117
The Economy and Human Health
Social and economic impacts are linked to invasive species
altering fisheries, aquaculture, tourism, and marine infrastructure activities. Human health is also impacted, when the
consequence of these alterations results in lost revenue and,
potentially, a direct decrease in human health (Bax et al.
2001).
The economy drives the exchange of goods across the
globe via shipping routes and trade and with it come new
NIS. In some instances, NIS have negative economic impacts
by altering ecosystems and reducing the stocks of exportable
fish and shellfish through competition and disease. Few studies focus on the economic impacts of aquatic species alone
and even fewer separate out marine from freshwater species
impacts. In a recent case study, Ünal and Bodur (2017) investigated the negative impacts of Silver-cheeked toadfish
Lagocephalus scleratus on small-scale fisheries in the eastern Mediterranean Sea. Marine invasions pose an additional
challenge because of the widely dispersing planktonic larvae
of some marine species (Thresher and Kuris 2004).
The European green crab Carcinus maenas, ranked in the
IUCN list of the ‘world’s worst invasive alien species’ (Lowe
et al. 2004) has had quite an economic impact in North
America since emerging from its native European range over
200 years ago (Carlton and Cohen 2003). The estimated
annual losses to shellfisheries on the East Coast of the United
States due to predation by C. maenas alone range from $14.7
to $18.7 million a year and sum up to $805.9 million during
the period from 1975 to 2005 (Abt Associates Inc. 2008). In
addition to loss of profit from shellfish sales, green crabs are
also responsible for the loss of eelgrass in restoration projects through bioturbation activities such as foraging and burrowing (Davis et al. 1998). The associated costs from these
activities range from $60,150 to $77,433 as an estimate for
the year 2006 (Abt Associates Inc. 2008). Apart from the
costs associated with direct shellfish predation and eelgrass
restoration projects, there are also projected costs for handling further losses from the NIS. Expenditures for a proposed monitoring and control program to the US
Environmental Protection Agency would cost $285,000 per
year (Abt Associates Inc. 2008). The European shore crab is
just one NIS, in one country and calculations are based on
only the known impacts. Carlton (1999) and others demonstrated through the European shore crab that the economic
cost of a single NIS can be quite significant, highlighting the
need for effective control and management implementation.
Keller et al. (2011) highlight the possibility that there may be
economic benefits in some cases. The release of the Red king
crab Paralithodes camtschaticus into the Barents Sea and
subsequent expansion into the Norwegian coast provided an
income of over 9 million EUR for fisherman (Galil et al.
2009). Other edible NIS used in fisheries or aquaculture
include the fish Planiliza haematocheila, Saurida lessepsianus, Siganus luridus, S. rivulatus, the molluscs Ensis directus, Mercenaria mercenaria and Aerococcus viridans var.
homari (Katsanevakis et al. 2014).
While known impacts of NIS can be calculated to the dollar, other factors may not have a monetary label, especially
those concerning human health. Lafferty and Kuris (1996)
describe the risk that the Chinese mitten crab in California
presents as a second intermediate host for the Oriental lung
fluke Paragonimus westermani, which can cause paralysis in
humans. If the mitten crab becomes widely abundant, it may
serve as a suitable host for the native North American lung
flukes and increase the potential for infection in humans
(Lafferty and Kuris 1996).
Management and Policy
As Thresher and Kuris (2004) summarize, there are management efforts in outbreaks across the globe, from the marine
alga Caulerpa taxifolia in California, the Mediterranean Sea
and Australia (Meinesz et al. 2001; Cheshire et al. 2002;
Williams and Grosholz 2002) to the Asian whelk Rapana
venosa in the Chesapeake Bay (Mann and Harding 2000)
and the Asian mussel Perna viridis in Cairns, Australia
(Thresher and Kuris 2004). These examples illustrate that
marine invasions are truly a global challenge. In meeting this
challenge, the study highlights four key differences between
management in marine and terrestrial invasion approaches.
The first is that the ocean is perceived as an open system and
that, due to global patterns of circulation, pelagic larvae and
large-scale migrations, local eradication efforts are insignificant. The open nature of the ocean establishes a defeatist attitude among public managers. Another challenge to marine
invasions is who should bear the burden of cost. The benefits
of management actions can be widespread and, therefore,
which parties should be involved in paying for them can
become convoluted. Furthermore, the public perceives the
ocean and open coastline to be pristine, allowing invasions to
go largely unnoticed by the public. Thus, public awareness
typically does not arise until the later stages of the invasion
process (expansion and persistence), while at the same time
containment and other management efforts grow increasingly difficult (Fig. 3). Finally, scientific literature on the
biology of most marine taxa is limited, making decisions and
predicting outcomes of management practices difficult
(Thresher and Kuris 2004). Despite these additional challenges in managing marine invasions, there have been
approaches developed which have produced mixed results.
