Beringraja rhina explained

Beringraja rhina, commonly known as the longnose skate, is a species of skate in the family Rajidae from the northeast Pacific. It is found from the eastern Bering Sea and Alaska to Baja California and the Gulf of California. The longnose skate is found at depths of 9- and often deeper than the big skate.^{[1] [2]} The longnose skate has only recently been associated with the genus Beringraja, having been previously included in Raja until genetic evidence supported reclassification.^{[3] [4]} This issue has not be completely resolved and the scientific name "Raja rhina" is still in widespread use.^[1]

Description

The longnose skate has an elongated snout and deeply notched pelvic fins. Maximum size has been reported as 1.8m (05.9feet) in length.^[5] Maximum age has been estimated as 25 years in Gulf of Alaska^[6] and 26 years in British Columbia.^[7] The age estimates are based on counting growth bands in vertebrae, a method which has been validated using bomb radiocarbon.^[8]

Distribution and habitat

In a recent study published in August 2019, researchers found that this nearshore species tends to dwell in the upper continental slope in highly sedimented areas, and also in association with rock out crops, authigenic carbonate crust, and mixed substrate areas in depths between 200 and 929 m. Longnoses inhabited areas with 3–6 °C temperatures. This research came from the first long-scale, long-term assessment of skates in deepwater of the eastern North Pacific.^[9]

Reproduction

The longnose skates egg case is large and smooth, and has large webbed keels on its posterior and anterior margins. The egg case's maximum size is 15cm (06inches) long and 12cm (05inches) wide.

Notes and References

1. Web site: Raja rhina, Longnose skate : fisheries . Fishbase.org . 2016-07-20 . 2018-08-16.
2. Book: Stevenson . Duane E. . Orr . James W. . Hoff . Gerald R. . McEachran . John D. . Field Guide to Sharks, Skates, and Ratfish of Alaska . 2007 . Alaska Sea Grant College Program, University of Alaska Fairbanks . 978-1-56612-113-2.
3. Last, P. R., S. Weigmann and L. Yang 2016. Changes to the nomenclature of the skates (Chondrichthyes: Rajiformes). In: Last and Yearsley (eds.). Rays of the World: Supplementary Information. CSIRO Special Publication. 11-34.
4. Web site: Chondrichthyan Tree of Life . . 16 August 2018.
5. Stevenson. D. E.. 2004. Identification of Skates, Sculpins, and Smelts by Observers in North Pacific Groundfish Fisheries (2002-2003). NOAA Technical Memorandum. NMFS-AFSC-142.
6. Gburski. Christopher M.. Gaichas. Sarah K.. Kimura. Daniel K.. 2007-10-01. Age and growth of big skate (Raja binoculata) and longnose skate (R. rhina) in the Gulf of Alaska. Environmental Biology of Fishes. en. 80. 2. 337–349. 10.1007/s10641-007-9231-8. 25457468. 1573-5133.
7. McFarlane. G. A.. King. J. R.. 2006-05-01. Age and growth of big skate (Raja binoculata) and longnose skate (Raja rhina) in British Columbia waters. Fisheries Research. en. 78. 2. 169–178. 10.1016/j.fishres.2006.01.009. 0165-7836.
8. King. J. R.. Helser. T.. Gburski. C.. Ebert. D. A.. Cailliet. G.. Kastelle. C. R.. 2017-09-01. Bomb radiocarbon analyses validate and inform age determination of longnose skate (Raja rhina) and big skate (Beringraja binoculata) in the north Pacific Ocean. Fisheries Research. en. 193. 195–206. 10.1016/j.fishres.2017.04.004. 0165-7836. free.
9. Kuhnz . L.A. . Bizzarro . J.J. . Ebert . D.A. . In situ observations of deep-living skates in the eastern North Pacific . Deep Sea Research Part I: Oceanographic Research Papers . September 2019 . 152 . 103104 . 10.1016/j.dsr.2019.103104 . free .