Using biochronologies and chemical tracers to track salmon movements and growth in a changing world

Supervisors

Dr Anna Sturrock (University of Essex - [Email Address Removed])

Dr Eoin O’Gorman (University of Essex)

Nora Hanson (Marine Scotland)

Rachel Johnson (NOAA/UC Davis, USA)

Colin Bull (University of Stirling/Atlantic Salmon Trust)

Collaborators

Tim Sheehan (NOAA, USA)

Rasmus Lauridsen (Game & Wildlife Trust)

Marcus Walters (Deveron, Bogie and Isla Rivers Charitable Trust)

Russell Poole (Marine Institute, Ireland)

Chris Conroy (Atlantic Salmon Trust)

Philip Rudd (Environmental Agency)

Jonathan Archer (Tweed Foundation)

Clive Trueman (University of Southampton)

Alexia Maria Gonzalez Ferreras (IH Cantabria, Spain)

Background

Salmon have great cultural, economic, and ecological value, yet they are experiencing unprecedented declines. Changes in the marine environment are often cited as the primary cause of population crashes, yet we still have large gaps in our understanding about their migration pathways and foraging strategies at sea. We also have large gaps in our understanding about how the freshwater phase of the lifecycle affects marine survival (so-called “carryover effects”), for example by influencing growth and migration size/timing, potentially resulting in juveniles being mismatched with marine prey availability. The importance of different stressors also varies over their geographic range, with lower latitude populations exposed to increasingly high river temperatures.

Approach

This PhD will use archival tissues (otoliths, eye lenses, scales) that encompass both freshwater and marine phases to understand the factors driving life history choices and mortality in salmon. The successful student will use state-of-the-art techniques on Atlantic and Pacific salmon from multiple populations and countries (including the UK, Ireland, Spain, Greenland and USA) to reconstruct patterns in habitat use, migration phenology, growth rate and diet. They will use these data to explore intraspecific variation in movement and growth to reveal carryover effects and identify factors associated with poor return years. There are extensive samples and data already in hand, but the student will also have the opportunity to travel to the study sites to collect additional samples.

Training

The candidate will join the Ecology and Environmental Microbiology Group at the University of Essex and will benefit from the broad expertise offered by the large team of supervisors and collaborators (listed above). The student will be trained in a variety of laboratory, field, data analysis and science communication skills that are transferrable across a range of career paths. Specific techniques include otolith, scale and eye lens preparation, trace element and isotopic analyses, bioimaging, growth analyses, and Hidden Markov and machine learning modelling.

Person specification

We are looking for a candidate who is enthusiastic about fish ecology, global change biology, quantitative ecology, freshwater and/or marine biology, with a degree in biology, zoology, ecology, environmental sciences or chemistry.

How to apply

Please email a CV, University grade transcript and cover letter to [Email Address Removed]