Updated: Aug 7, 2018
During the spring and summer seasons, we see an increase of cartilaginous fish populations in the SF Bay. This week's creature is the shovelnose guitarfish
The shovelnose guitarfish (Rhinobatos productus) is a medium-sized guitarfish (a group of skates) that inhabits shallow coastal waters from San Francisco Bay, CA to the southern Gulf of California, Mexico. With a compressed body shape, this species inhabits sandy or muddy waters typically shallower than 39 feet, but has also been recorded at depths of up to 300 feet! Their ability to pump water over their gills allows them to hover above the seafloor to feed on a variety of prey that also dwells at the bottom.
Guitarfish exhibit an annual reproductive cycle, as females come during the spring and summer to give birth in shallow bays and estuaries to a single litter pair per year. Litters range from 1-16 pups, and gestation takes 4 to 5 months. Males arrive in late summer to mate, and then all individuals depart in the fall.
Reference and Resources
Shovelnose Guitarfish | Oceana https://oceana.org/marine-life/sharks-rays/shovelnose-guitarfish
Farrugia, T.J., Márquez-Farías, F., Freedman, R.M., Lowe, C.G, Smith, W.D. & Bizzarro, J.J. 2016. Pseudobatos productus. The IUCN Red List of Threatened Species 2016: e.T60171A104004394. http://dx.doi.org/10.2305/IUCN.UK.2016-3.RLTS.T60171A104004394.en. Downloaded on 22 June 2018.