Middle Harbour differs from most other estuaries and rivers in that it is a flooded valley.

Unlike the Hawkesbury, for example, whose path was cut by running water falling off a huge catchment area, the Middle Harbour valley simply filled up when sea levels rose at the end of the last ice age.

In a way, it is a lot like an impoundment in that it is very deep and the main features are the old creek bed and all the landform features that made up the original valley when it was dry.

Because of the tiny catchment salinity levels are similar to those along the coast and at its deepest point it reaches 37 metres. You need to go half a kilometre off Sydney Heads to find that depth.

As a result, Middle Harbour offers a perfect environment for big fish and oceanic species that would otherwise find a classic river or estuary environment quite unsuitable.

Dolphins come in, as do big sharks. A three-metre bull shark was netted by fishermen at Grotto Point in 1999 in only two metres of water and I have no doubt that it was either on its way up or back out of Middle Harbour.

Six fatalities have occurred in Middle Harbour, four well upstream near Sugarloaf Bay and two in the shallows near Balmoral. This makes Middle Harbour the shark fatality capital of Australia.

The only obstacle to very regular visits from big oceanic fish is the shallows of Hunter Bay at the mouth of Middle Harbour. The deepest channel through here is only three metres at best but this hasn’t stopped big blue groper, jewfish, kingfish, northern bluefin and yellowfin tuna, spotted mackerel and cobia from making the trip upstream in previous years.

Hump-headed snapper were regulars in past years and we still get bonito, salmon, frigate mackerel and spangled emperor regularly enough to make them worth targeting.

To give you a clear example of the uniqueness of this situation, a few years back anglers were battling northern bluefin tuna only 100 metres from the mangrove flats where they had been catching bream and whiting on only an hour earlier .

Right up the back of Middle Harbour you find intermittent fresh water – just enough though to support a few estuary perch. I’ve heard rumours of bass but I’ve never seen one in the flesh and I’m guessing that they were probably misidentified perch, although there are bass found in other Harbour tributaries so I suppose it’s possible.

The reason for this quick run-down on Middle Harbour is that it is firing at the moment and the highlight has been Peter Kelly’s 11.3kg cobia taken in Sugarloaf Bay. Fishabout Tours Guide Mick Collins had the boys on a hot kingie bite when the cobia appeared behind a hooked fish. For the next half-hour they tried everything until finally it took a fresh squid strip.

On other fronts, jewfish have been reasonably common with the best of them coming from The Spit and Pickering Point. They have all been daytime fish and mostly taken on fresh squid.

There have been plenty of kings through Middle Harbour, mostly in the stretch between Sugarloaf and Bantry Bay and have been exhibiting a preference for – you guessed it – fresh squid.

On the surface there are bonito, salmon and big tailor around Sugarloaf taking trolled minnows or cast Raiders.

The main Harbour has been invaded by plagues of frigate mackerel. They will respond to high-speed 10g Raiders, as will the toothy long tom that are feeding alongside them.

Washaway Beach fished well after a cloud of anchovies moved in. Salmon, tailor, bonito and Watson’s leaping bonito were hammering them in the wave line so fish your Raiders right up in the suds.

It’s also worth bouncing a softie through the bait clouds as there have been some good flatties sitting under the anchovies.

1

Peter Kelly’s 11.3kg cobia turned up in the middle of a hot Middle Harbour kingfish bite and eventually took a squid strip.

2

Kingfish can stack up in droves in the depths of Middle Harbour at times.

3

Solid school jew add to the huge variety of fish that inhabit Middle Harbour.