transboundary impacts caused by activities in the fisheries sector / transboundary environmental effects on fisheries / Summary

12.3 What are transboundary Aspects of Fisheries?--
A transboundary fishery resource is one for which activities in one country can have an impact on the same shared resource in another (and, usually, vice versa).

Not all fishery resources in the Mekong River Basin are shared.

For example, fish which migrate from one country to another are obviously a shared resource:

• because, if the fish are over-exploited in one country it will affect the abundance of the fish in the other country (or countries)

On the other hand, fish that reside within the boundaries of one country (e.g., within a reservoir, or in fish ponds) are not shared:

• because, in this case, any overfishing or even complete destruction of the fish in one country has no impact upon the availability of the resource in the other(s)

If a species occurs in two or more countries, that does not necessarily mean that the resource (species) is shared (just as countries may share the same species of trees, but they do not necessarily share the same forests).

Also, some species occur as a number of distinct populations which can be relatively separated from each other.

• for example, different populations of fish can migrate in different directions; one population migrates entirely within the borders of one country (= not transboundary), another migrates across borders between two or more countries (= a transboundary stock) (see Section 12).

These groups of fishes (or other animals) which are shared are called shared stocks (or transboundary stocks).

Technically, whether a stock is shared or not maybe defined by genetic criteria

• a stock which is shared between two or more countries is one in which the "gene pool" of the animals is shared, for example:

o fish which migrate from one country to another to spawn are a shared stock because the same individuals (or their offspring) occur in both countries (that is, the actual genes of the fish occur in both countries).

o fish in reservoirs in one country do not normally interbreed with fish in reservoirs in another – they have separate gene pools and are therefore separate stocks.

The extent of sharing of the gene pool varies between various species and stocks. There can be various levels (extents) of sharing of genes which will determine the extent of stock sharing and, therefore, help with setting priorities for stocks that need to be considered as transboundary.

However, it is not necessary to actually know about the various "gene pools" to determine whether stocks are transboundary or not, since this can usually be inferred from ecological criteria (e.g., if the populations are geographically separated by a waterfall, chances are that the stocks are distincts).

The opposite of a "shared" resource or stock is one which is a "national" (or "domestic") resource or stock.
The difference between transboundary and non-transboundary stocks/resources is important. The two require different management approaches:

• In particular, shared (transboundary) stocks require international co-operative management.

Countries can, and should, co-operate regarding management and development of all shared resources. But only with transboundary stocks is international co-operation actually required (because how the resource is managed by one country will affect the availability of that resource in another).

The existence of transboundary fishery resources is important in the context of the MRC because the 1995 Agreement focuses on joint management of shared resources within the Lower Mekong River Basin. Awareness of the relative transboundary nature of many Mekong fish stocks is therefore very important to implementation of the 1995 agreement.

transboundary water and fishery resources represent the key shared resource requiring joint-management. [Note: that the need to manage transboundary environmental impacts is an important but different subject which is covered further in Section 11 and below – here we are discussing transboundary resources].

What is important to understand for present purposes is that:

• only some fishery resources are shared (transboundary) resources;

• the reason why they are shared is because of ecological conditions in the river and ecological connectivity between countries:

o for example, ecological conditions necessitate individuals moving (migrating) from one area to another during the seasonal cycle. Where these areas occur in different countries the stocks are transboundary.

o river continuity, from upstream to downstream, (and vice versa), (see Section 3) enables this sharing of biological resources.

transboundary Impacts Caused by Activities in the Fisheries Sector--
For example, overfishing of a shared stock in one country will cause a decline of the availability of that stock in another country.

Another major area in which the activities undertaken within the fisheries sector cause transboundary impacts is through the introductions and transfer of living aquatic organisms from one water body to another.

[Note: technically a transfer is the release of an organism (animal or plant) within its natural range; an introduction is the release of an organism into an area beyond its natural range (i.e., into an area where it is an exotic or not-native). "Release" does not have to be deliberate; "escapes", from fish farms, are also classified as releases].

The release of living aquatic organisms into the wild can result in potential transboundary impacts:

• because the organisms released can move, via river connections, and across international borders

o fish and other organisms do not respect international borders – their distribution is determined by ecological factors, not political ones.

