Marine Fisheries Management

Ocean• can be considered the last

frontier on this planet

• unique physical characteristics

Ocean• can support wide variety of

plant and animal life

Physical Characteristics

• four major areas

• zonation

• salinity

• temperature density

• water movements

Zonation• classify ocean zones

• depth measurements

• temperature changes

• pressure variations

• light penetration

Zonation• depth and light penetration

are the two most common methods

• five zones

Zonation• supratidal

• intertidal

• neritic

• bathyal

• abyssal

Zonation• supratidal and intertidal

• above the water level

• are omitted in some classifications

Intertidal• sometimes called the littoral

zone

• area between high and low tide

Neritic• begins at the water line

• contains more biological substance than any other part of the ocean

• 10-200 miles wide

Neritic• 200-600 feet deep

• zone stops at the end of the continental shelf

• site of huge dumping of industrial and city wastes

Bathyal• contains the continental slope

and rise

• is regarded as a geologically active area

• underwater avalanches and slides common

Abyssal• ocean deep zone

• reaching depths of 5,000 meters

• trenches may extend to more than 6,000 meters

Abyssal• trenches are referred to as the

hadal zone

• scarcity of food

• increased water pressure

• lack of dissolved oxygen

Abyssal• animal life must be

specialized to live

• must be able to obtain nutrients from rich sediments on the ocean floor

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

Euphotic zone• from the surface to about 600

feet beyond the horizontal shelf

• below the euphotic is the cold, dark Abyssal zone

Salinity• concentration of salts within

ocean water

• concentrations and types of salts vary throughout the ocean

Salinity• most commonly found salt

compounds consist of:

• sodium - Na

• chlorine - Cl

• magnesium - Mg

Salinity• calcium - Ca

• potassium - K

Salinity• defined as the number of

grams of dissolved salt in 1,000 grams of sea water

• symbol for expressing salinity is %o

Salinity• ranges in the ocean from

33%o to 38%o

• average is about 35%o

Temperature Density• the ocean is a giant heat

pump that moves and transports heat from the equator to the poles

Temperature Density• temp changes occur as you

move both to a different latitude and different depths

Temp stratification• three layers• mixed surface layer• middle thermocline layer (10-

1,000 meters)• deep water layer (1,000 - 6,000

meters)

Thermocline• below the light penetration

depth

• suggests that there is a transfer of heat vertically as well as horizontally

Density• mass per unit volume

• dependent upon salinity

• temperature

• pressure

Density• changes result from evaporation

and heating of the ocean’s surface

• higher temps -lower density

• density increases as the pressure and depth increase

Water Movements• waves

• tides

• currents

Water Movements• dictates temperature, salinity,

nutrient levels as well as animal and plant life

Waves• classified as:

• wind generated

• internal

• catastrophic

• stationary

Wind generated• most common

• sea

• swell

• surf

Wind generated• sea wave is an irregular wave

with no systematic pattern

• sea wave travels at different heights and changes direction as it moves

Wind generated• swell waves are uniform with

similar dimensions

• travel together because of their similar speed

Wind generated-swell• remain at a constant speed as

they travel but decrease in height

• sometimes travel across an entire ocean

Wind generated• surf wave is on occurring

close to shore

• water particles move in an orbital motion

• toward the beach

Wind generated - surf• less depth

• energy is directed toward the shore

underwater internal• found with the temperature

changes in the depths of the ocean

• travels more slowly but has a greater height

Catastrophic waves• massive power behind them

• caused by storms, hurricanes and landslides on shore

• commonly known catastrophic wave is the tidal wave

Stationary wave• occur in bays and calmer

waters

• does not move horizontally

• water surface moves up and down

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

Tides• 12 hours 25 minutes between

high tides

• lunar day is longer than the solar day

• tides occur 50 minutes later each day

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)

