1. 4.3 Aquatic Food Production Systems
Aquatic systems provide a source of food production
Unsustainable use of aquatic ecosystems can lead to environmental degradation and collapse of wild fisheries
Aquaculture provides potential for increased food production

2. Marine Ecosystem and Food Web
Photosynthesis by phytoplankton supports a highly diverse range of food webs
The highest rates of productivity are found near coastlines or in shallow seas where upwelling and nutrient enrichment of surface waters occurs

3. Upwelling When cold nutrient-rich waters come up from the ocean depths
Normally ocean productivity is low due to limiting factors (sunlight and nutrients)
Dead organisms sink to bottom

4. El Nino Southern Oscillation
Occur every few years
ENSO’s occur when the prevailing westerly winds weaken or cease and surface waters along the South and North American Coasts become warmer
Upwellings of cold nutrient rich waters are suppressed
Leads to declines in fish populations

5. Fisheries Industrial Farming and Hunting Demand is high and rising
90% in the oceans and 10% in freshwater
Includes wild fisheries and aquaculture
More than 70% of the world’s fisheries are fully exploited, in decline or too low to allow for recovery
Demand is high and rising
High in protein, low in saturated fats and contain vitamins A,B,D that humans need for healthy diet
MEDCs are becoming more health conscious

6. Methods of fishing
Developments in fishing equipment and changes to fishing methods have led to dwindling fish stocks and damage to habitats
Harvesting some species (seals and whales) can be controversial
Ethical issues arise over biorights, rights of indigenous cultures (Inuit) and international conservation legislation

7. Dredging
Dredges are large, metal-framed baskets that are dragged across the seafloor to collect shellfish like oysters, clams and scallops. In order to lift the catch into the basket, metal teeth dig into the seafloor, which can significantly impact seafloor habitat and bottom-dwelling species.

8. Gillnets
Gillnetting uses curtains of netting that are suspended by a system of floats and weights; they can be anchored to the seafloor or allowed to float at the surface. The netting is almost invisible to fish, so they swim right into it. Gill nets are often used to catch sardines, salmon and cod, but can accidentally entangle and kill other animals, including sharks and sea turtles.

9. Trawling
A bottom trawl is a type of fishing net that's pulled along the seafloor. Fishermen commonly use bottom trawls to catch shrimp and bottom-dwelling fish like halibut and sole. However, in addition to these target fish, the nets also catch a variety of ocean life that's usually thrown back dead or dying. Dragging heavy gear across the seabed can also damage sensitive seafloor habitat.

10. Longlining
Longlining employs a central fishing line that can range from one to 50 miles long; this line is strung with smaller lines of baited hooks, dangling at evenly spaced intervals. Longlines can be set near the surface to catch pelagic fish like tuna and swordfish, or laid on the seafloor to catch deep-dwelling fish like cod and halibut. Many lines, however, can hook sea turtles, sharks and seabirds that are also attracted to the bait.

11. Maximum sustainable yield
The highest amount that can be taken without permanently depleting the stock
How many fish and of what size can be taken in any year so the harvest is not impaired in subsequent years
Generally MSY is about ½ the carrying capacity of an organism (fishing quotas set below that)

12. Strategies to avoid unsustainable fishing
Unsustainable exploitation of aquatic systems can be mitigated at a variety of levels (International, national, local and individual) through policy, legislation and changes in human behavior
Improvements to boats and fishing gear
Detection of fisheries and boats via satellites
Use of quotas
Designation of marine protected areas
Restriction on types and sizes of fishing gear (including mesh size of nets)
Aquaculture has grown to provide additional food resources and support economic development and is expected to continue to rise

13. Aquaculture Advantages: Disadvantages: Loss of habitats Pollution
Accounts for over 50% of world market for fish
Takes stress off ocean fisheries
Becoming more sustainable
Efficient means of protein production
Disadvantages:
Loss of habitats
Pollution
Feed, antibiotics and other medicine added to fish pens
Spread of diseases
Escaped species (some genetically modified organisms)

14. Hatchery
Hatchery fish are bred and reared in nurseries, either for use in aquaculture or to be released and caught in wild-capture fisheries. When released in large numbers, hatchery-raised fish can compete with wild populations for food. There are also concerns about genetically weaker hatchery fish interbreeding with and threatening the viability of wild populations.

15. Open Net Pens or Cages
Open net pens or cages enclose fish such as salmon in offshore coastal areas or in freshwater lakes. Net pens are considered a high-impact aquaculture method because waste from the fish passes freely into the surrounding environment, polluting wild habitat. Farmed fish can also escape and compete with wild fish for natural resources or interbreed with wild fish of the same species, compromising the wild population. Diseases and parasites can also spread to wild fish living near or swimming past net pens.

16. Ponds
Ponds enclose fish in a coastal or inland body of fresh or salt water. Shrimp, catfish and tilapia are commonly raised in this manner. Wastewater can be contained and treated. However, the discharge of untreated wastewater from the ponds can pollute the surrounding environment and contaminate groundwater. Moreover, the construction of shrimp ponds in mangrove forests has destroyed more than 3.7 million acres of coastal habitat important to fish, birds and humans.

17. Recirculating systems
Recirculating systems raise fish in tanks in which water is treated and recycled through the system. Almost any finfish species such as striped bass, salmon and sturgeon can be raised in recirculating systems. Recirculating systems address many environmental concerns associated with fish farming—fish cannot escape, and wastewater is treated—but they are costly to operate and rely on electricity or other power sources.

18. China’s Aquaculture China produces 62% of all farmed fish worldwide
Some (carp and catfish) grown in rice paddies
Waste provides fertilizer for rice

19. International Conflict
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 Indian fisherman killed and 350 seriously injured because of fishing along Sri Lankan coast
This year China has increased their fishing fleet to over percent. In the past decade they have had conflict for fishing in the waters of Indonesian, the Philippines, Japanese, Korean and Russian.