buoyancy
- Swim bladder morphology changes with female reproductive state in the mouth-brooding African cichlid Astatotilapia burtoni
Highlighted Article: Redistribution of gas between anterior and posterior chambers of a compartmentalized swim bladder allows mouth-brooding females to better regulate buoyancy and swimming posture during this extreme maternal care behavior.
- Physostomous channel catfish, Ictalurus punctatus, modify swimming mode and buoyancy based on flow conditions
Summary: Channel catfish adopted negative buoyancy in lentic environments, but maintained buoyancy closer to neutral in lotic environments to optimise their locomotion.
- Body density and diving gas volume of the northern bottlenose whale (Hyperoodon ampullatus)
Summary: Body density and diving gas volume, two important but poorly understood physiological characteristics of beaked whales, are revealed through analysis of hydrodynamic performance during glides.
- Does the physiology of chondrichthyan fishes constrain their distribution in the deep sea?
Summary: Chondrichthyan fishes (sharks, rays and chimaeras) are exceedingly rare or possibly absent at abyssal depths (>4000 m), unlike bony fishes. This Commentary discusses hypotheses implicating the unusual physiology of chondrichthyans as an explanation for their scarcity at great depths.
- Gas exchange and dive characteristics of the free-swimming backswimmer Anisops deanei
Highlighted Article: Exotic gas experiments and mathematical modelling show that backswimmers extend dive duration by extracting 20% of their O2 directly from the water.
- Mechanical challenges to freshwater residency in sharks and rays
Summary: The high negative buoyancy of elasmobranchs increases the cost of locomotion and may be responsible for the scarcity of sharks in fresh water.