Fisheries and climate change

Rising ocean temperatures and ocean acidification are radically altering aquatic ecosystems. Climate change is modifying fish distribution and the productivity of marine and freshwater species. This has impacts on the sustainability of fisheries and aquaculture, on the livelihoods of the communities that depend on fisheries, and on the ability of the oceans to capture and store carbon (biological pump). The effect of sea level rise means that coastal fishing communities are in the front line of climate change, while changing rainfall patterns and water use impact on inland (freshwater) fisheries and aquaculture.

Generally, a fishery or fish cultivation is an entity engaged in raising or harvesting fish which is determined by some authority to be a fishery. According to the FAO, a fishery is typically defined in terms of the "people involved, species or type of fish, area of water or seabed, method of fishing, class of boats, purpose of the activities or a combination of the foregoing features". The definition often includes a combination of fish and fishers in a region, the latter fishing for similar species with similar gear types.

 

A fishery may involve the capture of wild fish or raising fish through fish farming or aquaculture. Directly or indirectly, the livelihood of over 500 million people in developing countries depends on fisheries and aquaculture. Overfishing, including the taking of fish beyond sustainable levels, is reducing fish stocks and employment in many world regions.

Aquaculture, also known as aquafarming, is the farming of aquatic organisms such as fish, crustaceans, molluscs and aquatic plants. water populations under controlled conditions, and can be contrasted with commercial fishing, which is the harvesting of wild fish. Broadly speaking, finfish and shellfish fisheries can be conceptualized as akin to hunting and gathering while aquaculture is akin to agriculture. Mariculture refers to aquaculture practiced in marine environments and in underwater habitats.

According to the FAO, aquaculture "is understood to mean the farming of aquatic organisms including fish, molluscs, crustaceans and aquatic plants. Farming implies some form of intervention in the rearing process to enhance production, such as regular stocking, feeding, protection from predators, etc. Farming also implies individual or corporate ownership of the stock being cultivated." The reported output from global aquaculture operations would supply one half of the fish and shellfish that is directly consumed by humans; however, there are issues about the reliability of the reported figures. Further, in current aquaculture practice, products from several pounds of wild fish are used to produce one pound of a piscivorous fish like salmon.

Particular kinds of aquaculture include fish farming, shrimp farming, oyster farming, algaculture (such as seaweed farming), and the cultivation of ornamental fish. Particular methods include aquaponics and Integrated multi-trophic aquaculture, both of which integrate fish farming and plant farming.

Silver Carp in Bangladesh

Fisheries policy in Bangladesh is still trying to get to grips with the major (universal) dilemmas of maximizing benefits from natural resources while, at the same time, ensuring an acceptable degree of equity in distribution of benefits and protecting the ecosystems that support the resources. During the twentieth century Bangladesh adopted one-sided production-oriented policies in the agricultural sector to feed the rapidly growing population. This strategy included increasing fish production, which was in decline mainly as a result of environmental degradation brought about by the expansion of agriculture. The solution was aquaculture development and later the promotion of culture-based fisheries and large scale stocking in the floodplains and beels (lakes) that previously sustained the capture fisheries. Although fish production per se in many cases may have increased as a result of this type of intervention, benefits are not socially and environmentally sustainable. 

 

Traditional leasing of water bodies is effective but not equitable because the powerful leaseholders control the access; and because the leasing arrangements are of short duration the leaseholders will try to maximize benefits, often at the expense of environment and biodiversity. These strategies have consequently caused serious negative environmental impacts and have further reinforced inequalities between local elites and poorer fishers. Although several attempts have been made to transfer fishing rights to poor fishers through community-based management arrangements,influential people tend to dominate these attempts when there are financial attractions such as subsidies for stocking and the opportunity for easily controlled profits. While stocking of fingerlings, gear bans and seasonal bans on all or some fishing gears were successful technically to conserve and enhance resources it led to exclusion and suffering of poor fishers. Culture-based fisheries have relatively high production, but need strictly enforced closed seasons to allow fish to grow, an activity which excludes poor subsistence fishers.

 

However, in some places people who participated with the expectations of considerable personal gains ceded when more resilient lower-cost practices such as sanctuaries were adopted. Local equity issues are partly mitigated when poor people are allowed to catch small (non-stocked species) for food. In the floodplains, public stocking has not been sustained as access to these larger open systems is very difficult to control and participants are unable to capture enough benefits or raise funds from the wider community, while landowners tend to take advantage of the situation and catch more of the stocked fish. In smaller, more closed waterbodies, groups of fishers are able to control access and can profit, but the risks and need for capital are high.

This is because commercial aquaculture has emphasized the production of more profitable large fish species such as silver carp but overlooked the nutritional contribution that small fish can make, says Dr. Shakuntala Haraksingh Thilsted, Senior Nutrition Adviser to CGIAR’s WorldFish Center. Dr. Thilsted, along with Dr. Patrick Dugan (Deputy Director General of WorldFish), came to IFAD headquarters in Rome on Friday, July 12^th to discuss the important role which small fish can and must play in aquaculture in the developing world. During their well-attended morning presentation, they also shared some of the latest findings and successes from a relevant IFAD-supported project in Bangladesh.