Holothuria mexicana
Encyclopedia
Holothuria mexicana, also known as the Donkey Dung sea cucumber
is commonly found in the Caribbean
. It is a commercially important aspidochirote (sediment feeding) sea cucumber that can reach a total length of 50 cm (20 in).
. Populations are unimodal and have a 1:1 male to female sex ratio.
.
It is a shallow or demersal water species most commonly found between 2 m (7 ft) to 10 m (33 ft) depth and up to 20 m (66 ft) depth. It inhabits sandy bottoms with calm waters including seagrass
beds, offshore reef
s or mangroves.
, specifically consuming organic matter such as algae, tiny aquatic organisms and waste materials. Metals, such as copper, nickel, lead and zinc associated with coastal pollution, can bioaccumulate within H. mexicana tissues. Therefore, this species has been suggested as a biological indicator for these metals.
, Panama
and Venezuela
.
Natural parasites
on H. mexicana are bacteria
, protozoa
ns and metazoans. The metazoans that commonly feed on these sea cucumbers are turbellarians, gastropods, copepod
s, crab
s and fish
es.
Holothuria mexicana spawns throughout the year but has peak spawning periods that varies with geography, which may linked to temperature. Spawning occurs from May to July in Panama
, August to September in Florida
, and September to October in Curaçao
.
During spawning, females forcefully expel all their eggs into the water in a single burst from their gonopore
(the opening where gametes are released). Both males and females sometimes wave their tentacles around during spawning which may aid in fertilization by mixing the sperm and eggs. After fertilization, eggs develop into non-feeding auricular larvae develop in ~64 hours.
where it is considered an important health food. The ease to catch sea cucumbers, high commercial value and slow recruitment rates have led to global declines in sea cucumber populations and fisheries on less commercially valuable species.
There are fisheries for H. mexicana in Panama, Nicaragua and Venezuela. In Panama, the species has a low economic value due to its tough and rigid texture but is fished because of decline of other commercial sea cucumbers. In 1997, 25 fishers took part in a 30 day fishing period where over 750 000 sea cucumbers of three species (H. mexicana, Isostichopus badionotus
, Astichopus multifidus) were caught. Sea cucumber fishing is now banned in Panama but illegal fishing has been reported. Holothuria mexicana have small population sizes and were in high risk of collapse in the area if the same level of fishing had continued.
In Venezuela, the sea cucumber fishery began in 1991-1992 but was shut down by 1995 due to poor fisheries regulation. Illegal fishing continued, however, as 500 kg of H. mexicana worth 150 000 USD was confiscated in the Archipelago Los Roques National Park in 1996. In 2005, China had reported that 0.5 tonnes of sea cucumber were imported from Venezuela.
Sea cucumber
Sea cucumbers are echinoderms from the class Holothuroidea.They are marine animals with a leathery skin and an elongated body containing a single, branched gonad. Sea cucumbers are found on the sea floor worldwide. There are a number of holothurian species and genera, many of which are targeted...
is commonly found in the Caribbean
Caribbean
The Caribbean is a crescent-shaped group of islands more than 2,000 miles long separating the Gulf of Mexico and the Caribbean Sea, to the west and south, from the Atlantic Ocean, to the east and north...
. It is a commercially important aspidochirote (sediment feeding) sea cucumber that can reach a total length of 50 cm (20 in).
Description
This sea cucumber is transversely wrinkled and reaches 50 cm (20 in) in total length. It has a top surface that is dull brown or grey with occasional warts. The bottom surface is reddish, orange or pale and is uniformly covered in tube feetTube feet
Tube feet are the many small tubular projections found most famously on the oral face of a sea star's arms, but are characteristic of the water vascular system of the echinoderm phylum which also includes sea urchins, sand dollars and sea cucumbers and many other sea creatures.Tube feet function in...
. Populations are unimodal and have a 1:1 male to female sex ratio.
Distribution and habitat
This species is found throughout the Caribbean and reaches southern BrazilBrazil
Brazil , officially the Federative Republic of Brazil , is the largest country in South America. It is the world's fifth largest country, both by geographical area and by population with over 192 million people...
.
It is a shallow or demersal water species most commonly found between 2 m (7 ft) to 10 m (33 ft) depth and up to 20 m (66 ft) depth. It inhabits sandy bottoms with calm waters including seagrass
Seagrass
Seagrasses are flowering plants from one of four plant families , all in the order Alismatales , which grow in marine, fully saline environments.-Ecology:...
beds, offshore reef
Reef
In nautical terminology, a reef is a rock, sandbar, or other feature lying beneath the surface of the water ....
s or mangroves.
Diet
Holothuria mexicana feeds on sediments at the bottom of the Atlantic OceanAtlantic Ocean
The Atlantic Ocean is the second-largest of the world's oceanic divisions. With a total area of about , it covers approximately 20% of the Earth's surface and about 26% of its water surface area...
, specifically consuming organic matter such as algae, tiny aquatic organisms and waste materials. Metals, such as copper, nickel, lead and zinc associated with coastal pollution, can bioaccumulate within H. mexicana tissues. Therefore, this species has been suggested as a biological indicator for these metals.
