Marine Fisheries Management

1
Marine Fisheries Management

• Original Power Point Created by Linda Rist
• Modified by Georgia Agricultural Education
  Curriculum Office
• June 2002

2
Ocean

• can be considered the last frontier on this
  planet
• unique physical characteristics

3
Ocean

• can support wide variety of plant and animal life

4
Physical Characteristics

• four major areas
• zonation
• salinity
• temperature density
• water movements

5
Zonation

• classify ocean zones
• depth measurements
• temperature changes
• pressure variations
• light penetration

6
Zonation

• depth and light penetration are the two most
  common methods
• five zones

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Zonation

• supratidal
• intertidal
• neritic
• bathyal
• abyssal

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Zonation

• supratidal and intertidal
• above the water level
• are omitted in some classifications

9
Intertidal

• sometimes called the littoral zone
• area between high and low tide

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Neritic

• begins at the water line
• contains more biological substance than any other
  part of the ocean
• 10-200 miles wide

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Neritic

• 200-600 feet deep
• zone stops at the end of the continental shelf
• site of huge dumping of industrial and city wastes

12
Bathyal

• contains the continental slope and rise
• is regarded as a geologically active area
• underwater avalanches and slides common

13
Abyssal

• ocean deep zone
• reaching depths of 5,000 meters
• trenches may extend to more than 6,000 meters

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Abyssal

• trenches are referred to as the hadal zone
• scarcity of food
• increased water pressure
• lack of dissolved oxygen

15
Abyssal

• animal life must be specialized to live
• must be able to obtain nutrients from rich
  sediments on the ocean floor

16
light penetration

• euphotic zone - twilight zone
• part of the ocean where sunlight penetrates the
  water
• supports plant and animal life that requires
  sunlight to live

17
Euphotic zone

• from the surface to about 600 feet beyond the
  horizontal shelf
• below the euphotic is the cold, dark Abyssal zone

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Salinity

• concentration of salts within ocean water
• concentrations and types of salts vary throughout
  the ocean

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Salinity

• most commonly found salt compounds consist of
• sodium - Na
• chlorine - Cl
• magnesium - Mg

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Salinity

• calcium - Ca
• potassium - K

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Salinity

• defined as the number of grams of dissolved salt
  in 1,000 grams of sea water
• symbol for expressing salinity is o

22
Salinity

• ranges in the ocean from 33o to 38o
• average is about 35o

23
Temperature Density

• the ocean is a giant heat pump that moves and
  transports heat from the equator to the poles

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Temperature Density

• temp changes occur as you move both to a
  different latitude and different depths

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Temp stratification

• three layers
• mixed surface layer
• middle thermocline layer (10-1,000 meters)
• deep water layer (1,000 - 6,000 meters)

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Thermocline

• below the light penetration depth
• suggests that there is a transfer of heat
  vertically as well as horizontally

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Density

• mass per unit volume
• dependent upon salinity
• temperature
• pressure

28
Density

• changes result from evaporation and heating of
  the oceans surface
• higher temps -lower density
• density increases as the pressure and depth
  increase

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Water Movements

• waves
• tides
• currents

30
Water Movements

• dictates temperature, salinity, nutrient levels
  as well as animal and plant life

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Waves

• classified as
• wind generated
• internal
• catastrophic
• stationary

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Wind generated

• most common
• sea
• swell
• surf

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Wind generated

• sea wave is an irregular wave with no systematic
  pattern
• sea wave travels at different heights and changes
  direction as it moves

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Wind generated

• swell waves are uniform with similar dimensions
• travel together because of their similar speed

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Wind generated-swell

• remain at a constant speed as they travel but
  decrease in height
• sometimes travel across an entire ocean

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Wind generated

• surf wave is on occurring close to shore
• water particles move in an orbital motion
• toward the beach

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Wind generated - surf

• less depth
• energy is directed toward the shore

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underwater internal

• found with the temperature changes in the depths
  of the ocean
• travels more slowly but has a greater height

39
Catastrophic waves

• massive power behind them
• caused by storms, hurricanes and landslides on
  shore
• commonly known catastrophic wave is the tidal wave

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Stationary wave

• occur in bays and calmer waters
• does not move horizontally
• water surface moves up and down

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Tides

• specialized waves caused by the gravitational
  attraction of the sun and moon on the earth
• tides occur at very exact times with one-half
  lunar day

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Tides

• 12 hours 25 minutes between high tides
• lunar day is longer than the solar day
• tides occur 50 minutes later each day

