Environment: milieu / climate zone / depth range / distribution range
Marine; freshwater; brackish; demersal; depth range 2 - 25 m (Ref. 55207), usually 2 - 6 m (Ref. 55207). Subtropical; 39°N - 17°N, 100°W - 75°W (Ref. 55207)
Western Atlantic: Chesapeake Bay to southern Florida in the USA and the Gulf of Mexico. Records from South America doubtful (Ref. 7251).
Length at first maturity / Size / Weight / Age
Maturity: Lm 22.0, range 22 - 23 cm
Max length : 61.0 cm WD male/unsexed; (Ref. 6902); common length : 27.0 cm WD male/unsexed; (Ref. 6902); common length :39 cm WD (female); max. published weight: 4.9 kg (Ref. 40637)
Morphology | Morphometrics
Prominent triangular snout. Broadly rounded outer corners of disc. Upper surface brown or yellowish brown, paler toward margins of disc. Lower surface white (Ref. 6902). Few scapular spines. Middorsal row of spines present, but few on tail beyond pelvic fins (Ref. 7251).
Adults inhabit coastal waters, including estuaries and lagoons (Ref. 12951) and ascend rivers (Ref. 12951). They feed on tube anemones, polychaete worms, small crustaceans, clams, and serpent stars (Ref. 12951). Ovoviviparous (Ref. 50449). Parturition occurs in July and August (Ref. 27549). Litters of 2-3 pups; gestation 4 months (Ref. 114953).
Life cycle and mating behavior
Maturity | Reproduction | Spawning | Eggs | Fecundity | Larvae
Exhibit ovoviparity (aplacental viviparity), with embryos feeding initially on yolk, then receiving additional nourishment from the mother by indirect absorption of uterine fluid enriched with mucus, fat or protein through specialised structures (Ref. 50449). Distinct pairing with embrace (Ref. 205).
Robins, C.R. and G.C. Ray, 1986. A field guide to Atlantic coast fishes of North America. Houghton Mifflin Company, Boston, U.S.A. 354 p. (Ref. 7251)
IUCN Red List Status (Ref. 126983)
Threat to humans
Fisheries: of no interest
Estimates based on models
Preferred temperature (Ref. 123201
): 23.2 - 27, mean 25.5 °C (based on 272 cells).
Phylogenetic diversity index (Ref. 82804
= 0.5039 [Uniqueness, from 0.5 = low to 2.0 = high].
Bayesian length-weight: a=0.00575 (0.00235 - 0.01406), b=3.07 (2.87 - 3.27), in cm total length, based on LWR estimates for this (Sub)family-body shape (Ref. 93245
Trophic level (Ref. 69278
): 3.5 ±0.42 se; based on food items.
Resilience (Ref. 120179
): Very Low, minimum population doubling time more than 14 years (K=0.26-0.31; Fec assumed <10).
Fishing Vulnerability (Ref. 59153
): Very high vulnerability (90 of 100).
Nutrients (Ref. 124155
): Calcium = 15.8 [2.1, 309.7] mg/100g ; Iron = 0.739 [0.068, 8.595] mg/100g ; Protein = 22.3 [20.0, 24.4] % ; Omega3 = 0.199 [0.062, 0.591] g/100g ; Selenium = 14.8 [2.7, 68.8] μg/100g ; VitaminA = 6.9 [0.6, 69.4] μg/100g ; Zinc = 0.726 [0.053, 8.530] mg/100g (wet weight); based on nutrient studies.