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- Helminth parasites from the stomach of conger eel, Conger conger, from Madeira Island, Atlantic OceanPublication . Costa, Graça; Santos, Maria J.; Costa, Luísa; Biscoito, Manuel; Carvalho, Miguel Â. A. Pinheiro de; Moreira, Egberto MeloGeographic variations in the diversity and prevalence of helminth parasites of fish can provide important clues as to the relatedness of fish populations. In the present work, the stomachs of 64 conger eels, Conger conger, collected during 1999 and 2000, were examined for the presence of parasites. Four fish were infected with L3 stages of the nematode Anisakis simplex s.l. (Anisakidae), 1 with the nematode Cristitectus congeri (Cystidicolidae), 1 with the acanthocephalan Rhadi norhynchus pristis, 17 with postlarvae of Sphyriocephalus tergestinus (Eucestoda: Trypanorhyncha), and 55 with Lecithochirium spp. (Digenea: Hemiuridae). The hemiurids were the most abundant parasites, with a total of 385 individuals recovered. Strong aggregated distributions were found for both the digeneans, Lecithochirium musculus and Lecithochirium fusiforme, with variance-to-mean ratios (s 2 /x) and index of discrepancy (D) 13.98 and 0.672 (for L. musculus) and 8.08 and 0.90 for L. fusiforme, respectively. Intensity of L. musculus, L. fusiforme, and S. tergestinus showed significant relationships with depth of capture. Differences in number of species and prevalence were found between Madeira and the Atlantic coasts of the Iberian Peninsula.
- Helminth parasites of some coastal fishes from Madeira, PortugalPublication . Costa, Graça; Biscoito, ManuelOne hundred and fifty-one fish belonging to six different species, from Madeira, Atlantic Ocean, were examined for helminth infections. All the fish examined shared the same type of littoral habitat characterized by rocky and sandy bottoms. However their feeding ecology was slightly different resulting in variations in their parasite composition. In the blue damselfish, Abudefduf luridus, which is mostly herbivorous but ingesting also the associated invertebrate fauna, the digeneans dominated, while the Atlantic damselfish, Chromis limbata, which preys on plank tonic and benthic organisms, was infected mainly by anisakid nematodes, larval acanthocephalans and digenean lepocreadids, usually transmitted by planktonic and benthic invertebrates. Similarly in the Turkish wrasse, Thalassoma pavo, pelagically transmitted parasites clearly dominated (Hysterothylacium, Scolex pleuronectis, acanthocephalans). Despite the similarities in both habitat and feeding ecologies of the two sparids, Boops boops and Diplodus vulgaris, some differences were found in their parasite faunas. Both species shared the acanthocephalans and Hysterothylacium sp. but differed in the presence of Meinertia parallela in B. boops and its absence in D. vulgaris.
- Helminth parasites of the Atlantic chub mackerel, Scomber colias Gmelin, 1789 from Canary Islands, Central North Atlantic, with comments on their relations with other Atlantic regionsPublication . Costa, Graça; Cavallero, Serena; D’Amélio, Stefano; Paggi, Lia; Santamaria, Maria; Perera, Clara; Santos, Maria; Khadem, MahnazEleven parasite taxa were found infecting 68 Atlantic chub mackerel, Scomber colias Gmelin, 1789 from the Canary Islands, Central North Atlantic. The most abundant parasites were the gill monogenean Pseudokuhnia minor (P = 54.4%), larval anisakid nematodes (P = 11.8%) in the body cavity, a larval tetraphyllidean infecting bile ducts (P = 8.8%) and didymozoid digeneans infecting the gills (P = 7.4%). No correlation between fish length and abundance of infection with these parasites was found. Within the Atlantic, the comparison of present results with previous reports on the occurrence of parasites in this fish host, might suggest that there is more than one population unit of Atlantic chub mackerel in the Eastern Atlantic
- Helminth parasites of the oceanic horse mackerel Trachurus picturatus Bowdich 1825 (Pisces: Carangidae) from Madeira Island, Atlantic Ocean, PortugalPublication . Costa, G.; Moreira, E. Melo; Carvalho, M. A. A. Pinheiro deThe helminth parasite fauna of the oceanic horse mackerel Trachurus picturatus Bowdich 1825, caught off the Madeira Islands was composed of six different taxa. Prevalence and abundance of larval Anisakis sp. (Nematoda: Anisakidae) and Nybelinia lingualis (Trypanorhyncha: Tentaculariidae), the most common parasite taxa, were 24.3%, 0.9 and 37.9%, 0.7, respectively. Bolbosoma vasculosum (Acanthocephala: Polymorphidae) and the monogeneans Heteraxinoides atlanticus (Monogenea: Heteraxinidae) and Pseudaxine trachuri (Monogenea: Gastrocotylidae) were comparatively rare. The depauperate helminth fauna of the oceanic horse mackerel at Madeira compared to other geographical regions of the north-eastern Atlantic, namely the Azores banks and the West African coast, may be attributed to the paucity of nutrients off oceanic islands and to a low density of the fish population.