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Danielle VernaAlaska Pacific University
Pacific Ballast Water Group - April 16, 2014
Influences of policy and vessel behavior
on the risk of ballast-borne marine species invasions in
coastal Alaska
Vector-based Invasion Risk
Ruiz & Carlton 2003
Dose-Response Relationship
Wonham et al. 2013
The expected number of species that will establish is the sum of the probability of each species
establishing
Species Assemblages
Holzer 2013
Application for Alaska
Ruiz et al. 2011
Last analysis of vessel arrival & ballast discharge data in AK was for 2003 – 2004 (McGee et al. 2006)
Hotspots of invasive species along the US west coast
High potential for coastwise transfer of species (secondary spread)
US BWM Policy
2004: USCG Mandatory BWM reporting Mandatory BWM
Exemptions: Crude oil tankers involved in
coastwise tradeTraveling within one Captain of the
Port ZoneDOD & USCG vessels
2008: EPA - Vessel General Permit Regulated Pacific nearshore voyages Mandatory management & record keeping for crude oil tankers involved in coastwise trade
Ballast in AK, 2005 - 2012
~72% of ballast discharge was sourced on the US west coast or
British Columbia
Tankers discharged ~88% of all ballast
Only 33% of reported ballast was managed
(BWE)
• 3,773 discharging arrivals
• 28,213 ballast tanks • 7.5 x107 MT of ballast• 67 ports/bays• 910 offshore lat/long
Ecoregions of Alaska
Spalding et al. 2007
92%
4%
2%
Ballast in AK, 2005 - 2012
Ballast Discharge Hotspots
Valdez
Red Dog
Southeast
Dutch Harbor
Afognak
Seward
Nikiski
Ballast Discharge Volume (MT)
Reported ballast discharge in AK, 2005 - 2012
2005 2006 2007 2008 2009 2010 2011 20120.0E+00
2.0E+06
4.0E+06
6.0E+06
8.0E+06
1.0E+07
1.2E+07
1.4E+07Overseas
Year
Ball
ast
Wate
r V
olu
me
(MT
)
2005 2006 2007 2008 2009 2010 2011 20120.0E+00
2.0E+06
4.0E+06
6.0E+06
8.0E+06
1.0E+07
1.2E+07
1.4E+07Overseas
Year
Ball
ast
Wate
r V
olu
me
(MT
)
Supply & Demand?
EPA VGP
Reported ballast discharge in AK, 2005 - 2012
Risk Assessment
Reporting increase, 2008 - 2009
Anchorage
Kodiak
Valdez
99% of the increase was to the Gulf of Alaska region
Coastwise ballast: 1095% increase
Overseas ballast: 17% increase
Valdez: 1170% increase in reported ballast discharge volume
47 to 258 reporting tankers
Valdez
Seward
Nikiski
Afognak
Dutch Harbor
Red Dog
Vessel Type & Exports
Red Dog Sources
18%
82%
Managed
Unmanaged
Dutch Harbor Sources
31%
69%
Managed
Unmanaged
Valdez Sources
67%
33% Managed
Unmanaged
Model risk as a function of environmental similarity, ballast water age, ballast water volume & species richness
Between source region and top 15 ports by volume
Risk Assessment 2009 - 2012
High-latitude risk assessments:
• Baltic Sea (Leppäkoski & Gollasch 2006)
• Canada (Chan et al. 2013)
• Norway (Ware et al. 2013)
Environmental Similarity‣ (positively correlated with risk)
1) Low non-adjacent ecoregion2) Medium adjacent ecoregion3) High same ecoregion
• A weighted average was applied to the proximity ranking based on the volume of ballast per source ecoregion
Risk Framework
Spalding et al. 2007
Ballast water age (negatively correlated with
risk)
Risk Framework
• Number of days between source and discharge date
Ballast water volume (positively correlated with
risk)
• Serves as a proxy for propagule pressure
• 0.1 correction factor applied to managed ballast to represent 90% efficacy rate of BWE (Ruiz & Reid 2007)
Risk Framework
Species Richness (positively correlated with risk)
• Number of ballast-borne marine invasive species per source ecoregion (Molnar et al. 2008)
Risk Framework
Environmen
tal Similarity
Age (days)
Corrected mean volume of ballast water
discharge: ecoregions & ports (log10MT)
Species Abundance
(1) Low < 1 > 10 < 2.6 < 110
(2) Medium 1 – 2 6 – 10 2.6 – 5.1 110 – 219
(3) High > 2 < 6 > 5.1 > 219
Risk Scale
Valdez, Nikiski, Drift River Terminal & Dutch Harbor may be hotspots for invasion
Risk to all ports was greatest from environmental similarity and ballast water volume
Past policy exemptions hindered monitoring and elevated risk
Results & Implications
Analysis of impacts from other management exemptions
(i.e. Captain of the Port Zones)
Finer-scale risk analysis
Focused management and survey efforts at source and discharge ports based on relative risk
Ballast water treatment systems
AK regulations?
Further Study
Increased Arctic vessel trafficNorthwest Passage & Northern
Sea RouteBering Strait bottleneck
Looking Ahead…
Port developmentOffshore oil & gas growth
Acknowledgements
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