Tropical Eastern Pacific

The Tropical Eastern Pacific is one of the twelve marine realms that cover the shallow oceans of the world. The Tropical Eastern Pacific extends along the Pacific Coast of the Americas, from the southern tip of the Baja California Peninsula in the north to northern Peru in the south. It also includes a number of islands and island groups, including the Galápagos, Revillagigedo, Cocos and Clipperton.

The WWF and Nature Conservancy divide the Tropical Eastern Pacific realm into two marine provinces, Tropical East Pacific and Galápagos, which are further subdivided into marine ecoregions.


  • Tropical East Pacific Marine Province
  • Galápagos Marine Province
    • Northern Galápagos Islands
    • Eastern Galápagos Islands
    • Western Galápagos Islands


  • Spalding, Mark D., Helen E. Fox, Gerald R. Allen, Nick Davidson et al. "Marine Ecoregions of the World: A Bioregionalization of Coastal and Shelf Areas". Bioscience Vol. 57 No. 7, July/August 2007, pp. 573–583. [1]
Cardisoma crassum

Cardisoma crassum, known as the mouthless crab, is a species of terrestrial crab found in the coastal tropical eastern Pacific from Baja California to Peru. It has a purplish-blue shell, red legs and white main pincer. Cardisoma crassum is common among mangrove roots, where it builds its burrow. It also occasionally occurs on the driest part of the channel banks and flats".

El Niño–Southern Oscillation

El Niño–Southern Oscillation (ENSO) is an irregularly periodic variation in winds and sea surface temperatures over the tropical eastern Pacific Ocean, affecting the climate of much of the tropics and subtropics. The warming phase of the sea temperature is known as El Niño and the cooling phase as La Niña. The Southern Oscillation is the accompanying atmospheric component, coupled with the sea temperature change: El Niño is accompanied by high air surface pressure in the tropical western Pacific and La Niña with low air surface pressure there. The two periods last several months each and typically occur every few years with varying intensity per period.The two phases relate to the Walker circulation, which was discovered by Gilbert Walker during the early twentieth century. The Walker circulation is caused by the pressure gradient force that results from a High-pressure area over the eastern Pacific Ocean, and a low-pressure system over Indonesia. Weakening or reversal of the Walker circulation decreases or eliminates the upwelling of cold deep sea water, thus creating an El Niño by causing the ocean surface to reach above average temperatures. An especially strong Walker circulation causes a La Niña, resulting in cooler ocean temperatures due to increased upwelling.

Mechanisms that cause the oscillation remain under study. The extremes of this climate pattern's oscillations cause extreme weather (such as floods and droughts) in many regions of the world. Developing countries dependent upon agriculture and fishing, particularly those bordering the Pacific Ocean, are the most affected.

Galapagos bullhead shark

The Galapagos bullhead shark, Heterodontus quoyi, is a bullhead shark of the family Heterodontidae found in the tropical eastern Pacific Ocean between latitudes 0° to 10°S, at depths between 3 and 40 m. It can reach a length of 1.07 m.

The reproduction of this bullhead shark is oviparous.


The Indo-Pacific, sometimes known as the Indo-West Pacific or Indo-Pacific Asia, is a biogeographic region of Earth's seas, comprising the tropical waters of the Indian Ocean, the western and central Pacific Ocean, and the seas connecting the two in the general area of Indonesia. It does not include the temperate and polar regions of the Indian and Pacific oceans, nor the Tropical Eastern Pacific, along the Pacific coast of the Americas, which is also a distinct marine realm.

The term is especially useful in marine biology, ichthyology, and similar fields, since many marine habitats are continuously connected from Madagascar to Japan and Oceania, and a number of species occur over that range, but are not found in the Atlantic Ocean.

The region has an exceptionally high species richness, including 3000 species of fish, compared with around 1200 in the next richest marine region, the Western Atlantic, and around 500 species of reef building corals, compared with about 50 species in the Western Atlantic.


Linantha is a genus of crown jellyfish in the family Linuchidae. It is a monotypic genus and the only species is Linantha lunulata which was first described by the German biologist Ernst Haeckel in 1880. It is found in the tropical eastern Pacific Ocean in the vicinity of the Galápagos Islands.

List of marine ecoregions

The following is a list of marine ecoregions, as defined by the WWF and The Nature Conservancy

The WWF/Nature Conservancy scheme groups the individual ecoregions into 12 marine realms, which represent the broad latitudinal divisions of polar, temperate, and tropical seas, with subdivisions based on ocean basins. The marine realms are subdivided into 62 marine provinces, which include one or more of the 232 marine ecoregions.

The WWF/Nature Conservancy scheme currently encompasses only coastal and continental shelf areas; ecoregions of the deep oceans have not yet been delineated.


Littoraria is a genus of sea snails, marine gastropod mollusks in the family Littorinidae, the winkles or periwinkles.There are more than fifty species in this genus of which more than 20 species are believed to be synonyms of Littoraria scabra, a very variable species.Many of the species in this genus occur in the Indo-West Pacific region and in the Tropical Eastern Pacific, where they are found in large numbers on the trunks, trees and prop roots of tropical mangrove forests a few metres above high tide level. These snails feed on the thin film of algae, epiphytes, fungi, diatoms and leaf epidermis of these mangroves. The species living on higher levels of the trees have thinner shells, and are more variable in shell colour.

Within this genus, Littoraria aberrans is the only ovoviviparous species with an intracapsular metamorphosis.


