Hawai'i Projects

[ Home ] [ Grad Students ] [ Hawai'i Projects ] [ Am. Samoa Projects ] [ Coral ID ]

Hawai'i Research Projects

The Birkeland Lab has three ongoing research projects in Hawai'i: Amanda Meyer and Jan Dierking each have ongoing projects focusing on different aspects of the ecology and behavior of the introduced grouper, roi (Cephalopholis argus). Both of them have study sites on Oahu and the Big Island . Danielle is working on the MPA Project, a study of the effects of Marine Protected Areas on coral populations, and her study sites are also on Oahu and the Big Island. In addition, Jennifer Salerno is initiating a project in 2005 on the effects of sediment on corals, and she will be working primarily on Moloka'i.

Roi Projects: The Hawaiian Islands are the most isolated in the world, and have a unique assemblage of coral reef fish species. By comparison with most tropical Pacific localities, several fish families are underrepresented on Hawaiian reefs; among these is the family Serranidae, which includes the sea basses or groupers. The Peacock Grouper (Cephalopholis argus), or roi, is a member of the family Serranidae, and was introduced on purpose by the State of Hawai'i to Oahu and the Big Island from Moorea, French Polynesia in 1956, with the goal of creating a commercial fishery for this species. Roi quickly spread to all the main Hawaiian Islands and has become very abundant on many reefs, but the envisioned fishery never materialized after roi caused a number of Ciguatera incidents. In contrast to the benefits that roi was expected to bring to Hawai'i, many reef users now believe that roi negatively impacts native Hawaiian species. However, since little was known until recently about the movements, feeding, resource use, and basic ecology of roi in Hawai'i, with the consequence that even basic questions like “What does roi feed on?” and “How much prey does a roi individual consume?” could not be answered, it has been hard to estimate the true impact of roi in the state. Both Amanda’s and Jan’s roi projects aim at filling the current knowledge vacuum on roi in Hawai’i by studying different aspects of roi ecology and biology.

Amanda is studying the territoriality, movements, energy needs and growth rates of roi, and the potential impact of this introduced species on the native coral reef fish communities for her dissertation research. Her project consists of four components; 1) a tracking study, in which roi will be tracked and their movements and activity patterns documented, 2) an energy study, where the energy contents of prey fish are analyzed and the energy requirements of roi are quantified, 3) a growth rate study, using otoliths, and 4) a comparative study between the ecology of roi in the Hawaiian Islands and Moorea, looking at territoriality, feeding ecology and growth rates. In order to quantify the effect these fish are having on the native fish communities, it is essential to understand their territoriality, movements, energy needs and growth rates. Click here for a presentation on Amanda's research she made in October 2004. For questions or comments on Amanda's project, contact her at amandame@hawaii.edu.

Jan is focusing on the feeding ecology of roi, and on Ciguatoxin (a toxin produced by the marine dinoflagellate Gambierdiscus toxicus that can cause the neurological disease Ciguatera in humans) dynamics in this species. His study includes large scale sampling of roi populations from locations around the Big Island and Oahu using spearfishing, as well as maintaining captive roi in tanks at the Hawai'i Institute of Marine Biology (HIMB) caught live using underwater barrier nets. Jan’s study has two main research objectives. Firstly, he wants to determine the quantitative and qualitative impact of roi on native animal populations, i.e., to answer the questions “what is roi feeding on?” and “how much does it consume?” (methods used include: stomach content analysis; digestion rate experiments; energy consumption in captivity; stable isotope analysis; and data integration with roi and prey abundance information from the West Hawai'i Aquarium Project (WHAP) database). The ultimate goal of this part of the study is to produce information that would allow resource managers to decide whether or not roi impact on native species is a threat that needs to be addressed. Jan’s second objective is to determine the prevalence and concentration of ciguatoxin in roi from different locations and regions in Hawaii, in order to better understand the factors (e.g., geographic locations, roi size, or feeding preferences of roi) associated with ciguatoxicity (methods used include: monoclonal immunobead assay or “MIA”, and neuroblastoma cell assay). The ultimate goal here is to determine whether certain roi (e.g., from specific regions or of specific size) are predictably free of ciguatoxin and thus safe for consumption. Such information could allow resource managers to use a limited roi fishery as a natural way to control roi abundances. Jan’s work is currently funded by the Hawaii Coral Reef Initiative (HCRI). Click here for a presentation on Jan's research he made in August 2004 to HCRI. For questions or comments on Jan's projects, contact him at jdierkin@hawaii.edu.

MPA Project: The goal of Danielle's research project is to determine a set of ecological processes that commonly occur on coral reefs, and to then compare these processes between a range of reefs in Hawai'i. Her study sites have a range of herbivorous fish biomass and populations, which in turn reflect different levels of marine management. The purpose of this approach is to determine whether MPAs maintain coral populations and coral reefs systems in a “healthier”, more balanced state compared to unprotected areas. The ecological processes/factors she is measuring include abundance of macroalgae, crustose coralline algae, and coral populations, as well as coral juvenile survival, grazing pressure, and rates of bioerosion vs. accretion. Click here for a presentation on Danielle's research she made in August 2004 to her funding agency, the Hawai'i Coral Reef Initiative.