Assessing the impacts of the New Tyne Crossing.

Project Name

Assessing the impacts of the New Tyne Crossing by modelling the dynamics of fish populations and levels of exploitation of migratory salmonids in the river Tyne.



Start Date

2010 - 2013

Project Collaborators

Environment Agency


Environment Agency

Project Description


Salmon and Sea Trout are anadromous, migratory species of high importance in the UK where they are exploited for sport and food. They breed in freshwater, yet have a marine stage to their lives, where most of the growth and development occurs prior to returning to their natal river to breed.  Both species demand very high water quality and specific habitat criteria. Pollution and other anthropogenic impacts can impact on the physical and chemical nature of the river environment, e.g. increased Biological Oxygen Demand, which can lead to significant negative impacts on both species.  Whilst improvements in water quality and more sensitive river management and appropriate land management have resulted in the restoration and improvement of migratory salmonid stocks and increased catches, factors determining yearly return and catch are not well understood. The river Tyne is among the best English rivers for salmon rod fisheries in England and Wales, with over 4600 fish caught in 2010.  

In 2009 work began to construct a second underwater crossing of the river Tyne between East Howden and Jarrow. The construction phase had the potential to cause considerable disturbance to the river bottom though dredging and removal of material.  While strict controls were put in place to regulate both the timing and immediate impact of the works it is not known what the overall impact was on fish returning to the river during the construction period. The Tyne & Wear Integrated Transport Authority (TWITA), the developers of the New Tyne Crossing Scheme has funded enhanced fishery monitoring including upgrading of the Riding Mill upstream (adult fish) trap, provision of a rotary screw trap to sample emigrating smolts and improvements to the electronic counter. TWITA has also funded a programme of fish tracking (‘River Tyne Crossing Salmon and Sea Trout Tracking Programme’) and the setting up of a logbook angler catch recording scheme.

This project will make use of these data routinely collected by Environment Agency to develop time-series models of the Tyne Salmon and sea trout populations by analysing trends in fish returns (the population of the fish as they return to reproduce); recruitment; smolt and kelt populations and harvest (fishing catch) data. The study will seek to determine what factors are responsible for the pattern of migration of fish observed in the river. Using these models we will analyse the impact of the tunnel excavation on the observed trends of fish returns and any subsequent impacts on population size for both salmon and migratory trout.