1. Ecology of a Rocky Shore Community

2. Understanding the Influence of Tides Tides have a powerful influence on how and when we play at New England beaches. Tides have a powerful influence on how and when we play at New England beaches. –During low tide on Cape Cod Bay, it's often possible to walk 1/2 mile out onto the flats in ankle-deep water. –Six hours later, the water is suddenly too deep to stand in. – Tides cause currents that greatly affect fishing, kayaking, swimming and surfing

3. Cause and Affects of Tides The ebb and flow of tides are caused by the gravitational effect of the Sun and Moon on the Earth. The ebb and flow of tides are caused by the gravitational effect of the Sun and Moon on the Earth. Because the Moon is much closer to Earth than the Sun, its influence is much greater. Because the Moon is much closer to Earth than the Sun, its influence is much greater. When the Moon is up, it pulls water beneath it outwards into a bulge. On the opposite side of the Earth, a similar bulge is also formed by water being moved outward from the planet's rotation. When the Moon is up, it pulls water beneath it outwards into a bulge. On the opposite side of the Earth, a similar bulge is also formed by water being moved outward from the planet's rotation. These two bulges travel around the globe, producing (in most places) two high tides every day. These two bulges travel around the globe, producing (in most places) two high tides every day.

4. The water Bulge makes Tides

5. Wave Action Tides directly affect wave height Tides directly affect wave height Waves are a powerful force Waves are a powerful force Tidal currents change direction twice a day and can run at speeds of up to 5 knots around points and at harbor entrances Tidal currents change direction twice a day and can run at speeds of up to 5 knots around points and at harbor entrances

6. The Angry Sea

7. Zones of Life along a Rocky Shore

8. Rock Intertidal Zones C is the splash zone: not submerged except in storm tides C is the splash zone: not submerged except in storm tides D is the high tide zone: covered during high tide D is the high tide zone: covered during high tide A is the mid tide zone: covered much of every day A is the mid tide zone: covered much of every day B is the low tide zone: covered most of the time, only exposed during high tide. B is the low tide zone: covered most of the time, only exposed during high tide.

9. Why are some animals and plants located in special zones and not all over?

10. Adaptations for life on a high energy rocky shoreline High energy waves High energy waves Low tide exposure Low tide exposure

11. Animals on a typical New England rocky shore

12. Asian Shore Crab Asian Shore Crab (Hemigrapsus sanguineus) Periwinkle snails(Littorina littorea) Periwinkle snails(Littorina littorea) Blue Mussels(Mytilus edulis) Blue Mussels(Mytilus edulis) Purple Sea Urchin(Strongylocentrotus purpuratus ) Purple Sea Urchin(Strongylocentrotus purpuratus ) Rock Barnacles Rock Barnacles (Chthamalus fragilis) Common Sea Star(Asterias forbesi) Common Sea Star(Asterias forbesi)

13. Algae on a typical New England rocky shore Fucus (Fucus gardneri ) Fucus (Fucus gardneri ) Knotted Wrack (Ascophyllum nodosum) Knotted Wrack (Ascophyllum nodosum) Kelp (Laminaria) Kelp (Laminaria)

14. More Algae Types Ulva lobata (Sea Lettuce) Ulva lobata (Sea Lettuce) Chondrus (Chondrus chrispus) Chondrus (Chondrus chrispus)

15. Adaptations to life on a rocky shore line Adapting to Wave Shock Barnacles Barnacles Cements shell to rock Cements shell to rock Snails Snails Use a suction cup like foot Use a suction cup like foot

16. Adaptations to Wave Shock Sea Stars and Urchins Sea Stars and Urchins Tube feet with suction cup ends Tube feet with suction cup ends

17. Adaptations to Wave Shock Blue Mussels Blue Mussels Byssel Threads ( strong cables) Byssel Threads ( strong cables)

18. Adaptations to Wave Shock Crabs and Lobsters Crabs and Lobsters Wedge into rock spaces Wedge into rock spaces Hide under rocks Hide under rocks

19. Adaptations to Wave Shock Sea Weeds (macroalgae) Sea Weeds (macroalgae) Hold fasts attach to rocks Hold fasts attach to rocks

20. Rocky shore animal feeding adaptations Barnacles Barnacles Filter food with feathery legs (filter feeder) Filter food with feathery legs (filter feeder) Snails Snails Scrape food with a radula - tongue with teeth (grazers and carnivores) Scrape food with a radula - tongue with teeth (grazers and carnivores) Sea stars Sea stars Use tube feet and stomach Use tube feet and stomach

21. Reproduction adaptations Barnacles are hermaphrodites Barnacles are hermaphrodites Each barnacle has both male and female reproductive organs Each barnacle has both male and female reproductive organs

22. Sea star and Urchin Reproduction Sea stars and Urchins broad cast eggs and sperm into the water Sea stars and Urchins broad cast eggs and sperm into the water

23. Marine Snails Marine snails mate and deposit egg cases Marine snails mate and deposit egg cases

24. Marine Arthropods like crabs and lobsters mate. Female attracts male using pheromones. Female attracts male using pheromones. After the female molts and mates with the male, eggs will later be deposited on underside of her abdomen and carried until they hatch. After the female molts and mates with the male, eggs will later be deposited on underside of her abdomen and carried until they hatch.