Lovell et al. (2006) highlights some of the policies
developed to limit the spread of NIS. Two main approaches
to international policy have been to focus on shipping vectors as a means of distribution, and by limiting the amount
How Do They Do It? – Understanding the Success of Marine Invasive Species
The Economy and Human Health
Social and economic impacts are linked to invasive species
altering fisheries, aquaculture, tourism, and marine infrastructure activities. Human health is also impacted, when the
consequence of these alterations results in lost revenue and,
potentially, a direct decrease in human health (Bax et al.
2001).
The economy drives the exchange of goods across the
globe via shipping routes and trade and with it come new
NIS. In some instances, NIS have negative economic impacts
by altering ecosystems and reducing the stocks of exportable
fish and shellfish through competition and disease. Few studies focus on the economic impacts of aquatic species alone
and even fewer separate out marine from freshwater species
impacts. In a recent case study, Ünal and Bodur (2017) investigated the negative impacts of Silver-cheeked toadfish
Lagocephalus scleratus on small-scale fisheries in the eastern Mediterranean Sea. Marine invasions pose an additional
challenge because of the widely dispersing planktonic larvae
of some marine species (Thresher and Kuris 2004).
The European green crab Carcinus maenas, ranked in the
IUCN list of the ‘world’s worst invasive alien species’ (Lowe
et al. 2004) has had quite an economic impact in North
America since emerging from its native European range over
200 years ago (Carlton and Cohen 2003). The estimated
annual losses to shellfisheries on the East Coast of the United
States due to predation by C. maenas alone range from $14.7
to $18.7 million a year and sum up to $805.9 million during
the period from 1975 to 2005 (Abt Associates Inc. 2008). In
addition to loss of profit from shellfish sales, green crabs are
also responsible for the loss of eelgrass in restoration projects through bioturbation activities such as foraging and burrowing (Davis et al. 1998). The associated costs from these
activities range from $60,150 to $77,433 as an estimate for
the year 2006 (Abt Associates Inc. 2008). Apart from the
costs associated with direct shellfish predation and eelgrass
restoration projects, there are also projected costs for handling further losses from the NIS. Expenditures for a proposed monitoring and control program to the US
Environmental Protection Agency would cost $285,000 per
year (Abt Associates Inc. 2008). The European shore crab is
just one NIS, in one country and calculations are based on
only the known impacts. Carlton (1999) and others demonstrated through the European shore crab that the economic
cost of a single NIS can be quite significant, highlighting the
need for effective control and management implementation.
Keller et al. (2011) highlight the possibility that there may be
economic benefits in some cases. The release of the Red king
crab Paralithodes camtschaticus into the Barents Sea and
subsequent expansion into the Norwegian coast provided an
income of over 9 million EUR for fisherman (Galil et al.
2009). Other edible NIS used in fisheries or aquaculture
include the fish Planiliza haematocheila, Saurida lessepsianus, Siganus luridus, S. rivulatus, the molluscs Ensis directus, Mercenaria mercenaria and Aerococcus viridans var.
homari (Katsanevakis et al. 2014).
While known impacts of NIS can be calculated to the dollar, other factors may not have a monetary label, especially
those concerning human health. Lafferty and Kuris (1996)
describe the risk that the Chinese mitten crab in California
presents as a second intermediate host for the Oriental lung
fluke Paragonimus westermani, which can cause paralysis in
humans. If the mitten crab becomes widely abundant, it may
serve as a suitable host for the native North American lung
flukes and increase the potential for infection in humans
(Lafferty and Kuris 1996).
Management and Policy
As Thresher and Kuris (2004) summarize, there are management efforts in outbreaks across the globe, from the marine
alga Caulerpa taxifolia in California, the Mediterranean Sea
and Australia (Meinesz et al. 2001; Cheshire et al. 2002;
Williams and Grosholz 2002) to the Asian whelk Rapana
venosa in the Chesapeake Bay (Mann and Harding 2000)
and the Asian mussel Perna viridis in Cairns, Australia
(Thresher and Kuris 2004). These examples illustrate that
marine invasions are truly a global challenge. In meeting this
challenge, the study highlights four key differences between
management in marine and terrestrial invasion approaches.
The first is that the ocean is perceived as an open system and
that, due to global patterns of circulation, pelagic larvae and
large-scale migrations, local eradication efforts are insignificant. The open nature of the ocean establishes a defeatist attitude among public managers. Another challenge to marine
invasions is who should bear the burden of cost. The benefits
of management actions can be widespread and, therefore,
which parties should be involved in paying for them can
become convoluted. Furthermore, the public perceives the
ocean and open coastline to be pristine, allowing invasions to
go largely unnoticed by the public. Thus, public awareness
typically does not arise until the later stages of the invasion
process (expansion and persistence), while at the same time
containment and other management efforts grow increasingly difficult (Fig. 3). Finally, scientific literature on the
biology of most marine taxa is limited, making decisions and
predicting outcomes of management practices difficult
(Thresher and Kuris 2004). Despite these additional challenges in managing marine invasions, there have been
approaches developed which have produced mixed results.
Lovell et al. (2006) highlights some of the policies
developed to limit the spread of NIS. Two main approaches
to international policy have been to focus on shipping vectors as a means of distribution, and by limiting the amount
How Do They Do It? – Understanding the Success of Marine Invasive Species