ENVM8014 Special Topics in Environmental Management: Marine Resource Management and Conservation Marine Resources Worldwide： Status and Issues Marine Resources Worldwide： Status and Issues •Marine Plants and Animals • Minerals • Communities and Ecosystems Marine Resources Worldwide Marine Mammals >120 species, 25% depleted or extinct Cetaceans : Whales, dolphins and porpoises 78 known species Baleen or toothed whole life history in water Pinnepeds : Seals, sealions and walruses true seal, eared seal must come to shore to breed, give birth and nurse the young Sirenians: Dugongs (m) and manatees (fw) 4 living species (herbivores) Whales Grey whale (Eschrichtius robustus) • one of the oldest species of mammals • travel between breeding and feeding ground yearly • up to 16 m, 36 tonnes and 50-60 years • 3 populations : Northeastern Pacific (300) Eastern Pacific (20000 - 30000) North Atlantic (extinct in 17th century) Whales Blue Whale (Balaenoptera musculus) • largest animal on earth, up to 33 m, 181 tonnes • Before whaling with harpoon gun in 1864, abundant in all oceans, largest population in Antarctic (202000 – 311000) • Whaling ban by International Whaling Commission in 1960, and by USSR in 1970, but population increase slow • In 2002 total world population estimated at 5000 – 12000 • Threats : whaling, collision with vessels, trapped with fishing gear, increase ocean noise, PCB pollution global warming – migration (thermohaline), food supply (krill location and abundance) Whales Sperm Whale (Physeter macrocephalus) • • • • • • • • Largest known toothed mammal (up to 20.5m) Largest living carnivore animal on earth Largest and heaviest brain (9 kg) Deepest diving mammal (found at depths of 2200m and hold breath for 2 hrs. Cosmopolitan, found in all oceans and the Mediterranean Sea Feed mainly on deep sea squid Total world population unknown (200,000 – 2,000,000) Brighter conservational outlook, apart from a small scale fishery in Indonesia, protected worldwide. Deep-sea squid not fished and less affected by pollution. Whales Narwhal (Monodon monoceros) (white whale) • An Arctic species of cetacean (Atlantic and Russia area of Arctic), rarely found below 70oN • Male has one long tusk (up to 3m) formed from left incisor, occasionally two tusks, female rarely has tusk • Feed mainly on cod under the ice enclosed sea but may also eat squid, shrimp, other pelagic fish or even baby seals • Mainly remain on surface but make quick deep dive • Migratory : summer near coast, winter away from shore • Predator : Polar bears and Orcas, Inuit people • World population around 50,000 Pinnepeds Japanese Sea Lion (Zalophus japonicus) • Inhabited Sea of Japan, around Japanese Archipelago and the Korean Peninsula • Harvested in early 1900s. Last colony sighted in 1950, and a juvenile captured in Hokkaido in 1974, now probably extinct. Hawaiian Monk Seal (Monachus schauinslandi) • One of the most endangered species of seals. Mediterranean Monk Seal (M. monachus) also endangered while the Carribbean Monk Seal (M. tropicalis) became extinct in 1950. Population decline due to increased human activities, ciguatoxin poisoning, high male to female ratios during breeding and entanglement by fishing net and debris Photo: NMFS Pacific Islands Fisheries Science Centre Sirenian Dugong (Dugong dugon) the only marine sirenian • • • • In waters throughout Indo-Pacific, mainly in northern Australia Dependant on seagrass Gestation 13 months, suckling period 18 – 24 months Vulnerable to extinction, Steller’s Sea Cow extinct in 1800s Sirenian Manatee (Trichachus ) • In marshy coastal areas and rivers of the Carribean Sea and Gulf of Mexico, the Amazon Basin and West Africa • Like dugong, long gestation and suckling period • Herbivore • Struck by propellar Marine Resources Worldwide：Status Other marine vertebrates Sea turtles • 7 living species (flatback, green, hawksbill, Kemp's Ridley, leatherback, loggerhead and olive ridley) • Generally worldwide found in all oceans • Sensitive to earth’s magnetic field • Sexually mature at about 30, most species return to nest at locations where they were born • 150-200 eggs/nest, incubation 2 months, hatched young spend 3-5 years in pelagic waters (floating sargassum), feeding on zooplankton and nekton • Adults are obligate herbivores