Scombrolabrax heterolepis Roule 1921

Scombrolabrax heterolepis Roule, 1921.

(Plate 1)

Longfin escolar, Black mackerel (English); Grilo-Preto (Portuguese, Brazil); Escolarín (Spanish, Spain).

On December 11, 2008, a small “gempylid” was caught by the TAMAR. The fish was caught 10 miles off Praia do Forte, (12º39´911”S; 37º54´302”W), Mata de São João, Bahia, Brazil, at 350 meters, with an electric reel, circle carbon steel hooks n. 12/0, 0.60 multifilament line, 0 1 kg sinker, and sardines (Sardinella spp.) as bait. It was a mature female which measured 239 mm SL. A photograph was taken and the fish preserved. Eleven other specimens were collected off Bahia and Espírito Santo in 2000, in an oceanographic survey aboard the French oceanographic research vessel Thalassa, to provide data to the Brazilian Program REVIZEE; the specimens are deposited at the MNRJ and were also examined by us. The meristic and morphometric data of all specimens examined, and that of selected literature, are displayed in Table 1.A–B.

Counts Roule (1921) Grey (1960) Fujii (1983) Cervigón (1996) Present Study Number of specimens 1 1 5 1 12 Dorsal fin spines and rays XII + I, 14 XII + I, 14 or 15 XII + I, 14–15 XII + I, 14 XII + I, 14–15 Anal fin spines and rays 14 or 15* II, 18 III, 16–18 III, 15 III,15–17 Pectoral fin rays 17 18 18–19 20 18 Lateral line scales 48–50 44–46 46–50 46 47–50 Lower gill rakers - 4 5-6 6 4–6

*: No spines mentioned.

McEachran & Fechhelm* Grey Cervigón Present Study (2005) (1960) (1996)

Number of specimens No mentioned 1 1 12

Head Length 34–35 34 34 30–34

Snout Length 0 9–11 0 9 0 8 0 9–10

Eye diameter, horizontal 0 9–10 10 11 0 8–11

Upper jaw length 16–17 16 15 13–15

Depth 24–25 24 29 22–24

Predorsal length 40–43 40 -- 38–39

Preanal length -- 68 -- 67–73

Pectoral fin length 30–36 35 36 31–37

Pelvic fin length 14–15 13 14 10 –13

2nd. dorsal fin base -- 16 -- 15–18

Anal fin base -- 19 -- 19–22

* No original data; data of several authors, including juveniles and larvae.

Diagnostic characters. Based on examined specimens and literature (Roule, 1921; Grey, 1960; Bond & Uyeno, 1980; Fujii, 1983; Nakamura, 1991; Cervigón, 1996; Nakamura & Parin, 2002; McEachran & Fechhelm, 2005) (Table 1.A & B). Our data wide the range of some counts and body proportions.

Body moderately elongate and compressed; head large, the interorbital region flat; eye very large, its diameter almost as long as the conical snout; mouth large, terminal, the upper jaw protractile, the lower projecting slightly beyond the upper; teeth in upper jaw in a row of small to moderate, compressed canines, with one or two very large, stout canines on either side of symphysis; teeth of lower jaw larger than those of upper, but none large canine present; first gill arch lower limb with 4 or 6 well developed denticulate gill rakers, one of them at the angle, and the upper limb with about 10 clusters of minute spines; opercle with two flat spines on posterior border. Two dorsal fins, the first with 12 spines and almost continuous with the second that has 1 spine and 14 or 15 soft rays; base of first dorsal fin almost twice the base of the second; anal fin with 2 or 3 spines and 15–18 soft rays, opposite and similar to second dorsal fin; caudal fin forked, moderately small; pectoral fin very long with 17–19 rays and almost reaches the anal fin origin; pelvic fin below origin of pectoral fin. Scales cycloid, irregular in size and shape and very deciduous; lateral line high on body, running close to the dorsal profile, ending slightly before the end of the second dorsal fin, and with 44–50 large, not deciduous scales. Vertebrae 30, 13 precaudal and 17 caudal. The gas bladder of adult specimens has bubblellike evaginations that fit into large lateral swellings with hollows (bullae) of the 5th to 12th vertebral parapophyses, a unique character among fishes. Color dark brown to grayish brown, the fins darker and the mouth lining black. Grows to about 30 cm SL.

