Skates (Rajidae) in Norwegian waters

Skates are a vulnerable group of fish with low reproduction with few offspring, and are subject to overfishing and by-catch. In Norwegian waters skates are not well known and they have proved to be difficult to identify correctly. DNA barcoding should be of good help to identify specimens correctly. That was the aim to test and find out when our project was planned.

Bycatch of Dipturus oxyrinchus from a fish trawl in the Trondheimsfjord. Photo Jarle Mork/NTNU.
Bycatch of Dipturus oxyrinchus from a fish trawl in the Trondheimsfjord. Photo Jarle Mork/NTNU.

A Master of Science project by Arve Lynghammar (2009) aimed at DNA barcoding of known skate species from Norwegian waters, and to produce an identification key. The project showed that cryptic species were present, especially related to Dipturus batis, and also suggested that there are unresolved challenges related to species delimitation and phylogeny of the group.

DNA barcoding proved to be a very valuable tool to identify specimens present in the North-East Atlantic, which will be important due to challenges in identification based on morphological characters. It has also been suggested that the starry ray (Amblyraja radiata) is not a part of a species complex but is represented by connected populations across the North Atlantic. During the project a quantity of specimens were examined and Arve gained broad knowledge of morphological variation of the different species present in North-East Atlantic species.

Arve Lynghammar has continued our initially project as a PhD student and later researcher at the University of Tromsø – the Arctic University. Arve earned his PhD in 2014.

Publications from the project:

Lynghammar A, Christiansen JS, Griffiths AM, Fevolden SE, Hop H, Bakken T. 2014. DNA barcoding of the northern Northeast Atlantic skates (Chondrichthyes: Rajiformes), with remarks on the widely distributed starry ray. Zoologica Scripta 43: 485-495. DOI: 10.1111/zsc.12064

Griffiths A, Sims D, Johnson A, Lynghammar A, McHugh M, Bakken T, Genner M. 2011. Levels of connectivity between longnose skate (Dipturus oxyrinchus) in the Mediterranean Sea and the north-eastern Atlantic Ocean. Conservation Genetics 12(2): 577-582. DOI: 10.1007/s10592-010-0127-3

Griffiths AM, Sims DW, Cotterell SP, El Nagar A, Ellis JR, Lynghammar A, McHugh M, Neat FC, Pade NG, Queiroz N, Serra-Pereira B, Rapp T, Wearmouth VJ, Genner MJ. 2010. Molecular markers reveal spatially segregated cryptic species in a critically endangered fish, the common skate (Dipturus batis). Proceedings of the Royal Society B: Biological Sciences: 1497-1503. DOI: 10.1098/rspb.2009.2111

Lynghammar A. 2009. Morphological characteristics and DNA barcoding of skates (Rajidae) in the Norwegian Economic Zone. Department of Biology. Trondheim: Norwegian University of Science and Technology. p 118.