Shovelnose Guitarfish, Rhinobatos productus
Range: from San Francisco Bay to the Gulf of California
Ambush predators, Shovelnose Guitarfish hide in the sand while waiting for prey such as flatfish and crabs
Shovelnose Guitarfish use San Francisco Bay as a nursery ground to pup their young – up to 28 at a time.
The International Union for Conservation of Nature (IUCN) Red List notes the Shovelnose Guitarfish as “near threatened,” due to commercial fishing in Baja and the Gulf of California.
The bottom-dwelling animal is also often collected accidently as bycatch by shrimp and other fishermen.
Other man-made threats include pollution and dredging of shallow water bays and estuaries, the animal’s nursery grounds.
The Shovelnose Guitarfish has swum in waters ranging from San Francisco Bay to the Gulf of California for more than 100 million years.
The head of a Shovelnose Guitarfish resembles that of a ray or skate, with its long, pointed snout and a spade-shaped disc that is longer than it is wide. The head portion of the animal leads to a long tail, with two shark-like dorsal fins.
“Shovelnose Guitarfish represent an evolutionary offshoot between sharks and rays,” says Michael Grassmann, Senior Biologist at Aquarium of the Bay.
It could be said that Shovelnose Guitarfish are masters at the cord of “be-flat,” as they use their sand coloring to help them camouflage and bury into the sand. An ambush predator, the animal hides in the sand and waits for prey such as flatfish and crabs to cross its path. Its shovel-like rostrum or nose also helps it dig into the sand to find and eat worms, clams and other shellfish.
Female Shovelnose Guitarfish are particularly abundant in San Francisco Bay in the spring, where females outnumber males 53:1. Females come into the Bay and other estuaries before males arrive, to give birth to their young after an 11-12 month gestation or pregnancy period, and utilize the Bay’s shallow waters and sandy bottom as an ideal nursery ground. Females can give birth to as many as 28 pups.