What is Elasmobranch?

Elasmobranch or Elasmobranchii is a group of cartilaginous fish comprised of shark, ray, and skate species. Closely related,  chimaera forms another group called Holocephali in which their skeleton also made of cartilage, just like the Elasmobranch. These cartilaginous fish differ from their relative, the Actinopterygii, which comprised of true bony fishes.

How to Identify Elasmobranchs?

Every Elasmobranch species have their own unique characteristics. Some can be easily differentiated, while some are difficult. However it is quite easy to differentiate between shark, ray and skate, and chimaera. 

  • Shark can be distinguished from ray and skate through their gill slits position. Shark’s gill slits are located on the side of their body just behind their eyes
  • Ray and skate’s gill slits are located on the underside of their body (ventral).

This key characteristic is an important differentiator as some shark species resemble ray and skate, and vice versa. Meanwhile, chimaera can be recognized in a glance due to their unique morphology.

Blacktip Shark (Carcharhinus limbatus)
(source: pixabay)

Spotted Eagle Ray (Aetobatus narinari)
(source: pixabay)

Pale Chimaera (Hydrolagus pallidus)
(source: ifremer)

There are identification guides and books that you can use to identify elasmobranchs 

The following are identification guides and books recommended by Elasmobranch Project Indonesia:

White et al. (2006) – Economically Important Sharks & Rays of Indonesia  
Identifying Sharks and Rays: A Guide for NSW Commercial Fishers 
Jabado (2019) – Wedgefishes and Giant Guitarfishes: A Guide to Species Identification 
Manta Trust – Field Guide to the Identifiation of Mobulid Rays (Mobulidae): Indo-West Pacific
Manta Trust – Field Identification Guide of the Prebranchial Appendages (Gill Plates) of Mobulid Rays for Law Enforcement and Trade Monitoring Applications
Manta Trust – Photo Identification Guide: Gill Rakers of Manta and Mobula Rays