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Environmental impact of fishing and carbon footprinting due to fishing

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Environmental impact of fishing and carbon footprinting due to fishing

  1. 1. Environmental impact of fishing and estimation of carbon foot printing due to fishing
  2. 2. Environmental impact of fishing  The environmental impact of fishing includes issues such as the availability of fish, overfishing, fisheries, and fisheries management; as well as the impact of fishing on other elements of the environment, such as by-catch. These issues are part of marine conservation, and are addressed in fisheries science programs.  There is a growing gap between the supply of fish and demand, due in part to world population growth.  Similar to other environmental issues, there can be conflict between the fishermen who depend on fishing for their income, and fishery scientists whose studies indicate that if future fish populations are to be sustainable then some fisheries must reduce or even close.
  3. 3. The journal Science published a four-year study in November 2006, which predicted that, at prevailing trends, the world would run out of wild-caught seafood in 2048. The scientists stated that the decline was a result of overfishing, pollution and other environmental factors that were reducing the population of fisheries at the same time as their ecosystems were being annihilated. Yet again the analysis has met criticism as being fundamentally flawed, and many fishery management officials, industry representatives and scientists challenge the findings, although the debate continues. Many countries, such as Tonga, the United States, Australia and Bahamas, and international management bodies have taken steps to appropriately manage marine resources Predictions…..
  4. 4. Effects on Marine habitat  Some fishing techniques also may cause habitat destruction. Blast fishing and cyanide fishing, which are illegal in many places, harm surrounding habitat.  Bottom trawling, the practice of pulling a fishing net along the sea bottom behind trawlers, removes around 5 to 25% of an area's seabed life on a single run Effect of bottom trawling on the ocean floor
  5. 5. Blast fishing Torn nets along the sea bed Cyanide fishing
  6. 6. Continue…  Several habitats are extremely vulnerable to anthropogenic disturbances that often include fishing.  Intertidal and shallow subtidal communities are diverse and resilient to small scale perturbations; they are, however, vulnerable to large scale disturbances because they cover very limited areas, are near population centres, and in most areas are intensely fished.  Reef habitats are often isolated by soft bottom habitats; they represent small islands that are heavily exploited and disturbed by people Lost trap degrading coral
  7. 7. BYCATCH  Bycatch is perhaps the most serious general environmental impact of modern fisheries.  Because the process is out of sight of the public and there are few objective studies, the data base is inadequate and attention to the problem has been limit
  8. 8. Continue…  Most of the species particularly vulnerable to bycatch such as mammals, sea birds, turtles, and sharks occur in aggregations.  ICES groups studying ecosystem effects of fishing activities have attempted to compensate for these problems, and these efforts continue (Anon., 1991b).  It is considered that all efforts to evaluate bycatch and environmental effects of heavy fishing on natural systems are too late because most sensitive species have long been impacted, leaving no concept of natural relationships or patterns.
  9. 9. Bycatch mainly includes.. Pelagic communities Most pelagic bycatch occurs with net fisheries The incidental catch of mammals, turtles and birds are of special concern because they are high profile species often protected by legislation Mammals • Net entanglements of the greatly depleted North Atlantic right whale are very serious; more than 50% of these rare whales are estimated to bear marks and scars indicating that they have encountered fishing gear (Kraus, 1990)
  10. 10. Continue… • The best known example of incidental take is that by the tuna purse seine fishery in the Pacific which is estimated to have taken over 6 million porpoise by 1987 with clear evidence that the porpoise populations were substantially reduced • The high seas drift net fishery is another high profile example of incidental take that resulted in threatened UN action before it was closed in the North Pacific. • This fishery covered several large geographical areas, had different target species, and different levels of bycatch (Alverson et al., 1994).
  11. 11. Continue…. Turtles Sea Turtles and other marine organisms that feed on or around target fishery resources frequently get caught as bycatch, are inadvertently killed or injured through contact with fishing gears Seabirds Tuna long line fishermen in the southern hemisphere are thought to take many tens of thousands of albatrosses and have been implicated in a massive annual kill of at least 44000 wandering albatross (Croxall, 1990). The actual annual take may be twice as high (Brothers, 1991).
  12. 12. Continue.. Several authors have discussed the relationship between fisheries and seabirds in the California Current and in Alaskan waters (Ainley and Hunt, 1991, Ainley and Sanger, 1979; DeGrange et al., 1993; Salzman, 1989; Springer, 1992; Takekawa et al., 1990), and there is a great deal of evidence of heavy incidental catch of seabirds as well as inferential evidence of resource competition between seabirds and fisheries. Ainley et al. (1994
  13. 13. Continue…. Benthic communities  There are many types of trawls, dredges, and traps that sit on or are dragged over the sea floor.  Bottom fishing gear is not selective and bycatch is a serious problem.  The effects on the sea bottom include impacts such as scraping and ploughing the bottom to substratum depths of 30 cm as well as causing resuspension of sediment and destruction of many bottom organisms
  14. 14. Continue…  Report that a beam trawl can remove bites at least 6cm into the bottom, and the boards of otter trawls get as deep as 15cm.  They report long lists of benthic species destroyed, and that most good areas are trawled over many times a year.  Their study area was fished at least three times per year, and their experimental three-fold trawling reduced echinoderms, polychaetes and molluscs by 10-65%.
