Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Elver fishing multiplies the accidental capture of other fish by eight

09.05.2008
In the Ebro River delta, the fishing of elver (Anguilla anguilla) leads to the accidental capture of other fish species, with the capture of one ton of elver possibly resulting in the capture of up to 8.2 tons of accompanying species. Researchers from the Institute for Agro-Food Research and Technology (IRTA), who have assessed the effects of this method of fishing and identified the most fragile species, propose improvements in current methodologies.

With the capture of elver, eel (Anguilla anguilla) fry, scientists have identified up to 17 fish species, apart from the eel, which on average die in 36.5% of cases. The “dramatic” situation of accompanying ichthyofauna (fish captured with elver), which represents 43% of the various types of species in the area studied (350 Km²), may lead to ecological imbalances since it is the smallest specimens that are most likely to die when captured.

Enric Gisbert, main researcher of the study to be published in the next edition of the magazine Hydrobiologia, explained to SINC that improvements are necessary in fishing methods to “reduce the mortality of accompanying ichthyofauna associated with capture processes and initial elver selection, as well as increase the sustainability of this activity”.

Fish species accidentally affected by elver fishing in the estuaries and coastal lagoons of the Ebro delta include mullets (fish normally found in ports or estuaries) and, in particular, the fry of Liza ramada, Liza aurata and Mugil cephalus, species which, according to the research, share part or their entire recruitment calendar with the elver fishing season.

In addition, researchers have shown that “the impact of elver fishing is not only on migratory species but might also ultimately affect resident species, as well as other strictly limnetic species”.

According to the data obtained for the two-year project, it has been determined that for every one ton of elver captured, 8.2 tons of other fish species are accidentally fished too, without taking into account illegal fishing which could make up between 20% and 25% of captures.

Gisbert puts the mortality of species captured during the elver manual selection process down to “not very careful or delicate handling by the fishermen, i.e. excessively harmful, worsened by the effects of prolonged immersion that causes lack of oxygen (anoxia) in fish”.

More sustainable fishing methods

The study shows the need to consider the impact of elver fishing at a population, trophic and ecosystem level. The IRTA researcher, together with Miguel Ángel López from the Department of the Environment at the Generalitat de Catalunya (Catalan autonomous government), pointed out to SINC that “actions which promote the reduction of the collateral effects of fishing and the selection of elver must be introduced”.

Among the most relevant actions, “informing fishermen so that they are aware of the impact of their activity appears to be a priority”. Researchers also stress that “methodological and procedural changes should be introduced in elver handling and selection tasks”. In this case, scientists suggest that a reduction in handling time and maximising care in selecting fish could avoid the death of many fish captured by accident.

In addition, an improvement in the design of fishing nets used for “highly” selective fishing might be another solution as this would “only target the species to be fished”, said Gisbert. According to the researcher, this method has been proved “experimentally” in situ, with “very promising” results. A simple alteration was made in the design of the fishing net, which significantly reduced the handling and selection time of elver, accidental captures, number of accidental species rejected during fishing and, naturally, deaths.

This work could “serve as a basis to the administration for implementing measures which guarantee a far more sustainable exploitation of this natural resource”, concluded Gisbert and López.

SINC Team | alfa
Further information:
http://www.plataformasinc.es

More articles from Ecology, The Environment and Conservation:

nachricht Bioinvasion on the rise
15.02.2017 | Universität Konstanz

nachricht Litter Levels in the Depths of the Arctic are On the Rise
10.02.2017 | Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung

All articles from Ecology, The Environment and Conservation >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

Impacts of mass coral die-off on Indian Ocean reefs revealed

21.02.2017 | Earth Sciences

Novel breast tomosynthesis technique reduces screening recall rate

21.02.2017 | Medical Engineering

Use your Voice – and Smart Homes will “LISTEN”

21.02.2017 | Trade Fair News

VideoLinks
B2B-VideoLinks
More VideoLinks >>>