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Thematic : Fisheries
Language : English
Note
This paper presents the case for adopting ecosystem rebuilding as the goal
of fisheries management. Movement toward this goal may represent the only hope for
fisheries, as we know them, to exist 50 years in the future alongside essential services
provided by marine ecosystems. First, I review archaeological, historical, and recent evidence
that bears witness to a long, dismal record of overexploitation. Second, I examine
the ecological effects of overfishing on aquatic ecosystems. Fish with life histories and
spatial behavior inimical to harvesting are selectively removed, both within and among
species. The loss of keystone species and the replacement of high-value, demersal resources
with pelagic, rapid-turnover, low-value species shifts the nature of ecosystems, evidenced
by accelerating local extinctions and a worldwide decline in trophic level. Disconcertingly,
harvest limits that appear safe by single species evaluation can engender ecosystem changes
that are hard to reverse. Driven by a progression of clever human harvest technologies,
three ratchet-like processes have brought about episodes of depletion. ‘‘Odum’s ratchet’’
is ecological in nature, comprising depletion and local extinction. ‘‘Ludwig’s ratchet,’’
economic in nature, is a positive feedback loop between increased catching power and
serial depletion, driven by the need to repay borrowed money. ‘‘Pauly’s ratchet’’ is cognitive,
shifting the baseline of what each generation regards as primal abundance and diversity.
Third, a rebuilding policy goal is distinguished from that of sustaining current catches and
biomass, since the baseline can refer to present misery. In this sense, present policies can
inadvertently foreclose future options for the generation of food, wealth, and services from
ocean resources. A policy to rebuild ecosystems can reverse this trend and maximize
economic value in tomorrow’s markets, where supply will vastly outstrip demand for highquality
fish products. Fourth, I outline a novel methodology, termed ‘‘Back to the Future,’’
that can implement a goal of ecosystem rebuilding. Models of past ecosystems are reconstructed
using information about the presence and abundance of species from historical
documents, archaeology, and local and traditional environmental knowledge (LEK and
TEK). Economic evaluation compares past with present and alternative ecosystems. ‘‘Back
to the Future’’ gives the TEK of aboriginal and indigenous peoples a valuable, direct
function in resource management. Finally, I discuss two practical management measures,
paralleling recent developments in terrestrial reconstruction ecology, the implementation
of large no-take marine reserves, and the reintroduction of high-value species that were
formerly endemic.
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Keywords : Rhinolophus macrotis
Encoded by : Pauline Carmel Joy Eje