43
Tides

• an area will have either one high tide and one
  low tide each day (diurnal)
• or two high tides an two low tides each day
  (semidiurnal)

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Tides

• when the sun and the moon line up with the earth
  a strong tide is produced
• this happens every 14 days at the time of the new
  and full moons

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Tides

• this exceptionally high tide is called the spring
  tide
• when the sun and moon are at right angles with
  each other
• occurs during the half moon

46
Tides

• an exceptionally low tide is produced
• called neap tide

47
Currents

• most common are surface currents, turbidity
  currents and bottom currents
• surface currents, which are caused by the
  prevailing winds

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Currents - surface

• reach velocities of about 3 knots
• 1 knot 1.15 mph

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Currents

• when a hurricane reaches shore or an earthquake
  occurs, landslides can occur
• landslides can produce a turbidity current
  underwater

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Currents

• in the deep water become the bottom currents
• responsible for moving sediments on the ocean
  floor

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Currents

• transporting water from the Atlantic Basin to the
  southern Atlantic Ocean

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Life

• the ocean is a wonderland of plant and animal
  life
• storehouse of food and nutrients is virtually
  untapped

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Life

• with proper management the ocean could provide
  wide relief to the world food problem

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Animal life

• divided into four major groups
• microscopic
• marine fish
• marine shellfish
• marine mammals

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Microscopic

• most common are the plankton
• zooplankton
• staple food for species ranging from tiny fish to
  whales

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Microscopic

• many zooplankton are related to marine crabs and
  shrimp
• plankton concentration varies
• average concentration is one tenth of a gram per
  cubic meter of water

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Microscopic

• some scientists suggest harvesting plankton
  because they contain the nutrients and amino
  acids found in human food

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Microscopic

• would require filtering over one million gallons
  of water with sophisticated nets to collect one
  pound of dry plankton material

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Marine Fish

• four most important marine fish species are
• salmon
• tuna
• menhaden
• flounder

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Marine Fish

• these species make up the world fishing markets
• less economically important species include
• haddock, herring, cod, and mackerel

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Salmon

• seven main species
• Atlantic
• Cherry
• Chinook
• Chum

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Salmon

• Coho
• Pink
• Sockeye

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Salmon

• range in size from 16 inches long and weighing 5
  pounds to 36 inches and 25 pounds
• live in both the Atlantic and Pacific Oceans

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Salmon

• begin life in fresh water
• migrate to the ocean to live and grow
• Atlantic Salmon make the trip repeatedly

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Salmon

• Pacific species
• include all or the seven except the Atlantic
• spawn only once and die soon afterward

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Salmon

• spawn in shallow streams during late summer or
  early fall
• female finds a rocky stream bed where she digs a
  saucer shaped nest with her tail

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Salmon

• male salmon stays close by to guard the female
• she deposits her eggs in the nest and the male
  fertilizes them

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Salmon

• procedure is repeated upstream
• female will lay 2,000 - 10,000 eggs during this
  spawning time

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Salmon

• eggs hatch in 3-4 months
• fry retreat to the gravel bottom to try to avoid
  predators - birds and other fish

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Salmon

• young salmon live off food in the yolk sack
  attached to their stomachs
• some species move toward the ocean immediately

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Salmon

• some stay in fresh water for up to 3 years
• adult salmon remain in the ocean from 6 months to
  5 years before returning to fresh water to spawn

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Salmon

• Once the salmon reaches fresh water it stops
  eating and depends on body fat for energy
• male develops a hooked snout

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Salmon

• some species develop a hump on their backs
• quality of the meat is decreased at this time as
  the salmon loses some of its flavor

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Salmon

• management practices to protect and preserve
• fish ladders to help salmon over dams
• artificial spawning channels

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Salmon

• temp and water flow are controlled in the
  channels
• use of hatcheries
• construction of escarpments which allow a certain
  number of fish to spawn

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Salmon

• have also been used to control other rapidly
  producing fish species
• coho salmon was introduced into the great lakes
  to control alewives

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Salmon

• commercially are caught in nets and sold
• fresh
• frozen
• smoked and canned

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Salmon

• main fishing countries are
• US
• Japan
• Canada

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Tuna

• member of the mackerel family
• leading game fish in the US

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Tuna

• three most commercially important types are
• albacore
• skipjack
• yellowfin

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Tuna

• species range in size from the 10 foot long,
  2,000 pound northern bluefin to the 2 foot long
  10 pound frigate

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Tuna

• are fast swimmers
• reach speeds of up to 45 mph
• Does not have the ability to push water through
  its gills

