Notas sobre la industria de la pesca en la provincia de Buenos Aires (Excursión de setiembre a octubre de 1895).

Notas sobre las condiciones de la pesca, economía pesquera y comentarios adiciones durante la excursión realizada por Lahille durante setiembre a octubre de 1895, a localidades marítimas y cuerpos de agua dulce de la provincia de Buenos Aires.

The influence of constant temperature on the embryonic growth of Asellus aquaticus L. (Crustacea) [Translation from: Vestsi Akademii Navuk Belorusskoi SSR, Seriya Biyal. 1979(1) 128-130]

It is known that an adequately large amount of work has been devoted to investigations on the influence of temperature on the growth period of aquatic invertebrates. However, the action of the given factors on the basic biological characteristics of embryonic growth in crustaceans is virtually unknown. An experimental study of the effectiveness of the transformation of matter and energy during the period of embryogenesis in the isopod Asellus aquaticus L. under different constant temperatures was carried out. Specimens were collected in the quarry lakes of the Kurasovshchin zone (city-Minsk). The authors developed a quantitative analysis of the basic energetic properties of animals during one of the physiological stages at different constant temperatures, which allows one to determine the temperature range in which the expenditure of energy, at a given instance during embryonic growth, is minimised. For A. aquaticus this range is represented by the limits 10-22°C, during which the least expenditure of energy is observed between 14.5 and 18.8°C.

Stock-rebuilding time isopleths and constant-F stock-rebuilding plans for overfished stocks

Stock-rebuilding time isopleths relate constant levels of fishing mortality (F), stock biomass, and management goals to rebuilding times for overfished stocks. We used simulation models with uncertainty about FMSY and variability in annual intrinsic growth rates (ry) to calculate rebuilding time isopleths for Georges Bank yellowtail flounder, Limanda ferruginea, and cowcod rockfish, Sebastes levis, in the Southern California Bight. Stock-rebuilding time distributions from stochastic models were variable and right-skewed, indicating that rebuilding may take less or substantially more time than expected. The probability of long rebuilding times increased with lower biomass, higher F, uncertainty about FMSY, and autocorrelation in ry values. Uncertainty about FMSY had the greatest effect on rebuilding times. Median recovery times from simulations were insensitive to model assumptions about uncertainty and variability, suggesting that median recovery times should be considered in rebuilding plans. Isopleths calculated in previous studies by deterministic models approximate median, rather than mean, rebuilding times. Stochastic models allow managers to specify and evaluate the risk (measured as a probability) of not achieving a rebuilding goal according to schedule. Rebuilding time isopleths can be used for stocks with a range of life histories and can be based on any type of population dynamics model. They are directly applicable with constant F rebuilding plans but are also useful in other cases. We used new algorithms for simulating autocorrelated process errors from a gamma distribution and evaluated sensitivity to statistical distributions assumed for ry. Uncertainty about current biomass and fishing mortality rates can be considered with rebuilding time isopleths in evaluating and designing constant-F rebuilding plans.

Morphometry and population dynamics of Sepia aculeata, (Orbigny - 1848) along the Bombay coast

Cephalopods gained importance in the fishing industry when they emerged as one of the leading sea food products exclusively for international market in the mid seventies. Cephalopods fishery in India is still in an infant stage with vast scope for exploitation. The present work on the cephalopods fishery along the Bombay coast is an effort to quantify the resource potential of Sepia acculeata. The morphometry, growth parameters, mortality (total, natural and fishing) rates, the yield per recruit and standing stock were studied.

Morphometry and length-weight relationship of Coilia dussumieri, Valenciennes, 1848 from Mumbai waters

Coilia dussumieri Valenciennes, 1848 a component of 'dol' net fishery forms an important pelagic resource along northwest coast of India. The present communication deals with morphometry and length-weight relationship of this species along Mumbai coast. Morphometric study showed a positive correlation among the compared characters. The length-weight relationship for the species from Mumbai coast was found to be W=0.017L super(2.4223).

Morphometry, length-weight relationship and biology of Sepia aculeata (d'Orbigny, 1848) from Mumbai coast, India

Seventeen morphometric characters of Sepia aculeata of Mumbai coast have been studied and the relationships of morphometric characters with dorsal mantle length (DML) were established. The characters compared showed a fair to high degree of correlation ('r' 0.63-0.99). Number of arm suckers and shell rings were related with DML. The shell rings also showed high degree of correlation with DML ('r' 0.79-0.95). However, the relationship between arm suckers and DML was not so good ('r' 0.1-0.4). The length-weight relationship is described as W=0.1821336 L sub(2.801102). Food and feeding analysis confirm the carnivorous feeding behaviour of the species. Mature females found in all months indicate that it has prolonged spawning season with two peaks, september and march-april. Absolute fecundity ranged from 214 to 4143 eggs.

Influence of a fish bacterium Lactobacillus sp. on the production of swordtail xiphophorus helleri (Heckel 1848)

The influence of a fish gut bacterium Lactobacillus sp on the production of swordtail Xiphophorus helleri was studied for a period of one year. The Lactobacillus sp P21 produced bacteriocin-like inhibitory substance and exhibited wide spectrum of action against Aeromonas hydrophila, Bacillus spp, Pseudomonas spp and Citrobacter freundi in vitro. The growth performance of X. helleri reared in the presence of Lactobacillus P21 at 106/ml rearing water was better than the control. The total plate counts, total MRS agar counts and the counts of motile aeromonads, presumptive pseudomonads, lactose fermenters and lactose non-fermenters in the gut of probiotic group were comparatively low than the control. On day 60 the count of Lactobacillus sp P21 was observed to be log 5.28/g in the gut of X. helleri indicating colonization of this bacterium in the gastrointestinal tract. The fecundity of X. helleri was in the range of 9-134. On average, it produced from 39.42±18.72 fry/female in control group to 53.00±23.57 fry/female in probiotic group. The increase in average fecundity in probiotic group over the control group was about 25%. There existed significant difference between probiotic group and control in respect of average fecundity/female (p<0.02), average number of fry survived /female (p<0.006) and average number of fry dead/female (p<0.029). The results of the present study demonstrated that the rearing of X. helleri in probiotic-enriched water have growth inducing ability and favourably influenced the reproductive performance in terms of high fecundity, high fry survival, reduced fry mortality and reduced fry deformity.

Morphometric relationships of spineless cuttlefish, Sepiella inermis (Orbigny, 1848) from Mumbai waters

The relationships of various morphometric characters with dorsal mantle length (DML) of Sepiella inermis from Mumbai waters was established. The coefficient of correlation (r²) for various morphometric characters against dorsal mantle length ranged from 0.747 to 0.942 indicating high degree of relationship among the characters compared. The regression of characteristics obtained by least squares method for S. inermis indicates that the characters have positive allometric growth.