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

Several administrative polices have been implemented in order to reduce the negative impacts of fishing on natural ecosystems. Four eco-social models with different levels of complexity were constructed, which represent the seaweed harvest in central-northern Chile under two different regimes, Management and Exploitation Areas for Benthic Resources (MAEBRs) and Open Access Areas (OAAs). The dynamics of both regimes were analyzed using the following theoretical frameworks: (1) Loop Analysis, which allows the local stability or sustainability of the models and scenarios to be assessed; and (2) Hessian´s optimization procedure of a global fishery function (GFF) that represents each dynamics of each harvest. The results suggest that the current fishing dynamics in MAEBRs are not sustainable unless the market demand presents some type of control (i.e. taxes). Further, the results indicated that if the demand changes to a self-negative feedback (self-control) in MAEBRs, the stability is increased and, simultaneously, a relative maximum for the GFF is reached. Contrarily, the sustainability of the model/system representing the harvest (principally by cutting plants) in OAAs is not reached. The implementation of an “ecological” tax for intensive artisanal fisheries with low operational cost is proposed. The network analysis developed here is proposed as a general strategy for studying the effects of human interventions in marine coastal ecosystems under transient (short-term) dynamics.

[1]  Barbara A. Knuth,et al.  Participation Rhetoric or Community-Based Management Reality? Influences on Willingness to Participate in a Venezuelan Freshwater Fishery , 2004 .

[2]  Stephen R. Carpenter,et al.  Cascading Trophic Interactions and Lake Productivity , 1985 .

[3]  John E. Parks,et al.  Dangerous targets? Unresolved issues and ideological clashes around marine protected areas , 2003 .

[4]  Richard Levins,et al.  A Response to Orzack and Sober: Formal Analysis and the Fluidity of Science , 1993, The Quarterly Review of Biology.

[5]  R. Lewontin,et al.  Biology Under the Influence: Dialectical Essays on Ecology, Agriculture, and Health , 2007 .

[6]  J. Vásquez,et al.  Production, use and fate of Chilean brown seaweeds: re-sources for a sustainable fishery , 2008, Journal of Applied Phycology.

[7]  M. Ortiz.  Qualitative modelling of the kelp forest of Lessonia nigrescens Bory (Laminariales: Phaeophyta) in eulittoral marine ecosystems of the south–east Pacific: an approach to management plan assessment , 2003 .

[8]  A. Bodini,et al.  A Multimethodological Approach for the Sustainable Management of Perifluvial Wetlands of the Po River (Italy) , 2000, Environmental management.

[9]  R. Levins.  The internal and external in explanatory theories , 1998 .

[10]  S. Jentoft,et al.  From the bottom up: Participatory issues in fisheries management , 1996 .

[11]  S. Thrush,et al.  Disturbance to Marine Benthic Habitats by Trawling and Dredging: Implications for Marine Biodiversity , 2002 .

[12]  Jun'ichi Kotoku,et al.  An Introduction to Optimization Theory. , 2016, Igaku butsuri : Nihon Igaku Butsuri Gakkai kikanshi = Japanese journal of medical physics : an official journal of Japan Society of Medical Physics.

[13]  R. Lewontin,et al.  How different are natural and social science , 1998 .

[14]  B. Broitman,et al.  Monitoring the sustainability of Lessonia nigrescens (Laminariales, Phaeophyceae) in northern Chile under strong harvest pressure , 2014, Journal of Applied Phycology.

[15]  T. Kompas.  Fisheries Management: Economic Efficiency and the Concept of 'Maximum Economic Yield' , 2005 .

[16]  R. Levins.  The strategy of model building in population biology , 1966 .

[17]  Ferenc Jordán,et al.  Weighting, scale dependence and indirect effects in ecological networks: A comparative study , 2007 .

[18]  T. Agardy,et al.  Global marine conservation policy versus site-level implementation: the mismatch of scale and its implications , 2005 .

[19]  J. Vásquez.  Lessonia trabeculata, a Subtidal Bottom Kelp in Northern Chile: A Case Study for a Structural and Geographical Comparison , 1992 .

[20]  Robert E. Ulanowicz,et al.  Assessment of long-term changes of ecosystem indexes in Tongoy Bay (SE Pacific coast): Based on trophic network analysis , 2016 .

[21]  D. Wilson,et al.  Social theory and fisheries co-management , 1998 .

[22]  R. Levins,et al.  Re-stocking practices and illegal fishing in northern Chile (SE Pacific coast): a study case , 2011 .

[23]  J. Vásquez,et al.  Limiting factors in optimizing seaweed yield in Chile , 1993, Hydrobiologia.

[24]  R Levins,et al.  DISCUSSION PAPER: THE QUALITATIVE ANALYSIS OF PARTIALLY SPECIFIED SYSTEMS , 1974, Annals of the New York Academy of Sciences.

[25]  Steven A. Murawski,et al.  Ten Commandments for Ecosystem-Based Fisheries Scientists , 2007 .

[26]  J. Vásquez,et al.  The Lessonia nigrescens fishery in northern Chile: “how you harvest is more important than how much you harvest” , 2012, Journal of Applied Phycology.

[27]  W. Arthur.  Positive feedbacks in the economy , 1990 .

[28]  C. Roberts,et al.  Benefits beyond boundaries: the fishery effects of marine reserves , 2003 .

[29]  Michel J. Kaiser,et al.  Importance of Attitudinal Differences among Artisanal Fishers toward Co‐Management and Conservation of Marine Resources , 2005 .

[30]  Olivier Guyader,et al.  Estimating MSY and MEY in multi-species and multi-fleet fisheries, consequences and limits: an application to the Bay of Biscay mixed fishery , 2013 .