1. Fisheries and Fishing Methods By K. Mannette Mason Hall Government Secondary

2. WHERE ARE WE? Trinidad and Tobago is: an archipelagic state 10 km (7miles) off the Venezuelan coast a geological extension of the South American shelf. separated by 33 km (21 miles) of sea. north of 17 South American rivers including Orinoco and Amazon Trinidad’s fishery is influenced fresh water Tobago’s fishery is more oceanic

3. GUIANA-BRAZIL CONTINENTAL SHELF

4. parrot fish Spanish hogfish grunt snapper grouper Why do we catch fish?

5. Our Fishery swim continuously in open water, offshore. Nomadic as they do not remain in one area. Pelagic - swim continuously in open water, offshore. Nomadic as they do not remain in one area. Coastal pelagics Oceanic pelagic (migratory) bottom foraging fish living near or on the seabed Demersal- bottom foraging fish living near or on the seabed Soft bottom Hard bottom Deep bottom

6. Baraccuda Common Fish Species in Tobago Wahoo Cavalli Shark Marlin Dolphinfish Flying fish Kingfish Tuna Grouper Lobster Snapper Conch

7. Fishing Methods in Trinidad and Tobago Gillnetting Fillet net (multifilament) Mono-filament net Trawling Beach Seining Trolling Palangue (drift long line) Fish potting Spear fishing A la vive (live bait) Hook and line

8. Gillnetting Monofilament Multifilament

9. Trawling

10. Beach Seining

11. Trolling Outrigger  Common in Tobago  Line with hooks are towed from outriggers

12. Longlines Demersal Pelagic

13. Fishpotting

14. Spear fishing

15. Water Safety and Pollution By K. Mannette Mason Hall Government Secondary

16. Water Safety Devices Life raft Inflatable tube Rescue can Life jacket

17. Water Safety Devices Work by making it easier to float by reducing our density Work by making it easier to float by reducing our density The safety device and your body behave as one object The safety device and your body behave as one object This safety device is bigger than your body without being heavier This safety device is bigger than your body without being heavier Volume has increased but the weight has not increased so density decreases and you float more easily Volume has increased but the weight has not increased so density decreases and you float more easily

18. Navigation Devices Accurate navigation around the ocean depends on use of: Accurate navigation around the ocean depends on use of: Satellite navigation systems in boats that send signals from boats to satellites and back Satellite navigation systems in boats that send signals from boats to satellites and back Stars as the position of Polaris (Pole Star) coincides with the direction of the Earth’s North Pole. Stars as the position of Polaris (Pole Star) coincides with the direction of the Earth’s North Pole. Magnetic compass Magnetic Compass Magnetic Compass depends on magnetism depends on magnetism compass needle always points to the Earth’s magnetic North Pole not the true North Pole compass needle always points to the Earth’s magnetic North Pole not the true North Pole The compass and the North Star are both used to find the true North Pole The compass and the North Star are both used to find the true North Pole

19. Hazards associated with scuba diving If the diver holds his breath when ascending, air expands in the lungs causing the lungs to rupture. If the diver holds his breath when ascending, air expands in the lungs causing the lungs to rupture. Decompression Sickness (Bends) Decompression Sickness (Bends) Nitrogen gas and Oxygen are pressurized in the scuba tank Nitrogen gas and Oxygen are pressurized in the scuba tank The diver breathes in the pressurized air that dissolves in the blood The diver breathes in the pressurized air that dissolves in the blood As the diver ascends, the dissolved air forms bubbles as it leaves the blood As the diver ascends, the dissolved air forms bubbles as it leaves the blood The Nitrogen bubbles accumulate in the joints of the body causing a painful condition known as Bends. The Nitrogen bubbles accumulate in the joints of the body causing a painful condition known as Bends.

