Pasua (Tridacna maxima) size and abundance in Tongareva Lagoon, Cook Islands

Données d'échantillonnage
Dernière version Publié par Southwestern Pacific Ocean Biogeographic Information System (OBIS) Node le mai 2, 2024 Southwestern Pacific Ocean Biogeographic Information System (OBIS) Node

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Description

Pasua (Tridacna maxima), also known as pa’ua, are one of two species of giant clams native to the Cook Islands. Pasua are a culturally significant food item throughout the Cook Islands, and in the Northern Cooks remain a staple food source. Pasua are rare in the southern Cook Islands as a consequence of previous overharvesting but increasing numbers of pasua from the northern Cook Islands, especially Tongareva, are available for sale in Rarotonga. In response to declining numbers in the southern Cook Islands, a giant clam hatchery was established on Aitutaki in 1990 by the Cook Islands Ministry of Marine Resources (MMR) to help reintroduce clams to the lagoon.

The specific aims of the survey were to assess the size distribution, abundance and density of pasua in Tongareva Lagoon.

In addition, this survey aimed to provide baseline information for the Island Council regarding the establishment of specific size limits, the possible need for a rahui (harvest closure), and the ideal location of such a rahui if required.

Enregistrements de données

Les données de cette ressource données d'échantillonnage ont été publiées sous forme d'une Archive Darwin Core (Darwin Core Archive ou DwC-A), le format standard pour partager des données de biodiversité en tant qu'ensemble d'un ou plusieurs tableurs de données. Le tableur de données du cœur de standard (core) contient 27 enregistrements.

2 tableurs de données d'extension existent également. Un enregistrement d'extension fournit des informations supplémentaires sur un enregistrement du cœur de standard (core). Le nombre d'enregistrements dans chaque tableur de données d'extension est illustré ci-dessous.

Event (noyau)
27
ExtendedMeasurementOrFact 
189
Occurrence 
27

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Versions

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Comment citer

Les chercheurs doivent citer cette ressource comme suit:

Chambers C N (2024). Pasua (Tridacna maxima) size and abundance in Tongareva Lagoon, Cook Islands. Version 1.0. Southwestern Pacific Ocean Biogeographic Information System (OBIS) Node. Samplingevent dataset. https://nzobisipt.niwa.co.nz/resource?r=tongareva_clams&v=1.0

Droits

Les chercheurs doivent respecter la déclaration de droits suivante:

L’éditeur et détenteur des droits de cette ressource est Southwestern Pacific Ocean Biogeographic Information System (OBIS) Node. Ce travail est sous licence Creative Commons Attribution (CC-BY) 4.0.

Enregistrement GBIF

Cette ressource a été enregistrée sur le portail GBIF, et possède l'UUID GBIF suivante : 27b24738-02ef-4c81-b470-bfe639cd0c37.  Southwestern Pacific Ocean Biogeographic Information System (OBIS) Node publie cette ressource, et est enregistré dans le GBIF comme éditeur de données avec l'approbation du Ocean Biodiversity Information System.

Mots-clé

Samplingevent

Contacts

Charlotte N.L. Chambers
  • Fournisseur Des Métadonnées
  • Créateur
  • Personne De Contact
Researcher
Institute of Geography, The University of Edinburgh
Drummond Street
EH8 9XP Edinburgh
Scotland
GB

Couverture géographique

Tongareva Lagoon, Cook Islands

Enveloppe géographique Sud Ouest [-9,04, -158,01], Nord Est [-8,98, -157,92]

Couverture taxonomique

Pasua giant clams

Species Tridacna maxima (Pasua)

Couverture temporelle

Date de début / Date de fin 2006-05-03 / 2006-05-24

Méthodes d'échantillonnage

The survey took place over 14 days from 3–17 May 2006 with a follow-up survey at sites Te Vo, Tepetepe and between Ahuamiria and Atutahi on 24 July 2006. Fieldwork was conducted by the author, Mataora Marsters and Taimana Manata from the Tongareva Marine Research Centre (TMRC) with additional assistance from Tomas Samuela Jr., Tuku Marsters, Martin Chambers and Baar Tapu. Site selection was designed in an attempt to survey a wide cross section of the lagoon environment, for example toka (distinct coral heads), tuarai (small scattered coral heads close to shore) and kauniho (reef edges). Sites were stratified according to the section of the lagoon (e.g. far southern section) and were selected by travelling in a boat within these sections in a relatively straight line (e.g. parallel to the shore) for a set period of time (e.g. 10 minutes) until suitable habitat was encountered. From preliminary observations and based on existing biological information concerning pasua (Lewis 1987), suitable habitat was defined as toka and tuarai down to a depth of 10 metres, and kauniho, which weren’t predominately sandy.

Etendue de l'étude Tongareva Lagoon, Cook Islands

Description des étapes de la méthode:

  1. The survey area was delineated by four 50-m ropes, which were knotted to form a square. This was then placed randomly over the survey site although in the case of kauniho, the lines were placed at the edge of the kauniho extending towards the shoreline. Five transect lines were then placed within the square at 10-m intervals. All pasua found within 5 m on each side of the transect line were counted and a proportion of the total population measured. In cases where low numbers of pasua were present, every second pasua was measured but in situations where large numbers were found, measurements varied from every tenth to every one-hundreth pasua.
  2. The size distribution of pasua was evaluated by recording the length, measured in centimetres, along the shell opening (lip) using callipers. The census of pasua abundance in the lagoon was calculated by counting the number of pasua within each survey area; density was calculated as the total.

Citations bibliographiques

  1. Chambers, C. 2007. Pasua (Tridacna maxima) size and abundance in Tongareva Lagoon, Cook Islands. SPC Trochus Information Bulletin #13 – July 2007, pg. 7-12.

Métadonnées additionnelles

marine, harvested by iOBIS