  15. 15. Continue… Deep-sea Deep-sea habitats are subject to increasing amounts of fishing . These communities are characterized by life-history adaptations such as slow growth, extreme longevity, delayed age of maturation, and low natural adult mortality. Also they often are characterized by fragile structures that have important community roles (Levin et al., 1991). Such adaptations are characteristic of systems with low productivity and turnover; they are extremely vulnerable to human intervention such as fishing (Messieh et al., 1991; Thiel and Schriever, 1990), and there is a considerable risk attendant to any disturbance in this habitat.
  16. 16. Continue.. Coral reefs  The effects of fishing on coral reefs vary from altering the size structure of target fish to cascading effects on other reef fish species composition, biomass, and density (Sebens, 1994; Hughes, 1994)  Russ and Alcala (1989) document many direct and indirect effects of intense fishing on abundances, species richness, and distribution of other fishes as well as other benthic invertebrate species.
  17. 17. Continue…  Fishing on coral reefs has become extremely damaging to the reefs themselves. A recent international workshop of coral reef experts ranked overfishing as the most important hazard (Roberts, 1993), especially when dynamite is used to blast the reefs and stun fish.  This involves the loss of the reef structure that offers important protection from storm waves as well as protection from predators, breeding and nursery areas, etc.  Nonselective poisons also have been used to kill fishes; all have widespread community consequences (Saila et al., 1993).
  18. 18. Secondary effects of discards  ICES reports document that in some fisheries there can be very high proportions of discard from target species processed at sea.  This material is returned to the sea where crabs, fish, mammals and birds often aggregate to consume it.  This has certainly affected the natural behaviour of the scavenging species such as the fulmars in the late 1950s (Anon., 1991b).  Because only some species utilize this resource, it has a selective effect on the communities and may put other species at a competitive disadvantage.
  19. 19. Continue…  In most fisheries the vast majority of discarded organic material is from bycatch.  Large amounts of biomass is discarded; this affects marine ecosystems in the same way as does organic pollution from other  Human activities and often has many secondary effects. Northridge (1991) reviewed several studies that document benthic effects of discarded bycatch.
  20. 20. Case studies on bycatch discard effect on benthic fauna Extrapolation of the few good studies suggested that the total discard biomass approximates and often far exceeded that of the landings. For example,  Jones (1992) reviews Australian data collected by Wassenberg and Hill (1990) showing that prawn trawlers discard 3000 tons of material, mostly crustaceans and echinoderms, for each 500 tons of prawns; most of this discard sinks to the seafloor potentially to cause oxygen depletion problems.  One study in Norway (Oug et al., 1991) reported far-reaching effects on the benthic community that lasted at least 3 years.
  21. 21. Estimation of carbon foot printing due to fishing
  22. 22. The concept name of the carbon footprint originates from ecological footprint, discussion, which was developed by Rees and Wackernagel in the 1990s which estimates the number of "earths" that would theoretically be required if everyone on the planet consumed resources at the same level as the person calculating their ecological footprint. However, given that ecological footprints are a measure of failure, Anindita Mitra (CREA, Seattle) chose the more easily calculated "carbon footprint" to easily measure use of carbon, as an indicator of unsustainable energy use. Measure of carbon…
  23. 23.  In Indian marine fisheries, the enhanced fishing effort and efficiency in the last five decades has resulted in substantial increase in diesel consumption, equivalent to CO2 emission of 0.30 million tonnes (mt) in the year 1961 to 3.60 mt in 2010.  For every tonne of fish caught, the CO2 emission has increased from 0.50 to 1.02 t during the period.  Large differences in CO2 emission between craft types were observed.  In 2010, the larger mechanized boats (with inboard engine) emitted 1.18 t CO2/t of fish caught, and the smaller motorized boats (with outboard motor) 0.59 t CO2/t of fish caught.  Among the mechanized craft, the trawlers emitted more CO2 (1.43 t CO2/t of fish) than the gillnetters, bagnetters, seiners, liners and dolnetters (0.56–1.07 t CO2/t of fish).  There is scope to reduce CO2 by setting emission norms and improving fuel efficiency of marine fishing boat Indian scenario of carbon release in marine fishing sector
  24. 24. GHG calculation  In order to carry out calculations to determine the global warming potential of the product, NGA guidelines were followed.  The theory behind the calculation method details that the principle greenhouse gas generated by the combustion of fossil fuels for energy is carbon dioxide.  Hence the quantity of GHG produced is directly relatable to the carbon content of the fuel and the degree that the fuel is fully combusted.  NGA emission factors were used throughout all the calculations which can be found in the NGA publication. For the emissions generated by transport (whether it is by road, rail, marine or air) the following equation was used: Eii = 1000 Where: Eij is the emission of gas type, carbon dioxide, methane or nitrous oxide, from fuel type (CO2-e tones);
  25. 25. continue… Qi is the quantity of fuel type (kilolitres or gigajoules) combusted for transport energy purposes; ECi is the energy content factor of fuel type (gigajoules per kilolitre or per cubic metre) used for transport energy purposes; EF ijoxec is the emission factor for each gas type (which includes the effect of an oxidation factor) for fuel type (kilograms CO2-e per gigajoule) used for transport energy purposes.