25. Lobster with eggs Lobster with eggs Green crab with eggs Green crab with eggs

26. Off Shore In the Bay! The Harbor Seal (Phoca vitulina)

27. Eastern Atlantic Harbor Seals Live along the western coast of Europe and along the New England shoreline Live along the western coast of Europe and along the New England shoreline They like to haul out on flats that are uncovered at low tide. They like to haul out on flats that are uncovered at low tide. These seals are also seen in estuaries.(Narragansett Bay!) These seals are also seen in estuaries.(Narragansett Bay!) They spend about 80 percent of their lives in the water. They spend about 80 percent of their lives in the water.

28. Harbor Seals Appearance Have a fat body and a narrow-pinched head. The nostrils are narrow and show a typical V-shape. The eyes are quite big and close set to each other. Have a fat body and a narrow-pinched head. The nostrils are narrow and show a typical V-shape. The eyes are quite big and close set to each other. The seals' belly is always lighter than its back. The seals' belly is always lighter than its back. It is difficult to It is difficult to distinguish males from females. The seals' back usually The seals' back usually shows varied spots.

29. The Eastern Atlantic Harbor seals' fur color varies from grey to brown. The animals have black spots on their body.

30. Seal Life-cycle The females reach sexual maturity in 3 of 4 years of age. The females reach sexual maturity in 3 of 4 years of age. Males reach sexual maturity at six years of age. Males reach sexual maturity at six years of age. These seals eat a variety of fish: squid, sole, whiting, herring, shrimp, and mussels. These seals eat a variety of fish: squid, sole, whiting, herring, shrimp, and mussels.

31. Life-Cycle Unlike most other pinnipeds harbor seals are generally solitary. Unlike most other pinnipeds harbor seals are generally solitary.pinnipeds They are not highly communicative, but when feel threatened they may respond by lunging, scratching, snorting, growling or other aggressive communications. They are not highly communicative, but when feel threatened they may respond by lunging, scratching, snorting, growling or other aggressive communications. Although they are solitary they haul out in small groups for protection from predators. Although they are solitary they haul out in small groups for protection from predators. –They haul out on rocky shores, sand beaches, reefs, piers or ice, to breed, moult and rest. Moult takes place in July and August. During this time the seals' metabolism is reduced. They eat very little so conserve the energy usually expelled finding food. Moult takes place in July and August. During this time the seals' metabolism is reduced. They eat very little so conserve the energy usually expelled finding food.

32. A Male Display

33. Haul Out

34. Pups are weaned after 4 up to 6 weeks. Pups are weaned after 4 up to 6 weeks. Due to the high percentage of fat in the mother's milk (45%) the pups double their weight by the time they are weaned. Due to the high percentage of fat in the mother's milk (45%) the pups double their weight by the time they are weaned. From birth on the pups immediately can swim and dive. After 2 days the pups can remain submerged for about 2 minutes. From birth on the pups immediately can swim and dive. After 2 days the pups can remain submerged for about 2 minutes.

35. Mating During the summer time the seals come together to give birth and nurse their young. During the summer time the seals come together to give birth and nurse their young. Mating takes place right after weaning. Mating takes place right after weaning. Unlike other mammalians the ovum becomes implanted in the wall of the uterus approximately three months after breeding. Unlike other mammalians the ovum becomes implanted in the wall of the uterus approximately three months after breeding. –This makes it possible to both nurse pups and breed in the short period the seals are together. During the mating season male seals can become very aggressive. During the mating season male seals can become very aggressive. – They may fight when competing for a female. The males also display aquatic performances and vocalizations to attract a female. The males also display aquatic performances and vocalizations to attract a female.

37. Threats to the Harbor Seal Natural predators: killer whales, sharks and polar bears. Natural predators: killer whales, sharks and polar bears. They usually remain in the vicinity of their traditional breeding area year round. They usually remain in the vicinity of their traditional breeding area year round. –Due to this restricted range the viability of harbor seal populations can be at risk. the population in Lake Ontario disappeared in the early 1980's. the population in Lake Ontario disappeared in the early 1980's. In some areas (Norway, Iceland) people still hunt them In some areas (Norway, Iceland) people still hunt them In other countries (e.g. the United Kingdom) fishermen may shoot those that became entangled in fishing nets. In other countries (e.g. the United Kingdom) fishermen may shoot those that became entangled in fishing nets. Fishing nets, plastic wrapping bands and marine debris are also threats Fishing nets, plastic wrapping bands and marine debris are also threats Hunting and water pollution has drastically decreased the population of Eastern Atlantic harbor seals in the waters of The Netherlands. Hunting and water pollution has drastically decreased the population of Eastern Atlantic harbor seals in the waters of The Netherlands. –Down to less 500 in 1975, out of aprox 3000 seals. the population recovered slowly, In 1987 about 1,000 seals the population recovered slowly, In 1987 about 1,000 seals Pollutants decrease the productivity and may cause premature births. Pollutants decrease the productivity and may cause premature births. Some seals have been killed by being trapped in the intake pipes of power plants. Some seals have been killed by being trapped in the intake pipes of power plants.