Italian Journal of Food Safety 2018; volume 7:6893 A case study on the labeling of FishStat Plus data sources, the total fishery bottarga produced in Sardinia production of mullets from the Eastern Correspondence: Pierluigi Piras, Scuola di Central Atlantic was over 30 thousand Dottorato di Ricerca in Produzione e from ovaries of grey mullets tonnes in 2010 (Harrison, 2016). They are Sicurezza degli Alimenti di Origine Animale, (Mugil cephalus and Mugil members of the order Mugiliformes, repre- Dipartimento di Biologia Animale, Università degli Studi di Sassari, via Vienna sented by a single family, and including capurrii) caught in Eastern 2, 07100 Sassari, Italy. Central Atlantic coasts officially 62 species belonging to 14 genera Tel. +39.339.2056525 - Fax: +39.079.229458. (Thomson, 1997). Recently, (Whitfield et E-mail: [email protected] al., 2012) it was proposed to recognize 20 Pierluigi Piras,1 Francesco Sardu,2 mullet genera including 70 species (11 of Key words: Grey mullets, Species identifica- Domenico Meloni,3 which belong to the genus Mugil). tion, Fish products, Bottarga. Maria Vittoria Riina,4 Systematics of Mugilidae are still much 4 4 debated and based primarily on morpholog- Acknowledgments: the Authors thank Chiara Beltramo, Pier Luigi Acutis Giuseppe Damele, whose professional colla- 1 ical characters, but those classically used in Veterinary Public Health and Food boration in executing fish photographs has species identification are remarkably simi- Security Service of the Region of been extremely helpful. lar within this family (Durand et al., 2012) Sardinia, Cagliari; 2Oristano Local and make quite challenging species identifi- Contributions: the authors contributed equally. Socio-Sanitary Area of Sardinia Public cation (Gonzales-Castro and Ghasemzadeh, Company for Health Protection, 2016). Using a mitochondrial gene-based Conflict of interest: the authors declare no 3 Oristano; Department of Veterinary phylogeny as criterion, Mugilidae potential conflict of interest. Medicine of the Sassari University, classification was recently proposed (Xia et Funding: none. Sassari; 4Genetics and al., 2016). While not disputing such Immunobiochemistry Laboratory of the author’s molecular results, Harrison (2016) Received for publication: 10 July 2017. Zooprophylactic Institute of Turin, Italy found that they disagree with morphologi- Revision received: 29 August 2017. cal analyses, and the nomenclature does not Acceptedonly for publication: 7 September 2017. seem to be properly used in commercial and research fisheries communities and by other This work is licensed under a Creative applied fieldworkers who might not be Commons Attribution-NonCommercial 4.0 International License (CC BY-NC 4.0). Abstract familiar with the systematic literature. Traditionally, the features of diagnosticuse The aim of this case study is to show ©Copyright P. Piras et al., 2018 value for Mugilidae include (Thomson, how traditional and molecular methods can Licensee PAGEPress, Italy 1997): the presence or absence of an adi- Italian Journal of Food Safety 2018; 7:6893 be employed to identify the Mugilidae pose eyelid (this character is commonly doi:10.4081/ijfs.2018.6893 species currently used in Sardinia (Italy) to employed to differentiate the genus Mugil produce the traditional bottarga for the pro- from remaining genera of the family), the cessing of their ovaries. A total of six spec- origin of the various fins and the number of imens of Mugil cephalus (n=3) and Mugil the Storia naturale di Sardegna (Cetti, fin rays, the linear morphometric measure- capurrii (n=3) were subjected to external 1777), in which it is reported that several ments of body proportions using the tradi- morphology and meristic measurements. species of mullets are found in the tional measures employed on fishes Subsequently, tissue samples of white mus- Sardinian Sea, but that: ... as far as I am (Harrison, 2016). cle and ovaries from three individuals per concerned, having observed these mullets, I Mugil cephalus (Linnaeus, 1758) is dif- species were underwent PCR-sequencing have not found any difference indicating fused worldwide and according to FAO is assay of mitochondrial DNA cytochrome that they could be considered different marketed as flathead grey mullet and MUF oxidase subunit I (COI). The external mor- species. The morphological distinction (3-Alpha Species Codes). Mugil cephalus is phology and meristic characters showed a between the various species belonging to an important species for both aquaculture sufficient level of reliability in the identifi- the Mugilidae has always been a difficult and fisheries, and in many regions of the cation between the two species. At theNon-commercial same task because of the extreme homogeneity of