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

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

Tides• an exceptionally low tide is

produced

• called neap tide

Currents• most common are surface

currents, turbidity currents and bottom currents

• surface currents, which are caused by the prevailing winds

Currents - surface• reach velocities of about 3

knots

• 1 knot = 1.15 mph

Currents• when a hurricane reaches

shore or an earthquake occurs, landslides can occur

• landslides can produce a turbidity current underwater

Currents• in the deep water become the

bottom currents

• responsible for moving sediments on the ocean floor

Currents• transporting water from the

Atlantic Basin to the southern Atlantic Ocean

Life• the ocean is a wonderland of

plant and animal life

• storehouse of food and nutrients is virtually untapped

Life• with proper management the

ocean could provide wide relief to the world food problem

Animal life• divided into four major groups

• microscopic

• marine fish

• marine shellfish

• marine mammals

Microscopic• most common are the plankton

• zooplankton

• staple food for species ranging from tiny fish to whales

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

Microscopic• some scientists suggest

harvesting plankton because they contain the nutrients and amino acids found in human food

Microscopic• would require filtering over

one million gallons of water with sophisticated nets to collect one pound of dry plankton material

Marine Fish• four most important marine fish

species are:• salmon• tuna• menhaden• flounder

Marine Fish• these species make up the world

fishing markets

• less economically important species include:

• haddock, herring, cod, and mackerel

Salmon• seven main species

• Atlantic

• Cherry

• Chinook

• Chum

Salmon• Coho

• Pink

• Sockeye

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

Salmon• begin life in fresh water

• migrate to the ocean to live and grow

• Atlantic Salmon make the trip repeatedly

Salmon• Pacific species

• include all or the seven except the Atlantic

• spawn only once and die soon afterward

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

Salmon• male salmon stays close by

to guard the female

• she deposits her eggs in the nest and the male fertilizes them

Salmon• procedure is repeated

upstream

• female will lay 2,000 - 10,000 eggs during this spawning time

Salmon• eggs hatch in 3-4 months

• fry retreat to the gravel bottom to try to avoid predators - birds and other fish

Salmon• young salmon live off food

in the yolk sack attached to their stomachs

• some species move toward the ocean immediately

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

Salmon• Once the salmon reaches fresh

water it stops eating and depends on body fat for energy

• male develops a hooked snout

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

Salmon• management practices to

protect and preserve

• fish ladders to help salmon over dams

• artificial spawning channels

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

Salmon• have also been used to control

other rapidly producing fish species

• coho salmon was introduced into the great lakes to control alewives

Salmon• commercially are caught in

nets and sold

• fresh

• frozen

• smoked and canned

Salmon• main fishing countries are:

• US

• Japan

• Canada

Tuna• member of the mackerel

family

• leading game fish in the US

Tuna• three most commercially

important types are:

