MANGANESE NODULES
40
set aside for conservation. This approach should take into
account all different marine uses (e.g. extractive industries,
fisheries, navigation, cabling, tourism) and will enable asso-
ciated impacts to be considered and managed cumulatively.
• Evaluating the location of discharges to ensure minimal im-
pact on ecosystems. Discharging at depth reduces the risk
to surface or pelagic animals, but may have effects on ben-
thic fauna if discharges spread over a wider area than the
mining sediment plume. In very deep water, discharging
near the sea-floor may not be technologically or econom-
ically feasible. The use of diffusers can aid dispersal, and
oceanographic considerations are important regarding the
direction of flow and the direction of discharge.
• Considering animal relocation, if there are populations of
rare, endemic (found nowhere else), or highly endangered
species. Experience from the CCZ indicates that there can be
high diversity and abundance at individual sites and consid-
erable variability in species distributions over hundreds of
kilometres (Smith
et al
. 2008). However, such an approach
might be less conservation-effective and less cost-efficient
than designating Marine Protected Areas (MPAs).
• Employing reserve networks, such as Marine Protected Areas.
These networks are recommended by many scientists and
managers as effective means of protecting fauna from impacts
of fishing or mining. This approach is often adopted at a na-
Connectivity
Biodiversity
Replication
Viability
Representivity
Sustainable use
Ensure maintenance of the ecosystems
Ensure ecological connectivity between sites
Conserve multiple sites, not just one
Ensure the size and spacing of reserves is adequate
Multiple sites must contain a wide range of species and functions to allow for
uncertainty or natural variation in populations
Include other potential uses in designing the areas (e.g. shing)
Key elements of marine reserve design
Figure 21 Key element of marine reserve design (ISA, 2008).
tional level and sometimes at a much larger spatial scale than a
single mining operation. Inter-governmental involvement might
be required. Whether or not an MPA network approach is war-
ranted may depend on the proportion of sites that are consid-
ered commercially viable in relation to the total number of sites
present, and whether or not the remaining untouched sites are
representative of the sites to be mined. Ideally, the design of
MPAs andMPA networks should follow four sequential steps: (1)
evaluation of conservation needs; (2) definition of the objectives
for establishing the MPAs; (3) integration of information on the
biological characteristics (e.g., life histories, dispersal patterns,
species distributions) and habitat distribution of the managed
ecosystem; and (4) selection of suitable sites to serve as MPAs.
The key design elements of marine reserves listed by the Part-
nership for Interdisciplinary Studies of Coastal Oceans (PISCO
2007) provide a useful starting point for considering marine spa-
tial planning and MPA planning (Figure 21).
Temporal measures: The time scales of nodule growth and fau-
nal recovery in the abyssal deep sea almost certainly make con-
sideration of short time scale measures impractical. Measures
to rehabilitate degraded areas or encourage longer-term faunal
recruitment are much less likely to be effective than spatial man-
agement approaches