Note that the organisms being released may be either an exotic species (i.e., not native to the Mekong) or an exotic strain or variety of a native species (that is, the genetic characteristics of the animals may be different to those of animals of the same species in that area). This is important because the ecological complexity of the Mekong River system has resulted in much genetic diversity amongst the native aquatic animals (See section 12).

• once released animals enter their new environment, they can impact other organisms present in that environment:

o for example, competition for food, space, breeding sites etc.

o the nature of these impacts will depend upon the species (or variety) released, the nature of the receiving environment, and the species already present.

o these impacts are often negative in that native biodiversity in the receiving environment is often reduced.

The release of animals into the wild, therefore, needs to be managed effectively between countries to avoid transboundary impacts. The management of exotic aquatic species and genetic diversity of native species is a transboundary issue.

• Because of the high degree of natural genetic diversity in river basins (i.e., natural differences occur in the same species between different geographic areas within the basin – see Section 12) the inappropriate movement and release of native species (through aquaculture and/or stocking) is regarded as a major threat to biodiversity in the Mekong (and one of significant transboundary importance). In particular, hybridisation (that is, breeding one species or variety with another to mix their genes) is especially damaging to native biodiversity. [Note: this applies equally to fish and any other aquatic organisms including invertebrates and plants].

It is worth noting that the degree to which exotic species can establish in rivers such as the Mekong is influenced by the health of the river ecosystem.

• Under natural conditions, the great diversity of species present means that most (but not necessarily all) opportunities for exploitation of the ecosystem are fully occupied. Hence it is often difficult for alien (exotic) species to establish (= start breeding/sustained populations). But as ecological conditions deteriorate (due to the impacts of development), the native fauna may not be adapted to the new (degraded) conditions. This can provide ecological opportunities for the invasion of species better adapted to new local conditions.

o This is one reason why exotic species often do well in reservoirs and aquaculture ponds (etc.) because both kinds of environment (reservoirs and ponds) represent "degraded" environments (in as much as neither are natural).

o Therefore, the impacts of exotic (alien, invasive) species depend very much on river health.

[Note: this is not always the case. Exotic species can cause serious damage even in perfectly healthy natural environments].
River ecology therefore determines the likelihood of exotic species establishing, or having harmful effects; changes in river ecology (through human impacts) can also influence these considerations.

Introductions of exotic species or transfers of native species to or within the basin occur through two major kinds of activity:

(1) through aquaculture (fish farming) related activities

This is the most common source and is one of the best documented examples of transboundary impacts of fisheries activities. There are many species in the Mekong that have been introduced in one country, and have spread into another.

(2) inter and intra-drainage transfers of water

Where water resources are diverted between one catchment or sub-catchment and another, the organisms living in that water are also often transferred (and in some cases the organisms in the receiving catchment are provided with a route to invade the donor catchment). Animals and plants in the Mekong River basin are not only different to those in adjacent river basins, but different sub-catchments within the Mekong Basin can have significantly different animals and plants.

Therefore, connecting these faunas/floras together, via water diversions/transfers, can effectively result in introductions and transfers on a massive scale. Although obvious, this potential transboundary impact is very rarely considered in impact assessments of water diversion projects.

transboundary Environmental Effects on Fisheries--
Many activities in the Mekong River Basin can result in changes in river hydrology, form, function and ecology (Section 10). The aquatic animals and plants rely upon river hydrology, form, function and ecology for their existence. Both fisheries production and biodiversity in the fishery depend upon the aquatic animals and plants. Therefore, changes in river ecology (etc.) result in changes in the fishery.

transboundary environmental effects upon fisheries occur in two major ways:

• First, through activities in one country producing environmental impacts in another country, which directly affects the fishery (= transboundary environmental impacts).

o For example, water storage upstream affects flooding in a downstream country, which affects fish production.

o A transboundary environmental impact does not necessarily impact a transboundary resource. For example, fishery resources in the coastal region of the Mekong Delta are, in general, a national asset of Viet Nam alone (except for any internationally migrating species). But, the activities of upstream countries can have a significant impact upon that resource (see Section 10).

