National Parks and Wildlife Service marine mammal expert Geoff Ross says sightings of 100 whales in a day were hard to ignore on and off shore.

‘‘As humpback whales increase and as a natural predator of humpback whales, I would expect to see the number of killer whales increase as well,’’ Mr Ross said.

Narooma Charters’ Darryl Stuart saw a pod of four or five killer whales three days ago near Montague Island.

‘‘On days where the whales are a bit hard to find, that’s the days you will find killer whales in the area. I think the (other) whales veer off a little then.’’

Mr Ross said people had also reported killer whales near Eden and further north, off Sydney’s northern beaches, about 12 kilometres out to sea.

People have also reported killer whales attacking seals off Dalmeny.

For sight-seeing vessels, a whale mugging - when humpbacks come up and nudge their boats - is as good as it gets. Mr Ross said this was a natural occurrence, but warned boat owners not to mess with mother whales on their annual southern migration.

‘‘They can be up to 40, 50 and even 60 tonnes and a cranky mother humpback or mother right whale is an animal your don’t want to mess with.

‘‘At this time of the year, when there are mothers and calves, keep to that 300- metre separation distance between vessel and animal and you will be on the safe side.

‘‘Some boat owners may not know they are messing with them. But just following them in too close, that will annoy an animal and can be enough to stir an animal to thinking her calf is at risk and she will respond aggressively.’’

Mr Ross said not being hounded and hunted and chased all over the planet these days had made sightings more likely, and there had been 907 more sightings this year than last year.

Volunteers at Cape Solander south of Botany Bay had recorded two peak days of sitings close to the record being 102 animals on July 6, 2011.

‘‘But this year we saw 101 whales, one off the record, but we saw that 101 on two separate dates this year - the 6th of July and 8th of July.’’

Friends of Durras spokesman John Perkins said this year’s migration was stunning, after seeing five humpbacks swimming parallel to one another off the main beach at Durras.

‘‘They were just motoring across the bay as if they had an outboard motor.’’

Mr Ross said since being protected from hunting in 1963, humpback’s recovery had been nothing short of marvellous.

‘‘We have a higher number of minke whales this year than other years. That’s always a good sign. They are a harder animal to spot. Whether you see them or not could be weather dependant, again the analysis bears them out, this just seems to be an interesting year for minke whales.

‘‘We saw 32 minke whales this year, we saw 17 in 2012 and 4 in 2011. That’s an upward trend, again it’s a small snapshot.’’