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Counting at low concentrations: the statistical challenges of verifying ballast water discharge standards

Ecological Applications

By:
, , , and
DOI: 10.1890/11-1639.1

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Abstract

Discharge from the ballast tanks of ships is one of the primary vectors of nonindigenous species in marine environments. To mitigate this environmental and economic threat, international, national, and state entities are establishing regulations to limit the concentration of living organisms that may be discharged from the ballast tanks of ships. The proposed discharge standards have ranged from zero detectable organisms to <10 organisms/m3. If standard sampling methods are used, verifying whether ballast discharge complies with these stringent standards will be challenging due to the inherent stochasticity of sampling. Furthermore, at low concentrations, very large volumes of water must be sampled to find enough organisms to accurately estimate concentration. Despite these challenges, adequate sampling protocols comprise a critical aspect of establishing standards because they help define the actual risk level associated with a standard. A standard that appears very stringent may be effectively lax if it is paired with an inadequate sampling protocol. We describe some of the statistical issues associated with sampling at low concentrations to help regulators understand the uncertainties of sampling as well as to inform the development of sampling protocols that ensure discharge standards are adequately implemented.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Counting at low concentrations: the statistical challenges of verifying ballast water discharge standards
Series title:
Ecological Applications
DOI:
10.1890/11-1639.1
Volume
23
Issue:
2
Year Published:
2013
Language:
English
Publisher:
Ecological Society of America
Publisher location:
Ithaca, NY
Contributing office(s):
Western Fisheries Research Center
Description:
13 p.
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Ecological Applications
First page:
339
Last page:
351