Conservation Issues Affecting the Mammal Community
at the Stellwagen Bank National Marine Sanctuary
The purpose
of this section is to provide an overview of conservation issues facing
the marine mammal community of the Stellwagen Bank National Marine Sanctuary.
This information will help to characterize baseline conditions affecting
marine mammals and aid in the development of future conservation and
research programs. An effort was made to cite references that pertain
to conditions effecting marine mammal populations found within the Gulf
of Maine, however in some instances, sources from outside the region
are cited to provide additional documentation in instances where local
research may be limited or the results are particularly helpful for
understanding a relevant issue.
In order
to facilitate the review of the conditions and activities effecting
the marine mammal community, each topic is presented under one of the
following general categories:
1. Direct
Effects Includes activities such as vessel strikes or entanglements
in fishing gear, which are likely to have immediate or short-term consequences,
and a source of the perturbation which is readily identifiable.
2. Indirect
Effects Such as the disposal of chemical wastes which may alter the
marine environment by contaminating prey species which in turn may effect
marine mammals upon consumption. It is the secondary, or indirect nature
of the impact on marine mammals that distinguishes this category of
effects.
3. Other
Effects A catch-all category including such phenomena as strandings,
which regardless of the cause, may have significant impacts on marine
mammal populations and represent important conservation issues for the
Sanctuary.
The purpose
of this organizational approach is not to suggest that one category
is more or less important to the conservation of marine mammal in the
Sanctuary. The intent here is simply to suggest some order to the myriad
of conditions effecting these populations as a lead in to ways to think
about establishing conservation programs. complex assessment of marine
conservation issues. Finally, in must be mentioned that in nature, marine
mammals are exposed to the cumulative effects of these activities, their
combined consequences are poorly understood and often difficult to quantify.
Effects which occur at a habitat, as opposed to species specific level
are often more difficult to detect and relate to a specific cause. Furthermore,
distinguishing changes which may occur due to human causes from those
which are a part of the natural variability in large marine ecosystems
is a complicated, expensive, and time consuming process.
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