galapagos-reef-revival

Pilot Coral Nursery Study

About this repository

Data, code, figures, tables, and supporting material for the first assessment of coral growth, survival, and condition in a pilot Pocillopora nursery in the Galápagos Islands.

This repository supports the study:

Dávalos, N., Velasco-Cedeño, D., & Brandt, M. (2026). First assessment of the physiological performance of nursery corals in the Galápagos Islands: seasonal impacts on Pocillopora (Scleractinia: Pocilloporidae) growth. Revista de Biología Tropical, 74(S1), e202610168. https://doi.org/10.15517/0xznfj40

• A brief guide to the code used in this research can be found here.

Repository structure

The repository can be organized as follows:

galapagos-reef-revival/
├── README.md                         # General overview of Galápagos Reef Revival
│
└── 2022-23-pilot-study/
    ├── README.md                     # information and reproducibility for this paper
    │
    ├── Code/                         # Data processing and analysis scripts
    │
    ├── Data/
    │   ├── Raw/                      # Original datasets
    │   └── Processed/                # Cleaned and analysis-ready datasets
    │
    └── Results/                      # Figures and main and supplementary tables generated from the analyses

Our study

Coral communities in the Galápagos Islands experience strong seasonal and interannual environmental variability. This study evaluated how seasonal thermal conditions influenced the performance of nursery-grown Pocillopora corals in Puerto Villamil Bay, Isabela Island, Galápagos.

The study combined:

• a baseline survey of coral communities in Puerto Villamil Bay;
• cultivation of 12 Pocillopora morphotypes in two rope nurseries;
• photographic measurements of coral fragment growth;
• monthly assessments of mortality and coral condition;
• high-frequency in situ seawater temperature records; and
• El Niño 1+2 sea-surface temperature anomalies from NOAA.

The pilot nursery was established in January 2022 with 191 coral fragments. Fragment size was evaluated in January 2022, June 2022, and January 2023, allowing growth to be compared between the warm (January-May 2022) and cold (June-December 2022) seasons. Coral condition monitoring included the percentage of dead tissue, bleached tissue, and algal cover.

Main findings

• Pocillopora represented 73.6% of the 3,569 hermatypic coral colonies recorded during the baseline survey.
• Nursery temperatures ranged from 18.71 to 30.15 °C during persistent La Niña conditions.
• Mean coral planar area increased from 6.40 ± 2.51 cm² in January 2022 to 27.75 ± 15.85 cm² in January 2023.
• Overall survival in the nursery was 80%.
• Relative and specific growth rates were higher during the warm season, whereas absolute planar-area growth was slightly higher during the cold season.
• The cold season was associated with higher mortality, tissue loss, and algal overgrowth, with substantial variation among morphotypes.
• Coral gardening is feasible in Galápagos, but nursery and restoration planning should account for seasonality and differences among donor colonies/morphotypes.

Data

The repository is intended to contain the datasets used to reproduce the analyses reported in the paper.

Dataset	Coverage	Description
Coral baseline survey	Nov-Dec 2021	Location, identity, size, and health condition of coral colonies surveyed in Puerto Villamil Bay
Nursery growth	Jan 2022-Jan 2023	Fragment identity, morphotype, planar area, maximum length, and derived growth metrics
Coral condition	May-Dec 2022	Mortality and estimates of dead tissue, bleaching, and algal cover
In situ temperature	Jan-Dec 2022	HOBO TidbiT temperature records collected at the nursery site at 10-min intervals
ENSO conditions	2022-early 2023	Weekly El Niño 1+2 SST anomalies obtained from the NOAA Climate Prediction Center

The coral-condition percentages are derived from categorical field scores following Goergen et al. (2020), using the upper limit of each percentage interval as described in the paper.

License & Citation

The code in this repository is licensed under the MIT License. The data are licensed under the Creative Commons Attribution 4.0 International (CC BY 4.0) License.

If you use material from this repository, please cite the associated publication:

Dávalos, N., Velasco-Cedeño, D., & Brandt, M. (2026). First assessment of the physiological performance of nursery corals in the Galápagos Islands: seasonal impacts on Pocillopora (Scleractinia: Pocilloporidae) growth. Revista de Biología Tropical, 74(S1), e202610168. https://doi.org/10.15517/0xznfj40