SHRIMPS AND MARINE ENVIRONMENT

SHRIMPS AND MARINE ENVIRONMENT

About 85 species of shrimps are known to exist in Indian waters of which 55 species are reported either as commercially important or having considerable demand in the local as well as international market. Among these Penaeus indicus, P.monodon, P. merguiensis are having high demand and are candidate species for cultivation. The post larvae and juveniles of these species get into the estuarine waters they grow and later migrate back to sea for reproduction

They breed in the sea at different depths, Adult P.indicus are found distributed in the deep waters. They normally spawn in the depth ranging from 50-69m. Gravid .P. monodon is reported to be found in sea at a depth ranging from 50-100 m.  P. merguiensis prefer muddy bottom in a depth range of 20-40 m and shallow coastal waters for matting and spawning

Table 1
Distribution of Cultivable Shrimp
No	Species(FAO)	Common name(FAO)	Habitat	Distribution
1	P.monodon	Giant tiger prawn	Trawled over mud or sand bottom to 110 m. Juveniles occupy shallow estuarine waters, adults in deeper waters	Indo-west pacific - coast and south east Africa, India, Pakistan to Japan, the Malay Archipelago, Indonesia, New Guinea and Northern Australia.
2	P.semisulcatus	Green tiger prawn	Trawled in depths to 130 m over sandy or muddy bottom. Adults to occupy deeper waters while juvenile forms are found In shallow waters generally associated with sea grass beds.	Indo-west pacific - coast and south-cast Africa, Red sea to Japan, Korea, Malaysia and Indonesia to northern Australia. Established In the eastern Mediterranean following migration through the Suez Canal.
3	P. indicus	Indian white prawn	Seen In depth upto 90 m very muddy or sandy bottom. Post larvae and juveniles Inhabit shallow estuarine waters as part of their life cycle	Indo-west pacific - coast and south east Africa to south China through Malaysia and Indonesia to New Guinea and northern Australia.
4	P. merguiensis	Banana prawn	Seen in muddy bottom From 10 to 45 m depth. post larvae and Juveniles enter shallow estuaries.	Indo west pacific - from Persian gulf to Thailand, Hong Kong, Philippines Indonesia to New Guinea, New Caledonia and northern Australia..
5	P. japonicus	Kuruma shrimp	Inshore waters to 90 m deep over sandy mud and sandy bottom.	Indo west pacific- east coast of south Africa, Red sea, Indian seas, Korea, Japan, Taiwan, Malaysia Philippines, Indonesia New Guinea Fiji Island. By Migration through the Suez canal to the eastern Mediterranean north Australia.

Major Constituents of seawater (ppt)
Chloride	CI	18.9799	Boric acid	H3 BO3	0.0260
sulphate	SO4	-2.6486	Sodium	Na+	10.5561
Bicarbonate	HCO3	-0.1397	Magnesium	Mg++	1.2720
Bromide	Br	0.0646	Calcium	Ca++	0.4001
Fluoride	F	0.0013	potassium	Sr++	0.0133

Elements present in solution in Seawater
Element	mg/Kg(C1=19.00%)	Element	mg/Kg(C1=19.00%)
Chlorine	18980	Arsenic	0.01-0.02
Sodium	10561	Manganese	0.001-0.01
Magnesium	1272	Copper	0.001-0.01
Sulphur	884	Zinc	0.005
calcium	400	Lead	0.004
Potassium	380	Selenium	0.004
Bromine	65	Cesium	0.002
Carbon	28	Uranium	0.0015
Strontium	13	Molybdenum	0.0005
Boron	4.6	Thorium	0.0005
Silicon	0.02-4.0	Cerium	0.0004
Fluorine	1.4	Silver	0.0003
Nitrogen	0.01-0.7	Vanadium	0.0003
Aluminium	0.5	Lanthanum	0.0003
Rubidium	0.2	Yttrium	0.0003
Barium	0.05	Scandanium	0.00004
Lithium	0.1	Mercury	0.00003
Phosphorous	0.001-0.10	Gold	0.000006
Iodine	0.50	Radium	0.2*3*10^-10