GROWTH OF PIKE-PERCH SANDER LUCIOPERCA (L., 1758) (PERCIDAE) IN RESERVOIRS OF K. SATPAYEV’S CHANNEL

Author(s):  
Saule Zhangirovna Asylbekova ◽  
Kuanysh Baibulatovich Isbekov ◽  
Vladimir Nickolaevich Krainyuk

Pike-perch is an invader for the water basins of Central Kazakhstan. These species have stable self-reproductive populations in the regional waters. Back calculation method was used to investigate pike-perch growth rates in reservoirs of K. Satpayev’s channel. For comparison, the data from the other water bodies (Vyacheslavsky and Sherubay-Nurinsky water reservoirs) were used, as well as literature data. Pike-perch species from the investigated waters don’t show high growth rates. The populations from the reservoirs of K. Satpayev’s channel have quite similar growth rates with populations from the Amur river, from a number of reservoirs in the Volga river basin and from the reservoir in Spain. Sexual differences in growth have not been observed. Evaluating possible influence of various abiotic and biotic factors on the growth rate of pike-perch in the reservoirs of K. Satpayev’s channel was carried out. It has been stated that the availability of trophic resources cannot play a key role in growth dynamics because of their high abundance. Morphology of water bodies also does not play a role, as well as chromaticity, turbidity and other optical water indicators. It can be supposed that the main factor influencing growth of pike perch is the habitat’s temperature. This factor hardly ever approaches optimal values for the species in reservoirs of K. Satpaev’s channel. The possible influence of fishing selectivity on pike-perch growth rates was also evaluated. Currently, there has been imposed a moratorium on pike-perch catch. However, pike-perch is found in by-catches and in catches of amateur fishermen. It should be said that such seizures have an insignificant role in the dynamics of growth rates.

Author(s):  
Nikolay Aleksandrovich Pudovkin ◽  
Peter Vladimirovich Smutnev

The authors of the article have studied the content of the elements of anti-oxidant system (malondialdehyde, catalase, selenium) in tissues of the internal organs (gills, intestine, muscles, liver, swimbladder, scales) in some species of predatory fish (pike Esox lucius (L., 1758), perch Perca fluviatilis (L., 1758), pike-perch Sander lucioperca (L., 1758), catfish Silurus glanis ) widespread in the basin of the Volga river in the Saratov region. The lowest concentration of malondialdehyde in organisms of the studied fish species is observed in fall and winter; the highest - in spring and summer. Catalase activity in gills tissue of a pike raised in 11.8%, cat-fish - 9.1%, pike-perch - 7.5%, perch - 7.8%. In fall (compared to winter) enzyme activity lowering in gonads of pike-perch makes 16.3%, in gonads of perch - 14.4%. In other tissues there were not observed any evident changes of catalase activity. Fish species under consideration are listed according to the average value of selenium concentration in organisms, µg/g: pike (0.208) > catfish (0.207) > pike-perch (0.196) > perch (0.178). According to the average value of the selenium accumulation in the body in different season all the studied species can be placed in the following order, µg/g: winter-pike (0.132) > pike-perch (0.136) > perch and catfish (0.142); spring - pike-perch (0.190) > perch (0.191) > pike (0.208) > catfish (0.209); summer - perch (0.186) > pike-perch (0.190) > catfish and pike (0.203); autumn - perch (0.193) > pike-perch (0.268) > > catfish (0.274) > pike (0.289).


1967 ◽  
Vol 24 (12) ◽  
pp. 2573-2594 ◽  
Author(s):  
David G. Patriquin

Gadus morhua L. occurs in Ogac Lake, a salt, meromictic lake on Baffin Island that receives influxes of seawater only during the highest summer tides. Cod of the order of 10,000 of lengths 25 cm and greater and 500 of lengths greater than 60 cm were present. The size ranges for various ages far exceeded those of oceanic populations. Feeding conditions were poor, and sea urchins predominated in the diet. Large cod (greater than 50 cm) were highly cannibalistic, and it was estimated that they consume of the order of 3500 fish of 20–40 cm annually. Maturation occurred at the unusually large size of 85 cm in females, and at about 65 cm in males. Apparently many of the cod never reach these sizes. Spawning was from late May to early July in 1962, and initiation of spawning appeared to be related to light. The hatching of cod larvae coincided with the appearance of the nauplii of the dominant copepod in the lake. Egg size was highly variable and exhibited a curious bimodalism. Variation in vertebral and fin-ray counts was slight in spite of high environmental variability, and thus appears largely genetically controlled. Possibly the first inhabitants came from Greenland stocks, which have high growth rates similar to the faster growing cod in the lake, and similar high length at maturity. Meristic characters also suggest affinity with Greenland rather than Labrador cod. The hydrography of the area and the possibilities of larval drift or adult migration into the lake are discussed. Cannibalism must exert continuing selection for high growth rates, but very poor feeding conditions and hierarchial dominance effects probably prevent general attainment of high growth rates.


