Abstract

Achieving sustainable use of kelps is key for small-scale fishers' livelihoods and biodiversity. During the last three decades, Chile has implemented different policy approaches to manage kelps. Unfortunately, assessments of the biological impacts of these management regimes have not received the attention they deserve. In this study, we explore biomass, density, size structure and holdfast diameter/stipe length relation of the kelp Lessonia spp., associated to a territorial user rights policy, which grant exclusive access to fishers, and a regional management plan policy which defines control rules in what were historically de facto open access areas. We compare these with marine protected areas where harvesting is banned, thus serving as a benchmark. The study was performed along the coast of two of the main kelp harvesting regions of Chile. The analyses, performed in two time periods, shows that biomass is greater inside areas managed through territorial user rights and in marine protected areas compared to areas where regional management plans have been implemented, which perform in a similar way to open access sites. Enforcement is a key driver of kelp response. Densities of recruits and juveniles are higher in areas where harvesting and gathering are allowed, whilst adult plants have higher density in marine protected areas. In all cases, kelps have become denser after eleven years. The holdfast diameter/stipe length relation provides an indicator of protection efficiency: stricter regulatory measures are related to larger holdfast diameters and shorter stipes. We conclude that, in general, territorial user rights policies and marine protected areas have contributed to the conservation of wild intertidal Lessonia populations. Results highlight the potential of the regional management plans policy to improve kelp management, but it will probably need important adjustments to enhance enforcement and compliance. In addition management innovations such as rotational harvest strategies could provide an important complement which should be further assessed.