6) Within the North West of England, the flat sands and shallow waters allow the use of a Wet Dredge under experimental authorisation. The principle is similar to the tractor dredge, but the discarded cockle appears to survive better following sorting by a gentle jet of water sprayed at a fixed (rather than rotating) screen. Wet Dredging
7) Hand Gathering Fisheries. Elsewhere in the UK, including the main cockle areas in South Wales (ie. Burry Inlet and Three Rivers estuaries), hand gathering is the only method allowed. Here, gathering is restricted to hand rake and riddle, to a 19mm (square) minimum size with no fishing allowed to take place at night. Map : Burry Inlet & 3 Rivers estuaries Hand gathering has been undertaken in the same way since the 1800s and is, in the 1990s, largely unchanged. Picture : Hand Gathering in Burry Inlet – Past
and Present
The most significant development over the years has been the change from donkeys as a mode of transport which limited catches ashore, to horse and cart (allowing larger loads) to Land Rover / tractor, but not until 1987. Women used to be in the majority until the cart allowed more cockles to be physically gathered. It is a labour intensive, back breaking job. 8) Burry Inlet fishery Landings are fairly consistent between the range 1,000 to 5,000 tonnes per year. The large catch in 2000 represents a heavy and widespread settlement, followed in 2001 by a spat (settlement) failure. Biotoxin induced fishery closures and other issues have reduced landings in 2003 and 2004. (see below)
Management is by way of a ‘Regulating Order’which
allows the SWSFC (as grantee) to additionally limit the number
of licence issued, and apply a daily quota of 250-500 kg
and prevent Sunday gathering. Some 50-55 licences are
issued annually, although occasional temporary licences are
also issued. The latter are drawn from a waiting list
(which stands at c155 persons) in strict chronological order
of application. A licence fee of £648 per year
applies and must, according to the Act, be spent on the fishery
itself. 9)The Burry Inlet fishery has been recognised by a Marine Stewardship Council accreditation, the only Molluscan fishery in the world so far to receive such an accolade. Independent certifiers have found that its management gives rise to a sustainable fishery in both fishery and ecological terms which reflects social good practices. Accredited suppliers can use the logo on their cockle products; and the consumer may choose to buy these over any other produce with a clear conscience. The Burry Inlet is also a Special Area of Conservation (SAC) and Special Protection Area (SPA) for Birds. Such designations increasingly require a higher standard of environmental management than other sites and are set to challenge fishery managers even further in the future (see below). 10)Three Rivers Estuary
Cockle landings in the neighbouring Three Rivers estuary are altogether more variable than the Burry Inlet, ranging from 0 to ca. 5000 tonnes in 1993.
The estuary has a greater exposure to waves, and although cockles spawn and settle regularly, in most years they are washed away. The exception being the arm of the estuary at Laugharne which lies within a MoD firing range. Even here changes to the river channel have vary the size of cockle habitat. Stock management is via the standard minimum size, hand only gathering, and no night fishing. In 1993 the so-called ‘cockle wars’ saw fighting between rival local and ‘immigrant’ gangs from England. Since then, in 1998 a permit (available upon request) require fishers to provide an ID, National Insurance number and photograph, and is the means by which catch returns are collected from named individuals. Permits are available to everyone free of charge, reflecting the limit of current Sea Fishery Committee powers under byelaw. This contrasts to the Regulating Order powers in the Burry Inlet, which allows the Committee to restrict access by means of a chargeable licence and to recover, in full, the costs of management. In order to both limit footfall and limit the effect of the large numbers of gatherers on the rural community (up to 2,000 people on ‘opening day’) daily fishing is rotated between beds and days; those at Laugharne opening on weekends only when the MoD are not firing! Picture – Hand gathering at Ferryside.
It is noteworthy that once cockle beds are closed to prevent cockle depletion, significant pressure is placed upon the regulators to re-open the beds once stocks recover. “D-day” for opening is widely anticipated by all who might wish to gather cockles, and feared by the local Community who find themselves inadvertently involved. The permit system is onerous to administer, but has made people more accountable and tends to discourage those seeking to defraud Inland Revenue or Benefits Agency. However, its merit as a fishery management tool, are limited. It begs the question, as to what extent fishery managers ought to manage fisheries directly or primarily for social reasons even if they had the legal powers to do so? The photograph of large numbers of individuals’ hand gathering cockles might equally have been taken at Morecambe Bay in 2004, where similar ‘social’ questions are being asked, albeit in (sadly) very different circumstances. The “Open access” hand-gathering fishery scores lowly on fishery effort control and accountability. However, it is arguable that it is cheap to run and as the benefits are shared more widely, it offers value for money and equity. Balancing this would be the extent of “co-lateral damage”, through people pressure on community interests, cockles trampled in the sand and of a need to concentrate management resources at one point in time and on “crowd “ control.
