Here's some mid-week motivation for you.

Giant salmon are swimming through rivers, leaping over rapids and jumping over man-made weirs to head upstream so they can breed.

Salmon running up the Don River in central Toronto. <a href="https://twitter.com/hashtag/toronto?src=hash">#toronto</a> <a href="https://twitter.com/hashtag/donriver?src=hash">#donriver</a> <a href="https://twitter.com/metromorning">@metromorning</a> <a href="https://t.co/mH1PA7bKbF">pic.twitter.com/mH1PA7bKbF</a> —@michaelibarry

"You see these massive fish swimming through very shallow portions of rapids, so you hear splashing and their tails flailing about," said Cameron Richardson, a project manager with the Toronto and Region Conservation Authority (TRCA).

Chinook salmon are native to the Pacific coast and were introduced to rivers in this region in the 1950s.

They are heading from Lake Ontario to suitable breeding grounds.

"These fish have natal homing, which is still a bit of a scientific mystery, where they return to the exact same streams they hatched in as young fish," Richardson said Wednesday on Metro Morning.

<a href="https://twitter.com/metromorning">@metromorning</a> big salmon in the Don River Sunday Sept 18!!! <a href="https://t.co/qecKgtnvDB">pic.twitter.com/qecKgtnvDB</a> —@Sioflynn

Perhaps the most impressive part of their journey is the fact that these not-so-little guys are doing it all without any food.

"This is just from sheer power. They are working on fat reserves that they have built up throughout the year," said Richardson. "They're not eating to replenish the energy they are wasting."

According to Richardson, some of these fish can grow to more than three feet in length and weigh up to 50 pounds. The end game, however, is simply to breed — and that's it.

"These Chinook salmon are actually terminal spawners, so shortly after reproducing upstream they actually end up dying," said Richardson. "If they don't make it to the suitable breeding grounds then that's it for them. They're not going to have any of their progeny survive."

Weekend salmon festivals

Seeing so many of these fish in the rivers is a good indicator that the rivers are improving in health, said Richardson, adding that Torontonians can spot the salmon these days in rivers across the city and the GTA.

The TRCA is also hosting two salmon festivals this weekend as an opportunity for people to see the salmon go upstream.

One festival takes place Saturday at 10 a.m. at Duffins Creek, in the Greenwood Conservation Lands in Pickering. Another one is being held on Sunday afternoon, at Highland Creek in Morningside Park in Scarborough, at 1 p.m.