Threats to Fishery Resources

Issues Affecting Fishery Resources

• Issues in fisheries are impacting and affecting the decline of fishery resources.

Human Impact on Marine Ecosystems

• Human activities have a negative impact on marine ecosystems
• Habitat modification and loss are contributing factors, such as siltation, heat, and reclamation.
• Eutrophication, caused by nutrient enrichment, leads to algal blooms and red tides.
• Pollution from petroleum, metals, toxic chemicals, solid waste, and radioactive materials harms marine life.
• Species invasion, introduction, and translocation disrupt the natural balance.
• Greenhouse gas effect and global warming result from human activities.
• Ozone depletion has been linked to hydrocarbon gases.
• Mining, coral mining, and oil drilling cause physical damage.
• Overharvesting and illegal fishing practices, like using explosives and cyanide, contribute to declining fish populations.

Overharvesting Fish and Shellfish

• Overfishing, exceeding Maximum Sustainable Yield (MSY) and quotas, leads to fishery resource decline.
• Destructive fishing gear and methods, such as ghost traps, Moro-ami, dredges, trawlers, and small mesh sizes, cause significant damage.
• Discarding unwanted catch, like trash fish, shark fins, and marine mammals, is a wasteful practice.
• Targeting specific species disrupts food web balance.
• Fishing in one area affects migratory fish species in other areas.
• Encroachment and overcapacity exacerbate overharvesting issues.
• Fish meal and other fish-based ingredients for aquaculture feed contribute to the problem.
• The live fish trade endangers food fish and ornamental aquarium fish.

Harvesting Fish and Shellfish: Fishing Gears and Impacts

• Fishing gear include pelagic fishing, pelagic longline, gill nets, and seines nets.
• Demersal fishing gear: demersal longline, trawls, beam trawl, scallop/mussel dredges
• Set/fixed gears and traps: bottom set nets, fish wires and traps, creel and pots
• Other methods include hand gathering, dynamite, and poisons.
• Impacts of fisheries on target and non-target species, and the ecosystem
• Indirect effects are seen in food webs, physical habitat alteration, nutrient cycling, littering, ghost fishing, abundance density, size-frequency, and community level effects.
• Direct effects include death of unwanted animals (birds, sea mammals) and habitat destruction from trawling, dredging, bombing, and shore reclamation.

Aquaculture, Ranching and Impacts

• Common aquaculture activities include carp, trout, salmon, rainbow trout, tilapia, sea bass, groupers, catfish, grey mullet, shrimps, prawns, oysters, mussels, shellfish (crayfish, crabs, clams, scallops), and seaweeds.
• Impacts of aquaculture include modification to the environment, waste products, debris, interaction with wildlife, resource consumption for feeding, and pollution and contamination.
• Effluents discharge from aquaculture activities.

Exploiting Aquatic Environment for Recreation

• Recreational activities include fishing, snorkeling, boating, bait collection (lugworms for angling), shooting and ecotourism.
• Disturbance impacts include capture of more gravid fish, physical damage to soft habitats, rocky shores, coral reefs, rivers, lakes and canals.
• Permanent and behavioral disturbance to aquatic organisms occur.

Aquatic Endangered Species

• Aquatic species that are endangered include algae, sea grasses, marine mammals, turtles, fishes, mussels, and sharks and rays.
• International Union for Conservation of Nature (IUCN) provides categories on fauna and flora
• Extinct species signifies the species has died. Example Thylacine, Dodo, Passenger Pigeon, Caribbean Monk Seal
• Extinct in the wild has no free-living as natural population, but individuals survive in captivity. Example South China Tiger, Alagoas Curassow
• Critically endangered when a species faces an extremely high risk of extinction in the immediate future. Example Arakan Forest Turtle, Javan Rhino, Brazilian Merganser, Gharial
• Endangered species face a very high risk of extinction in the near future. Example Blue Whale, Giant Panda, Snow Leopard, African Wild Dog, Tiger, Albatross, Crowned Solitary Eagle, Dhole, Rangas
• Vulnerable species face a high risk of extinction in the medium-term. Example Cheetah, Gaur, Lion, Sloth Bear, Wolverine, Manatee, Polar Bear
• Conservation Dependent animals are not severely threatened, but depend on conservation programs. Example Spotted Hyena, Leopard Shark, Black Caiman
• Near Threatened can be considered threatened in the near future.
• Least Concern species face no immediate threat to survival of the species. Example: Nootka Cypress, Wood Pigeon, Harp Seal

Migratory Species

• Transboundary Shared stocks of pelagic fishes include Rastreliger spp, Decapterus, little tuna, etc in neritic waters
• Straddling species (large tunas, billfish, etc) move between two or more Exclusive Economic Zones (EEZ).
• Highly migratory species (large tunas, turtles, etc) move between two or more EEZs at greater distance.
• This leads to conflicts between states and heavy fishing.

