title: Social networks and environmental outcomes.
abstract: Social networks can profoundly affect human behavior, which is the primary force driving environmental change. However, empirical evidence linking microlevel social interactions to large-scale environmental outcomes has remained scarce. Here, we leverage comprehensive data on information-sharing networks among large-scale commercial tuna fishers to examine how social networks relate to shark bycatch, a global environmental issue. We demonstrate that the tendency for fishers to primarily share information within their ethnic group creates segregated networks that are strongly correlated with shark bycatch. However, some fishers share information across ethnic lines, and examinations of their bycatch rates show that network contacts are more strongly related to fishing behaviors than ethnicity. Our findings indicate that social networks are tied to actions that can directly impact marine ecosystems, and that biases toward within-group ties may impede the diffusion of sustainable behaviors. Importantly, our analysis suggests that enhanced communication channels across segregated fisher groups could have prevented the incidental catch of over 46,000 sharks between 2008 and 2012 in a single commercial fishery.
authors.affiliation: Department of Natural Resources and Environmental Management, University of Hawaii at Manoa, Honolulu, HI 96822; Department of Botany, University of Hawaii at Manoa, Honolulu, HI 96822; Joint Institute for Marine and Atmospheric Research, University of Hawaii at Manoa, Honolulu, HI 96822; Australian Research Council Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, QLD 4811, Australia; michele.barnes@jcu.edu.au.
authors.forename: Michele L
authors.identifier: 0000-0002-1151-4037
authors.initials: ML
authors.lastname: Barnes
authors.affiliation: Department of Economics, University of Hawaii at Manoa, Honolulu, HI 96822; University of Hawaii Economic Research Organization, University of Hawaii at Manoa, Honolulu, HI 96822.
authors.forename: John
authors.identifier: 0000-0002-5816-9648
authors.initials: J
authors.lastname: Lynham
authors.affiliation: Joint Institute for Marine and Atmospheric Research, University of Hawaii at Manoa, Honolulu, HI 96822;
authors.forename: Kolter
authors.initials: K
authors.lastname: Kalberg
authors.affiliation: Department of Natural Resources and Environmental Management, University of Hawaii at Manoa, Honolulu, HI 96822;
authors.forename: PingSun
authors.initials: P
authors.lastname: Leung
mesh_terms: D000465:Algorithms; D000818:Animals; D003247:Conservation of Natural Resources / Q000706:statistics & numerical data; D017753:Ecosystem; D005398:Fisheries; D005399:Fishes; D006254:Hawaii; D006801:Humans; D012044:Regression Analysis; D012754:Sharks; D012944:Social Support
keywords: environmental outcomes; homophily; shark bycatch; social networks; sustainability