A megadrought (or mega-drought) is a prolonged drought lasting two decades or longer. Past megadroughts have been associated with persistent multiyear La Niña conditions (cooler than normal water temperatures in the tropical eastern Pacific Ocean).The term megadrought is generally used to describe the length of a drought, and not its acute intensity. In scientific literature the term is used to describe decades-long droughts or multi-decadal droughts. Multiyear droughts of less than a decade, such as the Dust Bowl drought of the 1930s, are generally not described as megadroughts even though they are of a long duration. In popular literature multiyear or even single year droughts are occasionally described as megadroughts based upon their severity, the economic damage they inflict or other criteria, but this is the exception and not the rule.

Phantom cardinalfish

Lachneratus phasmaticus, also known as the phantom cardinalfish, is a species of fish in the family Apogonidae, the cardinalfishes. It is the only member of its genus. It is native to the tropical eastern Pacific and Indian Oceans. This fish can be found in crevices and underwater caves, and it occurs at depths of 3 to 104 m. It grows to a standard length of 7.4 cm (2.9 in).This species was discovered when "an unusual cardinalfish was taken in a trawl off of Hawaii" around 1969. It was later collected off of Fiji. It was described to science in 1991 and placed in a new genus. The name of the genus honors the American ichthyologist Ernest A. Lachner (1916-1996), who was curator emeritus at the United States National Museum in recognition of his contributions to the systematics of the Indo-Pacific cardinalfishes.

Pocillopora inflata

Pocillopora inflata is a species of stony coral in the family Pocilloporidae. It was first described by Peter William Glynn in 1999. It is found growing on coral reefs in the tropical eastern Pacific Ocean but is nowhere abundant.


Pyroteuthis is a genus of squid in the family Pyroteuthidae. It is differentiated from the genus Pterygioteuthis by size, head shape and behaviour. Species within the genus are separated by the arrangement of tentacular photophores; the shape of the hectocotylus, and the shape of the hectocotylus hooks. With the exception of the Tropical Eastern Pacific, the genus is circumpolar in tropical and temperate oceans. The species P. addolux is the only member to occur in the North Pacific.

Semicossyphus darwini

Semicossyphus darwini is a species of ray-finned fish native to the tropical eastern Pacific Ocean. Common names include the Chilean sheepshead wrasse, the goldspot sheepshead or the Galapagos sheepshead wrasse.

Sharptooth smooth-hound

The sharptooth smooth-hound (Mustelus dorsalis) is a houndshark of the family Triakidae. It is found on the continental shelves of the tropical eastern Pacific from southern Mexico to Peru between latitudes 20°N and 5°S. Its length is up to 64 cm.

The sharptooth smooth-hound dwells on the bottom, feeding on crustaceans, particularly shrimp. Reproduction is viviparous, with four pups per litter, and length at birth about 21 cm.

Stegastes flavilatus

Stegastes flavilatus, commonly known as beaubrummel, is a damselfish of the family Pomacentridae. It is native to the tropical eastern Pacific Ocean, its range extends from Mexico, Baja California and the Gulf of California southwards to the Galapagos Islands and mainland Ecuador. It is found on rocky inshore reefs at depths ranging from 1 to 10 m (3 ft 3 in to 32 ft 10 in).

Stegastes leucorus

Stegastes leucorus, commonly known as the whitetail damselfish, the whitetail gregory or the whitetail major, is a damselfish of the family Pomacentridae. It is native to the tropical eastern Pacific Ocean.

Stegastes rectifraenum

Stegastes rectifraenum, commonly known as the Cortez damselfish or Cortez gregory, is a damselfish of the family Pomacentridae. It is native to the tropical eastern Pacific Ocean, its range including Baja California in Mexico, and the Gulf of California. It is found on rocky inshore reefs at depths ranging from 1 to 10 m (3 ft 3 in to 32 ft 10 in).


Tehuantepecer, or Tehuano wind, is a violent mountain-gap wind traveling through Chivela Pass, most common between October and February, with a summer minimum in July. It originates from eastern Mexico and the Bay of Campeche as a post-frontal northerly wind, accelerated southward by cold air damming, which crosses the isthmus and blows through the gap between the Mexican and Guatemalan mountains. The term dates back to at least 1929. This wind can reach gale, storm, and hurricane force. The leading edge of its outflow (or cold front) may form rope cloud over the Gulf of Tehuantepec. These winds can be observed on satellite pictures such as scatterometer wind measurements, they influence waves which then propagate as swell and are sometimes observed 1,600 km (1,000 mi) away (such as in the Galapagos Islands). These strong winds bring cooler sub-surface waters to the surface of the tropical eastern Pacific Ocean and may last from a few hours to 6 days.

Temperate Northern Pacific

The Temperate Northern Pacific is a biogeographic region of the Earth's seas, comprising the temperate waters of the northern Pacific Ocean.

The Temperate Northern Pacific connects, via the Bering Sea, to the Arctic marine realm, which includes the polar waters of the Arctic Sea. To the south, it transitions to the tropical marine realms of the Pacific, including the Tropical Eastern Pacific along the Pacific coast of the Americas, the Eastern Indo-Pacific in the central Pacific Ocean, and the Central Indo-Pacific of the western Pacific basin. The Taiwan Strait forms the boundary between the Temperate Northern Pacific and the Central Indo-Pacific.

Characteristic fauna include the Pacific salmon and trout (Oncorhynchus spp.), gray whale (Eschrichtius robustus), and North Pacific right whale (Eubalaena japonica).

Tripneustes depressus

Tripneustes depressus, the white sea urchin or sea egg, is a species of sea urchin in the family Toxopneustidae. It is found on the seabed in the tropical eastern Pacific Ocean including Mexico, Panama, Ecuador and the Galápagos Islands.

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