Modelling the availability of small pelagic fish to birds and marine mammal predators off the east coast of Scotland.

Marine top predators (seabirds, seals, whales and dolphins) are iconic symbols of a healthy marine environment and support eco-tourism which is a vital industry for coastal communities around Scotland. Top predator populations reflect variations in small pelagic fish (sandeel, sprat and herring) on which they depend, and as a result are vulnerable to both fishing and the predicted effects of climate change. For most of their life cycle, sandeel live buried in sandy sediments and produce eggs which stick to the seabed. In contrast, sprat live entirely in the water column and shed eggs which float and drift with the water currents. Both sandeel and sprat larvae are dispersed by currents, but when they reach ~30mm in length sandeel larvae must find a new patch of sand in which to bury or they cannot survive. The other main difference is that sandeels survive through the winter buried in the sand without feeding, whilst sprat continue to feed all year around. Rising winter temperatures are thought to place stress on overwintering sandeels and compromise their survival.

This project will develop mathematical models of the contrasting life cycles of sandeel and sprat, and use them to investigate the consequences fishing and climate change for their population dynamics off the east of Scotland. The key question to be addressed is “how will the balance between sandeel and sprat as food for top predators off the east coast of Scotland affected by fishing and climate conditions?” The basis for models to tackle this problem comes previous research at Strathclyde to investigate the spatial population dynamics of plankton and cod. This project will develop these models to represent sandeel and sprat by simulating dispersal patterns of larvae from the outputs of ocean circulation models, and link these with models of the settlement, growth and spawning of individuals which survive. The project will involve assembling data and knowledge of distribution, behaviour and biology of sandeel and sprat, translating these into the mathematical functions needed in the model, drawing together data sets for fitting and validation, and conducting experiments with the model to address the project aims.

The project would suit someone wishing use and develop his or her quantitative skills towards a career in fisheries science or mathematical ecology. Candidates should possess or expect to obtain a first class honours degree or a postgraduate qualification in applied mathematics, statistics, or any quantitative natural science.

The student will need to spend some time at the Marine Scotland Science Laboratory in Aberdeen learning about sandeel and sprat life history and fisheries. It is likely also that there will be opportunities for the student to participate in new data gathering at sea as part of Marine Scotland monitoring surveys.

The project will be co-supervised by Prof. Mike Heath and Dr Douglas Speirs (Strathclyde), and Dr Simon Greenstreet (Marine Scotland Science). The student will be principally based in the MASTS Marine Population Modelling Group at Strathclyde University (http://www.mathstat.strath.ac.uk/research/groups/pme/mpm).