Tag Archive: ELASMOBRANCHES: Cartilaginous fishes


TAXONOMY
Kingdom: Animalia
Phylum: Chordata
Class: Elasmobranchii (sharks and rays)
Subclass: elasmobranchii (No swim bladders, five to seven pairs of gill clefts opening individually to the exterior, rigid dorsal fins, and small placid scales).
Order: Carcharhiniformes (Ground sharks)
Family: Triakidae (Houndsharks are distinguished by possessing two large spineless dorsal fins, an anal fin, and oval eyes with nictitating eyelids. They are small to medium in size, ranging from 37 centimetres (15 in) to 220 centimetres (7.2 ft).

Genus/species: Triakis semifasciata

GENERAL CHARACTERISTICS: Grey to bronze-grey upper body with dark saddles and dots and a light ventral (bottom) surface. Short, broadly rounded snout. First dorsal fin is moderately large and its origin is over the pectoral fins inner margins. Second dorsal fin is nearly as large as the first one. Anal fin much smaller than the second dorsal fin. Pectoral fins broadly triangular. Max length : 198 cm (78 in).

Leopard Shark 2959038532_163d96da28_o

DISTRIBUTION/HABITAT: Common from Oregon state to Baja California,Mexico. Prefers sandy and rock-strewn substrate near rocky reefs. Most commonly in enclosed muddy bays, including estuaries and lagoons, typically at less than 3.7 m or 13 ft depth, but ranges to 91m or 300 ft.

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DIET IN WILD: Fishes (especially northern midshipman, sanddab, shiner perch, bat rays and smoothhounds), siphons of clams, crustaceans such as crabs and shrimp. Feeds heavily on fish eggs (herring, jacksmelt and topsmelt) attached to rocks and plants.

 The leopard shark captures prey by expanding its buccal cavity to create a suction force, which is facilitated by its labial cartilages swinging forward to form the mouth into a tube. Simultaneously, the shark protrudes its jaws forward to grip the prey between its teeth.

REPRODUCTION: Ovoviviparous. Litters 4–29. Young average 21 cm or 8 in at birth.

PREDATORS: Can live to at least 30 years. These good eating sharks are a very popular as a sport “fish.” Also preyed upon by other sharks.

Leopard Shark 8415453774_b665c7a08e_o

IUCN Least Concern

REMARKS: In San Francisco Bay, leopard sharks tend to remain in the Bay throughout the year, with some emigration during fall and winter. Not dangerous.

Fossils of leopard sharks have been discovered in deposits dated to more than 1,000,000 years old in southern California.

References

Peterson Field Guides, Pacific Coast Fishes, Eschmeyer and Hearld 1983

WordPress Shortlink http://wp.me/p1DZ4b-Yt

flickr https://www.flickr.com/photos/cas_docents/26397788159/in/album-72157608359804936/

fishbase www.fishbase.org/summary/2543

Ferry-Graham, L.A. (1998). “Effects of prey size and mobility on prey-capture kinematics in leopard sharks Triakis semifasciata” (PDF). Journal of Experimental Biology. 201 (16): 2433–2444. PMID 9679105.

Probably More Than You Want To Know About The Fishes Of The Pacific Coast, Milton Love 1996 Really Big Press p 60-61

TAXONOMY
Kingdom: Animalia
Phylum: Chordata
Class: Chondrichthyes
Subclass: Elasmobranchii
Order: Myliobatiformes
Family:Dasyatidae Family: Dasyatidae  Whiptail Stingrays; whip-like tails, which are much longer than the disc and lack dorsaland caudal fins. They also have one or more venomous spines near the base of the tail.

Genus/species: Dasyatis kuhlii

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GENERAL/CHARACTERISTICS: Angular disc. Dorsal color reddish-brown to olive drab with blue spots and smaller black spots, ventral side white. Tail with black and white bands is about as long as the body and usually has one stinging spine.

Maximum disc width: 50 cm (20 inches).

DISTRIBUTION/ HABITAT: Tropical Indo-West Pacific from the Red Sea east to the Philippines, Japan, and south to Australia. Found on sandy bottoms near coral and rocky reefs, from intertidal zone to 50 m (160 feet). Moves onto reef flats and into shallow lagoon waters at high tide.

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DIET IN THE WILD: Crabs and shrimp, also small fishes.

REPRODUCTION: Ovoviviparous; eggs retained in the female’s body; embryos receive nourishment from a yolk sac.

REMARKS: The Bluespotted Whiptail Stingray is venomous tail can deliver a painful wound. Like many other rays that wound humans, it usually stings only when inadvertently stepped on: it is difficult to see in turbid waters, especially when covered by sand with only the eyes visible.

References

California Academy of Sciences Reef Lagoon 2016

Ron’s WordPress shortlink  http://wp.me/p1DZ4b-YD

Ron’s flickr https://www.flickr.com/photos/cas_docents/5035114327/in/album-72157627919810858/

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