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Fishing Practices

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Emptying the oceans We are placing unprecedented pressure on marine resources Half the world s marine fish populations are fully exploited 25% of fish population ... – PowerPoint PPT presentation

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Title: Fishing Practices


1
Fishing Practices
2
  • Commercial fishing
  • 500 species regularly caught
  • Employs 200 million people worldwide
  • In 2002 the world fishing fleet numbered about
    four million vessels.
  • In 2005
  • 100 million tons taken
  • 70 billion

3
Global Fish Catch
4
Emptying the oceans
  • We are placing unprecedented pressure on marine
    resources
  • Half the worlds marine fish populations are
    fully exploited
  • 25 of fish population are overexploited and
    heading to extinction
  • Total fisheries catch leveled off after 1998,
    despite increased fishing effort
  • It is predicted that populations of all ocean
    species we fish for today will collapse by the
    year 2048

5
Fish Population Estimates
6
We have long overfished
  • People began depleting sea life centuries ago
  • Some species hunted to extinction Stellers sea
    cow, Atlantic gray whale, Caribbean monk seal
  • Overharvesting of Chesapeake Bay oyster beds led
    to the collapse of its fishery, eutrophication,
    and hypoxia
  • Decreased sea turtle populations causes
    overgrowth of sea grass and can cause sea grass
    wasting disease
  • People never imagined that groundfish could be
    depleted
  • New approaches or technologies increased catch
    rates

7
Fishing Techniques
8
  • 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

9
Gillnetting
Uses curtains of netting suspended by a system of
floats and weights Either anchored to sea floor
or float at the sea surface Netting is almost
invisible, fish swim right into it and their
gills get caught
net size 20 m x 65 km
10
Drift Netting
Driftnets have earned the nickname walls of
death.
  • Large floating nets
  • Unbreakable and invisible to most sea species
  • likely to entangle large pelagic
    speciesdolphins, whales, sharks, turtles, and
    rays.

11
Longlining
  • Longlines are horizontal sets of fishing hooks
  • Set on the ocean floor demersal longlines
  • Set near the surface pelagic longlines
  • Longlines can be tens of kilometres long
  • Can carry thousands of hooks
  • Baited hooks are attached to the longline by
    short lines called snoods that hang off the
    mainline.

12
  • Not anchored set to drift near the surface of
    the ocean
  • Attached radio beacon tracks line to haul in
    catch
  • Usually used to catch large tuna and billfish
    species.

13
  • Anchored to the sea floor.
  • Buoys mark line
  • Same as Pelagic longline in all other respects

14
Purse seine
  • Uses large wall of netting to encircle schools of
    fish
  • Drawstring pulls bottom of netting closed, like a
    purse
  • Herds schools of fish into center
  • Some purse seines can unintentionally catch other
    animals (dolphin caught when fishing for tuna)

Animation
15
Trawl
bottom
midwater
http//www.youtube.com/watch?vbUHcD_jTgVA
16
Effects of Trawling on Coral Reefs
http//www.eea.europa.eu/publications/report_2002_
0524_154909/regional-seas-around-europe/page111.ht
ml
17
Trawl from space
Gulf of Mexico, near Louisiana coast. Individual
vessels can be seen as bright spots at end of
sediment trails. Other bright spots are fixed oil
and gas production platforms. One sediment trail
can be traced for 27 km. Assuming a standard
trawling speed of 2.5 knots, sediment from this
trawl is visibly persistent for nearly 6 hours.
Water depth lt20m. Large, indistinct bright blue
patches at lower left and upper right are
cloud/haze. (Credit Landsat)
18
Sonar
  • Uses sound waves that allow fishermen to quickly
    locate fish and/or see the bottom
  • Targets specific species

Image http//www.marinesonic.com
19
Factory Ship
Courtesy of Wikipedia Commons
  • Can haul in LARGE quantities of fish
  • Can process and freeze fish onboard
  • Up to 60 - 70 meters long
  • Can be at sea for six weeks at a time with a crew
    of over 35 people.
  • Types demersal (weighted bottom trawling)
  • pelagic (mid-water trawling)
  • pair trawling, two vessels, 500 metres apart,
    both pull huge net with a mouth circumference of
    900 meters

20
Pole / Troll
  • Uses fishing pole and bait to target fish
  • Environmentally responsible alternative to
    longlining
  • pole/troll fishermen have very low bycatch rates.

