scholarly journals Combined Effects Of Temperature And Salinity On Egg Hatching Rate And Incubation Time Of Penaeus Semisulcatus (Decapoda: Penaeidae)

Author(s):  
M. Kumluo ◽  
O.T. Eroldogan ◽  
M. Aktas
2007 ◽  
Vol 4 (1) ◽  
pp. 57 ◽  
Author(s):  
T. Budiardi ◽  
W. Cahyaningrum ◽  
I. Effendi

<p>This study was performed to determine the efficiency of yolk egg utilization in embryos and larvae, hatching rate, incubation time to hatch, and growth rate of maanvis (<em>Pterophyllum scalare</em>) larvae incubated at room remperature, 27<sup>o</sup>C, and 30<sup>o</sup>C.  Results of study showed that yolk egg utilization efficiency of embryos and larvae incubated at 30<sup>o</sup>C was 73.70% and 0,18%, respectively, and no different with that of room and 27<sup>o</sup>C incubation temperatures.  Hatching rate of eggs incubated at 30<sup>o</sup>C (84.75%) was also same with that of other treatments.  However, incubation time to hatch (27.41 hours) was shorter than that of other treatments.  The growth rate by length of larvae (2.16%) and survival rate (75.28%) incubated at 30<sup>o</sup>C was also higher compared with that of other treatments.  Thus, in general, optimum temperature for egg hatching and larval rearing of maanvis was 30<sup>o</sup>C.</p> <p>Keywords: maanvis, <em>Pterophyllum scalare</em>, egg yolk, larvae, embryo, temperature</p> <p> </p> <p>ABSTRAK</p> <p>Penelitian ini dilakukan untuk mengetahui efisiensi pemanfaatan kuning telur pada embrio dan larva, derajat penetasan, lama inkubasi telur hingga menetas, dan laju pertumbuhan serta kelangsungan hidup larva ikan maanvis (<em>Pterophyllum scalare</em>) yang diinkubasi pada suhu ruang, 27<sup>o</sup>C dan 30<sup>o</sup>C.  Hasil penelitian menunjukkan bahwa nilai efisiensi pemanfaatan kuning telur bila diinkubasi pada suhu 30<sup>o</sup>Csebesar 73,70% pada fase embrio dan 0,18% pada fase larva, dan tidak berbeda dengan suhu ruang dan 27<sup>o</sup>C.  Demikian juga dengan derajat penetasan telur  (84,75%) tidak berbeda dengan perlakuan lainnya.  Sementara itu, lama inkubasi telur hingga menetas (27,41 jam) lebih cepat dibandingkan dengan suhu inkubasi perlakuan lainnya. Demikian juga dengan laju pertumbuhan panjang (2,16%) dan kelangsungan hidup larva (75,28%) lebih tinggi dibandingkan dengan perlakuan lainnya. Dengan demikian, secara umum suhu optimal untuk penetasan dan pemeliharaan larva ikan maanvis adalah 30°C.</p> <p>Kata kunci: ikan maanvis, <em>Pterophyllum scalare</em>, kuning telur, larva, embrio, suhu</p>


Insects ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 109
Author(s):  
Norazila Yusoff ◽  
Idris Abd Ghani ◽  
Nurul Wahida Othman ◽  
Wan Mohd Aizat ◽  
Maizom Hassan