20. Water Pollution It is the loss of any of the actual or potential beneficial uses of water caused by any change in its composition due to human activity. Water can look clean and clear but it can be polluted Water can look clean and clear but it can be polluted

21. Sources of Water Pollution Direct (Point) Sources Direct (Point) Sources The origin can be identified e.g factory outfalls, waste treatment plants The origin can be identified e.g factory outfalls, waste treatment plants Indirect (non-point) sources Indirect (non-point) sources Origin cannot be pinpointed Origin cannot be pinpointed Contaminants can enter water supply from soils and groundwater contaminated by human activities. Contaminants can enter water supply from soils and groundwater contaminated by human activities.

22. Types of Water Pollution Toxic pollution Toxic pollution A chemical pollutant that is not naturally occurring in aquatic ecosystems that poisons and kills organisms in and near aquatic systems A chemical pollutant that is not naturally occurring in aquatic ecosystems that poisons and kills organisms in and near aquatic systems Low levels of chemicals can accumulate along the food chain as predators consume large amounts of slightly poisoned organisms. Low levels of chemicals can accumulate along the food chain as predators consume large amounts of slightly poisoned organisms. Examples: Examples: automotive products automotive products paints and solvents paints and solvents battery acid battery acid industrial waste chemicals industrial waste chemicals toxic substances in car exhaust and solid waste incinerator smoke. toxic substances in car exhaust and solid waste incinerator smoke. Pesticides Pesticides Herbicides Herbicides Household cleaning agents Household cleaning agents Gasoline Gasoline Oil Oil

25. Sediment pollution Sediment pollution Dirt, minerals, sand, and silt eroded from the land and washed into the water from areas without enough vegetation to slow runoff. Dirt, minerals, sand, and silt eroded from the land and washed into the water from areas without enough vegetation to slow runoff. Particles suspended in water cause cloudiness Particles suspended in water cause cloudiness decreases the amount of sunlight reaching underwater plants that provide food and oxygen for aquatic animals. decreases the amount of sunlight reaching underwater plants that provide food and oxygen for aquatic animals. Particles settle into spaces between rocks, destroying the habitat of many aquatic insects and macroinvertebrates. Particles settle into spaces between rocks, destroying the habitat of many aquatic insects and macroinvertebrates. Clogs the gills of fish and aquatic organisms. Clogs the gills of fish and aquatic organisms. Buries fish and insect eggs, preventing them from hatching Buries fish and insect eggs, preventing them from hatching Types of Water Pollution

26. Soil Erosion Sedimentation Sedimentation Caused by land clearing…

27. Nutrient pollution Nutrient pollution Presence of excess nutrients (nitrogen and phosphorus) Presence of excess nutrients (nitrogen and phosphorus) Living things need nutrients, but too much damages the aquatic environment. Living things need nutrients, but too much damages the aquatic environment. Too much nutrients cause excessive plant growth (algae and vascular plants) causing water to be clouded so sunlight cannot reach plants below. Too much nutrients cause excessive plant growth (algae and vascular plants) causing water to be clouded so sunlight cannot reach plants below. When those plants die, bacteria decompose them using up dissolved oxygen that aquatic organisms need to survive (Eutrophication) When those plants die, bacteria decompose them using up dissolved oxygen that aquatic organisms need to survive (Eutrophication) Types of Water Pollution Nutrient pollutants: Nutrient pollutants: fertilizers fertilizers animal manure animal manure discharge from boat toilets discharge from boat toilets household detergents household detergents Sources of nutrient pollution: Sources of nutrient pollution: overflow from sewage treatment plants overflow from sewage treatment plants leaks from poorly maintained septic systems leaks from poorly maintained septic systems discharge from factories discharge from factories automobile exhaust automobile exhaust

28. Disposal of sewage & wastewater

29. Results in unclean coastal water Algae Coral Death of coral by algal growth

30. Thermal Pollution Thermal Pollution Water near power or industrial plant is used as coolant then returned to the environment at a higher temperature. Water near power or industrial plant is used as coolant then returned to the environment at a higher temperature. Decreases level of dissolved oxygen in water that aquatic organisms need to survive. Decreases level of dissolved oxygen in water that aquatic organisms need to survive. Types of Water Pollution

