Copepod Resources In The Selected Inland Water Bodies Of Kerala and Culture Of A Species As Live Feed

Abstract- Collections for the taxonomic studies were taken from 26 stations in Kerala and 21 species have been collected and identified up to the species level. Two species are described as – Elaphoidella keralaense sp. nov. and Microcyclops indicus sp. nov. The genus Elaphoidella is reporting for the first time from Kerala. Microcyclops rubellus is reporting for first time from India. Ten species are new records from Kerala and the remaining are collected from new distributional areas. Species recorded here comes under 3 orders out of 10 orders reported so far. All species are described with full illustrations.

Seasonal variation of copepod abundance from 3 selected water bodies such as: a pond (lentic freshwater), a river (lotic freshwater) and a lake (lentic brackishwater) and its relationship with hydrographical parameters were also studied. Highest species composition was observed in pond water. In pond water, air temperature showed significant correlation with water temperature, transparency, pH and DO; water temperature with transparency, pH and DO; conducticity with transparency and silicate; pH with only silicate and Cyclopoid abundance with only DO. Its showing that copepod abundance having indirect influence with hydrographical parameters. In river water, air temperature showed significant correlation with water temperature, DO, Nitrate and calanoid copepod abundance; water temperature with cyclopoid and calanoid abundance; transparency with silicate; DO and nitrate with calanoid abundance. In lake water, air temperature showed significant correlation with water temperature, salinity, DO, silicate, nitrite, Cyclopoid and calanoid abundance; water temperature with salinity, silicate and nitrate; salinity with phosphate, and calanoid abundance; transparency with DO and nitrate; pH with nitrate and calanoid and nitrite with calanoid.

Larval cycle of Thermocyclops crassus has been carried out. There are 6 naupliar stages and 5 copepodite stages present and 6th copepodite stage is the adult. Sex can be identified from 4th copepodite stage onwards. Nine days are required by the present species to reach adult stage from egg. All stages have been fully described and illustrated. The live feed culture of copepods is considered to be an important step in biodiversity utilization. During the present investigation, the live feed culture of Thermocyclops crassus has been done in 3 investigational set ups by adding cowdung, inorganic fertilizers and a mixture of the two. A control with no fertilizers has also been set up. In the investigational set up I, 30 g of each organic, mixture of organic and inorganic and inorganic fertilizers was added and observed for 30 days. The culture experiment showed a stock establishment ranged between 1400 to 11600 copepods/litre. In the investigational set up II, half doses of the above fertilizers were added. All the three treatments were having good population density. 30 days of culture experiment showed a stock establishment ranged between 1000 to 11300 copepods/litre. In the investigational set up III, one quarter dose of the above fertilizers were added. The treatments with a mixture of organic and inorganic were found better. 30 days of culture experiment showed a stock establishment of 1600 to 11000 copepods/litre. The phytoplankton production in the control was very less compared to other treatments. The result indicated that, T. crassus possesses the qualities as a potential live feed for fishes especially ornamental fishes and other organisms including crustaceans. The thesis also contains a reference section with recent references. Thermocyclops crassus has been attempted due to the following reasons -
a) Abundant
b) Medium sized
c) Available throughout the year
d) Widely distributed
e) Comparatively lower larval period
f) Easy to manage
g) Proliferate comparatively faster