overfishing training

2. • Traditional food production and
distribution practices are unable
to feed the world’s 6.3+ billion
people
• Will resources in the sea be able
to provide enough food to
alleviate future problems of
malnutrition and starvation ?

3. Most valuable living marine resources:
• Demersal fish
• Pelagic fish
• Crustaceans
• Mollusks
• Marine mammals

4. Location of the world’s major commercial fisheries
upwelling
coastal areas

5. 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

6. Global Fish Catch

8. 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

10. Food from the Sea
• Seaweeds
• Invertebrates (e.g., oysters, clams, crabs,
lobster, squid, etc.)
• Fish (herring, mackerel, haddock, cod,
tuna, mahi-mahi, etc.)

11. Fisheries management
• Fisheries management
seeks to maintain a long-
term fishery by:
– Assessing ecosystem
health
– Determining fish stocks
– Analyzing fishing
practices
– Enforcing catch limits
• Fisheries management
does not regulate the
number of fishing
vessels

12. Fisheries Mismanagement

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

14. Bycatch by Gear Type for 2002/2003

15. Peru Anchovy Fishery

16. 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

17. = El Niño
1957
1965
1972
1976
1982-83
Peru Anchovy Fishery

18. Collapse of New England
Fisheries
• Cod, haddock, ocean perch, herring,
mackerel, blue fin tuna
• George’s Bank- highly productive,
nutrient rich environment
• Prior to 1976, Russia, Japan, Norway,
& West Germany fished in Georges
Bank

19. 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

20. Alaska Fisheries
• Halibut and sablefish
• IFQ
• Limited entry c1930’s

21. Shark Overfishing
• Slow growth
• Low reproductive rate
• Late sexual maturity

22. 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

24. Fishing Techniques

25. Fishing Methods
• Harpoon - whales, swordfish, bluefin tuna
• Pole and line - mahi-mahi and used for tuna
extensively in the 50‘s
• 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

26. Drift Net
net size:
20 m x 65 km

27. Longlining

28. Gill net
Bottom-dwelling fish

29. Purse seine

30. Trawl
midwater
bottom
http://www.youtube.com/watch?v=bUHcD_jTgVA

31. Before trawl
After trawl

32. 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 <20m. Large, indistinct bright blue patches at lower left and
upper right are cloud/haze. (Credit: Landsat)

33. Exclusive Economic Zone (EEZ)
1. 200 nautical miles
2. under direct control of the country that owns the
nearest land
Allow nations to claim jurisdiction over their territorial
seas (contiguous sea beds and their waters that
extend off shore by 12 nautical miles)
Regulates continental shelf resources:
• Fishing
• Mineral exploration
• Scientific research

34. Exclusive Economic Zone of the United States

37. Fisheries Problems & Solutions
A. Maximum sustainable yield: maximum amount of
fish that can be harvested without depleting
future stocks
B. World‘s maximum sustainable yield estimated at
100 to 135 million metric tons
C. Present harvests are at about 100 million metric
tons
D. For fisheries where numbers available,
estimated that 45% are currently over-fished
E. A number of fisheries have already collapsed
(Anchovy fishery off Peru, Cod fishery in the N.
Atlantic)

38. 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

39. Dolphins caught in tuna net
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

40. Fisheries Problems & Solutions
Driftnets: indiscriminate entangling of many sorts of
marine animals
SOLUTION: banned in oceanic fisheries (but some
countries still using them)

41. 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.

42. Global swordfish catch
http://www.pifsc.noaa.gov/wpa
cfin/hi/dar/Pages/hi_fish_2.php
0
50
100
150
200
250
300
350
400
450
1817 1861 1900 1961
N. Atlantic
Swordfish
Ave.
wt.
in
lbs
year

44. Mariculture or Aquaculture
(marine agriculture)- farming
finfish, shellfish and algae under
favorable conditions
Big Island, Kona, Tilapia

45. One of every four
fish eaten today was
raised in either a fw
or sw fish farm.

46. 84% of the 6 million to 7
million tons of seafood
consumed each year in the
U.S. is imported . About ½
comes from aquaculture.
H. Jones, Time, 2011.

