In the Caribbean region, fisheries have long been the mainstay of coastal communities, particularly in the island nations.

Overfishing

In the Caribbean region, fisheries have long been the mainstay of coastal communities, particularly in the island nations. Coral reef fisheries—predominantly artisanal, small-scale, subsistence fisheries—are an inexpensive source of protein and provide employment where few alternatives exist. In tourist areas, many fish are sold directly to local restaurants. For countries such as Belize and the Bahamas, the export market in snapper, grouper, and reef-associated lobster and conch generates millions of dollars for the national economy, supplying demand far away from these tropical sources. [41]

The open access of reef fisheries, typically with few regulations, makes reef fish particularly susceptible to overexploitation. Because most reefs are close inshore and geographically contained, fish distribution is highly predictable in space and time. [42] Portable fish traps, the most widely used fishing gear in the Caribbean, are cheap and effective. [43] Unfortunately, such traps can also be destructive and wasteful—destructive when fishers drop them directly onto the reef, breaking up the corals, and wasteful when they are lost underwater because the traps continue to catch fish for many months or years, a process known as ghost fishing. The life cycle of reef fish also makes them vulnerable to fishing pressure. Fishers selectively remove larger organisms because of their greater value, and one typical sign of overfishing is a decline in average size of target species. Because the largest individuals have the greatest reproductive output, removing them from the population reduces replenishment of the stock. [44]

Another particularly damaging form of overfishing in the Caribbean has been the targeting of spawning aggregations. Several of the larger grouper and snapper species, from areas spanning several hundred square kilometers, congregate at known localities once or twice a year to spawn in vast numbers. Where fishers know the location of such spawning aggregations, they can remove the entire population of a species over the course of just a few nights.

In heavily fished reef systems, the large, valuable fish—such as groupers and snappers—become so scarce that people fish for lower-valued species [45] (termed “fishing down the food web”). For example, in Bermuda herbivorous reef fish (e.g., parrotfish, surgeonfish, and triggerfish) increased from less than 1 percent of the catch in the 1960s to 31 percent in the 1990s. The shift led to a ban on fish traps in 1990 that is still enforced. [46]

Overfishing not only affects the size of harvestable stocks but can lead to major shifts, direct and indirect, in community structure, both of fish species and reef communities as a whole. [47] In the competition for space between corals and algae, herbivorous fish help to control algae, thus favoring the growth and recruitment of corals. [48] When the herbivores are removed, algae can flourish and coral cover is reduced. This effect is evident in the sequence of events that led to the dramatic decline of Jamaica’s reefs (see Box 2: Jamaica's Reefs: Back from the Brink). Overfishing can lead to short-term losses in biodiversity, the loss of species with critical roles in the ecosystem, and may also lower the resilience of the reef to other threats.

Modeling results. The Reefs at Risk indicator for the overfishing threat identified highly populated areas and areas where coastal shelves are narrow (such as in the Eastern Caribbean) as being under high threat, based on the large numbers of fishers and relatively small fishing area (see Map 6: Reefs Threatened by Overfishing). The analysis estimated that fishing pressure is lower in the Bahamas, where the human population is small. In the western Caribbean and Cuba, where many reefs are far from the mainland, the analysis also rated the threat as low.

It should be noted that this indicator does not capture fishing pressure from more remote locations or illegal fishing (see Chapter 2 - “Limitations of the Analysis” and Table 1: Reefs at Risk Analysis Method.) In the region as a whole, the study identified about 60 percent of reefs as threatened by overfishing (with about 30 percent each under medium and high threat). Destructive fishing practices (e.g., use of dynamite or cyanide) were not evaluated for the Caribbean, as they are rarely practiced in the region. The destructive impact of trap fishing and of lost fishing nets entangling reefs should be noted. To a broad approximation, these are likely to follow the patterns of fishing pressure as a whole.

Remedies. Effective management of coastal resources is crucial, especially along densely populated coastlines. Less intensive fishing will allow the fisheries resource to build up to the point where the harvest is balanced with the natural replenishment of the population. [49] Financial and other incentives can encourage sustainable fishing practices, while fines and penalties discourage illegal fishing and other breaches of sustainable practices. Licensing new fishers helps limit access to fisheries currently vulnerable to overfishing. Legal systems can also be put in place to restrict the catch of species subject to severe overfishing, such as the bans on all takings of selected conch species instituted in several Caribbean countries. Other controls limit the numbers caught, the size of individuals that may be taken (to ensure that individuals can reach breeding age), or the fishing gear used (for example, several countries now require the use of biodegradable panels in fish traps to avoid “ghost fishing” by lost traps). Seasonal restrictions can be used to protect species as they spawn. One of the most important tools, increasingly recognized and put into practice across the Caribbean, is the total closure of areas to fishing. Such “no-take zones” provide fish with a refuge, allowing spawning stocks to build up and adults to spill over into the surrounding waters. These zones have been shown to greatly increase overall catch levels from wider reef ecosystems. [50]

Notes

41 Hughes et al. (2003).

42 J.A. Bohnsack, "The Impacts of Fishing on Coral Reefs," in Proceedings of the Colloquium on Global Aspects of Coral Reefs: Health, Hazards and History. R. Ginsburg, ed. (Miami: Rosenstiel School of Marine and Atmospheric Sciences, University of Miami, 1993), pp. 196-200.

43 J.L. Munro, "Effects of Fishing on Coral Reef Ecosystems," in Proceedings of the Norway/UN Conference on the Ecosystem Approach to Sustainable Use of Biological Diversity. (Trondheim: Norwegian Directorate for Nature Management & Norwegian Institute Nature Research, 1999), p. 282.

44 Bohnsack (1993).

45 J.W. McManus et al. 2000. "Coral Reef Fishing and Coral-Algal Phase Shifts: Implications for Global Reef Status." ICES Journal of Marine Science 57:572-578.

46 J.N. Butler et al. 1993. "The Bermuda Fisheries: A Tradegy of the Commons Averted?" Environment 35 (1): 7-33.

47 C. Roberts. 1995. "Effect of Fishing on the Ecosystem Structure of Reefs." Conservation Biology 9(5): 988-995.

48 Bohnsack (1993).

49 B Chakalall, R. Mahon and P. McConvey, "Fisheries Governance in the Caribbean," in ACP-EU Fisheries Research Initiative Workshop: Proceedings of the Third Dialogue Meeting: Caribbean and Pacific and the European Union, Belize City, Belize, 5-10 December 1996 (Brussels: European Commission, 1997).

50 F.R. Gell and C.M. Roberts, The Fishery Effects of Marine Reserves and Fishery Closures (Washington DC: World Wildlife Fund, 2002).