Introduction to Biological Oceanography Biological Oceanography (3)

© 2002 Brooks/Cole, a division of Thomson Learning, Inc. Classes of Marine Resources How are marine resources classified?  Physical resources  Biological resources  Marine energy resources  Nonextractive resources These resources can be further classified as renewable or nonrenewable.

© 2002 Brooks/Cole, a division of Thomson Learning, Inc. Salts and Minerals What salts and minerals can be obtained from the ocean?  Magnesium  Sodium chloride  Manganese nodules  Phosphorite  Metallic sulfides and muds

© 2002 Brooks/Cole, a division of Thomson Learning, Inc. Petroleum and Natural Gas Oil and gas are often found together beneath impermeable caprock. Drilling for oil offshore requires specialized equipment and is more costly than drilling on land.

© 2002 Brooks/Cole, a division of Thomson Learning, Inc. Fresh water is a valuable resource. Desalination of seawater can provide a source of fresh water. Fresh Water (above) An effective desalination method that requires little energy input.

© 2002 Brooks/Cole, a division of Thomson Learning, Inc. Marine Energy What methods of energy production could utilize the energy in the ocean? Energy generated by waves and currents Ocean thermal energy conversion

© 2002 Brooks/Cole, a division of Thomson Learning, Inc. Marine Energy A thermal energy conversion system first proposed in the 1880s.

© 2002 Brooks/Cole, a division of Thomson Learning, Inc. Biological Resources Fish, crustaceans, and mollusks are the most valuable living marine resources. Fishing employs fifteen million people worldwide.

© 2002 Brooks/Cole, a division of Thomson Learning, Inc. Biological Resources Some of the major types of commercially harvested fish, mollusks and crustaceans.

Marine finfish can be divided into the pelagic fish which live in the water column and groundfish which live on the sea floor. Most of the ocean is sparsely populated because of low nutrient availability. Area of major fish production are the coastal waters and regions of upwelling. Because they are economic to capture, major commercial fishes are those which form large schools. The fishing industry uses sonar, scouting vessels, airplanes and satellites to locate schools and then deploy the fishing fleets to those areas Living Resources

Drift nets are controversial because they capture everything too large to pass through the mesh of the net and needlessly kill many organisms. The 1989 United Nations’ Convention for the Prohibition of Long Drift Nets prohibited drift nets longer than 2.5 km, but compliance is largely voluntary and impossible to enforce on the open sea. World ocean fish production appears to have leveled at between 80 and 90 million tons annually. Currently, the expense incurred in fishing exceeds the profit from the sale of the fish and fishing industries only survive through government subsidy Living Resources

A case study of overfishing: the Great Whales

© 2002 Brooks/Cole, a division of Thomson Learning, Inc. Whaling The whaling industry has pushed most of the dozen species of great whales to the brink of extinction. (above) These five species of whales are commercially extinct.

© 2002 Brooks/Cole, a division of Thomson Learning, Inc. What are some key terms and ideas about fishery management? Maximum sustainable yield - the maximum amount of any species that can be harvested without affecting future yields Overfished - a status assigned to fish stocks that have been harvested so there is not enough breeding stock left for replenishment Commercial extinction - the depletion of a species to the point where it is no longer profitable to harvest Bycatch - animals unintentionally killed when other species are being harvested Fishery Mismanagement

Fisheries management traditionally utilizes the concept of MSY - Maximum Sustainable Yield Biological populations typically exhibit geometric growth to a point where competition and density dependent factors slow growth to a plateau The resultant growth curve of a population is a hysterisis, or ‘s’ shaped curve Point of maximum growth corresponds to rising slope. MSY models rely on the principle of only fishing the amount of biomass that the population is capable of replacing on a yearly basis Therefore, the Maximum Sustainable Yield of a population corresponds to the point of maximal growth for the population

Where do MSY models fail? 70% of all commercial fish species are fully exploited –Politics and scientific management do not mix! –MSY does not allow for ‘natural’ catastrophes –Inadequate data Many classic case-study ‘crashes’ exists –Peruvian anchovy –Pacific sardine –North Atlantic Cod New management features include –Precautionary principle –Reduced effort –Working lower down the food chain –Reducing by-catch –International cooperation

Other models (other than MSY) available to Fisheries Managers Single species management examine the effects on the target species alone - unrealistic? –Yield per recruit –Age Cohort analysis –Statistical Catch-at-Age –Virtual population analysis (VPA) Multispecies methods examine biological and technical interactions –Multispecies surplus production –Multispecies yield per recruit –Multispecies VPA –Ecosystem modeling

Mariculture is marine agriculture or fish farming of finfish, shell fish and algae. Mariculture requires raising the organisms under favorable conditions until they are large enough to be harvested for food. Currently, about one out of every four fish consumed spent part of its life in mariculture and for some organisms the percentage supplied by mariculture is even larger. For mariculture to be economically viable the species must be: –Marketable. –Inexpensive to grow. –Trophically efficient. –At marketable size within 1 to 2 years. –Disease resistant Living Resources

© 2002 Brooks/Cole, a division of Thomson Learning, Inc. Drugs Researchers estimate that 10% of marine species may contain useful medical compounds. Acyclovir, the first antiviral compound approved for humans, is derived from a Caribbean Sea sponge. Pseudopterosins, a class of anti-inflammatory drugs, is derived from marine species.

© 2002 Brooks/Cole, a division of Thomson Learning, Inc. Nonextractive Resources What are the main nonextractive resources of the ocean?  transportation  recreation

© 2002 Brooks/Cole, a division of Thomson Learning, Inc. The Law of the Sea is an international agreement that governs the use of the world ocean. The United States Exclusive Economic Zone is a 10.3 million square kilometer region of ocean on the coastal margin that the United States unilaterally claims sovereign rights to and jurisdiction of. The Law of the Sea

Several treaties regarding ownership and exploitation of the marine resources have been ratified in the last fifty years. President Truman extended U.S. control of the marine resources from the shoreline to a depth of 100 fathoms (183 m). The 1958 and 1960 Geneva Conventions on the Law of the Sea resulted in a treaty that placed the control of the sea bed, sea bed resources and water of the continental shelf under the country that owns the nearest land. The 1982 United Nations’ Draft Convention on the Law of the Sea established Territorial waters and An Exclusive Economic Zone (EEZ) that extends for 200 nautical miles offshore or to the edge of the continental shelf, if that is farther. Exclusive economic zones contain about 40% of the ocean and the high seas represent the remaining 60% Law of the Sea

© 2002 Brooks/Cole, a division of Thomson Learning, Inc. The United States Exclusive Economic Zone (EEZ) is shown in red. Other EEZs are in blue. The United States Exclusive Economic Zone