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20214
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Subject: Fisheries Resource Management × End date: 2021 × Start date: 2021 ×
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    ThesisItemOpen Access
    STUDIES ON BIOLOGICAL ASPECTS AND BODY COMPOSITION OF NON-CONVENTIONAL FISH, RED-TOOTHED TRIGGERFISH ODONUS NIGER (RUPPELL, 1836) ALONG MANGALURU AND MALPE COAST
    (KARNATAKA VETERINARY, ANIMAL AND FISHERIES SCIENCES UNIVERSITY, BIDAR, 2021) SUYANI NITIN KANJI; MRIDULA RAJESH
    The red-toothed triggerfish (Odonus niger Ruppell, 1836) is a demersal reef associated fish of the tropical Indo-Pacific area, found at a depth of 5-40 m. The body is blue, the fins are blue-green with blue edge, mouth is small and prominent, the caudal fin is C-shaped and well-developed dorsal fin spines to protect themselves from predators. The present study was based on the observation of 358 individuals (15.4 to 24.0 cm TL) comprising of 257 males and 101 females. The “r” value indicated that the most highly correlated body parameter in relation to TL was standard length (r = 0.91, p<0.01). Four out of eight morphometric characters were environmentally controlled, indicating a wide range of zoogeographical distribution of the species. ANCOVA showed no significant difference (p>0.05) between sexes, therefore, a common equation of LWRs was derived as: W = 0.04705 L2.56089. The Kn indicated almost identical condition for both the sexes. Analysis of gut contents specify that the fish is truly an omnivore and the diet was composed of crustacean remains (51.50%), zooplankton (19.97%), algae (17.70%), squid remains (4.93%), fish remains (3.70%), partially digested matter (2.16%) and detritus (0.24%). The overall sex-ratio of M:F was 1:0.39. Maturity stages indicated that the species spawns for a prolonged period, extending from November to March. Lm50 revealed that the males mature earlier than females. Absolute fecundity ranged from 16,464 to 1,01,962 eggs with an average of 49,467 ± 21675 eggs/female. Ova diameter ranged from 0.01 to 0.28 mm. The HSI values exceeded the GSI in all the months. The muscle composition revealed that the fish has high protein and low fat content and hence regarded as lean fish. Ash content of the species indicated high content of minerals. The present study revealed that O. niger could be a potential source of ω3 fatty acids as well as essential amino acids and micro nutrients such as potassium, phosphorus, sodium, magnesium and calcium.
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    ThesisItemOpen Access
    “STUDIES ON THE FISHERY AND BIOLOGY OF OBTUSE BARRACUDA, SPHYRAENA OBTUSATA [CUVIER, 1829] ALONG MANGALURU AND MALPE COAST”
    (KARNATAKA VETERINARY, ANIMAL AND FISHERIES SCIENCE UNIVERSITY, BIDAR, 2021) MESHRAM MONTI MADAN; MRUDULA RAJESH
    The obtuse barracuda, Sphyraena obtusata (Sphyraenidae), is a pelagic species found in the tropical oceans around the world. It is a voracious feeder, feeding on fishes, crustaceans and cephalopods. A total of 352 individuals of S. obtusata were analyzed which comprised of 162 males and 190 females. The comparison of different morphometric characters with total length showed high values of correlation (0.708-0.985). Analysis of meristic characters indicated that the number of spines on dorsal fin 1 (5), dorsal fin 2 (1), ventral fin (1) and anal fin (2) and number of rays on dorsal fin 2 (9), ventral fin (5) and caudal fin (17) and number of gill rakers (2) on first gill arch remained constant throughout the study. The length-weight relationships showed no significant difference between male and female and thus a common equation derived for pooled data was W = 0.01786 L2.6815 (r2 = 0.9658, n = 352). The value of relative condition factor (Kn) varied from 1.00097 ± 0.04509 to 1.00153 ± 0.05640. Gut content analysis revealed that 118 stomachs (33.52 %) were empty and 234 stomachs (66.48%) contained food in varied quantity. Index of relative importance (IRI) showed highest value for fishes (93.76%) followed by crustaceans (6.09 %) and cephalopods (0.15%). The reproductive biology of S. obtusata revealed that there are seven maturity stages in female and five maturity stages in male. The sex ratio skewed towards females with an overall ratio of 1:1.17 (Male: Female). The spawning season of S. obtusata was observed during September to December. The size at first maturity of male and female was found to be 21.3 and 21.1 respectively. The absolute fecundity ranged from 91,942 to 1,34,445 with an average of 1,12,878 ± 2,763. The ova diameter ranged from 0.02 to 0.48 mm. The gonadosomatic index (GSI) ranged from 1.23 ± 0.23 to 3.64 ± 0.98 for male and 1.31 ± 0.21 to 3.8 ± 0.39 for female. The proximate composition of S. obtusata showed 76.87 to 78.0 % moisture, 20.01% to 21.39% protein, 0.82% to 1.21% fat and 0.92% to 1.19% ash.