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Tuna

• must swim continuously in order to live
• caught by bait fishing, long lining and purse
  seining
• bait fishing involves using live bait to attract
  tuna

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Tuna

• long-lining
• reel out a line up to 75 miles long
• may have as many as 2,000 hooks

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Tuna

• purse seining
• using nets called purse seines to catch fish
• tuna usually travel below schools of porpoises

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Tuna

• pilots locate the porpoises from the air and
  radio the location to the boats
• major problem is that many porpoises are netted
  at the same time

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Tuna

• netting of porpoises is accidental and unlawful

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Menhaden

• also known as bony fish or fatbacks
• live in the Atlantic Ocean and feed on plankton
• swim in schools close to the oceans surface

89
Menhaden

• easy to catch
• 12-18 inches long
• weigh about 1 pound at maturity

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Menhaden

• most are used in products such as livestock feed,
  soap, and fertilizer, rather than human food

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Flounder

• also called Plaice
• lives on the sandy and muddy bottoms of bays
• have a flat body with both eyes on the same side
  of the head

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Flounder

• feed on shrimp and small fish

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Marine shellfish

• shrimp
• oysters
• crab
• lobster

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Shrimp

• most economically important of the marine
  shellfish
• live in salt and fresh water
• excellent swimmers

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Shrimp

• large shrimp - called prawns
• feed from the ocean floor
• can grow to 12 inches in length

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Shrimp

• most common used for food is the Peneid shrimp
• hatched from eggs laid in the ocean
• female may lay 500,000 to 1 million eggs

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Shrimp

• as the young shrimp move toward shore
• 80 percent are lost to predators
• shrimp settle in bays and river mouths until 5-7
  mos

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Shrimp

• then move back to deeper water for breeding
• female dies soon after laying her eggs

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Shrimp

• nets called trawls are dragged on the ocean floor
• once netted, shrimp are sold frozen or canned
• leading countries are US, Japan, India

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Oyster

• type of mollusk
• shellfish with a two-piece shell protecting a
  soft inner body
• live in mild or warm climates

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Oyster

• Oysters of the Persian gulf and the Pacific Ocean
  are responsible for making pearls

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Oyster

• female oyster lays about 500 million eggs each
  year, spraying them into the water
• young oysters, called spat, hatches 10 hours later

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Oyster

• about the size of the point of a needle
• within 24 hours the shell starts to form
• young oyster attaches to a rock

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Oyster

• where it spends the rest of its life
• some live up to 20 years
• greatest enemies include humans, fish, crabs,
  starfish and oyster drills

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Crabs

• third economically important marine shellfish
• habitats range from shallow waters close to shore
  to deep waters of the ocean

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Crabs

• 4500 different kinds of crabs
• most common - Atlantic - lives in burrows on
  saltwater streams

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Crabs

• largest is the Alaskan King Crab
• can weigh up to 12 pounds!
• Most sought after crab by American and Japanese
  fishermen

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Lobster

• American Lobster lives on ocean bottoms near the
  shore in both the Atlantic and Pacific Oceans
• averages 12-24 inches in length

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Lobster

• weigh from 1 - 20 pounds
• feeds by burrowing into a hole with only its claw
  at the edge

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Lobster

• as prey comes close to the claw it quickly
  becomes the lobsters next meal
• main food consists of crab, snails, small fish
  and other lobsters

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Lobsters

• female carries her eggs under her tail for 11-12
  months
• every 2 years she lays 5,000 - 100,000 eggs by
  shaking the eggs from eggshells

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Lobsters

• eggs will quickly rise to the surface
• young will drift on the surface for three to five
  weeks
• easy prey for birds and fish

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Lobsters

• young then sink to the ocean floor where they
  spend the remainder of their life
• life span up to 15 years

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Lobsters

• caught in traps called pots
• allow the lobster to enter but vertical wooden
  bars confuse the lobsters and prevent them from
  finding their way out

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Lobsters

• traps are checked daily
• two lobsters in confinement will fight till one
  dies
• claws are immobilized with a rubber band to
  prevent injury to other lobsters

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Lobsters

• Lobsters are kept together for shipping so
  immobilizing the claw is important

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Marine Mammals

• differ from other marine life in two important
  ways
• warm blooded rather than cold blooded

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Marine Mammals

• mammals have lungs as breathing devices rather
  than gills
• necessary to come to the surface to breath

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Marine Mammals

• main marine mammals are
• whales
• porpoises
• walruses
• fur seals

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Whales

• include the largest mammals that have ever lived
  on the earth
• the largest blue whale was 100 feet long and
  weight 136 metric tons

