THE RELATION BETWEEN BODY SIZE AND NUMBER OF EGGS IN THE FRESHWATER PRAWN, MACROBRACHIUM LAMARREI (H. MILNE EDWARDS) (DECAPODA, CARIDEA)

Je nach der Korpergrose trug eine weibliche Macrobrachium lamarrei 30 bis 160 Eier. Die Gesamtzahl der Eier pro Brut ist eine lineare Funktion des Gesamtvolumens des weiblichen Tieres. Als Funktion der Masseneinheit des weiblichen Tieres ausgedruckt, ist die Gesamtbiomasse der Eier pro Brut der Gesamtbiomasse des Muttertieres umgekehrt proportional. Unter Tieren gleicher Korpergrose, ist die Grose eines Eies von der Gesamtzahl der Eier in der betreffenden Brutabhangig. Je groser die Zahl der Eier in der Brut, desto kleiner ist die Grose jedes Eies., Je nach der Korpergrose trug eine weibliche Macrobrachium lamarrei 30 bis 160 Eier. Die Gesamtzahl der Eier pro Brut ist eine lineare Funktion des Gesamtvolumens des weiblichen Tieres. Als Funktion der Masseneinheit des weiblichen Tieres ausgedruckt, ist die Gesamtbiomasse der Eier pro Brut der Gesamtbiomasse des Muttertieres umgekehrt proportional. Unter Tieren gleicher Korpergrose, ist die Grose eines Eies von der Gesamtzahl der Eier in der betreffenden Brutabhangig. Je groser die Zahl der Eier in der Brut, desto kleiner ist die Grose jedes Eies.

Copper utilization during embryogenesis of Palaemon lamarrei.

The pattern of copper utilization during the embryogenesis of the freshwater prawn,Palaemon lamarrei has been described. Throughout the incubation period, lasting for 14 to 16 days, the egg ofP. lamarrei is permeable to salts and against a concentration gradient, it absorbs 11 μg of salt from the freshwater medium. Out of this total salt uptake, as much as 0.143 μg is due to the absorption of copper. Intake of copper, as a function of incubation time, exhibited a more or less similar trend to that of total salt intake and this can be attributed to the increased synthesis of haemocyani

Effects of temperature-salinity combinations on the digestion rates ofGambusia affinis

The presence of a ‘physiological stomach’ (pH 2–4) inGambusia affinis is proposed based on measurements ofpH in the gut and food intake of fish starved for 5 days, as a function of temperature and salinity of the environment. Digestion was fastest in 3‰ salinity at 30° C and slowest at 20° C in freshwater

Effects of temperature-salinity combinations on the digestion rates of Gambusia affinis

The presence of a ‘physiological stomach’ (pH 2–4) inGambusia affinis is proposed based on measurements ofpH in the gut and food intake of fish starved for 5 days, as a function of temperature and salinity of the environment. Digestion was fastest in 3‰ salinity at 30° C and slowest at 20° C in freshwater

Potential use of small water bodies of villages in Karnataka for aquaculture

Small water bodies of villages (SWBOV) are available aplenty in the state of Karnataka and have great potential for aquaculture, but absence of data on their magnitude could be a reason for their under-utilisation. An assessment of SWBOV in Karnataka was done during 2003-2005 by coining and defining a collective term for them, compiling documented information from government organisations and surveying in logically selected agro-climatic zones. SWBOV per se and water resources forming SWBOV include: open wells, rain water harvesting structures (RWHS), irrigation bore wells, gokatte, kunte, quarry ponds and irrigation canal-fed ponds. As documented information could be obtained only on the numbers of the first three, survey was conducted to derive their water spread area (WSA) and to estimate the numbers and WSA of the latter four. As the total potential and effective WSA of SWBOV are estimated to be 0.063 million ha (mha) and 0.048 mha respectively compared to 0.008 mha of brackishwater area, SWBOV could be classified as a category of inland water resource for aquaculture

