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Freshwater.
It is an extremely valuable resource; especially on islands.
Streams are rare, life-supporting veins
that connect the land to the sea.
Pacific island streams are home to unique fish,
shrimp, and snails
found nowhere else in the world.
These species share a special life history. During their life-cycle they spawn
and lay their eggs in a stream.
The eggs hatch and the larvae wash out to the ocean.
After a period of up to several months, they return to the stream and begin an upstream migration to a place
where will spend the rest of their lives... growing and eventually reproducing.
This life-cycle is called an amphidromous life-cycle.
The native animals that live in Pacific island streams
have adapted to life and steep, fast-flowing environments.
For example, snails have streamlined shells that allow water to pass over them
without dislodging them.
And native gobies have specialized fins that form a type of sucking disk
used to climb waterfalls.
Water diversions,
runoff from poor land-use practices,
and introduced invasive species pose serious threats
to the native animals that depend on these streams.
These tiny little creatures are extremely important to tell us
the health of the stream as a whole, as well as the whole national park.
We're doing this monitoring in order to provide
an understanding
of what species live in this stream,
and how their populations are changing over time.
In Haleakala National Park
and Kalaupapa National Historical Park in Hawaii,
biologists monitor freshwater animals by moving slowly through designated areas of streams,
and systematically recording
the animals they observe.
In War in the Pacific National Historical Park on Guam,
and the National Park of American Samoa,
catch and release netting methods are used in combination with snorkeling surveys.
The field crew catches shrimp and fish in special nets,
identifies each animal,
and returns them to the stream unharmed.
If we know how these populations of stream animals are changing,
overtime we're hoping that we can provide clues and insights into
why they're changing.
And then hopefully find solutions to improve the environment in the long-run.