Embryonic and larval development of brown trout, Salmo trutta L.: exposure to aluminium, copper, lead or zinc in soft, acid water

Abstract

Freshly fertilized ova, eyed ova and yolk-sac fry of brown trout, Salmo truifa L., were exposed to each of four trace metals (aluminium: 6000 nmol I -I ; copper: 80 nmol I-'; lead: 50 nmol I-'; zinc: 300 nmol I-I) while held in flowing artificial soft-water media maintained at pH 4.5 or 5.6 and [Ca] 20 or 200 pmol I-'. In continuous exposure from fertilization, survival of ova was severely affected at pH 4.5 and [Ca] 20 pmol I -I , regardless of the presence of Cu, Pb or Zn; A1 reduced embryonic mortality and improved hatching success. High ambient [Ca] at pH 4.5 increased egg survival. At ' swim-up ', surviving fry exposed to A1 or Pb had lower whole body Ca, Na and K content, irrespective ofpH or ambient [Ca]. Cu reduced whole body Ca and K content at pH 5.6 and [Ca] 200 pmol-I, and whole body Ca, Na and K content in the other media. Zn reduced whole body mineral content at pH 5.6 and [Ca] 20 pmol I-'. Whole body Mg content was reduced by all trace metals at pH 5.6 and [Ca] 20 pmol I-', and by Cu at pH 5.6 and [Ca] 200 p o l I-I. Al and Cu impaired skeletal calcification at pH 5.6 at both ambient [Ca]; Pb only at [Ca] 20 pmol I-'. Zn enhanced calcification at pH 4.5 and [Ca] 200 pmol I-'. In the absence of trace metals, low pH reduced body Ca, Na, Kcontent and skeletalcalcificationat [Ca] 200 pmol I-'. The uptake ofCa, Na and K, measured at regular intervals from hatching was impaired to the same extent by all treatments at pH 4.5, irrespective ofambient [Ca] or trace metal presence. At pH 5.6, irrespective of ambient [Ca], Al, Cu and Pb impaired Ca and K uptake. The rate of Na uptake was reduced by A1 and Cu. Al-treated yolk-sac fry, exposed to low ambient [Ca] from 200-300"days post-hatch, suffered high mortalities regardless of pH. Ca, Na and K uptake was impaired by all treatments at pH 4.5, and by A1 and Cu at pH 5.6 in a similar exposure period. The development of the early stages of brown trout in the presence of trace metals is discussed in relation to recruitment failure in areas of soft. acid water.

Freshwater acidification: effects on the early life stages of fish

“…In that study, whole-body potassium concentrations of eyed eggs remained unaffected, and it is possible that the uptake of other minerals may be increased to compensate for sodium loss. No differences in whole-body sodium, potassium, calcium or magnesium concentrations were recorded for brown trout eggs maintained in soft (20 Ixmol 1-1 calcium), acid (pH 4.5) media with or without copper, zinc, lead or aluminium (Sayer et al, 1991a), although the advanced state of the eggs used in the latter study may explain in part the lack of effect. It is generally accepted that the eyed egg stage is more resistant to the conditions associated with acid water than is the green egg stage (see Mortality section, page 108).…”

“…There are, however, reports of accelerated incubation times at low pH for brook trout (Trojnar, 1977b;Jordahl and Benson, 1987) and brown trout (Sayer et aL, 1991a), but also experiments where incubation time was independent of treatment for Atlantic salmon (Daye and Garside, 1979) and brown trout (Sadler and Lynam, 1988). Although the majority of reports suggest that incubation is prolonged in acid water, experimental conditions such as water quality, origin of eggs and/or control of temperature vary considerably.…”

“…1). This condition has been observed for hatching Atlantic salmon Garside, 1977, 1979;Johansson et al, 1977;Peterson et al, 1980a;Peterson and Martin-Robichaud, 1983), chinook salmon (Geen et al, 1985), brook trout (Kwain and Rose, 1985;Jordahl and Benson, 1987;Cleveland et al, 1989;Ingersoll et al, 1990a;Steingraeber and Gingerich, 1991), brown trout (Johannson et al, 1977;Brown and Lynam, 1981;Sadler and Lynam, 1988;Sayer et al, 1991a) and rainbow trout (Nelson, 1982) subjected to acid water, with or without trace metals. Encapsulation may be temporary.…”

The Bioavailability and Toxicity of Aluminum in Aquatic Environments

“…Thus, understanding the toxicities of combinations of metals is not necessarily intractable. Sayer et al (1991c) found that Cu (5 µg · L -1 , 0.08 µM), Pb (10 µg · L -1 , 0.05 µM), and Al (160 µg · L -1 , 5.9 µM) caused brown trout fry mortalities and impaired skeletal calcification in synthetic soft water, but Zn did not (20 µg · L -1 Zn, 0.31 µM; pH ~5.6, 20 µM Ca).…”

Immunological parameters of Javanese carp Puntius gonionotus (Bleeker) exposed to copper and challenged withAeromonas hydrophila

“…Copper at sublethal levels have been recognised as a stressor causing immunosuppression in fish (Ellis, 1989) resulting in increased susceptibility to infectious diseases (Mazeaud et al, 1977;Zeliko#, 1993). In fish, copper accumulates in haemopoietic and lymphoietic tissues inhibiting their growth, metabolic activity, fecundity, gonadal development (Sayer et al, 1992), and suppresses the immune activities (Anderson et al, 1989;Hossain & Shari#, 1992). However, the e#ects of sublethal concentrations of metals on integrated physiological processes in fish, such as immunocompetency, are not well understood (Dethlo# & Bailey, 1998).…”