21
Fisheries Problems
Solutions
22
Fisheries mismanagement
  • Overfishing
  • Commercial extinction
  • Bycatch (27 million metric tons annually)
  • Targeting smaller species on the low end of the
    food chain

23
  • 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)

24
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
25
  • Allows smaller fish to be caught
  • Allows turtles to escape
  • Lowers incidence of bycatch

26
  • Same concept as TEDs
  • Hatch kept open with inflatables

27
Modern fishing fleets deplete marine life rapidly
  • Grand Banks cod have been fished for centuries
  • Catches more than doubled with immense industrial
    trawlers
  • Record-high catches lasted only 10 years

28
Bycatch by Gear Type for 2002/2003
29
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
30
Fisheries Problems Solutions Driftnets
indiscriminate entangling of many sorts of marine
animals SOLUTION banned in oceanic fisheries
(but some countries still using them)
31
  • Fisheries Problems Solutions
  • 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.

32
Global swordfish catch
Ave. wt. in lbs
http//www.pifsc.noaa.gov/wpacfin/hi/dar/Pages/hi_
fish_2.php
year
33
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
34
AquaCulture
35
Aquaculture (marine agriculture)- farming
finfish, shellfish and algae under favorable
conditions
36
One of every four fish eaten today was raised
in either a fw or sw fish farm.
37
  • Aquaculture also produces
  • Bait fish
  • Ornamental or aquarium fish
  • Aquatic animals used to augment natural
    populations
  • Algae for chemical extraction
  • Pearl oysters

38
  • History
  • 2000 years ago in Egypt, Rome, China
  • lt2000 years in Hawaii
  • 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

39
Criteria for selecting species for
farming - inexpensive to grow - grows
quickly - high sales price - resistant to
disease and parasites
40
(No Transcript)
41
Hawaii open ocean aquaculture
Mio, big eye tuna, yellow tail
34.7 million in 2008
42
Industrialized fishing depletes populations
  • Catch rates drop precipitously with
    industrialized fishing
  • 90 of large-bodied fish and sharks are
    eliminated within 10 years
  • Populations stabilize at 10 of their former
    levels
  • Marine communities may have been very different
    before industrial fishing
  • Removing animals at higher trophic levels allows
    prey to proliferate and change communities

43
Several factors mask declines
  • Industrialized fishing has depleted stocks,
    global catch has remained stable for the past 20
    years
  • Fishing fleets travel longer distances to reach
    less-fished portions of the ocean
  • Fleets spend more time fishing and have been
    setting out more nets and lines, increasing
    effort to catch the same number of fish
  • Improved technologies faster ships, sonar
    mapping, satellite navigation, thermal sensing,
    aerial spotting
  • Data supplied to international monitoring
    agencies may be false

44
We are fishing down the food chain
  • Figures on total global catch do not relate the
    species, age, and size of fish harvested
  • As fishing increases, the size and age of fish
    caught decline
  • 10-year-old cod, once common, are now rare
  • As species become too rare to fish, fleets target
    other species
  • Shifting from large, desirable species to
    smaller, less desirable ones
  • Entails catching species at lower trophic levels

45
Consumer choices influence fishing practices
  • Buy ecolabeled seafood
  • Dolphin-safe tuna
  • Consumers dont know how their seafood was caught
  • Nonprofit organizations have devised guides for
    consumers
  • Best choices farmed catfish and caviar,
    sardines, Canadian snow crab
  • Avoid Atlantic cod, wild-caught caviar, sharks,
    farmed salmon

46
The Big Question
  • Fish Populations are declining
  • The Human Population is increasing exponentially
  • What can be done to sustain fish as a viable food
    resource for the human population?
  • What YOU can do Choose to eat sustainably
    harvested seafood

47
Aquaculture Methods
Is Aquaculture the Answer?
48
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49
Relevant Laws
  • UN Law of the Seas
  • Magnuson-Stevens Fisheries Management and
    Conservation Act (Magnuson Act)
  • Marine Sanctuaries Act
  • Oceans Act of 2000
  • Endangered Species Act (ESA)
  • Convention on International Trade in Endangered
    Species (CITES)
  • Lacey Act of 1900

50
Laws Related to Fishery Management
  • UN Law of the Seas
  • Nations have jurisdiction over Exclusive Economic
    Zones (200 Miles)
  • Sea Floor sovereignty up to 12 miles offshore
  • Allows for Individual Transferable Quotas which
    can be sold to others
  • Magnuson Act
  • Establishes 200 mile fishing area
  • Set up regional councils that
  • Set quotas
  • Set size limits
  • Set seasons
  • Protects habitat
  • Minimizes bycatch
  • Rebuilds overfished stocks

