Thermal requirements for growth, survival and aerobic performance of weatherfish larvae Misgurnus fossilis

Abstract

Thermal requirements of larval weatherfish Misgurnus fossilis were investigated in terms of growth, survival and aerobic performance. Growth and survival of M. fossilis larvae acclimated to five temperatures (11, 15, 19, 23 and 27° C) were measured over 25 days. In the upper temperature treatments (19, 23 and 27° C), survival of larvae was stable throughout the entire rearing period (>75%), whereas 11 and 15° C resulted in severe declines in survival (to <10%). Growth of larvae (expressed as dry mass and total length) was highest at 19 and 23° C, but significantly decreased at 27° C. Routine metabolic rate of 3 days post-hatch larvae was estimated as oxygen consumption rate (ṀO ) during acute exposure (30 min to 1 h) to seven temperatures (11, 15, 19, 23, 27, 31 and 35° C). Larval oxygen uptake increased with each consecutive temperature step from 11 to 27° C, until a plateau was reached at temperatures >27° C. All larvae of the 35° C regime, however, died within the ṀO measurement period. M. fossilis larvae show greater than expected tolerance of high temperatures. On the other hand, low temperatures that are within the range of likely habitat conditions are critical because they might lead to high mortality rates when larvae are exposed over periods >10 days. These findings help to improve rearing conditions and to identify suitable waters for stocking and thus support the management of re-introduction activities for endangered M. fossilis.

First successful hybridization experiment between native European weatherfish (Misgurnus fossilis) and non-native Oriental weatherfish (M. anguillicaudatus) reveals no evidence for postzygotic barriers

“…Given the fact that VO2 values are generally highly variable and are mostly presented as logarithmically transformed values, we consider those values to correspond nicely. Our fish were too large and methods were too different for making meaningful comparisons with measurements on early larval European weatherfish by Schreiber et al (2017), or those for Oriental weatherfish by White et al (2017). We observed a negative trend in VO2 per gram wet mass with increasing body mass, which is a well -known pattern in the early ontogeny of larval and juvenile fish (Chabot et al 2016) and reflects lower weight-specific metabolic rates with increasing body mass as the scaling exponent between oxygen consumption and mass is typically lower than one (Clarke and Johnston 1999;Isaac and Carbone 2010).…”

Reintroduction and stock enhancement of European weatherfish (Misgurnus fossilis L.) in Rhineland-Palatinate and Hesse, Germany

“…Subsequently, individuals from different populations origin were maintained separately. Artificial propagation followed the procedure reported by Schreiber et al (2017b). In brief, males and females were isolated from each other, and water temperature was gradually increased to 18°C, before a gonadotropinreleasing hormone (GnRH) containing preparation (Ovopel, Unic-trade) was intramuscularly injected in two divided doses.…”

“…A good feasibility of weatherfish production was previously reported in several studies (Kouril et al, 1996;Demény et al, 2009). However, comprehensive investigations on the thermal requirements of weatherfish larvae carried out along with the program helped to increase their survival and growth rates during the rearing period (Schreiber et al, 2017b). This illustrates how scientific guidance of different steps in comparable conservation programs may improve the prospects and hence is explicitly recommended.…”

“…existing infrastructure). Moreover, as the program is part of a larger scientific project with additional investigations of other aspects than stocking activities (Schreiber et al, 2017a(Schreiber et al, , 2017b(Schreiber et al, , 2018, only approximations could be provided. Therefore, it has to be emphasized that additional costs that were excluded from the presented calculation (e.g.…”

Food resource partitioning between juvenile and mature weatherfish Misgurnus fossilis

“…In the case of weatherfish, these data are still largely lacking. There are few published studies on the biology of M. fossilis, with limited focus on threats and protection (Hartvich et al 2010;Freyhof and Brooks 2011;Schreiber et al 2018a), habitat preferences (Meyer and Hinrichs 2000;, reproduction (Geldhauser 1992;Adamkova-Stibranyiova et al 1999;Drozd et al 2009;Schreiber et al 2017a;Pyrzanowski et al 2021 in press), growth (Pyrzanowski et al 2020b), and morphology (Kotusz 1996).…”