Explore the network
Every dot is an actor; every line is a documented relationship. Drag nodes, scroll to zoom, and hover for details on any actor or tie. Thicker lines indicate more frequent mandated interaction.
Best on a larger screen. If the map is cramped, open it full-screen below.
What the network shows
SCDNR controls entry to the industry
SCDNR Shellfish Management holds more direct ties to individual growers than any other actor in the network — 31 direct permitting relationships, the highest out-degree of any node. That is the plain fact of who decides who gets to operate. Its formal brokerage profile adds a second, less visible layer: it is also the network's leading Representative, the actor most likely to carry regulatory authority outward to other sectors, and its leading Liaison, bridging sectors — industry, science, advocacy — that would otherwise have no connection to each other. Capacity lost at this one office would both slow permitting directly and disconnect parts of the network that depend on it as their only link.Sea Grant is the front door to the science
The S.C. Sea Grant Consortium has the highest overall betweenness centrality in the network — the most boundary-spanning actor by that general measure — and is its leading Gatekeeper: outside actors reach the science and extension sector overwhelmingly through it. It scores highest of any actor across four of the five formal brokerage roles.The growers' association plays both positions
SCSGA is nearly tied as the top gatekeeper and the second liaison — it both organizes its own sector and bridges disconnected ones. For a volunteer-run trade association, that is an unusually heavy structural load.Burden concentrates on growers
117 of 275 relationships impose administrative burden — permits, reporting, inspections, compliance. Coding burden tie-by-tie, rather than actor-by-actor, shows exactly which relationships in the permitting system produce friction, and where added capacity or coordination would relieve it.How it was built
Relationships were coded from statutes and regulations, public records, organizational documents, and a 2024 working group survey; every tie carries an evidence tier and a source note. Actors are classified by sector and, following the Advocacy Coalition Framework, by policy coalition. Administrative burden is coded at the level of the individual relationship using Herd and Moynihan's typology. Centrality and brokerage statistics (Gould & Fernandez, 1989) were computed in R with igraph and the sna package; results were independently verified in Python. The interactive maps are built with visNetwork.
A note on terminology. Gould and Fernandez's five brokerage roles describe only indirect paths — cases where one actor reaches another through a broker. Direct authority, such as SCDNR issuing a permit straight to a grower, is a one-step tie and is captured instead by degree centrality, not by the brokerage roles. "Gatekeeper" and "Liaison" in this typology are specific, technical categories and do not map one-to-one onto everyday usage of those words.
Data & full results
- Full results tables — betweenness centrality and all brokerage roles, top ten actors each
- centrality_results_v2.csv — degree and betweenness for all 104 actors
- brokerage_results_v2.csv — five Gould-Fernandez brokerage counts for all 104 actors
- GitHub repository — code and version history
About the researcher
Kate Chatman is an MPA/EVSS dual-degree candidate at the College of Charleston, working with the S.C. Sea Grant Consortium. This network analysis is one component of her thesis, Closing the Governance Gap: Shellfish Mariculture in South Carolina, which examines why permitted production lags what the coastline can support — and where targeted investment and coordination could close the gap.
Contact: chatmankate@gmail.com