Phocanema decipiens (Nematoda: Anisakinae): experimental infections in marine copepods

• Published in: Canadian Journal of Zoology
• Main Author: McClelland, Gary
• Format: Article in Journal/Newspaper
• Language: English
• Published: Canadian Science Publishing 1982
• Subjects: West Arm; Phoca vitulina; Copepods; Tisbe furcata
• Online Access: http://dx.doi.org/10.1139/z82-075; http://www.nrcresearchpress.com/doi/pdf/10.1139/z82-075

Gravid female Phocanema decipiens were recovered from the stomachs of freshly killed harbour (Phoca vitulina) and grey seals (Halichoerus grypus). Ova dissected from the nematodes were incubated in seawater and the mean time to hatch varied from 8 days at 20 °C to 52 days at 5 °C. Posthatch survival of ensheathed larvae in seawater varied from 48 h at 20 °C to 140 days at 5 °C. Fifteen species of copepods collected from the North West Arm, Halifax, N.S., were exposed to freshly hatched larvae of P. decipiens. Exsheathed larvae of the parasite were subsequently detected in the haemocoel of 12 harpacticoid species including Danielsennia typica, Tisbe furcata, Ameira longipes, Enhydrosoma curticauda, and various undescribed species of the genera Halectinosoma, Tisbe, Alteutha, and Phyllothallestris and the family Diosaccidae. Phocanema decipiens also occurred in a cyclopoid copepod (Paracyclopina sp.) but calanoid copepods (Eurytemora sp. and Pseudocalanus sp.) did not become infected. The heaviest infections occurred in mature female copepods and prevalence and intensity of infection varied with host species. Adult male copepods and fifth copepodite females were lightly infected. Infected copepods survived for 3–7 days at 15 °C, 10–15 days at 10 °C, and 20–35 days at 5 °C. During the course of infection, larval P. decipiens grew an average of 60% and maximum of 130% in length but underwent little or no morphological change.