Marine Biology

Rakahanga, Cook Islands

The Rakahanga project aims to restore native giant clam populations to the lagoon in three phases. Phase I involves engaging potential stakeholders and establishing consensus for the project scope, implementation, expected outcomes and benefits. A draft schedule and logistical requirements will also be specified, along with baseline ecological conditions against which expected results will be measured. Phase II involves setting up a culture facility on Rakahanga to support on-going stock reintroduction, which includes collecting clam broodstock, initiating spawning, and rearing juveniles for re-introduction. Training hatchery personnel and documenting relevant processes and procedures will also occur during Phase II. Phase III involves physically re-introducing clams to lagoon habitats, and quantifying success by survival, location, and environmental conditions over time.

Enhancing AMRC’s Hatchery Productivity

The Aitutaki Marine Research Centre (AMRC) is chartered with restoring native populations of functionally extinct giant clams to the Aitutaki lagoon. In addition to supporting routine hatchery operations, I have conducted a series of experiments to enhance productivity that facilitates population recovery. For example, to increase larval survival, I manipulated broodstock diets for 5 weeks prior to spawning. The results included larger egg sizes (conducive to survival in nutrient-limited conditions), and increased volumes of lipids critical to early larval development. In a second experiment involving newly hatched larva, I supplemented culture water with elevated levels of amino acids for 24 hours post-fertilization. The combination of enhanced conditions increased larval survival from less than 1% to almost 6%.

Biodiversity Study, Santa Monica Bay

After several years of anthropogenic abuse, Santa Monica Bay is slowly beginning to recover. Although pollution remains a seminal issue, I undertook and independent field study to determine whether littoral biodiversity increased as distances from point pollution increased. To do so, I took photos of replicate pier pilings at three piers in the Bay and counted for species richness and diversity. The Shannon and Simpson diversity indices revealed that diversity and richness indeed increased as distance from source pollution increased. Although the validity of these indices has recently been challenged, the experience proved useful in subsequent enquiries, particularly with respect to experimental design, and data collection and analyses in the context of conservation biology.