VI. Information Gaps
Although we know a great deal about many of the pinnipeds, because they
are more easily observed on land and more easily handled for sampling, we
know very little about most cetaceans. Those species that occur near shore
and are easily caught and tagged (e.g. bottlenose dolphin) have been reasonably
well studied. The ecology of large whales and pelagic dolphins has only
recently been studied with any rigor, because of the use of new techniques
for marking (e.g. VHF and satellite tagging), biopsy sampling
(to determine sex, pollutant levels, genetic relationships), and photo-identification of individuals (e.g. Calambokidis et al.
1990, Ford et al. 1994). We know very little about which habitats are most
critical for the survival of cetaceans. We recognize that pinnipeds require
some terrestrial locations for rest and reproduction, but the aquatic areas
needed for feeding are only now being determined.
One of the most important process-based ecological questions that needs
study is the relationship between the prey resources and the marine mammal
populations. Many of the species using the MBNMS are here because of the
prey resources. We need to understand what constitutes sufficient prey resources
in temporal and spatial scales, and understand how changes in prey resources
affect marine mammal populations. These findings should be incorporated
into fisheries management decisions when fishery quotas are being determined.
We know very little about the marine mammal ecology at the northern and
southern borders of the MBNMS, primarily because it is some distance from
the ports and research institutes that border Monterey Bay. More effort
should be extended offshore and at the edges of the MBNMS.
Acoustic studies of marine mammal vocalizations may be greatly enhanced
by access to continuous sound recordings from fixed acoustic arrays, such
as those recently declassified by the military.
The recent ATOC controversy (Acoustic Thermometry of Ocean Climate, see
ARPA/NOAA 1995) has heightened our concerns regarding the effects of sound
on marine organisms, especially species that use sound for navigation, communication,
and localizing prey (e.g. cetaceans). One of the most understudied pollutant
is noise, and its effects may be more far ranging than we realize. The main
purpose the ATOC project, i.e to measure ocean warming as an indicator of
global warming, should be addressed in marine mammal research as well.Long-term changes in population distribution and abundance may provide strong indicators
of ocean climate change via impacts to prey or other resources.
Next - Section VII. Selected Marine Mammal Resources
Marine Mammals Table of Contents