Coral Reef Survey for Aitutaki, Cook Islands, 2008

Occurrence Observation
Dernière version Publié par Southwestern Pacific Ocean Biogeographic Information System (OBIS) Node le janv. 28, 2025 Southwestern Pacific Ocean Biogeographic Information System (OBIS) Node
Date de publication:
28 janvier 2025
Licence:
CC-BY 4.0

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Description

Natural disturbances such as crown-of-thorns starfish outbreaks and coral bleaching in recent years have played a major role in shaping the reefs of Aitutaki today. Although, anthropogenic disturbances may play a major role as well, this remains difficult to comprehend due to lack of a consistent reef monitoring program on Aitutaki. The purpose of this study is to examine the current state of Aitutaki’s reef as well as re-establish its monitoring program. Based on information provided by this survey, the reefs of Aitutaki may have recovered subsequent to the disturbance in the 1990s, however these were patchy possibly a result of the different environmental regimes experienced at each site. Coral cover range from 34% (at Pacific RC) to 8% (at Pacific RI), and size classes were predominantly in the 8-16 cm class (~8-10 year-old colonies) particularly at the more pristine reefs (Pacific RC and Airport). This suggests that these reefs recruited immediately after the COTS outbreak in the ‘90s. The high cover of crustose coralline algae (CCA) at Atuatane suggests that Aitutaki’s reefs are still in the early stages of recovery. However, high CCA cover can hinder the growth and survival of newly settled corals, which may be the case on Aitutaki. The larger colonies only recorded at Maina in the 64-128 cm class suggested that the location of this site or possibly the establishment as a Marine Protected Area (MPA or raui) may have provided a refuge (in terms of being remote) for corals and other marine life. Anthropogenic disturbances as well as COTS at Maina may be minimal. Low coral cover and high turf algae (TA) noted at Atuatane (I) and Tokai’i as well as small coral colony sizes due to die-backs suggested that these sites are experiencing poor conditions for coral growth and survival. The 2005 National Environment Service survey of Manuae proposed the possibility of Manuae being a source population for Aitutaki based on observed ocean currents at the time. Information obtained from NOAA’S Oceanwatch website on ocean surface currents around these islands also supports this possibility. Assuming that Manuae is a source population for Aitutaki, a decline in marine resources on Manuae may affect the recovery of Aitutaki’s reefs.

Enregistrements de données

Les données de cette ressource occurrence 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 191 enregistrements.

Cet IPT archive les données et sert donc de dépôt de données. Les données et métadonnées de la ressource sont disponibles pour téléchargement dans la section téléchargements. Le tableau des versions liste les autres versions de chaque ressource rendues disponibles de façon publique et permet de tracer les modifications apportées à la ressource au fil du temps.

Versions

Le tableau ci-dessous n'affiche que les versions publiées de la ressource accessibles publiquement.

Comment citer

Les chercheurs doivent citer cette ressource comme suit:

Rongo T (2025). Coral Reef Survey for Aitutaki, Cook Islands, 2008. Version 1.0. Southwestern Pacific Ocean Biogeographic Information System (OBIS) Node. Occurrence dataset. https://nzobisipt.niwa.co.nz/resource?r=aitutaki_coral_2008&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 : 48c1ac93-7fd2-412d-9650-d6ae8d773f55.  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

Occurrence; Observation

Contacts

Teino Rongo
  • Fournisseur Des Métadonnées ●
  • Créateur ●
  • Personne De Contact
Florida Tech
Avarua
CK

Couverture géographique

Aitutaki, Cook Islands

Enveloppe géographique Sud Ouest [-18,957, -159,845], Nord Est [-18,821, -159,724]

Couverture temporelle

Date de début / Date de fin 2008-06-01 / 2008-06-30

Méthodes d'échantillonnage

Four 50-m transects (replicates) were deployed for all fore reef sites. Transects were placed following the reef contour at a depth of 7 m parallel to shore and laid consecutively at intervals of 10 m for Atuatane. For the remaining three sites, transects were stacked due to the frequent interruption of the reef by channels. Four 50-m transects were also deployed for all lagoon sites. Transects were deployed following the reef contour at depths ranging from 1 to 1.5 m laid consecutively at intervals of 10 m with the exception of Atuatane, which was laid at intervals of 10 m or more due to the patchiness of the reef at this site.

