Physiological responses to hyper-saline waters in sailfin mollies (Poecilia latipinna)

Gonzalez, Richard J.; Cooper, Jill; Head, D.

doi:10.1016/j.cbpa.2005.08.008

Cited by 40 publications

(30 citation statements)

References 25 publications

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“…and Cl -concentrations only about 50%, higher than levels for fish at 35 ppt (Sardella et al 2004b). Similar results have been obtained for sailfin mollies, Goldspotted killifish (Floridichthys carpio), Sheepshead minnow, Arabian killifish, and California killifish (Valentine and Miller 1969;Griffith 1974;Nordlie 1985;Nordlie and Walsh 1989;Jordan et al 1993;Gonzalez et al 2005). In a couple of these studies (Sardella et al 2004a;Gonzalez et al 2005), muscle tissue water content was also measured and they found that it did not fall at all or only slightly (5%) at the highest salinities (85-95 ppt), which indicates that despite the elevations in plasma ion concentrations fish are avoiding the internal fluid shift disturbances that can be problematic.…”

Section: Physiology Of Hyper-saline Tolerant Fishsupporting

confidence: 82%

“…Similar results have been obtained for sailfin mollies, Goldspotted killifish (Floridichthys carpio), Sheepshead minnow, Arabian killifish, and California killifish (Valentine and Miller 1969;Griffith 1974;Nordlie 1985;Nordlie and Walsh 1989;Jordan et al 1993;Gonzalez et al 2005). In a couple of these studies (Sardella et al 2004a;Gonzalez et al 2005), muscle tissue water content was also measured and they found that it did not fall at all or only slightly (5%) at the highest salinities (85-95 ppt), which indicates that despite the elevations in plasma ion concentrations fish are avoiding the internal fluid shift disturbances that can be problematic. One way to avoid osmotic disturbances is to accumulate osmolytes in the intra-cellulary fluid, and one study has shown elevated levels of the osmolyte glycine in muscle tissue and myoinositol in brain tissue of Mozambique tilapia at 70 ppt (Fiess et al 2007), which suggests an acclimation response to hyper-salinity rather than a pathological consequence of exposure.…”

Section: Physiology Of Hyper-saline Tolerant Fishsupporting

confidence: 82%

“…The typical pattern ( Fig. 1) shows plasma ion levels rising slowly, or not at all up to about 70-75 ppt, then climbing more steeply in a more or less linear fashion at higher salinities (Jordan et al 1993;Nordlie 1985;Nordlie et al 1992;Sardella et al 2004b;Gonzalez et al 2005). Still, even at the highest salinities the elevations in plasma ion concentrations are small compared to the surrounding waters.…”

Section: Physiology Of Hyper-saline Tolerant Fishmentioning

confidence: 87%

“…Rates of water loss, as indicated by drinking rate, increase with salinity, but at a slow rate. For example, sailfin mollies at 60 ppt, where the osmotic gradient across the gills is double that in seawater, had a drinking rate only 35% higher than in seawater (Gonzalez et al 2005). At 80 ppt, where the osmotic gradient is almost triple, drinking rate is less than double that in seawater.…”

Section: Physiology Of Hyper-saline Tolerant Fishmentioning

confidence: 97%

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The physiology of hyper-salinity tolerance in teleost fish: a review

Gonzalez

2011

J Comp Physiol B

116

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Hyper-saline habitats (waters with salinity >35 ppt) are among the harshest aquatic environments. Relatively few species of teleost fish can tolerate salinities much above 50 ppt, because of the challenges to osmoregulation, but those that do, usually estuarine, euryhaline species, show a strong ability to osmoregulate in salinities well over 100 ppt. Typically, plasma Na(+) and Cl(-) concentrations rise slowly or not at all up to about 65 ppt. At higher salinities ion levels do rise, but the increase is small relative to the magnitude of increase in concentrations of the surrounding water. A number of adjustments are responsible for such strong osmoregulation. Reduced branchial water permeability is indicated by the observation that with the exposure to hyper-salinities drinking rates rise more slowly than the branchial osmotic gradient. Lower water permeability limits osmotic water loss and greatly reduces the salt load incurred in replacing it. Still, increased gut Na(+)/K(+)-ATPase (NAK) activity is necessary to absorb the larger gut salt load and increased HCO(3) (-) secretion is required to precipitate Ca(2+) and some Mg(2+) in the imbibed water to facilitate water absorption. All Na(+) and Cl(-) taken up must be excreted and increased branchial salt excreting capacity is indicated by elevated mitochondrion-rich cell density and size, gill NAK activity and expression of chloride channels. Excretion of Na(+) and Cl(-) occurs against a larger gradient than in seawater and calculation of the equilibrium potential for Na(+) across the gill epithelium indicates that the trans-epithelial potential required for excretion of Na(+) climbs with salinity up to about 65 ppt before leveling off due to the increasing plasma Na(+) levels. During acute transition to SW or mildly hyper-saline waters, some species have shown the ability to upregulate branchial NAK activity rapidly and this may play an important role in limiting disturbances at higher salinities. It does not appear that the opercular epithelium, which in SW acts in a way that is functionally similar to the gills, continues to do so in hyper-saline waters. Little is know about the hormones involved in acclimation to hyper-salinity, but the few studies available suggest a role for cortisol, but not growth hormone and insulin-like growth factor. Despite the increased transport capacity evident in both the gill and gut in hyper-saline waters there is no clear trend toward increased metabolic rate. These studies provide a general outline of the mechanisms of osmoregulation in these species, but significant questions still remain.

