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Rhizoprionodon acutus (Rüppell, 1837)

Milk shark
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Rhizoprionodon acutus   AquaMaps   Data sources: GBIF OBIS
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Classification / Names Common names | Synonyms | Catalog of Fishes(genus, species) | ITIS | CoL | WoRMS | Cloffa

Elasmobranchii (sharks and rays) > Carcharhiniformes (Ground sharks) > Carcharhinidae (Requiem sharks)
Etymology: Rhizoprionodon: rhiza (Gr.), root; prion (Gr.) saw; odon (Gr.), tooth, referring to teeth with serrated (saw-like) bases, or roots [replacement name for Rhizoprion Ogilby 1915, preoccupied by Rhizoprion Jourdan 1861 in mammals]. (See ETYFish);  acutus: Latin for sharp or pointed, probably referring to narrow, pointed snout. (See ETYFish).
More on author: Rüppell.

Environment: milieu / climate zone / depth range / distribution range Ecology

Marine; freshwater; brackish; benthopelagic; amphidromous (Ref. 51243); depth range 1 - 200 m (Ref. 244). Tropical; 41°N - 30°S, 27°W - 156°E

Distribution Countries | FAO areas | Ecosystems | Occurrences | Point map | Introductions | Faunafri

Eastern Atlantic: Madeira and Mauritania to Angola (Ref. 244). Indo-West Pacific: Persian Gulf (Ref. 68964), Red Sea and East Africa to Indonesia, north to Japan, south to Australia. Also reported from Gulf of Taranto in Mediterranean Sea (Ref. 231).

Length at first maturity / Size / Weight / Age

Maturity: Lm 75.0, range 70 - 80 cm
Max length : 175 cm TL male/unsexed; (Ref. 12693); 80.8 cm TL (female); common length : 110 cm TL male/unsexed; (Ref. 47737); max. published weight: 5.0 kg (Ref. 40637); max. reported age: 8 years (Ref. 244)

Short description Identification keys | Morphology | Morphometrics

Dorsal spines (total): 0; Anal spines: 0. A small shark with a long, narrow, snout, big eyes without notches, long labial furrows, and oblique-cusped teeth which may be smooth-edged or weakly serrated; 2nd dorsal fin small, low and behind larger anal fin; no interdorsal ridge (Ref. 5578). Grey or grey-brown above, white below (Ref. 5578). Dorsal and anal fins with dusky or blackish edges, fins slightly darker than back (Ref. 9997).

Biology     Glossary (e.g. epibenthic)

Found on continental shelves, often on sandy beaches and rarely in estuaries (Ref. 244). Reported to enter freshwater and recorded several times from Cambodia as far upstream as the Great Lake (Ref. 12693). Occurs near the surface in shallow waters (Ref. 12693). Feeds mainly on small pelagic and benthic bony fishes, also cephalopods and other invertebrates (Ref. 244). Viviparous (Ref. 50449). Utilized fresh and possibly dried salted for human consumption and for fishmeal (Ref. 9997). The 178 cm specimen recorded off Africa is possibly based on some other species (Ref. 9997).

Life cycle and mating behavior Maturities | Reproduction | Spawnings | Egg(s) | Fecundities | Larvae

Distinct pairing with embrace (Ref. 205). Viviparous, with a yolk-sac placenta; 2 to 8 in a litter (Ref. 9997), usually 2 to 5 after a gestation period of ~ 12 months; no seasonality in the reproductive cycle (Ref.58048). Size at birth between 25 and 39 cm.

Main reference Upload your references | References | Coordinator : Compagno, Leonard J.V. | Collaborators

Compagno, L.J.V., 1984. FAO Species Catalogue. Vol. 4. Sharks of the world. An annotated and illustrated catalogue of shark species known to date. Part 2 - Carcharhiniformes. FAO Fish. Synop. 125(4/2):251-655. Rome: FAO. (Ref. 244)

IUCN Red List Status (Ref. 130435)

  Vulnerable (VU) (A2bd); Date assessed: 04 February 2020

CITES


CMS (Ref. 116361)

Not Evaluated

Threat to humans

  Harmless (Ref. 244)





Human uses

Fisheries: commercial; gamefish: yes
FAO - Publication: search | FishSource | Sea Around Us

More information

Trophic ecology
Food items
Diet compositions
Food consumptions
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Predators
Ecology
Ecology
Population dynamics
Growths
Max. ages / sizes
Length-weight rel.
Length-length rel.
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Abundances
Life cycle
Reproduction
Maturities
Fecundities
Spawnings
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Egg(s)
Egg developments
Larvae
Larval dynamics
Anatomy
Gill areas
Brains
Otoliths
Physiology
Body compositions
Nutrients
Oxygen consumptions
Swimming type
Swimming speeds
Visual pigment(s)
Fish sounds
Diseases / Parasites
Toxicities (LC50s)
Genetics
Genetics
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Human related
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Stamps, coins, misc.
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Internet sources

AFORO (otoliths) | Alien/Invasive Species database | Aquatic Commons | BHL | Cloffa | BOLDSystems | Websites from users | Check FishWatcher | CISTI | Catalog of Fishes: genus, species | DiscoverLife | ECOTOX | FAO - Publication: search | Faunafri | Fishipedia | Fishtrace | GenBank: genome, nucleotide | GloBI | Google Books | Google Scholar | Google | IGFA World Record | MitoFish | National databases | Otolith Atlas of Taiwan Fishes | PubMed | Reef Life Survey | Socotra Atlas | Tree of Life | Wikipedia: Go, Search | World Records Freshwater Fishing | Zoological Record

Estimates based on models

Preferred temperature (Ref. 123201): 19.6 - 28.5, mean 26.9 °C (based on 1463 cells).
Phylogenetic diversity index (Ref. 82804):  PD50 = 0.5078   [Uniqueness, from 0.5 = low to 2.0 = high].
Bayesian length-weight: a=0.00339 (0.00273 - 0.00421), b=3.08 (3.04 - 3.12), in cm total length, based on LWR estimates for this species (Ref. 93245).
Trophic level (Ref. 69278):  4.3   ±0.4 se; based on diet studies.
Generation time: 5.5 ( na - na) years. Estimated as median ln(3)/K based on 1 growth studies.
Resilience (Ref. 120179):  Very Low, minimum population doubling time more than 14 years (K=0.2-0.6; Fec=1).
Fishing Vulnerability (Ref. 59153):  High vulnerability (61 of 100).
Price category (Ref. 80766):   Medium.
Nutrients (Ref. 124155):  Calcium = 16.4 [2.3, 90.2] mg/100g; Iron = 0.575 [0.146, 1.652] mg/100g; Protein = 21.2 [18.2, 23.5] %; Omega3 = 0.198 [0.082, 0.472] g/100g; Selenium = 58 [16, 171] μg/100g; VitaminA = 20.7 [7.9, 53.8] μg/100g; Zinc = 0.698 [0.324, 1.318] mg/100g (wet weight);