Food and feeding habit of shellfishes

WEST BENGAL UNIVERSITY OF ANIMAL AND FISHERY SCIENCES
FACULTY OF FISHERIES SCIENCES
Sub: Food and feeding habit of shellfish.
Submitted to:
Prof. S. Behera
Dept of FRM
Submitted by:
Chhoto Kisku
Dept of FRM
FRM-509

Introduction:
Shellfish is a major component of our global
aquatic food supply. Shellfish consists broadly of 2
types of animals, crustaceans and mollusks.
Crustaceans are invertebrates with segmented
bodies, protected by hard shells made of chitin, and
include shrimp, lobster, crayfish, crab, and krill.
Mollusks are invertebrates with soft bodies, divided
into foot and visceral section.
Shellfish are not actually fish, but are simply water-
dwelling animals

Fishes are broadly divided into two
group-
1) Finfish
2) Shellfish
Common Characters of shellfish:
They have joint body structure.
Body is divisible into head, thorax and abdomen.
It has jointed appendages.
They are mainly filter feeder.
Body is covered by a mantle and shell

Shellfish classification:
Shellfish mainly two phyla, these are….
1)phylum Arthropoda.
2)phylum Mollusca.

1. Phylum Arthropoda: Common features-
Body has Three-part: head, thorax, abdomen.
Body is metamerically segmented
Three pairs of jointed legs (6 legs).
Compound eyes which contain several
thousand lenses leading to a larger field of
vision.
They possess two antenna.
In phylum arthropoda there are 5 sub phylum and
among them sub phylum crustacean is the most
important.

Crustacean:
Crustaceans form a large, diverse arthropod taxon
include crabs, lobsters, crayfish, shrimps, prawns, krill,
and barnacles. Most crustaceans are free living aquatic
animals, but some are terrestrial some are parasitic,
and some are sessile. Total 67,000 species described in
crustacean.
Based on feeding habits aquatic animals are categories
mainly three-
 Carnivorous
 Herbivorous
 Omnivorous

Fresh water crabs:
Class:Malacostraca
Order:Decapoda
Family:Potamonautidae
Genus:Platythelphusa
species: Platythelphusa armata.
Distribution :
Freshwater crabs are found throughout the tropical
and sub-tropical regions of the world. The majority
of species are endemics, occurring in only a small
geographical area.

Habitat:
Freshwater crab occurring in only a small
geographical area in fresh water region. crabs
varies very little in size. They are
primarily nocturnal, emerging to feed at night and
most of them omnivores/ predators.
Food items of crabs:
Meat, bloodworms, and tiny brined fish, vegetables,
snails etc.

Marine crabs: (Three spotted crab)
Class:Malacostraca
Order:Decapod
Family:Portunidae
Genus:Portunus
Species: Portunus sanguinolentus.
DISTRIBUTION.
A cosmopolitan species widely distributed all major
water of the world, found through Red Sea, Persian
Gulf, Mozambique, South Africa ,Madagascar,
India.

Habitats :
The crab are mainly marine habited and most
important crab are found ocean region. They like
sheltered waters such as estuaries and mangrove
areas. However, most adults live in shallow areas
below the low tide mark, where they bury
themselves in the mud during the day.
Food items:
Primarily a carnivore ,they eat almost anything.
They mainly eat slow-moving or stationary
bottom-dwelling animals such as molluscs, smaller
crabs and worms. They also eat plant material,
small fish.

PRAWN: Giant fresh water prawn
Class:Malacostraca
Order:Decapoda
Family:Palaemonidae
Genus:Macrobrachium
Species: M. rosenbergii.
Distribution:
It is found throughout the tropical and subtropical
areas of the Indo-Pacific region,
from India to Southeast Asia and Northern Australia.
The giant freshwater prawn has also been introduced
to parts of Africa, Thailand, China, Japan, New
Zealand,

Habitats:
Macrobrachium rosenbergii lives in freshwater
habitat, during its larval period, grow in brackish
water, but not as much as salt water. Once it has
grown out of its planktonic stage, it will continue to
live entirely in freshwater areas.
Food items:
Larvae are omnivorous, feeding mainly on
zooplankton. In the absence of live food they are
capable of feeding on small particles of organic
matter. Post larvae and adult M. rosenbergii are
mainly feed on algae, aquatic plants, mollusks,
oligochates, aquatic insects and other crustaceans.

Marine shrimp: ( White leg shrimp)
Class:Malacostraca
Order:Decapoda
Family:Penaeidae
Genus:Litopenaeus
Species: L. vannamei
Distribution:
White leg shrimp are native to the eastern Pacific
Ocean, from the Mexican state of Sonora to as far
south as northern Peru.

