[Text reading: Thurman and Trujillo: Chp 17 pp 492-516]
1) Laws and Regulations
Law of the Sea Treaty (a) established a 200 nm Exclusive Economic Zone (EEZ) from all land; (b) established a right of free passage; (c) allows exploitation of minerals in deep waters under control of United Nations; (d) provides a forum for dispute resolution.
2) Fisheries resources: Provide approximately 16% of protein consumed by humans.
a) Maximum sustainable yield MSY = the maximum fishery biomass that can be removed from the standing stock yearly and still be sustained by the fishery ecosystem.
b) Fish recruitment and survival: fewer than 1% of fish larvae survive to become breeding adults; survival depends on a complex set of interactions including food availability (competition), predation, disturbance (natural and anthropogenic).
c) World Fishery: continental shelves and upwellings provide 60% of worlds fish.
· Upwellings are very productive zones due to nutrient input. (See seasonal primary productivity maps from Humbolt current)
· Estimated potential fish mass that can be harvested is less than current harvest. Approximately 30% of the worlds fish stocks are now Overfished and another 47% are being fished at their biological limit. See Nature article by Meyers and Worm.
· Bycatch: includes any marine organisms caught incidentally by fishers seeking commercial species comprises nearly 25% of all catch; includes birds, turtles, sharks, dolphins, as well as vast numbers and biomass of invertebrates.
· Fisheries Management: Problems with focus conservation of employment for humans rather than conservation of ecosystems; with jurisdiction; with new technologies; size of fleet. Fishing effort is often greater than the worth of the catch.
d) Aquaculture is a possible means of making up shortfall from natural harvest; although there are problems with disease, eutrophication, and introduction of invasive species. Examples of animals cultured: Fish (salmon, tuna); bivalves; crustaceans (shrimp), algae.
3) Energy Resources Renewable: (i) Wind farms large turbines on tall towers could be built offshore. In Denmark 20% of the electricity needs are supplied by wind. (ii) Currents: turbines could be placed in locations of large currents e.g. Florida-Gulf Stream; though problems exist with corrosion. (iii) Waves: Currently used in Scotland LIMPET (Land Installed Marine Powered Energy Transformer). (iv) Tides: Currently used in an estuary (La Rance) in northern France. A barrier across the estruary generates 540 million kw hours annually. (v)Thermal energy: Ocean Thermal Energy Conversion possible, but needs to overcome problems with fouling and corrosion.
4) Energy Resources Non-Renewable (i) Petroleum Oil and natural gas derived from fossil plants and animals comprise 95% of economic value of marine resources. (ii) Gas Hydrates (methane hydrate) occur where pressure is high. (iii) Sand and gravel. (iv) Phosphate, metal sulfides, manganese nodules
5) Chemical resources: (i) Water - Desalination and distillation; used world wide in Caribbean and Mediterranean; e.g. Resorts world wide; (ii) Salt; (iii) Drugs marine natural products. E.g. purines extracted from harvested sponges are replicated to produce commercial antiviral compounds. Other extracts are copied to manufacture anti-malarial, anti-cancer, anti-inflammatory drugs and antibiotics.