Wednesday, February 15, 2012
The Striped Bass
The Striped Bass, also known as the rockfish, were once
overfished, but then the state started to manage them, and implement laws to
return their populations to a sustainable level. The state was successful in
doing so, because now the Striped Bass Populations are the highest they've been
in decades. Striped bass larvae and postlarvae drift downstream toward
nursery areas located in river deltas and the inland portions of the coastal
sounds and estuaries. Juveniles typically remain in estuaries for two to four
years and then migrate out to the Atlantic Ocean. Striped bass spend the
majority of their adult life in coastal estuaries or the ocean, which is why so
many are found in the Chesapeake area. During different stages in their life
cycle, striped bass feed on zooplankton, fish larvae, insects, worms,
amphipods, Bay anchovy, spot, menhaden, herring, shad, white perch, and yellow
perch. This shows how important they are in the food web. They are a main
predator, and do not have very many predators
Because they are an important predator, and abundant in the Chesapeake Bay estuary they are a
keystone species.
Oysters!
Oysters are keystone animals in the Chesapeake Bay Estuary,
because they filter algae and
provide habitat and shelter for other animals and underwater plants. Therefore,
without them, the ecosystem would use an important part of its ecosystem, and
has been. While the bay's
salinity is ideal for oysters and the oyster fishery was at one time the bay's
most commercially viable, the same is not true for today. The Chesapeake used to be filled
with oysters, but due to overharvesting, and the introduction of Diseases such
as Dermo and MSX, and sediment pollution, their populations have become
dangerously low. Reef building, establishing protected sanctuaries, and
breeding for disease resistance may all be key to fostering a comeback of the
Bay’s native oysters.
Blue Claw Crabs
Blue Claw Crabs thrive in shallow warm water, which is why
the Chesapeake Bay is an ideal climate for them. Blue crab distribution varies with age, sex, and season:
Blue crabs tend to be abundant in shallow-water areas during warm weather; in
winter they are plentiful in the Bay's deeper portions. Males range farther up
into the fresher waters of the Bay and its rivers than females, who congregate
in saltier waters. Blue crabs are bottom-dwellers that use beds of submerged
aquatic grasses as sources of food, nursery habitat for young, and shelter
during mating, and molting. Blue crabs occupy a wide variety of habitats
throughout their life history. Offshore, high-salinity waters are used during
early larval stages. Larvae move into the estuary and use intertidal
marshes, sea grass beds, and soft-sediment shorelines as they grow. Crabs are
highly tolerant of temperature and salinity variations and can live in just
about any region of the Bay. Habitat loss and increased nutrient loading
present the greatest threats to the population. Red drum (not too many in the
Chesapeake area), croaker (amount varies from year to year), striped bass, and
other blue crabs prey upon blue crabs. The blue claw crab is a major part of
the Chesapeake Bay Ecosystem. Due to the economic and iconic value of the blue
crab, it is considered a keystone species influencing many aspects of the Bay's
ecosystem.
Friday, February 10, 2012
Osprey Eating Bass
Want to learn more?
Check out these short and interesting videos about the bay and the organisms that live there!
http://www.chesapeakebay.net/discover/bay101
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