51
Fisheries management
  • Based on maximum sustained yield
  • Maximal harvest while keeping fish available for
    the future
  • Managers may limit the harvested or restrict gear
    used
  • Despite management, stocks have plummeted
  • It is time to rethink fisheries management
  • Ecosystem-based management
  • Shift away from species and toward the larger
    ecosystem
  • Consider the impacts of fishing on habitat and
    species interactions
  • Set aside areas of oceans free from human
    interference

52
We can protect areas in the ocean
  • Marine protected areas (MPAs) established along
    the coastlines of developed countries
  • Still allow fishing or other extractive
    activities
  • Marine reserves areas where fishing is
    prohibited
  • Leave ecosystems intact, without human
    interference
  • Improve fisheries, because young fish will
    disperse into surrounding areas
  • Many commercial, recreation fishers, and
    businesses do not support reserves

53
Reserves work for both fish and fisheries
  • Found that reserves do work as win-win solutions
  • Overall benefits included
  • Boosting fish biomass
  • Boosting total catch
  • Increasing fish size
  • Benefits inside reserve boundaries included
  • Rapid and long-term increases in marine organisms
  • Decrease mortality and habitat destruction
  • Lessen the likelihood of extirpation of species

54
Areas outside reserves also benefit
  • Benefits included
  • A spillover effect when individuals of
    protected species spread outside reserves
  • Larvae of species protected within reserves seed
    the seas outside reserves
  • Improved fishing and ecotourism

55
How should reserves be designed?
  • 20-50 of the ocean should be protected in
    no-take reserves
  • How large?
  • How many?
  • Where?
  • Involving fishers is crucial to fisheries to
    determine the answers

56
Laws Related to Habitat Protection
  • Marine Sanctuaries Act
  • Protects habitat of marine organisms
  • Protects animals from being harvested in that area
  • Oceans Act of 2000
  • Established Presidential Commission to
  • Examine Federal Ocean Policy
  • Promote protection of marine environments
  • Prevent marine pollution

57
Laws Related to Species Protection
  • CITES
  • Identifies and lists endangered species
  • Prohibits international trade in listed species
  • ESA
  • Identifies and lists endangered species
  • Prohibits the harm or harvesting of listed
    species
  • Protects habitat
  • Lacey Act of 1900
  • Prohibits sale of illegally harvested species
  • Forces legal methods

58
Conclusion
  • Oceans cover most of our planet and contain
    diverse topography and ecosystems
  • We are learning about the oceans and coastal
    environments, intensifying our use of their
    resources, and causing severe impacts
  • Setting aside protected areas of the ocean can
    serve to maintain natural systems and enhance
    fisheries
  • We may once again attain the ecological systems
    that once flourished in our waters

59
QUESTION Review
  • Which of the following does not mask the decline
    of fisheries?
  • Fishing fleets travel longer distances
  • Fishing fleets spend more time fishing
  • Fishing fleets use traditional methods of fishing
  • Data supplied to monitoring agencies may be false

60
QUESTION Review
  • Marine reserves have all the following benefits
    except
  • Fishing increases in the reserve
  • The size of fish increases
  • Larvae can seed areas outside the reserve
  • Decreased mortality and habitat destruction

61
QUESTION Interpreting Graphs and Data
  • What does this graph show about the future of
    global fisheries catch?
  1. China will be a major player in applying fishing
    pressure
  2. China will be playing a smaller role in applying
    fishing pressure
  3. The world will decrease its fishing pressure
  4. The U.S. is not included in this graph

62
QUESTION Interpreting Graphs and Data
  • Which conclusion can you draw from this graph?
  1. Oceans today contain far fewer fish
  2. Oceans today contain far more fish
  3. It is easier to find fish today
  4. There is little correlation between fishing and
    fish stocks

63
QUESTION Viewpoints
  • If a developer wants to build a community on an
    estuary, providing jobs but eliminating the
    marsh, what should be done?
  • Let the developer build we need the jobs
  • Let the developer build, but make him/her pay for
    any damage from storms
  • Let the surrounding landowners vote whether to
    let the developer build
  • Prevent the development the potential damage is
    too great

64
QUESTION Viewpoints
  • Do you plan to alter your decisions about eating
    seafood?
  • Yes I will be more selective about what I eat
  • No I will continue to eat the same type and
    amount of seafood as always

65
(No Transcript)
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