5.02 saltwater fish and environment

depth and light penetration

Zones can be classified by many methods, though most commonly by ___.

Supratidal

• above water level, above high tide and below vegetation line

Intertidal

• area between low tide and high tide

Neritic

• starts at waterline and goes to about 660 feet of depth, though the depth and width can vary; stops at the end of the continental shelf.

Bathyal

• also known as the midnight zone, contains continental slope

Abyssal

• very deep parts; never receives sunlight; considered the deep ocean zone, between 13,000 to 20,000 feet of depth

Water Movements

include tides and currents.

Tides

are specialized waves caused by the gravitational attraction of the sun and moon on the earth.
Occur at regular intervals with one half lunar day (12 hours and 25 minutes) between high tides
___ cause the estuarine areas to be nutrient rich.

50

Because lunar days are longer than solar days, tides occur ___ minutes later each day.

spring

When the sun and moon line up with the earth, a strong tide is produced and this is called a ___ tide.

neap

When the sun and moon are at right angles with each other, an exceptionally low tide is produced, called a ___ tide.

winds

Surface currents are caused by ___.

Turbidity currents

-caused by earthquakes or hurricanes.

Bottom currents

• in deep water; responsible for moving sediments on the ocean floor.

Estuary

• where a freshwater source opens into the ocean.
  Usually is shallow and turbulent, which results in high amounts of dissolved oxygen in the water.

oxygen

The bacteria count is high because of the high amount of ___ , which causes rapid decomposition of organic wastes.

90%

About ___ of marine fish harvest by American fishers either come from the estuarine ecosystem or passes through between spawning and maturity.

Salmon

7 main species (Atlantic, cherry, chinook, chum, coho, pink, and sockeye)
Live in both of Atlantic and Pacific Oceans

Anadromous Fish

begin life in freshwater, migrate to the ocean to live and grow and finally return to freshwater to spawn.

Tuna

Member of the mackerel family; the leading game fish in the United States
Fast swimmers reaching speeds of over 45 miles per hour
Cannot push water through gills, so must swim continuously to live

Menhaden

Also known as bony fish or fatbacks
98% is processed into fish meal, proteins, and oils; used for animal feeds, fertilizers, and cosmetics

Flounder

Also known as Plaice; lives on sandy and muddy bottoms
Migrates offshore to spawn and then returns to coastal estuaries
Known for flat body with both eyes on the same side of the head.

Shrimp

342 different species have commercial value as food or bait.
Can spawn a couple of times per year, producing between 150,000 and 1 million eggs per spawn

Oyster

A type of mollusk with a two piece shell protecting a soft inner body, found in warm shallow waters in colonies called 'beds'
Provide hard surface structure and hiding place for other organisms, stabilize shorelines, and minimize storm water erosion.
Can filter 50 gallons of seawater per day, reducing phytoplankton and increasing water clarity

Crabs

Typically have one pair of chelipeds or claws and four pairs of walking legs
Largest is the Alaskan king, which can weigh up to 12 lbs.

Lobster

Lives on the ocean bottom near the shore in both the Atlantic and Pacific oceans
Can live up to 60 years