The main differences between a closed estuary and an open estuary are that:
1) there is no tidal influence in a closed system;
2) there is little or no current in a closed system;
3) the water temperature is directly linked to atmospheric temperature;
4) fish are trapped in a closed system and cannot go out to sea.
Most fish species anglers are interested in catching in an estuarine system are, in fact, marine species that use the estuary either for feeding or as a nursery area. These species need to go out to sea to spawn, so when they are trapped within a closed river system they cannot reproduce. They can, however, continue to grow and to thrive, as long as conditions such as salinity, temperature and food supplies remain within their survivable limits. This means that as long as fish are not being removed from a closed system in great numbers there will always be fish in them, and they are getting bigger each year that the river is closed.
Using artificial lures in a closed system is a bit trickier than in a tidal estuary, the main reason being that, without the tidal influence and current, it is often more difficult to predict where the fish will be. The fish are not concentrated in numbers in certain areas as they would be in a tidal system during tidal events. This also means that there is not as much aggression in their feeding, due to the fact that as they are not in any great concentrations, there is little or no competition factor amongst the predators.
With the fishing being basically stillwater fishing, lure choice becomes more critical. Slower moving lures that give off plenty of vibration or movement without needing to be retrieved fast are ideal. Some lures that are difficult to use in current are excellent in the still waters of a blind river. There is more finesse required when fishing the still waters of a blind river, and plenty of patience and perseverance. A good approach when fishing blind rivers is to set up one rod with a live mullet on a circle hook and a float or sinker, and then work the area with lures while you wait for your mullet to get picked up.
I recently did a trip to Kleinemonde in the Eastern Cape, where I was privileged to fish with Dr Paul Cowley, principal aquatic biologist at the South African Institute for Aquatic Biodiversity (SAIAB), who lives in Kleinemonde. Paul is conducting research on the biology, ecology and movement of coastal fishes in the area. He knows the area very well, as it is his own backyard as well as his area of expertise, and I was able to learn a lot from him in our few days of fishing together. The East Kleinemonde River was open to the sea, having recently opened due to the high local rainfall, while the West Kleinemonde River, just a few hundred metres away, remained closed. We spent a bit of time fishing both rivers, but concentrated most of our efforts on the closed West Kleinemonde River, where Paul assured me there were some very decent kob and garrick trapped within the system.
Paul Cowleys son, Lloyd, did however catch a lovely garrick in the East Kleinemonde River on a spoon, which gave him a great fight on the light tackle that he was using. The fish weighed around 4kg and already had a tag in it, so it was a recapture.
This incident highlighted a couple of things for me. Firstly, the fact that estuaries are a really great place for young anglers, as they are a safe environment, with easy access to fish. Secondly, the fact that if the angler that originally caught that fish had kept it, Lloyd would not have caught it again.
So the bottom line is, one fish can make the day for a few angler during its lifetime if it is correctly handled and released back into the system.
Fishing the West Kleinemonde River proved to be quite challenging initially. The weather was not playing the game, with strong westerly winds, a cold front and squalls of rain about. The fish seemed to be affected by the conditions, and despite our best efforts at casting a variety of lures the first day didnt provide us with a single fish. Conditions did improve after that, though, and the fishing got better.
With the conditions still being fairly marginal, we had no success at all on surface lures, but managed at first to pick up a few nice garrick on live mullet. The mullet had been caught with a cast net, rigged with a single circle hook and fished with a float, to stop them getting tangled up in the weed beds. The circle hook had a small j-hook wired to it to act as a sort of offset bridle rig (see illustration at right).
When the garrick approached the live bait, the mullet would begin to panic, pulling the float down and swimming erratically. The garrick would then grab the mullet and we would let it swim with it for around fifteen or twenty seconds, giving it plenty of time to eat the mullet while the reel was on free spool. Then we would click over the bail and wind the line up tight, not striking. This would generally set the hook and the fight would be on. I must point out here that this system was not totally infallible and we did miss some fish as well.
The garrick that were caught were generally between eight and ten kilograms, giving a great fight on the light tackle that we were using, and all were in excellent condition. It was clear that they had not suffered any loss of condition due to their being trapped within the river. Paul tagged all of the garrick in order to hopefully get information later about where these fish moved to after the river opened up and they were able to go back out to sea.
We started to have some action on the lures at around sunset the one afternoon. We had been spinning with 12cm Rapala Glidin Raps, which are absolutely ideal for using in blind rivers for kob and garrick. They swim at a depth of between 1.5m and 60cm with a nice slow gliding, side-to-side action, hanging suspended between twitches. This lure is deep bodied, and looks a lot like a Rapala Super Shad Rap without a lip. Paul got the first fish, a beautiful kob of around 15kg, which inhaled his Glidin Rap only a few metres short of the bank. A few minutes later he got another kob of around 12kg on the same lure. It got too dark just after that, and we had to head for home and dinner, but we were hopeful for the next morning.
The following morning we were on the water at first light and picked up where we had left off. I got a nice kob on my spinning outfit, also on a Glidin Rap, which took off like a steam train. At first I thought that it was a garrick, but then it came to the surface and shook its head, trying to get rid of the lure in its mouth and I saw the distinctive kob head. Paul then got another lovely fish on his lure, which was starting to look like it had been chewed up by a staffie pup. These were all very decent fish, and would have made anyones day fishing in the surf on heavy tackle, never mind sitting on the bank of a little blind river with light spinning gear! Sadly, we had to head home after that session, but it had been an awesome morning, with some world-class fishing.
Within a week of arriving home after the trip, Paul phoned me to tell me that the West Kleinemond River had broken open to the sea. All the fish that we had caught were now able to leave the river and join in with the other adult fish out there to spawn and pass their genes on to new generations. It was great news to me, and I found myself wishing them luck and hoping that they get the opportunity to make lots of babies.
The tackle that we used for fishing the rivers in Kleinemonde was:
rods: Shimano Trevala 66 Medium Heavy
reels: Shimano Sustain 4000
line: Sufix 832 20lb braid, 30lb Sufix Zippy leader
hooks for livebait: VMC Tournament Circle 6/0
lures: Rapala Glidin Rap 12cm. <CLOSE BOX>
For anybody interested in the ecology of blind rivers, SAIAB has produced a really interesting booklet that they are happy to send free of charge to anybody who wants one, including postage. You can contact them via their website: www.saiab.ac.za, phone them on 046 603 5800 or write to them at Private Bag 1015, Grahamstown 6140, and they will send you a copy.