Understanding gas bubble trauma in an era of hydropower expansion: how do fish compensate at depth?

Peña

et al. 2021

Fishes

Alterations in fish developmental trajectories occur in response to genetic and environmental changes, especially during sensitive periods of development (critical windows). Embryos and larvae of Atractosteus tropicus were used as a model to study fish survival, growth, and development as a function of temperature (28 °C control, 33 °C, and 36 °C), salinity (0.0 ppt control, 4.0 ppt, and 6.0 ppt), and air saturation (control ~95% air saturation, hypoxia ~30% air saturation, and hyperoxia ~117% air saturation) during three developmental periods: (1) fertilization to hatch, (2) day 1 to day 6 post hatch (dph), and (3) 7 to 12 dph. Elevated temperature, hypoxia, and hyperoxia decreased survival during incubation, and salinity at 2 and 3 dph. Growth increased in embryos incubated at elevated temperature, at higher salinity, and in hyperoxia but decreased in hypoxia. Changes in development occurred as alterations in the timing of hatching, yolk depletion, acceptance of exogenous feeding, free swimming, and snout shape change, especially at high temperature and hypoxia. Our results suggest identifiable critical windows of development in the early ontogeny of A. tropicus and contribute to the knowledge of fish larval ecology and the interactions of individuals × stressors × time of exposure.

Section: Critical Windows For Survivalmentioning

confidence: 78%

Survival, Growth, and Development in the Early Stages of the Tropical Gar Atractosteus tropicus: Developmental Critical Windows and the Influence of Temperature, Salinity, and Oxygen Availability

Peña

et al. 2021

Fishes

“…This is misleading, however, because there is evidence that fish that die of GBT generally have bubbles in the gills (e.g. Antcliffe et al., 2002; Bentley, Dawley, & Newcomb, 1976; Pleizier et al., 2020). It should also be noted that sampling intervals varied greatly in both the time to bubbles in the gills dataset (mean 15.8h ± 6 SE) and the mortality dataset (e.g.…”

Section: Discussionmentioning

confidence: 99%

A meta‐analysis of gas bubble trauma in fish

et al. 2020

Self Cite

There is currently a worldwide proliferation of dams, with 59 000 hydroelectric dams over 15 m high registered with the International Commission On Large Dams (2018). Furthermore, there are an additional 3,700 hydroelectric dams over 1 megawatt (MW) planned or under construction as of 2015 (Zarfl, Lumsdon, Berlekamp, Tydecks, & Tockner, 2015). Once these dams are constructed, the number of large, free-flowing rivers worldwide will be further reduced by 21% (Zarfl et al., 2015). These numbers do not account for the proliferation of small hydroelectric dams; Couto and Olden (2018) estimate that there exist over 82,000 small hydropower dams worldwide (≤10 MW or based on each country's definition of small hydropower dams). Currently, only 37% of rivers longer than 1,000 kilometres are free-flowing over their entire length (Grill et al., 2019). Most new dams are being built in countries with developing and emerging economies (Zarfl et al., 2015), where important benefits include electricity generation, control of water supply, low flow

“…0.3-0.9 m depth) of the cages in the Lake Evangervatnet. When compensating for pressure (Pleizier et al, 2020), an average TDG of 110.2 and 108.3% in the surface water provides compensation to ca 107 and 105% TDG at 0.3 m water depth and 105 and 103% TDG at 0.9 m depth at the bottom of the cages. In the Lake Evangervatnet, an average TDG of 107.2% did not cause mortality.…”

Section: Discussionmentioning

confidence: 99%

“…For example, radio tagged rainbow trout, cutthroat trout (O. clarkii Richardson, 1836), brown trout (Salmo trutta Linnaeus, 1758) and bull trout (Salvelinus confluentus Suckley, 1859) occupy median depths from 1.3 to 2 m in a river with 101% to 135% TDG (Weitkamp & Sullivan, 2003). The depth preference for fish is important because hydrostatic pressure protects fish from GBD by ca 10% per meter depth (Pleizier et al, 2020). Fish can compensate by swimming deeper, thereby reducing harmful effects from TDG compared to fish confined to shallow water (Ebel, 1969;Weitkamp, 1976;Heggberget, 1984;Cao et al, 2019;Pleizier et al, 2020).…”

Section: Discussionmentioning

confidence: 99%

“…The depth preference for fish is important because hydrostatic pressure protects fish from GBD by ca 10% per meter depth (Pleizier et al, 2020). Fish can compensate by swimming deeper, thereby reducing harmful effects from TDG compared to fish confined to shallow water (Ebel, 1969;Weitkamp, 1976;Heggberget, 1984;Cao et al, 2019;Pleizier et al, 2020). This was demonstrated by Antcliffe et al (2002), who exposed juvenile rainbow trout to 122% TDG for 96 h in tanks of differing water depth.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Acute effects of gas supersaturation on Atlantic salmon smolt in two Norwegian rivers

et al. 2020

Total dissolved gas (TDG) supersaturation downstream of hydropower plants may cause gas bubble disease (GBD) and harmful effects in fish. Little is known about tolerance levels of TDG supersaturation on Atlantic salmon (Salmo salar Linnaeus, 1758) in natural rivers. The present study investigated the effects of TDG supersaturation on the survival of Atlantic salmon smolts at two field sites in Norway. Here, we kept smolts in cages at increasing distances from hydropower plants known to cause TDG supersaturation and at control sites. We recorded fish mortality and examined for GBD using a stereo microscope. Mortality and symptoms of GBD commenced in fish exposed to an average of 108.3% TDG (maximum 111.0%, water depth 0.55 m) for 2 days. Significant differences in time before mortality at the control sites and test sites commenced at 110.2% TDG (maximum 111.8%) for 3 days. The study indicates that Atlantic salmon may be more vulnerable to TDG supersaturation than Pacific salmonids, which are considered at risk when the TDG is above 110%. In addition, the study provides important data to link effects caused by TDG in the laboratory and in the field.