Anisakid parasites of two forkbeards (Phycis blennoides and Phycis phycis) from the eastern Mediterranean coasts in Tunisia

Abstract

Two gadiform species with a successive bathymetric and an ecological and economical importance in the Mediterranean fishing industry, Phycis blennoides and Phycis phycis, were selected for the present study. A total of 592 fresh specimens belonging to the Gadiformes genus were obtained from local commercial fisheries. The investigation was centred on anisakid parasites of 272 specimens of the greater forkbeard (P. blennoides) and 320 of the forkbeard (P. phycis) captured off the Mediterranean coasts of Tunisia (eastern Mediterranean Sea). Four species of nematodes were identified: Anisakis simplex s.1., Anisakis physeteris, Hysterothylacium aduncum and Hysterothylacium fabri. The total prevalence was 53.75% in the forkbeard and 51.47% in the greater forkbeard. The highest values of prevalence (38.75%, 2-14), mean intensity (6.74+/-3.4) and mean abundance (2.61) were all obtained for H. fabri L4 in the forkbeard. The most frequent parasite in the greater forkbeard was H. aduncum L3 with 32.35% (1-3) prevalence and values of 1.21+/-0.58 and 0.39 for mean intensity and mean abundance, respectively. The infestation parameters were also analysed according to the host length, and prevalence was highest in P. blennoides longer than 35 cm in respect of all anisakid species. Whilst in P. phycis, the highest prevalence, conditioned by H. fabri parasitisation, was found in fish with length reaching a maximum of more than 40 cm. When the data were grouped seasonally, clear patterns were observed for P. blennoides and P. phycis species, with prevalence and mean intensity of all the anisakid species peaking in spring and summer.

Red vent syndrome in wild Atlantic salmon Salmo salar in Scotland is associated with Anisakis simplex sensu stricto (Nematoda: Anisakidae)

“…More generally, the 15°C summer isotherm has moved 330 km north in the last 17 yr (McMahon & Hays 2006), and studies by Beaugrand et al (2008) in the North Atlantic showed that regions in which biome boundaries shifts occur are more vulnerable to the impact of climate change. There is a general tendency for parasitic infections to increase with temperature (Farjallah et al 2006), and rising water temperatures have been reported to directly influence the incidence of disease threats from parasitic infections (Harvell et al 1999, Hakalahti et al 2006, particularly in temperate regions where transmission is strongly related to 'windows' of suitable temperature ranges. Increased infection pressure (as has apparently occurred with salmon) due to warming waters has been reported for metazoans (Argulus coregoni and Diplostomum spathacum usually found in fish culture) in Finland (Hakalahti et al 2006).…”

Anisakis spp. burden in Trachurus trachurus

“…the number of hosts infected with one or more individuals of a particular parasite species, Bush et al, 1997) of larval anisakids can be very high (Chou et al, 2010). In some northern hemi-.......... sphere fisheries the prevalence has increased in recent years, enlarging the concern for human health and having adverse financial effects (Farjallah et al, 2006;Cabrera, 2010). There is an extensive world literature on Anisakis and anisakiosis.…”

Occurrence and molecular identification of Anisakis spp. from the North African coasts of Mediterranean Sea

“…as results of an interspecific hybridation between the two species of the A. simplex complex (Abollo et al 2003). The genus Anisakis was previously reported infecting some fish species from the North African coasts of central Mediterranean Sea (Farjallah et al 2006), although there are no studies that document distribution of the Anisakis larvae at species level in this area. The aim of the present work was to investigate, using RFLP genetic analysis and the molecular keys devised by D' Amelio et al (2000) implemented by Pontes et al (2005), the occurrence of larval forms of Anisakis spp.…”