world it is captured during the spawning time, the molecular techniques showed the the family. In particular, referring to the sys- migration to harvest the egg roe which is discriminatory power and confirmed the tematic of Mugilidae, in the eleventh vol- salted and dried prior to be marketed as a correct species identification in all the sam- delicatessen (Livi et al., 2011). Linnaeus, ume of the Histoire naturelle des poissons, pling units. DNA barcoding may be an referring briefly to this species in his Valenciennes (1836) reported that ...in gen- effective aid to traditional taxonomy and Systema Naturae (1758), stated: Botargo eral, the great similarity between species of can facilitate accurate species identification italorum ex hujus ovis. In Italy, the botargo this genus makes their distinction one of the among the Mugilidae. or mullet roe, is traditionally produced from most difficult tasks in Ichthyology. flathead grey mullet’s egg roe, and market- Describing the Mugil cephalus, the same ed as bottarga. This name derives from the author reported that …precisely aligned Arabic word batārikh, which in turn, with the second dorsal fin is the anal, pre- Introduction derives from the greek-byzantine term senting eight soft rays. Despite its global Mugilidae are coastal fishes found in ootàrichon meaning dried and salted fish spread in both hemispheres, Mugil cephalus temperate, subtropical and tropical regions eggs. In the Sardinian language (Italy), is has a discontinuous distribution. As it will within marine, brackish and freshwater called butàriga, preserving a strong asso- be reported later, the key features regarding habitats worldwide and represent an impor- nance with the original Arabic word. its taxonomic status have been raised in tant food source in several Mediterranean Moreover, the technological process of grey many genetic studies, most of which sug- and Atlantic countries. According to FAO’s mullets bottarga was formerly described in gest that this scientific name includes a [page 6] [Italian Journal of Food Safety 2018; 7:6893] Applied Study species complex (Whitfield et al., 2012) or, phological characters remain the corner- hensive molecular systematic account of the in other words, that Mugil cephalus, once stone of taxonomy. However, there are dif- Mugilidae using nucleotide sequence varia- presented as an example of globally distrib- ficulties in relying primarily on morphology tion at three mitochondrial loci (16S rRNA, uted species, is now shown to harbor sever- when attempting to identify fishes from cytochrome b and cytochrome oxidase I) al cryptic species (Durand et al., 2012). isolated portions or processed products from fifty-five species. Mugil capurrii (Perugia, 1892) inhabits (Ward et al., 2009). In this regard, it has Currently, the use of a universally only the Eastern Central Atlantic and been long recognized that nucleic acids accepted short DNA sequence for identifi- according to FAO is marketed as leaping sequence diversity, whether assessed direct- cation of species (DNA barcoding or African mullet and MUO (3-Alpha Species ly or indirectly through protein analysis, can Barcode) has been proposed for many Codes). It was initially described as having be used to discriminate species. By using groups of animals, both invertebrate and the second dorsal fin behind the anal. At a these methods, the identification of Eastern vertebrate, and a fragment of the mitochon- later time, Tortonese (1963) highlighted one Central Atlantic Mugilidae species has been drial gene cytochrome c oxidase subunit I of the key features allowing to differentiate firstly proposed (Trape et al., 2009) by PCR (COI), is the most used sequence of DNA it in respect to the Mugil cephalus, since his restriction fragment length polymorphism barcoding. In fact, within-species variation anal fin invariably presented nine soft rays. (RFLP) analysis of mitochondrial 16S ribo- for this gene is low if compared with Other authors (Trewavas and Ingham, somal RNA region. The grey mullets from between-species variation. Therefore, 1972) published a key to the mullets African waters and in particular from south- species are regularly identified by a particu- species, with the purpose of supplementing ern Mauritania to Senegalese coast are also lar sequence or by a tight cluster of very the section on the Mugilidae in the fishes increasingly represented in international similar sequences. The effectiveness of this checklist of the Northeastern Atlantic and trade of fishing products. Ovaries of large gene region for species-level identifications Mediterranean (valid as to genera only species such as Mugil cephalus are specifi- was recently validated for application within the region). The following key was cally exported