Tuesday 21 April 2009

Limited access may protect lakes from alien species - study

RESTRICTIONS on access to Lough Carra and Lough Mask has been recommended in a new biosecurity plan for Lough Mask. The report was commissioned to try to protect the lakes from “alien species” that have invaded Lough Corrib.

Mandatory boat registration and appointment of water keepers has also been advised in the report by RPS Consultants for the Western Regional Fisheries Board. All three lakes have significant angling resources, and are designated under the EU habitats and bird directives.

The zebra mussel and the invasive waterweed Lagarosiphon major are among non-native species that have put a strain on the freshwater habitat of the Corrib.

Such species can have economic costs, in terms of prevention and control, and can also compromise the environmental status of the lakes, the report points out.

Angling, the location of fish hatcheries, pet shops and garden centres and research and management activities are identified as ways that biosecurity threats can travel.

The report identified 80 non-native aquatic species as posing a potential threat, with some 10 species designated as “high” or “very high” risk. Movement of contaminated trailers, boats, angling equipment and float tubes can have an impact, it says. Disposal of unwanted plants or the release of unwanted exotic fish can “seriously threaten” the lakes’ ecosystems.

It says there is “unlimited potential” for intentional introduction, due to unrestricted access, but says that unintentional introduction is the “most likely pathway”.

Natural spreading through water is the “least likely” pathway, it says. This is because Lough Carra is a spring-fed lake with only a few inflowing rivers and Mask is linked to Corrib by a karstic underground system that is not likely to facilitate natural spread.

The study recommends a registration system for boats and restriction of access to a number of designated launch points. A code of practice should also be developed to raise public awareness, it says. Monitoring to facilitate rapid eradication should take place, with the appointment of water keepers to support this.

Several regional fisheries boards – due to be reorganised under a new national authority – have called for legislation to deal with alien species. The report supports the view that legislation is required. It also notes that there is no central database for recording and tracking the occurrence of invasive species, but says this is being developed by the National Biodiversity Data Centre.

The Western Regional Fisheries Board has distributed the report to stakeholders, including angling clubs. Chief executive Dr Greg Forde said it was “high time” that biosecurity zones were created to protect habitats.

Irish Times


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