Tuna and Turtles Migration Study

• Study of tuna and turtles migration by tagging
• Post-Nesting Migration of Leatherback Turtles from Rantau Abang, Malaysia (DoFM, 1992)

Climate Change Potential Impacts

• Climate change and greenhouse gases
• There have been big increases in greenhouse gases concentrations since pre-industrial times
• Gases include: Carbon Dioxide, Methane and Nitrous Oxide
• Global mean temperature is rising faster.
• Changes in Temperature, Sea Level and Northern Hemisphere Snow Cover Relative to 1961–1990 Averages
• Increase in global average temperature, 100-year linear trend (1906 – 2005): 0.74°C [0.56 to 0.92]
• Rate of global average sea level rise, Over 1961 – 2003: 1.8 mm per year [1.3 to 2.3]. Over 1993 – 2003: 3.1 mm per year [2.4 to 3.8]
• NH Snow Cover: Over 83-yr (1920-2003), decreasing ~2 million sq. km

Impacts of Climate Change

• The impact of sea-level rise affects humans and nature including coastal erosion and flooding.
• Increasing sea temperatures cause changes in the distribution of marine life.
• Other impacts: ocean acidification, coral bleaching, water resource disturbances, resettlement, health and disease, agriculture and aquaculture shift, and change in ecosystems.
• Coastal and Marine Resources are impacted by soil erosion of beaches, saline intrusion on lands, and increased acidification of the ocean,
• This poses risks like loss of agriculture and fisheries production, additional costs to protect coastal communities, and interruption of port operations.
• Suggested adaptations are integrated coastal zone management, regulating building development in the coastal zone. and creating a coastal buffer zone.
• Other adaptations are coastal land buyback – convert to natural reserve/corridor and building defense options.
• Climate change causes a longer growing seasons and increased biological processes.
• It can cause species shift to more tolerant of warmer, less-oxygenated waters, redeployment/relocation of coastal facilities, impact sea-level rise.
• This will impact coastal cultures because culture facilities and contaminated feeding may come from nearby waste sites.
• Changes in precipitation, freshwater flows, and lake levels and introduction of new disease organisms.
• Establishment of compensating mechanisms/interventions, longer season for production/ maintence and modifications of aquaculture systems.

Climate Change & Marine Life

• Tuna distribution will depend on normal La-Nina or El-Nino water temperatures.
• Climate Change will have a impacts on culture systems and species.
• Variables and Expected Impact on culture Systems are dependant on temperature rise and rainfull
• Culture systems include freshwater cages (Ponds, ex-mining pools, tanks), freshwater fish cages ( rivers and lakes/reservoirs), marine fish cages, shrimp ponds, rafts( mussel and seaweed), and cockle mudflats
• Climate change can impact freshwater species or mariculture species dependant on their ability to adapt.

Climate Change Adaptations

• Climate change on Cockles and Mussels and other marine life
• Climate impacts their seed production and available food source.
• Methods of adaptations include: -Ponds (fish & shrimp) – build high dikes, land-based aquaculture, develop strains specific to different environment , disease-tolerant strains.
• Other adaptations are shrimp and marine fish – need for domestication of broodstocks, hatchery - produced seeds of cockles and mussels, shift to species feeding low in trophic chain.

Coral Reefs

• Coral reefs and others are related to nursery ground and help support marine life
• Coral reefs have a global distribution across the oceans, as do mangrove areas and seagrass,
• Coral reefs occur between 30°N to 30°S of the equator not over 50 meters.
• Reefs thrive at an optimum temperature of 26–27°C, and few exist in waters below 18 °C
• In the Persian gulf, reef can tolerate at 13°C in winter and 38°C in summer
• Coral reefs are the richest biodiversity on Earth.
• Reefs protect shores from the impact of waves and storms, provide food and medicine, and economic benefits
• Coral reefs also protect sea grass meadows and mangroves.
• These reefs serve as breeding grounds/ nurseries and provide aesthetic values. Issues for coral reef, coastal development, overfishing, inland pollution, global climate change
• Global Change is threatening coral reefs because of the risk of coral bleaching.
• Rising levels of CO2 cause ocean acidification linked to human disturbances in the environment.
• Direct Human Pressures: Over-fishing effects market pressures with sedimentation coming from poor land use and deforestation.
• Coral harvesting destroys habitats with bomb and cyanide and pollution from ports, industrial sites, tourism.

Dispute Areas

• Many coastal state have a right to claim an area.
• Spratly islands between China, Philippines, Vietnam, Thailand, Malaysia, Taiwan.
• Ambalat area in the Sulawesi between Malaysia and Indonesia
• Malaysia claims the area based on a 1979 maritime chart, while Indonesia bases its claims on the 1982 Law of the Sea.
• Batu Putih is an area where Malaysia lost one island to Singapore
• Sipadan area disputed between Malaysia, Indonesia, Philippines
• Claims were settled with the International Court of Justice at the end of 2002-Malaysia

Spratly Islands

• The Spratly islands contain fishery resources, oil, gas, and EEZ.
• The island has Layang-layang, P. Mantanani, P. Ubi which are disputed between China, Vietnam, Taiwan, Malaysia, and the Phillipines.
• In 1975, Vietnam claimed presence over more than 20 islands/9 lighthouses.
• Taiwan, Malaysia, the Philippines also operate various lights in the islands
• Those lights provide navigational assertions of sovereignty,
• Malaysia- Layang-layang ("Swallow Reefs"), Mantanani, Ubin
• Layang-Layang is six hectares atoll, over 7km long and 2km wide with a reef surrounds as well as a 2000m drop around the rim
• The clear waters have visibility averaging 50-60m at Location 7.5°N, 114°E with temperatures, 21-32°C
• Various marine life inhabit: Hammerhead Shark, Manta rays, tuna, barracuda, and reef sharks as well as soft and hard corals
• Atolls are are thousands of migratory birds where a flight takes about 2 hours while 16 hour cruise hours.
• Sipadan is oceanic island that rises from a coral amount offshore.
• There are awesome 2000 foot wall dives, just 50 feet from the shore that are home for More than 3000 species of fish and hundreds of coral species
• Also turtles gather there for nesting; also known as the "Turtle Tomb" with is unique cave with tunnels chambers/skeletons
• Barracuda Point is thrill with barracuda/trevally mantas/rays in water depths where you macro life: garden eels, fish, mantis shrimps, fire
• Home for soft/hard such Dendronephyta like feather stars