IB ESS HL 4.3 Aquatic Food Production Systems Question Bank

algae/seaweed/sea grass;

increased food demand from increasing population/affluence; health benefits / change of diet preferences;
depletion of marine fisheries / considered more sustainable;
limited arable land for food production;
more economically efficient/profitable; requires less resources/expertise (boats, fishermen, etc) than wild fisheries; technology/technological methods have improved;

Marking guidance:

Award [1 max].

escaped fish impact wild stocks through genetic degradation/disease/competition; high density populations lead to more disease; farmed species may consume/displace food species for local populations; loss/degradation of habitat due to clearance for aquaculture / nets/cages may trap/endanger local species; introduction of non-native species; pollution due to use of medication/growth hormones/pesticides;

NB do not credit high nutrients/eutrophication/low diversity/high BOD or any other impacts that integrated agriculture actually limits or reduces (as indicated in responses to 3d below).

Marking guidance:

Award [1] for each correct answer identified, up to [2 max].

polyculture helps maintain biodiversity/complexity/resilience in the environment; (polyculture) allows for species to recycle wastes of other species; lobsters/mussels will reduce particles of organic waste/faecal matter/excess feed; (reduction of particles will) reduce BOD/decomposition and oxygen consumption; filtration by the mussels will improve water clarity/photosynthesis; cropping/harvesting algae will prevent build-up of nutrients/eutrophication; algae will absorb excess $\mathrm{CO}_{2}$ reducing acidification of water; algae will release oxygen limiting anaerobic conditions; food is provided naturally from within system/feeds made up from wild populations are not required;

Marking guidance:

Award [1] for each correct answer identified, up to [4 max].

Part (c) questions in Section B are all to be assessed using the markbands on page 21 with the guidance given below for each question.

Identify the category with the lowest global harvest weight from aquaculture in Figure.

Marine fish;

(105 million - 58 million) 47000000 / 47 million (T) (accept 44-50 million T );
Note to examiners: Do not accept \% value. Units (T) are not required for credit in this question.

a. Rising world population causes increased demand for food;
b. Greater demand for high protein foods;
c. Improved technology and techniques for catching/aquaculture of freshwater fish;
d. Greater desire/interest in some countries for locally caught/harvested foods;
e. Depleted stocks of wild fisheries;

Describe two possible reasons for the difference in global aquaculture harvest between marine fish and molluscs in Figure.
a. Molluscs are easier to farm than marine fish / marine fish are more easily captured in wild';
b. some molluscs are small and less mobile, and so require less area to culture;
c. Molluscs and their resources/conditions are easier to control than marine fish;
d. Different species of molluscs can be raised in both freshwater and marine aquaculture environments;
e. Some molluscs reach maturity for harvesting faster than marine fish / high turnover rate leads to larger harvest;
f. Market price (per unit weight) is higher for molluscs making aquaculture a profitable choice;

Note to examiners: Award credit for converse of MPs b-f (as in MPa).

Pros [3max]:
a. Seafood demand is expected to rise significantly by 2050 , so it can provide new/more sources of food;
b. Aquaculture harvest would reduce stress on wild fisheries/farming land;
c. Provides economic opportunities for coastal nations, particularly developing nations;
d. Waste and nutrients can be cycled, making it more sustainable / usually reduces food miles;
e. More than one species can be harvested in Integrated multi-trophic aquaculture (IMTA);
f. Many forms of seafood have a high protein value;
g. Aquaculture, usually, is more efficient (economically, ecologically) than capture;

Cons [3max]:
a. May lead to loss of habitat in certain ecosystems;
b. Greater localized aquatic pollution (antibiotics, medicines, nutrient pollution, etc.);
c. Spread of diseases and escaped species (some involving genetically modified organisms);
d. Ethical concerns towards mass fish farming or genetically modified organisms (GMOs);
e. It is not economically viable to farm large marine species like tuna with aquaculture;
f. May raise local water conflicts;
g. Difficult to certify for sustainability/social responsibility;
h. Current frameworks suit better, in most case, large-scale industrial aquaculture (rather than small-scale farmers);
i. Current share of marine fish coming from aquaculture suggests it is unpopular; j. Aquaculture has high set-up/maintenance costs / requires a lot of resources i.e. fish feed/antibiotics;

Note to examiners: Credit any valid advantage or disadvantage. Do not credit simplistic arguments, like more costly, more sustainable, more efficient, etc.

Credit other valid responses