Port development and expansion of the scale presented in recent proposals for Quonset and Providence can be expected to increase foreign vessel traffic in Narragansett Bay by at least 350%. Increase in ship traffic will mean larger volumes, and greater frequencies of ballast water discharges into the Bay. Since ship ballast is the largest known vector for transferring marine organisms between coastal regions, Rhode Island's risk of bioinvasions will become higher with the increase in vessel traffic. This study presents information on known introductions of marine organisms to Narragansett Bay, and summarizes some of the major social, economic and environmental costs that could result if an invasion occurs in the Bay. Based on the finding that Rhode Island will face a significantly greater risk of introductions, I address the question: Does the state of Rhode Island have a role in preventing future ballast-mediated marine bioinvasions in Narragansett Bay?

The question of whether Rhode Island has jurisdiction to address the problem of exotic introductions through regulating the ballast water of commercial shipping is complicated by the fact that some federal, as well as international ballast controls already exist. However, national and international legislation addressing the problem of marine bioinvasions is currently insufficient to ensure the optimal available protection to Rhode Island waters. Constitutional, statutory, and case law analysis, indicates that the state does have, within certain limits, concurrent jurisdiction to regulate the ballast of commercial shipping to prevent introduction of invasive marine species.

The study reviews several policy alternatives potentially applicable in state ballast control and bioinvasions prevention. Options considered include risk-communication, direct regulation, ballast tax, and a liability system. A combination of mandatory ballast exchange regulations and a strict, collective liability system supported by assurance bonding has great potential to increase bioinvasions prevention and relieve state monitoring efforts. However, a liability requirement will present significant new costs to shipping, and if applied on the state, as opposed to national level, it will likely discourage vessels from calling on state ports. Therefore, after evaluating market and non-market strategies, I conclude that, from the several policies that show potential for state-level ballast management, a direct ban on the discharge of untreated ballast into state waters is the only currently available option that both ensures adequate prevention, and falls within the limits of state jurisdiction over ballast.

The most effective ballast treatment method currently practicable for ships in international trade is ballast exchange, i.e. the exchange of coastal ballast with open ocean water, generally recommended to take place outside the 200 mile exclusive economic zone and in water deeper than 2000 meters. To achieve needed improvements in protection against ballast-mediated species introductions, Rhode Island should, through a legislatively appointed lead agency on ballast (RIDEM or CRMC), enact mandatory ballast exchange regulations for transoceanic vessels calling on state ports, prohibiting the discharge of untreated ballast into state waters.