The impact of fishing on a highly vulnerable ecosystem, the case of Juan Fernández Ridge ecosystem

Abstract

The Juan Fernández Ridge (JFRE) is a vulnerable marine ecosystem (VME) located off the coast of central Chile formed by the Juan Fernández Archipelago and a group of seamounts. This ecosystem has unique biological and oceanographic features, characterized by: small geographical units, high degree of endemism with a high degree of connectivity within the system. Two fleets have historically operated in this system: a long term coastal artisanal fishery associated with the Islands, focused mainly on lobster, and a mainland based industrial demersal finfish fishery operating on the seamounts which is currently considered overexploited. The management of these fisheries has been based on a classical single-species approach to determine output controls (industrial fleet) and a mixed management system with formal and informal components (artisanal fleet). There has been growing interest in increasing the exploitation of fisheries, and modernization of the fishing fleet already operating in the JFRE. Under this scenario of increased levels of fishing exploitation and the high level of interrelation of species it might be necessary to understand the impact of these fisheries from a holistic perspective based on a ecosystem-based modeling approach. To address these challenges we developed an Atlantis end-to-end model was configured for this ecosystem. The implemented model has a high degree of skill in representing the observed trends and fluctuations of the JFRE. The model shows that the industrial fishing has a localized impact and the artisanal fisheries have a relatively low impact on the ecosystem, mainly via the lobster fishery. The model indicates that the depletion of large sized lobster has leads to an increase in the population of sea urchins. Although this increase is not sufficient, as yet, to cause substantial flow-on effects to other groups, caution is advised in case extra pressure leads the ecosystem towards a regime shift.

Addressing initialisation uncertainty for end-to-end ecosystem models: application to the Chatham Rise Atlantis model

“…Atlantis models are end-to-end ecosystem models that can be used to model everything in an ecosystem from sunlight to market, including feed-back loops and flow-on effects (Audzijonyte et al, 2017a). There are many published Atlantis models (Link, Fulton & Gamble, 2010;Ainsworth et al, 2011;Ainsworth, Schirripa & Morzaria-Luna, 2015;Fulton et al, 2011;Weijerman et al, 2014;Sturludottir et al, 2018;Ortega-Cisneros, Cochrane & Fulton, 2017;Porobic et al, 2019;McGregor et al, 2019b), and sensitivities and uncertainties are beginning to feature in the more recently published work (Ortega-Cisneros, Cochrane & Fulton, 2017;Sturludottir et al, 2018, Ortega-Cisneros et al, 2018Hansen et al, 2019aHansen et al, , 2019bMcGregor et al, 2019b).…”

Local and remote physical processes driving variability of the planktonic system in the Juan Fernández Archipelago: A multidisciplinary framework providing conservation insights

“…The red colour represents an ascent (upwelling) of waters and the blue colour a subsidence of them indicator of phytoplankton photosynthetic activity, resulting altogether in a better inference about productivity. Despite the high value of in situ sampling and satellite imagery analysis for this work, the development of a high-resolution model for this area will significantly improve the understanding of physical processes in this system (Hormazábal et al, 2013;Medel et al, 2018;Morales et al, 2012;Porobic et al, 2019). Only then will it be possible to evaluate hypotheses to unravel the specific ecosystem mechanisms operating around RC and SC islands in the JFA.…”

“…The oceanographic features and high degree of marine endemism (Friedlander et al, 2016;Pequeño & Sáez, 2000;Rozbaczylo & Castilla, 1987) of the JFR determine significant ecosystem differences between the insular marine environment and the coastal upwelling zone of continental Chile. These observations and other relevant characteristics led to the classification of the JFR as a vulnerable marine ecosystem (Porobic et al, 2019) and motivated its declaration as a Marine Protected Area of Multiple Uses (MPA) by the Chilean government (Supreme decree no. 10 of 2018, Chile).…”

Exploring overlooked components of remote South‐east Pacific oceanic islands: Larval and macrobenthic assemblages in reef habitats with distinct underwater soundscapes

“…At RN, however, sea urchin noise was not recorded or was less evident. Sea-urchin barrens have been recently reported at RCI (see Porobic et al, 2019), raising concerns for the local community due to the evident loss of biodiversity generated by changes from algaedominated habitats to urchin barrens. These changes have been described elsewhere (e.g.…”