Predation
Holothuria mexicana is a food source for people, and is actively caught for consumption off the shores of NicaraguaNicaragua
Nicaragua is the largest country in the Central American American isthmus, bordered by Honduras to the north and Costa Rica to the south. The country is situated between 11 and 14 degrees north of the Equator in the Northern Hemisphere, which places it entirely within the tropics. The Pacific Ocean...
, Panama
Panama
Panama , officially the Republic of Panama , is the southernmost country of Central America. Situated on the isthmus connecting North and South America, it is bordered by Costa Rica to the northwest, Colombia to the southeast, the Caribbean Sea to the north and the Pacific Ocean to the south. The...
and Venezuela
Venezuela
Venezuela , officially called the Bolivarian Republic of Venezuela , is a tropical country on the northern coast of South America. It borders Colombia to the west, Guyana to the east, and Brazil to the south...
.
Natural parasites
Parasitism
Parasitism is a type of symbiotic relationship between organisms of different species where one organism, the parasite, benefits at the expense of the other, the host. Traditionally parasite referred to organisms with lifestages that needed more than one host . These are now called macroparasites...
on H. mexicana are bacteria
Bacteria
Bacteria are a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals...
, protozoa
Protozoa
Protozoa are a diverse group of single-cells eukaryotic organisms, many of which are motile. Throughout history, protozoa have been defined as single-cell protists with animal-like behavior, e.g., movement...
ns and metazoans. The metazoans that commonly feed on these sea cucumbers are turbellarians, gastropods, copepod
Copepod
Copepods are a group of small crustaceans found in the sea and nearly every freshwater habitat. Some species are planktonic , some are benthic , and some continental species may live in limno-terrestrial habitats and other wet terrestrial places, such as swamps, under leaf fall in wet forests,...
s, crab
Crab
True crabs are decapod crustaceans of the infraorder Brachyura, which typically have a very short projecting "tail" , or where the reduced abdomen is entirely hidden under the thorax...
s and fish
Fish
Fish are a paraphyletic group of organisms that consist of all gill-bearing aquatic vertebrate animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish, as well as various extinct related groups...
es.
Reproduction
Minimum size at sexual maturity is between 13 cm (5 in) to 20 cm (8 in) total length and 150 g (5 oz) gutted weight, though smaller sexually mature individuals have been found.Holothuria mexicana spawns throughout the year but has peak spawning periods that varies with geography, which may linked to temperature. Spawning occurs from May to July in Panama
Panama
Panama , officially the Republic of Panama , is the southernmost country of Central America. Situated on the isthmus connecting North and South America, it is bordered by Costa Rica to the northwest, Colombia to the southeast, the Caribbean Sea to the north and the Pacific Ocean to the south. The...
, August to September in Florida
Florida
Florida is a state in the southeastern United States, located on the nation's Atlantic and Gulf coasts. It is bordered to the west by the Gulf of Mexico, to the north by Alabama and Georgia and to the east by the Atlantic Ocean. With a population of 18,801,310 as measured by the 2010 census, it...
, and September to October in Curaçao
Curaçao
Curaçao is an island in the southern Caribbean Sea, off the Venezuelan coast. The Country of Curaçao , which includes the main island plus the small, uninhabited island of Klein Curaçao , is a constituent country of the Kingdom of the Netherlands...
.
During spawning, females forcefully expel all their eggs into the water in a single burst from their gonopore
Gonopore
A gonopore, sometimes called a gonadopore, is a genital pore in many invertebrates. Hexapods, including insects have a single common gonopore, except mayflies, which have a pair of gonopores...
(the opening where gametes are released). Both males and females sometimes wave their tentacles around during spawning which may aid in fertilization by mixing the sperm and eggs. After fertilization, eggs develop into non-feeding auricular larvae develop in ~64 hours.
Fishery
Sea cucumbers are fished by snorkelling or hookah diving for human consumption. Although some species are fished for local consumption, most species are exported to ChinaChina
Chinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture...
where it is considered an important health food. The ease to catch sea cucumbers, high commercial value and slow recruitment rates have led to global declines in sea cucumber populations and fisheries on less commercially valuable species.
There are fisheries for H. mexicana in Panama, Nicaragua and Venezuela. In Panama, the species has a low economic value due to its tough and rigid texture but is fished because of decline of other commercial sea cucumbers. In 1997, 25 fishers took part in a 30 day fishing period where over 750 000 sea cucumbers of three species (H. mexicana, Isostichopus badionotus
Isostichopus badionotus
Isostichopus badionotus, also known as the chocolate chip cucumber or the cookie dough sea cucumber, is a sea cucumber common in the western Atlantic Ocean.It is a large species that grows to a length of 45 centimeters...
, Astichopus multifidus) were caught. Sea cucumber fishing is now banned in Panama but illegal fishing has been reported. Holothuria mexicana have small population sizes and were in high risk of collapse in the area if the same level of fishing had continued.
In Venezuela, the sea cucumber fishery began in 1991-1992 but was shut down by 1995 due to poor fisheries regulation. Illegal fishing continued, however, as 500 kg of H. mexicana worth 150 000 USD was confiscated in the Archipelago Los Roques National Park in 1996. In 2005, China had reported that 0.5 tonnes of sea cucumber were imported from Venezuela.