|| View Thread | Return to Index | Read Prev Msg | Read Next Msg ||
Wise Coastal Practices for Sustainable Human Development Forum
Posted By: Omar Defeo and Juan Carlos Castilla
Date: Tuesday, 8 June 1999, at 6:52 p.m.
Key words: marine exploitation areas, property rights.
BACKGROUND: Coastal systems in Latin America are affected by increasing land- and ocean-based activities: tourism, recreation, fishing, mariculture, domestic and industrial waste disposal, military activities, transportation, mining and energy industries. When unplanned, these activities impact on and threaten biodiversity, including important species from an economic point of view. Small- scale, artisanal fisheries constitute an important socioeconomic component of the Latin American and Caribbean fisheries. These fisheries provide an important source of employment and represent a key source of high quality food, generating important direct incomes to artisanal communities and elevated export revenues to the countries of Latin America. These fisheries could be characterized by 6 contrasting phases to describe the long-term landing and export value patterns: development, expansion, overexploitation, closures, stabilization and institutionalisation /consolidation. In the majority of the cases, only the former three phases occurred and several coastal fisheries are, at present, dramatically over-exploited and have collapsed. One of the main causes for these collapses is that fishers have not been included in the discussions about management. Here we present two cases in which the experimental and co- management practices were set as useful approaches to manage these fisheries.
1. THE YELLOW CLAM (Mesodesma mactroides) FISHERY IN URUGUAY
The yellow clam Mesodesma mactroides is a sedentary bivalve distributed along the warm temperate intertidal of the Atlantic coast of South America. This species is artisanally harvested (shovels and hand-picking) in sandy beaches of Brazil, Argentina and Uruguay. In Uruguay, the historical phases of the yellow clam fishery closely resemble those described earlier. Landings of yellow clam catches presented low levels before the decade of the 80's, when statistical coverage of the activity did not exist. The expansion phase began in the 80's, in which landings increased up to 3.5 times in five years (from 62 t in 1981 to 219 t in 1985). Catches decreased more than 100% from 1985 to 1986, and in the first quarter of 1987 only 11 t were caught (overexploitation phase). Then the fishery was closed for 32 consecutive months, from April 1987 to November 1989. The main idea underlying the closure of the fishery, promoted by resource biologists, was to consider this closure as a management experiment (a stepwise process of learning by doing) to investigate the effects of fishing activities on the demography of the yellow clam. During the closure of the fishery, the interaction between resource users, coastal marine authorities, and fishery biologists during the experimental process was identified as a wise practice. The small and well-defined group of local fishers was specially involved in enforcing regulations in order to set up an accurate control of the experiment. The National Institute of Fisheries approved and encouraged the scientific initiative (i.e. a good political climate was in place).
The experiment provided significant information from an ecological point of view. The long-term study has shown that fishing can influence the demography and abundance of shellfishes, beyond the effects of exploitation, thus highlighting the ecological implications of humans as top predators in the system, and also as a source of physical disturbance associated with harvesting. Experimental manipulation of the fishery allowed identifying positive and negative effects of fishing, with meaningful management implications. The fishery was reopened from December 1989 onwards, in which two additional operational management strategies were implemented: (a) A minimum catch volume per fisher. Priority was given to those fishers with longer activity in the fishery. (b) A spatial management scheme, considering habitat heterogeneity, which accounts for spatial and temporal variations in resource abundance and in the fishing effort exerted. The strong and rapid resource recovery was reflected in the high catch per unit effort achieved by the fishers when the fishery was reopened during the summer of 1990. Allocation of property rights to each fisherman resulted in a useful mechanism to avoid "the tragedy of the commons", and to maintain the stock at desirable levels and to improve the quality of life of fishers (these last two elements are two quantitative indicators). Thus, the stabilization phase occurred after the closed season. In this period, the catch per unit of effort was two times higher than in pre-closure years. Due to a decision of the management body, the fishery was left as an open access system since 1992, which determined another collapse a year after. Thus, the 6th fishery phase, the "consolidation" period, was not fulfilled because of an unwise decision by the government authority.
