Yeshwantrao Chavan Mahavidyalaya , Tuljapur , Dist.-Osmanabad-413 601 (MH), INDIA

1. YeshwantraoChavanMahavidyalaya, Tuljapur, Dist.-Osmanabad-413 601 (MH), INDIA Department of Fishery Science Dr S L Bhalkare Head and Assistant prof.

2. B.Sc. First Year Semester II Paper –Fish Ecology Topic : Marine Ecology

3. MarineEcology • Biology –finally! • Why do wecare? • Fishing • Waterquality • Diversity ofspecies • Medicines

4. OceanHabitats • Two major marineprovinces • Benthic =bottom • Pelagic = watercolumn BREAK

5. Benthic Zone • Littoral or Intertidal zone – area between high and lowtide • Sublittoral zone – from low tide to shelf break, ~continentalshelf • Bathyal zone – shelf break to 2000m • Abyssal zone – from 2000 to 6000m • Hadal zone – sea floor deeper than 6000 m, trenches

6. PelagicZone • Neritic zone – shallow water above the continentalshelf • Oceanic zone – deep water of open ocean beyond the shelfbreak

7. OceanicZones • Epipelagic – from surface to 200m, the maximum depth of light penetration • Mesopelagic – between 200 and 1000 m, nolight • Bathypelagic zone – between 1000 and 2000m • Abyssalpelagic zone – between 2000 and 6000m • Hadalpelagic zone – greater than 6000 m,trenches

8. Percentage of Marine Habitats

9. LightZones • Yet another way to classify theocean • Photiczone • light is sufficient forphotosynthesis • – to 100 (or 200m) • Dysphotic zone • light is too weak forphotosynthesis • twilightzone • < 5%sunlight • – 100 to 200m • Aphoticzone • nolight

10. Classification ofOrganisms • Kingdom • Phylum • Class • –Order • -Family • -Genus • -Species • Genus names arecapitalized • Genus and Species areitalicized • Homo sapiens

11. Major MarineKingdoms • Monera • Bacteria and blue-greenalgae • Protista • Single-celledorganisms • Fungi • Multicelled organisms, which feedon decay and are not plants oranimals • Metaphyta • Plants that are attached to the seafloor • Metazoa • All multicellularanimals

12. Monera • Bacteria • Important for decomposition, synthesis of organic compounds, and release of nutrients • Blue-greenalgae • Single cells, which lack a nucleus and convert ammonia and nitrogen into nitrates andnitrites

13. Protista • Single celled organisms with anucleus • Plants andanimals • – Foraminifera, coccoliths, diatoms, radiolaria dinoflagellates • Generate deep sea oozes – carbonates and silicates

14. Fungi • Abundant in the intertidalzone • Not as diverse as onland • Important indecomposition

15. Metaphyta • Plants that grow attached to the seafloor • Red, brown, and greenalgae • Advanced plants of salt marshes and coastal swamps • Only found in shallow areas where bottom is in the photiczone

16. Metazoa • Mollusks – clams, oysters, snails, squid • Arthropods – barnacles, crab,shrimp • Analids – polychaeteworms • Ctenophores – combjellies • Brachiopods – lampshells • Echinoderms – starfish, sea urchins, seacucumbers • Chordates – fishes, sea turtles, seals andwhales • o Whales, seals, and dolphins are mammals – warm blooded – Class Mammalia • o Sharks and fish - cold-blooded – Classes Chondrichthyes andPisces • – Sea turtles – Class Reptilia

17. Metazoa • All multicellularanimals

18. Classification byLifestyle • Plankton – animals that float and have no ability to propel themselves against thecurrent • Phytoplankton • plants • Primarly productivitythrough photosynthesis • Zooplankton • Animals • Eat thephytoplankton • Some can migratevertically • Nekton – activeswimmers • Marine fish, reptiles, mammals,birds… • Larger ones can swim againstcurrents • Distribution controlled by T andS

19. Classification byLifestyle • Benthos • Epifauna - live on thebottom • Infauna – live within the bottom sediments • Note: fauna signifies animals notplants • Plants are restricted to photiczone • Bacteria and animals survive at all depths, includingtrenches

20. Classification byLifestyle • One Problem: some animals start as planktonic or benthic or even nekton and change to nekton orbenthic

21. BasicEcology • Ecosystem • – The total environment including the biota (all living organisms) and non- living physical and chemicalaspects

