater communities and transforming rubble fields into living, thriving reefs.
**Photo: Indonesian authorities at the Seatrees x Ocean Gardener giant clam delivery.
Ocean Gardener
Seatrees partners with Ocean Gardener, a local Indonesian non-profit organization with over 20 years of hands-on experience farming coral that are key to restoration and biodiversity. Their team of marine biologists, divers, and coral farmers is dedicated to restoring the degraded reefs while educating the local community on best practices to protect the reefs moving forward.