Etendue de l'étude The survey focused on the northwestern side of Aitutaki, an area most likely impacted by land-based development. Three sites were established within the lagoon: Maina (control site; also an MPA), Tokai’i (non-MPA), and Atuatane (adjacent to the newly established landfill). Four fore reef sites were established: Atuatane (directly offshore from the Atuatane lagoon site), Pacific RC (control site; northern side of major channel in the Pacific Resort area), Pacific RI (impact site; southern side of channel), and Airport site located at the western end of the runway where a proposed development is expected.

Description des étapes de la méthode:

  1. Point Intercept (PI) and coral colony size was used to examine benthic communities. A two-meter belt transect (1 m on each side) was used for quantifying macro-invertebrates (i.e., sea urchins, sea cucumbers, Tridacna spp., Trochus spp., and COTS) at all sites. All species were recorded and identified to the lowest taxonomic level possible (i.e. genus and species). Species identification was verified using Randall and Myers (1983) and Veron (2000).
  2. Point Intercept (PI) Method. A 1-m2 quadrat frame was tossed every 5 m along a 50-m transect for a total of 10 quadrats. The quadrat is lined with strings equally spaced dividing the quadrat into 25 sections providing 16 points where the strings intercept. Any substratum falling under each intercept was recorded and it's percent cover calculated. Substrates included categories of corals, soft corals, algae (i.e., turf, crustose coralline, and macro), and other abiotic substratum (i.e., sand and pavement).

Citations bibliographiques

  1. Rongo, T., 2008. Coral reef survey for Aitutaki. Report for the Cook Islands National Environment Service. 32pp.

Métadonnées additionnelles

marine, harvested by iOBIS

Remerciements Thanks to Environment Officer Vavia Puapii and boatman Rimaroa Tuiravakai for their assistance in data collection. Thanks also to Environment Officer Bobby Bishop for coordinating survey logistics on Aitutaki. Special thanks to Jackie Rongo for discussions and editorial assistance throughout the preparation of the report.
Introduction Aitutaki is located at 18º 52’ S and 159º 46’ W, about 260 km north of Rarotonga. The area of the mainland of this almost-atoll island is about 16 km2 with a moderate-sized lagoon lined by 15 small islands (motu) around its perimeter. This predominantly sandy lagoon with numerous micro-atolls host a range of marine organisms, making it one of the most beautiful lagoons in the world that provides many benefits to the people of Aitutaki. These benefits include food resources, recreational activities, and eco-tourism. The increase in development over the last twenty years to meet the demand of the tourism industry along with natural disturbances (e.g., global warming, crown-of-thorns starfish or COTS outbreaks, and hurricanes) pose a threat to the existence of this delicate ecosystem. However, this is not limited to Aitutaki; similar effects are evident on other coral reefs around the world.
Objet The purpose of this survey is to examine the state of Aitutaki’s reef as well as collect baseline information for future comparisons. During the 1990’s, the reef of Aitutaki went through several natural disturbances: a bleaching event in the early ‘90s followed by a COTS outbreak degraded the reef to its current state. With any monitoring program, it is of foremost interest to distinguish natural and anthropogenic disturbances on reefs as management approaches differ accordingly. Although, the Ministry of Marine Resources (MMR) has conducted coral surveys in the past, their focus has been on quantifying exploitable resources rather than utilizing these resources as bio-indicators for assessing environmental impacts, using methodologies that are not comparable to this survey
Identifiants alternatifs https://nzobisipt.niwa.co.nz/resource?r=aitutaki_coral_2008