Realm: Marine
Climate: Tropical
Biome: Tropical Coral
Central latitude: 14.900000
Central longitude: 148.600000
Duration: 2 years, from 1984 to 2012

519 records

85 distinct species

Across the time series Amblygobius phalaena is the most frequently occurring species

Methods

Required. TThe study was carried out on the atoll of Mataiva, the western-most atoll in the Tuamotu Archipelago, French Polynesia (14°55?S, 148°36?W). This small atoll (10 km × 5 km) has an unusual morphology with a reticulated lagoon divided into approximately 70 pools (average depth: 8 m), separated by a network of slightly submerged coral reef partitions (Delesalle, 1985) (Fig. 1). In February 2012, we reassessed coral cover and fish assemblages in the same 13 pools as those surveyed in 1981 by Bell & Galzin (1984). Estimating live coral cover Bell & Galzin (1984) estimated live coral cover along a single 50 m transect along the perimeter of each study pool, at depths of 03 m. Their estimates of coral cover were qualitative, and they assigned each site to one of five coral cover categories: 0% (all dead), <2%, 2<5%, 510%, and >10%. Bell & Galzin (1984) reported that a subsequent quantitative evaluation of coral cover showed an average of 10.7% (SD = ±9%) for sites in their >10% category, providing support for their qualitative assessment. In 2012, we estimated the coral cover along three 50 m transects at each site surveyed by Bell & Galzin (1984). Transects were laid parallel to the rim of each pool at an average depth of ?1.5 m (range: 0.53 m), with as much distance as possible between transects. The total length of the reef rim around each pool varied, hence transects were separated by 530 m. Using a point-intercept method, we recorded benthic cover type every metre under the transect line (total: 51 points per transect). Benthic cover categories included: live coral (to genus; mainly Acropora, Porites, Montipora and various favid corals), macroalgae (mostly Turbinaria and Halimeda), other benthic organisms (e.g., sponges), rubble, and sand (following Lison de Loma et al., 2008). To check the accuracy of the point-intercept method, we also took a photograph of the substratum at each intercept point (total: 51 photographs per transect) on 22 of the 39 transects. The shallow depth of some parts of the transects prevented us from standardising the distance between camera and reef, hence the size of the photoquadrats varied between 100 cm2 and 625 cm2. We placed a digital grid on each photoquadrat and estimated percent live coral cover visually. We calculated average coral cover for each transect by weighting the coral cover of each photograph by the area it covered. The percent of coral cover derived from the point-intercept method was significantly correlated with the visual assessment of photoquadrats (r = 0.91, N = 22 transects, P < 0.0001). We therefore used coral cover from the point-intercept survey in subsequent analyses. Estimating fish diversity and density To estimate fish diversity and density, we faithfully replicated the method of Bell & Galzin (1984). At each site, along one of the transects laid for coral assessment, we recorded the number of each species of reef fish within 2.5 m on either side of the transect line. Data were collected once by each of two observers at a 5 min interval. We did deviate from Bell & Galzin (1984) by surveying fish on each of the other two transects laid for coral cover assessment. Each observer surveyed one of these two additional transects.

Citation(s)

@Article{BioTIME_cit398, Study_id = {651}, Citation_id = {398}, Author = {Beldade, Ricardo and Mills, Suzanne and Claudet, Joachim and Cote, Isabelle M}, Journal = {PeerJ}, Pages = {e745}, Title = {More coral, more fish? Contrasting snapshots from a remote Pacific atoll}, Volume = {3}, Year = {2015}, Doi = {10.7717/peerj.745}, Language = {English} }