CITIZEN SCIENCE
Lifestyles BY ANNE SUNDERMANN
of the
B
rown trout and its saltwater sibling the sea trout are incredibly successful in Irish waters. Resident since the post-Ice Age period (about 14,000 years ago) when glacial melt created viable fresh and brackish waterways in Ireland, members of the salmonid species Salmo trutta are an incredibly adaptable and important fish. All modern S. trutta in Ireland are born in freshwater, where they develop into fry. When S. trutta fry reach a certain age, they reach a developmental decision point: stay close to home and enjoy the comforts of a freshwater lifestyle or head out and make a life on the high seas for a season or two of growth and maturation (known as the anadromous path). Regardless, all must return to a freshwater base to spawn. The resident freshwater juveniles (primarily male) are found in almost every waterway on the island and may stay resident in their natal waterway or migrate locally. They are not selective in diet and live in healthy numbers in various locations from mountain rivers and lakes to brackish coastal streams and bays. Their colouring remains the speckled brown, darker or lighter to blend with surroundings. Brown trout spawn in 26
Irish Wildlife Autumn ‘21
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