PELD - ABRS | Avaliação e monitoramento dos recifes de Abrolhos

Study Extent

Monitored sites include five reefs in the Abrolhos Archipelago, a set of small volcanic islands ~55 km off the coast and within the Marine National Park. Data has been acquired since 2006, mostly during the Austral summer.

Sampling

We used fixed photo-quadrats demarcated with metal pins that are periodically replaced. Each benthic sampling unit is composed of a mosaic of 15 high resolution photos and covering ~70 cm2. Each sampling site has 10 sampling units. During the period monitored, some years and/or locations were not sampled due to logistical and funding constrains. Images were annotated semi-automatically with the deep neural network provided by the CoralNet platform*. Relative cover was estimated from the identification of benthic organisms below 30 random points distributed in each image (one photo-quadrat = a mosaic of 15 high resolution close-up images). Organisms were identified at nine broad taxonomic or functional groups and categorized either as slower-growing longer-lived reef builders [corals, crustose calcareous algae (CCA) and hydrocorals] or their faster-growing shorter-lived antagonists [(frondose macroalgae, turf, benthic cyanobacteria mats (BCM), zoanthids, sponges and “other organisms” (OO)]. * Beijbom O, Edmunds PJ, Roelfsema C, Smith J, Kline DI, Neal BP, et al. Towards automated annotation of benthic survey images: variability of human experts and operational modes of automation. PLoSOne. 2015; 10(7): e0130312. https://doi.org/10.1371/journal.pone.0130312 PMID: 26154157

Quality Control

We used an 80% confidence threshold (label accuracy: 95.4%, functional group accuracy: 96.9%, fraction above threshold: 53%) for the semi-automatic annotation carried out with the deep neural network of the CoralNet platform.

Method steps

1. Benthic sampling is described in Teixeira et al. (2021).

Coral reefs organisms were identified at the lower taxa possible (species or genus)

1. Agaricia
   rank: genus
2. Favia gravida
   rank: species
3. Madracis decactis
   rank: species
4. Meandrina braziliensis
   rank: species
5. Millepora
   rank: genus
6. Millepora nitida
   rank: species
7. Montastrea cavernosa
   rank: species
8. Mussismilia braziliensis
   rank: species
9. Mussismilia hartti
   rank: species
10. Mussismilia hispida
    rank: species
11. Mussismilia leptophylla
    rank: species
12. Porites
    rank: genus
13. Scolymia wellsi
    rank: species
14. Siderastrea
    rank: genus

Zoanthids includes Palythoa caribaeorum and Zoanthus spp.

1. Zoantharia
   rank: order

Crustose Calcareous Algae (CCA)

1. CCA
   rank: unranked

Benthic cyanobacteria mats

1. Cyanobacteria
   rank: phylum

Includes all encrusting sponges

1. Encrusting sponge
   rank: unranked

Includes all species of macroalgae

1. Macroalgae
   rank: unranked

Includes all massive sponges

1. Massive sponge
   rank: unranked

Includes octocorals, bryozoans, ascidians, polychaetes, anemones

1. Other organisms
   rank: unranked

Includes all boring sponges

1. Perforating sponge
   rank: unranked

Includes sediment and dead organisms

1. Substrate/Dead
   rank: unranked

Turf

1. Turf
   rank: unranked

Data sampled in Abrolhos Marine National Park, Bahia, Brazil