Merluccius Polli and M. Senegalensis (Merlucciidae) As First Records from the Canary Islands (North-Eastern Atlantic), SFI
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Ichthyological note Merluccius polli and M. senegalensis (Merlucciidae) as first records from the Canary Islands (north-eastern Atlantic), SFI © with morphology data Submitted: 9 Sep. 2019 Accepted: 12 Dec. 2019 Editor: R. Causse by J. Gustavo GONZÁLEZ-LORENZO (1), Raül TRIAY-PORTELLA (2), José F. GONZÁLEZ-JIMÉNEZ (1), Pablo MARTÍN-SOSA (1), Sebastián JIMÉNEZ (1) & José A. GONZÁLEZ* (2) Résumé. – Premier signalement de Merluccius polli et M. senega- MATERIAL AND METHODS lensis (Merlucciidae) aux îles Canaries (Atlantique nord-est), et données morphologiques. The material studied was caught in waters of the Canary Islands (Fig. 1). La capture d’un individu de Merluccius polli et d’un autre de M. senegalensis représente le premier signalement pour ces espè- Both standard and ichthyological meristic/morphometric meas- ces tropicales aux îles Canaries. Deux hypothèses principales peu- urements (in mm) were made following Hubbs and Lagler (1958) vent être proposées pour expliquer la présence des deux espèces de and Lloris et al. (2005); SL, standard length; TL, total length. Fin- merlu noir dans les eaux des Canaries : des individus errants ou rays and vertebral counts with their distinguishing features were l’expansion de l’aire de répartition naturelle des zones voisines. Ce travail contribue également à la connaissance des caractéristiques obtained from radiographs, using X-ray equipment model Top 10 morphologiques et méristiques des deux espèces, y compris la for- with an 80 KHz high-frequency generator. mule vertébrale et ses caractéristiques distinctives. The voucher specimens were deposited in the collections of the Tenerife Museum of Natural History (TFMC). The present work Key words. – Merlucciidae – Merluccius – Black hake – First records – Morphology – Canary Islands – North-eastern Atlantic. follows the best practice approach to prevent unverified and unveri- fiable “first records” as proposed by Belloet al. (2014). It is well known that Merluccius merluccius (Linnaeus, 1758) is the only merlucciid species recorded from the Canary Islands to date (e.g. Brito et al., 2002; Báez et al., 2019). The Spanish Institute of Oceanography (IEO) carried out a series of fishery monitoring surveys in the waters surrounding the Marine Reserve of the island of La Palma, between 2003 and 2012. Fish specimens thus collected were studied by the present authors, and a firstMerluccius specimen appeared to belong to a species not regularly occurring in the Canaries. Additionally, fish specimens caught by a small-scale fishery around the Canary Islands in 2004- 2006 were inspected by the former Canary Institute of Marine Sci- ences (ICCM) and among these specimens, another non-native Merluccius was found. After careful morphometric and meristic study by the authors, these two specimens turned to be Merluccius senegalensis and M. polli, respectively. Both non-indigenous specimens caught in Canary Islands waters were submitted to a detailed morphomet- ric and meristic study, which resulted in the identification of Mer- luccius senegalensis and M. polli, respectively. The present account records two merlucciid species for the first time from the Canaries. It also contributes to enrich the morpho- logical data (including their vertebral formulae and distinguishing features) and geographical distribution of these tropical West Afri- Figure 1. – The Canary Islands. Collection locations for the first records. : can species. Merluccius polli; ■: Merluccius senegalensis. (1) Instituto Español de Oceanografía, Centro Oceanográfico de Canarias, Calle Farola del Mar 22, Dársena Pesquera, 38180 Santa Cruz de Tenerife, Spain. [[email protected]] [[email protected]] [[email protected]] [[email protected]] (2) Ecología Marina Aplicada y Pesquerías, i-UNAT, Universidad de Las Palmas de Gran Canaria, Campus de Tafira, 35017 Las Palmas de Gran Canaria, Spain. [[email protected]] [[email protected]] * Corresponding author Cybium 2020, 44(1): 57-60. https://doi.org/10.26028/cybium/2020-441-007 Merluccius polli and M. senegalensis from the Canaries GONZÁLEZ -LORENZO ET AL . RESULTS of La Palma, 28°36’30”N-17º56’51”W, 476-570 m, cruise PexLa- Palma 2009, St. 32, 31 May 2009, horizontal bottom longline. Merluccius polli Cadenat, 1950 Morphology data. – Morphometrics, selected body proportions, Material examined. – TFMCBM-VP/01952, one maturing meristics and other distinguishing features of the Canary specimen female, 624 mm TL, 559 mm SL, off Playa Nueva, Tazacorte, West of M. polli studied are shown in Table I, and compared with data from the literature (Cohen et al., 1990; Lloris et al., 2005, 2016). Body propor- Table I. – Morphometrics, body proportions, counts and other features of Merluccius polli. tions, meristic data and other specific