Dataset: Bocas del Toro 2021 sea urchin and coral recruit monitoring from August to September 2021 (Coral microbiome resilience project)

Ecological surveys were conducted in the Bahía Almirante region of Bocas del Toro, Panama, during August and September 2021. The Bahía Almirante is a semi-enclosed lagoon that has experienced widespread ecological degradation from anthropogenic stressors such as eutrophication, tourism development, overfishing, and hypoxia, making it an ideal system for monitoring the resilience of coral reef communities under high levels of environmental stress.

Ten sites within the Bahía were selected for monitoring due to their previously documented responses to hypoxia. Surveys were performed on shallow coral reefs at three depths characterized by distinct coral and benthic community compositions: 10, 20, and 40 ft (3, 6, and 12 m). All data were collected visually in situ on SCUBA by four observers familiar with coral and benthic reef surveys.

Both coral recruits and urchin species were counted at ten sites within fixed 50 × 50 cm quadrats placed along a 50 m transect at each of the three depths. Coral recruit counts provide insight into coral recovery and continued input of new individuals into a population. Coral recruits were defined as corals less than 4 cm in diameter, unless visibly dying or receding, and were counted by observers within 30 × 30 cm portions of the fixed 50 × 50 cm quadrats. Coral recruits were identified to genus, as visible identification to species at small sizes is not feasible.

Urchins were simultaneously monitored because they can be highly abundant at some sites and depths in Bocas del Toro and are important grazers that can also drive high levels of bioerosion. In addition, urchins can have density-dependent effects on coral recruitment. All urchins, including Echinometra viridis and Diadema antillarum, within 50 × 50 cm quadrats were counted and identified non-destructively by the same observers.