121
Whales

• divided into baleen whales and toothed whales

122
Baleen Whales

• obtain their food by straining plankton from the
  seawater
• through plates called whalebone

123
Baleen Whales

• ten different types
• three major groups
• right, gray, and rorqual

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Baleen Whales

• Right include the bowhead
• black right - longest baleen, averages 60 feet
  long
• pygmy baleen- smallest baleen

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Baleen

• gray are black to gray in color and dotted with
  white blotches
• feed from the ocean floor

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Rorqual baleen

• fastest whale
• able to flee the whalers harpoon until the
  introduction of the diesel engine

127
Rorquals

• sometimes referred to as finback
• fin protrudes from their back

128
Rorquals

• most common include
• blue
• brydes
• fin
• humpback

129
Rorquals

• minke
• sei
• common food is small shrimp like animal called
  krill

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Toothed whales

• have a lower set of peglike teeth
• over 65 different kinds of toothed whales

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Toothed whales

• five major groups
• sperm
• beaked
• belugas and narwhales

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Toothed Whales

• dolphins and porpoises
• river dolphins

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Sperm Whale

• largest toothed whale
• about 60 feet in length
• blue gray to black in color
• enormous square head

134
Sperm whales

• live in the tropical waters
• feed off of squid, barracuda and sharks

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Whales

• usually seasonal breeders
• mating during the winter months
• male - bull
• female - cow

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Whales

• migrate to the equator for mating
• most baleen whales migrate
• most toothed whales do not migrate

137
Whales

• pregnancy lasts 10-12 months
• when the calf is born it weighs nearly 4000
  pounds
• 23 feet long

138
Whales

• cow nurses her offspring for about 7 months
• because of the rich milk, some calves can gain as
  much as 200 pounds a day

139
Whales

• travel in herds of 100 - 1,000
• adult male will form a harem school consisting of
  himself, his females and their young

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Whales

• nursery groups of females and young and bachelor
  groups of males also travel along with the harem

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Migrating

• mothers and young lead the herd
• followed by males and non pregnant females
• pregnant females at the rear

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Whales

• average life span is 15 years for a porpoise and
  40 years for a baleen whale

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Fur Seals

• seals are divided into three groups
• eared - includes fur seals and sea lions
• earless
• walruses

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Fur Seals

• most sought after seal because eof its soft coat
• US annual catch of fur seals amounts to over 3.5
  million

145
Fur Seals

• spend the winter off the coast of California and
  the summer in Alaska
• male seal is called a bull and weighs between 500
  and 700 pounds

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Fur Seals

• female is called a cow
• weighs 50-100 pounds
• bears one offspring per year
• offspring are called a pup, whelp, or calf

147
Fur Seals

• bulls arrive at the breeding grounds called
  rookeries in May or June
• stake out their territories
• about 40 feet in diameter

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Fur Seals

• cows arrive in July
• immediately join a harem and bear their young
• cow mates again 1 - 2 weeks after the birth of
  the pup

149
Fur Seals

• bull is always being challenged by other bulls
  for his territory
• usually must be at least 10 years old before he
  develops enough strength to defend

150
Fur Seals

• main predators include sharks
• killer whales
• and parasitic round worms
• humans

151
Fur Seals

• thousands killed annually at their breeding
  ground for fur
• 1911 North Pacific Fur Convention
• Japan, Russia, Canada, and the US

152
Fur Seals

• set a limit to the number of seals that can be
  harvested each year
• Only Russia and the US can harvest 30,000 a year

153
Fur Seals

• each country gives 15 of harvest to Japan and
  15 to Canada
• US sealing is conducted by the government

154
Fur Seals

• money is deposited in the US Treasury
• 70 of money is returned to Alaskan govt.
• 30 goes to the National Marine Fisheries Service

155
Walrus

• the only tusked seals
• live in the Arctic, North Atlantic, and North
  Pacific Regions

156
Walrus

• their bodies have developed flippers that make
  them excellent swimmers
• during winter and spring months, walruses drift
  on floating ice pieces

157
Walrus

• spend summers resting on shorelines
• main food is clams
• Eskimo is the most common user of Walruses

158
Walrus

• meat is used for food
• hides for shelter
• oil for lamps

159
Estuarine Ecosystem

• area where freshwater source opens into the ocean
• called an estuary

160
Estuary

• transition area supports a variety of life that
  is found nowhere else
• life that can withstand rapid changes in
  salinity, temperature and density

161
Estuary

• continuously receives fresh water from the rivers
  and streams and salt water from the tides and
  currents

