1. Aquatic Food Production Systems 4.3

2. Applications and Skills
Discuss with reference to a case study the controversial harvesting of a named species
Evaluate strategies that can be used to avoid unsustainable fishing
Explain the potential value of aquaculture for providing food for future generations
Discuss a case study that demonstrates the impact of aquaculture

3. Marine Ecosystems Marine ecosystems include:
Oceans
Mangroves
Estuaries
Lagoons
Coral reefs
Deep ocean floor
Half of marine productivity is in coastal regions above the continental shelf
Continental shelf is an extension of continents and creates shallow water

4. Marine Ecosystems
Shallow water from continental shelves are important:
50% of oceanic productivity but 15% of its total area
Upwellings bring nutrient rich water up to the continental shelf
Light reaches shallow areas which helps photosynthesis
Counties can use to exploit and harvest
Deep ocean is not as productive (less light)

5. Marine Ecosystems
The UN Convention on the Laws of the Sea (UNCLOS) in 1982 designated continental shelves as belonging to the country from which they extend
Also designated 370 km limit from the low water mark of the shore as exclusive economic zone belonging to the country

6. Marine Ecosystems
Outside these boundaries are international waters which no country controls
Creates huge implications:
Who fishes there?
Who controls them?
Who cleans up pollution problems?
Tragedy of the commons......

7. Marine Ecosystems

8. Marine Ecosystems
Phytoplankton: single celled photosynthetic organisms that are the most important producer in the oceans
Responsible for 99% of primary productivity
Zooplankton: single celled animals that eat phytoplankton and their waste (DOM)
These organisms support
the complex food web of
the oceans
Both float in the water

9. Marine Food Chain and Webs
Phytoplankton and zooplankton help to support a complex interconnected set of marine food webs

10. Marine Ecosystems Marine organisms can be classified as:
Benthic –living on or in the sea bed (Benthos)
Pelagic –living surrounded by water from above the sea to the surface

11. Fisheries
Fishery: exists when fish are harvested in some way. Includes capture of wild fish and aquaculture or fish farmin
Aquaculture: the farming of aquatic organisms in both coastal and inland areas involving interventions in the rearing process

12. Fisheries About 90% of fishery activity is in oceans and 10% in FW
Include oysters, mussels squid and molluscs, eels, tuna, etc

13. Methods of Fishing
Some commercial fishing methods are not sustainable and are very environmentally damaging
Dredging: drags a metal bag across the ocean floor. Captures everything in path
Gillnets: a curtain of netting is placed in the water with holes large enough for fish to get head but not body through. Large rates of bycatch
Trawling: drags a net through the water behind a boat. Captures any organism in path
Blast Fishing: using explosives to kill fish in area. Kills all life in area and damages coral

16. Fisheries Up to 0.5 billion people’s livelihoods
3 billion people gain 20% of their protein from fish, the rest ~15%
Fish is a good source of lean protein (important)
Per Food and Agriculture Organization (FAO): 70% of the world’s fisheries are fully exploited, in decline, seriously depleted, or too low to allow recovery
Global fish catch is no longer increasing even with better technology

17. Fisheries

18. World Aquaculture Production

19. Fisheries

20. Aquaculture
Many people in MEDC’s are opting for healthier protein (fish) than terrestrial animals
Worldwide, avg person eats 20kg of fish and 8 kg of meat per year

21. Aquaculture
As demand for fish has increased, the extra fish comes from fish farms
Wild caught fish have reached its limit even with better technology to find fish
Either the fish just are not present because of exploitation or we cannot take more than the sustainable yield (not enough with increasing population
We will now be eating more farmed fish than wild caught fish

22. Aquaculture - Benefits
Ways in which fish farming is becoming more sustainable:
Fishmeal formula includes more scraps that were once waste
Livestock and poultry waste substitute for fishmeal
USDA has shown 8 species of carnivorous fish can get the same nutrients without eating other fish
China uses carp and catfish which grow in rice paddies. These fish add nutrients to the water which act as a fertilizer for the rice

23. Aquaculture - Impacts
There are some issues associated with fish farming:
Fish that are higher up the food chain (salmon, tuna) still require nutrients from fish lower on food chain leading to depletion of other species
Loss of habitat (mangroves) to create fish farms
Pollution of water due to fish feed and medications added to fish pens
Increase spread of disease due to confinement in small spaces
Often involve genetically modified species which may breed with wild fish if they escape
Escaped species may increase competition with native species

25. Collapse of Fisheries

26. Case Study: Pacific Salmon
Live along the west coast of the US (California to Alaska)
Many species endangered due to overfishing and loss of freshwater habitat (deforestation and hydroelectric dams)
Atlantic salmon farms are being established in the Pacific waters of British Columbia and Chile using net-cage aquiculture
Currently most of the salmon product being sold in the U.S. are farm-raised salmon raised in these Pacific waters.
Concerns over: escape and threat to wild Pacific salmon populations, viral and bacterial infections, parasitic sea lice, and high levels of chemicals due to fish pellets being used as food

27. Case Study: Hilsa Fish in Bangladesh
Hilsa is the national fish of Bangladesh
Anadromous like salmon – born in freshwater rivers, spend adult life in ocean (Bay of Bengal), return to rivers to spawn
National dish, part of celebrations and culture of country
Overfished due to growing population
Fishing methods non-commercial, pole and nets
Attempting to farm in ponds and among rice paddies but difficulty with fertilizing eggs
Government has banned export of fish

28. International Conflict Due to Fishing Practices
The ”cod wars” were a series of disputes between Britain and Iceland running from the 1950s to the 1970s over the rights to fish in Icelandic waters.
Turbot (halibut) war between Canada and Spain in 1995 when Canada fired on a Spanish fishing boat and chased it out of Canadian waters.
Growing tension between India and Sri Lanka in Over 100 Indian fisherman killed and 350 seriously injured because of fishing along Sri Lankan coast
This year China has increased their fishing fleet to over 2000 percent. In the past decade they have had conflict for fishing in the waters of Indonesian, the Philippines, Japanese, Korean and Russian.

29. Tragedy of the Commons
Conflict between individual need and the common good of society
If resource is seen as belonging to all, we tend to overuse and exploit
Oceans, lakes, and rivers tend to be good examples of the tragedy of the commons

30. Maximum Sustainable Yield (MSY)
Sustainable Yield: The amount of natural capital that can be extracted each year without depleting the stock to a point it is not replenishable.
Maximum Sustainable Yield (MSY): The largest yield or catch that can theoretically be taken from a species’ stock without permanently depleting the stock. (The maximum catch that will allow the population to return to carrying capacity as quickly as possible.)

31. Maximum Sustainable Yield (MSY)
Generally MSY is about ½ the carrying capacity of an organism
Carrying Capacity (K) is dependent on:
Reproductive Strategy
Lifespan of organism
Limiting factors in ecosystem (resources available)

32. Maximum Sustainable Yield (MSY)
Calculating MSY is difficult as it is hard to determine the actual carrying capacity of a population
Must look at the annual growth in a population (births and immigration) minus the annual decline in a population (death and emigration)
MSY is obtained if the population size will remain the same from one year to the next