Thats a horse of a slimey, would be  a perfect  livey, couldn't  see it lasting long when the kings or Mr stick face turned up. Spent many hours wishing I had a couple that size in my live bait/rock pool.

Lots of clean water with plenty of oxygen and there are happy as, try not to handle them and yeah they don't like the sun, but if you look after them they will stay alive for ages especially if you bridle them.

We were stocking up on baitfish off the wharf at Ruffins bay,Coro, 2 weekends back.

Are they still in inner gulf. Last autumn snapper fishing and with a line out for small jack macks caught what looked like jack macks ,but were a bit larger 30-35 cm, but were somehow different. slightly different shape, a bit more colour. They were somehow different. Wondered if they were Koheru. This in rangi channel area.

 My experience of Koheru is that the change of light is a good time off rocky points. They can be attracted with a fine berley and I've caught then on a very small silver jig, a few metres below the boat. Not the easiest fish to find and catch.
They are chunky, fiesty little fish that really fight hard on light tackle.
Jack macks and blue macs often school together.
Never eaten a koheru but other fish seem to like them. Have been too valuable as marlin/kingie livies to eat.
Blue mackerel, especially the 200 mm size are great eating. Have seen the bigger 1.5 kg ones selling for $12/kg in supermarkets. Blues make better cut baits than Jacks.
Jack macs are NZ's biggest export fish selling thousands of tonnes to middle east.
I have seen more jack macs in a marlin's stomach than any other food - saw about 20 inside one marlin off West coast and seen a couple of jack mac bait balls with numerous marlin in attendance. Almost every Koheru used as a marlin livie has scored.

Greg at Gofish hit a big school at the Noises last year recall him telling me

Had heaps out at the Chicks a few weeks ago and prior to that. Heaps of them and up to 40cm. Entertaining on light gear. Got some Kingies on them, kept a few to freeze and did some as sushi-mi -  Bloody excellent

Only places I've seen them consistently is the mokes and karewa island. Never seen one landbased