• Second, through local environmental impacts of activities in one country which have an impact upon a transboundary (shared) resource (fishery stock)

o for example, dredging river beds or altering river banks/vegetation. may not necessarily cause a direct environmental affect far downstream (e.g., on water quantity or quality) but if it affects the breeding ground (for example) of a migratory fish locally – the impacts may be felt in another country due to a reduction in the fish population.

The management of actual and potential transboundary environmental impacts is, of course, a core purpose of the MRC and the key one in relation to the WUP, BDP and Environment Programme. Because the fish and other aquatic animals depend so intimately upon the environment in which they live, transboundary environmental impacts can have very significant impacts upon fisheries in the Mekong River Basin. Such considerations are major links between the fisheries sector and the MRC's core programmes.

Fisheries examples illustrate that these relationships and linkages are complex. It can be difficult to decide when environmental issues are of local or transboundary relevance. The criterion (measure) is not just simply whether the environmental change in question is felt only locally. It also depends upon whether the environmental disturbance or change has an impact locally upon a shared resource (i.e., therefore the effect is felt through the shared resource, and outside the area of direct impact of the environmental disturbance).

Not all transboundary impacts are negative or cause damage. Because one country can have a negative impact upon resources in another, the opposite must also be true – that it can also undertake activities that benefit the other country(s). There are already some examples of this kind of regional co-operation and approach to resources management with fisheries in the Mekong:

• For example, the Mekong Giant Catfish is an endangered species in the Mekong. Fisheries authorities in Thailand have already started a stocking programme for this fish based on the release of artificially reared juveniles into the river. In an effort to reduce the impact of fishing upon the stock, fisheries authorities in Cambodia have eliminated certain fishing gears (at the cost of reduced revenues from the fishery) that are known to catch even the occasional adult catfish. In both cases, this has been done in the full knowledge that the activities in question will benefit not only themselves but also other countries – because the fish is a well known transboundary (shared) resource.

• Cambodia, Lao PDR, Thailand and Viet Nam are starting to co-operate on joint management programmes for other threatened fishes in the Mekong – particularly other "Giant" fishes (besides the Giant Catfish). This includes joint co-operation in artificial propagation and culture techniques and sharing information on wild stocks. Again, this is done not because of self-interest, but in the acknowledgement that these fish are not only important but are transboundary assets – and therefore require co-operative management.

• The MRC Fisheries Programme, through it fish migration studies, has also successfully established a regional network (i.e., in all four countries) of fishers to share information on transboundary, migratory fish stocks. It is not only governments and scientists that recognise the nature of these fisheries – the fact that the stocks are shared is well recognised by the fishers themselves (in fact it is they who provide this information in the first place). The next phase of this co-operation will hopefully be to begin actual co-operative management of these joint resources.

These examples are modest in their current extent and impact. But they signal both an awareness of the nature of shared resources and a willingness to promote better joint-management that bodes well for some of the tougher resource management issues that the MRC has to deal with over the coming years.

Summary--
transboundary issues and fisheries can be complex. Not all fishery resources are shared (transboundary). Those that are require joint management between the countries that share them. Development activities can cause changes in river ecology.

Fishery resources are dependent upon river ecology. Fisheries depend upon fishery resources. Therefore, any and all changes in river ecology can potentially affect fisheries. Where the effect is felt outside a country which caused it – this is regarded as a transboundary impact upon the fishery. Not all transboundary impacts are bad; countries can do things to benefit their neighbours too.

transboundary impacts can occur:

1. with direct impacts (e.g., fishing) on transboundary fishery resources (shared stocks);
2. through the movement and release of both exotic and native organisms;
3. through the impacts of transboundary changes in river ecology/environment on local fishery resources; and/or
4. through local environmental impacts upon a shared (transboundary) resource.

transboundary aspects of fisheries are important to the MRC, because they require international co-operative management to address them. It is therefore important to understand the transboundary nature of fisheries to understand the role of the MRC in the fisheries sector.

The transboundary nature of resources and the transboundary impacts of development are the result of river hydrology, form, function and ecology. Impacts can be caused between different countries only because their aquatic environments are inter-connected and inter-dependent. This is why transboundary fishery resources and transboundary impacts upon fishery resources need to be jointly managed by the four countries of the lower Mekong River Basin.