22. BasicEcology • Environmental factors affecting life • Temperature • Salinity • Pressure • Nutrients • Dissolvedgasses • Currents • Light • Suspendedsediments • Substrate (bottommaterial) • Riverinflow • Tides • Waves

23. TemperatureEffects • Can control distribution, degree of activity, and reproduction of an organism • Temperature controls the rate of chemical reactions within organisms, thus their rate of growth andactivity • 10oC rise in temperature, doublesthe activity • Polar organisms grow slower, reproduce less frequently, andlive longer than tropicalorganisms • Tolerance to variation intemperature varies greatly between species and within an organism’slifespan • Temperature can indirectly control organisms by limiting their predators or restrictingpathogens

24. TemperatureEffects • more activity with higher temperature

25. Clams and GreenCrabs •

26. SalinityEffects • Can control the distribution of organisms and force them tomigrate in response tochanges • Availability of various dissolved chemicals (calcium and silicon) can limit an organism’s ability to constructshells • Epipelagic organisms are more tolerant to changes, since they are more accustomed tothem • Marine organisms’ body fluids have the same proportion of salts than sea water, but lowersalinity

27. Diffusion andOsmosis • Diffusion – physical process whereby molecules move from areas of higher concentration into areas of lowerconcentration • Osmosis – movement of water molecules through the cell membrane from where salinity is lower to where it ishigher • Can result in dehydration of surrounding water is more saline (saltier, highersalinity) • Can result in rupturing of the cellif surrounding water isfresher • Hydrostatic pressure – P=gh • Gases are compressible, but waternot

28. Osmoregulation • Control of diffusion through the cell wall and the maintenance of sufficient body fluids • Marineorganisms • Drink large amounts ofwater • Chloride cells extract and dispose of excesssalt • Freshwater organisms • Don’tdrink • Produce large amounts of diluteurine

29. Selective AdaptiveStrategies • Plants • 90% of marine plants arealgae • Most unicellular andmicroscopic • Photosynthesis • Takes CO2 and nutrients and makes organic compounds, O2, andenergy • Chlorophyll needed forphotosynthesis • More dense than water and sink, but have evolved various methods to retard sinking • Increasing surface area slows down sinking because of frictionaldrag • Small size results in a better ratio of drag to mass • Porous shells and spines increasedrag • Holdfasts – anchors that plants use to hold themselves to thebottom • Don’t bring in nutrients or water likethe roots of landplants

30. Diatoms • Thrive in cold, nutrient rich waters of polar region and inshore regions ofmid-latitudes • Plankton bloom– • rapidreproduction • Often inspring • Single cell in siliceous shell shaped like a pillbox-silicates

31. Selective AdaptiveStrategies • Zooplankton • Copepods • Small herbivores (plant eaters) that filter diatoms from thewater • Molt their outer skeleton as theygrow • About the size of a grain ofrice • Migrate verticallyseasonally • Foramifera • Single celled, microscopicorganisms • Calcium carbonate shells -Carbonates • Benthic forms outnumber thepelagic • Their shells are porous and protoplasm streams from inside the shell to engulf and digestfood

32. Copepods andForaminifera

33. Selective AdaptiveStrategies • Fishes • Morphology of fish has evolved to allow them to move through the watereasily

34. Three types ofDrag • Surface • Friction between the surface and thewater • Reduced by reducing surfacearea • Sphere offers least surfacedrag • Form • Function of volume of water which must be displaced • Increases as the cross-sectional areaincreases • Needle or pencil shape has least formdrag • Turbulent • Created around a body as it moves through a fluid • Reduced by having a blunt leading edge and a taperingend • Torpedo has least turbulentdrag

35. Speed inWater • Speed dependenton • Bodylength • Beatfrequency • number of times the tail (caudal fin) sweeps back and forth in a unit oftime • Aspect ratio of the caudalfin • AR = (caudal fin height)2/caudal finarea • Low aspectratio • Tail isbroad • Short, rapid acceleration and good maneuverability but lots ofdrag • Good for dartingmotion • High aspectratio • Tail isnarrow • Ideal for maintenance of highspeed, bad formaneuverability

36. Three Basic BodyTypes • Torpedoshape • Efficient, high speedcruising • Elongate • Rapidacceleration • Circular • Highmaneuverability

37. Intertidalbenthic Communities • Vary with the substrate (bottom material) • Rocky – firm, stable material for attachment, but preventsburrowing • Sandy – mobile and abrasive, but can be burrowedinto • Mud – provides little support, butis easy to burrowthrough • Infauna dominate in sand andmud