As a rule of thumb the taking of a third of the biomass of adult standing stock each year has proved its worth in the Burry Inlet as a stock conservation rule, and is now being applied to other fisheries. ie 33% to the fishermen ( it Total Allowable Catch – TAC) 33% for bird food, and the remaining 33% to act as brood stock in order to sustain the fishery. Annual landings can be limited through licence number, quota, or open / closed season to determine fishing days depending upon the fishery management powers available. Given good survey data, we know what can be taken, and what cockles must be left for the birds and to sustain a spawning stock; but what are the other considerations? Taking 33% of what exactly? Clearly the cockle stocks are dynamic with numbers and biomass continually change e.g. through growth (especially in the summer) and losses (especially due to storms or excessive heat etc). In particular, cockle growth is itself dependent upon a number of factors including: cockle density (food sharing), age (smaller cockles grow faster), food availability, cockle metabolism (depends on water temperature) and emersion time (tide coverage dictates cockle feeding time).Growth is negligible in the winter (which creates the growth “check” on the shell), and poor in the spring particularly after spawning. During the course of the year all cockles grow significantly, both in shell size (by the end of the year) and in meat yield (higher in summer than winter, but poor during spring spawning). These factors themselves create very large changes in cockle biomass and thus fishery value. It is usual that fishery managers make estimates of biomass in the late spring before fishing starts. Increasingly, fishery managers are starting to consider the use of models with locally derived data to make judgements on growth and mortality to more accurately establish Total Allowable Catch (TAC). In practice therefore, after bird predation, natural mortality and death by old age is taken into consideration, the fishermen are allowed to take, in effect, what is left! Scope does exist for more “hands-on” management of cockle fisheries e.g. through the thinning of dense cockle beds and movement of cockles from areas of best settlement to areas of best growth – either by mechanical or manual means. So far, most of the industry in the UK is very reticent to apply such measures, preferring to “harvest” rather than culture cockles. Other countries are far more advanced in this respect than UK industry and look upon our management with disdain and see wasted opportunity. Fishery managers themselves are too poorly resourced to move matters on – itself a manifestation of the current low standing of the Fishing industry within UK when compared to most other countries.
1. Nature Conservation Increasingly, fishery managers are now legally obliged to take account of the effects of fishing disturbance and catch depletion on the wider marine environment – particularly in sites designated for Nature Conservation purposes such as European Marine Sites (SACs & SPAs). The decline in landings in 2003 & 2004 for the Dutch Wadden Sea, referred to earlier, is a dramatic (if extreme) illustration of this. The resulting ECJ judgement has confirmed that fishing operations are to be considered as “plans of projects” just like any other kind of “development”. Previously, the act of fishing was considered as a necessary act of “management “. The effect of which is the requirement to pre-assess the anticipated level of fishing for potential impact upon designated site features and to grant fishing activity only where no significant effect can be demonstrated. Such burden has led to the prohibition of vessel suction dredging in the Wadden sea and subsequent fall in landings. All decisions will need to be backed, as far as possible, by sound science and biological information and, if absent; the precautionary principle will frequently need to be applied. Of course, this whole area is one where knowledge of baseline data and scientific understanding of cause and effect are not yet well established – a recipe for continual debate and delay between divergent vested interests! Gone are the days where (as in the 1970s in the Burry Inlet) oystercatchers were shot under government licence because cockles were scarce and the livelihoods of cockle licence holders were under threat ! Now it is more likely that the people would starve and, for example in Holland, more cockle reserves would be set-aside during hard winters to reflect the extra bird food needs. CCW & EN are commissioning models to describe bird food needs and food availability from various sources to try and inform such wider management decisions. 2. Wider environment. We believe that in addition to the natural variability of cockle numbers, the amount of food entering estuaries has decreased in recent years following the adoption in the UK of various EC Directives, especially those requiring, or giving effect to, the better treatment of sewage before its discharge to water-courses. Examples include : Bathing Waters Directive 76/160/EEC Shellfish Waters Directive 79/923/EEC Nitrates Directive 91/67/EEC Urban Waste Waters Directive 91/271/EEC Shellfish Directive (91/492/EEC) and UK Food Safety Regulations. And in the future – the Water Framework Directive 2000/60/EC In the Burry Inlet, for example, the growth of cockles has dramatically changed since 1994 as the graph below demonstrates (Data courtesy of CEFAS – Lowestoft):
