Thumbnail Image

Thesis

Browse

2017 - 20182
Reset filters
Subject: Fisheries Resource Management × End date: 2019 × Start date: 2000 × Type: Thesis ×
Reset filters

Search Results

Now showing 1 - 2 of 2
  • Thumbnail Image
    ThesisItemOpen Access
    Studies on catch composition and Biology of Etroplus suratensis (Bloch, 1790) and Oreochromis niloticus (Linnaeus, 1758) from Survepalli Reservoir of Andhra Pradesh
    (SRI VENKATESWARA VETERINARY UNIVERSITY TIRUPATI - 517 502. (A.P.) INDIA, 2018-08) Prudhvi Veda Priya, P.S.; Ramalingaiah, D (MAJOR); Suguna, T; Neeraja, T
    The present investigation on Etroplus suratensis and Oreochromis niloticus describes the Morphometric and Meristic characters, Length-Weight relationship, Food and feeding habits, Reproductive biology and Age, Growth and Mortality parameters. The maximum length of Etroplus suratensis and Oreochromis niloticus were examined and found to be 23.6 cm and 42.4 cm from Sarvepalli reservoir. The observed ‘b’ values of Etroplus suratensis (Male = 2.912, Female = 3.048, Juveniles = 2.899) and for Oreochromis niloticus (Male = 3.015, Female = 3.056, Juveniles = 3.072) indicates that the growth was isometric, where the value of b can be approximated to ‘3.0’. Etroplus suratensis found to be omnivorous and feeds mainly on Filamentous algae and Oreochromis niloticus found to be herbivorous and feeds on Diatoms. The length at first maturity were observed to be 149 mm and 251 mm for E. suratensis and O. niloticus. Fecundity estimates ranged from 757 - 3715 and 1852 - 3064 for E. suratensis and O. niloticus. Age at zero length (t0) calculated as – 0.14 for E. suratensis and – 0.22 for O. niloticus. Growth parameters such as asymptotic length “L∞” and growth co-efficient “K” were estimated to be 24.8 cm and 0.43 for E. suratensis and 44.2 cm and 0.86 for O. niloticus. The total mortality (Z), natural mortality (M) and fishing mortality (F) calculated for Etroplus suratensis were 1.25, 1.0 and 0.25 and For Oreochromis niloticus were 3.21, 0.11 and 3.10 respectively.
  • Thumbnail Image
    ThesisItemOpen Access
    Studies on feeding ecology and reproductive biology of Mugil cephalus (Linnaeus, 1758) from Krishnapatnam and Mypadu coasts of Nellore District, Andhra Pradesh
    (SRI VENKATESWARA VETERINARY UNIVERSITY TIRUPATI - 517 502. (A.P.) INDIA, 2017-05) LAVANYA, D; Ramalingaiah, D (MAJOR); Suguna, T; Ravindra Kumar Reddy, D
    The flathead grey mullet, Mugil cephalus fishery supports the livelihood of the fishermen along Krishnapatnam and Mypadu coasts. In the present study, Morphometric and Meristic characteristics, Length-Weight relationship, Food and feeding, Reproductive biology, Age and Growth and Mortality parameters were studied. The maximum length of Mugil cephalus examined was found to be 32 cm and 36 cm from Krishnapatnam and Mypadu coasts respectively. The observed ‘b’ values in Krishnapatnam (male = 3.093, female = 3.023, pooled = 3.288) indicates that growth was isometric in male and female population, where the value of b can be approximated to 3. Growth in pooled population indicates the allometric growth pattern (b=3.288). In Mypadu coast, the ‘b’ values (male = 2.99, female = 3.32, pooled = 3.0944) showed that the growth is positive allometry for females and isometric growth for males and pooled population, where b value can be approximated to 3.0. Mugil cephalus found to be omnivorous, preferring mainly on Diatoms. The length at first maturity was observed to be 219.5 mm. Fecundity estimates ranged from 88,998 – 3,01,142 eggs in Kp coast and 86,568 - 3,24,148 eggs in Mypadu coast. Age at zero length (t0) calculated as - 0.4589 year and - 0.3447 year for the fishes collected from Krishnapatnam and Mypadu coasts. Growth parameters such as asymptotic length “L” and growth co-efficient “K” were estimated to be 35.839 cm and 0.7391 yr -1 from Krishnapatnam coast and 41.4891 cm and 0.54203 yr -1 from Mypadu coast. The total mortality (Z), natural mortality (M) and fishing mortality (F) calculated from Krishnapatnam coast were 1.4949, 1.3644 and 0.1305 and Mypadu coast were 2.2245, 1.0732 and 1.1512 respectively. This study indicates that fishing operations can be increased in Krishnapatnam coast. Regulation of mesh sizes for fishing gear in both the coasts will help in improving the fish to breed before being caught.