Featured Elasmobranch- Narrow-Nose Chimaera
Category : Featured Elasmobranch
Harriotta raleighana Goode and Bean, 1895
Family Rhinochimaeridae (Long-nose chimaeras)
Identification: A long-nose chimaera with a compressed, somewhat elongate body tapering to a narrow tail. Snout moderately long, narrow, slightly flattened with a blunt-edge, often bent upwards. First dorsal fin tall, height greater than twice the height of second dorsal fin, with a straight, serrated spine; spine as tall as or taller than first dorsal fin; second dorsal fin long and low, base more than twice the length of pelvic fin. Pectoral fins broad and short, apices reaching beyond pelvic fin origin. Anal fin absent. Upper caudal fin lobe base shorter than lower lobe base; lobes similar in height; origin of lower lobe about opposite to insertion of second dorsal fin; caudal filament long; upper caudal margin without tubercles. Beak-like tooth plates ridged with hypermineralized tritors on surface. Adult males with a small frontal tenaculum and paired prepelvic tenaculum with large spines. Colour a uniform chocolate brown with darker fin edges.
Size:This species can grow up to 120 cm total length. Females are typically larger than males. Size a maturity is estimated at ~35 cm body length (BDL) for females and ~25 to 30 cm BDL for males. Average size at birth is 13 cm.
Distribution: Eastern North Pacific off of California and Baja California. Elsewhere, widespread with a global distribution in the North and South Atlantic, eastern Indian (off southern Australia), and western Pacific Ocean. Harriotta raleighana seems to be most common in the northern Atlantic, northwest Pacific and southwest Pacific.
Habitat: A deepwater species on continental slopes, found on or near the bottom at 360-2,000 m depth. Adults and juveniles may occupy different habitats like other chimaeras; however, little information exists on this species.
Biology: Reproduction is oviparous, likely laying two egg cases, one from each oviduct, at a time. However, nothing is known of reproduction and spawning in this species. Diet consists mainly of polychaetes, amphipods, mollusks, and crabs. Sediment was also found in the digestive tract suggesting an association with the seafloor. Squid beaks have also been observed, suggesting that this species is also capable of consuming more pelagic prey.
General interest: Not targeted in commercial fisheries but caught as bycatch in deepwater commercial trawl fisheries. Bycatch data is only available from the South Tasman Rise Trawl Fishery (STRF). The STRF data shows that H. raleighana is only a negligible bycatch component, and only a small proportion is retained. Increases in deepwater fisheries could pose a threat to future populations. This species is listed as Least Concern under the IUCN Red List of Threatened Species because it is fairly abundant with no immediate threats.
By Jenny Kemper
Pacific Shark Research Center
Moss Landing Marine Laboratories
8272 Moss Landing Road
Moss Landing, CA 95039