162
Estuary

• transitional zone
• has characteristics common to neither rivers or
  the ocean

163
Estuary

• usually shallow and turbulent
• results in high amount of oxygen in the water

164
Estuary

• tides cause the area to be nutrient rich
• rivers bring nutrients to the estuary from above
  and the tides bring nutrients from the ocean

165
Estuary

• acts as a nutrient trap
• bacteria count is high because of the high oxygen
  content

166
Estuary

• rapid decomposition of organic wastes
• breakdown of organic matter to soluble nutrients
  causes plant life to prosper

167
Estuary

• high plant life attracts large numbers of plant
  eating fish
• life in the estuary is grouped into three groups
• 1. Species that travel a short distance to the
  estuary

168
Estuary

• 2. Species found in both the estuary and in
  other parts of the ocean
• 3. Species whose entire life cycles are in the
  estuary

169
Estuary

• economically important to marine fisheries
• 90 of the marine fish harvested either comes
  from the estuarine ecosystem or passes through it

170
Estuary

• best known life in the estuary include fish
  larvae
• oysters
• clams, crabs
• lobsters, shrimp

171
Estuary

• problems facing estuaries include conflict
  between land developers and fishermen

172
Estuary

• shorelines are the most sought after types of
  real estate
• some estuaries have been used as a dumping ground

173
Estuary

• dumping destroys natural habitat

174
Artificial Ocean Cultivation

• scientists have developed ways to artificially
  propagate marine animals
• this form of agricultural production is called
  aquaculture

175
Artificial Ocean Cultivation

• most commonly farmed marine resource crop is the
  oyster
• research is also being conducted with shrimp,
  salmon and milkfish

176
Oysters

• live in estuarine waters
• close to shore
• makes them one of the easiest marine animals to
  raise

177
Oysters

• improving habitat is first step
• providing a place for larvae to attach
• control parasites and predators

178
Oysters

• French Scientists have developed a special algae
  as an improved food for the oysters to grow more
  quickly.

179
Oysters

• Japans most productive oyster farm
• Inland Sea near Hiroshima
• water flow and mineral content are correct

180
Oysters

• very desirable oyster producing area
• only management item needed is a stopping
  apparatus to which the larvae can attach

181
Oysters

• Japanese oyster farms consist of bamboo poles
  tied together and floating on barrels
• wires are hung from the poles to a depth of 20
  feet

182
Oysters

• wires hold clam shells
• act as the stopping place for oyster larvae
• In July and August, billions of oyster larvae
  attach to the artificially hung shells

183
Oysters

• larvae are thinned to the correct amount
• midseason - October - wires are pulled and young
  oysters are cleaned and brushed which helps them
  grow

184
Oysters

• harvested in January and February
• standard oyster raft measures 35-40 feet square
• may own as many as 100 rafts

185
Oysters

• number of barrels needed to support the raft
  increases as the oysters grow and weigh it down

186
Oysters

• feed on plankton
• costs are low
• average yield is about 13,000 pounds of oyster
  flesh per acre farmed

187
Oysters

• shells are cleaned and sold for poultry grit and
  lime
• Japan can attribute its successful oyster farming
  both to low labor costs and to preservation of
  habitat

188
Oysters

• pollution of waters has almost stripped every
  other nation of an economically feasible oyster
  industry

189
Laws and Regulations

• who owns the ocean
• how many miles offshore can a country claim
• who owns the mineral resources on the ocean floor

190
Laws and Regs

• development of fishing policy
• fish cannot be claimed as property like land
  wildlife can

191
Laws and Regs

• recent legislation is aimed at conservation
• variety of commissions and committees have been
  formed

192
Laws and Regs

• most deal with regulation of one specific
  resource ie fur seals, whale, tuna
• major examples include
• Inter-American Tropical Tuna Commission (IATTC)

193
Laws and Regs

• International Commission for Northwest Atlantic
  Fisheries (ICNAF)
• International North Pacific Fisheries Commission
  (INPFC

194
Laws and Regs

• International Whaling Commission (IWC)
• most commissions are formed after a resource
  develops problems

195
Laws and Regs

• commissions are only as strong as their member
  nations want them to be
• most recent attempt to develop ocean regulations
  is the UNs Law of the Sea

196
Laws and Regs

• a set of bargaining conferences
• involve 150 nations
• first conference initiated in 1958

197
Laws and Regs

• other conferences held in 1960, 73, and 80
• three major items discussed
• 1. Territorial limits

198
Laws and Regs

• 2. Jurisdiction over an exclusive economic zone
• 3. Seabed mining

199
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