The diamondback moth, Plutella xylostella (L.) (Lepidoptera: Plutellidae), is the most important pest of cruciferous vegetables worldwide. In this study, we evaluated the properties of selected farnesyl derivative compounds against P. xylostella. The toxicity and sublethal concentration (LC50) of farnesyl acetate, farnesyl acetone, farnesyl bromide, farnesyl chloride, and hexahydrofarnesyl acetone were investigated for 96 h. The leaf-dip bioassays showed that farnesyl acetate had a high level of toxicity against P. xylostella compared to other tested farnesyl derivatives. The LC50 value was 56.41 mg/L on the second-instar larvae of P. xylostella. Then, the sublethal effects of farnesyl acetate on biological parameters of P. xylostella were assessed. Compared to the control group, the sublethal concentration of farnesyl acetate decreased pupation and emergence rates, pupal weight, fecundity, egg hatching rate, female ratio, and oviposition period. Furthermore, the developmental time of P. xylostella was extended after being exposed to farnesyl acetate. Moreover, the application of farnesyl acetate on P. xylostella induced morphogenetic abnormalities in larval–pupal intermediates, adults that emerged with twisted wings, or complete adults that could not emerge from the cocoon. These results suggested that farnesyl acetate was highly effective against P. xylostella. The sublethal concentration of farnesyl acetate could reduce the population of P. xylostella by increasing abnormal pupal and adults, and by delaying its development period.


Toxins ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 425
Author(s):  
Yunyu Tang ◽  
Haiyan Zhang ◽  
Yu Wang ◽  
Chengqi Fan ◽  
Xiaosheng Shen

This study assessed the impact of increasing seawater surface temperature (SST) and toxic algal abundance (TAA) on the accumulation, tissue distribution and elimination dynamics of paralytic shellfish toxins (PSTs) in mussels. Mytilus coruscus were fed with the PSTs-producing dinoflagellate A. catenella under four simulated environment conditions. The maximum PSTs concentration was determined to be 3548 µg STX eq.kg−1, which was four times higher than the EU regulatory limit. The increasing SST caused a significant decline in PSTs levels in mussels with rapid elimination rates, whereas high TAA increased the PSTs concentration. As a result, the PSTs toxicity levels decreased under the combined condition. Additionally, toxin burdens were assessed within shellfish tissues, with the highest levels quantified in the hepatopancreas. It is noteworthy that the toxin burden shifted towards the mantle from gill, muscle and gonad at the 17th day. Moreover, variability of PSTs was measured, and was associated with changes in each environmental factor. Hence, this study primarily illustrates the combined effects of SST and TAA on PSTs toxicity, showing that increasing environmental temperature is of benefit to lower PSTs toxicity with rapid elimination rates.


2004 ◽  
Vol 35 (12) ◽  
pp. 1131-1140 ◽  
Author(s):  
Cecilia Flores-Vergara ◽  
Beatriz Cordero-Esquivel ◽  
Ana Nallely Ceron-Ortiz ◽  
Bertha O Arredondo-Vega

2010 ◽  
Vol 132 (11) ◽  
Author(s):  
A. Arikoglu ◽  
G. Komurgoz ◽  
I. Ozkol ◽  
A. Y. Gunes

The present work examines the effects of temperature and velocity jump conditions on heat transfer, fluid flow, and entropy generation. As the physical model, the axially symmetrical steady flow of a Newtonian ambient fluid over a single rotating disk is chosen. The related nonlinear governing equations for flow and thermal fields are reduced to ordinary differential equations by applying so-called classical approach, which was first introduced by von Karman. Instead of a numerical method, a recently developed popular semi numerical-analytical technique; differential transform method is employed to solve the reduced governing equations under the assumptions of velocity and thermal jump conditions on the disk surface. The combined effects of the velocity slip and temperature jump on the thermal and flow fields are investigated in great detail for different values of the nondimensional field parameters. In order to evaluate the efficiency of such rotating fluidic system, the entropy generation equation is derived and nondimensionalized. Additionally, special attention has been given to entropy generation, its characteristic and dependency on various parameters, i.e., group parameter, Kn and Re numbers, etc. It is observed that thermal and velocity jump strongly reduce the magnitude of entropy generation throughout the flow domain. As a result, the efficiency of the related physical system increases. A noticeable objective of this study is to give an open form solution of nonlinear field equations. The reduced recurative form of the governing equations presented gives the reader an opportunity to see the solution in open series form.


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