salinity effects on osmoregulation and growth of the euryhaline flounder paralichthys orbignyanus

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1 Salinity effects on osmoregulation and growth of the euryhaline flounder Paralichthys orbignyanus 鹽鹽鹽鹽鹽鹽鹽鹽鹽 Paralichthys orbignyanus 鹽鹽鹽鹽鹽鹽鹽鹽鹽鹽 Lui's Andre´ Sampaio a , Adalto Bianchini b,* Journal of Experimental Marine Biology and Ecology 269(2002) 187-196 Reporter:Hui-ting Zhuang

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Salinity effects on osmoregulation and growth of the euryhaline flounder Paralichthys orbignyanus. 鹽度對廣鹽性比目魚 Paralichthys orbignyanus 之 滲透壓調節與成長影響. Introduction. Paralichthys orbignyanus. Family : Paralichthyidae Order : Pleuronectiformes Class : Actinopterygii - PowerPoint PPT Presentation


  • Salinity effects on osmoregulation and growth of the euryhaline flounder Paralichthys orbignyanusParalichthys orbignyanus

    Lui's Andre Sampaioa , Adalto Bianchinib,*

    Journal of Experimental Marine Biology and Ecology269(2002) 187-196

    Reporter:Hui-ting Zhuang

  • Introduction

  • Paralichthys orbignyanusFamily : ParalichthyidaeOrder : PleuronectiformesClass : ActinopterygiiMax. size:50.0 cm NG (male/unsexed; Ref. 36453); 38 cm TL (female) Environment:demersal; oceanodromous (Ref. 51243); brackish; marine; depth range 1 45 m Climate: subtropical; 23S - 41S

  • Distribution: Coastal and estuarine waters of Western South Atlantic Ocean (Brazil , Uruguay and Argentina)High market price. Wide tolerance to environmental factors such as salinity(0-40), pH , and nitrogenous compounds and acid stress.

    To evaluate the effect of hypo-(freshwater) and hyperosmotic (seawater) conditions on survival and growth.

  • Materials and methodsOsmo- and ionoregulatory studiesGrowth studies

  • Isosmotic point()

    Isoionic point()

  • Osmo- and ionoregulatory studiesCassino Beach(32S,52W)

  • 530,1020,30and 4015Average weight=176.019.5g


    300-lSix fish per tank


  • 1550ppm benzocain()1ml Osmotic analysisIonic analysisAnion (Cl-)titration()Cations(Na+,k+,Ca2+)

  • Growth studies




    X2X214 flounders per group.Water temperature was kept within 221C. 12L/12D4. 30 %.

  • Specific growth rate (SGR) =[( ln wf - ln wi ) / t x 100]wf = final weight (g)wi = initial weight (g)t = time (days).

    0306090EX wf = 38.85 (g)wi = 29.19 (g) t = 30 ()SGR = [( ln 38.85 - ln 29.19 ) / 30 x 100] = 0.953 % ()

  • BloodOsmolality and ionic composition (Na+ and Cl- ).GillNa+,k+ ATPaseGlass Teflon Potter homogenizer

    2 ml (250mM sucrose 20mMEDTA and pH7.4 Tris- HClbuffer)3C 1000 x g for 20minBianchiniand Castilho (1999)Castilho et al.(2001)

  • ResultsOsmo- and ionoregulatory studiesGrowth studies

  • Osmo- and ionoregulatory studies

  • Isosmotic point = 328.6 mOsm kg-1 10.9

  • Isoionic point =210.8 mEq l-111.6

  • Isoionic point = 136.8 mEq l-1 8.4

  • Isoionic point = 5.41 mEq l-1 22.6

  • Isoionic point = 5.21 mEq l-115.7

  • Paralichthys orbignyanus


  • Growth studiesNo significant between replicates for both flounder survival and growth over 90-day test.Survival was not significantly affected by salinity, since, at the end of the 90-day test, it was 92.9 % in both freshwater and seawater.

  • Discussion

  • The isosmotic point of P. orbignyanus was estimated as 328.6 mOsm kg-1 H2O and corresponded to 10.9 salinity.

    Stenohaline freshwater teleostsStenohaline marine teleosts260 mOsm kg-1H2O330 mOsm kg-1H2O370 mOsm kg-1H2O480 mOsm kg-1H2OP.orbignyanus321 mOsm kg-1H2O( 0 )370 mOsm kg-1H2O( 40 )

  • It is described that environment stressors such as salinity can effect fish growth (Borski et al.,1994).P.orbingnyanusP.orbingnyanus

  • Paralichthys. orbignyanus 0 40 Paralichthys. lethostigmaSouthern flounder 0 Paralichthys.dentatusSummer flounder 5 50

  • Conclusions

  • P. orbignyanus can be characterized as a marine/estuarine euryhaline teleost capable of carrying hyper/hypo iono- and osmoregulation over the fluctuating salinity regime faced by this species in the environment.Long-term exposure to freshwater induces a reduction in growth rate of P. orbignyanus, possibly due to an increase in energy expenditure associated to the osmo- and ionoregulation under this salinity condition.

  • ~The end~Thank you for your attention