Fisheries

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Fisheries
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http//www.pbs.org/emptyoceans/
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Traditional food production and distribution
practices are unable to feed the worlds 6.3
billion people
Will resources in the sea be able to provide
enough food to alleviate future problems of
malnutrition and starvation ?

• Most valuable living marine resources
• Fish
• Crustaceans
• Mollusks

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Location of the worlds major commercial fisheries
coastal areas
upwelling
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• Commercial fishing
• 500 species regularly caught
• employs 15 million people worldwide
• In 1999
• 137 million tons taken
• 70 billion

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World Harvest of Marine Fish (in millions of
metric tons)
Country 1995 1999 2000 _______________________
___________________ China 11 15 14.8 Peru 8
.9 8.4 10.6 Japan 5.9 5.1 4.9 United
States 5.2 4.7 4.7 Chile 7.4 5.0 4.3
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World Commercial Catch of Marine Fishes,
Crustaceans, and Mollusks (1995)
cod
Species Group Millions of Metric Tons, Live
Wt. Herrings, sardines, anchovies 22.0 Jacks,
mullets, sauries 11.2 Mollusks 11.0 Cods,
hake, haddock 10.6 Redfish, basses, conger
eels 7.0 Crustaceans 4.8 Tunas, bonitos,
billfish 4.7 Mackerel, snooks, cutlass
fishes 4.7 Flounders, halibut, soles
0.9 Miscellaneous marine fishes 17.7 Total
(excluding marine mammals) 94.6
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Food Non-Food Products
from the Sea
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• Non-Food Products from the Sea
• Bioactive Compounds
• Anti-viral (e.g., acyclovir)
• Anti-tumor (e.g., bryotstatin from a bryozoan,
  Didemnin-B from a tunicate)
• Insecticide (e.g., Padan from a marine annelid
  worm)
• B. Algin Agar products from seaweed
• Algin used to stiffen fabrics, as an emulsifier
  in salad dressings and paints, in ice cream to
  prevent formation of large ice crystals
• Agar and derivatives used extensively in
  microbiology and molecular biology as a gelling
  agent
• C. Whales Oil for lubrication, in cosmetics,
  bones for fertilizer
• D. Seals and sea lions furs

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• II. Food from the Sea
• Seaweeds
• Invertebrates (e.g., oysters, clams, crabs,
  lobster, squid, etc.)
• Fish (herring, mackerel, haddock, cod, tuna,
  mahi-mahi, etc.)
• Whales
• 1. Commercial whaling moratorium pronounced by
  the International Whaling Commission effective
  1987
• 2. Japan continued whaling Minke under provision
  for scientific research, but meat and blubber was
  sold at market
• 3. Beginning in 1993, Norway resumed whaling
  Minke 4. In 2000, Japan expanded to Blue and
  Brydes whales

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Fisheries Mismanagement
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Fisheries mismanagement

• Overfishing
• Commercial extinction
• Bycatch (27 million metric tons annually)
• Targeting smaller species on the low end of the
  food chain

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Peru Anchovy Fishery
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Peru Anchovy Fishery

• Upwelling zone off Peru
• Fishery began 1950
• Greatest fish catches for any single species
• Fish exported for domestic animal feed
• Fishery collapsed due to El Niño and overfishing

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Peru Anchovy Fishery
El Niño 1957 1965 1972 1976 1982-83
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Peru Anchovy Fishery
Normal Year
El Niño Year
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• Collapse of New England Fisheries
• Cod, haddock, ocean perch, herring, mackerel,
  blue fin tuna
• Georges Bank- highly productive, nutrient rich
  environment
• Prior to 1976, Russia, Japan, Norway, West
  Germany fished in Georges Bank

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Collapse of New England Fisheries Magnuson Act
passed prevented foreigners from fishing in
U.S. waters Fishery technology intensified and
resulted in overfishing Harvests were beyond the
max. sustainable yield Georges Bank closes after
collapse Some fish stocks begin to rebound
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Salmon

• Anadromous fish that migrate from sw to fw to
  spawn
• Spawning grounds affected by dam construction
• Aquaculture and restocking efforts

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Shark Overfishing

• Slow growth
• Low reproductive rate
• Late sexual maturity

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Orange Roughy

• Distribution world wide, high concentrations in
  New Zealand
• Found 700-1000m depth
• Life span slow-growing, long-lived, 150 years
• Size 30-40 cm
• Diet prawns, fish, squid
• Reproductive age 25-30 years old

