chapter 4.3

Question 1

What are primary producers in food web?

Answer 1

Phytoplankton (microscopic marine algae)
Macrophytes (plants visible without microscope)
Cyanobacteria (bluegreen)

Question 1

How does energy get into the aquatic food web?

Answer 1

Photosynthesis by phytoplankton supports a highly diverse range of food webs.

Question 2

What are zooplanktons?

Answer 2

Zooplanktons are single celled animals that are primary consumers of phytoplankton

Question 3

What do you understand by the term Fisheries?

Answer 3

Place where fish are caught

Question 4

Define Capture Fisheries and Aquaculture

Answer 4

Capture Fisheries : WIld Fisheries
Aquaculture : Farm Fisheries

Question 5

List factors affecting human consumption of fish and seafood

Answer 5

Shift in dietary choices
Efficiency of fisheries
Aquaculture
Affordabliity
Distribution of aquatic products

Question 6

List and Explain Methods of Fishing

Answer 6

Dredging : dragging metal bags across ocean floor.
Trawling : dragging net through water
Gill Nets : Curtain of netting placed in the water with small holes.
Blast Fishing : using explosives to kill and capture fish
Ghost fishing : abandoned fishing gear.

Question 7

What is a sustainable fish? (wild)

Answer 7

A fish that is harvested using minimal effect to the long term survival of its species and minimal bycatch

Question 8

What is bycatch?

Answer 8

Other catch which is not the target

Question 9

Define maximum sustainable yield?

Answer 9

Sustainable Yield is the increase in natural capital (i.e natural income) that can be exploited every year without depleting the original stock or its potential for replenishment. For commericial ventures, the maximum sustainable yield (MSY) is of interest since it shows the maximum amount of fish they can harvest before it turns into over fishing (eg).

Diagram on page number 404.

Question 10

Write down 4 examples of how climate change affects oceans.

Answer 10

Thermal Expansion
Melting Ice on Land
Heat Waves and Acidification
Biodiversity reduced
Effects on precipitation
Decrease in salinity of water
Changes the lives of human coastal communities
Increases the temperature and the transmission of diseases.

Question 11

Define Ocean Acidification

Answer 11

Through the exposure of gases such as carbon dioxide to oceans, the waters absorb carbon dioxide and turn more acidic, with more hydrogen ions. When the pH of seawater decreases, it is called as ocean acidification. (Carbonate Ions +++)

Question 12

List & Explain any 2 solutions of unsustainable exploitation

Answer 12

Rights-Based Fishery Management : first come first serve basis. Fishers can catch as many fishes they want in the shortest time possible. This is basically allocating certain times to an entity for when they can fish, where they can fish and for how long they can fish. They have to adhere to the limits given to them. This balances socio-economic and ecological needs.

Fishing Subsidies : Subsidies are given for fuel, fishing gear and building new vessels. They are seen as an incentive to overfish at a time when estimates suggest there are already two and a half times more fishing fleets than are needed to meed demand.

Regulations : Regulations can be applied at any level. Managing them is not easy

Ban fishing in international waters : International waters are not owned by any country so anyone can fish there without restrictions. If collectively people ban fishing here this could lead to less overfishing.

Protecting predator species : If we overfish predator species then there will be no one to maintain the food chain. Hence, we should protect these species since they are crucial for the wildlife.

Traceability and Food Labeling : This requires that food is labeled from where it comes from therefore the journey of the catch to the consumer is known by all stakeholders involved. The consumer can then make an educated choice about their food choices.

Question 13

Define Aquaculture

Answer 13

Aquaculture is the farming of aquatic organisms in either coastal or inland areas; it involves interventions in the rearing process to enhance production.

Question 14

What are the disadvantages of fish farms (List 3)

Answer 14

Loss of habitats
Pollutions (with feed, antifouling agents, antibiotics and other medicines added to fish pens)
Spread of Diseases
Escaped species, including GMOs, may survive to interbreed with wild fish or outcompete native species and cause the population to crash

Question 15

List 2 Adv of Aquaculture

Answer 15

Adv :
More sustainable because…
1. Fishmeal using scraps that were wasted in past (fish obtained from bycatch)
2. Waste products from livestock of poultry industry used instead of fishmeal
3. Many carnivorous fish are able to obtain enough energy from other sources instead of eating other fish.
4. Less food and Less Energy is used to harvest fish.