The Lessonia nigrescens fishery in northern Chile: “how you harvest is more important than how much you harvest”

Abstract

In Chile, management of natural resources usually starts right before its imminent collapse or after evident declination. In the northern area of the country, the fishery of brown seaweeds has an enormous social, ecological, and economical importance. More than 11,000 people depend directly or indirectly on the collection and harvesting of this resource. Ecologically, kelps constitute areas for food, reproduction, and refuge for hundreds of invertebrates and fish species. Economically, landings up to 300,000 dry tons per year represent close to US $60 million for the industry. Until 2002, the Chilean brown seaweed fishery was mainly sustained by natural mortality, where plants cast ashore were collected by artisanal fishermen. Since then, three brown seaweed species of economic importance (Lessonia nigrescens, Lessonia trabeculata, and Macrocystis pyrifera) have been intensively harvested in coastal areas between 18°and 32°S. To manage kelp populations along the northern Chilean coast, regulations have been based on the principle "how you harvest is more important than how much you harvest". This exploitation strategy has been adopted in consensus between fishermen, industries, governmental entities, and scientists. Since L. nigrescens represents more than 70% of total brown seaweed landings, this study tests the effects of L. nigrescens harvesting on the following population variables: (1) abundance, (2) distribution, (3) juvenile recruitment, (4) plant morphology, (5) frequency of reproductive plants, and (6) biodiversity of the macroinvertebrate community associated to kelp holdfasts. Our results show that, despite the enormous harvesting pressure on Lessonia density and biomass, the associated macroinvertebrate richness has been maintained, due to normal plant growth and high recruitment all year round.

Early succession of micro‐periphyton communities in kelp bed and barren ground ecological systems

“…fishermen remove the algae from rocks using metal bars; Vásquez et al . ; authors' personal observations).…”

Holdfast fragmentation of Macrocystis pyrifera (integrifolia morph) and Lessonia berteroana in Atacama (Chile): a novel approach for kelp bed restoration

“…Various studies not only evaluated the effects of harvesting techniques, including their immediate impact, but also tried to forecast long-time consequences. In addition, they expressed concern about high extraction levels, harvesting procedures, and unprofessional management techniques practiced by local fishermen (Santelices & Ojeda 1984b;Vasquez et al 2012;Westermeier et al 2013a).…”

Self-feedbacks determine the sustainability of human interventions in eco-social complex systems: Impacts on biodiversity and ecosystem health

“…Therefore, the drastic increase of landings experienced in the last years is likely a consequence of illegal extractive harvest by cutting plants in intertidal and subtidal environments [19, Ortiz personal observation ]. This agrees with our models, which show that, independent of the complexity level, the harvest dynamics of seaweeds observed the last 13 years, principally in OAAs along the Chilean coast, would cause an unstable or unsustainable relative minimum for this fishery.…”