Missing Salmon Project

The interim report of the Atlantic Salmon Trust “Missing Salmon Project” Spey 2019 can be downloaded Spey MSP Report 2019

Spey River highlights

• Throughout the smolt run, a total of 170 smolts; 149 salmon smolts and 21 sea trout were tagged with acoustic tags (Vemco V7) over a 20-day period (13/04/2019 – 02/05/2019).

• The Atlantic salmon smolts had a mean fork length of 134.5 mm and a mean weight 24.0 g. The mean tag burden (% of body weight) was 6.7%. The sea trout smolts sampled had a mean fork length of 161.0 mm and a mean weight 43.3 g. The mean tag burden (% of body weight) was 3.7%.

• Of the 149 tagged salmon smolts, 88 smolts were estimated to have reached the downstream receivers and 69 smolts reached the Spey Bay array. The confirmed survival rate were 59.1% and 46.3% respectively.

• Overall, losses rate in freshwater was 0.82 %/km. The losses rate varied between 0.27%/km (receiver 131694) and 6.2%/km (receiver 126845).

• Freshwater receiver efficiency averaged 91.6%. Six receivers operating at over 98% efficiency.

• The median speed for confirmed migrants (e.g., smolts that were detected when crossing Fraserburgh array) was 0.07 m/s for the river travel, 0.24 m/s for the marine travel to the Spey array, and 0.35 m/s for the marine travel to the Fraserburgh array.

• Confirmed successful migrant smolts took a median of 8.1 days to travel from the release site to the most downstream river receiver, and 0.6 day from the most downstream river receiver to the marine Spey array. They took 1.8 days to reach the Fraserburgh array from the Spey array.

• Overall, the salmon smolts showed strong directional movement, heading east, north east.