Project Title: PICSI project 4: Population ecology, genetics, and modelling of Antipathes griggi in Hawaii
Project Summary

Determine the population connectivity of Antipathes griggi across small and large scales, and utilizing historical and new data to model the population demographics and distribution. 

Anticipated Management Application(s)  None Defined
  • Main Hawaiian Islands
Point of Contact: Office of the Point of Contact:
  • University of Hawaii
Project Title: PICSI project 4: Population ecology, genetics, and modelling of Antipathes griggi in Hawaii

This work will address four research components including: 1) what is the current population size structure within the Maui black coral beds and how has it changed over time, 2) what are the species and colony densities in the depths of 60-80 m in the Au‘au Channel, Maui, 3) what is the connectivity of Antipathes griggi across the Maui beds and other islands (Hawai‘i, O‘ahu, Kaua‘i, Northwestern Hawaiian Islands, and Johnston Atoll), and 4) can we predict the impacts of changes to the population through the development of a population model based on demographics and spatial distributions? 

Question one can be addressed by conducting closed-circuit mixed gas dives in the Au‘au Channel that repeat sites previously monitored.  Divers will measure colony heights and species at various depths per site.  Comparisons of colony size structure can be made across different depths, sites, or habitats.  Question two can be addressed by conducting transects to count the number of individuals within broad size categories for each species observed at depths of 60-80 m.  This is an important depth zone that remains unexplored because previous surveys have occurred only above 60 m or below 80 m.  The amount of potential black coral habitat within this zone is less than above or below, but it also serves a potential transition between varying species assemblages.  Previous work has shown that Antipathes griggi is dominant above 60 m and Antipathes grandis is dominant below 80 m (A. Montgomery, unpub.).  No quantitative surveys have been conducted in this transition zone (60-80 m) to date.  Questions one and two can be answered in the first year.

Question three can be addressed by using Restriction Digest Associated DNA Sequencing (RAD-seq) to allow comparisons of candidate genes distributed throughout the genome of Antipathes griggi.  Previous attempts of using mitochondrial and nuclear DNA (cytochrome oxidase subunit I [cox1], large subunit ribosomal RNA gene [rnl, 523 bp], and five intergenic spacers [trnW-nad2, 448 bp; nad5-nad1, 407 bp; rns-cytB, 900 bp with 122 bp non-coding; cytB-rnl, ≈210 bp – two short (≈80 bp) non-coding regions flanking tRNA Met], ITS1, ITS2, beta-actin, beta-tubulin, and calmodulin) have not been able to show sufficient variation between sites of large scale (across the Main Hawaiian Islands).  This lack of resolution in the genetic markers is believed to reflect the low variation within mitochondrial DNA and is not useful for population level variation within black corals.  With the advancing field of genomic science and the advanced RAD-seq capability of our lab, using a population genomic approach is the best way to determine population connectivity across A. griggi’s distribution within the Hawaiian Archipelago and Johnston Atoll.  Previously collected samples are available for this work.  We propose to use 30 samples each for four geographic to determine the level of connectivity to outside the Au‘au Channel,Maui and three areas within the Au‘au Channel to determine population boundaries.  This question can be addressed in years two and three.

Question four can be addressed by assembling all new and historical data and building a model that can predict the effects of changing variables on the population demographics, standing biomass, reproductive potential, and other life history characteristics.  We propose to combine a species distribution model with a population model to test the interactions of changing demographics and connectivity with disparate colony distributions both within and outside the Au‘au Channel.  This question can be address in year 3 although this can partially be worked on prior to year three.

Project Results and Management Outcomes  None Defined
Project Title: PICSI project 4: Population ecology, genetics, and modelling of Antipathes griggi in Hawaii
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