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Introduction | Identification | Impacts | Causes | Actions | More Info
Impacts
What are some of the biological and physical impacts to coral reefs?
Using a squirt bottle, a fisher sprays a cloud of cyanide to stun targeted fish. Unfortunately, corals, other invertebrates, and smaller, non-target fish that find themselves in the cyanide cloud are also stunned and often killed. This leads to the unintended deaths of these non-target organisms also known as bycatch. In addition, the live reef food fish trade concentrates primarily on catching species of grouper (especially Cromileptes spp., Plectropomus spp. And Epinephelus spp.), and Napoleon wrasse (Cheilinus undulatus). In some areas, these species have become locally extinct. The widespread removal of these larger, predatory reef fish disturbs the ecological balance of the reef. As these reef fish become more difficult to find, wild juveniles (fry and fingerlings) are increasingly being targeted. These juveniles are kept in concrete ponds and floating net cages and grown-out to a marketable size (Sadovy and Pet 1998). This practice is becoming more common in Southeast Asia for the grouper mariculture industry primarily in Taiwan and Thailand (see ACIAR’s Grouper Project at: http://www.enaca.org/ACIAR/) and its effects on reef fish populations is relatively unknown (Sadovy 2000; Sadovy and Lau 2002; Sadovy and Vincent 2002).
In addition to cyanide use, targeting groups of reef fish during spawning is a concern. Reef fish generally form large aggregations during their reproductive season and fishers are often aware of these spawning sites, times, and seasons. By fishing these large groups, entire breeding populations can be eliminated (USCRTF 2000). Thus the general problem of overfishing is a major concern in the live reef food fish trade, possibly a larger problem than the use of cyanide.
Can coral reef damage also impact local communities and economies?
Overfishing of local reefs leads to very low levels of fish stocks and other reef organisms that can be harvested by local communities. Therefore the live food fish trade can have devastating impacts on communities that are dependent on local reefs for food and income. In addition, as reef fish become more difficult to find, local fishers are forced to dive deeper and for longer periods of time. An increase in diving-related injuries has resulted including paralysis and in some cases, death. Lastly, unhealthy reefs are less attractive to tourists who are looking to dive and snorkel on biologically diverse and colorful coral landscapes. Local businesses dependent on tourism will therefore be affected by degraded reef ecosystems.
While selling live fish for the live reef food fish trade offers positive economic benefits to fishers, a range of longer-term negative impacts can undermine these benefits. Most notable is the overexploitation of reef fish stocks. In most countries engaged in the LRFFT, there are few restrictions on catch or fishing effort and there is a lack of effective regulations and enforcement to prevent this over-harvesting. In developing countries, poor fishers with few alternative employment options exacerbate the ‘common property’ nature of LRFFT fisheries by remaining in an overexploited fishery despite dwindling returns (Pauly et al. 1989; McManus 1996).
The potential for earning more money from the LRFFT is not always realized. In the Solomon Islands, fishers receive only 25% more for LRFFT species than when they supply the same species to fresh fish markets in Honiara (Donnelly et al. 2000) despite the extra costs of keeping the fish alive for export. Even in Australia, frozen prices for Napoleon wrasse and flowery cod are only 50% and 25% lower, respectively, than the prices obtained for selling these fish alive. Therefore, high prices paid by consumers for certain LRFFT do no necessarily translate to high prices received by fishers at the supply end of the market chain. The extra costs associated with keeping fish alive also need to be considered for the LRFFT. |  | | Customers selecting fish from floating pens for consumption at a nearby restaurant.
Location: Near Nha Trang, Vietnam
Photo by: J. Oliver
(from ReefBase: http://www.reefbase.org |
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