2. COASTAL ARTISANAL SHELL FISHERIES IN CHILE
The Chilean benthic fauna is diverse. Over sixty species of invertebrates generate annual landings of about 150,000 tons, with an export value exceeding 100 million dollars. Harvesting is restricted to artisanal divers and coastal subsistence food gatherers. In the past 15 years, a number of shellfishes were over-exploited and in some cases, the fishery collapsed. Fishery closures were unsuccessful, and thus extensive illegal activities occurred along the country. In 1991, the Chilean Fishing and Aquaculture Law was approved. It incorporates main fishery and ecological knowledge developed by local scientists, such as the implementation of marine reserves and "Marine and Exploitation Areas" (MEA's). These MEA's, defined over reduced extensions of coastal segments (i.e., <100 ha of sea bottom), were accessed only by organised artisanal communities, and were granted for two years on the basis of previously agreed management and exploitation plans between the fishers, the maritime authorities and the scientists.
Community involvement improved the effectiveness of shellfish management programs and constitutes an effective tool by which fishers, scientists and managers could interact to improve the quality of the regulatory process. Co-management of small coastal MEA's resulted in larger catches, catch per unit of effort and net economic revenues perceived by the fishers as a result of higher quality of the product (individual sizes) when compared with open access fishing grounds. Promising results on natural re-stocking of shellfishes in coves or "Caletas" with organized fisher communities offer hopes for the future sustainable use of benthic resources. Co-management provides fishers the possibility to share decision-making authority. Indeed, the perception of ownership by the fishers is one of the most important focal points that determined the success of this Wise Management Practice developed in Chile.
DISCUSSION: These examples represent successful co- management pilot experiments. But there is a problem of scale that precludes the extent of generalization to other cultures and regions. Each region has its own way of achieving their respective co-management wise objective.
This manuscript is based on the following papers:
Castilla, J.C. (1994) The Chilean small-scale benthic shellfisheries and the institutionalization of new management practices. Ecological International Bulletin 21: 47-63.
Castilla, J.C. (1997) Chilean resources of benthic invertebrates: fishery, collapses, stock rebuilding and the role of coastal management areas and National Parks. In Hancock, D.A., Smith, D.C., Grant, A. and Beumer, J.P., eds. Developing and Sustaining World Fisheries Resources: The State of Science and Management. Second World Fisheries Congress proceedings. CSIRO, Collingwood, Australia: 130-135.
Castilla, J.C. and Fernández, M. (1998) Small-scale benthic fisheries in Chile: on co-management and sustainable use of benthic invertebrates. Ecological Applications 8:S124-S132.
Castilla, J.C., Manríquez, P., Alvarado, J., Rosson, A., Pino, C., Espoz, C., Soto, R., Oliva, D. and Defeo, O. (1998) The artisanal caletas as unit of production and basis for community-based management of benthic invertebrates in Chile. Canadian Special Publication of Fisheries and Aquatic Sciences 125: 407-413.
Defeo, O. (1989) Development and management of artisanal Uruguayan exposed sandy beach. PhD Dissertation, CINVESTAV-IPN, Merida,Mexico.
Defeo, O. (1996) Experimental management of an exploited sandy beach bivalve population. Revista Chilena de Historia Natural 69: 605-614.
Defeo, O. (1998) Testing hypotheses on recruitment, growth and mortality in exploited bivalves: an experimental perspective. Canadian Special Publication of Fisheries and Aquatic Sciences 125: 257-264.
Defeo, O. and de Alava, A. (1995) Effects of human activities on long-term trends in sandy beach populations: the wedge clam Donax hanleyanus in Uruguay. Marine Ecology Progress Series 123: 73-82.
Defeo, O., de Alava, A., Valdivieso, V. and Castilla, J.C. (1993) Historical landings and management options for the genus Mesodesma in coasts of South America. Biología Pesquera (Chile) 22: 41-54.
Lubchenco, J., Allison, G.W., Navarrete, S.A., Menge, B.A., Castilla, J.C., Defeo, O., Folke, C., Kussakin, O., Norton, T. and Wood, A.M. (1995) 6.1.9. Coastal systems. In: United Nations Environment Programme. Global Biodiversity Assessment. Section 6: Biodiversity and ecosystem functioning: ecosystem analyses. Cambridge University Press, Cambridge, U.K.: 370-381.
SEND YOUR REACTION/RESPONSES TO THE .
|| View Thread | Return to Index | Read Prev Msg | Read Next Msg ||