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Project Code [2005-PHD5-B-18]

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Project title

Characterisation of Arctic char spawning grounds in Irish lakes and the vulnerability of ova to environmental change.

Primary Funding Agency

Environmental Protection Agency

Co-Funding Organisation(s)

n/a

Lead Organisation

University College Cork (UCC)

Lead Applicant

John Davenport

Project Abstract

The Arctic char (Salvelinus alpinus) is at the southern margin of its natural distribution in Ireland. Although the country has lost approximately one third of its documented char populations the mechanisms involved remain largely unresolved. Following the precise determination of spawning sites in four lakes of differing productivity experiments were conducted to explore spawning requirements and threats affecting the early life stages. The threat of increasing winter temperatures was highly evident as mean temperatures in the spawning substrata during the incubation period were at the level above which mortality has been shown to greatly increase. The brown trout (Salmo trutta) which co-occurs with all Irish char populations was found to predate strongly on Arctic char eggs with individual trout capable of ingesting the entire egg output of a single Arctic char female. Predation levels appeared to be greater in enriched lakes due to an increase in trout abundance and size. The Arctic char (Salvelinus alpinus) is at the southern margin of its natural distribution in Ireland. Although the country has lost approximately one third of its documented char populations the mechanisms involved remain largely unresolved. Following the precise determination of spawning sites in four lakes of differing productivity experiments were conducted to explore spawning requirements and threats affecting the early life stages. The threat of increasing winter temperatures was highly evident as mean temperatures in the spawning substrata during the incubation period were at the level above which mortality has been shown to greatly increase. The brown trout (Salmo trutta) which co-occurs with all Irish char populations was found to predate strongly on Arctic char eggs with individual trout capable of ingesting the entire egg output of a single Arctic char female. Predation levels appeared to be greater in enriched lakes due to an increase in trout abundance and size.

Grant Approved

�75,000.00

Research Hub

Natural Environment

Research Theme

Sectoral Impacts on Biodiversity

Start Date

01/10/2005

Initial Projected Completion Date

18/08/2011