Range. Atlantic, Pacific and Indian Oceans, in tropical and subtropical waters between 100 and 1,374 m of depth. According to several authors (e.g. McEachran & Fechhelm, 2005; Froese & Pauly, 2010) it wouldn´t occur in the Eastern Pacific and Southeastern Atlantic, but its presence there is well documented off the west coast of South America, at about 21o S and 80o W, and with a sample from Easter Island deposited at the Museo Nacional de Historia Natural de Chile (MNHNC P. 6415) (Melendez et al., 1993; Parin, 1986; Parin et al. 1997; Evseenko at al. 2004). In the Atlantic, it has been collected at sites very close to the African coast as MCZ 84369 (20o2´S and 6o59´W) and RUSI 48874 (off West Coast, SE Atlantic, Cape Province, South Africa), and probably also occurs in the southeastern Atlantic as well (http://collections.mcz.harvard.edu/Fish/ FishSearch.htm and Anonymous, 2000-A).

In the Western Atlantic it occurs from Canada to, at least, southern Bahia, in Brazil, including the Gulf of Mexico, Bermuda, the Bahamas, Caribbean, Lesser Antilles, Venezuela, French Guiana and Suriname (Coad, 2008; McEachran & Fechhelm, 2005; Costa et al., 2007; Fujii, 1983; Cervigón, 1996; Nakamura & Parin, 2002; Smith-Vaniz et al.., 1999).

Previous records from the Southwestern Atlantic. According to the ISH collection (Anonymous, 2000- B), the MCZ collection (http://collections.mcz.harvard.edu/Fish/FishSearch.htm) and Costa et al.. (2007), several specimens of the longfin escolar were collected off the Brazilian Coast since 1966. No work dealing with it had ever being published other than simple listing of the species and not formerly reporting it from the area and widening its range. Costa et al. (2007) report the capture of the specimens deposited at the MNRJ, from the Abrolhos Bank, off Bahia coast, between 922 and 1374 m, and list them amongst one of the most abundant species (Scombrolabrax “heterurus” in the text), a novelty for the adults elsewhere in the world. Parin et al., 1995, reported this species from the Rio Grande Rise.

Nomenclature note. Several authors consider the year of Roule´s description as 1922 (e.g. Grey, 1960; Potthoff et al.., 1981; Fujii, 1983; Parin, 1986 and 1990; Melendez et al.., 1993; Santos et al.., 1997; Richards, 2006) while others consider 1921 (Boschung, 1992; Smith-Vaniz et al.., 1999; McEachran & Fechhelm, 2005; Froese & Pauly, 2010). The very first description of the species comes in 1921 followed in the next year by another article, in a different journal (see References). So the correct date for the first description is 1921, not 1922.

Proposed Brazilian name. “Grilo-preto”, meaning “black cricket” in Portuguese. This name is adopted by the local fishermen due to its color and morphological resemblance with the Gempylidae “Grilo-branco” (white cricket), Neopinnula americana (Grey, 1953), another uncommon, silvery-white fish, collected at their main research area, Praia do Forte, Bahia.

Biology data. Habitat and depth. The specimen was caught at 350 m depth, and about 100–150 m from the ocean floor. It is a mesopelagic and benthopelagic species that inhabits the open ocean and the outer shelf and slope areas as well as underwater rises (Parin, 1990; Cervigón, 1996; Boschung, 1992; Parin et al., 1997; Evseenko at al., 2004). The capture of the species at 1,374 m reported by Costa et al. (2007) represents a new depth record.

Diet. Examining the stomach contents of Praia do Forte´s specimen we found that it preyed recently on fishes, cephalopods, and crustaceans, but the remains were not identifiable. The same diet items were already reported by Parin (1990). The stomach contents weighted 0.61g and in it we also found four Nematoda parasites.

Reproduction and spawning season. The specimen from Praia do Forte was a ripe female. Egg diameter was between 0.23 and 0.31 mm and we estimated about 220/ 250,000 in both ovaries that were full and had about the same size (9,000 mm 3) and weight (4.86 g). According to Potthoff et al. (1980), the “spawning probably occurs throughout the species range and the year”, because the larvae examined by them from the Atlantic Ocean were collected from February to April and from July to December.