First record of Neocyttus helgae ( Pisces : Oreosomatidae ) on the slope off Galicia ( Northwest Spain ) *

Fishes from the family Oreosomatidae, also known as “oreos” (Myers, 1960), are widely distributed throughout the Southern Hemisphere, and are abundant in the deep waters of the shelf and slope in the southeastern Atlantic, south of Australia, the Tasman Sea and New Zealand (Myers, 1960; Lloris, 1986; James et al., 1988). In the waters off southeastern Australia and around New Zealand four species of oreos (Allocyttus verrucosus, Allocyttus niger, Neocyttus rhomboidalis and Pseudocyttus maculatus) are commonly caught as a by-catch to the fishery of the orange roughy, Hoplostethus atlanticus. Until recently, oreos were mostly discarded, but they are currently considered to be a commercial species (Lyle et al., 1992; Lyle and Smith, 1997). There are few records of Oreosomatidae species found in the temperate waters of the Northern Hemisphere (Myers, 1960; Karrer, 1990). In the Northeast Atlantic the family is represented by two species: Allocyttus verrucosus and Neocyttus helgae (Karrer, 1986; Du Buit and Quéro, 1993). This contribution records the catch of a specimen of Neocyttus helgae (Holt and Byrne 1908) in the waters of the Galician continental slope (Northwest Spain). The fact that only a few specimens of this species have been caught in the Northeast Atlantic and that it has not been recorded to date as a member of the ichthyologic fauna of the Iberian Peninsula should warrant special interest. SCI. MAR., 63 (2): 177-180 SCIENTIA MARINA 1999


INTRODUCTION
Fishes from the family Oreosomatidae, also known as "oreos" (Myers, 1960), are widely distributed throughout the Southern Hemisphere, and are abundant in the deep waters of the shelf and slope in the southeastern Atlantic, south of Australia, the Tasman Sea and New Zealand (Myers, 1960;Lloris, 1986;James et al., 1988).In the waters off southeastern Australia and around New Zealand four species of oreos (Allocyttus verrucosus, Allocyttus niger, Neocyttus rhomboidalis and Pseudocyttus maculatus) are commonly caught as a by-catch to the fishery of the orange roughy, Hoplostethus atlanticus.Until recently, oreos were mostly discarded, but they are currently considered to be a commercial species (Lyle et al., 1992;Lyle and Smith, 1997).There are few records of Oreosomatidae species found in the temperate waters of the Northern Hemisphere (Myers, 1960;Karrer, 1990).In the Northeast Atlantic the family is represented by two species: Allocyttus verrucosus and Neocyttus helgae (Karrer, 1986;Du Buit and Quéro, 1993).
This contribution records the catch of a specimen of Neocyttus helgae (Holt and Byrne 1908) in the waters of the Galician continental slope (Northwest Spain).The fact that only a few specimens of this species have been caught in the Northeast Atlantic and that it has not been recorded to date as a member of the ichthyologic fauna of the Iberian Peninsula should warrant special interest.

MATERIAL AND METHODS
A specimen of Neocyttus helgae (Fig. 1) was caught in the waters of the continental slope off northern Galicia in April 1997 by the fishing vessel "Sarridal" based at the port of Cedeira (A Coruña, Spain).The specimen was caught using large mesh gill nets, at a depth of 900 m, in the fishing ground known as "As Paredes", at a geographical position of 44º 12' N, 8º 18' W (Fig. 2).The specimen was transferred to the collection of the Centro Oceanográfico of the Instituto Español de Oceanografía in A Coruña.
Morphometric measurements were taken and the following structures were counted: gill rakers of the first gill arch, lateral line scales, and spines and rays of the fins.

RESULTS AND DISCUSSION
In the Family Oreosomatidae, juveniles and adults are extremely different in body form.All species of Oreosomatidae are assumed to undergo a pelagic pre-juvenile Oreosoma stage, which is characterized by a deep body having conical protuberances along the sides (Myers, 1960;Karrer, 1986;James et al., 1988).The present specimen shows adult characteristics.The following external details primarily describe the adult of N. helgae: very deep body, compressed with a rhomboid shape; and a concave predorsal profile.The head surface covered with asperities, and consequently much rougher and more granulated than the remainder of the body.All fin spines are strong.
The first anal and second dorsal spines are the longest and strongest, and have fine longitudinal grooves.The soft dorsal and anal fin rays have small lateral spinules.The spine of the pelvic fins exceeds the origin of anal fin.The body coloration is deep brown; and the fin and gill membranes, as well as the mouth parts, are blue-gray.
There are few records of Neocyttus helgae from the Northeast Atlantic.Apart from the holotype of N. helgae (Holt and Byrne, 1908) from off the Irish coast, the other record of the species described was caught north of Madeira.Although it was first described as Crassispinus granulosus Maul (1948) and later as Neocyttus rhomboidalis, Alburquerque (1954)(1955)(1956), reported differences between the sample from Madeira and other N. rhomboidalis sam-ples described by other authors and suggested a revision of the specimen, that finally was identified as N. helgae by Wheeler (1973).Both records are the only ones listed in the review of the family Oreosomatidae in the Northeast Atlantic (Karrer, 1986).They are also the only ones which were studied morphometrically.However, Quéro et al. (1985) reported the first record of a specimen of Neocyttus helgae in the Bay of Biscay.Later, Quéro et al. (1993) reported the catch of several specimens between a depth of 1000 and 1100 m from the banks of "Petite Sole" and "La Chapelle", but they did not present morphometric or meristic data.In addition to these references to the species, it is important to note that Bakes et al. (1995), in a comparative study of the biochemical composition of several species of oreos in Australian waters, also mentioned the use of three specimens of Neocyttus helgae, caught in 1993 in Atlantic waters around the Faroe Islands.
Morphometric and meristic characteristics for the present specimen as well as the data reported from the specimens from Ireland (Holt and Byrne, 1908) and Madeira (Maul, 1948) are given in Table 1.There is a narrow range of variability in the data provided.However, the specimen from Galicia shows the largest length of the second dorsal and first anal fin spines.The live weight of the specimen was 0.225 kg.
NEOCYTTUS HELGAE ON THE SLOPE OFF GALICIA 179 The biology of Neocyttus helgae is not known.Living at great depths, it shows habits possibly corresponding to a midwater species, which would make it inaccessible to the gears used by commercial fisheries.The exploration and expansion of fishing activity to the deep zones of the slope, which has been occurring in several areas of the Northeast Atlantic, will likely bring to light new catches of fishes that have been uncommon up to now.Species such as the one reported here, and which are thought to be rare or solitary, may prove to be abundant at certain depths.
FIG. 2. -Location of the capture of Neocyttus helgae in Galician waters.

TABLE 1 .
-Comparison of measurements and counts for specimens of Neocyttus helgae.