A Scottish fishery board has stepped up its efforts to monitor for an invasive species of salmon.
Non-native pink, also known as humpback, salmon have been spawning in the River Ness near Inverness.
Ness District Salmon Fishery Board has been using a drone fitted with a camera to spot redds, the nests female salmon create in river beds.
The board, which has already filmed pinks spawning, counted 15 redds in a single day earlier this week.
The fish are native to Pacific Ocean waters.
Pink salmon have recently been caught by anglers in other Scottish rivers including the Helmsdale, Dee and Spey.
The fish are believed to be related to pink salmon introduced to rivers in Russia in the mid-1950s.
These fish have since gone on to be found in rivers in Scandinavian countries, including Norway.
Salmon and Trout Conservation UK and Prof Eric Verspoor, director of the Rivers and Lochs Institute at Inverness College UHI, have warned of the potential risk to native salmon.
Threats include competition for food.
In North America, one of the areas where pink salmon are native, they are a favourite prey of grizzly bears.