Habitat:
Mostly shrimps have been described as omnivorous
scavengers and detritus feeders. Adults live and
spawn in the open ocean, while post larvae migrate
inshore to spend their juvenile, and sub-adult stages
in coastal estuaries, lagoons or mangrove areas.
Food items:
The food items found in the examined both males
and females are Phytoplankton, Zooplankton,
Crustacean, Amphipods, Isopods, Poly chaetes,
Nematodes, Mollusca, Detritus, Mud etc.

Lobster:(Metanephrops japonicus)
Class:Malacostraca
Order:Decapoda
Family:Nephropidae
Genus:Metanephrops
Species: M. japonicus
Distriution:
Lobsters are ten-legged crustaceans closely related to
shrimp and crabs. They grow well in cold, rocky
waters off the Atlantic coast of North America. But
they found in all of the world's oceans, as well as
brackish environments and even freshwater.

Habitat:
Lobsters live in all oceans, on rocky, sandy, or
muddy bottoms from the shoreline to beyond the
edge of the continental shelf. Lobsters are
omnivores and they scavenge if necessary, and are
known to resort to cannibalism in captivity.
Food items:
Lobster typically eat live prey such as fish,
mollusks, other crustaceans, worms, and some
plant life.

2. Common Features of Phylum Mollusca:
They are bilaterally symmetrical.
Body is covered by a mantle and shell
The body is soft and unsegmented.
The circulatory system is open, with heart and aorta.
Respiration occurs through gills called ctenidia.
The ventral muscular foot helps in locomotion.
In Phylum mollusca, there are 7 total classes and
among them the most important class are
 Bivalve
 Gastropod
 cephalopod

Bivalves:
Bivalves as a group have no head and they majority
are filter feeders. The shell of a bivalve is composed
of calcium carbonate, and consists of two, usually
similar parts called valves. Class bivalvia there are 6
sub classes and their so many order and their family.
More than 15000 species are present in bivalvia.
Among the most important species are -
Clams.
Mussels.
Oyster.

Marine Clams :(giant clam)
Class:Bivalvia
Order:Cardiida
Family:Cardiidae
Genus:Tridacna
Species: Tridacna gigas
Distribution:
So many number of large clam species native to the
shallow coral reefs of the South Pacific and Indian
oceans.
 They are also found the shores of
the Philippines and in the South China Sea in the
coral reefs of Sabah.

Habitat:
Clams occupy coral reef habitats, typically within 20
meters of the surface. They are most common found
in shallow lagoons and reef flats, and are typically
embedded in sandy substrates.
Food items:
Tridacna gigas can filter particulate food, including
microscopic marine plants and animals from
seawater using its ctenidia ("gills"). However, it
obtains the bulk of its nutrition from
photosymbionts living within its tissues.

Freshwater clam: (Corbicula fluminea)
Subclass:Heterodonta
Order:Venerida
Family:Cyrenidae
Genus:Corbicula
Species: C. fluminea
Distribution:
The species has been introduced into many parts of
the world, including South America, North America
and Southeast Asia, Europe.

Habitat:
This clam originally occurs in freshwater
environments. C. fluminea requires well-oxygenated
waters and prefers fine, clean sand, clay and coarse
sand substrates.
Food items:
The clam are omnivorous in nature and they feed on
phytoplankton ,microscopic organisms, zooplankton
etc.

Freshwater pearl mussel:
Class:Bivalvia
Order:Unionida
Family:Margaritiferidae
Genus:Margaritifera
Species: M. margaritifera
Distribution:
The freshwater pearl mussel can be found on both
sides of the Atlantic, from the Arctic and temperate
regions of western Russia, through Europe to
northeastern North America.

Habitat:
Clean, fast-flowing streams and rivers are required
for the freshwater pearl mussel, where it lives buried
or partly buried in fine gravel and coarse sand,
small streams to large rivers , few species can live in
lakes.
Food items:
Freshwater mussel feed by filtering the water for
various zooplankton, detritus, and other small
plants and animals. It has been suggested that they
also use a silt and algal mix as food.

Marine mussel:(Blue mussel)
Class:Bivalvia
Order:Mytilida
Family:Mytilidae
Genus:Mytilus
Species: M. edulis
Distribution:
Native to the North Atlantic. Collectively they
occupy both coasts of the North Atlantic and of the
North Pacific in temperate to polar waters, as well
as coasts of similar nature in the Southern
Hemisphere.

