Project Title: PICSI Project 5: Life history of commercially valuable black corals in Hawaii and taxonomy of black corals in American Samoa
Project Summary

The objective of this project is twofold: (1) to characterize the growth rates and minimum size of reproductive maturity of the three commercially valuable Hawaiian black coral species (Antipathes griggi, A. grandis and Myriopathes cf. ulex) in Hawaii, and (2) to conduct a taxonomic survey of black coral populations accessible through mixed-gas technical diving off American Samoa.

Anticipated Management Application(s)  None Defined
Location(s):
  • American Samoa
Point of Contact: Office of the Point of Contact:
  • NOS PMNM
Project Title: PICSI Project 5: Life history of commercially valuable black corals in Hawaii and taxonomy of black corals in American Samoa
Methods/Approach

The objective of this project is twofold: (1) to characterize the growth rates and minimum size of reproductive maturity of the three commercially valuable Hawaiian black coral species (Antipathes griggi, A. grandis and Myriopathes cf. ulex) in Hawaii, and (2) to conduct a taxonomic survey of black coral populations accessible through mixed-gas technical diving off American Samoa.

In terms of the first objective, the proposed research project seeks to answer the following questions which are essential to the management of the Hawaiian black coral fishery: (1) What is the growth rate and does it change as colonies get larger? (2) What is the minimum size of sexual reproduction? (3) Do growth rates and minimum size of reproduction vary in colonies found at different depths (50-90 m)? Field surveys and specimen collections will be performed using trimix technical diving using closed-circuit rebreathers at depths ranging between 50-90 m off the south shore of Oahu. Black coral populations off south Oahu have already been surveyed previously as part of a related project, and include dense aggregations (1 colony/m2) of all three commercially valuable species. At these sites, black coral colonies covering a wide range of colony sizes will be tagged with a label attached to the base, and their height and width will be measured by using a tape measure underwater. Tagged colonies will be visited again within 36 months, and re-measured to determine their growth rate. Additionally, all tagged colonies will be sampled to determine their reproductive maturity. For this purpose, samples consisting of 3 cm branchlets will be clipped from the mid-section of each colony, preserved in 10% buffered formalin, and transferred to 70% ethanol after 3-5 days. Histological sections of preserved specimens will be prepared using standard histological techniques at the Histological and Imaging Core Facility located at the John A. Burns School of Medicine (JABSOM) of theUniversity ofHawaii. Sections will be viewed under light microscopy to determine whether specimens are reproductively mature.

In terms of the second objective, the proposed research seeks to understand what black coral species exist at depths accessible through mixed-gas technical diving (50-90 m) off American Samoa. Field surveys and specimen collections will be performed using trimix technical diving with the aid of closed-circuit rebreathers at depths ranging between 50-90 m. Black coral colonies will be photographed in situ and 3 cm samples collected and preserved in 10% buffered formalin. Samples will be prepared for scanning electron microscopy (SEM) (Wagner et al. 2010, 2011b) and viewed at the Biological Electron Microscope Facility (BEMF) at theUniversity ofHawaii.

 

Project Results and Management Outcomes
Project Title: PICSI Project 5: Life history of commercially valuable black corals in Hawaii and taxonomy of black corals in American Samoa
Internal References:
  •  None Defined
 
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