A visit to the (Welsh) river Dee fish trap

by Stephen Greogry - sgregory@gwct.org.uk

Anton Ibbotson and Stephen Gregory of project Morfish recently paid a visit to the Cyfoeth Naturiol Cymru/Natural Resources Wales fish trapping facility on the river Dee in Chester.

Ian Davidson and Rich Cove kindly gave us a guided tour and showed us the fantastic facility in action.

The schematic below shows the trap which is located at the tidal limit. Ian and Rich are currently catching good numbers of both salmon and trout in the Dee.

 



The potential benefits of catching returning spawning fish are obvious to Anton and I. With the fish in your hand you're able to measure length and weight precisely and take biological material such as scales and fin clips.

 

We currently use a passive monitoring system for spawners meaning we detect the returns on either the adult counter or the PIT tag system. By having biological data on the returning spawners we would be able to investigate changes in the condition over time, allowing us to investigate possible drivers of stock sizes over time.

 

One last photo - Anton Ibbotson chasing fish around the trap floor:

 

Working towards a standard salmon stock monitoring programme

The GWCT's Stephen Gregory recently presented a talk on the recommendations for monitoring and modelling of salmon populations based on the shared experiences of scientific researchers working on Project Morfish.

The slides are below. Please contact Stephen on sgregory@gwct.org.uk for more information.

View Towards a standard salmon stock monitoring programme and other presentations by sgregory.

How to PIT-tag a salmon parr

Our state of the art research facilities on the River Frome include electronics that enable us to record the migration history of individual fish. Each September, since 2005, we have fitted 10,000 salmon parr with Passive Integrated Transponder (PIT) tags that transmit an individual barcode when a fish swims past one of our antennae.

Approximately 10% of the Frome salmon population is fitted with PIT tags, helping to make the River Frome salmon population one of the most comprehensively studied in Europe.

This is how we tag the salmon:

1. The parr are caught by electro-fishing. Two teams work on the river for three weeks until 10,000 parr have been tagged. An average of 400 parr are tagged each day per team.

2. The fish is anaesthetised and the length and weight are recorded. Scales are collected and are used to look at growth rate, age and to determine sex.

3. A small insertion is made with a scalpel and a PIT tag is inserted into the body cavity where it will remain for the lifetime of the salmon.

4. The fish is transferred to a holding tank to recover before being released into the 100-metre section where it was caught.

Our salmon work

We're conducting vital research into what is causing the decline in salmon numbers with the ultimate goal of reversing that decline...

Click here to find out more >

Salmonids in the floods

You may have noticed we're experiencing a bit of wet weather at the moment in the UK with flooding heaping misery on people across the country.

Flooding on the River Avon at GWCT HQ in January 2014

Whilst the effects of flooding on humans are all too obvious, we are not the only species to be affected by floods. Fish inhabit the very rivers that are bursting their banks onto the surrounding towns and countryside. Unlike humans, however, fish have been experiencing floods in their native river habitats for hundreds or thousands of years. And because floods present a strong evolutionarily selective force (you adapt or you die), fish have adapted to survive and even thrive under certain flood conditions.

Salmonids are a good example of a group of fish species that have adapted to local flow regimes...

Read full article on our website >

New Presentation: Salmon Research at the River Frome

The slides below are taken from a recent presentation covering the salmon research that the GWCT are currently conducting on the River Frome. The presentation took place at West Stafford Village Hall and was given to the Dorset Chalk Stream Club on the 20th December:

You can find out more about the Dorset Chalk Stream Club here and there are photos from the talk on John Aplin's blog.

New Photos from the GWCT Salmon & Trout Research Centre

Three of our newest members of staff visited our Research Centre at East Stoke on the River Frome this morning and took a few pictures:

The counting station on the Frome where adult salmon are recorded.

Senior Fisheries Scientist William Beaumont demonstrates some of the equipment used to monitor fish.

A pipe from the compressor used to create the bubble curtain that helps separate large and small fish for monitoring purposes.
 

 

First MorFish newsletter published

The first MorFish newsletter has been published by the Game & Wildlife Conservation Trust.

The newsletter details the work our scientists are conducting in partnership with fisheries scientists at INRA, a French government research agency.

Click here to download newsletter >

Introducing the MorFish Project

Atlantic salmon populations have declined considerably across much of North America and Europe since the 1990s, some by over 70%.

We’ve joined forces with a team of French scientists at Institut National de la Recherche Agronomique (INRA), and will be monitoring Atlantic salmon populations over the next three years.

The aim of the project, entitled MorFish, is to harmonise and therefore improve the way salmon data is collected and analysed across three rivers – the Frome, the Scorff and the Oir.

This will provide us with a better understanding of the causes of salmon population decline and inform us on how we can help the management of that decline.

Click here to learn more >