Daggernose shark
A critically endangered shark with a distinctive elongated snout.
The daggernose shark (Carcharhinus oxyrhynchus) is a poorly understood requiem shark found in the warm, shallow coastal waters off northeastern South America, ranging from Trinidad down to northern Brazil. It sticks to murky, muddy environments like mangroves, estuaries, and river mouths, but cannot tolerate freshwater. This small shark, usually about 1.5 meters (4.9 feet) long, is easy to identify thanks to its unusually long, flat, pointed snout, very small eyes, and large, paddle-shaped pectoral fins.
It feeds mainly on small schooling fish. Females give birth to between two and eight live young every other year, timed to the rainy season, and they can shift their reproductive schedule by several months depending on conditions. Harmless to people, the daggernose shark is caught for its meat and as accidental bycatch in both small-scale and commercial fishing. Because it has a limited range and reproduces slowly, the International Union for Conservation of Nature has listed it as Critically Endangered after a steep population drop in recent years. As of 2023, fewer than 250 individuals are thought to remain, and the species may already be in reproductive collapse, which could lead to its extinction in the near future.
Quick Facts
- Genus
- Carcharhinus
- Species
- oxyrhynchus
Facts from the source article.
Lore & Background
The first scientific description of the daggernose shark, as Carcharias oxyrhynchus, was published by German biologists Johannes Peter Müller and Friedrich Gustav Jakob Henle in their 1839 Systematische Beschreibung der Plagiostomen. The specific epithet oxyrhynchus comes from the Greek oxys ('sharp' or 'pointed') and rhynchos ('nose'). In 1862, American ichthyologist Theodore Gill coined the genus Isogomphodon for this species, but it was later resurrected by shark authority Stewart Springer in 1950. A 2023 phylogenetic study found the daggernose shark to be deeply nested within the genus Carcharhinus, as the sister species to the smalltail shark (C. porosus), leading to its reclassification as Carcharhinus oxyrhynchus. An extinct apparent relative, †Carcharhinus acuarius, has been identified from the Middle Eocene of Germany, though this clashes with phylogenetic estimates dating the divergence of the daggernose and smalltail sharks to the Middle Miocene.
Reader's Guide
The daggernose shark is notable for its critically endangered status and steep population decline. It has declined over 90% over the past decade off Brazil, with similar declines likely elsewhere due to increasing fishing pressure. The current population is believed to be extremely low, with no more than 250 individuals believed to be in existence as of 2023. It may even be in reproductive collapse, in which case it will likely become extinct in the near future. The IUCN has urgently recommended the implementation of conservation schemes and the expansion of fishery monitoring for this species. The shark is caught for food and as bycatch in artisanal and commercial fisheries, comprising about one-tenth of the catch of a northern Brazil floating gillnet fishery targeting Serra Spanish mackerel and Acoupa weakfish. Its limited range and slow reproductive rate make it highly susceptible to overfishing. The daggernose shark is harmless to humans due to its small size and teeth.
Did You Know?
- The daggernose shark is capable of shifting the timing of its reproductive cycle by at least four months in response to environmental conditions.
- Its elongated snout and tiny eyes are likely adaptations to living in the muddy, sediment-laden waters produced by the plume of the Amazon River.
- Females give birth to litters of 2–8 pups every other year, following a year-long gestation period.
- The species was reclassified as Carcharhinus oxyrhynchus in 2023 based on phylogenetic evidence.
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