Studies on the spermatogenesis of two Indian freshwater brachyurans

The events of spermatogenesis in two species of brachyuran crabs (Barytelphusa jacquemonti (Rathbun) and Oziotelphusa senex (Fabricius) were studied by light microscopy. Four different cell types were categorised in the testis, namely 1. Spermatogonia, 2. Spermatocytes, 3. Spermatids and 4. Spermatozoa. Each cell type has been studied in detail, for its structure, morphometry and the process of transformation into the next stage. Comparisons are drawn with the observations on the spermatogenesis of other decapods

Preliminary studies on the conversion of Tubifex tubifex as food by elvers of Anguilla nebulosa (Gray and Hardwicke)

Elvers of Anguilla nebulosa were reared at 23°C in confined waters and their food intake, growth and conversion efficiency (K1:%) were studied. Elvers weighing 278.33±14.35 mg were fed on an ad libitum diet of the oligochaete worm Tubifex tubifex for 60 days. On an average, the test individuals consumed 99.55±19.81 mg food/elver/day amounting to 35.76% of the initial biomass; during the corresponding period the elvers exhibited a growth rate of 5.03±2.42 mg gain in weight/elver/day which is equivalent to 5.06% of the consumed food. Thus the ‘housekeeping’ of these elvers may be regarded as established. In 50 days, the food required amounts to 0.358±50 = 17.90 times the initially stocked biomass. That is, 1 kg of initially stocked elvers may need 17.90 kg of T. tubifex to produce 0.912 kg of elver meat. A poor conversion ratio of 20 : 1 may be one reason for the slow growth of the elvers

Effects of Meal Size on Growth and Conversion Efficiency of the Freshwater Catfish Clarias batrachus (Linn.)

Effects of different daily meal size on food intake, growth and gross conversion efficiency (K,: YO) of juvenile Clarias batracbus are described. An amount of Tubifex worms equivalent to 14.2% live body weight of fish/day represents the maximum amount which a 2.75 k 0.42g C. batracbus can consume under laboratory conditions. 24,71 and 140mg/g fish/day re resent the geometrically derived maintenance, optimum and maximum feeding rates of the juvenile fis!.The SDA increased by three times from optimum to maximum levels of feeding, thus suggesting that the energy cost of converting food into body substance is more at higher levels of feeding

Histology of the male reproductive system of the prawn Macrobrachium lanchesteri (Crustacea: Decapoda)

The testis of the 'freshwater prawn Macrobrachium Ianchesteri consists of numerous branching lobules, bound by thin limiting membranes. There is very little inter-lobular space with indistinct blood sinuses and the lobules are filled with germ cells in different stages of development. The different regions of the vas deferens of the prawn viz., anterior vas deferens (AVD), mid vas deferens (MVD) and posterior vas deferens (PVO) , indicate structural variations reflecting the specific role of each region, in spenn transport, spermatophore formation and ejaculation. The nature of the glandular epithelium and presence of secretory material in the lumen suggest that packaging of sperms into a spermatophore is initiated in the AVO itself. The epithelial cells of the inner margin of the AVD and MVD are highly columnar. fonning a 'typhlosole'-like region. The histology of the MVD differs from that of the A VD in the presence of prominent circular and longitudinal muscle layers. Presence of copious secretory material in the MVD indicates further packaging of the sperms. Extensive muscle layers and reduced secretory activity are characteristic of the PVO. The male hormone-producing tissue. the androgenic gland, is situated mesially in the curvature of the ampulla, the distal end of the PVD. The histology of the gland confirms its secretory role

Observations on the fecundity of the cyprinidRasbora daniconius (Hamilton)

The present paper reports the fecundity(F) ofRasbora daniconius in relation to the total body length (L), total body weight (W) and gonad weight (G) of the fish. Catch data indicated a predominance of females during the months of July–August which is the breeding season of this species. The collected fish in the length range of 7·7–11·7 cm bore a linear relationship with their weights. The fecundity of the fish ranged from 580 to 11040 eggs fish−1. Fecundity exhibited a linear relationship withL, G andW. By subjecting the data to multiple regression analyses, a new and convenient method of best predictions ofF inR. daniconius in relation toL alone has been developed