The Tweed Foundation is a partner to a new project called "Living North Sea", an Interreg lVB North Sea Region Programme, European-funded, two-year project principally to discover more about the North Sea Sea-trout stocks.  Partners to the project include scientific research organisations from Holland, Belgium, Sweden, Denmark, Norway and Germany, as well as England and Scotland. As such, a PhD student is sought for the project, details of which follow.

Migratory behaviour and survival of Atlantic salmon and Sea-trout stock components

Where they occur in large rivers, Atlantic salmon Salmo salar and sea trout (the anadromous form of brown trout Salmo trutta) stocks often contain several distinct components, characterized by factors such as genetic distinctiveness, life cycle characteristics and migration patterns. Understanding the characteristics and contributions of these stock components is fundamental to conservation and management of exploited stocks in these rivers. This project will use acoustic telemetry and PIT (passive integrated transponder) tagging to measure migration patterns and the fate of downstream migrating juveniles and upstream migrating adults of several distinct salmon and sea trout stock components in the River Tweed, a Special Area of Conservation in the Scottish Borders. This will be linked to information on age, growth and identity of the stock components. As part of this work we aim to measure exploitation rates by anglers as well as other losses on adult salmonids and predation rates by birds and fishes on juveniles. The outputs will be used to improve model assumptions on survival rates and abundance for stock components in the river.

The project, funded largely through the EU, is a collaboration between the Tweed Foundation (Dr Ronald Campbell) and Durham University (Dr Martyn Lucas) and fieldwork will be based from the Tweed Foundation’s headquarters in the river locality. The student will benefit from training in field research, fisheries management, experimental design and communication across both institutions and will have access to state of the art resources, within a highly active research environment.

Specific project objectives and preliminary methods

 The study has two principal aims:-

(1)  Determine the migration pattern and mortality of sea-trout and salmon smolts from different stock components during their migration downriver, including the sources and levels of predation experienced by these.

(2)   Determine patterns of migration and in-river mortality of adult salmon and sea-trout from different stock components, in particular of those that have been externally tagged to determine exploitation rate by anglers and losses due to other causes. Angler exploitation rates have been measured using externally tagged fish for over ten years, but there is no usable information as yet on what other sources of in-river mortality there might be.

To determine these parameters this study will:-

(1)    Acoustic tag salmon and sea-trout smolts at sites on two upper tributaries. The Yarrow is a tributary of the Ettrick, the main upper tributary of the Tweed and the Gala Water is a smaller tributary that enters the Tweed only a few kilometres downstream from the Ettrick.  The Yarrow Water’s salmon stock is dominated by spring salmon (multiple winters at sea) while the Gala Water has summer-autumn grilse (one winter at sea), enabling us to test our null hypothesis that the downstream migratory behaviour and survival of these stocks is identical. We expect that this will include an element of pre-smolt, autumn migrants to establish how these move within the river. This, together with tracking of spring-migrating smolts will give the first information on how smolts use the Tweed estuary and make their transition to salt water in it, enabling testing of hypotheses concerning selective tidal stream transport and effects of river discharge on emigration rate. There may be areas of difficult passage for smolts on the main river, especially during dry springs, which it would be of great importance to management to identify.

         The two major sources of predation on smolts and pre-smolts are thought to be avian predators, especially sawbill ducks Mergus and some cormorant (Phalacrocorax carbo) and large resident trout (S. trutta). We will seek to determine the degree to which mortality by predators can be distinguished from other sources of mortality. This will include scanning of local stillwaters with acoustic receivers, and around bird colonies with PIT gear (using larger samples of PIT tagged fish than is possible for acoustic tags), counts and distribution of piscivorous birds and  gastric lavage of trout        

Handling mortality of smolts will be a confounding factor in determining in-river mortality rate. The trapping sites on the Yarrow and Gala are both fish farms, so samples of tagged smolts can be kept for a period after tagging to assess tagging effects.  Multiple detection sites on the Yarrow / Ettrick will also enable mortality rates to be measured only from fish leaving the tributaries and entering the main river.

(2)      Acoustic tag fresh-run adult salmon and sea-trout on the lower Tweed and monitor their progress upstream to measures rates of movement in relation to environmental factors, as well as levels and  sources of mortality. Salmon and sea-trout have been externally tagged at the bottom of the river since 1997 to assess recapture rate by anglers, but there is no information on non-angler mortality of such fish. This will also give information on the movement of fish within the river and on where the fish tagged at different times of year go.  These fish would be obtained from anglers early in the season (Feb to July) and from netting stations in the estuary from July onwards.

Outputs:    Findings will be communicated through academic journals, conferences and popular forums to a wide range of stakeholders, and through a PhD thesis. A key output of the project for the Tweed Foundation will be to provide statistics on survival and behavioural segregation of stock components, that can be used to improve the modelling of the salmon and sea-trout populations of the Tweed and so help to safeguard these important populations and the economically important fisheries that depend on them.

Candidates should hold at least an Upper Second Class degree, or its equivalent in European countries, be able to communicate and write well in English and be competent in data analysis and interpretation. Experience in fish ecology, fisheries management and/or wildlife telemetry would be advantageous. A clean driving licence is essential and boat handling and diving experience may be useful. The applicant should be a good team worker, keen on working in wet, outdoor environments and have an ability to communicate effectively with a wide range of stakeholders, including landowners, commercial fishermen, anglers and the public. An ability to speak German or Danish would be an advantage.

IMPORTANT : APPLICATIONS SHOULD BE MADE THROUGH THE WEBSITE OF FindAPhD.com

Neither applications, nor application forms, are available from either The Tweed Foundation or Durham University

The project is due to start on 1 January 2010 and interested applicants can obtain further information from:

Dr Lucas (m.c.lucas@durham.ac.uk) or Dr Campbell (rcampbell@tweedfoundation.org.uk).

Details of the two institutes and research can be found at:

http://www.tweedfoundation.org.uk