288
P.W.Glynn
Pocilloporid fringing reefs are present at Cafio Island (Guzman and Cortes
1989) and a few fringing reefs, with significant structural contributions
from pocilloporid and poritid corals, occur in the innermost reaches of
Golfito (Fig. 19.1, site 6; Figs. 19.2F, 19.3). The Golfito reefs have sparse live
coral cover, a result of heavy siltation stress due to forest clearing and
various sorts of other damage (e.g. mining and road construction) to the
surrounding watershed. Numerous fringing and patch pocilloporid reefs
occur in the Gulf of Chiriqui (Fig. 19.4A,B), particularly on the sheltered
sides of islands. A coral reef on the south side of Bahia de las Damas, Coiba
Island, covering about 160 ha, is the largest known reef adjacent to the
eastern Pacific mainland (Fig. 19.1, site 7). In the upwelling area of the
Pearl Islands, Gulf of Panama (Fig. 19.1, site 8; Fig. 19.2E), most of the small
pocilloporid reefs are located on the N or E sides of islands, away from the
full effect of cool, upwelling currents. Farther to the south, along the Choc6
coast of Colombia near Utria (Fig. 19.1, site 9), remarkably there are a few
coral reefs present in this area in spite of exceptionally high annual rainfall
(7-8 m) and voluminous river discharge with high sediment loading. Like
Golfito, the fringing reefs of the Colombian Choc6 reveal extensive dead
coral cover, presumably also due to relatively recent stresses resulting from
poor land use practices (Vargas Angel 1996). The fringing pocilloporid
reefs on the lee (east) side of Gorgona Island (Fig. 19.1, site 10), with
moderate to high coral cover, are the best developed in Colombia and reveal relatively few anthropogenic disturbances (von Prahl et al. 1979). At
least one well-developed fringing reef occurs as far south as 1°28'S, on the
coast at Machalilla, Ecuador (Fig. 19.1, site 11). Several large (10-20m diameter) coral patches, some with 100- to ~200-year-old colonies of Pavona
clavus, occur along the leeward shore of Isla La Plata, about 30 km offshore
of Machalilla. As in Costa Rica and Panama, tracts of dead branching corals
and dead and eroded massive colonies still evident on coral reefs in
Colombia and Ecuador bear witness to the damaging effects of the
1982-1983 El Nino event.
The oceanic islands of the eastern Pacific, the Revillagigedo Islands,
Clipperton Atoll, Cocos, Malpelo and the Galapagos Islands, also support
abundant reef-building coral communities and coral reefs (Fig. 19.1). Clipperton Atoll, with dominantly massive poritid colonies covering about
370 ha, is probably the largest coral reef in the eastern Pacific. Even though
Clipperton is a well-developed atoll with high coral cover, its reef-building
coral fauna is notably depauperate, consisting of only seven species of
scleractinian corals and one species of hydro coral. Since the euphotic zone
extends deeper at the oceanic island sites, the depth distribution of zooxanthellate corals also extends to 30-60 m or slightly deeper, in contrast to
continental areas where corals are limited to 10-15m (Fig. 19.5). Malpelo
P.W.Glynn
Pocilloporid fringing reefs are present at Cafio Island (Guzman and Cortes
1989) and a few fringing reefs, with significant structural contributions
from pocilloporid and poritid corals, occur in the innermost reaches of
Golfito (Fig. 19.1, site 6; Figs. 19.2F, 19.3). The Golfito reefs have sparse live
coral cover, a result of heavy siltation stress due to forest clearing and
various sorts of other damage (e.g. mining and road construction) to the
surrounding watershed. Numerous fringing and patch pocilloporid reefs
occur in the Gulf of Chiriqui (Fig. 19.4A,B), particularly on the sheltered
sides of islands. A coral reef on the south side of Bahia de las Damas, Coiba
Island, covering about 160 ha, is the largest known reef adjacent to the
eastern Pacific mainland (Fig. 19.1, site 7). In the upwelling area of the
Pearl Islands, Gulf of Panama (Fig. 19.1, site 8; Fig. 19.2E), most of the small
pocilloporid reefs are located on the N or E sides of islands, away from the
full effect of cool, upwelling currents. Farther to the south, along the Choc6
coast of Colombia near Utria (Fig. 19.1, site 9), remarkably there are a few
coral reefs present in this area in spite of exceptionally high annual rainfall
(7-8 m) and voluminous river discharge with high sediment loading. Like
Golfito, the fringing reefs of the Colombian Choc6 reveal extensive dead
coral cover, presumably also due to relatively recent stresses resulting from
poor land use practices (Vargas Angel 1996). The fringing pocilloporid
reefs on the lee (east) side of Gorgona Island (Fig. 19.1, site 10), with
moderate to high coral cover, are the best developed in Colombia and reveal relatively few anthropogenic disturbances (von Prahl et al. 1979). At
least one well-developed fringing reef occurs as far south as 1°28'S, on the
coast at Machalilla, Ecuador (Fig. 19.1, site 11). Several large (10-20m diameter) coral patches, some with 100- to ~200-year-old colonies of Pavona
clavus, occur along the leeward shore of Isla La Plata, about 30 km offshore
of Machalilla. As in Costa Rica and Panama, tracts of dead branching corals
and dead and eroded massive colonies still evident on coral reefs in
Colombia and Ecuador bear witness to the damaging effects of the
1982-1983 El Nino event.
The oceanic islands of the eastern Pacific, the Revillagigedo Islands,
Clipperton Atoll, Cocos, Malpelo and the Galapagos Islands, also support
abundant reef-building coral communities and coral reefs (Fig. 19.1). Clipperton Atoll, with dominantly massive poritid colonies covering about
370 ha, is probably the largest coral reef in the eastern Pacific. Even though
Clipperton is a well-developed atoll with high coral cover, its reef-building
coral fauna is notably depauperate, consisting of only seven species of
scleractinian corals and one species of hydro coral. Since the euphotic zone
extends deeper at the oceanic island sites, the depth distribution of zooxanthellate corals also extends to 30-60 m or slightly deeper, in contrast to
continental areas where corals are limited to 10-15m (Fig. 19.5). Malpelo