Oceans and Estuaries

11.2 Notes - Life in Bays and Estuaries

​Estuaries and the wetlands in them are where the young of our most important Gulf species live before becoming adults.

​

Young fish, shrimp, and small crabs hide from predators and find food here.

​

Estuaries as Nurseries

Multiple Choice

The estuaries and the wetlands are where the _________ of our most important Gulf species live before becoming __________.

• adults / young

• young / adults

• eggs / dead

• really old / old

Multiple Choice

Fish, shrimp, and small crabs hide from predators and find food here ________?

• rivers & streams

• lakes & ponds

• rivers & aquifers

• estuaries & wetlands

Estuary Food Webs

• ​Sediments from river inflows carry tiny bits of detritus and nutrients

• Detritus and nutrients feed plants and plankton

• Freshwater grasses near river inflows due to low salinity

• Seagrasses replace freshwater grasses in saltier parts of estuary

Multiple Choice

Detritus and nutrients are carried by ________ from river inflows.

• sediments

• seagrass

• freshwater grasses

• fishes

Multiple Choice

Detritus and nutrients are food for ________ .

• seabass

• spotted seatrout

• plankton

• red drum

Estuary Food Webs

• Grasses grow in large areas or clumps called beds that provide food for zooplankton

• Grasses provide structure and habitat to hide from predators

• They also act as biofilter by helping settle out sediments

• More than 90% of the seagrass beds in Galveston Bay have been destroyed

• 80% of Texas’ remaining seagrass habitat is located in the Laguna Madre

Multiple Choice

Less than 70% of the seagrass beds in Galveston Bay have been destroyed.

• True

• False

Multiple Choice

80% of Texas' remaining seagrass habitat is located in ________ ?

• Corpus Christi

• Laguna Madre

• Port Aransas

• Gulf of Mexico

Estuary Food Webs

• Oysters filter plankton from water and build reefs

• Reefs provide shelter from predators for small fish and crustaceans which includes such animals as crabs, lobsters, crayfish, shrimps, prawns, krill, woodlice, and barnacles

• Predators include spotted trout and red drum

​Spotted Seatrout

• Lay eggs in seagrass to hide from predators

• Young grow up in bays eating zooplankton then graduate to eating small fish and shrimp

• Feed mainly around seagrass and oyster reefs

• Move out to warmer waters of Gulf during winter

​

Predator Adaptations

Multiple Choice

 The Spotted Seatrout feeds mainly around seagrass and _________.

• coral reefs

• mussel reefs

• oyster reefs

​Red Drum

• Adults live in Gulf

• Lay eggs and tidal currents flow will carry the eggs into bay

• Aggressive feeders that grow fast

• Mature in 3-6 years then move back out into Gulf

​

Predator Adaptations

Multiple Choice

Red Drum fish mature in 3-6 years then move back out into ______.

• Gulf

• River

• Bay

• Estuary

• ​​Oysters are filter feeders, they filter out detritus, sediments and pollutants, cleaning the water in bays and estuaries

• When a large number of oysters join together they create a massive underwater structure called an “oyster reef.” 

• Oyster reefs provide habitat for tiny periphyton and zooplankton, macroinvertebrates such as crabs, small fish, and larger fish looking for crabs and smaller fish to eat. 

• An oyster reef creates an entire aquatic community.

Importance of Oysters​

​

Multiple Choice

When a large number of oysters join together they create a massive underwater structure called an ________.

• coral reef

• oyster reef

• mussel reef

• pearl reef

• Without enough freshwater, sediments, and nutrients, the estuaries could not function as nursery grounds for the fish and shellfish we like to catch and eat. 

  ​

• Marine biologists have determined that 90-95% of all commercially and recreationally important species are found in our estuaries at some stage of their life cycle.

​

Importance of Freshwater Inflow​ and Nutrient Rich Sediment

​

Multiple Choice

Marine biologists have determined that _________ of all commercially and recreationally important species are found in our estuaries at some stage of their life cycle

• 80-85%

• 85-90%

• 90-95%

• 95-100%