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| Chalde,Tomás; Elisio,Mariano; Miranda,Leandro A.. |
| The aim of this work was to assess the quality of pejerrey eggs and larvae throughout its spawning season. Fertilized eggs were taken on September, October, November, and December from a captive broodstock. The egg diameter, yolk diameter, and oil droplets area decreased along the spawning season, with higher values in September. Fertilization and hatching rates decreased throughout this period, with highest values in September (88.0%; 55.2%) and the lowest values on December (43.0%; 25.2%). The larvae hatched from eggs obtained on October were the heaviest and longest (1.57 mg; 8.24 mm). The survival rate at 30 days post hatching (dph) was similar in larvae from September and October eggs (66.1%; 62.9%) with a sharp decrease in larvae from November and... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Aquaculture; Eggs and larvae quality; Pejerrey; Reproductive season. |
| Ano: 2014 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1679-62252014000300629 |
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| Piedras,Sérgio Renato Noguez; Pouey,Juvêncio Luís Osório Fernandes; Moraes,Paulo Roberto Rocha; Cardoso,Daniela Fençon. |
| Ammonia results from decomposition of effluents organic matter, e.g. feed wastes and fish faeces. Its un-ionized form can be toxic because diffuses easily through fish respiratory membranes, damaging gill epithelium and impairing gas exchanges. The objective of this work was determining the 96-hour CL50 of un-ionized ammonia for newly hatched pejerrey Odontesthes bonariensis larvae. Trials were set up completely randomized design, with three different concentration of un-ionized ammonia (0.57, 0.94, and 1.45 mg L-1 NH3-N) and a control treatment (n = 3). Experimental units were 20-L, aerated aquaria stocked with 20 larvae (average weight 3.9 mg). Pejerrey larvae exposed to un-ionized ammonia during 96 hours present 50% mortality at 0.71 mg L-1 NH3-N. |
| Tipo: Info:eu-repo/semantics/report |
Palavras-chave: Pejerrey; Odontesthes bonariensis; Toxicity; Nitrogen; Larvae. |
| Ano: 2006 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162006000200011 |
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| Tsuzuki,M.Y.; Ogawa,K.; Strüssmann,C.A.; Maita,M.; Takashima,F.; Melo,C.M.R.. |
| The role of cortisol on the osmoregulation of pejerrey Odontesthes bonariensis at different salinities was investigated in adult fish injected with 0.7mg hydrocortisone per 100g body weight of fish, and transferred to 0, 5 and 20ppt of NaCl. Blood cortisol was 566ng/ml at the beginning of the experiment (0h) but surged to 1250ng/ml within 3h in cortisol-injected fish. Cortisol levels were influenced not only by treatment but also by time, being higher at 3h compared to 24h. Salinity level, time of exposure and their interaction, but not cortisol treatment, significantly affected plasma osmolality and the concentration of ions Cl- and Na+. This study showed that exogenous cortisol does not seem to play a significant role on the regulation of plasma... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Pejerrey; Odontesthes bonariensis; Cortisol; Osmoregulation; Salinity. |
| Ano: 2007 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0102-09352007000500030 |
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