Salt-water Musicians?

Here's a critter from deep in the archives (if not so deep in the sea).

This is a Brown Guitarfish (Rhinobatos schlegelii), from the Denver Aquarium. While he looks like a cross between a stingray and a shark, he's actually considered to be in the family Rhinobatidae, in the Order Rajiformes. (That is, he's a ray, but closer to the skates than the stingrays.) He's found in the western Pacific, from Korea to Australia. 1 There are 50 species of these guys, found throughout the warmer oceans of the world. 2  Mostly they hang out in shallow coastal waters, eating snails, clams, and other bottom-dwellers.

I haven't had much luck finding studies that focused on this one, although Fishbase does state that it's a fine eating species, but other species, such as the Common Guitarfish (R. rhinobatos) from the Eastern Atlantic and Mediterannean, and the Shovelnose Guitarfish (R. productus) from the west coast of the US and Mexico, are quite well-studied, from distributions to reproductive biology 3,4,5,6 to genetic variation. 7

That last study found something quite interesting to my mind -- unrecognized genetic differentiation between fish from the west coast of Baja California and those from the Gulf of California just to the east. The authors didn't go so far as to claim the two forms were separate species, but they did point out that this sort of variation should be a concern when we're contemplating conservation or management measures. This species isn't endangered, but several others are, including the Common Guitarfish. (Brown and Shovelnose are listed as data-deficient by the IUCN).8

While the Brown and Shovelnose aren't considered endangered, they are both heavily fished, so all of this study, including the ongoing taxonomic work, are very important, if we want to keep them around.


1) http://www.fishbase.org/summary/Rhinobatos-schlegelii.html

2) http://en.wikipedia.org/wiki/Guitarfish

3) Enajjar, S., Bradai, M. N., & Bouain, A. (2008). New data on the reproductive biology of the common guitarfish of the Gulf of Gabes (southern Tunisia, central Mediterranean). Journal of the Marine Biological Association of the UK, 88(05), 1063-1068.

4) Ismen, A., Yıgın, C., & Ismen, P. (2007). Age, growth, reproductive biology and feed of the common guitarfish (< i> Rhinobatos rhinobatos</i> Linnaeus, 1758) in İskenderun Bay, the eastern Mediterranean Sea. Fisheries Research, 84(2), 263-269.

 

5) Abdel-Aziz, S. H., Khalil, A. N., & Abdel-Maguid, S. A. (1993). Reproductive cycle of the common guitarfish, Rhinobatos rhinobatos (Linnaeus, 1758), in Alexandria waters, Mediterranean Sea. Marine and Freshwater Research, 44(3), 507-517.

 

6) Sandoval-Castillo, J., Rocha-Olivares, A., Villavicencio-Garayzar, C., & Balart, E. (2004). Cryptic isolation of Gulf of California shovelnose guitarfish evidenced by mitochondrial DNA. Marine Biology, 145(5), 983-988.

 

7) Márquez-Farías, J. F. (2007). Reproductive biology of shovelnose guitarfish Rhinobatos productus from the eastern Gulf of California México. Marine biology, 151(4), 1445-1454.

8) The IUCN Red List of Threatened Species. Version 2014.2. <www.iucnredlist.org>. Downloaded on 16 October 2014.