Atlantic codGadus morhuaL.: Visceral organ topography and the asymetrical distribution of larval ascaridoid nematodes in the musculature

Abstract

Abstract Visceral organ topography (VOT) in marine teleosts has been defined as the “spatial arrangement and contiguity of organs within the body cavity”, and it has been suggested that VOT may influence the habitat(s) occupied by the third-stage larvae (L3) of ascaridoid nematodes. Reports of an asymmetrical distribution of Anisakis (“whaleworm”) L3 and Pseudoterranova (“sealworm”) L3 in Atlantic cod Gadus morhuaL. prompted studies of VOT in this host. The left liver lobe dominates the left sagittal half of the body cavity and is largely contiguous with the stomach wall. Examination of ã 630 cod confirmed that more L3 occur in the left than in the right body musculature. Two hypotheses discussed in relation to the asymmetry both pertain to the liver. Feeding and growth of larval ascaridoids in fish are discussed briefly.