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Japweed!

I wrote this piece when invasive seaweed was a big issue - some years ago. These days japweed is a feature of many rocky shorelines. I was reminded of past experiences when I caught a bass recently after the plug had become tangled in weeds:-

MOST anglers would be very pleased to have a set of detailed maps of the ground underlying their favourite waters. Boat anglers invest in sophisticated echo-sounders and Decca equipment to get those vital facts about the hidden sea-bed --- information which will guarantee the presence of fish beneath the boat.

Sea-shore fanatics, like myself have “got it made” because every day, without fail, our fishing grounds are revealed to us by the falling tide. Every pebble-boulder and patch of sand is revealed for anyone to see and to note for future reference. Not only do we have a detailed plan of every mark but, for the rock angler at least, the depth contours are clearly indicated.

The striking zonation of the life on every shore is a result of gradients - exposure to light, air and water, wave action and interactions between plants and animals. Barnacles, winkles, limpets and, above all, sea weeds reveal, in graphic form, the levels of every ridge and gully.

On the more exposed rock surfaces some of the less-tough weeds may be absent but, in general, as the tide falls, barnacles, channeled wrack, bladder wrack, serrated wrack and kelp will each be revealed in turn. So, how can this miserable botany lesson be of interest to the sea angler? Can it help you to catch more fish? Surprisingly the answer is that it certainly can.

It should be second nature to every keen “rock hopper” to note the level of the sea surface every time he has a bite or catches a fish. In this way it is possible to build up a dossier for every mark which will indicate, for each phase of the tide and for each set of weather conditions, when fish are to be expected.

As the last strap of kelp disappears beneath the waves the bass may swim up to forage over a rocky ledge; this will be when your plug/sandeel/crab is seized with the thrilling and purposeful lunge that signals the species.

The bladder wrack is just beginning to break the calm, oily surface of the summer sea and past experience tells you that the great red-bronze wrasse will be shouldering their way through the fronds as they make their way back to deeper water. A floated live prawn or a buoyant, squat lobster-style lure, fished amid the fronds, may make a fish hesitate for long enough to sample the bait in its massive rubber lips.

If the patterns of conditions and catches are repeated on several occasions it often becomes possible to predict which fishing spots are best for any state of the tide. In this way, by shifting from one spot to another as the tide rises and falls, it is then possible to make the most of every fishing trip.

More familiar to most sea anglers is the nuisance value of sea weeds. The inch thick kelp stems in which every other set of tackle seems to become entangled; claw like hold fasts with a limitless capacity for absorbing 4/0 hooks, the string of leathery ”flags” flying up the line and gathering in bunches at the rod tip and the heavy “conger bite” which resolves itself in to a dragging mass of thongs twisted in to a ball of knitting included the lead, swivel and hooks.

Some of my toughest battles have been fought with loose weed in the strong undertow of a heavy surf! One seaweed problem is of fairly recent origin. When my sons first began sea fishing in the late nineteen-sixties ‘Japweed’ was unknown in this country. Sargassum muticum is a relative of the Sargassum which floats perpetually in the great circulation of the Sargasso Sea. ‘Japweed’ resembles enormous, brown, branching boot laces. Scattered along the fronds are many small air bladders which support the plant as it reaches up towards the well-lit surface of the sea.

A Pacific Ocean species, ‘Japweed’ is believed to have been introduced to British waters with imported Japanese oysters, possibly via French oyster beds. The original report of this plant was from Bembridge in the Isle of Wight in 1973. The subsequent spread of plants, along both sides of the English Channel has been carefully recorded by scientists from Portsmouth polytechnic.

In 1976 the first reports were received from localities beyond the Solent when plants were found in Chapmans Pool in Dorset and at the mouth of the River Yealm, in Devon. Attached (growing ) plants have now been found as far afield as Sheringham in Norfolk to the east and the River Yealm to the west (now, no doubt, much further).

In sheltered situations, which are never exposed to the air at low tide, the plant flourishes. Despite attempts to weed out and remove plants in the early seventies (attempts which were doomed to failure as I shall explain). Sargassum is now well established at many suitable sites, notably around the original I.O.W locations and in the Fleet, near Portland, Dorset.

There are several reasons for the success and rapid spread of ‘Japweed’. Like many other sea weeds Sargassum produces millions of tiny drifting ‘spores’, each of which is quite capable of growing in to a new plant. This species is self fertile, so only a single mature plant is needed to produce ‘spores’. To make matters worse the mature plants may shed branches which, because they are well endowed with air bladders, will drift away on the currents spreading the spores far and wide.

“So what’s wrong with a bit more sea weed?” I can almost here the words from the more northern weed free exponents of the gentle art. “We are already up to our eyeballs in weed, so who cares about a spot of foreign “Fucus”. These comments should be addressed to those of us who have had fishing trips spoiled by massive floating mats of Sargassum; to those whose favourite bass marks have been rendered totally unfishable by dense ‘meadows’ of standing weed and to others of us who have spent hours unwrapping the prop shaft of the dinghy from the complicated, clinging, tangling strands.

There is no doubt that Sargassum muticum is a problem that will face many more sea anglers in the future. Numerous places along the South Coast and in the Channel Islands are quite suitable for colonisation of this plant. Eventually it may “settle in “ and be accepted as one of the normal hazards of sea angling (I think it now has) but, before the time comes, we shall all hear more of this seaweed.

As a closing comment, I would like to put forward a possible brighter side to this alien element of our seaweed flora. The massive, thickly-branching strands of ‘Japweed’ must provide a fine shelter for the young stages of at least some fish. Even those areas where angling is prevented by the presence of dense weed growth may not be ‘all bad’, acting as refuges for bass, wrasse, pollack and other shore hunting species of interest to sea anglers. In addition the remains of 'Japweed' cast up along the shore adds to the food resource for the maggots, hoppers and wood lice that are so important as food for many fish.

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

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