Vol. 131: 133–142, 2018 DISEASES OF AQUATIC ORGANISMS Published November 6 https://doi.org/10.3354/dao03294 Dis Aquat Org Parasites of amberjacks from the archipelago of Madeira, Eastern Atlantic Bárbara Cavaleiro1,2, Margarida Hermida2,3,4,*, Aurélia Saraiva1,5 1University of Porto, Faculty of Sciences, Biology Department, Rua do Campo Alegre, Edifício FC4, 4169-007 Porto, Portugal 2MARE-Madeira, Marine and Environmental Sciences Centre, Quinta do Lorde Marina, 9200-044 Caniçal, Madeira, Portugal 3CIIMAR-Madeira, Interdisciplinary Centre of Marine and Environmental Research of Madeira, Edifício Madeira Tecnopolo, Caminho da Penteada, 9020-105 Funchal, Madeira, Portugal 4Oceanic Observatory of Madeira, Edifício Madeira Tecnopolo, Caminho da Penteada, 9020-105 Funchal, Madeira, Portugal 5CIIMAR, Interdisciplinary Centre of Marine and Environmental Research, Terminal de Cruzeiros do Porto de Leixões, Av. General Norton de Matos, 4450-208 Porto, Portugal ABSTRACT: Amberjacks, Seriola spp., are a group of carangid fishes of economic importance for fisheries and aquaculture worldwide. A survey of the parasites of greater amberjack S. dumerili and almaco jack or longfin yellowtail S. rivoliana from the Madeira archipelago (including the Madeira and Selvagens Islands) was carried out. This work is the first parasitological study of these 2 species in the Eastern Atlantic. A total of 14 parasite taxa were detected in the 47 fish ana- lysed: Allencotyla mcintoshi, Stephanostomum petimba, Rhadinorhynchus sp. and Caligus aeso- pus (in both Seriola spp.); Dionchus agassizi, Zeuxapta seriolae, Tormopsolus orientalis, Didymo- cystis sp. and Anisakis sp. (in S. rivoliana); Tetrochetus coryphaenae, Stephanostomum sp., S. ditrematis, Oncophora melanocephala and Hysterothylacium seriolae (in Seriola dumerili). The monogenean Dionchus agassizi and the nematode O. melanocephala constitute new host records for the genus Seriola, and the species Allencotyla mcintoshi, Z. seriolae, Tormopsolus orientalis, H. seriolae, and C. aesopus are reported in the region of Madeira for the first time. Some of the parasites detected, in particular Z. seriolae and C. aesopus, could constitute a threat to amber- jack aquaculture, and measures should be taken to prevent their introduction into sea cages. KEY WORDS: Amberjack · Seriola dumerili · Seriola rivoliana · Madeira · Parasites · Atlantic · Portugal Resale or republication not permitted without written consent of the publisher INTRODUCTION jack or longfin yellowtail S. rivoliana (Carpenter & De Angelis 2016). Amberjacks are mainly distributed Amberjacks are a group of carnivorous, predatory in tropical to warm temperate waters (McEachran & fish that belong to the genus Seriola, family Carangi- Fechhelm 2010). In the Eastern Atlantic, they occur dae. They are valuable commercial species (Mazzola between the UK and West Africa, in cluding mainland et al. 2000, Fernandes et al. 2018), with high con- Portugal and the Madeira, Azores and Canaries sumer acceptance due to their excellent flesh quality archipelagos, and in the case of S. dumerili, also in (Sicuro & Luzzana 2016). Four species of this genus the Mediterranean Sea (Valls et al. 2011). Both S. occur in the Madeira archipelago: the Guinean dumerili and S. rivoliana are common in Madeiran amberjack Seriola carpenteri; greater amberjack S. waters, with higher abundance in the Selvagens dumerili; lesser amberjack S. fasciata; and almaco Islands, possibly due to the relatively unperturbed *Corresponding author: [email protected] © Inter-Research 2018 · www.int-res.com 134 Dis Aquat Org 131: 133–142, 2018 habitat of the Selvagens Marine Protected Area com- these, 30 fish came from the Selvagens Islands as pared to Madeira Island, where they may have been a seizure from illegal fisheries; 29 of them were somewhat overexploited by commercial fisheries identified as S. rivoliana and 1 as S. dumerili. Since (Hermida & Delgado 2016, Friedlander et al. 2017). it was not possible to observe the fish immediately, These species are pelagic and epibenthic in oceanic they were frozen, which is the most acceptable waters and live at between 5 and 45 m depth, but are method of conservation for evaluating parasite com- more common at depths of 30 to 35 m (Myers 1991). munity taxonomic composition (Kvach et al. 2018). Amberjacks are important not only for commer- A further 15 specimens of larger size, 1 S. rivoliana cial fisheries, but especially for aquaculture pro- and 14 S. dumerili from Madeira, obtained from duction (Sicuro & Luzzana 2016). Greater amber- recreational fisheries, were also sampled. In addi- jack is an important cultured species in Asia, with tion to this, 2 specimens of S. dumerili were ob - production exceeding 38 000 t annually