Effects of reduced oxygen level on the mortality and hatching rate of Chondrostoma nasus embryos

Abstract

Exposure of embryos of Chondrostoma nasus to a strongly reduced oxygen content (about 10% of air saturation) enhanced mortality and depressed hatching success. Viable larvae hatched only from the controls and from the group exposed to reduced oxygen during the earliest embryogenesis (from fertilization to gastrula). In the groups exposed from gastrula to eyed stage and from eyed stage to hatching, a high percentage of fish hatched, but all were deformed and almost all died during the following 1-5 days. Hatching period was prolonged in the groups exposed to reduced oxygen content. At a spawning area C. nasus had deposited a large portion of eggs in areas of reduced oxygen content. On the other hand, eggs placed at the substratum surface were exposed to high predation pressure from Barbus barbus, Lota lota and ducks (Anas platyrhynchos). The trade-off between predation pressure at the substratum surface and reduced oxygen conditions in the interstices resulted in a narrow space for successful development of embryos of this endangered rheophilic fish species under natural conditions. 1996 The Fisheries Society of the British Isles

Effect of temperature on early life history in weatherfish,Misgurnus fossilis(L. 1758)

“…A summarized comparison of the hatching period amplitude reached in our study with data known from literature (in relation to temperature) is given in Figure 4 (values presented by Watanabe et al (1948) and Wang et al (2008) serve as the reference figures for hatching in temperature range 25-30 °C in M. anguillicaudatus -we did not observe hatching in weatherfish at temperatures above 24 °C (due to lethal impact -see Discussion below)). Size of newly hatched larvae seems to be considerably influenced by parental attributes (Wootton, 1990;Panagiotaki and Geffen, 1992;Kamler, 2005), or water conditions (Keckeis et al, 1996;Prokes et al, 1998;Schiemer et al, 2003). We observed a significant decrease of the total length of newly hatched larvae (our data are c. 15% lower on average) compared to the figures presented by Grieb (1937), Kryzanovskij (1949), Kotlyarevskaja (1967) or Kostomarova (1975), probably caused by smaller egg size (observed during stripping -see Discussion above).…”

“…Temperature is considered one of the most important ones, affecting development and growth (Penaz et al, 1983;Kamler et al, 1998;Green and Fisher, 2004), morphometric features plasticity (Stouracova et al, 1988;Penaz et al, 1989), maximum swimming speed (Green and Fisher, 2004) or sex determination (Conover and Kynard, 1981). Many of the recent studies focused on early development of fishes arised to predict population dynamics and life requests of the various species for the intents of fisheries management (Keckeis et al, 1996;Kamler et al, 1998;Klimogianni et al, 2004;Jordaan et al, 2006). Therefore a comprehension of temperature effect on the early fish ontogeny is crucial in process of understanding of fish egg and early ontogenetic stages distribution, dynamics and mechanisms of adaptation (Klimogianni et al, 2004) to the fluctuating environmental conditions in the floodplain area (Ward, 1998;Pekarik et al, 2008).…”

“…Therefore a successful reproduction and a high level of survival of early ontogenetic stages are the key events for fish recruitment and fish population dynamics (Kamler, 1992;Schiemer et al, 2003). Fish early life history can be affected by many biotic or abiotic factors such as temperature, concentration of dissolved oxygen (Kotlyarevskaja, 1967;Keckeis et al, 1996;Bohlen, 2003), pH (Prokes et al, 1998), water current (Schiemer et al, 2003) or salinity (Bohlen, 1999a). Temperature is considered one of the most important ones, affecting development and growth (Penaz et al, 1983;Kamler et al, 1998;Green and Fisher, 2004), morphometric features plasticity (Stouracova et al, 1988;Penaz et al, 1989), maximum swimming speed (Green and Fisher, 2004) or sex determination (Conover and Kynard, 1981).…”

The evolutionary puzzle of egg size, oxygenation and parental care in aquatic environments

“…[78,79] [4,79]. Yet, given that 40% DO is comparatively low for natural seagrass meadows, and the exposure in our experiment was considerably longer than what is common in nature, this result shows that S. typhle is able to cope with brooding also at reduced O 2 levels.…”

Effects of hypoxia and organic enrichment on the coastal marine environment

“…The boreal Solea solea, a bottomliving flatfish shows levels of metabolic response similar to those of Mudskippers. Keckeis et al (1996) showed that reduced oxygen (10% air saturation) increased mortality and decreased hatching success in nase Chondrostoma nasus. (Rosenberg 1972).…”