Hypoxia and Sprint Swimming Performance of Juvenile Striped Bass,Morone saxatilis

Abstract

Annual hypoxia in the Chesapeake Bay has expanded to the point where Darwinian fitness of juvenile striped bass (Morone saxatilis) may depend on their ability to perform in low-oxygen environments. The locomotion they use in predator/prey dynamics relies primarily on white (type II) muscle that is powered by anaerobic metabolic pathways and has generally been thought to be immune to aquatic hypoxia. We tested the sprint performance of 15 juvenile striped bass twice under acute hypoxia (20% air saturation [AS]) 5 wk apart and once under normoxia (>85% AS) in between. Average sprint performance was lower under the first hypoxia exposure than in normoxia and increased in the second hypoxia test relative to the first. The rank order of individual sprint performance was significantly repeatable when comparing the two hypoxia tests but not when compared with sprint performance measured under normoxic conditions. The maximum sprint performance of each individual was also significantly repeatable within a given day. Thus, sprint performance of striped bass is reduced under hypoxia, is phenotypically plastic, and improves with repetitive hypoxia exposures but is unrelated to relative sprint performance under normoxia. Since energy to fuel a sprint comes from existing ATP and creatine phosphate stores, the decline in sprint performance probably reflects reduced function of a part of the reflex chain leading from detection of aversive stimuli to activation of the muscle used to power the escape response.

Lizards at the Peak: Physiological Plasticity Does Not Maintain Performance in Lizards Transplanted to High Altitude

“…Our results further support the use of sprint speed as proxy for individual performance capacity in this lizard species, as has been established in some fish species (e.g., Oufiero and Garland 2009). To our knowledge, this is the first study to establish the repeatability of sprint speed under hypoxic con- ditions in lizards, corroborating a recent study in striped bass (Morone saxatilis) that found individual consistency in swimming speed under hypoxic conditions (Kraskura and Nelson 2018). As we predicted based on previous work in a variety of taxa, lizards adjusted blood chemistry in response to high-altitude hypoxia (Storz 2007;Storz et al 2010).…”

Hypoxia alters vulnerability to capture and the potential for trait-based selection in a scaled-down trawl fishery

“…Under hypoxic conditions that restrict aerobic metabolism, fish may be forced to prioritize specific oxygen-consuming physiological processes. Voluntary swimming activity, for instance, may be limited under hypoxia (Schurmann and Steffensen, 1994; Kraskura and Nelson, 2018), as aerobic scope will be reduced (Richards, 2009). Importantly, reductions in swimming capacity with increasing hypoxia have been shown in several fish species of commercial importance, including cod Gadus morhua (Schurmann and Steffensen, 1994), dogfish Scyliorhinus canicula (Metcalfe and Butler, 1984) and sole Solea solea (Dalla Via et al , 1998).…”

“…The fact that fishing can occur in hypoxic areas is perhaps best reflected by the reported surges in capture where fishing and low oxygen co-occur (Gray, 1992; Breitburg, 2002). A possible explanation for this increase in catch is the constraining effect of hypoxia on fish locomotor or sensory physiology (Kraskura and Nelson, 2018), which may inhibit escape responses. Given that active fishing gears (e.g.…”

Hypoxia tolerance is unrelated to swimming metabolism of wild, juvenile striped bass (Morone saxatilis)

“…Yet, for active, pelagic fishes like striped bass, performance under hypoxia tolerance may be a more relevant metric (e.g. Kraskura and Nelson, 2018). HT also appears to be a highly plastic and contextdependent physiological trait in fishes and it varies substantially among individuals of the same size, age and species (Nelson et al, 2019;Nelson and Lipkey, 2015;Killen et al, 2016).…”