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MARE 171 > Chapter 19 > Flashcards

Chapter 19 Flashcards

1
Q

Harvesting the Oceans Resources

A

Sea has been a major source of food for human populations
- new source of natural resources over past 100 years
- many are concerned about increased development along with increased fishing pressure

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2
Q

Commercial Fishing dooms day study

A

A study released in 2006 reported that by 2048 most commercially fisheries will collapse due to overfishing

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3
Q

Humans have harvested fish and shellfish (invertebrates) from oceans for thousands of years but there has been A

A

dramatic increase in past 50 years

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4
Q

Over the past 50 years there has been a change in how fisheries catch has been used

A

1950: 90% human consumption; 10% feed
1988: 60% human consumption; 40% feed

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5
Q

Renewable Resources

A

resources that can replenish themselves
- animals not caught can replace those that were

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6
Q

The goal of fisheries management is to maintain these resources by:

A

Enacting policies on fishing practices
Setting catch limits

If done correctly should:
Prevent overfishing to the point of extinction
Allow enough animals to survive and reproduce
Allow for fisheries to be sustainable in the future

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7
Q

Stocks

A

a separate population of fish that is assumed to be reproductively isolated from others in the range

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8
Q

Tagging

A

a procedure for monitoring the distribution and movement of animals in the environment

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9
Q

Landings

A

the catch made by fishing vessels

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10
Q

Fishing effort

A

a measure of the number of vessels fishing, the number of fishers working, and the number of hours spent fishing
- Catch Per Unit Effort (CPUE)

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11
Q

Potential Yield

A

the number of pounds of fish or shellfish a stock can yield annually without being overexploited

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12
Q

Sustainable Yield

A

the maximum yield over several years that will not stress a stock

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13
Q

Surplus population models

A

– used to search for the largest fishing mortality rates that can be offset by increased population growth, normally measured in changes in population biomass per unit time

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14
Q

Complex calculations based upon several life history parameters, including:

A

population density
population biomass
population growth rate

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15
Q

If quota set too high:

A

yield would exceed the surplus population so the population would be driven to extinction

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16
Q

If quota set too low:

A
  • will stabilize and yield lower than BMSY or
  • will become unstable and either increase to equilibrium at the higher population size or crash
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17
Q

Biological interactions

A

mean that population dynamics of different species are inevitably linked

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18
Q

Overfishing

A

is catching fish faster than they can reproduce and replace themselves

At least 60% of the world’s 200 most valuable species are currently overfished

Overfishing can cause changes in:
- Genetic diversity
- Species diversity
- Habitat

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19
Q

Trawl Nets

A

are large nets that are dragged along the sea bottom

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20
Q

Gillnets

A

made from monofilament line continue catching for hundreds of years

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21
Q

Bottom Trawls

A

can stir up sediment and destroy bottom substrates

22
Q

Exclusive Economic Zone (EEZ):

A

is the area of ocean that a coastal nation controls

23
Q

Law Of the Sea (1977)

A

established 200-mile-wide Exclusive Economic Zones (EEZ)
granting coastal nations exclusive rights with respect to natural resources

24
Q

Surimi

A

is a fishery product made from Alaskan Pollock
- fats and oils removed; flavor added back to mimic shellfish

25
Q

Incidental Catch (Bycatch)

A

the non-commercial animals that are killed during fishing for commercial species

26
Q

Trash Fish

A

the term used for incidental catch that is solely fish

27
Q

Inefficient use of catch: Shark Finning

A

100 million sharks are killed each year
Estimates are between 63-273 million per year

28
Q

Drift Nets

A

are large nets that may stretch for as much as 60 kilometers

29
Q

Tans

A

are individual sections of a drift net

30
Q

Case Study mackerel and red snapper

A

GOM shrimp fisheries discarded 19 million red snapper and
3 million Spanish mackerel

31
Q

Aquaculture (Mariculture):

A

the use of aquaculture techniques to breed and raise marine organisms

32
Q

Monoculture

A

the process of raising a single species in aquaculture

33
Q

Polyculture

A

the process of raising several species together in aquaculture

34
Q

Raft Culture

A

a form of aquaculture in which juveniles of commercially valuable molluscs are attached to ropes suspended from rafts

35
Q

Eco-Friendly Aquaculture

A

is a type of aquaculture where the growing of fish or shellfish do not have negative impacts on the environment; sometimes positive

36
Q

Eco-Friendly Aquaculture Often involves

A

Using waste to produce food for animals
- sewage to grow algae to feed oysters
Using waste a fertilizer for plants
- shrimp farm waste to fertilize adjacent fields
3) Using animals to minimize waste back to sea
- bivalves to clean waste water before return

37
Q

Problems with Aquaculture

A

Pollution
- nutrients
food waste
animal waste
- drugs & chemicals
2) Wild fish caught to feed cultured fish
- global production decreases
3) Invasive species
- impact foodwebs
- cause disease

38
Q

Purse seines

A

are huge nets that can be closed by pulling on a line; similar to the way a purse or a bag of marble is closed

39
Q

Backing Down

A

a technique in which the skiff setting the purse seine backs up, causing the edge of the net to drop beneath the surface of the water, allowing dolphins to escape

40
Q

Ocean Ranching (sea ranching):

A

a process in which young fish are raised in pens and then returned to the sea to supplement natural populations
- ½ fish commercially caught are hatchery fish

41
Q

Desalination

A

the process of removing salt from seawater

42
Q

Sulfides

A

minerals containing sulfur
include gold, silver, platinum etc…
Manganese - estimated 16 million metric tons on ocean floor

43
Q

Fossil Fuels

A

are fuels formed from the remains of organisms that lived millions of years ago

44
Q

Methane Hydrate

A

is ice that holds methane gas

45
Q

Case Studies
Anchovies

A

Anchovies represent worlds largest catch of a single species; Changes is ocean production (El Nino) coupled with overfishing caused a crash in the fishery

46
Q

Case Studies Tuna

A

Tuna are a global fishery with over 4.6 million tons annually harvested in the US

Depending upon species and location tuna are either:
Longlined – yellowfin, bigeye, albacore
Hand lined – Bluefin, albacore
Purse seined – yellowfin, bluefin

47
Q

Case Studies
Marine Mammal Protection Act

A

1972
to reduce the number of marine mammals, including dolphins killed in fisheries

Implemented several changes to purse seining methods and equipment including a Backing Down procedure

48
Q

Case Studies
Salmon

A

Salmon are an important fishery in the US
Pacific Salmon – Pacific NW & Alaska
Atlantic Salmon – N. Atlantic & Farmed

Due to high demand for fish and increased pressure upon wild stocks; fish in Pacific NW & Alaska are reared in hatcheries and released to supplement wild stocks
- ½ fish commercially caught are hatchery fish

49
Q

Case Studies
Shellfish

A

represent a large amount of the commercial catch in the world
- 7 million metric tons molluscs
- 5.5. million metric tons crustaceans

50
Q

Mineral Resources

A

30% of the worlds supply of Salt (NaCl)
200 million metric tons annually
60% of the worlds supply of Magnesium
70% of the worlds supply of Bromine

10 million tons of Gold
4 billion tons of Uranium
51
Q

Most widespread seafloor mining is to extract sand and gravel for:

A

cement
- concrete
- replenishing natural beaches
- creating artificial beaches

52
Q

Oil and Natural Gas

A

90% of the value of minerals taken from the sea - formed from remains of microorganisms like diatoms
Annual revenue of offshore production is over $100 Billion

MARE 171 (10 decks)

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