Marine Fisheries Management

1. Marine Fisheries Management Original Power Point Created by Linda Rist Modified by Georgia Agricultural Education Curriculum Office June 2002

2. Ocean • can be considered the last frontier on this planet • unique physical characteristics

3. Ocean • can support wide variety of plant and animal life

4. Physical Characteristics • four major areas • zonation • salinity • temperature density • water movements

5. Zonation • classify ocean zones • depth measurements • temperature changes • pressure variations • light penetration

6. Zonation • depth and light penetration are the two most common methods • five zones

7. Zonation • supratidal • intertidal • neritic • bathyal • abyssal

8. Zonation • supratidal and intertidal • above the water level • are omitted in some classifications

9. Intertidal • sometimes called the littoral zone • area between high and low tide

10. Neritic • begins at the water line • contains more biological substance than any other part of the ocean • 10-200 miles wide

11. Neritic • 200-600 feet deep • zone stops at the end of the continental shelf • site of huge dumping of industrial and city wastes

12. Bathyal • contains the continental slope and rise • is regarded as a geologically active area • underwater avalanches and slides common

13. Abyssal • ocean deep zone • reaching depths of 5,000 meters • trenches may extend to more than 6,000 meters

14. Abyssal • trenches are referred to as the hadal zone • scarcity of food • increased water pressure • lack of dissolved oxygen

15. Abyssal • animal life must be specialized to live • must be able to obtain nutrients from rich sediments on the ocean floor

16. light penetration • euphotic zone - “twilight zone” • part of the ocean where sunlight penetrates the water • supports plant and animal life that requires sunlight to live

17. Euphotic zone • from the surface to about 600 feet beyond the horizontal shelf • below the euphotic is the cold, dark Abyssal zone

18. Salinity • concentration of salts within ocean water • concentrations and types of salts vary throughout the ocean

19. Salinity • most commonly found salt compounds consist of: • sodium - Na • chlorine - Cl • magnesium - Mg

20. Salinity • calcium - Ca • potassium - K

21. Salinity • defined as the number of grams of dissolved salt in 1,000 grams of sea water • symbol for expressing salinity is %o

22. Salinity • ranges in the ocean from 33%o to 38%o • average is about 35%o

23. Temperature Density • the ocean is a giant heat pump that moves and transports heat from the equator to the poles

24. Temperature Density • temp changes occur as you move both to a different latitude and different depths

25. Temp stratification • three layers • mixed surface layer • middle thermocline layer (10-1,000 meters) • deep water layer (1,000 - 6,000 meters)

26. Thermocline • below the light penetration depth • suggests that there is a transfer of heat vertically as well as horizontally

27. Density • mass per unit volume • dependent upon salinity • temperature • pressure

28. Density • changes result from evaporation and heating of the ocean’s surface • higher temps -lower density • density increases as the pressure and depth increase

29. Water Movements • waves • tides • currents

30. Water Movements • dictates temperature, salinity, nutrient levels as well as animal and plant life

31. Waves • classified as: • wind generated • internal • catastrophic • stationary

32. Wind generated • most common • sea • swell • surf

33. Wind generated • sea wave is an irregular wave with no systematic pattern • sea wave travels at different heights and changes direction as it moves

34. Wind generated • swell waves are uniform with similar dimensions • travel together because of their similar speed

35. Wind generated-swell • remain at a constant speed as they travel but decrease in height • sometimes travel across an entire ocean

36. Wind generated • surf wave is on occurring close to shore • water particles move in an orbital motion • toward the beach

37. Wind generated - surf • less depth • energy is directed toward the shore

38. underwater internal • found with the temperature changes in the depths of the ocean • travels more slowly but has a greater height

39. Catastrophic waves • massive power behind them • caused by storms, hurricanes and landslides on shore • commonly known catastrophic wave is the tidal wave

40. Stationary wave • occur in bays and calmer waters • does not move horizontally • water surface moves up and down

41. Tides • specialized waves caused by the gravitational attraction of the sun and moon on the earth • tides occur at very exact times with one-half lunar day

42. Tides • 12 hours 25 minutes between high tides • lunar day is longer than the solar day • tides occur 50 minutes later each day

43. Tides • an area will have either one high tide and one low tide each day (diurnal) • or two high tides an two low tides each day (semidiurnal)

44. Tides • when the sun and the moon line up with the earth a strong tide is produced • this happens every 14 days at the time of the new and full moons

45. Tides • this exceptionally high tide is called the spring tide • when the sun and moon are at right angles with each other • occurs during the half moon

46. Tides • an exceptionally low tide is produced • called neap tide

47. Currents • most common are surface currents, turbidity currents and bottom currents • surface currents, which are caused by the prevailing winds

48. Currents - surface • reach velocities of about 3 knots • 1 knot = 1.15 mph

49. Currents • when a hurricane reaches shore or an earthquake occurs, landslides can occur • landslides can produce a turbidity current underwater

50. Currents • in the deep water become the bottom currents • responsible for moving sediments on the ocean floor