Qualitative network models in support of ecosystem approaches to bivalve aquaculture

Abstract

Predicting the effects of aquaculture development for coastal ecosystems remains challenging, particularly for data-limited systems, and tools that account for complex ecological interactions are needed to support ecosystem approaches to aquaculture. Here, we used qualitative network models (QNMs) to examine the potential community effects of increasing bivalve aquaculture in South Puget Sound, a large estuarine system in Washington, United States. QNMs are formalized conceptual models that require only a qualitative understanding of how variables composing a system interact (that is, the sign of interactions: +, –, and 0) and are therefore well-suited to data-limited systems. Specifically, we examined community-wide responses to scenarios in which bivalve cultivation effort increased for three different bivalve species (Manila clam Venerupis philippinarum, Pacific oyster Crassostrea gigas, and geoduck Panopea generosa). Further, we evaluated community-wide responses to the removal of benthic bivalve predators, a future increase in nutrient loadings, and combinations of these scenarios acting simultaneously. The scenarios enabled identification of potential trade-offs between increased aquaculture and shifts in the abundance of community members and assessment of the possible effects of different management actions. We also analysed the QNM to identify key interactions that influence the sign outcome of community responses to press perturbations, highlighting potential points for management intervention and linkages deserving of more focused quantitative study. QNMs are mathematically robust and highly flexible, but remain underutilized. We suggest that they may serve as valuable tools for supporting ecosystem approaches to aquaculture.

Attraction and repulsion of mobile wild organisms to finfish and shellfish aquaculture: a review

“…Recent advances have also directly incorporated attractive effects into foodweb models for bivalve aquaculture through the use of mediation functions (Ferriss et al 2016). Alternatively, qualitative network models have been developed to better understand trophic links and their impacts on ecosystem functioning using only qualitative data, which is useful in coastal systems as they are commonly data-limited (Reum et al 2015). Results from these types of studies may help identify priorities for additional empirical research on aquaculture-environment relations.…”

Development of social-ecological conceptual models as the basis for an integrated ecosystem assessment framework in Southeast Alaska

“…Appendix 1 contains the expanded version of the different species within each of these nodes. We maintained simplicity in these models by minimizing the number of variables in an effort to aid interpretation and reduce uncertainty (Reum et al 2015), but maintained sufficient realism to capture pivotal ecological dynamics.…”

Multi‐stakeholder perspectives on spatial planning processes for mariculture in the Mediterranean and Black Sea

“…The premise of the ecosystem approach (EA) stems from work undertaken throughout the 1990s, through the Convention on Biological Diversity (CBD) (UNCBD 1993;CBD Secretariat, 2000). The application of a broad-based EA is spreading as a policy-driven, science-based process for the management of all human activities, and in the marine environment the approach has as its goal the establishment of healthy and productive seas and oceans (Reum et al 2015;Gentry et al 2016;Oates & Dodds 2017). EA has progressively filtered through to fields including fisheries (Garcia et al 2003;Bianchi 2008) and marine spatial planning (Douvere 2008) and aquaculture (Soto et al 2008) under the EAA.…”

“…The application of a broad‐based EA is spreading as a policy‐driven, science‐based process for the management of all human activities, and in the marine environment the approach has as its goal the establishment of healthy and productive seas and oceans (Reum et al . ; Gentry et al . ; Oates & Dodds ).…”