NMFS Biological Opinion on U.S. Navy training ... - Govsupport.us

FINAL PROGRAMMATIC BIOLOGICAL OPINION ON U.S. NAVY ACTIVITIES IN THE HAWAII RANGE COMPLEX 2008-2013
affect the distribution of cephalopod populations, but would not reduce the number or density of cephalopod
populations. If, however, cephalopod populations collapse or decline dramatically, sperm whale populations are
likely to collapse or decline dramatically as well.
The response of North Atlantic right whales to changes in the North Atlantic Oscillation also provides insight into
the potential consequences of a changing climate on large whales. Changes in the climate of the North Atlantic have
been directly linked to the North Atlantic Oscillation, which results from variability in pressure differences between
a low pressure system that lies over Iceland and a high pressure system that lies over the Azore Islands. As these
pressure systems shift from east to west, they control the strength of westerly winds and storm tracks across the
North Atlantic Ocean. The North Atlantic Oscillation Index, which is positive when both systems are strong
(producing increased differences in pressure that produce more and stronger winter storms) and negative when both
systems are weak (producing decreased differences in pressure resulting in fewer and weaker winter storms), varies
from year to year, but also exhibits a tendency to remain in one phase for intervals lasting several years.
Sea surface temperatures in the North Atlantic Ocean are closely related to this Oscillation and influences the
abundance of marine mammal prey such as zooplankton and fish. In the 1970s and 1980s, the North Atlantic
Oscillation Index have been positive and sea surface temperatures increased. These increased are believed to have
produced conditions that were favorable for the copepod (Calanus finmarchicus), which is the principal prey of
North Atlantic right whales (Conversi et al. 2001) and may have increased calving rates of these whales (we cannot
verify this association because systematic data on North Atlantic right whale was not collected until 1982; Greene et
al. 2003). In the late 1980s and 1990s, the NAO Index was mainly positive but exhibited two substantial, multi-year
reversals to negative values. This was followed by two major, multi-year declines in copepod prey abundance
(Pershing et al. 2001, Drinkwater et al. 2003). Calving rates for North Atlantic right whales followed the declining
trend in copepod abundance, although there was a time lag between the two (Greene et al. 2003).
Although the NAO Index has been positive for the past 25 years, atmospheric models suggest that increases in ocean
temperature associated with climate change forecasts may produce more severe fluctuations in the North Atlantic
Oscillation. Such fluctuations would be expected to cause dramatic shifts in the reproductive rate of critically
endangered North Atlantic right whales (Drinkwater et al. 2003; Greene et al. 2003) and possibly a northward shift
in the location of right whale calving areas (Kenney 2007).
Changes in global climatic patterns are also projected to have profound effect on the coastlines of every continent by
increasing sea levels and increasing the intensity, if not the frequency, of hurricanes and tropical storms. Based on
computer models, these phenomena would inundate nesting beaches of sea turtles, change patterns of coastal erosion
and sand accretion that are necessary to maintain those beaches, and would increase the number of turtle nests that
are destroyed by tropical storms and hurricanes. Further, the combination of increasing sea levels, changes in
patterns of coastal erosion and accretion, and changes in rainfall patterns are likely to affect coastal estuaries,
submerged aquatic vegetation, and reef ecosystems that provide foraging and rearing habitat for several species of
sea turtles. Finally, changes in ocean currents associated with climate change projections would affect the migratory
patterns of sea turtles. The loss of nesting beaches, by itself, would have catastrophic effect on sea turtles
populations globally if they are unable to colonize any new beaches that form of if the beaches that form do not
provide the sand depths, grain patterns, elevations above high tides, or temperature regimes necessary to allow turtle
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