Influence of Oxygen Concentration on the Growth of Juvenile Largemouth Bass

Abstract

Experiments are reported on the influence of nearly constant dissolved oxygen concentrations, both below and above the air-saturation level, and of wide diurnal fluctuations of oxygen concentration on the appetite, growth, and food conversion efficiency of juvenile largemouth bass, Micropterus salmoides (Lacépède). The experimental apparatus used was designed to provide constant flows of water at 26 C and with controlled oxygen content through 12-gal (45-liter) bottles each containing 10 test fish. The fish were fed unrestricted rations of small, live earthworms throughout the six experiments, whose duration was usually 15 days.The growth rates and food consumption rates of the bass increased markedly with increase of the constant oxygen concentrations to levels near the air-saturation level, and declined with further increase of oxygen concentrations. Gross food conversion efficiencies were considerably reduced only at concentrations well below 4 mg/liter.The growth of bass subjected alternately to low and higher oxygen concentrations for either equal or unequal portions of each 24-hr day was markedly impaired. It was almost always less than that which presumably would have occurred had the fish been held at a constant concentration equal to the mean, either arithmetic or geometric, of the higher and lower concentrations to which the fish had been exposed.

Responses to hypoxia of plaice, Pleuronectes platessa, and dab, Limanda limanda, in the south-east Kattegat: distribution and growth

“…Our laboratory experiments showed that growth was initially reduced at 50% O 2-saturation in dab and 30% O 2-saturation in plaice Even if some adaptation to low oxygen (30% O 2-saturation) occurred during the second part of the experiment, a significant overall reduction in growth was found for both species during a 20 d period Converting length into weight using the relationships described in Pihl (1989b) indicates that the normoxic growth rates for plaice and dab in our experiments are in general agreement with those (1 5-3 0% weight d -1 ) measured in the SE Kattegat Studies on other fish species, especially freshwater species, have shown° (Herrmann et al 1962, Stewart et al 1967, Adelman & Smith 1970, Andrews et al 1973, Brett & Blackburn 1981, Pedersen 1987 Our field data suggests that parts of the plaice and dab stocks could be exposed to hypoxia during at least 20 days periods, and for up to 3 months each year to moderate hypoxia Comparable exposures in the laboratory study resulted in reduced growth It is likely that repeated and increasing physiological stress from hypoxia during autumn would result in a long-term decrease in population mean length However other factors may also affect the length distribution of dab and plaice during the study period The most possible factors are variation in recruitment and availability of food resources Recruitment of plaice and dab have been investigated in shallow water in the adjacent Laholm Bay during the period 1980 to 1986 During this period no significant trend in recruitment strength, settling time or mean size of 0-or 1 groups were found for the two species (Pihl 1989b) In addition, the number of small-size recruiting individuals was insignificant in our study due to size-selection of the gear, and age-and size-dependent depth distribution of both species Juveniles of plaice and dab spend their first 2 years at water depths less than 10 m and join the parental stock during start of maturity the third year (Pihl 1989b) Thus, the observed reduction in mean length of the adult plaice and dab stocks may not be due to specific patterns in recruitment of juveniles Benthic infauna is the main food for plaice and dab in the SE Kattegat (Bagge et al ', Degel & Gislason,5 Pihl 1994) The total biomass of benthic infauna has shown a significant increasing trend over the last decades in areas without severe hypoxic events (Pearson et al 1985, Josefson 1990 …”

Response of rock-lobster populations in the Benguela ecosystem to environmental change — a hypothesis

“…Similar effects of low oxygen concentration on growth rates have been recorded by several authors for a number of fish species (e.g. Adelman and Smith 1970, Fisher 1963, Swift 1963, Stewart et al 1967). …”

Assessment of Dissolved Oxygen Mitigation at Hydropower Dams Using an Integrated Hydrodynamic/Water Quality/Fish Growth Model

“…Too few experimental studies on how fish respond to such conditions have been done to develop a consensus on a standard response. Stewart et al (1967) and Whitworth (1968) both found that fish exposed to intermittently low and high DO had lower growth rates than fish exposed to the mean DO concentration. A review of the subject by Brett (1979) concludes that exposure to sub-critical DO levels for only a portion of the day is enough to depress the growth rate to that comparable with the constant low DO concentration.…”