The Environmental Effects of Marine Fisheries

The Environmental Effects of Marine Fisheries

The Royal Society of Edinburgh (RSE) is pleased to respond to the Royal Commission on Environmental Pollution’s study on the environmental effects of marine fisheries. The RSE is Scotland’s premier Learned Society, comprising Fellows elected on the basis of their distinction, from the full range of academic disciplines, and from industry, commerce and the professions. This response has been compiled by the General Secretary, Professor Andrew Miller and the Research Officer, Dr Marc Rands, with the assistance of a number of Fellows with direct experience of marine and environmental issues.

The Society welcomes the decision by the Royal Commission to address this issue. As noted in the consultation paper, the fisheries industry is international in nature and therefore setting these issues in a global context will be important. For example, what goes on in neighbouring waters, such as Norwegian and Icelandic in particular, is inextricable from what goes on in EU waters.

The problem of environmental effects of marine fisheries has also to be viewed in the context of historical over-exploitation and long-term environmental change, whether naturally or anthropogenically driven. The marine environment can be highly dynamic and, in large parts, it could be difficult to say that the current altered structure of the ecosystem is more desirable than a structure that is closer to the pristine state. This is because there are few real reference points as to what a pristine state should be. It is often easier to define what specific effects of marine fisheries are not desirable rather than to define an environmental state towards which the ecosystem should be managed.

The problem at the root of how the environmental effects of marine fisheries are managed comes in the mismatch between the way the products from fisheries are valued and the way the environment is valued. So long as the currencies involved in these two valuation processes differ then the perception still around today, that the marine fish resources are "free", will mean that there can never be a sensible evaluation of the costs and benefits of marine fisheries to society. The system of subsidy which is also applied to many marine fisheries causes a dangerous skew in this evaluation process. There is, therefore, a need to understand the comparative economics of marine fisheries and conservation.

The specific issues identified for consideration are addressed below:

Developing more appropriate management measures for aquaculture to avoid problems of pollution, disease and the introduction of alien species

In Scotland, aquaculture contributes 40% of all agricultural exports, worth £310M at farm gate and over £600M as processed product. As such it is larger than sheep or cattle production and dwarfs fishing per se. The scale and importance of aquaculture in comparison to the inevitable shrinkage of the fishing industry makes it a major economic engine in rural communities. There are, however, concerns over the growing environmental effects of this industry. In this context there are current on-going inquiries into a strategy for aquaculture by the Scottish Executive Environment and Rural Affairs Department (Contact: Graham Thompson) and the Scottish Parliament Transport and Environment Committee (Contact: Tracey Hawe).

Global capture fisheries are finite and traditional capture food species (e.g. gadoid white fish and flatfish) are currently in decline. In particular, several important species of wild fish stocks in the North Sea, such as cod, are in danger of collapse. Landings of wild fish species in the UK have decreased and been replaced by imported fish and local aquaculture production (primarily of salmon and trout). There is also the potential in Scotland for the aquaculture production of species such as cod, haddock and a variety of flatfish.

There is a need to develop new fish feeds containing oils and proteins derived from vegetable and/or cultured algal and fungal sources rather than from wild-caught fish species. In this respect, an EU-funded research programme coordinated by the Institute of Aquaculture at the University of Stirling is currently investigating the genetic basis of the ability to produce long chain omega-3 and omega-6 fatty acids from shorter chain precursors in fish. This could lead to the selection of broodstock more capable of converting less beneficial plant oils to more desirable fish oils. In the mean time, a key element of future policy should be the use of "discards" and "black fish" from traditional capture fisheries, following the lead set by the Icelandic authorities. Trawling is a very wasteful process that has little selectivity. A very substantial 'by-catch ' (of invertebrate animals and small fish) is obtained and much, if not all, will be thrown back and a considerable proportion will die. Much of this could be put to better use as a primary source of fish-meal. It is also desirable to remove the current excessive, and nutritionally unsatisfactory, dependence of marine fish larval production on brine shrimp (Artemia) eggs by developing larval feeds based on marine primary and secondary production, for example by developing efficient algal and zooplankton culture.

Given improvements in fish feeds and disease control, further growth of the industry is possible. At present, trawling for wild fish stock is having a serious environmental impact on the marine environment, with large tracts of the seabed being churned by trawls, destroying the benthos. Exploiting aquaculture technology could assist the recovery of currently endangered stocks, molluscs and crustaceans as well as finfish. Sensitivity in marine farm site selection, with more offshore locations and the rotation of production could minimise the benthic impact and allow the seabed under fish farms to recover relatively quickly. The breeding of juveniles of species that can be released into the sea for the benefit of the wild fishery (e.g. lobsters and crabs), are also worthy of continued investigation. In this context, there is a serious concern over the depletion of stocks of juvenile tuna that are being caught in large quantities for on-growing in cages

Improvements in impact of existing sites can also be achieved through the effective use of fallowing. In some cases, the provision of extra sites would allow existing production to be maintained, but at the same time reduce overall environmental impact. In addition, environmental impacts can be reduced by improved control of diseases in crowded monoculture conditions through the increased application of the National Treatment Strategy for the control of Sea Lice and the increased use of vaccines. In addition, improvements could be made in feed digestibility and reducing waste production. Further research should also be undertaken on interactions between escaped fish farmed salmon and wild fish stocks.

