Featured Research

from universities, journals, and other organizations

New Invasive Fish Spreads Through The Ebro Delta

Date:
January 20, 2009
Source:
Plataforma SINC
Summary:
Biologists have researched and described for the first time in Europe the spread of the invasive dojo loach (Misgurnus anguillicaudatus) fish species. The fish comes from East Asia and was first discovered in the Ebro delta in 2001. Since then, it has occupied various parts of the river during its lightning spread, and is now definitively established. The researchers do not rule out that it could occupy new areas within coming years and threaten the survival of native species.

Dojo loach (Misgurnus anguillicaudatus).
Credit: Miguel Clavero

A Spanish research team has researched and described for the first time in Europe the spread of the invasive dojo loach (Misgurnus anguillicaudatus) fish species. The fish comes from East Asia and was first discovered in the Ebro delta in 2001. Since then, it has occupied various parts of the river during its lightning spread, and is now definitively established. The researchers do not rule out that it could occupy new areas within coming years and threaten the survival of native species.

The spread of the dojo loach (Misgurnus anguillicaudatus) or weather loach, as this oriental fish from the same family as the colmilleja (Cobitis Paludica) of Spain and Portugal is commonly known, contrasts starkly with the decline of native fish in the rivers and wetlands throughout the Iberian Peninsula, where 80% of species are threatened. The introduction of species from different areas is one of the most serious threats to the preservation of biodiversity, as explained in this study published in the latest issue of Biological Invasions.

“Aquatic ecosystems on the continent are the most seriously affected by invasive species, with fish populations being particularly devastated,” Miguel Clavero, the report’s lead author and researcher at the Forest Technology Centre of Catalonia, tells SINC. Nowadays, the majority of river basins throughout the Iberian Peninsula contain more foreign species than native ones.

The dojo loach is a small yellowish fish measuring around 20cm, which was first discovered in 2001 in the S่quia Mare, a channel draining the rice fields of the Ebro delta, located on the northern hemidelta (left side of the river), although individuals were also seen in the river itself. Within a few years, the dojo loach has come to occupy most of the hemidelta and has moved towards the southern part, where it was first found in 2005.

Clavero explains that “today, the species occupies a minimum of 31 1x1km UTM quadrants within the interior of the delta, and several thousand individuals have been caught during operations to monitor ichtyofauna carried out by the Ebro Delta National Park”. There is a high probability of the species expanding towards new areas. In fact, the researchers say that in the spring of 2007 the dojo loach was detected in the basin of the River Onyar, which is a tributary of the River Ter, in an area very close to the urban centre of Girona.

Salinity is a barrier

Despite its rapid expansion, Clavero and his team have shown that the distribution of the dojo loach “seems to be limited by salinity”, as it only occupies waters with a low salt concentration. This is one of the reasons why the fish has not invaded lagoons, swamps and other natural wetland areas in the delta.

“The presence of the dojo loach, like that of many other invasive fish species in the Ebro delta, is linked to the continuous flow of river water channelled from the Azud de Xerta reservoir to irrigate the rice fields, which cover 60% of the surface area of the delta,” the researcher points out.

Introduction of species is a threat

The researchers believe that the dojo loach population first appeared in the Ebro delta “after some individuals escaped from tropical fish maintenance and distribution facilities”. Centres that breed and maintain exotic fish pose a serious danger and are “an epicentre of the biological invasion process”.

This fish could be responsible for parasitic platelminths becoming established in the area, and could indirectly compete for resources with native species. “Each addition of a new species to an ecosystem has an impact on its other inhabitants which, in the case of fish at any rate, are always negative,” stresses the scientist. In the lower part of the Ebro, the presence of the dojo loach could threaten the survival of the freshwater blenny (Salaria fluviatilis) and the colmilleja (Cobitis paludica).

The dojo loach or weather loach is, according to Clavero, one of the most recent introductions of an invasive species in the Iberian Peninsula. With a long, somewhat flattened body, it is a fish designed to live in waters with weak currents, where it feeds on snails and insect larvae. It can survive temperatures close to freezing, and tolerates very low levels of dissolved oxygen.

Although it is not so common in Europe, it is spreading in other parts of the world such as the Philippines, United States, Central Asia, Australia and various Pacific islands, where it is used as an aquarium fish, as well as for live bait and as a food source.


Story Source:

The above story is based on materials provided by Plataforma SINC. Note: Materials may be edited for content and length.


Journal Reference:

  1. Franch, Nati; Clavero, Miguel; Garrido, Montse; Gaya, Norbert; Lopez, Ver๓nica; Pou-Rovira, Quim; Queral, Josep Marํa. On the establishment and range expansion of oriental weatherfish (Misgurnus anguillicaudatus) in NE Iberian Peninsula. Biological Invasions, 2008; 10 (8): 1327 DOI: 10.1007/s10530-007-9207-9

Cite This Page:

Plataforma SINC. "New Invasive Fish Spreads Through The Ebro Delta." ScienceDaily. ScienceDaily, 20 January 2009. <www.sciencedaily.com/releases/2009/01/090114095105.htm>.
Plataforma SINC. (2009, January 20). New Invasive Fish Spreads Through The Ebro Delta. ScienceDaily. Retrieved July 29, 2014 from www.sciencedaily.com/releases/2009/01/090114095105.htm
Plataforma SINC. "New Invasive Fish Spreads Through The Ebro Delta." ScienceDaily. www.sciencedaily.com/releases/2009/01/090114095105.htm (accessed July 29, 2014).

Share This




More Plants & Animals News

Tuesday, July 29, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Deadly Ebola Virus Threatens West Africa

Deadly Ebola Virus Threatens West Africa

AP (July 28, 2014) — West African nations and international health organizations are working to contain the largest Ebola outbreak in history. It's one of the deadliest diseases known to man, but the CDC says it's unlikely to spread in the U.S. (July 28) Video provided by AP
Powered by NewsLook.com
Traditional African Dishes Teach Healthy Eating

Traditional African Dishes Teach Healthy Eating

AP (July 28, 2014) — Classes are being offered nationwide to encourage African Americans to learn about cooking fresh foods based on traditional African cuisine. The program is trying to combat obesity, heart disease and other ailments often linked to diet. (July 28) Video provided by AP
Powered by NewsLook.com
Asteroid's Timing Was 'Colossal Bad Luck' For The Dinosaurs

Asteroid's Timing Was 'Colossal Bad Luck' For The Dinosaurs

Newsy (July 28, 2014) — The asteroid that killed the dinosaurs struck at the worst time for them. A new study says that if it hit earlier or later, they might've survived. Video provided by Newsy
Powered by NewsLook.com
Raw: Sea Turtle Hatchlings Emerge from Nest

Raw: Sea Turtle Hatchlings Emerge from Nest

AP (July 27, 2014) — A live-streaming webcam catches loggerhead sea turtle hatchlings emerging from a nest in the Florida Keys. (July 27) Video provided by AP
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