Featured Research

from universities, journals, and other organizations

Coral Reef Fish Harbor An Unexpectedly High Biodiversity Of Parasites

Date:
September 13, 2007
Source:
Institut de Recherche Pour le Développement
Summary:
A grouper fish found off New Caledonia was found to be parasitized by 12 species of microscopic monogenean worms. This diversity of parasites has just been confirmed also in the malabar grouper, 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.

Coral reefs of warm seas are among the richest ecosystems of the world in terms of their biodiversity.
Credit: iStockphoto

IRD researchers  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 "Systématique, Adaptation, Évolution" (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, "mère 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 island's 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.


Story Source:

The above story is based on materials provided by Institut de Recherche Pour le Développement. Note: Materials may be edited for content and length.


Cite This Page:

Institut de Recherche Pour le Développement. "Coral Reef Fish Harbor An Unexpectedly High Biodiversity Of Parasites." ScienceDaily. ScienceDaily, 13 September 2007. <www.sciencedaily.com/releases/2007/09/070905123839.htm>.
Institut de Recherche Pour le Développement. (2007, September 13). Coral Reef Fish Harbor An Unexpectedly High Biodiversity Of Parasites. ScienceDaily. Retrieved July 23, 2014 from www.sciencedaily.com/releases/2007/09/070905123839.htm
Institut de Recherche Pour le Développement. "Coral Reef Fish Harbor An Unexpectedly High Biodiversity Of Parasites." ScienceDaily. www.sciencedaily.com/releases/2007/09/070905123839.htm (accessed July 23, 2014).

Share This




More Plants & Animals News

Wednesday, July 23, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Michigan Plant's Goal: Flower and Die

Michigan Plant's Goal: Flower and Die

AP (July 22, 2014) — An 80-year-old agave plant, which is blooming for the first and only time at a University of Michigan conservatory, will die when it's done (July 22) Video provided by AP
Powered by NewsLook.com
San Diego Zoo Welcomes New, Rare Rhino Calf

San Diego Zoo Welcomes New, Rare Rhino Calf

Reuters - US Online Video (July 21, 2014) — An endangered black rhino baby is the newest resident at the San Diego Zoo. Sasha Salama reports. Video provided by Reuters
Powered by NewsLook.com
Shark Sightings a Big Catch for Cape Tourism

Shark Sightings a Big Catch for Cape Tourism

AP (July 21, 2014) — A rise in shark sightings along the shores of Chatham, Massachusetts is driving a surge of eager vacationers to the beach town looking to catch a glimpse of a great white. (July 21) Video provided by AP
Powered by NewsLook.com
$23.6 Billion Awarded To Widow In Smoking Lawsuit

$23.6 Billion Awarded To Widow In Smoking Lawsuit

Newsy (July 20, 2014) — Cynthia Robinson claims R.J. Reynolds Tobacco Company hid the health and addiction risks of its products, leading to the death of her husband in 1996. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins