Ballast Water



Ships have used versions of ballast for centuries, using rocks, earth or other heavy objects to balance the vessel, maintain stability and set buoyancy. However, with the invention of steel-hulled ships, vessels began to have the ability to use readily available seawater as ballast internally, without degrading the wood that had been used in ship construction in the past. With this new option becoming increasingly popular in the latter half of the 19th century, the likelihood for water transfer between areas increased dramatically. Today, most commercial ships use ballast water, typically loading ballast when offloading cargo and discharging ballast when onloading cargo.  However, when loading ballast, small organisms are often also brought onboard with the water. If unmanaged,  water can then be transferred to areas and discharged with viable organisms in the effluent. Organisms that are then deposited can cause harm to native flora and fauna in the new area they inhabit. 



Ballast water is one of the top two means of non-native species transfer throughout the world. After being transferred, species have been known to have negative impacts on the cultural, socioeconomic and environmental value of areas where they begin to inhabit. Because Hawaiʻi is already the state with the most aquatic invasive species in the US, managing ballast water in a responsible way is essential to preventing further non-native species introductions to the State. Many Hawaiʻi agencies have recognized the importance of ballast water management to limit non-native species introductions and its importance has been cited as a part of many Hawaiʻi agency plans that include; the Hawaiʻi AIS Management Plan, Hawai`i Interagency Biosecurity Plan, Hawaiʻi Ocean Resource Management Plan and the Hawaiʻi DAR 30×30 Target for Ocean Management

Ballast water has been studied extensively worldwide, and numerous invasive species are attributed to this mode of introduction. Examples include zebra mussels in the Great Lakes and their negative impacts on commercial and recreational fisheries and damages to city water supplies; dinoflagellates causing red tides and fish kills in Australia and elsewhere; cholera bacteria causing epidemics in South America; green crabs destroying mollusk and crustacean populations in areas it has invaded.



Passed into law on August 10, 2017, Hawaiʻi Administrative Rules Ch. 13-76 address the need for regulation of ballast water in the State and help to regulate ballast water in concurrence with federal regulations and in cooperation with the United States Coast Guard.  

Hawaiʻi State Administrative Rules Ch. 13-76 require vessels to: 

            • Submit a Ballast Water Management Report to the State of Hawaiʻi DLNR 24 hours prior to arrival in port and can be downloaded at National Ballast Information Clearinghouse. Forms can be emailed to [email protected]
            • Submit an amended form with corrected information, if needed, before leaving state waters
            • Have a USCG ballast water management plan onboard 
            • Have 2 years of ballast water history maintained on board 
            • Manage ballast water in an approved method before discharge 
            • Allow DLNR to board the vessel to inspect documentation and take samples of sediment and ballast water to ensure compliance

Acceptable options for ballast water management:  

    • Empty/Refill Exchange: pumping the ballast tank or tanks and refilling the tank with mid-ocean waters at least 200 nautical miles from any coast.          
    • Flow through exchange: pumping in mid-ocean water, at least 200 nautical miles from any coast, at the bottom of the tank and continuously overflowing the tank from the top until three full volumes of the ballast water tank capacity have been changed.         
    • Onboard Treatment: Use of a properly functioning treatment system approved by the United States Coast Guard and designed to kill all living organisms in the ballast water. 
    • Freshwater: Use of ballast water from a municipal water supply from the US or Canada.  
    • Sealed tanks: Use of ballast water in sealed tanks incapable of discharging ballast water.


International Maritime Organization (IMO) Guidelines D-2 Regulations for BW Management System Performance Standards specify the number of viable cells per microorganism category permitted in ballast water discharge (Table 1). Currently, the 10-50 μm size class are enumerated using epifluorescence microscopy to determine compliance. However, this method requires technically trained staff, long hours of enumeration, and expensive, bulky instrumentation and would be unfeasible to perform during routine BW compliance monitoring inspections. DLNR investigated a new rapid assessment tool, which is purported to simplify BW discharge compliance monitoring for the 10-50 μm size class. The technology utilizes phytoplankton fluorescence as a proxy for cell viability and concentration. 


Table 1. Summary of IMO D-2 Regulations.

Microorganism Category IMO Standards
Zooplankton >50 μm < 10 viable organisms/m3
Phytoplankton 10-50 μm < 10 viable organisms/mL
Vibro cholerae <1 colony forming units/100 mL
Escherichia coli <100 colony forming units/100 mL
Intestinal Enterococci <100 colony forming units/100 mL


For questions related to ballast water or hull fouling (vessel biofouling), please contact The Hawaiʻi Ballast Water and Hull Fouling Team: [email protected]