Habitat:
Blue mussels are live in intertidal areas attached to
rocks and other hard substrates by strong thread-
like structures called byssal threads, secreted by
byssal glands located in the foot of the mussel.
Food items:
Mussels are filter feeders, they feed on plankton and
other microscopic sea creatures which are free-
floating in seawater. A mussel draws water in
through its incurrent siphon.

Pinctada margaritifera:(black-lip pearl oyster)
Class:Bivalvia
Order:Pteriida
Family:Pteriidae
Genus:Pinctada
Species: P. margaritifera
Distribution:
Pinctada margaritifera occupies a wide range
throughout Sudan, Australia, Indonesia, Andaman
and Nicobar Islands, the Indian Ocean, Japan and
the Pacific Ocean, Red sea.

Habitat:
P. margaritifera occur in coral reef areas. The
pearl oyster attaches itself to barnacles and other
hard substrates via a byssus. They thrive at
intertidal and sub tidal zones,
Food items:
Food sources of P. margaritifera were highly
diversified, they are filter-feeding species relying
on phytoplankton as their main source of energy.
Feed on zooplanktons, minute embryos and larval
form of various marine organisms, algal filaments,
sponge.

Class Gastropoda:
Gastropoda are a major part of the phylum
Mollusca, and are the highly diversified class in
this phylum.
Total 65,000 to 80,000 living snail and
slug species.
The class gastropod there are so many family and
among them the most important species is snail..
They found freshwater, marine water, desert area,
terrestrial area.

Pila globosa: (apple snail)
Habitat:
Pila globosa or fresh water snail is one of the largest
freshwater molluscs. It is commonly found in
freshwater ponds, pools, tanks, lakes, marshes, rice
fields and sometimes even in streams and rivers.
Food items:
The food consists of aquatic plants like Vallisneria
and Plstia which are cut by jaws and then the radula
moves forwards and backwards filing the food into
small particles exactly like the chain-saw mechanism.

Class Cephalopod:
A cephalopod is the molluscan class which
includes octopuses, squid, and cuttlefish mainly.
These exclusively marine animals are
characterized by bilateral body symmetry.
The study of cephalopods is a branch of
malacology known as teuthology.
About 800 living species of cephalopods have been
identified.
Among three species the more important species is
octopus and we are here discuss about squid.

Loligo vulgaris: (European squid)
Class:Cephalopoda
Order:Myopsida
Family:Loliginidae
Genus:Loligo
Species: L. vulgaris
Distribution:
L. vulgaris is found throughout the Mediterranean
and in the eastern Atlantic Ocean from the North
Sea to the Gulf of Guinea. In British waters, it is
mainly found in the Irish Sea, along the south coast
of England.

Habitat:
The European squid is a neritic, which undertakes
distinct horizontal and vertical migrations, depending
on the environment. European squid can be found
above various substrates, from sandy through to the
muddy bottoms.
Food items:
Squids are strictly carnivorous feeding on the
crustaceans and fish and different type of organisms
found in sea.

Shellfish allergy:
Shellfish is one of the leading causes of food allergy in
adults and child cause by common Aflatoxins,
Cyanotoxin, Gonyaulax.
Symptoms of a shellfish allergy may include:
Tingling in the mouth.
Abdominal pain, diarrhea, or vomiting.
Congestion, trouble breathing, or wheezing.
Skin reactions including itching.
Swelling of the face, lips, tongue, throat, ears, or
hands.

Importance of shellfish:
Shellfish are importance as Economically, Ecology,
Nutritional, and Environmental value..
Economical- important as ornamental value, lime
production, raw materials for poultry fish feed, pearl
production, and other jeweler items.
Ecologically shellfishes play a key role for the
balance of nature by filtering water.
Nutritionally shellfish is a store house of nutrient.
Good source of protein, lipids, vitamin, minerals etc.
Environmentally shellfishes are provide excellent
habitat for Juvenile fish and other crustaceans.

CONCLUSION:
we should know the shellfish biology. So we can easily
realize the vast importance of shellfishes. Now the
shellfish biology assists us to gain better knowledge
about these shellfishes in details so that we can use
this knowledge for our better future. So shellfish
biology helps us good management activity so that it
harvesting process should environmentally
sustainable.

References:
Handbook of fisheries and aquaculture – ICAR
Breeding and seed production of fin fish and shell
fishes – P.C.Thomas
Principles of aquaculture – T.V.R.Pillay
www.fao.org
www.google.com
www.fishbase.com

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