On the Specific Identity of the Larval Porrocaecum (Nematoda) in Atlantic Cod

Larval Porrocaecum sp. commonly infect Atlantic cod (Gadus callarias) in Canadian waters. Some of these larvae are known to be young stages of P. decipiens, but this is not proof that only one species of Porrocaecum parasitizes cod.The distribution of 13 marine species of adult Porrocaecum is review...

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Bibliographic Details
Published in:Journal of the Fisheries Research Board of Canada
Main Author: Scott, D. M.
Format: Article in Journal/Newspaper
Language:English
Published: Canadian Science Publishing 1956
Subjects:
Online Access:http://dx.doi.org/10.1139/f56-023
http://www.nrcresearchpress.com/doi/pdf/10.1139/f56-023
Description
Summary:Larval Porrocaecum sp. commonly infect Atlantic cod (Gadus callarias) in Canadian waters. Some of these larvae are known to be young stages of P. decipiens, but this is not proof that only one species of Porrocaecum parasitizes cod.The distribution of 13 marine species of adult Porrocaecum is reviewed. Only one species, P. decipiens, is known from Canadian Atlantic waters; its distribution is consistent with the distribution of infected cod.The frequency distribution of the lengths of about 875 larval Porrocaecum from cod was examined, as was that of the lengths of the oesophagus, ventriculus, and intestinal caecum of about 200 larvae. These suggest that only one species is present in the samples.Body proportions of larval Porrocaecum from cod agree more closely with those of adult P. decipiens than with those of 10 other marine species of adult Porrocaecum.It is concluded that the larval Porrocaecum in cod are probably conspecific.