in inshore seagrass beds • Endangered : poaching of eggs, harvesting adults, entangled by fishing nets, beach development and global warming (sex ratio) Green Turtle (Chelonia mydas) Photo: Douglas Shea Marine Resources Worldwide：Status Other marine vertebrates Fishes - Utilised widely as a major source of protein Fisheries – industries involved with fish, include capture fisheries and aquaculture • Information obtained from Review of the State of World Marine Fishery Resources, FAO Fisheries Technical Paper No. 457, 2005 • Monitoring of the state of marine fishery resources in the world started by FAO since early 1960 Marine Fisheries Resources Marine Fisheries Resources Total fish production • 1950 – 19.3 million tonnes • 1989 – more than 100 million tonnes • 2002 – 134.3 million tonnes Marine capture fisheries • 1950 – 16.7 million tonnes (86% of total production) • 1980 – 62 million tonnes (86% of total production) • Late 1980 – 80 million tonnes • 2000 – 86.7 million tonnes (record high) • 2002 – 84.4 million tonnes (63% of total production) Marine and inland aquaculture (2002 – 30%) Inland capture fisheries (2002 – 7%) Marine capture fisheries • In 1950 major fishing grounds :, NE Atlantic, NW Atlantic and NW Pacific • In late 1950s with development of the mechanised fishing boats, production of all fishing grounds increased, particularly SE Pacific and WC Pacific • In late 1970s to early 1980s, catches in many fishing grounds appeared to have reached a maximum, and started either levelling off or declining. • Recent few years catches in most fishing grounds levelled off, fluctuating between 77 – 86 million tonnes per year Marine capture fisheries • In late 1960s, FAO assessed the global state of the world’s marine fisheries resources (Gulland 1970,1971). • With a total world marine capture production of 60 million tonnes per year and an increasing rate of 6% per year since 1950, it was estimated that the maximum potential for all traditional exploited species was 100 million tonnes per year. • Given the difficulties in ensuring best management of each stock, the estimated practical maximum potential ceiling was 80 million tonnes per year • Therefore the levelling off of total marine capture fish production at 77- 86 million tonnes per year indicated that the maximum long-term potential of marine capture fisheries has been reached. Marine capture fisheries Catch composition Marine capture fisheries Small pelagics : herrings, sardines, anchovies Large pelagics : tunas, bonitos, billfishes, jacks, mullets sauries, mackerels, etc. Demersals : flounders, halibuts, soles, cods, hakes, haddocks, Coastal fish : Redfishes, basses, congers Crustaceans : crabs, lobsters, shrimps, prawns,krill, etc. Molluscs : abalones, conchs, oysters, mussels, scallops, clams, squids, octopus, etc.) Marine capture fisheries 1950 Small pelagics Large pelagics Demersals 1970 27% 15% 26% 2002 26% 21% 15% 29% 13% 26% Coastal fishes Crustaceans Molluscs 6% 4% 6% 6% 4% 6% 7% 7% 8% Marine capture fisheries World marine catches, main species groups by major marine fishing areas in 2002 Marine capture fisheries Northwest Pacific • Most productive fishing area • All major species group represented more or less equally • Since late 1980s catches oscillate between 20-24 million tonnes • Fluctuations caused by abundance changes of Japanese sardine (Sardinops melanostictus) and Alaska pollock (Theragra chalcogramma). Southeast Pacific • Second most productive fishing area • Catches dominated by small pelagics (mostly Peruvian anchoveta (Engraulis ringens), Chilean jack mackerel (Trachurus murphyi) and the South American sardine (Sardinops sagax) • Catch fluctuations common in connection to El Nino Marine capture fisheries Northeast Atlantic • Third most productive area • Demersal fishes most abundant followed by large pelagics and then small pelagics • catches reduction from continuous decline of Atlantic cod (Gadus morhua) since late 1960s has been balanced out by the catches increase of formerly low value species, such as blue whiting (Micromesistius poutassou) and sandeels (Ammodytes spp.). Western Central Pacific • Fourth most productive area • Catches dominated by large pelagics • Total catches increasing steadily since 1950 Marine capture fisheries Stocks of