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Life Cycle of Prawn
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Transcript of Life Cycle of Prawn
Life cycle of Penaeus monodon
Classification: Phylum: Arthropoda
Class: Crustacea
Order: Decapoda
Family: Penaeidae
Genus: Penaeus
Species: Penaeus monodon
Life history: Adult shrimps are bottom dwellers the offshore areas at depth of 20 to
70 meters. The life cycle starts with the spawning or release of eggs by gravid or
ripe female.
Spawning occurs at night some host after copulation in species with an
open thelyum. Eggs are released in large numbers and fall slowly to the seabed.
200000-10 lac eggs are released in one time.
Embryonic development last between 12-18 hours at temperature
between 24-28˚c and salinity range from 32-35 ‰.
After spawning the larvae hatch out 12-15 hours. There are mainly six
phases enjoyed in the life cycle. Such as:
Embryo→Larvae→Juvenile→Adolescent→Sub-adult→Adult
In the larval stage: Six phases of nauplius, three phases of protozoa,
three phases of mysis are involved. After passing larval stage, the larvae
metamorphose into the post larvae.
The young post larvae or fry move shore wards and start appearing in
the coastal waters around two weeks into their post larvae life.
The continue migrations towards mangrove and other brackish water
areas which serve as their nurseries or feeding grounds, growing to large
juveniles, post juveniles and sub-adult. At this stage, Penaeus monodon is
mainly carnivorous, feeding on slow moving microscopic animals, small crabs,
shrimps, molluscs, marine worms, detritus etc.
Although first mating occurs in the estuaries, it is only during or after
migration back to the offshore areas that full ripenering of the ovaries takes
place. First spawning occurs at 10 months of age, upon arrival in the offshore
areas, followed by 2-3 more consecutive spawning within a single season.
The adult remain in the ocean upto a ripe old age of 3,4 or 5 years
unless they die earlier of predation or diseases.
In the life cycle:
Phase Begins at Duration Mode of life Habitat
Embryo Fertilization 12 hours Planktonic Outer littoral
zone
Larvae Hatching 20 days Planktonic Outer / inner
littoral zone
Juvenile Completion of gill
system
15 days Benthic Estuary
Sub-adult Complement of
sexual
maturation first
copulation
4-5 months Benthic Outer / inner
littoral zone
Adult Completion of
sexual
maturation
10 months Benthic Outer littoral
zone (20-70 m
depth)
Coastal / estuarine / brackish water (05-25 ‰)
Oceanic waters (25-35 ‰))
Post larvae ← Post larvae ← Mysis ← Zoea
↓ ↑
Juvenile
↓ Nauplii
↑
Adolescent → Sub-adults → Adults → Egg / Embryo
Migration
Life cycle of Macrobrachium rosenbergii
Classification: Phylum: Arthropoda
Class: Crustacea
Order: Decapoda
Family: Palaemonidae
Genus: Macrobrachium
Species: Macrobrachium rosenbergii
Life history: There are four stages in the life of a fresh water prawn. Like as:
Egg→Larvae→Juvenile→Adult
From the age of 0-7 months, fast growing individuals are capable of
reproduction. A female prawn with gonad, copulate just after molting with a male
prawn leaving a hard shell.
During copulation the male deposit a gelatiness mass sparmetophore
and the under side of receive of the female, tectiscess her walking legs. The
female prawns release the egg a few hours to a few days after copulation. A fully
matured female of 50 gm can carry 50000-100000 eggs.
As the eggs are extruded from the gonophore, they are fertilized by
non-motile sperm. The fertilized eggs are then transferred to a breed chamber on
the underside of the abdominal appendage. Eggs are maturated for 21 days and
then hatch immediately after hatching the female can again release eggs. In
same case, a female can lay eggs twice a month.
The eggs of the prawn are slightly elliptical the larger eggs being 0.6-
0.7 mm in length. They are bright orange in colour.
During hatching the females drop down streams to the limits of
brackish water in estuaries and coastal marshes. Rapid movement of the female
pleopods dispenses the newly hatched larvae, which normally swim with their
heads down.
Even larvae hatch in freshwater; they will be needed survive if they are
put into brackish water within 2/3 days.
Larvae are Planktonic and develop in brackish water for 3 to 6 weeks.
After 25-30 days larvae met metamorphosis into PL.
PL can tolerate a wide range of salinity, but freshwater in their survival
habitat. And so, 2-3 weeks after metamorphosis, the PL move against the current
and so towards freshwater canals and rivers. All freshwater development takes
place in the in the river.
In the life cycle: Gonad → Copulation (hours-days) → Eggs
↓
Fertilized eggs
↓
Breeding chamber (21 days)
↓
Elliptical
↓
Adult ← Post larvae (25-30 days) ← Larvae (3-6 weeks) ← Hatch (2 / 3 days)
Life cycle of Lates calcarifer
Classification: Phylum: Chordata
Sub-phylum: Vertebrata
Class: Pisces
Sub-class: Teleostomi
Order: Percomorphi
Family: Centropomidae
Genus: Lates
Species: Lates calcarifer
Life history: Lates calcarifer (sea bass) spends most of its growing period (2-3
years) in fresh water bodies, such as rivers and lakes which are connected to the
sea.
It has a rapid growth rate, often attaining a size of 3-5 kg within 2-3
years. Adult fish (3-4 years) migrate towards the moth of the river from inland
waters into the sea where the salinity ranges between 30-32 ‰ for gonad
maturation and subsequent spawning.
The fish spawns according to the lunar cycle (usually at the on set of
the new moon or the full moon) during the late evening (1800-2000 hours)
usually in synchrony with the incoming tide.
This allows the eggs and the hatching to drift into estuaries. Here,
larval development takes place after which they migrate further upstream to
grow.
At present, it is not known whether the spent fish migrates upstream or
spends the rest of its life in the marine environment.
Smith (1965) noted that some fish spend their whole life in fresh water
environment where they grow to a length of 65 cm and 19.8 kg body weight.
Migrate downstream Egg drifting, Larval development
Migrate upstream
Figure: Migration pattern of Lates calcarifer
The gonads of such fish are usually undeveloped. In the marine
environment, sea bass attaining a length of 1.7 m have been recorded in the
Indo-Australia region.
Spawning ground
Salinity (30-32 ‰)
Nursery ground
Salinity (25-30 ‰) Coastline
Feeding ground
Brackish water / Fresh water bodies
Sub-phylum: Crustacea
Class: Copepoda Class: Cirripedia Class: Malacostraca
Ex- Copepods Ex- Barnacles
Sub-class: Stomatopoda Sub-class: Peracarida Sub-class: Eucarida
Ex- Mantis shrimp
Order: Amphipod Order: Isopoda
Ex-Grammarus Ex-Bopyrus
Order: Euphausiacea Order: Decapoda
Ex-Krill
Sub-order: Natantia (swimming) Sub-order: Reptantia (crawling)
Infra-order: Penaeidea Infra-order: Caridea
Ex- Prawns Ex- Shrimps
Infra-order: Astacura Infra-order: Palinura Infra-order: Brachyura Infra-order: Anomura
Ex- Clawed lobsters Ex- Spiny lobsters Ex- True crab Ex- Hermit crab