A new USCG analysis shows that the number of vessels discharging unmanaged ballast water within 12 nm has reduced in the last year, but it is uncertain if this is linked to ballast water best management practices (BMP) recommended by USCG in 2019.
The new analysis follows the release of MSIB 07-19 by USCG Office of Operating and Environmental Standards (CG-OES) on September 6, 2019, informing vessel representatives of the outbreak of stony coral tissue loss disease (SCTLD) in Florida and throughout the greater Caribbean region. MSIB 07-19 reminded vessel representatives of the required ballast water management practices and recommended additional voluntary best management practices that could be employed to reduce the potential for transport of organisms in ballast water.
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Now, the Office has published an analysis of the effect of MSIB 07-19 on the discharge of unmanaged ballast water in US waters in Southeast Florida and the Caribbean. For the 12 months following the release of MSIB 07-19, the CG-OES, the National Ballast Information Clearinghouse (NBIC), and the EPA Office of Oceans, Wetlands and Watersheds analyzed the differences in the number and volumes of unmanaged ballast water discharged in US waters in the region, compared to the average and ranges for the same months during the six years prior to release.
As revealed, over the 12 months following the MSIB, the number of vessels discharging unmanaged BW within 12 Nm was lower than the average number doing so for the 6 years prior to the MSIB. However, it was not possible to exclusively attribute the decrease to vessels following the voluntary practices recommended in the MSIB. Two other factors likely contributed to the decrease in the discharge of unmanaged ballast water during the year following release of the MSIB:
- the steady increase in the use of onboard ballast water management systems to treat ballast water prior to discharge, and
- the general decrease in vessel arrivals and ballast water discharges due to the effects of the Covid-19 pandemic on shipping.
Stony coral tissue loss disease is a lethal coral disease first detected in the vicinity of Miami, in 2014 and has since spread throughout the greater Caribbean region, with a devastating impact on many species of stony coral in the region, including some considered threatened. While there is no definitive identification of a causal agent, evidence suggests one or more bacteria may be involved. The disease can be transmitted through water, as well as through direct contact between corals. Ballast water of ships has been suggested as one possible mechanism for spread of the disease.
It is reminded that vessels that have not yet reached their compliance dates for meeting the ballast water discharge standard must conduct ballast water exchange beyond 200 nautical miles of shore prior to discharging ballast water in US waters. However, the regulations provide exemptions from this requirement for circumstances where conducting exchange would endanger the vessel, and for circumstances where a vessel’s route does not take it beyond 200 nm for a long enough duration to complete an exchange in accordance with the regulations.
In the latter cases, although the specific pathogens causing SCTLD are not known, and the transmission of SCTLD in ballast water has not yet been demonstrated, the MSIB recommended vessel masters conduct BWE beyond 50 nm of shore, to reduce the likelihood that SCTLD might be transported between locations in unmanaged ballast water.