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

• 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: General Medicine; atlantic cod
• Online Access: http://dx.doi.org/10.1139/f56-023; http://www.nrcresearchpress.com/doi/pdf/10.1139/f56-023

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.