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Station 5:
Cirial Beach


From the Visitor Center contemplate El Cirial Beach and its reef. This is a good place for a group photo.

visitas isla iguana
playa el cirial

Coastline areas and their inhabitants

The coast is divided into three zones. The LITORAL OR INTERTIDAL ZONE extends between the limits of high and low tides; the SUBLITORAL ZONE is always submerged; and the SUPRALITORAL ZONE begins at the high tide line. Each zone is inhabited by different organisms.

In the lower area of the beach, away from the bohío, it is common to find  Polychaete worms . They live in tubes made from their saliva, sand, and shells. At high tide they display feathers with which they filter plankton to feed.

Cangrejo fantasma

Ghost Crabs are the color of sand and very fast, making them difficult to see. They feed on algae that they extract from the sand, creating  pellets that decorate the beach, forming extravagant designs.

gost crab
tides isla iguana
Cangrejo hermitaño

The crabs  Hermits or Kikirikakiri feed on carrion and everything they find on the beach. They use the shells generated by molluscs and as they grow they must change shells.

With the new moon in March, a massive migration to the shore to spawn is observed.

Unlike adults, their larvae can breathe underwater and integrate with plankton. The survivors return to the beaches. This allows them to colonize distant places by being  transported  by ocean currents as part of the plankton.


The Concholi is very  common  on beaches, palm groves and fruit trees, where they look for food such as carrion, fruits and coconuts, they even climb trees and palm trees.

cangrejo isla iguana

The white sands of Isla Iguana are the product of coral erosion by various methods.

1. Animals that feed on coral, known as bioeroders.

Drums and Trigger Fish ingest and evacuate whole fragments of candles ( Pocillopora spp.)

Arothron meleagris

Arothron meleagris.  

Above: Its painted phase is called Tamboril Tigre.

Below: Its yellow phase is called Pez Guineo.

pez gatillo

The Blue Triggerfish ( Pseudobalistes  naufragium ) lives at the base of the reef where it makes beautifully patterned nests in the sand.

Its name "Trigger" is the product of a pronounced spine at the base of its head that it unfolds to avoid being swallowed by a predator, by getting stuck in its throat.

Parrotfish scrape massive coral colonies to digest the polyp and evacuate coral sand.

pez loro

The Bicolor Parrot ( Scarus rubroviolaceous ) inhabits the deep waters of coral communities.

parrot fish
pes coralivoro

Bluebeard Parrot ( Scarus ghobban ).

Above: Blue phase.

Bottom: Striped phase.

coral pizza

Common Porous Fungus ( Porites  lobata ) exhibiting scrapes made by parrotfish.

2. Animals that feed on algae and  They scrape the surface of the coral.

Sea urchins feed on algae, scraping the surface of the coral, creating sand and keeping the surface clean to make it easier for coral larvae to attach and grow. 


The Black Hedgehog (Headband  mexicanum) is the most common on Iguana Island. It produces very painful punctures that can become infected because the spines fragment within the skin.

sea urchin

The Orange Hedgehog ( Lytechinius panamensis )  It is a rare species that produces dangerous punctures because its toxin is very strong and  I might  kill a person  allergic .


The Elegant Hedgehog decorates itself with fragments of algae, shells and corals to avoid predators.

Surgeonfish frequent the reef in large schools to feed on algae attached to the coral, keeping the surface clean and evacuating coral sand.

Its name "Surgeon" is the product of a spine on either side of the base of its tail fin that is as sharp as a scalpel and unfolds to defend itself against predators.

peces isla iguana
surgeon fish

The Convicted Surgeon ( Acanthurus  triastegus ) frequents the reef lagoon in large schools and the easiest to see  together  to El Cirial beach.

pez cirujano
peces isla iguana

The Blue Surgeonfish ( Acanthurus xanthopterus ) prefers deeper water and is found along the slope at all dive sites.

Above: Blue variety.

Bottom: black variety.

The Damsels defend their algae cultures on the coral like beasts, even from fish larger than them. When feeding, they scrape the surface creating sand.


Indigo Damsel ( Stegastes acapulcoensis )

damesel fish
pez isla iguana

Blue-Gold Damsel ( Stegastes flavilatus ). Above: juvenile. Bottom: adult keeping an eye on his algae culture.

jaqueta gigante
castañuela gigante

The Giant Castanet ( Microspathodon dorsalis ) is the largest of the Damselfish. Above: juvenile. Bottom: adult.

3. The  Fragments of coral that are detached from the reef by the waves and especially tidal waves, accumulate on the coastline and roll by the action of the waves until they are pulverized.

Historical observations allow us to affirm that strong climatic events, which generate  large  swells, whether due to bad weather or background tides, which originate in the center of the Pacific Ocean, destroy sections of the coral communities that surround the island, generating millions of fragments that are thrown ashore by the strong waves.

The following figure shows in the center, an aerial photo of the island from 2003,  Note that in the places indicated by the numbers, where the coastline was rocky, after the bottom tides of 2016, coralline gravel beaches were generated. They are not sand yet, they are fragments of coral torn from the bottom by the waves. 

grava coral
playas isla iguana


Diaz Villani, Marco Lisandro. 2005. Isla Iguana Wildlife Refuge: Field Guide. Illustrations by María Gabriella Díaz de Restrepo and Juan Sucre. 2a  Edison. Panama: Post Depot Press. 70 pages. 593.6 D542.

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