Impact of pulp and paper mill effluent on egg hatchability of pike (Esox lucius L.)
Toxicants affect reproduction often at concentrations well below lethal levels. Also, the acidification of fresh waters has been shown to cause extinction of teleost fish populations usually through a failure of recruitment from younger generations. Both field and laboratory studies have documented that the greatest susceptibility to low pH occurs in the early developmental stages (e.g. Lee et al. 1983; Peterson 1984). Also low concetrations of metals (Horning & Neisel 1979; Ozoh 1979, 1980) and environmental accumulation of xenobiotics (Ozoh 1979; yon Westerhagen et al. 1981) diminish egg hatchability. In numerous toxicological studies egg hatchability has been a more sensitive indicator of toxic action than the other parameters studied (e.g. Henderson et al. 1981; DeGraeve et al. 1982; Lewis & Wee 1983). However, only relatively recently have the effects of bleached kraft pulp mill effluent (BKME) on fish reproduction (zebrafish Branchydanio rerio) been studied (Viktor et al. 1980; Viktor 1982) and no recipient species have been used.
Influence of Varying pH and some Inorganic Cations on the Perivitelline Potential of Eggs of Atlantic Salmon (Salmo salar)
A potential difference is maintained between the perivitelline fluid of the Atlantic salmon (Salmo salar) egg and the incubation medium. The magnitude of this potential difference depends on the ionic composition of the incubation medium; it exhibits a maximal negativity in deionized water, then depolarizes, and finally reverses in sign as the ionic content of the incubation medium is raised. The potential difference obeys the Nernst relationship over a limited concentration range of H+, Ca2+, and Mg2+ (10−5 to 10−3M). The maximal change in potential difference with change in Na+ and K+ concentrations is less than that predicted by the Nernst equation. The potential difference permits calculation of the degree of concentration of cations in the perivitelline fluid over that of the ambient medium. Depolarizing the perivitelline potential by lowering the ambient pH will result in losses of other cations from the perivitelline fluid.
Embryo Movements of Atlantic Salmon (Salmo salar) as Influenced by pH, Temperature, and State of Development
Two types of embryo movements of Atlantic salmon (Salmo salar), pectoral fin flutter and trunk movements, were measured as a function of incubation temperature, pH, and developmental state. Trunk movements began at 200 degree-days, initially at highest frequency. The frequency decreased throughout subsequent development and then increased slightly just before hatching. Movements were much more stereotyped in the earliest stages of development than just prior to hatching. Frequencies at 200 degree-days were insensitive to temperature and pH. Frequencies just prior to hatching were very temperature sensitive (Q10 of 13) and were decreased at low pH. This decreased frequency may be related to documented effects of temperature and low pH on hatching. Pectoral fin movements were temperature sensitive (Q10 of 2) and pH insensitive. These movements were initiated at 350 degree-days of development and attained maximal frequency at 400 degree-days.