The University of Southampton is undertaking some ground-breaking work in this area which will help our understanding of the ocean distribution of Salmon from UK rivers.
The work all centres on scale samples from Salmon. Scales are taken from the Salmon and microscopic slices of scale from these samples are burned off with a laser beam which enables the varying chemical composition of the scale to be analysed; the variation reflects the different parts of the fish’s life cycle: the different chemical compositions are of the different waters that the fish has traversed through and lived in. The University of Southampton’s study is using baseline ocean temperatures, recorded via satellites, and the chemical composition of the food consumed by the Salmon whilst at sea to match up with the scale samples from the fish and ascertain the way in which the scale is laid down.
A fish scale can tell us so much about the life and movement of an individual
The process allows fish passage to be discerned and can help establish where fish from different rivers go to feed at sea; Salmon & Grilse do not necessarily go to the same feeding grounds out in the oceans.
Tweed is taking part in this exciting new work and, as the River has been collecting scales for 20 years, it has a very large scale ‘tissue bank’ to access. The Tweed Foundation has supplied the study with sets of scales from Grilse and Salmon from those 20 years and from different times of year, as well as scales from fish with a lot of growth checks (stunted fish where food has perhaps been hard to find).
The results from the study will be very interesting and describe a lot more about Salmon behaviour at sea.
Further information about the study can be found on the University of Southampton’s website HERE
and a copy of their leaflet, Marine Life of Atlantic Salmon: Evidence from the chemistry of scales, can be downloaded as a pdf document below.
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