Environmental Engineering Reference
In-Depth Information
for over half the nation's ports (Convention on Biological Diversity 2005). h e
increased eff ort placed on pest surveillance and delimitation surveys has resulted
in the development of some sophisticated approaches (Hayes
et al
. 2005; Gust and
Inglis 2006), but these are still based on sampling and detection at defi ned levels of
confi dence and can by no means guarantee fi nding all individuals. h e fact is that
many fi rst incursions are found simply by accident or enquiry, rather than by active
surveillance (e.g. Hay and Luckens 1987; Coutts and Forrest 2007).
Most reports of successful eradications of marine invaders acknowledge that a
major factor in their success is due to the populations in question being only recently
established or spatially restricted (Culver and Kuris 2000; Bax
et al
. 2002; Wotton
et al
. 2004; Anderson 2005). Once an introduced marine organism becomes geo-
graphically dispersed, management options become increasingly limited, and
invariably require expensive, long-term commitment (Sinner
et al
. 2000). For this
reason, surveillance eff orts must be coupled with incursion response systems that
can be rapidly deployed upon fi rst detection of new species (Wotton and Hewitt
2004). Swift response to the early detection of the black mussel
Mytilopsis adamsi
in Darwin, Australia resulted in the total eradication of this species in the region
(Bax
et al
. 2002). Similarly, when the invasive alga
C
.
taxifolia
was fi rst observed in
California in 2000, a rapid management response lead to its complete eradication
within 2 years (Anderson 2005). If newly established populations are allowed time
to reproduce the chances of eradication are greatly reduced. Continued inaction
following the initial introduction of
C
.
taxifolia
into the Mediterranean Sea in
1984 resulted in it becoming a major environmental and economic problem in the
region (Meinesz 1999).
Clarity regarding the overall desired management outcomes is critical prior to
the implementation of any post-border management, since this will infl uence the
scope, time-frame, and cost of the programme. For example, if the desired out-
come is eradication, then eff ective ongoing pest surveillance and vector manage-
ment are critical to success, while intensive management activities may only be a
short-term requirement (Coutts and Forrest 2007). Alternatively, a programme
aiming to control pest populations (e.g. to manage densities to a level that avoids
adverse eff ects) is likely to require a long-term commitment including ongoing
funding, with issues such as pest detection and management of re-invasion less of
a priority (Forrest 2007). In some circumstances, immediate containment or other
interim management actions may be necessary prior to the determination of fi nal
outcomes (Wotton and Hewitt 2004).
Following the identifi cation of a new incursion, it is crucial that a contingency
plan(s) be implemented in order to determine the most appropriate action(s) for a
rapid response. Ideally, such contingency planning would occur prior to an inva-
sion taking place (at least in the case of high-risk species). Such plans should defi ne
particulars such as which stakeholders require notifi cation, funding, and appro-
priate management options. In order for such management plans to be eff ective,
however, it is vital that decision makers be aware of all the tools available at their
