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PROPOSED
MEASURES: NATIVE SPECIES
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Population trends
(increasing, decreasing, or stable) and conservation status (secure
or at risk) for a variety of key or well known marine species. Data
on marine species are extremely sparse, and thus the choice of possible
species for reporting is extremely limited. Information on a broader
range of species should be obtained to complement the data presented
here on well-known or commercially important species.
Marine Mammals
(Fig. 1)
Seabirds (Fig.
2)
Sea Turtles
(Fig. 3)
Commercially
Important Fish (Fig. 4)
One third of marine
mammal stocks are considered at risk, and population trends for almost
80 percent of all stocks are unknown.
Only 15 percent
of seabird populations are considered at risk. Population trends are
unknown for nearly 50 percent of Alaskan species and more than 25 percent
of East Coast species. The number of seabird populations that are either
stable or increasing exceeds the number that are declining.
All sea turtle
populations are classified as at risk. Of those found in U.S. waters
whose trends are known, two-thirds of populations are increasing or
stable.
One-third of the
300 commercially important fish stocks whose status is known are either
overfished or approaching an overfished condition. The current status
of more than 60 percent (544 stocks) of commercially fished stocks is
unknown.
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Marine Mammals (1) Technical
Note |
Seabirds
(2) Technical
Note |
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| Source:
NOAA National Marine Fisheries Service, The Nature Conservancy and
the network of State Heritage Programs |
Source:
Andrews, 1990; Byrd, et al, 1998; Carter, et al, 1995; Gilligan,
et al, 1994; Hatch, 1993, 1994; Smith et al, 1997; The Nature Conservancy
and the network of Heritage Programs |
| Marine mammals
include dolphins, whales, seals, manatees, walruses, and sea lions.
Sixty-two species, with a total of 143 separate populations or stocks,
are found in U.S. waters. |
| Sea
Turtles (3) Technical
Note |
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Six
species of sea turtles frequent U.S. waters. There are 10 separate
populations, including 5 in the Pacific Ocean and 5 in the Atlantic
Ocean or Gulf of Mexico. All are listed as threatened or endangered
by the National Marine Fisheries Service. |
Stocks
of Commercially Important Fish, 1998 (4)
Technical Note
Source:
NOAA National Marine Fisheries Service |
| Source:
NOAA National Marine Fisheries Service, The Nature Conservancy and
the network of Heritage Programs |
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STATUS
OF DATA & OTHER NOTES
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No consistent
and comprehensive national information is available for the majority
of marine species. Even for fish, the status of more than half
of the stocks is unknown.
Conservation
status (shown here as "at risk" or "apparently secure") is assessed
by The Nature Conservancy (TNC) using a ranking system that considers
the numbers of individuals and groups within a species. The TNC
system has five categories ranging from "critically imperiled"
to "demonstrably secure." For this report, these categories were
collapsed into the two ratings shown here.
It is possible
to know the status of a speciesū whether it is depleted or relatively
abundantū without knowing whether the population is increasing,
decreasing, or stable. Although the populations of some "at risk"
species are growing, their status is often still precarious. In
addition, some species can proliferate beyond their historical
limits, creating ecological imbalances.
Please see
the Technical
Notes for additional information.
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