• Tides are the periodic variations in the surface water level of the oceans, bays, gulfs and inlets.
  • They are the result of the gravitational attraction of the sun and the moon on Earth.
  • Tides are important for a large range of animals whether it is fish or birds.
  • As the moon orbits the Earth, it's gravity sweeps across the face of our planet. It's power drags a great bulge of oceanic water in it's wake.

  • Tides occur every day of the year (every 6 hours).
  • The weakest tides of the earth are located near the equator, and the largest tides are in the Bay of Fundy in Nova Scotia.

What causes tides?

  • As the moon orbiststhe Earth it's gravity sweeps across the face of our planet. It's power drags a great bulge of oceanic water in it's wake.

Spring and Neap Tides

Spring Tides:

  • Approximately twice a month, around new moon and full moon when the sun, moon and earth form a line, the tidal force due to the sun reinforces that due to the moon, the tide's range is then at its maximun.

Neap Tides:

  • At first quarter or third quarter of the moon, when the sun and the moon are separated by 90° from the earth view, it is a Neap Tide

Lunar Tides

  • The tides occur about an hour later each day. When the moon passes overhead about an hour later each day.

three species

Sand-bubbler Crab

  • They normally live in the tropics.
  • Sand bubbler crabs are crabs of the genera Scopimera and Dotilla in the family.
  • They are small crabs that live on sandy beaches in the tropical Indo-Pacific; during the low time,they form inflated sand pellets which are destroyed by the incoming high tide.
  • It hunts meiofauna out in the sand.
  • Just a centimetre across works at breakneck speed, filtering out the meiofauna and kicking aside the waste.
  • They are really small, around 1cm across the carapase, and they are characterised by the presence of "gas windows" on the merus of the legs.


  • They swim towards the sunlight in the ocean.
  • Jellyfish are the major non-polyp form of individuals of the Phylum Cnidaria.
  • They are typified as free-swimming marine animals consisting of a gelatinous umbrella-shaped bell and trailing tentacles.
  • Most of them don't have specialized digestive, osmoregulatory, central nervous, respiratory, or circulatory systems.
  • Most jellyfish alternate between polyp and medusa generations during their life cycle.
  • Jellyfish reproduce both sexually and asexually.

  • Pulsating jellyfish and their swim pals stir up the oceans with as much vigor as tides and winds.
  • The shape of the aquatic blobs affects their mixing abilities.
  • They are carnivorous, they eat plankton, crustaceans, fish eggs, small fish and other jellyfish, ingesting and voiding through the same hole in the middle of the bell.
  • They hunt passively usind their tentacles as drift nets.
  • Other species of jellyfish are among the most common and important jellyfish predators, some of which specialize in jellies.


  • They are a group of rays, which are cartilaginous fishes related to sharks.
  • They are suborder Myliobatiodei of the order myliobatiformes, and consist of eight families.
  • Most stingrays have one or more barded stings on thir tail, which are used exclusively in self-defense. the stinger may reach a length of approximately 35 cm and it's underside has two grooves with venon glands.
  • Stingrays are usually very docile and curious, their usual reaction being to flee any disturbance, but they will sometimes brush their fins past any new object they encounter.
  • When a male is courting a female, he will follow her closely, biting at her pectoral dic. Then he places one of his two claspers into her valve.

  • Stingrays are ovoviviparous, bearing live young in "litters" of 5 to 13.
  • The female holds the embryos in the womb without a placenta. Instead, the embryos absorb nutrients from a yolk sac, and after the sac is depleted, the mother provides uterine "milk".
  • Rays have been known to store sperm and not given birth until they decide the timing is right.