Scale Sampling for Salmon, Sea Trout and Brown Trout

To help better understand our resident and migratory fish The Committee would like to request that members, whenever possible, collect scale samples from as many fish as possible. Once enough samples have been collected they will be sent to the Freshwater Research Laboratory at Pitlochry to be read.

How to collect a sample

Samples can be taken from fish that are returned as well as those retained, it is believed to cause no lasting harm to the fish and new scales grow to replace those taken. When taking a sample a few pieces of information about the fish are also required and the scales cannot be properly read without them, the crucial ones are

Also useful are girth, weight, sex if it can be determined and any comments, for example injuries or damage to the fish. The image shows the area from which the sample should be taken, however if scales are already missing from this area you should move forward or use the same place on the other side of the fish, it should be recorded though if the sample was collected from anywhere other than from this area.

1. Date and Place of Capture.
2. Species.
3. Lenght to fork of tail.

 

The process of taking the sample is straight forward. The back of a small knife should be used to scrape the mucus from the area to be sampled and then the blade run back against the scales several times to lift and remove a small number, 10 -20 being adequate. The blade should then be inserted into a paper enelope and the envelope pinched against the blade to remove the scales as the blade is withdrawn. The sample should then be kept somewhere warm to allow it to dry fully before being stored. The recommended number of scales ensures that there will be a high chance of having a few scales which are the true age of the fish and not only ones that have been damaged or are replacements of ones lost previously.

Further information and details of how the scales are read and the information they contain “de-coded” is available from Ally Gowans excellent website, to which he has kindly allowed us to provide the following link (www.letsflyfish.com/scales.htm). The Club Treasurer will be very pleased to recieve further samples and will be storing them until the close of next season, for further information please contact treasurer@fishalmond.co.uk for further information and storage.