Cockles which would have reached fishable size of 25mm between ages 2 & 3 years now take 3 to 4 years. This exposes them to one extra winter with concomitant increase in mortality. The period of most dramatic change broadly coincides with the addition of secondary and tertiary treatment on several major sewage works which discharge directly to the estuary or to rivers which enter the estuary. At the same time, merchants report a decline in Burry Inlet cockle meat quality. This has not yet been seen in cockles from the neighbouring 3 Rivers estuary. Such changes coincide with recent mild winters. Could it be that the cockles seek to feed at a time of the year when little food is available whereas in “normal” cold winters the cockles would be less active with reduced metabolism in the usual cold water? In addition, Burry Inlet sandbanks appear to have built up (perhaps due to increased storminess) thereby decreasing cockle emersion time. Furthermore, the estuary sides in some places appear to be infilling through mud accretion at the margins and the growth of Spartina grass. The whole effect of this is to reduce both the area available to cockles and tidal emersion time thus increasing the density of cockles and hence competition for (limited) food. The inevitable conclusion is that the available yield of cockles to commercial fisheries is therefore falling at a time when less fishing pressure is acceptable on Conservation grounds. 3. Recent cockle mortality events. During the summers of both 2003 and 2004 * an unusual die-off of cockle has been experienced. Summer temperatures were not exceptional and yet the effects have been both severe and unprecedented in the views of local commentators. (* See Postscript) During subsequent investigations, CEFAS scientists have found a high density of common cockle parasites; namely of Digenea flukes in the foot muscle and Nematopsis in the gills. They cannot categorically say that this is the cause of death since few samples have yet been taken and none before the event. Sampling therefore continues. It is probable that such parasites prevent the cockle from burrowing and make it more susceptible to predation and desiccation under the summer sun, thus increasing mortality. An increase in parasites might arise if the overall health of the cockle under current ambient conditions is poor thus impairing their ability to ‘fight off’ infection. CONCLUSIONS 1. The most difficult fisheries to manage are those that have (shell)fish and are successful ! Within which there is a need to take full account of environmental, social and economic considerations and make judgements so as to obtain a balance between often competing objectives. BUT :
Sea Fisheries Committees are increasingly required to take these decisions with decreasing resources (in real terms). Whilst they have always had direct powers to manage fisheries , and relatively new duties to mange the environment, their ability to take direct account of socio-economic aspects (eg. safety matters) is limited. 2. In reality, the fishery manager has little scope for active management. A proportion of cockles are set aside, and the industry (Fishing mortality) get what is left after the birds, natural events, death by old age, etc. 3. Improvements in water quality in estuaries might have gone too far to maximise the economic returns for cockle fisheries. Waters giving rise to a Public Health classification for cockles of “C” health grade waters appear to be the most productive, although in some cases “B” grade might suffice. Moreover, there is a suggestion from recent events in the Burry Inlet that cockle stocks are suffering and improvements in water quality are playing a part. It is ironic that some EC Directives that give rise to improvement in water quality might be directly at odds with those (like the Birds Directive 79/409/EEC & Habitats Directive 92/43/EEC) which aim to protect the natural environment. One thing is for certain in this modern world; when the there is conflict between protection of the environment or protection of cockle livelihoods, it is the latter that will suffer in the squeeze. P J Coates, Director May 2005 The views expressed in this paper are not necessarily those of the South Wales Sea Fisheries Committee. Postscript : July 2005. The prevailing cockle stock comprised a single year class from the 2004 settlement which was heavy and widespread, especially on the lower shores, amounting to some 8,700 tonnes over the enlarged survey area (CEFAS ; May 2005 survey). Over-winter losses were above average at between 60 and 90 %. Cockles lying in dense patches in dry sands on the upper reaches started to die-off during warm sunny periods in mid June. A period of prolonged hot weather in early July saw very significant mortality across all parts even on the lower shore, which was barely exposed to the sun. Die-off in dense aggregations was particularly rapid and severe. The extent of die-off will not be known until after the CEFAS annual survey in November, but would appear to be in excess of 90% of the original May stock. The causes of the die-off are not yet fully understood. Clearly the very hot weather has a major part to play. But cockles of a similar age and density in the neighbouring estuary have shown a far lower mortality. The early die-off, as in 2003 & 2004, indicates a particular vulnerability within Burry Inlet cockles to warm weather events as highlighted within the SAGB conference presentation. It is postulated that this sensitivity is related to cockle size (age) and cockle density and is possibly heightened by low oxygen conditions such as might be experienced during hot weather, and arising from the decay of cockle meats. However, unlike in 2003 and 2004 (and the last 6 years or so) cockle growth in the Burry Inlet in 2005 to July had been excellent with reversion to “normality”. This is despite the large cockle numbers and consequent heavy food demands. The reason for this change is not yet known. On the other hand, if cockles are again “fit and healthy”, why have they been so susceptible to heat stress loss? These and other issues, such as the role of parasites, presence of bacteria within cockles and local water quality issues will require to be investigated. Having now lost 4 good to very strong year classes of cockle over three successive years, the future of the Burry Inlet hand gathering cockle industry is in jeopardy and the participants will want to understand what has happened, and more importantly, how to avoid such circumstances in the future. If the conditions are here to stay, the industry will need to know how best to anticipate any events and minimise such economic losses. Furthermore, as cockles form an important source of food for birds, there are wider conservation implications. |
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The Common cockle (Cardium edule)
is well known. Found
on sandy / muddy beaches and estuaries at around mid tide
level, it is an easy species to study, and indeed to fish. You
can see them, count them, age and weigh them in order to
understand their population dynamics. They are ‘r’ selected
species meaning each cockle has the capability to produce
a large number of offspring.