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Section: Physiology Of Hyper-saline Tolerant Fishsupporting

confidence: 82%

Section: Physiology Of Hyper-saline Tolerant Fishsupporting

confidence: 82%

Section: Physiology Of Hyper-saline Tolerant Fishmentioning

confidence: 87%

Section: Physiology Of Hyper-saline Tolerant Fishmentioning

confidence: 97%

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The physiology of hyper-salinity tolerance in teleost fish: a review

Gonzalez

2011

J Comp Physiol B

116

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“…from para-to trans-cellular routes) to accommodate the decreased osmotic permeability ( junctional leakiness) of branchial epithelia. Although I am not aware of any direct evidence for this conjecture it is indirectly supported by osmotic permeability and water balance studies on teleosts acclimated to hyperhalinity (Motais et al, 1966(Motais et al, , 1969Gonzalez et al, 2005;Laverty and Skadhauge, 2012). Interestingly, many species of euryhaline fish have upper salinity tolerance thresholds of about 2× seawater (Schultz and McCormick, 2013), which suggests that only the most euryhaline species that tolerate salinities well above 2× seawater have evolved the capacity for qualitatively changing their osmoregulatory strategy when encountering extremely hyperhaline conditions.…”

Section: −1mentioning

confidence: 97%

Physiological mechanisms used by fish to cope with salinity stress

Kültz

2015

Journal of Experimental Biology

324

161

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Salinity represents a critical environmental factor for all aquatic organisms, including fishes. Environments of stable salinity are inhabited by stenohaline fishes having narrow salinity tolerance ranges. Environments of variable salinity are inhabited by euryhaline fishes having wide salinity tolerance ranges. Euryhaline fishes harbor mechanisms that control dynamic changes in osmoregulatory strategy from active salt absorption to salt secretion and from water excretion to water retention. These mechanisms of dynamic control of osmoregulatory strategy include the ability to perceive changes in environmental salinity that perturb body water and salt homeostasis (osmosensing), signaling networks that encode information about the direction and magnitude of salinity change, and epithelial transport and permeability effectors. These mechanisms of euryhalinity likely arose by mosaic evolution involving ancestral and derived protein functions. Most proteins necessary for euryhalinity are also critical for other biological functions and are preserved even in stenohaline fish. Only a few proteins have evolved functions specific to euryhaline fish and they may vary in different fish taxa because of multiple independent phylogenetic origins of euryhalinity in fish. Moreover, proteins involved in combinatorial osmosensing are likely interchangeable. Most euryhaline fishes have an upper salinity tolerance limit of approximately 2× seawater (60 g kg −1). However, some species tolerate up to 130 g kg −1 salinity and they may be able to do so by switching their adaptive strategy when the salinity exceeds 60 g kg −1. The superior salinity stress tolerance of euryhaline fishes represents an evolutionary advantage favoring their expansion and adaptive radiation in a climate of rapidly changing and pulsatory fluctuating salinity. Because such a climate scenario has been predicted, it is intriguing to mechanistically understand euryhalinity and how this complex physiological phenotype evolves under high selection pressure.

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Hypersaline Environments

Laverty

Skadhauge

2014

Extremophile Fishes

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Physiological responses to hyper-saline waters in sailfin mollies (Poecilia latipinna)

Cited by 40 publications

References 25 publications

The physiology of hyper-salinity tolerance in teleost fish: a review

The physiology of hyper-salinity tolerance in teleost fish: a review

Physiological mechanisms used by fish to cope with salinity stress

Hypersaline Environments

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