  26. 26. Trawler..  In 2010, trawlers expended 35.58 million fishing hours, with catch rate of 44.4 kg/h (Table 3). Trawlers contributed 58.7% to the landings, and 71.1% to the CO2 emission by the mechanized sub-sector.  CO2 emission rate by trawlers was 63.5 t per fishing hour. In the mechanized sub-sector, the CO2 emission intensity was highest for trawlers (1.43 t CO2/t of fish caught) and considerably low for other craft types (0.56–1.07 t CO2/t of fish caught).  The average CO2 emission by the mechanized sub-sector was 1.18 t CO2/t of fish caught in 2010.  The motorized sub-sector expended 26.12 million fishing hours, with a catch rate of 27.2 kg/h (Table 3), and contributed 20.1% to the overall landings.  CO2 emission rate by the motorized sub-sector was 16.1 t per fishing hour; the sub-sector emitted 0.59 t CO2/t of fish caught 2010.
  27. 27. Issues facing fisheries.. In addition to releasing more quantities of CO2 into the atmosphere, the increasing fuel consumption over time indicates the following issues facing fisheries: (1) Increasing fuel consumption directly increases fishing cost and price of fish. • Fuel cost accounts for 50–54% of operating cost of mechanized boats , and 36–44% of operating cost of motorized boats17. • Majority of fish types, which form staple diet, is becoming unaffordable to common people due to increasing fishing cost.
  28. 28. Continue… (2) Use of more energy by contemporary fisheries shows increasing scouting time as a result of resource scarcity. • Availability of abundant fossil energy (even though it is becoming costly) would enable contemporary fisheries to continue until fish stocks collapse. (3) To sustain marine fisheries, India is implementing Marine Fishing Regulation Act. • One of the prominent instruments of the act is closure of mechanized fishing for 45 days every year, which is being followed for the last 12–25 years in different regions along the coast. • Analysing the performance of fisheries before and after implementation of seasonal ban, Vivekanandan et al.18 concluded that the ban has helped stabilizing the annual fishing hours and has provided short-term benefits to increase the catches, but has not helped improving the stock biomass. Increasing fuel consumption, as observed in the present analysis, shows that stabilization of fishing effort is offset by increasing fishing efficiency.
  29. 29. Fuel burning  It has been estimated that fossil-fuel burning by global fisheries is 42.4 mt, representing 1.2–3.5% of global oil consumption, releasing approximately 134 mt of CO2 into the atmosphere at an average of 1.7 t of CO2/t of live weight landed product3,20.  Our estimate on emission by marine fishing boats in India (3.6 mt of CO2) and fish production from marine capture fisheries (3.53 mt) shows that India contributes 2.7% and 3.9% to the global marine fisheries CO2 emission (134 mt) and fish production (90 mt) respectively.  Considering global estimate of 1.7 t CO2/t of live weight landed, India’s emission intensity (1.02 t CO2/t of fish landed) is low by about 40% per tonne of live weight landed.
  30. 30. CONCLUSION.. With the current trend for increased awareness of global warming and its effects on the environment Individuals and corporations can take a number of steps to reduce their carbon footprints and thus contribute to global climate mitigation. They can purchase carbon offsets (broadly stated, an investment in a carbon-reducing activity or technology) to compensate for part or all of their carbon footprint. If they purchase enough to offset their carbon footprint, they become effectively carbon neutral.
  31. 31. Reference.. 1. Environmental effects of marine fishing by PAUL K. DAYTON Scripps Institution of Oceanography, La Jolla. CA 92093, USA SIMON F. THRUSH National Institute of Water and Atmosphere, PO Box 11-11.5, Hamilton, New Zealand M. TUNDI AGARDY World Wildlife Fund, 1250 24th St. NW, Washington, DC 20037, USA and ROBERT J. HOFMAN Marine Mammal Commission, 182.5 Connecticut Ave. NW, Washington, DC 20009, USA 2. Carbon footprint by marine fishing boats of India E. Vivekanandan1,*, V. V. Singh2 and J. K. Kizhakudan1 Central Marine Fisheries Research Institute, Chennai 600 028, India Central Marine Fisheries Research Institute, Mumbai 400 059, India
  32. 32. 3. Estimating the Carbon Footprint Tuna Fisheries. Raymond R. Tan, Ph.D. and Alvin B. Culaba, Ph.D. 4. Continue…