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    ThesisItemOpen Access
    ASSESSMENT OF ICHTHYOFAUNAL BIODIVERSITY OF SWARNA RIVER ESTUARY OF UDUPI DISTRICT IN KARNATAKA.
    (KARNATAKA VETERINARY, ANIMAL AND FISHERIES SCIENCES UNIVERSITY, BIDAR, 2021) HARSHATH, D.G.,; H.N.ANJANAYAPPA
    The coastal ecosystems of Karnataka are situated closer to the Western Ghats, which are considered as one of the global biodiversity hotspots. In view of this, the present study was conducted on the ichthyofaunal diversity of estuarine system of Kodi-Bengre region, which gives important insights on the abundance and seasonality of fish diversity.From August 2019 - March 2020, a total of 65 species encountered belonging to 50 genera, 37 families and 11 orders were studied. Among them, Nematalosanasus was found to be the most dominant species. Out of 10 orders, the order Perciformes stands first, comprised of 22 families represented by 36 species and the order Clupiformes ranked second with 2 families represented by 6 species. The seasonal abundance of ichthyofaunal diversity recorded during post-monsoon (Oct-Jan) is more compared to pre-monsoon (Feb- March) and monsoon (Aug-Sep). The diversity indices including Margalef's richness index (d). Shannon-wiener index (H') (at log 10), Simpson index (A) and Pielou's evenness (J) were calculated. The K- dominance curve plot showed that the diversity of species was high near the bar mouth region and at the estuarine region. These showed the closely similar diversity and proved that the number of species (richness) is more near the bar mouth region. Bray-Curtis similarity index revealed that the maximum similarity was found between pre-monsoon and monsoon seasons at S2 and S1 station. And the same pattern was also evident in the MSD plot and the stress valve, which was overlain on the MSD plot (0.13, 0.1 and 0.09), showed a good ordination of the samples collected.Biodiversity of threatened ichthyofaunal species out of the recorded 65 species, 25 species were Not Evaluated, 35 species were Least Concern, 3 species were Data Deficient, 1 species was Vulnerable, and 1 species Critically Endangered was recorded from the Swarna River estuary.
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    ThesisItemOpen Access
    TO STUDY DIFFERENT PRESERVATION TECHNIQUE IN FISH FOR ACADEMIC USE
    (KARNATAKA VETERINARY, ANIMAL AND FISHERIES SCIENCES UNIVERSITY, BIDAR, 2021) HARISHA; KUMAR NAIK
    The fishes like Clarias batrachus, Rastrelliger kanagurta, Gerres filamentosus, Nemipterus japonicus, Etroplus suratensis and Rhabdosargus sarba were preserved by using plastination technology. They were collected from fish stall centers, dissected and were fixed with 10% formal saline for 3 days. Dehydration was carried out in four changes of pure acetone for a period of 7 days depending on the size of the specimen. Impregnation was carried out by using combination of 15% tea cups and thermocol solutions prepared by recycling plastic tea cup and thermocol at room temperature for 15 days. Various fishes like Clarias batrachus – 67.70%; Rastrelliger kanagurta – 63.21%; Gerres filamentosus – 65.18%; Nemipterus japonicus – 67.86%; Etroplus suratensis – 61.83% ; and Rhabdosargus sarba - 64.97% showed over all shrinkage percentage at room temperature. The color change was black in Clarias batrachus; slightly whitish in Gerres filamentosus; and slightly yellowish in Nemipterus japonicus against their normal color. But there was no change in any morphological details except hardening. Another new innovative technique was developed for preservation of the specimens. i.e., The Elnady technique or Glycerin dry mount method. The fishes like Rastrelliger kanagurta and Gerres filamentosus were collected from fish stall centers. Elnady technique was carried out by using pure glycerin in impregnation and corn starch in curing step. Two Rastrelliger kanagurta and one Gerres filamentosus fishes were preserved. Rastrelliger kanagurta (A) – 21.00%; Rastrelliger kanagurta (B) – 20.91% and Gerres filamentosus – 8.33% showed over all shrinkage percentage at room temperature. The color was normal and consistency became soft and flexible.