Diversity of sea lice (Copepoda: Caligidae) parasitic on marine fishes with commercial and aquaculture importance in Chamela Bay, Pacific coast of Mexico by using morphology and DNA barcoding, with description of a new species of Caligus Francisco Neptalí Morales-Serna a, ⁎, Carlos Daniel Pinacho-Pinacho b , Samuel Gómez c , Gerardo Pérez-Ponce de León a a Departamento de Zoología, Instituto de Biología, Universidad Nacional Autónoma de México, Ap. Postal 70-153, C.P. 04510, México D.F., México b Posgrado en Ciencias Biológicas, Instituto de Biología, Universidad Nacional Autónoma de México, Ap. Postal 70-153, C.P. 04510, México D.F., México c Instituto de Ciencias del Mar y Limnología, Unidad Académica Mazatlán, Universidad Nacional Autónoma de México, Joel Montes Camarena s/n, Mazatlán 82040, Sinaloa, México abstract article info Article history: Received 27 September 2012 Received in revised form 14 August 2013 Accepted 5 September 2013 Available online 13 Septemberr 3 Keywords: Siphonostomatoida Crustacean Fish parasites Aquaculture Phylogeny COI The occurrence of parasitic copepods of the family Caligidae on wild and cultured marine fishes from Chamela Bay, on the Pacific coast of Mexico, is reported. A total of 16 species of Caligus and 1 species of Lepeophtheirus were found on 19 wild fish species. The description of Caligus chamelensis n. sp. parasitizing Kyphosus elegans is presented. Among the species of Caligus reported here, Caligus serratus is the most common since it was found infecting 11 fish species. On cultured fish, Lutjanus gutattus and L. peru, only one species of Caligus, C. sclerotinosus was collected. DNA barcodes [mitochondrial cytochrome c oxidase subunit I (COI) gene sequences] were obtained for the majority of the sea lice species herein reported. The molecular analyses support the recog- nition of the new species and suggest that neither Caligus nor Lepeophtheirus are monophyletic. COI is shown to be a good candidate for parasitic copepod species identification, although a more robust reference database is needed to expand our ability to accomplish a molecular identification. © 2013 Elsevier Ireland Ltd. All rights reserved. 1. Introduction Promotion of aquaculture in offshore waters has been increasing worldwide. Finfish farms have been using sea cages as a suitable meth- od of aquaculture. However, there are some problems related to water quality and flow as well as to the presence of some other marine organ- isms in the cages, such as parasites which may cause diseases and mortality [1,2]. Populations of ectoparasites with direct life cycles increase under farming conditions since aggregation of fish in cages may facilitate the spread of infections [2]. That is particularly true for parasitic copepods the importance of which as disease causing agents has become evident [3]. Members of the family Caligidae, mainly species of Caligus Müller, 1785 and Lepeophtheirus Nordmann, 1832, represent a group of siphonostomatoid copepods commonly known as “sea lice” which have impacted finfish aquaculture worldwide. For instance Caligus amblygenitalis Pillai, 1961 and Caligus chiastos Lin & Ho, 2003 were significantly associated with the severity of gross eye damage in south- ern bluefin tuna farmed in South Australia [4]; Caligus epidemicus Hewitt, 1971 is an important pathogen in Asia, causing mortality in more than 10 marine cultured fish species [5]; Caligus orientalis Gusev, 1951 often causes serious problems at fish farms in brackish-water regions of Japan, Taiwan and China [6]; Caligus rogercresseyi Boxshall & Bravo, 2000 has been the most important parasite for the salmon industry in Chile [7,8]; and Lepeophtheirus salmonis (Krøyer, 1837) causes serious damage in farms of Atlantic salmon in Canada, Ireland, Norway and Scotland [9,10]. Additionally, a decline of wild fish popula- tions in areas surrounding sea cages has been ascribed to sea lice epidemics [11,12]. Development of marine finfish culture is taking place in Mexico, with important efforts to scale-up production of highly valued food fishes (e.g. [13–15]). In particular, wild juvenile snappers, Lutjanus guttatus (Steindachner, 1869) and Lutjanus peru (Nichols & Murphy, 1922), are captured and grown in sea cages in coastal waters of Jalisco, western Mexico. Under these circumstances, information on potential threats by sea lice is needed in order to provide a baseline for future studies such as those on biosecurity, risk analysis and epidemiology, for disease prevention, control and management [16]. This paper is part of an ongoing survey of the parasitic copepods occurring in marine fishes of Chamela Bay (Mexican Pacific), including Parasitology International 63 (2014) 69–79 ⁎ Corresponding author at: Instituto de Biología, UNAM, 04510, México, D.F., México. Tel.: +52 5 56229131; fax: +52 5 55500164. E-mail addresses: neptalims@hotmail.com (F.N. Morales-Serna), danyboy_jd26@hotmail.com (C.D. Pinacho-Pinacho), samuelgomez@ola.icmyl.unam.mx (S. Gómez), ppdleon@ib.unam.mx (G. Pérez-Ponce de León). 1383-5769/$ – see front matter © 2013 Elsevier Ireland Ltd. All rights reserved. http://dx.doi.org/10.1016/j.parint.2013.09.005 Contents lists available at ScienceDirect Parasitology International journal homepage: www.elsevier.com/locate/parint