The nature and extent of organisms in vessel sea-chests: A protected mechanism for marine bioinvasions

A total of 150 different organisms, including one plant species and 12 animal phyla were identified from sea-chests of 42 vessels visiting or operating in New Zealand between May 2000 and November 2004. Forty-nine percent of organisms were sessile, 42% mobile adults and the remaining 9% sedentary. Decapods were the most represented group with 19 species present among 79% of vessels. Forty percent of organisms were indigenous to New Zealand, 15% introduced, 10% non-indigenous, and 35% of unknown origin. Sea-chests have the potential to (1) transfer non-indigenous organisms between countries across oceanic boundaries; and (2) disperse both indigenous and introduced organisms domestically. The occurrence of adult mobile organisms is particularly significant and indicates that sea-chests may be of greater importance than ballast water or hull fouling for dispersing certain marine species. These findings emphasise the need to assess and manage biosecurity risks for entire vessels rather than different mechanisms (i.e., ballast water, hull fouling, sea-chests, etc.) in isolation.     

Potential ramifications of the global economic crisis on human-mediated dispersal of marine non-indigenous species

The global economy is currently experiencing one of its biggest contractions on record. A sharp decline in global imports and exports since 2008 has affected global merchant vessel traffic, the principal mode of bulk commodity transport around the world. During the first quarter of 2009, 10% and 25% of global container and refrigerated vessels, respectively, were reported to be unemployed. A large proportion of these vessels are lying idle at anchor in the coastal waters of South East Asia, sometimes for periods of greater than 3 months. Whilst at anchor, the hulls of such vessels will develop diverse and extensive assemblages of marine biofouling species. Once back in service, these vessels are at risk of transporting higher-than-normal quantities of marine organisms between their respective global trading ports. We discuss the potential ramifications of the global economic crisis on the spread of marine non-indigenous species via global commercial shipping.     

Introduced marine species: Management arrangements of consideration for the Torres Strait

Introduced marine species (IMS) can have significant impacts on economic, ecological, social and cultural aspects of coastal marine environments. There is, therefore, a need to minimise these impacts through the implementation of comprehensive and consistent management strategies and monitoring processes that work towards preventing introductions, detecting introductions if they were to occur and managing incursions should they be detected. There is also the need to ensure that approaches taken are comparable to provide consistency of IMS management effort, particularly across areas that are multi-jurisdictional (e.g. spanning State or Territory borders).     

Mesocosm experiments for evaluating the biological efficacy of ozone treatment of marine ballast water

Ballast water is a major pathway for the transfer of non-indigenous species in aquatic environments. The objectives of this study were to determine the ability of ozone to reduce the numbers of a spectrum of marine organisms collected from Puget Sound, Washington in replicated mesocosm (280 l) experiments, and estimate the minimum ozone concentrations as measured by total residual oxidant (TRO) required to reduce organism densities. Ozone treatment was effective in removing bacteria, phytoplankton, and mesozooplankton with initial TRO concentrations of 2–5 mg l⁻¹ as Br₂. Persistence of TRO resulted in an extended period of toxicity and cumulative mortality. TRO decay allowed bacteria populations to multiply when TRO levels fell below 0.5–1.0 mg l⁻¹ as Br₂. Phytoplankton chlorophyll a concentrations were rapidly reduced by ozone treatment and did not increase in any treatments or controls because of lack of light. Overall mesozooplankton viability was rapidly reduced by 90–99% in treatment TRO levels above 1.85 mg l⁻¹ as Br₂. Our study outlines novel protocols that can be used for testing different potential ballast water treatment systems in replicated and controlled mesocosm experiments.