Division of Aquatic Resources

By Mia Melamed Tierney, Kaua‘i Monitoring Technician

Slivers of sun peeked between the clouds illuminating the depths below the morning wind-swept kai. We backrolled off the boat, my eyes tracked silver-scaled bodies as they scattered with our descent. We reached the reef’s edge adjacent to a sloping seafloor fading into a deep blue haze. Today I joined Dr. Eric Brown, a coral reef ecologist with the National Park Service, who has been studying marine benthic community trends in Hanalei Bay since 2003. Our mission this morning was to return to four permanent sites (Figure 1) to re-install coral settlement tiles (Figure 2), approximately one week before the start of summer spawning. Three months later we will retrieve the plates to be analyzed for coral larvae recruitment. The extant coral colonies in the bay have adapted to endure extreme winter swell, heavy freshwater inundation, sedimentation, and high turbidity, in addition to whatever debris or pollutants are carried off the land.

Figure 1. Map of Hanalei Bay. Blue circles show where the coral settlement tiles are placed. Five arrays are placed at each site. See Figure 2 for an example of a single array. Makahoa and Puʻu Pōā are classified as ”outside” the bay. The Wall and Waipā are ”inside” the bay. Site selection has been based on surveys by Friedlander et al. (1997).

Figure 2. Dr. Eric Brown securing the terracotta plates onto PVC pipe which are slid onto rebar. Hanalei, Kauaʻi. May 29, 2024.

According to Dr. Brown, Hanalei Bay has some of the highest coral recruitment rates when he compared his data to North Molokaʻi and to other regions around the world (Friedlander and Brown, 2006). It is important to note that recruitment is not a measure or proxy of survival rate. Coral reefs are a foundational component, playing an instrumental role in the productivity across ecosystems, from the outer reef to their upstream counterparts. As with many places, there is immeasurable value that connects ʻohana with the resources above and below, throughout the Hanalei ahupuaʻa.

The Division of Aquatic Resources is honored to assist with the ongoing collaboration between state, federal, and non-profit partners, demonstrating the importance of establishing and maintaining a relationship to produce meaningful work. Long-term monitoring of coral reef demography is one piece that fits into a larger puzzle. To make well-informed decisions long-term datasets are paramount. It is DAR’s kuleana to gather place-based information that will help shed light on any trends of a particular marine resource and to share these findings with the community. It is a part of DAR’s mission to put the community’s interests and concerns at the forefront. If your community has a concern regarding a marine natural resource, please reach out to your local office. If the resource is under our jurisdiction, we can assess the situation and help determine the next steps. A special mention goes to the Hanalei Watershed Hui, their aloha and support have made this work possible.

References:
Friedlander, A.M., and J.D. Parrish. 1997. Fisheries harvest and standing stock in a Hawaiian Bay. Fish. Res. 32(1): 33-50
Friedlander, A. M., & Brown, E. K. (2006). Hanalei Bay, Kauai marine benthic communities since 1992: spatial and and temporal trends in a dynamic Hawaiian coral reef ecosystem.