31. Bacterial pollution Bacterial pollution An excess of harmful bacteria An excess of harmful bacteria Water has beneficial bacteria but small amounts of harmful bacteria are safe. Water has beneficial bacteria but small amounts of harmful bacteria are safe. Large concentrations of bacteria can be harmful to organisms that ingest or are in contact with water. Large concentrations of bacteria can be harmful to organisms that ingest or are in contact with water. Sources of bacterial pollution: Sources of bacterial pollution: overflow from sewage treatment plants overflow from sewage treatment plants leakage from poorly maintained septic systems leakage from poorly maintained septic systems animal manure animal manure discharge from boat toilets. discharge from boat toilets. Types of Water Pollution

32. Water Pollution Causes Causes Organic matter (Nitrates, phosphates) Organic matter (Nitrates, phosphates) Fertilizers and manure from farms (plant and animal remains) Fertilizers and manure from farms (plant and animal remains) Faeces from: Faeces from: Septic tanks Septic tanks Yatchs Yatchs Wastewater treatment plants Wastewater treatment plants Chemical waste Chemical waste Oil spills, garage waste, oil leaks Oil spills, garage waste, oil leaks Pesticides at home and commercially Pesticides at home and commercially Cleaning agents from households Cleaning agents from households

33. Littering

34. results in death of coral reefs… & runoff into coastal waters

35. Beach Erosion Beach Erosion Caused by coastal development… & removal of coastal trees

36. & loss of beaches Results in beaches with steep slopes…

37. SOLUTIONS Keep or plant vegetation Build walls & silt traps

38. SOLUTIONS ACT RESPONSIBLY!

39. Water Purification Water can be cleaned and made safe for use by humans Water can be cleaned and made safe for use by humans Methods of purification Methods of purification Filtration Filtration Removal of large pieces of debris using a filter Removal of large pieces of debris using a filter Water enters a settlement tank Water enters a settlement tank Alum is added causing small particles to stick together and sink to the bottom Alum is added causing small particles to stick together and sink to the bottom

40. Water Purification Methods of purification Methods of purification Removal of dissolved materials Removal of dissolved materials Done by distillation Done by distillation Water then percolates (drips) through huge filter beds. Water then percolates (drips) through huge filter beds. Microorganisms in filter beds feed on dissolved organic matter. Microorganisms in filter beds feed on dissolved organic matter. When water reaches the bottom of the filter bed all the organic matter has been removed. When water reaches the bottom of the filter bed all the organic matter has been removed. Removal of bacteria Removal of bacteria Chemicals (chlorine or sodium hypochlorite solution) added Chemicals (chlorine or sodium hypochlorite solution) added

41. Water Purification Treatment of seawater Treatment of seawater Seawater can be treated to make drinking water by the removal of salt through: Seawater can be treated to make drinking water by the removal of salt through: Solar distillation Solar distillation Heat from the sun evaporates water in trenches covered in plastic. Heat from the sun evaporates water in trenches covered in plastic. Pure water vapour condenses on plastic, drips into gutters and is collected for drinking. Pure water vapour condenses on plastic, drips into gutters and is collected for drinking. Electrodialysis Electrodialysis An electric current draws charged particles of sodium and chloride (salt) out of the seawater across a special membrane. An electric current draws charged particles of sodium and chloride (salt) out of the seawater across a special membrane.

42. Water Purification Treatment of seawater Treatment of seawater Seawater can be treated to make drinking water by the removal of salt through: Seawater can be treated to make drinking water by the removal of salt through: Vacuum freezing Vacuum freezing Seawater frozen in a special vacuum chamber Seawater frozen in a special vacuum chamber As seawater freezes, some water ‘flash evaporates’ to steam and is pumped out leaving salt behind. As seawater freezes, some water ‘flash evaporates’ to steam and is pumped out leaving salt behind. Flash distillation Flash distillation Seawater heated under a low pressure. Seawater heated under a low pressure. Pure water vapour is condensed and drawn off as drinking water Pure water vapour is condensed and drawn off as drinking water