Wildlife of Mauritius

The wildlife of Mauritius is composed of its flora and fauna. Mauritius is located in the Indian Ocean to the east of Madagascar. Due to its isolation, it has a relatively low diversity of wildlife; however, a high proportion of these are endemic species occurring nowhere else in the world. Many of these are now threatened with extinction because of human activities including habitat destruction and the introduction of non-native species. Some have already become extinct, most famously the dodo which disappeared in the 17th century.

Fauna

Primates at Black River, Mauritius

Mammals

Due to its isolated geographic location, remote from large land masses, Mauritius has no terrestrial mammals. The only mammals that made their way to the island are bats and marine mammals.

Of the 2 fruit bats, only one remains - the black-spined Flying fox. Two insectivorous microbats also remain.

A number of mammals have been introduced either accidentally or intentionally, including rats, mice, tenrecs, mongooses, rusa deer and crab-eating macaques as well as domestic ruminants and pigs.

These introduced mammals have had a varied impact on the island's pristine fauna. Given that they were free from natural predators, they very rapidly grew to large numbers and were soon predating and competing with the local fauna.

Birds

Pink pigeon (Columba mayeri)
( Mauritius Fodi)

Over 100 species of bird have been recorded in Mauritius. There are seven or eight surviving endemic species on the main island depending on taxonomy. The Mauritius grey white-eye is the most common of these, being widespread across the island including in man-made habitats. The others are less common and are mainly restricted to the Black River Gorges National Park in the south-west of the island. The Mauritius kestrel, Mauritius parakeet and pink pigeon all came close to extinction but are now increasing thanks to intensive conservation efforts.

Rodrigues Island has two further endemic species, the Rodrigues warbler and Rodrigues fody. Seabird colonies are present on many of the smaller islands of the country.

A wide variety of birds have been introduced into Mauritius. These include some of the most common and conspicuous birds of the islands including the common myna, Madagascar fody, red-whiskered bulbul and zebra dove. The common myna is becoming a pest due to its well documented habit of displacing smaller bird species from their habitat and also destroying the smaller bird species young. The mynas were introduced for commercial reasons, primarily to help control the locusts which eat the sugar cane leafage, instead, they prey on small indigenous lizards which are easier to catch due to their basking habits which is required for their metabolism, the lizards have become the mynas primary source of food, but due to the myna's preying on these lizards an imbalance is being created with insects which the lizard would prey on which the common myna doesn't eat due to its inability to crawl under rocks and forage in the dense grass, flora, and fauna.

Reptiles

A number of endemic reptiles are found in Mauritius, particularly on Round Island. These include day geckos (Phelsuma), night geckos (Nactus), skinks and the keel-scaled boa. Giant tortoises formerly inhabited the island but are now extinct, although the Seychellois species has been introduced to the Pamplemousses gardens.

(Phelsuma Ornata)

Freshwater Fauna

In the 1950s, guppies locally known as millions abounded in Mauritian rivers. These little fish, often found in brackish water, appear to be outnumbered nowadays by swordtails, introduced in the 60’s. Bigger fish like the carp and the gourami have also dwindled after the introduction of the tilapia in the 1950s. A popular freshwater fish used to be the damecéré, (known as carpe de Maillard in French) introduced by Monsieur Céré, an administrator of Pamplemousses garden during the French period. These silver tinted fish were common in ponds and lakes in the 50’s but are now rarely seen. They were often offered for sale at the Port-Louis Central Market and by street vendors.

Recently the berri rouge has been introduced in view of supplementing the diet of the local population in protein. These fish are related to the tilapia but are somewhat rosy coloured. They are mostly bred on aquaculture farms. The catfish is also a new comer, and has most probably been dumped into local waters by aquarists. These fish are proving to be a nuisance and are disturbing the ecosystem of Mauritian rivers.[1]

All the above fishes have been introduced. Indigenous fishes are few, and one of them is the goby, locally known as the cabot. They are extremely voracious fishes and have been observed to swallow fishes almost their size! The adults are found mostly near estuaries while the younger fish prefer the lower course of rivers. Seldom active, they lie in wait to pounce on an unsuspecting prey. Gobies go to lay their eggs in the sea, and the larvae swim upstream around December. Locally known as bichiques, they are caught and eaten as a delicacy by the local population. But their numbers seem to have considerably dwindled. (There is another theory that gobies do not go to the sea but that their eggs are swept into the ocean by water currents; the larvae swim upstream in great numbers during the new moon.)

A fish that can live both in sea and fresh water is the milkfish. Known locally as loubine, it is found in fairly great numbers near estuaries at particular times of the year. These young fish are often caught and eaten fried. However, this practice should be discouraged because these fish can grow very fast to adults weighing over 25 kg.[2] En passant, this is perhaps the fish that the Dutch saw when they first landed in Mauritius in 1598. As reported by historians: 'they saw many fish in the streams around the coast, and some large birds which dived after the fish and ate them.'[3]

The mullet also lives in shoals near estuaries but go up rivers in search of food. It is sometimes caught by fishermen on river banks who use bread as bait. However, it is a notoriously difficult fish to catch.

