Adaptation to hypoxic environments; bearded gobies Sufflogobius bibarbatus in the Benguela upwelling ecosystem.
The oceans of the world are slowly losing oxygen, in part because of climate change and in part because of anthropogenic eutrophication. This deoxygenation affects marine organisms in species-specific ways. This paper reviews what is known on how hypoxia tolerant species respond to low dissolved oxygen, using the bearded goby Sufflogobius bibarbatus as a model system. This species is endemic to the Benguela upwelling ecosystem, where, off Namibia, 9000 km2 of the shelf is hypoxic. Here, the species is now considered central to ecosystem functioning and in recent decades it has sustained commercial fisheries. Unlike their predators, S. bibarbatus has strong anti-predator responses as they can remain alert and escape threats in anoxic and severely hypoxic waters and can cope with sulphide shocks. Populations display diel vertical migration and shuttle between suboxic seabed refugia during the day to more oxygenated waters higher up in the water column at night and whilst they may share the water column with predators they may reduce their predation risk by associating with jellyfish (Aequorea forskalea and Chrysaora fulgida). The spatial distribution of S. bibarbatus varies with changes in available oxygen and populations expand and contract with climate-induced changes in the distribution of hypoxic waters. This species has an unusual diet and plays an important role in ecosystem functioning. It is a batch-spawner, with a protracted spawning season. Remarkably, males display alternative reproductive tactics and reproduction can take place at oxygen levels <0·5 ml l-1 dissolved oxygen on the shelf break. Gaps in knowledge are identified and future works are proposed.
['Salvanes|A G V|AGV|', 'Gibbons|M J|MJ|']
D000064:Acclimatization D000222:Adaptation, Physiological D025041:Animal Migration D000818:Animals D057231:Climate Change D017753:Ecosystem D005260:Female D000860:Hypoxia D008297:Male D009276:Namibia D009792:Oceans and Seas D010100:Oxygen D010473:Perciformes D011235:Predatory Behavior D012098:Reproduction D012621:Seasons D012623:Seawater
hypoxia tolerance behaviour eastern boundary current life history