49. Aquaculture also produces:
• Bait fish
• Ornamental or aquarium fish
• Aquatic animals used to
augment natural populations
• Algae for chemical extraction
• Pearl oysters

50. Criteria for selecting species for
farming:
- inexpensive to grow
- grows quickly
- high sales price
- resistant to disease and parasites
tilapia barramundi catfish

51. Problems associated with Mariculture:
• Won’t make a dent in the shortfall in food
supply
• Fish food- fish meal
• Pollution
• Escapees
• Loss of natural habitat
• Loss of genetic diversity
• High stress overcrowding pens
• High concentration of
pathogens/parasites

52. Overcrowded Pens

53. Salmon with lice
Parasites & Disease

54. Pollution Under a salmon farm cage

55. Fish Vaccination

56. Integrated Aquaculture
Aquaponics

57. Hawaii open ocean aquaculture
Mio, big eye tuna, yellow tail
$34.7 million in 2008

58. Artificial Reefs
Improve the local marine bio-density
1. attract schools of fish
2. providing habitats for the colonization
of commercially valuable species
3. improve the local inshore marine
harvest
May wash up
on beaches
tires ship wrecks construction rubble

59. Threat to Marine Life
• Commercial fishing operations
• Pollution
• Habitat Degradation
• Trampling and beach combing
• Climate Change

60. Threat to Marine Life
• Commercial fishing operations
– Overfishing
– Discards
– Bycatch
– Ghost fishing
– Use of deleterious fishing gears

61. Threat to Marine Life
Overfishing –

62. Threat to Marine Life
Overfishing –

63. Threat to Marine Life
Discards

64. Threat to Marine Life
Bycatch

65. Cod End of Trawl Net
Threat to Marine Life
Use of small mesh

66. Threat to Marine Life
Deleterious fishing

67. Threat to Marine Life
Deleterious fishing gears in Nursery

68. Threat to Marine Life
Deleterious fishing gears in Nursery

69. Threat to Marine Life
High bycatch

70. Threat to Marine Life
Non Target Species

71. Threat to Marine Life
Non Target Species

72. Threat to Marine Life
• Pollution
– Sewage Pollution
• Domestic sewage
• Industrial sewage
– Oil Pollution
– Solid waste disposal
– Thermal Pollution
– Light Pollution

73. Threat to Marine Life
Sewage Pollution

74. Threat to Marine Life
Sewage Pollution

75. Threat to Marine Life
Sewage Pollution

76. Threat to Marine Life
Oil Pollution

77. Threat to Marine Life
Oil Pollution

78. Threat to Marine Life
Solid Waste Disposal

79. Threat to Marine Life
Thermal Pollution

80. Threat to Marine Life
Light Pollution: Gwader by
night

81. Threat to Marine Life
• Habitat Degradation
– Mangrove denudation
– Land reclamation
– Port Development

82. Threat to Marine Life
Mangrove denudation

83. Threat to Marine Life
Land reclamation

84. Threat to Marine Life
Port Development-Sonmiani (Damb)

85. Threat to Marine Life
• Trampling and beach combing
– Trampling
– Stone turning
– Disturbance to animals
– Beach Combing

86. Threat to Marine Life
Trampling

87. Threat to Marine Life
Disturbance to Marine Animals

88. Threat to Marine Life
• Climate Change
– Seawater intrusion
– Frequent cyclone
– Unpredictability of weather
– Sea Level Rise

89. Threat to Marine Life
Frequent Cyclone – 2A Cyclone
1999

90. Threat to Marine Life
Frequent Cyclone – Increased
Frequency

91. Threat to Marine Life
Seawater Intrusion: Indus
Creeks

92. Threat to Marine Life
Frequent Cyclone- Phet Damage
at Jiwani

93. Threat to Marine Life
Sea level Rise-Damb 2006

94. Threat to Marine Life
Sea level Rise-Damb- 2012

97. THANKS