• albacore

• skipjack

• yellowfin

Tuna• species range in size from the

10 foot long, 2,000 pound northern bluefin to the 2 foot long 10 pound frigate

Tuna• are fast swimmers

• reach speeds of up to 45 mph

• Does not have the ability to push water through its gills

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

Tuna• long-lining

• reel out a line up to 75 miles long

• may have as many as 2,000 hooks

Tuna• purse seining

• using nets called purse seines to catch fish

• tuna usually travel below schools of porpoises

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

Tuna• netting of porpoises is

accidental and unlawful

Menhaden• also known as bony fish or

fatbacks

• live in the Atlantic Ocean and feed on plankton

• swim in schools close to the ocean’s surface

Menhaden• easy to catch

• 12-18 inches long

• weigh about 1 pound at maturity

Menhaden• most are used in products

such as livestock feed, soap, and fertilizer, rather than human food

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

Flounder• feed on shrimp and small fish

Marine shellfish• shrimp

• oysters

• crab

• lobster

Shrimp• most economically important

of the marine shellfish

• live in salt and fresh water

• excellent swimmers

Shrimp• large shrimp - called prawns

• feed from the ocean floor

• can grow to 12 inches in length

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

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

Shrimp• then move back to deeper

water for breeding

• female dies soon after laying her eggs

Shrimp• nets called trawls are dragged on

the ocean floor

• once netted, shrimp are sold frozen or canned

• leading countries are US, Japan, India

Oyster• type of mollusk

• shellfish with a two-piece shell protecting a soft inner body

• live in mild or warm climates

Oyster• Oysters of the Persian gulf

and the Pacific Ocean are responsible for making pearls

Oyster• female oyster lays about 500

million eggs each year, spraying them into the water

• young oysters, called spat, hatches 10 hours later

Oyster• about the size of the point of a

needle

• within 24 hours the shell starts to form

• young oyster attaches to a rock

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

Crabs• third economically important

marine shellfish

• habitats range from shallow waters close to shore to deep waters of the ocean

Crabs• 4500 different kinds of crabs

• most common - Atlantic - lives in burrows on saltwater streams

Crabs• largest is the Alaskan King Crab

• can weigh up to 12 pounds!

• Most sought after crab by American and Japanese fishermen

Lobster• American Lobster lives on

ocean bottoms near the shore in both the Atlantic and Pacific Oceans

• averages 12-24 inches in length

Lobster• weigh from 1 - 20 pounds

• feeds by burrowing into a hole with only its claw at the edge

Lobster• as prey comes close to the claw

it quickly becomes the lobster’s next meal

• main food consists of crab, snails, small fish and other lobsters

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

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

Lobsters• young then sink to the ocean

floor where they spend the remainder of their life

• life span up to 15 years

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

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

Lobsters• Lobsters are kept together for

shipping so immobilizing the claw is important

Marine Mammals• differ from other marine life

in two important ways

• warm blooded rather than cold blooded

Marine Mammals• mammals have lungs as

breathing devices rather than gills

• necessary to come to the surface to breath

Marine Mammals• main marine mammals are

• whales

• porpoises

• walruses

• fur seals

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

Whales• divided into baleen whales

and toothed whales

Baleen Whales• obtain their food by straining

plankton from the seawater

• through plates called whalebone

Baleen Whales• ten different types

• three major groups

• right, gray, and rorqual

Baleen Whales• Right include the bowhead

• black right - longest baleen, averages 60 feet long

• pygmy baleen- smallest baleen

Baleen• gray are black to gray in

color and dotted with white blotches

• feed from the ocean floor

Rorqual baleen• fastest whale

• able to flee the whaler’s harpoon until the introduction of the diesel engine

Rorquals• sometimes referred to as

finback

• fin protrudes from their back

Rorquals• most common include

• blue

• bryde’s

• fin

• humpback

Rorquals• minke

• sei

• common food is small shrimp like animal called krill

Toothed whales• have a lower set of peglike

teeth

• over 65 different kinds of toothed whales

Toothed whales• five major groups

• sperm

• beaked

• belugas and narwhales

Toothed Whales• dolphins and porpoises

• river dolphins

Sperm Whale• largest toothed whale

• about 60 feet in length

• blue gray to black in color

• enormous square head

Sperm whales• live in the tropical waters

• feed off of squid, barracuda and sharks

Whales• usually seasonal breeders

• mating during the winter months

• male - bull

• female - cow

Whales• migrate to the equator for

mating

• most baleen whales migrate

• most toothed whales do not migrate

Whales• pregnancy lasts 10-12

months

• when the calf is born it weighs nearly 4000 pounds

• 23 feet long

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

Whales• travel in herds of 100 - 1,000

• adult male will form a harem school consisting of himself, his females and their young

Whales• nursery groups of females

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

Migrating• mothers and young lead the

herd

• followed by males and non pregnant females

• pregnant females at the rear

Whales• average life span is 15 years

for a porpoise and 40 years for a baleen whale

Fur Seals• seals are divided into three groups

• eared - includes fur seals and sea lions

• earless

• walruses

Fur Seals• most sought after seal

because eof its soft coat

• US annual catch of fur seals amounts to over $3.5 million

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

Fur Seals• female is called a cow

• weighs 50-100 pounds

• bears one offspring per year

• offspring are called a pup, whelp, or calf

Fur Seals• bulls arrive at the breeding

grounds called rookeries in May or June

• stake out their territories

• about 40 feet in diameter

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

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

Fur Seals• main predators include

sharks

• killer whales

• and parasitic round worms

• humans

Fur Seals• thousands killed annually at their

breeding ground for fur

• 1911 North Pacific Fur Convention

• Japan, Russia, Canada, and the US

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

Fur Seals• each country gives 15% of

harvest to Japan and 15% to Canada

• US sealing is conducted by the government

Fur Seals• money is deposited in the US

Treasury

• 70% of money is returned to Alaskan gov’t.

