Environment: milieu / climate zone / depth range / distribution range
Marine; brackish; reef-associated; depth range 0 - 130 m (Ref. 43278), usually 1 - 35 m (Ref. 40849). Subtropical; 44°N - 35°S, 122°W - 10°E (Ref. 247)
Length at first maturity / Size / Weight / Age
Maturity: Lm ?, range 230 - 240 cm
Max length : 430 cm TL male/unsexed; (Ref. 96339); common length : 304 cm TL male/unsexed; (Ref. 247); max. published weight: 109.6 kg (Ref. 40637); max. reported age: 25 years (Ref. 72467)
Morphology | Morphometrics
(total): 0. Moderately long barbels, nasoral grooves present but no perinasal grooves, mouth well in front of eyes, spiracles minute, precaudal tail shorter than head and body, dorsal fins broadly rounded (the first much larger than the second and anal fins), caudal fin moderately long, over 1/4 of total length, yellow-brown to grey-brown in color, with or without small dark spots and obscure dorsal saddle markings (Ref. 247). Head blunt, mouth inferior, pair of conspicuous barbels between nostrils (Ref. 26938).
Found on continental and insular shelves. Solitary (Ref. 26340) and sluggish fish, often encountered lying on the bottom (Ref. 9987). Nocturnal, feeding on bottom invertebrates such as spiny lobsters, shrimps, crabs, sea urchins, squids, octopi, snails and bivalves, and fishes like catfishes, mullets, puffers and stingrays. Ovoviviparous with 21 to 28 young in a litter (Ref. 9987, 43278). Kept in captivity for researches. May attack humans if they are molested or stepped upon accidentally. Edible, but mainly valued for its hide, which makes extremely tough and durable leather (Ref. 9987). Common over shallow sand flats, in channels, and around coral reefs; young may be found among prop roots of red mangroves (Ref. 26938).
Ovoviviparous, with 21 to 28 young in a litter. Development of young in the uterus being sustained by a large supply of yolk. Females give birth in late spring and summer in waters off Florida. During courtship, a pair sometimes a triplet of adults engaged in synchronized parallel swimming. While on it, the male may grab one of the female's pectoral fins with his mouth which induces the female to pivot 90° and roll on her back on the bottom. Then the male inserts a clasper in her vent, and then roll on his back beside the female. Pair may break apart and depart rapidly after copulation or the male may remain motionless on the subtrate as if recovering from the mating bout (Ref. 49562). Not all attempts of males to copulate with a female nurse shark result in successful fertilization, females may employ avoidance by 'pivotting and rolling' to escape from male attention (Ref. 49562). Or females may 'lie on back' and rest motionless and rigidly on the substrate (Ref. 51113, 49562). On the contrary, females send signals of readiness to copulate with males by arching their body toward their male partner and cupping the pelvic fin (Ref. 51126, 49562). Male nurse sharks may mate with many females over several weeks (polygyny) and vice versa (polyandry) (Ref. 49562). Also Ref. 205.
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 1 - Hexanchiformes to Lamniformes. FAO Fish. Synop. 125(4/1):1-249. Rome, FAO. (Ref. 247)
IUCN Red List Status (Ref. 120744)
CITES (Ref. 115941)
Threat to humans
Traumatogenic (Ref. 4690)
Fisheries: minor commercial; aquarium: public aquariums
Estimates of some properties based on models
Preferred temperature (Ref. 115969
): 22.3 - 28, mean 25.5 (based on 798 cells).
Phylogenetic diversity index (Ref. 82805
= 0.8125 [Uniqueness, from 0.5 = low to 2.0 = high].
Bayesian length-weight: a=0.00417 (0.00157 - 0.01110), b=3.08 (2.85 - 3.31), in cm Total Length, based on LWR estimates for this (Sub)family-body shape (Ref. 93245
Trophic Level (Ref. 69278
): 4.2 ±0.2 se; Based on diet studies.
Resilience (Ref. 69278
): Low, minimum population doubling time 4.5 - 14 years (K=0.14; tmax=25; Fec=21-28).
Vulnerability (Ref. 59153
): Very high vulnerability (81 of 100) .