in Japan tained from a local aquaculture facility (see Table 1). alone, and it has also been produced in the Medi- Fishes were identified according to Carpenter (2002), terranean since the 1980s (Sicuro & Luzzana 2016). McEachran & Fechhelm (2010) and Carpenter & De Almaco jack is already produced commercially, Angelis (2016). albeit on a smaller scale, in the southern USA and Fish were measured and weighed: total weight, Hawaii, with production reaching 500 t yr−1, and total length (TL), fork length (FL), girth and maxi- shows a good potential for aquaculture diversifica- mum body height of each fish were obtained. The sex tion elsewhere (Sicuro & Luzzana 2016). This spe- of each specimen was determined through visual cies has been recently introduced into aqua culture observation of the gonads. The gills and viscera were in Madeira, where the main production is gilthead extracted and examined under a stereomicroscope seabream Sparus aurata (Berenguer 2017). with 100× magnification. Parasites found were col- Due to the commercial importance of Seriola spp., lected, counted, washed in saline solution (10%) and some studies on their parasite communities in differ- stored in ethanol (70%) for morphological identifica- ent geographical areas have been published. There tion. When necessary, nematodes were cleared in a are a few publications from Australia (Sharp et al. solution of 1:1 ethanol:glycerol and moved to 100% 2003, Hutson et al. 2007) and the Mediterranean Sea glycerol after 48 h. (Grau et al. 1999, Bartoli & Bray 2004); however, as In addition to the parasitology study, the stomach far as we know, there are no studies about the meta- contents of S. rivoliana from the Selvagens Islands zoan parasite communities of Seriola spp. from the were examined, and prey items were quantified and Eastern Atlantic. Several metazoan parasites from individually identified with the aid of fish identi - different taxonomic groups have already been iden- fication guides. The stomach vacuity index was cal- tified in Seriola spp. and some of them can be poten- culated and percent abundance of each prey was tially dangerous to aquaculture production, causing quantified. mortalities, e.g. the monogeneans Zeuxapta seriolae (Montero et al. 2004) and Neobenedenia girellae (Hirayama et al. 2009). Parasite identification The main purpose of this study is to describe the metazoan parasite community of Seriola spp. from Morphological identification of the different para- the Madeira archipelago and compare it with the sites proceeded to the lowest possible taxon. Mono- parasite communities previously described in am - geneans were identified according to the descrip- berjacks. Furthermore, this study can contribute to tions of Rao & Madhavi (1967), Rohde (1978), the knowledge of parasite species which might con- Hendrix (1994), Montero et al. (2003) and Jones et al. stitute a risk to the aquaculture production of (2005). Identification of trematodes was based on Rao amberjacks. & Madhavi (1967), Bartoli & Bray (2004), Bartoli et al. (2004), Jones et al. (2005) and Repullés-Albelda (2013) for the Acanthocolpidae, and Bray & Gibson MATERIALS AND METHODS (1977) for the Accacoeliidae. Nematodes were identi- fied according to Rodrigues et al. (1975), Deardorff & Fish sampling Overstreet (1980), Moravec et al. (1999), Li et al. (2007) and Costa et al. (2009a), and copepod identifi- A total of 47 specimens of Seriola spp. were ob - cation followed Cressey (1991), Choe & Kim (2010) tained between August 2016 and October 2017. Of and Repullés-Albelda (2013). Cavaleiro et al.: Parasites of amberjacks from Madeira 135 Statistical analysis melanocephala (Fig. 1). Furthermore, 5 parasite species are new records for Madeira: Allencotyla Biological condition factors, including the gonado- mcintoshi, Zeuxapta seriolae, Tormopsolus orien- somatic index, hepatosomatic index, girth/length talis, Hysterothylacium seriolae, and Caligus aeso- ratio and Fulton’s K condition factor were determined pus (Fig. 1). according to Lloret et al. (2014). Prevalence, mean intensity and mean abundance of each parasite spe- cies were calculated according to Bush et al. (1997). Almaco jack For the sample of 29 almaco jacks from the Sel- vagens Islands, correlations between parasite abun- In the 29 S. rivoliana from the Selvagens Islands, dance and host parameters were assessed using which were considered the main sample, 8 species of Spearman’s rank correlation (rS). Host parameters metazoan parasites were found: Allencotyla mcin- used were total length, weight, K and girth/length toshi Van Beneden & Hess, 1863, Dionchus agassizi ratio. Fisher’s test was used to assess differences in Goto, 1899 and Zeuxapta seriolae (Meserve, 1938) prevalence between the sexes.