• 30% goes to the National Marine Fisheries Service

Walrus• the only tusked seals

• live in the Arctic, North Atlantic, and North Pacific Regions

Walrus• their bodies have developed

flippers that make them excellent swimmers

• during winter and spring months, walruses drift on floating ice pieces

Walrus• spend summers resting on

shorelines

• main food is clams

• Eskimo is the most common user of Walruses

Walrus• meat is used for food

• hides for shelter

• oil for lamps

Estuarine Ecosystem• area where freshwater source

opens into the ocean

• called an estuary

Estuary• transition area supports a variety

of life that is found nowhere else

• life that can withstand rapid changes in salinity, temperature and density

Estuary• continuously receives fresh

water from the rivers and streams and salt water from the tides and currents

Estuary• transitional zone

• has characteristics common to neither rivers or the ocean

Estuary• usually shallow and turbulent

• results in high amount of oxygen in the water

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

Estuary• acts as a nutrient trap

• bacteria count is high because of the high oxygen content

Estuary• rapid decomposition of

organic wastes

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

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

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

Estuary• economically important to

marine fisheries

• 90% of the marine fish harvested either comes from the estuarine ecosystem or passes through it

Estuary• best known life in the estuary

include: fish larvae

• oysters

• clams, crabs

• lobsters, shrimp

Estuary• problems facing estuaries

include conflict between land developers and fishermen

Estuary• shorelines are the most

sought after types of real estate

• some estuaries have been used as a dumping ground

Estuary• dumping destroys natural

habitat

Artificial Ocean Cultivation

• scientists have developed ways to artificially propagate marine animals

• this form of agricultural production is called aquaculture

Artificial Ocean Cultivation

• most commonly farmed marine resource crop is the oyster

• research is also being conducted with shrimp, salmon and milkfish

Oysters• live in estuarine waters

• close to shore

• makes them one of the easiest marine animals to raise

Oysters• improving habitat is first step

• providing a place for larvae to attach

• control parasites and predators

Oysters• French Scientists have

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

Oysters• Japan’s most productive

oyster farm

• Inland Sea near Hiroshima

• water flow and mineral content are correct

Oysters• very desirable oyster producing

area

• only management item needed is a stopping apparatus to which the larvae can attach

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

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

Oysters• larvae are thinned to the correct

amount

• midseason - October - wires are pulled and young oysters are cleaned and brushed which helps them grow

Oysters• harvested in January and

February

• standard oyster raft measures 35-40 feet square

• may own as many as 100 rafts

Oysters• number of barrels needed to

support the raft increases as the oysters grow and weigh it down

Oysters• feed on plankton

• costs are low

• average yield is about 13,000 pounds of oyster flesh per acre farmed

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

Oysters• pollution of waters has

almost stripped every other nation of an economically feasible oyster industry

Laws and Regulations• who owns the ocean

• how many miles offshore can a country claim

• who owns the mineral resources on the ocean floor

Laws and Regs• development of fishing

policy

• fish cannot be claimed as property like land wildlife can

Laws and Regs• recent legislation is aimed at

conservation

• variety of commissions and committees have been formed

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)

Laws and Regs• International Commission for

Northwest Atlantic Fisheries (ICNAF)

• International North Pacific Fisheries Commission (INPFC

Laws and Regs• International Whaling

Commission (IWC)

• most commissions are formed after a resource develops problems

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 UN’s Law of the Sea

Laws and Regs• a set of bargaining

conferences

• involve 150 nations

• first conference initiated in 1958

Laws and Regs• other conferences held in

1960, 73, and 80

• three major items discussed

• 1. Territorial limits

Laws and Regs• 2. Jurisdiction over an

exclusive economic zone

• 3. Seabed mining