Measurements were made of the surface areas (As) of the skin and gills of larval and juvenile walleye Stizostedion vitreum with a body mass (M) of between 2mg (1 day post hatch) and 2.3g (98 days post hatch). The skin, with a relative surface area (As/M) of approximately 8500mm2g-1, accounted for more than 99.9% of the total surface area (skin + gills) at 1 day post hatch. The relative area of the skin decreased as fish grew at an allometric rate of b-1=-0.32±0.01 (mean ± s.e.m., where b-1 is the specific-mass exponent in the allometric equation YxM-1=aMb-1, in which Y is surface area and a is a constant). The relative surface area of the gills (filaments + lamellae) increased in a hyperbolic fashion from very low levels (approximately 5mm2g-1) at 1 day post hatch to reach a maximum of approximately 1100mm2g-1 at a body mass of approximately 200mg. Thereafter, relative gill area declined at an allometric rate of b-1=-0.19±0.10 (mean ± s.e.m.). Gill area, because it declined at a slower relative rate, finally exceeded skin area at a body mass of approximately 700mg. The relative surface area of the skin and gills combined (total surface area) decreased at a more-or-less constant allometric rate of b-1=-0.21±0.01 (mean ± s.e.m.) throughout the experimental period. On the basis of the allometric rates of expansion, the structural capacity to supply oxygen (b-1=-0.19; total gill area, this study) and metabolic demand for oxygen (b-1~-0.13; mean literature value for routine and resting metabolism) appear to remain fairly closely matched in postlarval walleye (>300mg). The two parameters do not display the same degree of concordance during larval development. In larvae, total respiratory surface area declines on a mass-specific basis at roughly the same rate (b-1=-0.21) as gill area does in older fish but, unlike in older fish, metabolic demand for oxygen does not change (b-1~0.0). This results in a progressive decline in effective respiratory surface area (As/M.O2) but does not affect O2 uptake, probably because larvae are so small that surface area is not the limiting factor in gas exchange. Analysis of data from the literature suggests that surface area typically becomes limiting at a body mass of approximately 100mg. The major function of gills in smaller larvae (<100mg) appears to involve ionoregulation or related aspects of acid­base balance rather than respiratory gas exchange.
In the field: an interview with Harald Wolf
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In our new Conversation, Harald Wolf talks about his fieldwork experiences working with desert ants in Tunisia to understand their navigation.
Propose a new Workshop
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Our Workshops bring together leading experts and early-career researchers from a range of scientific backgrounds. Applications are now open to propose Workshops for 2024, one of which will be held in a Global South country.
Julian Dow steps down and John Terblanche joins the JEB team
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After 15 years with the journal, Julian Dow from University of Glasgow, UK, is stepping down as a Monitoring Editor. We wish Julian all the best for the future and welcome John Terblanche, Stellenbosch University, South Africa, who is joining the team. Julian talks about his long association with The Company of Biologists and the journal and John tells us about his life and career in this News article.
The capture of crude oil droplets by filter feeders at high and low Reynolds numbers
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Researchers from the University of Montreal, Canada, reveal how tiny filter feeding barnacles and Daphnia entrap and consume minute droplets of crude oil, introducing the pollutant at the bottom of the food chain.
Patterns and processes in amphibious fish
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In their Review, Keegan Lutek, Cassandra Donatelli and Emily Standen discuss the biomechanics and neural control of terrestrial locomotion in amphibious fish. They explore how locomotor mode depends on body shape, physical constraints and phylogeny.
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