An easier game for the freshwater fisherman is perhaps the lune argentée, which can also be fished along rivers, notably the Grand River North West.

Another indigenous dweller of Mauritian rivers and lakes is the eel. But it is not very often seen and prefers to stay in crevices or hide under rocks. Eels spend most of their time in fresh water but go back to the sea, where they come from, to reproduce. Mauritian eels, like those from Madagascar, Réunion, Seychelles and East Africa, have their breeding grounds in the Nazareth Trough, an ocean trench situated between longitudes 60-65 E and latitudes 10-20 S. Eels can wriggle across land, and this perhaps explains why eels are found in some isolated ponds of Mauritius. There are three varieties of eels on the island. Two of them are found in Madagascar, Reunion and Africa, while the third one is present in the Seychelles. Most probably, the commonest eel is the marbled eel. Eels can grow quite big, if they cannot find a way to go back to the sea.[4] This perhaps explains why some very big eels have been caught in Mauritius, notably at La Ferme reservoir. In Rodrigues an eel of more than 2 metres long was caught in a spring, in the heart of a forest, at Cascade-Pigeon.[5] It is believed that the eel was 100 years old! There is a theory that eels play an important role in eco-systems; they prevent springs from drying up. All three Mauritian species take a silvery colour when they go back to the sea.

Shrimps are common on the banks of most rivers. There are about six varieties of shrimps, and some of them are endemic. One type of shrimp is the chevrette grand bras. This shrimp has a transparent body speckled with tiny reddish-brown or black spots. The female, smaller than the male, has two pincers of equal length but of a thinner size. Another type is the crevette chevaquine. It prefers to live near estuaries.

Crayfish on river bed

Crayfish are also found in many rivers, especially those that are swift running and well oxygenated. A crayfish, locally known as the bétangue, is endemic to Mauritius. It is easily recognized by its pincers, one being much bigger than the other. It is of a brownish-orange colour and can reach a size of 10 cm. It has nocturnal habits and is becoming very rare. Another variety is the chevrette sonz. It is of a smaller size and has thin pincers. A third variety is the camaron. It is light-blue and the male is longer than the female, although the latter is of a bigger girth. Its size can sometimes exceed 30 cm (pincers included). After hatching, the larvae of most crayfish go to live in the sea, and swim back to the river when they reach adult stage. This migration is often done against fast moving currents, and crayfish have been observed to climb waterfalls by clinging on rocks.

Fresh water crabs are often found in waterways close to the sea. During the reproductive period, the adults gather on some riverbanks near the coast. The eggs are swept into the sea by water currents, and on hatching the young are carried into the river or coastal pond by the tides. The crabs feed mostly on algae and other vegetable matter.

Soft shell terrapins with long necks have been noticed in some rivers. They are of Chinese origin and were apparently introduced in a river of the Moka district about a century ago; these reptiles are considered to be aggressive and are fast invading other rivers of the island.[6]

Marine Life

Butterflies

About 39 butterfly species are known from Mauritius and Rodrigues. 7 of these are endemic.

Molluscs

Main articles: List of non-marine molluscs of Mauritius and List of marine molluscs of Mauritius

Flora

Lantana camara

About 670 native species of flowering plant are found in Mauritius and nearly half of these are endemic. Rainforest formerly covered most of the island with palm savannah in drier regions and areas of heathland in the mountains. Most of this natural vegetation has been destroyed and what remains is threatened by the spread of introduced plants.

The national flower of Mauritius is Trochetia boutoniana or "boucle d'oreille" which is now restricted to a single mountain. Native trees include the Mauritius ebony (Diospyros tesselaria), takamaka (Calophyllum tacamahaca) and various palms. Introduced plants that have become invasive include "Chinese" (actually Brazilian) guava (Psidium littorale) and Lantana camara. Bougainvillea (Bougainvillea glabra) and frangipani (Plumeria alba) are among the most commonly planted ornamental species.

Conservation

Black River Gorges National Park

Conservation work in Mauritius is carried out by the National Parks and Conservation Service (NPCS) and by non-governmental organizations such as the Mauritian Wildlife Foundation (MWF) and Durrell Wildlife Conservation Trust (DWCT).

The Black River Gorges National Park covers 65.74 km² of land and another 45 km² is protected by nature reserves such as Round Island and Île aux Aigrettes.

Efforts to preserve native flora and fauna have included captive breeding, habitat restoration and the eradication of introduced species.

References

  1. ↑ Le poisson-chat, un dangereux prédateur qui envahit les rivières, L'Express, 25 March 2013
  2. ↑ Sea-fishes of Mauritius, Michael Atchia
  3. ↑ A short history of Mauritius, P.J. Barnwell & A. Toussaint
  4. ↑ The eel, Knowledge, Volume X, p. 1828
  5. ↑ L'anguille centenaire attire les foules, L'Express, 18 March 2009.
  6. ↑ Gare à l'invasion des tortues à trompe, L'Express, 16 January 2013

Further reading