An Environmental Factor Stimulating Salinity Tolerance and Branchial Chloride Cells in a Euryhaline Teleost <i>Poecilia reticulata</i>

Abstract

The present study examined a factor in seawater which stimulates salinity tolerance and the num ber and size of branchial chloride cells in the guppy. Salinity tolerance was measured as LD50 24 h after transfer to serial concentrations of salinity. LD50 significantly increased from 25.8 ppt to 43.3 ppt 5 days after exposure to 15 ppt dilute seawater. Thus, increases of salinity tolerance were examined on the basis of 5 days' exposure to various solutions which were contained within 15 ppt dilute seawater. LD50 significantly increased in 0.180 M NaCl and 0.023 M MgCl2 but not in 0.012 M Na2SO4, 0.004 M CaCl2, or 0.004 M KCl. During 5 days' exposure to 0.090 M MgCl2, 0,090 M Na2SO4, 0.090 M CaCl2, or 0.180 M KCl which contain the same Na+ or Cl concentrations as 0.180 M NaCl, all guppies died in 0.180 M KCl. Using mixtures of NaCl and KCl, it was revealed that more than 0.020 M K+ caused death of the guppies. LD50 did not change after exposure to 0.090 M Na2SO4 which contains the same Na+ concentra tion as 0.180 M NaCl but significantly increased after exposure to 0.090 M MgCl2 and 0.090 M CaCl2 which contain the same Cl concentration as 0.180 M NaCl. The number and size of chloride cells did not change in 0.090 M Na2SO4 but significantly increased in 0.180 M NaCl, 0.090 M MgCl2, and 0.090 M CaCl2. These results suggested that environmental Cl stimulates salinity tolerance and the number and size of branchial chloride cells in the guppy.

Dietary effect on fry production and growth performance of sailfin molly, Poecilia latipinna, in salt water

“…Several investigators have demonstrated the wide salinity tolerance of poeciliid fishes such as P. reticulata (cf. Arai et al 1998), Limia melanonotata (cf. Haney and Walsh 2003), P. sphenops (cf.…”

Effect of salinity on gestation period, fry production, and growth performance of the sailfin molly (Poecilia latipinna lesueur) in captivity

“…Salinity is a major influencing factor on reproductive physiology in fishes (Ellis et al, 1997;Watanabe et al, 1998;Claireaux and Lagardere, 1999). Although several investigators reported salinity tolerance of poeciliid fishes (Kristensen, 1969;Nordlie et al, 1992;Arai et al, 1998), no scientific work on the effect of salinity on breeding and growth performance of P. latipinna has been done. The goal of the present study was to assess the effect of salinity on breeding and growth performance of P. latipinna in captive conditions.…”