*2.1. Study Site and Sampling*

The northeastern coast of Trinidad has undefined patch reefs, and a fringing reef (see [12]). Beaches within close vicinity of these reefs are largely defined as sandy, stony, or rocky. The tropical climate has two distinct seasons, with a dry period from January to mid-June and a rainy period that extends the remainder of the year (June–December). Tides are semidiurnal with maximum high tides reaching 2 m (meters) in open water, and extreme low tides can reach 0.2 m.

Study sites in accessible areas along the northeastern coast are located at Salybia Bay (SB) (located between 10◦50.097 N, 60◦55.208 W and 10◦50.100 N, 60◦55.157 W), which is part of the only fringing reef in Trinidad. This system has been an important site for citizen/volunteer coral reef monitoring focused on cnidarian and invertebrate abundances and distributions, because it is very shallow during spring low tides (~0.2 m) and the intertidal zone extends some 200 m parallel to the shoreline. This fringing reef is affected by sediment discharge from local rivers throughout the year, specifically during the rainy period from June to December.

Pequelle Bay (PB), located to the east of SB (between 10◦50.111 N, 60◦55.129 W and 10◦50.181 N, 60◦54.954 W), has a mixture of rocks and tide pools along the intertidal zone. During spring low tides, this part of the reef becomes fully exposed for a 3-h period until tides return. Patchy undeveloped reefs are present at Grande L Anse (GA), also known as Toco Bay (between 10◦50.107 N, 60◦56.772 W and 10◦50.266 N, 60◦56.674 W), which has a mixture of rocky outcrops. This study site has a mixture of sand, stony and rocky

beaches with village homes within close vicinity. Spring low tides revealed a rocky patch reef with scattered tide pools interspersed throughout the intertidal zone.

Volunteers marked the study area with GPS points, and quantified an area of 500 m<sup>2</sup> using a 50-m open reel fiberglass measuring tape during extreme low tides (<0.3 m). Each transect was placed within a 500 m<sup>2</sup> study area, and a total area of 1500 m2 was examined at each site. The Line Intercept Transect (LIT) method [9] was used to examine only the lower intertidal areas at SB, PB, and GA. Transect positions within each 500 m<sup>2</sup> area were marked using a global positioning system (GPS). A 50 m open reel fiberglass measuring tape was placed parallel to the shoreline in each area, and benthic components were recorded at every 0.5 m interval on the measuring tape. Benthic components, such as reef-building corals, zoantharians, macroalgae, coral rubble, and other invertebrates, such as sea urchins, fireworms, and sea cucumbers were recorded if they touched the 0.5 m intervals along the measuring tape. This was repeated three times within each 500 m<sup>2</sup> study area, and for a total of 3 study areas. Water temperature and salinity were measured using a YSI Pro 1030 probe at three random points along each 50 m LIT. Percentage cnidarian and benthic cover was calculated for benthic communities.
