Fishermen and dolphin experts are reporting that migratory salmon are arriving later than expected to rivers in the Highlands.
Killer whales have been spotted in the Pentland Firth
Charlie Phillips, of the Whale and Dolphin Conservation Society, said the fish were three to four weeks late.
He said dolphins have just begun their first real hunting for salmon off a popular wildlife watching spot.
Meanwhile, minke whale and orcas - also known as killer whales - have been spotted in Highland waters this year.
The Moray and Cromarty firths are home to bottlenose dolphins.
Mr Phillips said: "There has been a dearth of salmon. I was talking to some fishermen and said the fish are late.
"I've been up to Chanonry Point where there were nine or 10 dolphins throwing around some reasonably large fish - which is the first proper hunting."
Chanonry Point is popular site with people who want to watch the marine mammals.
He said the dolphins were in a "search pattern" looking for food to give them adequate calories and proteins.
"May be the salmon are just very late and we are in for fantastic middle of July, August and September."
Elsewhere, there have been sights of orcas in the Pentland Firth, where they are hunting for seal pups, and minke whale have been spotted off Cromarty.