Addressing the particular vulnerability of deep-sea species

It will be important to establish a proper scientific, cultural, administrative and social framework that will address the generic problems that are highlighted by the exploitation of deep-sea species or the risks to coral communities. Providing local solutions through a raft of specific legislation or regulation will not protect against the unforeseen problems of the future. Generic solutions are required.

Many deep-sea species of fish are particularly vulnerable to exploitation and some species may be genuinely in danger of extinction. This contrast with most fish species elsewhere where we often refer to extinction of the fishery but this does not necessarily imply extinction of the species themselves. The vulnerability of deep-sea fish arises because they can been very long-lived with low potential rates of replacement and, at some times, they can congregate in a way that makes them very vulnerable to capture in fishing gear. Added to this, they are often found in international waters, which complicates the process of regulation. The problem of regulation is not unique to that of deep-sea fish but more could probably be done to tackle the problem through regulation of the markets (rather than the fishing vessels) at the port of landing and elsewhere.

The problem of the recent development of deep-sea fisheries illustrates a general problem with the way that fishing is managed globally. New fisheries can be developed at a faster rate than information is obtained to provide a basis for a sensible policy of regulation. In the case of some deep-sea species, by the time a problem has been identified it may already be too late to introduce regulation. There is a need for precautionary regulation.

Considering the risks posed by fisheries to certain ecosystems and habitats, for example, seamounts, hydrothermal vents, sponge associations and deep-water coral communities
An ecosystem approach to the management of marine resources is a positive way forward. This approach provides for effects of fishing beyond the exploited species and attempts to reduce potential impacts on the structure and function of the ecosystem as a whole. At present, few if any feasible implementation scenarios have been developed for ecosystem approaches to the management of marine fisheries. The most common approach being developed in several arenas is through the use of indicator species. These species may not be exploited species in the ecosystem but they have several characteristics that make them reasonable indicators of ecosystem status. In some cases these species are formally included as an explicit component of ecosystem management structures, such as in the Convention for the Conservation of Antarctic Marine Living Resources, but more often they have been cases where public opinion has resulted in these species being developed as specific indicators of ecosystem quality. An example of this comes from the Bering Sea and Gulf of Alaska where the Steller sea lion is being used as an indicator species mainly by virtue of its legally protected status and because conservation groups are using it as a benchmark to press their case for adverse effects of marine fisheries.

Given the practical difficulties with understanding the dynamics of marine ecosystems, using benchmark levels of indicator species populations may be one of the most feasible methods of future management. Such species need to have a range of characteristics such as:

i. Visibility; i.e. it is relatively easy to gather data about their populations, movements and interactions with other species;
ii. Importance; i.e. they form a major component of the trophic structure;
iii. Responsive; i.e. specific characteristics of the species, such as behaviour or population levels need to be responsive to changes in the environment and these need to be understood in terms of the spatial and temporal resolutions they represent.
iv. Valuable; i.e. it is helpful if they are seen by the public as valued components of the ecosystem.

In many ways, these indicator species of the marine environment are best characterised by the species at the upper end of the trophic structure. This is because they are down-stream of the main energy (and pollutant) flows within the ecosystem and are, therefore, most likely to integrate a response over wide spatial and temporal scales. Most of these species are represented by seabirds, seals, cetaceans and some of the larger predatory fish and sharks. Establishing threshold or target characteristics for the populations of these species will likely ensure that the ecosystem structure that underpins their existence is well-founded.

Exploring the adverse environmental impacts of certain fishing gear, especially those leading to excessive catches of non-target organisms and habitat disturbance

The marine environment is a complex place that is difficult to observe. New technology is only partly capable to solving the problems of data acquisition and the costs of data acquisition are likely to increase. Knowledge of the structure and dynamics of marine fish populations, the primary target for fisheries, is poor. Knowledge of the secondary effects of fishing on non-target species, either through bycatch, because of food-chain cascades or because of damage to habitat by fishing gear, is even less well known. The complexity of marine food chains is enormous and our future capacity to model and forecast the effects of fishing in one part of the food chain is strictly limited. Although the development of models of marine ecosystem dynamics is an active area of research, there seems little prospect of this providing a useful management tool in the foreseeable future.

Considering the benefits for the marine environment of the temporary or permanent closure or other protection of certain areas

As the Commission's letter indicates, political and public opinion is now considerably more open to the idea of protected areas. In this context, the Green Paper on the Future of the Common Fisheries Policy, produced last year by the European Commission will be a useful reference for the Commission's deliberations. Protected areas have also feature strongly in the 2002 Conference on Sustainable Development in Johannesburg.

Additional Information

In responding to this consultation the Society would like to draw attention to the following Royal Society of Edinburgh responses which are of relevance to this subject: The EU policy on Biodiversity (May 1999); Conservation of Salmon and Sea Trout (August 2000); Protecting and Promoting Scotland's Freshwater Fish and Fisheries (August 2000); Sixth Environmental Action Programme (May 2001); The Nature of Scotland (June 2001); The Future of the Common Fisheries Policy (June 2001); Scotland’s freshwater fish and fisheries: Securing their future (November 2001); A Strategy for Aquaculture (April 2002) and The Scientific Issues Surrounding the Control of Infectious Salmon Anaemia (ISA) in Scotland (June 2002).


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