Effect of temperature on egg hatching and survival of larvae of Anisakis simplex B (Nematoda: Ascaridoidea)

• Published in: Canadian Journal of Zoology
• Main Authors: Brattey, John, Clark, Kirsten J.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Canadian Science Publishing 1992
• Subjects: Animal Science and Zoology; Ecology, Evolution, Behavior and Systematics; Lagenorhynchus albirostris; White-beaked dolphin; Copepods
• Online Access: http://dx.doi.org/10.1139/z92-041; http://www.nrcresearchpress.com/doi/pdf/10.1139/z92-041

Eggs of the parasitic nematode Anisakis simplex B, obtained from a white-beaked dolphin (Lagenorhynchus albirostris Gray), were incubated in seawater at constant temperatures from −0.7 to 24.3 °C and hatching times determined. Eggs hatched at all temperatures except −0.7 °C. The number of days until hatching ranged from 3 at 24.3 °C to 74–81 at 1.9 °C. There was a declining curvilinear relationship between temperature and both hatching time and duration of the hatching period. The hatching period increased and became more variable with decreasing temperature and ranged from 5 days at 24.3 °C to 55–72 days at 3.8 °C. The percentage of eggs that hatched at each temperature was variable but generally fell in the range 30–60% and was not correlated with temperature. Survival times of hatched larvae peaked at 75–105 days at 8.6 °C, with a minimum of 3–8 days at 24.3 °C. Dimensions of eggs (length, width, volume) differed significantly among individual worms but were not correlated with worm size (wet weight). Egg hatching and larval survival characteristics indicate a species adapted to cold-temperate waters and are consistent with the known distribution of A. simplex B. Preliminary experiments indicated that harpacticoid copepods will ingest newly hatched larvae of A. simplex B and become infected, suggesting that these microcrustaceans may be involved in the life cycle of the nematode.