OBSERVATION OF UNDESCRIBED BATHYRAJA SP. IN THE EAST OF NEW ZEALAND (South Pacific)
Natacha ERDYAU & Sergio-Gabriel NAHK
Summary: Presentation of a skate from Bathyraja genus captured around 2500 m depth east of New Zealand in 2007. A second one has been living photographed in 2009, confirming that it’s a not yet described abyssal species, and taxon Bathyraja transpicia Erdyau & Nahk, 2009 was proposed by authors.
Keywords: Rajidae, Bathyraja, new species, abyssal benthos, New Zealand
Methods: During the private exploration campaign using deep sea winch "Aotearoa deep sea", which took place on board of the fishing vessel "Moana Explorer" from 7 to 25 April 2007 in New Zealand, located on the slope off Wharanui (North-eastern South Island), at an average depth between 2,000 and 2,600 m, the different species of fish caught were identified and photographed each time. We have presented the most significant catch in an earlier publication (Erdyau & Nahk, 2007) which some have been preserved to integrate the collection of the Canterbury Museum. However, we have seen in the photo archive of the expedition one skate that we inappropriately identified as a juvenile specimen of Bathyraja abyssicola (Gilbert, 1896). Unfortunately we didn’t take it on collection, and it appears, after careful examination of photographs, that this individual differs from the species currently known.
This is an adult specimen of 16cm length, caught aboard the “Moana Explorer” on 12/04/2007, on station CH27 at 2467 m depth ; 42 ° 9 '47'' south / 176 ° 57 '12'' east (Fig. 2).
In a second research conducted in 2009 on the stations listed two years ago, we took some digital photographies at great depth. The private campaign, entitled "Deep Sea Aotearoa 2" took place aboard the vessel "Moana Explorer" from 12 to 18 November 2009 in New Zealand, on stations CH16 to CH9, at a depth between 2100 and 2450 m. Its primary objective was to collect information on species listed above, including photographs of fish in their environment. Several photos of a Bathyraja sp. have been made, showing a phenotype that confirms his relationship with the specimen caught in 2007.
This is an specimen of about 18 cm long, photographed from the "Moana Explorer" on 17/11/2009, station CH14 at 2231 m depth, 42 ° 30 '22'' south / 177 ° 37' 39''east (Fig. 3).
Identification: The absence of spines on the disc, the general shape of the rostrum and body push us to classify this species in the genus Bathyraja Ishiyama, 1958. There are four known species of this genus in New Zealand waters: B. asperula Garrick & Paul, 1974 ; B. richardsoni (Garrick, 1961) ; B. shuntovi Dolganov, 1985 ; B. spinifera (Garrick & Paul, 1974) ( Fig. 1 ).
It is now evident that the two specimens observed during surveys at sea are none of these species and does not constitute juvenile of them. Given the distribution of other members of the genus Bathyraja in the world and the morphological features observed, this is probably an undescribed species.