Navigation Links
Coral reef fish harbor an unexpectedly high biodiversity of parasites
Date:9/5/2007

IRD researchers (1) showed that Epinephilus maculates, a fairly abundant species of grouper off New Caledonia, was parasitized by 12 species of microscopic monogenean worms. This diversity of parasites has just been confirmed also in the malabar grouper, Epinephilus malabaricus, another the coral reef species. If such a level of parasite diversity prevails in all coral-reef fish, tens of thousands of parasite species are in this ecosystem waiting to be discovered.

In the same way as the tropical rainforest, the coral reefs of warm seas are among the richest ecosystems of the world in terms of their biodiversity. In fact the best conserved areas harbour over 700 species of coral, 600 species of mollusc and nearly 4000 species of fish. These fish have been well studied by reef biodiversity specialists over the past few years, yet still little is known about their parasites. Two studies conducted by IRD researchers of Noumea have brought out evidence of this parasite species richness in two grouper species of the New Caledonian coral reef.

The new species described by the IRD taxonomists are microscopic animals less than 0.5 mm long. These tiny parasitic worms all belong to the class of monogeneans (Monogenea). They live on gills of marine fish where they find both refuge and food. Identification of each taxon is facilitated by the morphology of the genital apparatus which is characteristic for each species. In 2006, researchers from the research unit Systmatique, Adaptation, volution (UMR 148) at Noumea first studied Epinephelus maculatus, a grouper species commonly called loche grisette and quite common in the New Caledonia lagoon. Microscopic observation of nearly 800 specimens of monogeneans collected from gills of 10 individuals of this fish allowed biologists to identify 12 different species. By comparison, the Mediterranean grouper (Epinephelus marginatus) are host to just four species belonging to this class of gill parasite. At least 10 of these monogeneans found in the New Caledonian loche grisette are strictly specific: they live exclusively on this fish.

A second investigation focused on the malabar grouper (Epinephelus malabaricus, mre loche). It confirmed the diversity of monogenean gill parasites of the New Caledonian coral reef. For this second grouper species, 11 species of associated monogeneans were identified among more than 300 collected from the gills of two malabar specimens The existence of a rich fauna of monogeneans in the New Caledonia grouper was therefore confirmed. The ensuing article gives a detailed list of 44 parasite species already recorded in the malabar grouper in the whole of the Pacific Ocean.

The malabar grouper has a high initial growth rate and the adult reaches 50 kg, making it a species highly prized by aquaculture operators in South-East Asia. Young malabar groupers are taken directly from their natural habitat in order to supply the fish farms. They are subsequently fattened up quickly, as are red tuna in the Mediterranean. As an example, the Thai production of this fish thus grew from 15 000 individuals in 1991 to 265 000 in 1995. Parasite control in such breeding conditions, where high density of fish populations favours high rates of parasite infection, is crucially important, as the parasitized specimens usually have a lower than average growth rate. Better knowledge of the parasite species present in wild malabar grouper populations could help improve rearing management.

The IRD Noumea research team also substantiated the hypothesis that reef fish in general have an especially rich parasite biodiversity. The New Caledonian coral reef harbours nearly 2000 species of fish. Extrapolation of these results to the whole of this Pacific islands coral reef yielded an estimated fish parasite biodiversity of about 10 000 species. Extrapolating again, to such an aquatic ecosystem at the global scale can certainly give a figure two or three times as large.

Biologists currently have very little knowledge about the host-parasite relation that links the monogeneans to the fish. Like all parasites, they must be closely tied with their host. The specificity the newly described monogenean species have to particular groupers shows this. The disappearance of one species of fish would threfore likely lead to that of the parasites associated with it. Hosts and parasites form a system that reaches a certain equilibrium as evolution proceeds. Destruction of this equilibrium could influence the regulation of fish populations, in letting the less strongly parasitized species become more invasive, and modify the structure of coral reef communities. Maintenance of this ecosystem in a good state is already seriously threatened by global warming, pollution and the development of tourism. Therefore it is more necessary than ever to conserve the entirety of this natural habitat.


'/>"/>

Contact: Gregory Flechet
fichesactu@paris.ird.fr
33-014-803-7607
Institut de Recherche Pour le Dveloppement
Source:Eurekalert

Related biology news :

1. New Species of Coral Discovered Off Southern California
2. Tsunami-damaged coral reefs should be left to recover naturally, say scientists
3. Researchers appeal for new regulations to save coral reefs from live fish trade
4. Hidden sponges determine coral reefs nutrient cycle
5. Marine conservation organizations team up to conduct Indonesia coral reefs assessment
6. Health of coral reefs detected from orbit
7. Scientists look to the Bahamas as a model for coral reef conservation
8. Tiny polyps gorge themselves to survive coral bleaching
9. Too much sugar not good for coral reefs
10. Sea corals trick helps scientists tag proteins
11. How marine reserves are giving coral reefs a helping hand
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:6/2/2016)... YORK , June 2, 2016   The Weather ... is announcing Watson Ads, an industry-first capability in which consumers ... by being able to ask questions via voice or text ... Marketers have long sought ... the consumer, that can be personal, relevant and valuable; and ...
(Date:5/20/2016)... , May 20, 2016  VoiceIt is ... partnership with VoicePass. By working together, ... experience.  Because VoiceIt and VoicePass take slightly different ... engines increases both security and usability. ... excitement about this new partnership. "This ...
(Date:5/3/2016)... VILNIUS, Lithuania , May 3, 2016 /PRNewswire/ ... today released the MegaMatcher Automated Biometric Identification ... deployment of large-scale multi-biometric projects. MegaMatcher ABIS can ... and accuracy using any combination of fingerprint, face ... of MegaMatcher SDK and MegaMatcher ...
Breaking Biology News(10 mins):
(Date:6/27/2016)... ... June 27, 2016 , ... Cancer ... what they believe could be a new and helpful biomarker for malignant pleural ... Click here to read it now. , Biomarkers are components in the ...
(Date:6/27/2016)... ... June 27, 2016 , ... ... innovative medical technologies, services and solutions to the healthcare market. The company's primary ... various distribution, manufacturing, sales and marketing strategies that are necessary to help companies ...
(Date:6/27/2016)... -- Liquid Biotech USA , Inc. ... Research Agreement with The University of Pennsylvania ("PENN") ... patients.  The funding will be used to assess ... outcomes in cancer patients undergoing a variety of ... to support the design of a therapeutic, decision-making ...
(Date:6/24/2016)... 2016  Regular discussions on a range of subjects including ... two entities said Poloz. Speaking at a lecture ... , he pointed to the country,s inflation target, which is ... "In certain areas there ... common economic goals, why not sit down and address strategy ...
Breaking Biology Technology: