Catch fish with Mike Ladle.

Catch Fish with
Mike Ladle

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SEA FISHING

19 November 2002

A spot of science.

I have hardly set foot out of the door in the past week so - no fish to report. In truth I tried bait fishing after dark down at the coast. Nothing of any size touched my big squid baits. I also went to some local ponds where I have been catching carp this summer. I took a spinning rod, a mullet spoon and a few earthworms in the hope of catching perch - total failure. In fact the only evidence I have that there are any perch present is a chap who told me that he had caught one on sweet corn a couple of months back. The water was pretty murky due to the activity of carp and bream so not ideal for spinning in any case. I'll try again if the water clears a bit.

Anyway, with the proposed ban on cod fishing in prospect I thought that you might like a bit of semi-scientific information for a change.

Firstly, is it true what the scientists are saying about the decline in fish stocks? Well every sea angler has his or her own ideas about such matters and these ideas are largely coloured by their recent experiences. If you have been catching plenty of cod you may think that there is no problem. On the other hand if times have been lean you may be all for a ban on commercial fishing. Of course neither of these views is very rational. You really need to know not only how many fish are out there but also how big they are and these facts vary with the species concerned and lots of other factors.

Some of the best clues about how fish respond to commercial fishing pressure were gathered during periods of war. For example many fish stocks, around our shores, which had been overfished were suddenly left alone when fishing stopped during the First World War (1914-1918). After the war commercial fishing started up again ad once more stocks diminished and fish sizes decreased. This was a century ago so just imagine what modern ships armed with modern position finders, echo sounders, nylon nets, powerful engines and so on have done.

Flatfish suffered in just the same way as cod. Dabs, which were mostly four or five years old in 1919, were almost entirely two year olds after twenty years of exploitation. Just another flatfish snippet. A plaice is a plaice but, amazingly, the North Sea plaice stock were quicker growers than the Baltic fish - even after they had been tagged and transplanted to the Baltic.

Secondly, a lot of people feel that they have a better chance of catching fish, from the shore, on the spring tides. All sorts of reasons are put forward for this supposed improvement - more water movement, greater depth, different areas of beach covered by water etc. However, it seems likely that even if these are valid reasons, the fish are there because more food is available. One of the main differences which could explain this sort of thing is patterns of change in 'night tidal plankton'.

If you go down to any sandy beach, take a shovel full of sand and wash it gently through a fine sieve, you are sure to come across lots of little worms, clams and shrimp-like creatures. The shrimpy things are mostly beach fleas or sand hoppers of various kinds and they may be present in huge numbers. Normally these little crustaceans stay well buried in the sand but after dark on the bigger tides the males come out and swim round, looking for mates, in and around the surf line along the waters edge. At these times flatfish, bass, whiting and other shallow species come in to feed on them. A look at the graph below will show just how striking this pattern of activity is.

Since I wrote this I've actually caught a few fish so I'll put some real fishing on next week.

If you have any comments or questions about fish, methods, tactics or 'what have you.'get in touch with me by sending an E-MAIL to - docladle@hotmail.com

Fish stocks.

When fishing effort is reduced (as during wartime) fish stocks rocket.

The average size of cod.

After the war cod were much bigger and averaged almost a metre in length.

Transferred plaice.

North Sea plaice transplanted to the sea off Denmark (red line) grew much quicker than resident plaice (blue line)

North Sea dabs.

In 1919, after the war, dabs were BIG but with continued fishing pressure they got smaller and smaller.

Fish food and spring tides.

Sand hoppers are just one of the creatures that swim in the surf during spring tides.