EPA's Vessel General Permit and Small Vessel General

To remove biofouling organisms, and to reduce or slow the attachment of new organisms,
vessels perform underwater ship husbandry or hull husbandry, i.e., the maintenance of the
underwater portions of a vessel. Hull husbandry includes the application of antifouling coatings
(AFCs) and removal of biofouling organisms during dry dock periods, as well in-water hull
cleaning. The shipping industry performs hull husbandry primarily for economic reasons.
Biofouling on a ship’s hull increases the hydrodynamic drag of the vessel and leads to increased
fuel consumption (Chambers et al. 2006). It has been estimated that fouling increases the annual
fuel consumption of the world’s commercial shipping fleet by 40 percent, or 120 million tons of
fuel at a cost of about $ 7.5 billion per year, in year 2000 dollars (GISP 2008).
Underwater hull cleaning can be quite effective at removing marine fouling; however, the
effluent stream from cleaning is difficult to control. The potential for ANS release resulting
from the uncontained discharge of underwater cleaning effluent is widely recognized. For
example, underwater hull cleaning has been banned by the ANZECC Code of Practice
(ANZECC 1997). Underwater hull cleaning is also prohibited in California, Maine, and
Massachusetts (EPA 2011).
As described in the BE, underwater hull husbandry has the potential to spread ANS by releasing
them into the environment. To examine the ANS risks posed by various hull cleaning
operations, researchers from the New Zealand National Institute of Water and Atmospheric
Research (NIWA) visited hull cleaning facilities in four New Zealand ports where vessels were
removed from the water for cleaning (drydock and haul-out facilities) or where fouling
organisms were removed underwater by divers (Floerl et al. 2005). For the operations examined,
physical removal of fouling assemblages from vessel hulls did not result in mortality of all
organisms. Most fouling organisms (72%) survived and remained viable after removal using
underwater hull cleaning methods, which did not involve exposure to air or high-pressure water
blasting. The overall viability of organisms removed from hulls was lowest in haul-out facilities
(16 %) and drydock facilities (43 %), where fouling organisms were often exposed to air, highpressure
freshwater blasting, and trampling.
Vessel hull fouling and underwater husbandry thus provide two pathways for ANS invasions.
To address these concerns, EPA included the following requirements in the VGP (suggested
measures are not included here or in the Description of the Action section; for example, the VGP
does not require AFCs, but if owners/operators use AFCs, they are required to “give
consideration” to selecting products that maximize efficacy but minimize adverse environmental
effects):
� Minimize the transport of attached living organisms when traveling into U.S. waters from
outside the U.S. economic zone or between Captain of the Port zones.
� For underwater hull cleaning, vessel owners/operators must, when feasible, use a vacuum
or other control technologies to minimize the release of dispersion of fouling organisms
into the water column.
To address ANS hull fouling concerns, EPA included the following requirements in the sVGP:
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