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Fishing Techniques
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• Fishing Methods
• Harpoon - whales, swordfish, bluefin tuna
• Pole and line - mahi-mahi and used for tuna
  extensively in the 50s
• Longline - swordfish, tuna (pelagic) cod,
  halibut (bottom)
• Trolling - salmon, albacore, mahi-mahi
• Drift (gill) netting - various pelagic fish
• Trawl - anchovies (pelagic) cod, halibut
  (bottom)
• Purse seine - sardines, herring, mackerel
• Traps and Pots - Crabs, lobster, rock fish

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Drift Net
net size 20 m x 65 km
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Gill net
Purse seine
Bottom-dwelling fish
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Trawl haul
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Before trawl
After trawl
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Laws of the Sea Treaty
Allow nations to claim jurisdiction over their
territorial seas (contiguous sea beds and their
waters that extend off shore by 12 nautical miles)

• Exclusive Economic Zone (EEZ)
• 200 nautical miles
• under direct control of the country that owns the
  nearest land

• Regulates continental shelf resources
• Fishing
• Mineral exploration
• Scientific research

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Exclusive Economic Zone of the United States
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Fisheries Problems
Solutions
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• Fisheries Problems Solutions
• Maximum sustainable yield maximum amount of fish
  that can be harvested without depleting future
  stocks
• Worlds maximum sustainable yield estimated at
  100 to 135 million metric tons
• Present harvests are at about 100 million metric
  tons
• For fisheries where numbers available, estimated
  that 45 are currently over-fished
• A number of fisheries have already collapsed
  (Anchovy fishery off Peru, Cod fishery in the N.
  Atlantic)

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Fisheries Problems Solutions F. Bycatch (or
bykill) animals unintentionally killed during
harvest of the target species Trawling Bycatch
in shrimp trawling is very high (125 to 830 of
the catch is discarded as bycatch), turtles often
caught in trawls. SOLUTION trawls with trap
doors to let turtles escape
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Purse seine Tuna known to hang out under pods of
dolphins, nets set around pods of dolphins would
result in many drowning. SOLUTIONS Nets not
set around dolphin pods and/or employ backing
down, a technique that lowers upper edge of net
letting dolphins escape
Dolphins caught in tuna net
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• Fisheries Problems Solutions
• Bycatch
• Driftnets indiscriminate entangling of many
  sorts of marine animals
• SOLUTION banned in oceanic fisheries (but some
  countries still using them)
• Long lining Many albatross drown trying to
  snatch bait from long lines being deployed.
  snagged on hooks and pulled under.
• SOLUTION deploy in the dark or with special rig
  to let line out under water.

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Mariculture
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Mariculture or Aquaculture (marine
agriculture)- farming finfish, shellfish and
algae under favorable conditions
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One of every four fish eaten today was raised
in either a fw or sw fish farm.
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• Aquaculture also produces
• Bait fish
• Ornamental or aquarium fish
• Aquatic animals used to augment natural
  populations
• Algae for chemical extraction
• Pearl oysters

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• History
• 2000 years ago in Egypt, Rome, China
• 600 years ago France developed mussel aquaculture
• 500 years ago Europe developed the idea of using
  pond fertilizer to promote plankton growth
• 400 years ago China discovered that oysters would
  grow on bamboo stakes
• 1960s- Europe and U.S. catfish and salmon

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Criteria for selecting species for
farming - inexpensive to grow - grows
quickly - high sales price - resistant to
disease and parasites
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• Problems associated with Mariculture
• Wont make a dent in the shortfall in food supply
• Many farmed fish must be fed fish meal
• Produces much waste (especially shrimp)
• Destroys habitat for other species
• Crowded pens lead to disease (antibiotics)

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Hawaiian Fish Ponds
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TheAhupuaa
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Fishing Shrineskoa
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Hawaiian Fish Pondsloko ia
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• Molokai South Coast
• The ponds walls were made from lava boulders and
  coral.
• Walls keep the fish inside while allowing the sea
  water to ebb in and out.

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• Types of fish raised in ponds
• ulua (trevally)
• kumu (goatfish)
• kahala (amberjack)
• manini (convict tang)
• palani (surgeon)
• oio (bonefish)
• uhu (parrotfish)
• These fish were kept in a separate pond to breed
  and raised so they could easily be harvested by
  hand.

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Artificial Reefs

• Improve the local marine bio-density
• attract schools of fish
• providing habitats for the colonization of
  commercially valuable species
• improve the local inshore marine harvest

May wash up on beaches
construction rubble
tires
ship wrecks