Economic importance of mollusca

Economic importance of Mollusca

1. Economic Importance of Mollusca By Dr. Padmini bisoyi 1

2. What is Mollusca? Mollusca is the second-largest  phylum  of  invertebrate  animals after the  Arthropoda. Arthropoda 1 st Mollusca 2 nd Chordata 3 rd 2

3. Around 85,000  extant   species  of molluscs are recognized. Malacology is the branch of  invertebrate   zoology  that deals with the study of the Mollusca. 3

4. Economic importance of Mollusca On the basis of their importance to human Molluscs are grouped in to two major categories. Beneficial Molluscs Destructive Molluscs 4

5. Used as f oods Used as Bait Used as Currency/ Money Used as Ornaments Used for Dyes and Inks Used for Buttons and Pearls Used in arts Used in Medicines Found in literature Animal invention Beneficial Molluscs 5

6. Molluscs as Foods 6

7. Molluscs as Foods RED INDIANS Chitons – The main food of Red Indians. 7

8. Find ?????? Who are Red Indians ??? 8

9. Gastropods- Food of Fishes, Birds and Mammals 9

10. Land snail, Helix pomatia - New York Large Foot of Pila and Haliotis – California and South India Oyester – USA Helix pomatia Pila Oyester 10

11. Commonly used as Food: all over the world Mytilus edulis Adductor muscle of Pecten Mya arenaria Venus mercenaria 11

12. They are food for other organisms such as star fish, sponges, leeches, fish and shore birds. 12

13. Commonly used as sea food in oriental and Mediterranean countries. 13

14. Devil Fish (Octopus) Used as food in oriental and Mediterranean countries ? 14

15. Molluscs as Bait Gastropods for catching fishes. Squids are excellent baits for marine fishes such as Cod in United States. Small octopus are used as bait by line fisherman of Palk Bay ? 15

16. Molluscs as Currency / Money Red Indian tribes used Dentalium as money ( sawampum ). Value of money varies length wise. Shells of gastropods are medium of barter for Africans. ? 16

17. Molluscs as Ornaments Scaphopods, Dentalium , Tooth Shells are valued as ornaments. Nautilus shells are much used for decorations Turban shells used to colored and used as “ cat’s eye ”. Sought as curious ? 17

18. Molluscs as Dyes and Inks Murex Sp. Nucella Sp. Both of them are sources for Tyrian purple from their juices. 18

19. Find the colour … 19

20. Contents of ink-sac of cuttle fish provide a rich brown pigment called sepia, used by the artists. Normal Coloured art Sepia art There are different pre existing formats for camera still photos “ Sepia mode” is one of them. 20

21. Molluscs for Buttons and Pearls Gastropod shells are used for manufacture of buttons. Pearls are made by calms and pearl oyster (most commonly Pinctada sp. ). 21

22. Molluscs used in arts Nautilus shells are commonly used in arts. 22

23. Molluscs used in medicines The internal calcareous shells of sepia, the “Cuttle Bone” used as medicine as well as some other purposes. It is a calcium rich supplement. 23 Image from Puri Sea Beach (Cuttle Bones)

24. Molluscs found in literatures There are stories about Giant Squids and Octopus cited to play exaggerated role in popular literatures. 24 https://youtu.be/0pz3V0EI_Og

25. Animal inventions of Molluscs Cephalopods get credit for two animal inventions. Jet Propulsion Smoke Screen 25

26. 26 Recently human have been discovered the process of jet propulsion which has been used by cephalopod since millions of years.

27. A smoke screen is formed by ejecting a brownish ink into the water. This diffuses into large area and allows cephalopods to move stealthily through the smoke searching for its prey or for escape from an enemy. It is used by human in world war for escaping from enemy flights. 27

28. Destructive Molluscs Herbivores Carnivores Parasites Intermediate hosts 28 The destructive activities of some molluscs are of great importance to global economy.

29. Herbivore Molluscs Some gastropods like land slugs and snails cause damage to gardens, orchards, green houses and mushroom beds by feeding upon the succulent parts of the seedling and plant parts. They damage vegetable and flowering plants also. 29

30. The Teredo “The Ship Worm”, a type of bivalve mollusc does more harm to wooden boats and ships for which the chances of sinking of the boats and ships increases by 40%. 30

31. Carnivore Molluscs Nautica, Buccinum , Murex, Urosalpinx are bore into and feed on other molluscs . They cause serious damages to pearl and oyster industries. Urosalpinx also called oyster drill. Cephalopods are also predaceous in nature. They feed on other small molluscs , crustaceans and number of fishes. Crabs are favourite food of octopus. 31

32. Damage of oyster by Urosalpinx . It drill into the oyster and eat the inner material. 32

33. Parasitic Molluscs Members of families Pyramidellidai and Eullimidae of gastropod are ectoparasites and suck blood from bivalve molluscs , polychaetes and echinoderms. Stylifer is an endoparasite of the wall of the echinoderms. Entovalva lives in the gut of the sea cucumber and absorb digested food from host 33 Ectoparasite of Echinoderm

34. Intermediate host Molluscs Snails are served as intermediate hosts in the life cycle of Fasciola and Schistosoma . 34 Fasciola hepatica Schistosoma

35. 35 I am in Hurry Thank You So much Bye Bye

36. 36 Any Question….