2001 ◽  
Vol 67 (4) ◽  
pp. 1839-1845 ◽  
Author(s):  
Martin L. Saker ◽  
Brett A. Neilan

ABSTRACT The potentially toxic freshwater cyanobacteriumCylindrospermopsis raciborskii has become increasingly prevalent in tropical and temperate water bodies worldwide. This paper investigates the effects of different nitrogen sources (NO3 −, NH4 +, and omission of a fixed form of nitrogen) on the growth rates, morphologies, and cylindrospermopsin (CYL) concentrations (expressed as a percentage of the freeze-dried weight) of seven C. raciborskii isolates obtained from a range of water bodies in northern Australia and grown in batch culture. In general, growth rates were lowest in the absence of a fixed-nitrogen source and highest with NH4 + as the nitrogen source. Conversely, the highest concentrations of CYL were recorded in cultures grown in the absence of a fixed-nitrogen source and the lowest were found in cultures supplied with NH4 +. Cultures supplied with NO3 − were intermediate with respect to both CYL concentration and growth rate. Different nitrogen sources resulted in significant differences in the morphology of C. raciborskii trichomes. Most notable were the loss of heterocysts and the tapering of end cells in cultures supplied with NH4 + and the statistically significant increase in vegetative cell length (nitrogen depleted < NO3 − < NH4 +). The morphological changes induced by different nitrogen sources were consistent for all isolates, despite measurable differences in vegetative-cell and heterocyst dimensions among isolates. Such induced morphological variation has implications forCylindrospermopsis taxonomy, given that distinctions between species are based on minor and overlapping differences in cell lengths and widths. The close phylogenetic association among all seven isolates was confirmed by the high level (>99.8%) of similarity of their 16S rRNA gene sequences. Another genetic technique, analysis of the HIP1 octameric-palindrome repeated sequence, showed greater heterogeneity among the isolates and appears to be a useful method for distinguishing among isolates of C. raciborskii.


2000 ◽  
Vol 266-269 ◽  
pp. 450-454 ◽  
Author(s):  
Yoram Lubianiker ◽  
Yanyang Tan ◽  
J.David Cohen ◽  
Gautam Ganguly

2008 ◽  
Vol 600-603 ◽  
pp. 115-118 ◽  
Author(s):  
Henrik Pedersen ◽  
Stefano Leone ◽  
Anne Henry ◽  
Franziska Christine Beyer ◽  
Vanya Darakchieva ◽  
...  

The chlorinated precursor methyltrichlorosilane (MTS), CH3SiCl3, has been used to grow epitaxial layers of 4H-SiC in a hot wall CVD reactor, with growth rates as high as 170 µm/h at 1600°C. Since MTS contains both silicon and carbon, with the C/Si ratio 1, MTS was used both as single precursor and mixed with silane or ethylene to study the effect of the C/Si and Cl/Si ratios on growth rate and doping of the epitaxial layers. When using only MTS as precursor, the growth rate showed a linear dependence on the MTS molar fraction in the reactor up to about 100 µm/h. The growth rate dropped for C/Si < 1 but was constant for C/Si > 1. Further, the growth rate decreased with lower Cl/Si ratio.


Author(s):  
Mahesh Brahmadesham Venkataraman ◽  
Alireza Rahbari ◽  
Philip J van Eyk ◽  
Alan W. Weimer ◽  
Wojciech Lipiński ◽  
...  

Algal biomass is an attractive feedstock for carbon-neutral fuel production due to high growth rates and its potential to be farmed in artificial ponds on non-arable land. Supercritical water gasification...


Author(s):  
Laura Härkönen ◽  
Pauliina Louhi ◽  
Riina Huusko ◽  
Ari Huusko

Understanding the dynamic nature of individual growth in stream-dwelling salmonids may help forecast consequences of climate change on northern fish populations. Here, we performed an experimental capture-mark-recapture study in Atlantic salmon to quantify factors influencing wintertime growth variation among juveniles under different scenarios for ice cover reduction. We applied multiple imputation to simulate missing size observations for unrecaptured fish, and to account for individual-level variation in growth rates. The salmon parr exhibited substantial body length shrinkage in early winter, suppressed growth through mid-winter, and increasing growth rates in late winter and particularly in spring. Unexpectedly, the presence of ice cover had no direct effects on wintertime growth. Instead, our results implied increasing energetic costs with reducing ice cover: individuals exposed to absent or shortened ice-covered period gained mass at a lowered rate in spring whereas the present, long ice-covered period was followed by rapid growth. This study emphasizes natural resilience of Atlantic salmon to wintertime environmental variation which may help the species to cope with the reductions in ice cover duration due to climate change.


Author(s):  
Marko J. Tadjer ◽  
Fikadu Alema ◽  
Andrei Osinsky ◽  
Michael Mastro ◽  
Neeraj Nepal ◽  
...  
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