top ten species (30% of total production) Species Peruvian anchoveta Chilean jack mackerel Alaska pollock Fishing area Southeast Pacific Southeast Pacific North Pacific Exploitation State Over Over Fully Japanese anchovy Blue whiting Capelin Atlantic herring chub mackerel Skipjack tuna Largehead hairtail Northwest Pacific Northest Atlantic North Atlantic North Atlantic SE Pacific and EC Pacific Pacific and Indian Oceans NW Pacific & W Indian Ocean Fully Over Fully Fully Moderately Moderately Moderately to fully Marine capture fisheries Peruvian anchoveta (Engraulis ringens) • Planktivorous • Catches greatly reduced during El Nino events e.g.1972, 1997-98 (warm water lowered depth of thermocline, reduced upwelling, decreased phytoplankton), signs of recovery in mid 1980s & 2000 • Used exclusively for fishmeal Marine capture fisheries Chilean jack mackerel (Trachurus Murphyi) • Feeds mainly on fish larvae and small crustaceans. • Catches also affected by El Nino events, but recovery appeared to be slower (catch in 2000 only <50% of peak production in 1994). Marine capture fisheries • About 400 tons of jack mackerel (Trachurus murphyi) are caught by a Chilean purse seiner. (NOAA photo library) Marine capture fisheries Alaska pollock (Pollachius pollachius) • the largest food fish resource in the world . • >3 million tonnes per year from North Pacific • the biomass has declined in recent years, perhaps indicating problem for the Bering Sea ecosystem and the commercial fishery it supports • White fish used for fish fillet in fast food industry and premier material for surumi Marine capture fisheries Blue Whiting (Micromesistius poutassou) • A species of cod common in northeast Atlantic • abundant in the deep waters off the continental shelf (200 – 600 m), juveniles also in depth >200 m. • Adults 24 -32 cm long. • Feed on large crustaceans and small fish, important prey for a large range of predators, fish, cephalopods and marine mammals. • Fishery based on aggregations during spawning season - Marine capture fisheries Capelin (Mallotus villosus 多春魚) • • • • small pelagic shoaling fish, in Atlantic and Arctic Oceans Feeds on zooplankton in summer at edge of ice shelf Up to 20 cm (female), 25 cm (male), start spawning at age of 2 In late winter migrate inshore along arctic-subarctic coast and spawn on pebbly bottom close below tideline, all males and most females die after spawning • important food for cod (40%), marine mammals and seabirds especially when they move inshore to spawn • Catches remain low since 1990, used in fish meal and oil industry, and as food esp. roe. Marine capture fisheries Marine invertebrates White Abalone (Haliotis sorenseni) 25 – 65 m rocky reefs from California to Mexico Commercial fishery developed in 1970s but closed in 1996 listed as endangered species in 1997 Photo: John Butler, NOAA Marine Resources Worldwide：Status Minerals • Minerals of geological or biological origin occur in solution, on sea-bed surface or buried • Salt, Mg and Br recovered from seawater • Rock, coral, shells, sand, gravel and lime obtained from coastal sea bottom • Phosphorite mined from stripping salt marshes • Tin from alluvial deposits • Coal from mines under sea • Ag, Ti, Zr, Cr, rare earth minerals are extracted from shores • Petroleum (1/3 global supply from coastal realm) • Extractions produce waste (much toxic) and hazards Marine Resources Worldwide：Status Communities and Ecosystems Mangroves • Trees and shrubs adapted to living in saline coastal habitats in the tropics and subtropics (54 species in 20 genera from 16 families) Mangroves • Dominate 25% of world’s tropical coastline (total over 15.5 million ha, 6.9 in Indo-Pacific, 3.5 in Africa and 4.1 in America) • Protects coast from erosion, surge storms especially during huricanes and tsunamis • Supports unique ecosystems, especially on their intricate root systems, hosting a wide variety of organisms, including algae, barnacles, oysters, sponges, bryozoans and several commercially important species of fish and crustacea • fine, anoxic sediments under mangroves act as sinks for a variety of heavy (trace) metals and transformers of nutrients • Use as food, medicine, feul, furnitures, filters • Over half the world's mangroves have been lost in recent decade due to wood