The role of pelagic swarm fish (Myctophidae: Teleostei) in the oceanic life cycle of Anisakis sibling species at the Mid-Atlantic Ridge, Central Atlantic

Abstract

First information is provided on the parasitation and feeding ecology of the myctophid fish species Myctophum punctatum and Notoscopelus kroyeri from the Mid-Atlantic Ridge (MAR), Central Atlantic. Four different parasite species were found in both fish with a similar high prevalence and intensity of infestation. The digeneans Gonocerca phycidis and Lethadena sp. were isolated as adults from the stomach, larval tetraphyllidean cestodes (Scolex pleuronectis) from the intestine, and genetically identified larval anisakid nematodes of Anisakis simplex (s.s.) from the body cavity. No further Anisakis sibling species could be identified. Both myctophids had small pelagic crustaceans, mainly copepods and hyperiids, within their stomach contents. Ostracods, euphausiids, decapods, and amphipods were minor food components, demonstrating the pelagic environment for both fish. The recorded parasites including the anisakid A. simplex (s.s.) perform pelagic life cycles within the region, benefiting from extensive diurnal vertical migrations of their fish hosts. Comparison of the host range among the anisakis sibling species suggests that the A. simplex complex has low host specificity, infecting toothed and baleen whales on their extensive oceanic migrations. This contrasts the Anisakis physeteris complex that is restricted to toothed whales of the families Kogiidae and Physeteridae. Specificity in the teleost intermediate hosts for both complexes seems to be low, and sympatric occurrence of different siblings within the same intermediate hosts is likely. Myctophid swarm fish as important copepod feeders at the MAR significantly contribute to the oceanic anisakid nematode life cycle, especially considering the 100% prevalence and high intensity of infestation. Further genetic identification of Anisakis nematodes is needed in order to understand the sibling species distribution, along the MAR and within other oceanic environments.

Parasite fauna of the mediterranean grenadier Coryphaenoides mediterraneus (Giglioli, 1893) from the Mid-Atlantic Ridge (MAR)

“…and the nematode Anisakis simplex (s. s.) . The myctophids Myctophum punctatum and Notoscopelus kroyeri were both infected with the digeneans Gonocerca phycidis, Lethadena sp., tetraphyllidean cestodes and A. simplex (s. s.) (Klimpel et al 2008a). The parasite fauna of the benthal representative C. mediterraneus was the most species rich, with 16 different parasite species and including 6 adult digeneans and 5 adult nematodes (present study).…”

“…Similar to the cestodes, the nematode A. simplex s. l. uses invertebrates as first and larger crustaceans or teleosts as second intermediate hosts (Klimpel et al 2004(Klimpel et al , 2008a. However, Anisakis matures in marine mammals such as cetaceans (Anderson 2000, Køie 2001a, and these generalist larvae penetrate into deep waters through vertically migrating hosts (Palm and Klimpel 2008).…”

“…Klimpel et al 2007Klimpel et al , 2008aKritsky and Klimpel 2007;Moravec and Klimpel 2007;Busch et al 2008;Palm and Klimpel 2008). A species poor bathypelagic zone that is composed of cestodes, larval nematodes and some digeneans changes towards the deep-sea floor into a diverse parasite fauna, clearly dominated by adult nematodes and digeneans.…”

Anisakis (Nematoda: Ascaridoidea) from Indonesia

“…These 3 species were exclusively found in the pelagic, oceanodromous and migratory carangid Auxis rochei. According to Klimpel et al (2008), Mattiucci & Nascetti (2007 and Kellermanns (2009), A. berlandi and A. pegreffii together with A. simplex (s.s.) form the A. simplex s.l. complex of species that are most common in temperate to cold regions, e.g.…”

Global assessment of molecularly identified Anisakis Dujardin, 1845 (Nematoda: Anisakidae) in their teleost intermediate hosts

“…Population-based multilocus enzyme-electrophoresis (MAE) as well as Pcr-based approaches such as Pcr-rFlP (restriction Fragment length Polymorphism), sscP (single-strand conformation Polymorphism) or DNA sequencing of genetic markers have remarkably increased our knowledge of the actual species diversity and species composition (e.g. Anderson et al 1998, Klimpel et al 2008. Application of these methods to taxonomic studies of Anisakis spp.…”