TFMCBM-VP/01952 features of this specimen agree in all Cohen et al. (1990) 624 mm TL respects with published data (Tab. I). Lloris et al. (2005, 2016) present study Its pectoral fin length almost reaches Morphometrics and body the lower limit of the species’ published mm in %SL in %HL in %SL in %HL proportions range, probably reflecting different Standard length 559 – – – – sizes of this fin: left fin nearly reach- ing the origin of the anal fin, but right Pectoral fin length (left) 97.2 17.4 – 17.7-21.8 – fin reaching it (Tab. I; usually reaching Pectoral fin length (right) 94.8 17.0 – 17.7-21.8 – the origin of anal fin, but not in large Pelvic fin length 73.5 13.2 – 13.0-16.7 – individuals, according to Cohen et al. Maximum body depth 64.3 11.5 – – – (1990)). Radiographs corroborate five Head length 145 26.0 – 24.8-29.1 – cervical vertebrae with three ribs on Snout length 51.6 9.2 35.5 – 30.2-35.9 each, as attributed to this species by Cohen et al. (1990) and Lloris et al. Upper jaw length 71.4 12.8 49.2 – 45.3-51.3 (2005) (Fig. 2; Tab. I). Eye diameter 26.2 4.7 18.0 – 16.4-21.8 Remarks. – A deep-water bathy- Inter-orbital width 36.7 6.6 25.3 – 24.1-28.0 demersal species, ranging from 50 to Pectoral fin tips reaching … Nearly reaching (left) / reaching (right) Usually reaching origin 1098 m depth, usually shallower than origin of anal fin of anal fin; not in large 550 m, living close to the bottom on individuals the continental shelf and slope (Mau- Meristics rin, 1963; Cohen et al., 1990; Lloris et First dorsal fin rays I + 10 I + 7 - 12 al., 2005; Manchih et al., 2018). Geo- Second dorsal fin rays 39 36-41 graphically, it is an eastern Atlantic spe- cies, distributed along the West African Anal fin rays 39 36-42 shelf and slope, from a locality between Pectoral fin rays 16 (left) / 15 (right) 14-17 Cape Juby (Atlantic Morocco) and Upper gill rakers (1st arch) 2 1-3 Cape Bojador (Western Sahara) (Mau- Lower gill rakers (1st arch) 8 7-9 rin, 1963; Manchih et al., 2018) and Total gill rakers (1st arch) 10 8-12 southward into southwest Africa near Cape Frio, Namibia, including the Cape Scales along lateral line ca. 116 98-127 Verde Islands (Reiner, 2005), ranging Total vertebrae 56 52-57 29°N-19°S, 19°W-15°E (Cohen et al., Cervical vertebrae 5 5 1990; Maurin, 1990; Lloris et al., 2005; Ribs on each cervical vertebrae 3 3 Manchih et al., 2018). At the northern Precaudal vertebrae 28 23-28 limit of its distribution area, this non- Caudal vertebrae 28 27-31 migratory species (Lloris et al., 2005) is only represented by a few large individ- Other distinguishing features uals (500-630 mm TL) living at depths Soft rays All branched greater than 500 m (Maurin, 1963). Scales on lacrimal Yes Dorsal surface of head Large and little depressed Caudal fin White-edged Figure 2. – Radiographs of M. polli from the Canary Islands (TFMCBM-VP/01952, maturing female, 624 mm TL). Insert: Detail of five cervical vertebrae. 58 Cybium 2020, 44(1) GONZÁLEZ -LORENZO ET AL . Merluccius polli and M. senegalensis from the Canaries Merluccius senegalensis Cadenat, 1950 with data from the literature (Svetovidov, 1986; Cohen et al., 1990; Material examined. – TFMCBM-VP/01449, one adult, 804 mm Lloris et al., 2005, 2016). Body proportions, meristic data and other TL, 756 mm SL, East of Roque del Este, North-East of Lanzarote, specific features of this specimen agree in all respects with those 29º16’N-13º20’W, 295 m, 12 Dec. 2004, handline. in the literature (Tab. II). In particular, the morphometric propor- Morphology data. – Morphometrics, selected body proportions, tion of snout length in %HL is slightly extended upward, while meristics and other distinguishing features of the Canary specimen eye diameter and inter-orbital width in %HL are slightly extend- ed downwards (Tab. II). The presently studied material slightly of M. senegalensis studied are shown in Table II, and compared extends the range of upper gill rakers on the first arch (3-4 in lit., this study, Table II. – Morphometrics, body proportions, counts and other features of Merluccius senegalensis. 5) (Tab. II). Radiographs corroborate Svetovidov (1986) six cervical vertebrae with four ribs on TFMCBM-VP/01449 Cohen et al. (1990) each, which is in agreement with Sve- 804 mm TL Lloris et al. (2005, tovidov (1986), Cohen et al. (1990) and Present study 2016) Lloris et al. (2005) (Fig. 3; Tab. II). Morphometrics and body proportions mm in %SL in %HL in %SL in %HL When fresh, the studied specimen Standard length 756 – – – – exhibited a characteristic olive green blotch (dark at its proximal end) at the Pectoral fin length 130 17.2 – 16.5-21.3 – base of pectoral fins. A fishing captain Pelvic fin length 114 15.1 – 13.1-16.9 – informed us that this colour feature Maximum body depth 109 14.4 – – – was widely used on board the Spanish Head length 216 28.6 – 24.9-27.7 – trawler fleet operating in the region, to Snout length 75 9.9 34.7 – 30.2-34.1 separate M.