Can we expect to see more sharks turning up off our beaches this summer?

Reports indicate more sharks turning up already, and it is early in the "shark season".

Regular Manukau Harbour fisherman Harold Chapman said this week he had never hooked so many big sharks while snapper fishing on the harbour.

"I have been fishing there for 40 years and never seen so many big ones. These are not babies — they take your bait and are like freight trains. I lost five baits in a row."

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The harbour is well known as a breeding ground for big female sharks, like bronze whalers and great whites, which come into inshore water to have their young as it is a safer environment. It is not uncommon to hook baby sharks on snapper baits. But the adults are a different proposition, and will take hooked fish as well as large baits and there is nothing the angler can do but hang on and hope the line breaks.

The Manukau has a long history of huge, 6m great whites caught on set lines, and legendary stories tell of how they were pulled ashore by a tractor in the 1950s and '60s.

But they are babies compared to a beast that roamed the oceans for 20 million years.

Dubbed "Big Tooth" by scientists, Megalodon was a giant that lived from 20 million years ago to two million years ago. Great whites evolved 10 million years ago, and have survived. But nothing like Megalodon. It was the size of a bus, and equipped with razor-sharp teeth; an apex predator fearing nothing, but has left little evidence.

The biggest great white today measures 6m and weighs 1800kg. Megalodon grew to 15-17m and weighed about 45,000kg — or 45 tonnes. Research based on fossilised remains confirms Megalodon had 24 upper teeth and 22 in the lower jaw, and was not actually a great white.

Today, shark numbers may be increasing as bans on taking sharks help boost numbers internationally, and anecdotal evidence also suggests that international restrictions on fishing vessels carrying shark fins, which includes New Zealand, may be reducing the slaughter for the shark fin soup trade in Asia.

One of the most comprehensive studies compiled on illegal shark killings by researchers at Dalhousie University in Halifax, Canada in 2013, estimates that 100 million sharks are killed every year around the world, a number that exceeds what many populations need to recover.

The bans on vessels carrying shark fins may finally be reducing the slaughter of sharks.

Anecdotal evidence suggests this may be helping boost shark numbers. And great white sharks are now protected in many countries, including New Zealand, although they roam international waters and are vulnerable in international waters.

Freshwater
Fishing has picked up on Lake Rotoiti since the season opened, with deep trolling producing the best results. Those anglers using wire or lead lines, or downriggers, have been catching good bags of trout in top condition. Harling at dawn or dusk is also worth trying.

But jigging is proving difficult, and this is not expected to improve until closer to Christmas when water temperatures rise and the lake stratifies, creating a thermocline where the fish congregate in large schools. Fly fishermen fishing the Ohau Channel have also been taking some large brown trout, with two over 4.5kg caught one night.

Tip of the week

It is impossible to avoid sharks once they turn up, attracted by berley in the water or the struggles of hooked fish. The only solution is to up-anchor and move; or put out a bait on a wire trace and a heavy outfit and catch the shark. But galvanised shark hooks should be used, not stainless steel, so if the shark breaks the line the hook will soon rust out.

Bite times
Bite times are 4.10am and 4.35pm tomorrow and 5am and 5.25pm on Sunday. More fishing action can be found at GTTackle.co.nz.