extraction, tin mining, conversion to agriculture (rice, coconut, oil palm), aquaculture and salt production, coastal industrialisation and urbanisation (especially in SE Asia and S Africa) Mangroves Avicennia marina Kandelia candel Bruguiera gymnorrhiza Communities and Ecosystems Coral reefs • Submerged aragonite structures produced by living organisms (mainly stony coral) in shallow (<50m), nutrient poor, tropical marine waters • Limited coverage (total 284300 km 2, 0.1%of ocean surface), 91.9% in Indo-Pacific and 7.6% in Atlantic and Carribean • Support high biodiversity through efficient nutrient cycling between corals, zooxanthellae, and other reef organisms • Highest primary productivity at 5-10gC/m2/day • Home to a great variety of organisms: >4000 species of fish (parrotfish, angelfish, damselfish, butterflyfish, groupers, grunts and wrasses), sponges, jellyfish, polychaetes, crustaceans, molluscs, echinoderms, sea turtles, sea snakes and visiting whales and dolphins, complex food webs Coral reefs • Estimates show that about 10% of the world’s coral reefs are dead • Threats to coral reefs : ▫ land development and pollution - removal of mangroves ▫ fish trade – aquarium fish and food fish trade, cyanide fishing, dynamite fishing & overfishing ▫ coral bleaching – global warming (high SST and irradiance result in loss of zooxanthallae ▫ ocean acidification – surface pH drops 8.25 to 8.14 coral reduced calcification ▫ Dust outbreaks – disease and death of coral associated with high dust concentrations Communities and Ecosystems Seagrass • Underwater flowering plants (grass like) in shallow, sheltered soft-bottomed marine coastlines and estuaries in all continents except Antarctica • 52 species • Highly productive and support high biomass (net production 400 gC/m2/yr), herbivory rate low, mostly stored or exported to nearby ecosystem, most productive ecosystem (store 27x1012 gC/yr, 12% of total C storage in marine ecosystems) • Provide food and shelter for numerous animals (sea turtle, dugong and manatee), nursery ground for many commercially important shrimp and fish species Seagrass • Ecological functions : ▫ improve water quality by reducing SS and absorbing dissolved nutrients ▫ stablise sediments ▫ dissipate wave energy and protect coastlines ▫ Seagrass-Coral-Mangrove interactions • ▫ ▫ ▫ Experiencing world-wide decline (2-5%/yr) (forest 0.5%) disease & extreme events (hurricanes and typhoons) excess nutrient and sediment inputs (eutrophication) mechanical damage by fishing activities, coastal engineering and boat activities ▫ climatic extremes (heat waves and hypoxic events) ▫ invasive species and excessive herbivory Communities and Ecosystems Kelp Forest • Brown macroalgae (order Laminariales) occuring in temperate and arctic waters worldwide particularly in area with hard substrate and oceanographic upwelling • Similar to land forest, comprise of different species, each occupying a story in the community with associated organisms, succession ▫ canopy kelp (largest species e.g.Macrocystis) nudibranch and skeleton shrimp ▫ stipitate kelp (few metres above sea floor e.g.Ecklonia) many fish e.g. perch, rockfish ▫ prostrate kelp (near sea floor e.g. Laminaria) brittle stars, turban snails associated with kelp holdfast ▫ benthic assemblages (other filamentous algae and sessile organisms) seastars, hydroids and benthic fishes ▫ encrusting coralline algae (cover bed rock substrate) solitary corals, various gastropods and echinoderms ▫ pelagic fishes and mammals loosely associated Kelp Forest • Very productive (fronds can grow up to 30-50cm/day), supports high plant biomass, • Support great diversity and abundance of animals especially epibenthic invertebrates (mussels and polychaetes) associated with kelp detritus • Human use : fishing of kelp associated species (lobsters and rockfish), harvest as feed for abalone and extraction of alginic acid, recreational activities (scuba diving and kayaking) • Urchin aggregations affect kelp recruitment, availability of drift kelp affects feeding behavior of sea urchins • Great reduction in recent decades (Australia 30%), due to marine pollution and water quality, kelp harvesting and overfishing, invasive species and climate changes Thank you !
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