2015 Forums & Talks
Two of Irelands prominent fish experts, avid fly fishermen and great supporters of our Fair and its ethos held talks and discussion sessions on both days of the fair.
On Saturday and Sunday morning Prof. Ken Whelan held a talk and discussion session titled "Where have all the fishes gone?" and On Saturday and Sunday afternoons Dr Robert Rossell gave a further talk and discussion session titled "problems with providing scientific management advice for sea trout".
The problems of providing scientific management advice for sea trout
Robert Rosell, Agri-Food and Bio-Sciences institute for Northern Ireland.
Sea trout have highly variable life strategies . Like salmon, they breed in freshwater and migrate to a growth phase at sea. While they may move long distances at sea, they do not have the salmon’s systematic long migration to distant northern feeding grounds. Additionally, many return to fresh water in their first autumn after spring emigration, often as immature non breeding fish. Once past this phase, they can live for many years with regular spawning migrations to freshwater and return to sea.
This life history creates problems for the scientist trying to advising fishery managers. On the plus side, repeat spawning and return to sea means that an individual does not need to breed successfully on a single opportunity to reproduce , and there may be second (and third or more) breeding opportunities . On the other hand, runs to fresh water contain many more maidens or immature finnock than older repeat spawners . Scientific advice on management and harvest targets requires more information than for the simpler brown trout and salmon life cycles, with reference points for Large multiple spawners, finnock and fry and parr in rivers. There is also a problem in separating fish in rivers into resident and migratory components.
With knowledge of sea trout biology considerably behind that of brown trout and salmon, this talk will outline the current approach in Northern Ireland and where we need to be to provide scientifically based management advice, with particular reference to County Down rivers and streams. Local habitat – based restoration experiments and opportunities will be discussed.