River Deveron Smolt Tracking Project 2016

River Deveron Smolt Tracking Project 2016

The River Deveron DSFB (RDevDSFB) & Deveron, Bogie & Isla Rivers Charitable Trust (DBIT), in partnership with the Moray Firth Trout Initiative (MFTI) are to undertake a salmon smolt tracking project this spring. Smolts is the name given to young salmon (1-4 yrs old), moving down river to sea. The project will investigate the degree of smolt mortality between the upper Deveron and the estuary.

Working with Marcus Walters from the MFTI and Matt Newton from Glasgow University, the DBIT & RDevDSFB will embark on a smolt tracking project this spring (2016). Using rotary screw traps operated in the upper Deveron, 50 smolts will be caught and tagged with acoustic ID tags. Each tag emits a unique high frequency pulse, identifying the specific fish when detected by a receiver. Eleven receivers will be deployed along the length of the Deveron to track the downstream migration of the smolts through the river as far as the estuary at Banff.

This project will provide a huge amount of information to the DBIT and RDevDSFB on the migration and survival of smolts and should ultimately help to ensure Deveron smolts have an improved passage to sea. The project will quantify the proportion of salmon smolts making it out to sea. Measure the speed of downstream migrating smolts and identify any bottlenecks that are either delaying the smolt migration or specific locations that are resulting in smolt mortality.

At the 2015 RAFTS Conference Matt Newton (Glasgow Univeristy IBIS PhD candidate) gave an alarming presentation that found more than 85% of the smolts from the rivers Finn and Mourne, on the Northern Irish border, never made it beyond Lough Foyle and out to sea. Although previous studies on the Tweed have found high levels of smolt mortality (44%) at river barriers, Matt Newton’s study found very little impact from in river barriers but significant levels of mortality once the smolts reached the estuary.

Given the current poor numbers of Atlantic salmon returning to Scottish rivers to spawn, this level of smolt mortality is potentially very significant. The low numbers of salmon returning to our rivers is most likely driven by high levels of marine mortality which is often attributed to poor marine feeding, the Greenland fishery and pelagic trawlers. Previously the DBIT & RDevDSFB had felt there was very little that they could do about these far off marine pressures. However, if the level of smolt mortality seen in the Foyle or Tweed is potentially taking place in the river Deveron and immediate marine environment, then there may be management measures that the DBIT & RDevDSFB can deploy to ease their passage and improve the survival of smolts leaving the river.

The RDevDSFB & DBIT membership have kindly sponsored 40 tags and Muiresk Fishings have sponsored an additional 10 tags. The tags are very costly so the DBIT & MFTI would like to thank all supporters for funding this ambitious and ground breaking project.

www.morayfirthtrout.org & www.deveron.org