Susan Waddy

Research Scientist
Fisheries and Oceans Canada

Current research and/or projects

Since joining DFO, Susan Waddy’s research has focused on the biology of the American lobster in support of the department’s priorities in aquaculture, resource conservation, and climate change. She shares her office with Zoe, a Maine coon cat who serves as the local ‘Rodent Control Officer.’ In her spare time, Zoe counts birds for Project Feederwatch, Bird Studies Canada.

Highlights include:

  • Demonstrated that emamectin benzoate, an in-feed drug used to control sea lice on farmed salmon, can cause egg-bearing lobsters to molt and lose their attached eggs. Subsequent work revealed that although egg-bearing lobsters are initially attracted to salmon feed, they rapidly ‘learn’ to reject fish pellets because of a preference for other foods.
  • Established that ‘jumbo’ lobsters, unlike smaller lobsters, often spawn two years in succession and are the most productive members of the population. This work corrected the widely-held belief that large lobsters rarely spawned.
  • Developed techniques for assessing maturity and determining reproductive status in female lobsters and integrated these into a standard approach to maturity studies (the ‘Waddy and Aiken Protocol’ published in 2005 in Trans. Am. Fish. Soc. 134:1075-1090).
  • Discovered a new species of nemertean that preys on lobster eggs.
  • Elucidated the complex mechanisms involved in the timing of seasonal spawning cycles in American lobsters and identified environmental control mechanisms in lobsters that are strikingly similar to those in many terrestrial vertebrates. Showed that the response to temperature and day length are diametric on either side of the winter solstice.
  • Demonstrated that the thermal requirements for growth, reproduction, and larval development in lobsters are not cumulative (as in the commonly used degree-days), but rather are a combination of threshold and cumulative phenomena.
  • Identified that the metamorphic molt of lobsters occurs during the scotophase in the form of a population-based daily rhythm entrained by photoperiod.

Research and/or project statements

Since joining DFO, Susan Waddy’s research has focused on the biology of the American lobster in support of the department’s priorities in aquaculture, resource conservation, and climate change. She shares her office with Zoe, a Maine coon cat who serves as the local ‘Rodent Control Officer.’ In her spare time, Zoe counts birds for Project Feederwatch, Bird Studies Canada.   

Key publications

  1. Waddy, S.L., and D.E. Aiken. 1985. Immunofluorescent localization of American lobster egg yolk protein in the alimentary track of the nemertean Pseudocarcinonemertes homari. Can. J. Fish. Aquat. Sci. 42:357-359.

  2. Waddy, S.L., and D.E. Aiken. 1985. Fertilization and egg retention in artificially inseminated female American lobsters, Homarus americanus. Can. J. Fish. Aquat. Sci. 42:1954-1956.

  3. Waddy, S.L., and D.E. Aiken. 1986. Multiple fertilization and consecutive spawning in large American lobsters. Can. J. Fish. Aquat. Sci. 43:2292-2294.

  4. Waddy, S.L., and D.E. Aiken. 1990. Winter temperature and spring photoperiod requirements for spawning in the American lobster (Homarus americanus). J. Shellfish Res. 9:41-43.

  5. Waddy, S.L., and D.E. Aiken. 1990. Intermolt insemination, an alternative mating strategy for the American lobster (Homarus americanus). Can. J. Fish. Aquat. Sci. 47:2402-2406.

  6. Waddy, S.L., and D.E. Aiken. 1992. Seasonal variation in spawning by preovigerous American lobster (Homarus americanus) in response to temperature and photoperiod manipulation. Can. J. Fish. Aquat. Sci. 49:1114-1117.

  7. Waddy, S.L., and D.E. Aiken. 1992. Environmental intervention in reproduction of the American lobster, Homarus americanus. J. Invert. Reprod. Develop. 22:245-252.

  8. Waddy, S.L., and D.E. Aiken. 1993. Mating and insemination in the American lobster, Homarua americanus. In: Crustacean Sexual Biology (R.T. Bauer and J.W. Martin, eds.), p. 126-144. Columbia University Press, New York.

  9. Waddy, S.L., and D.E. Aiken. 1995. Culture of the American lobster. In: Cold-Water Aquaculture in Atlantic Canada. 2nd ed. (A. Boghen, ed.), p. 145-188. The Canadian Institute for Research on Regional Development, Moncton.

  10. Waddy, S.L., and D.E. Aiken. 1995. Temperature regulation of reproduction in the American lobster. ICES mar. Sci. Symp. 199:54-60.

  11. Waddy, S.L., D.E. Aiken, and D.P.V. de Kleijn. 1995. Control of growth and reproduction. In: The biology of the Lobster Homarus americanus (J.R. Factor, ed.), p. 217-266. Academic Press, New York.

  12. Waddy, S.L., and D.E. Aiken. 2000. Timing of the metamorphic molt in American lobsters, Homarus americanus. Can. J. Fish. Aquat. Sci. 56:2324-2330.

  13. Waddy, S.L., and D.E. Aiken. 2000. Endocrinology and the culture of homarid lobsters. In: Recent Advances in Marine Biotechnology (M. Fingerman and R. Nagabhushanam, eds.), Vol. 4, Part A, Seaweeds and Invertebrates, p. 195-247. Science Publishers Inc., Enfield.

  14. Waddy, S.L., L.E. Burridge, M.N. Hamilton, S.M. Mercer, D.E. Aiken, and K. Haya. 2002. Emamectin benzoate induces molting in American lobster, Homarus americanus. Can. J. Fish. Aquat. Sci. 59:1096-1099.

  15. Waddy, S.L., and D.E. Aiken. 2005. Impact of invalid biological assumptions and misapplication of maturity criteria for size-at-maturity estimates for American lobster. Trans. Am. Fish. Soc. 134:1075-1090.

  16. Waddy, S.L., V.A. Merritt, M.N. Hamilton-Gibson, D.E. Aiken, and L.E. Burridge. 2007. Relationship between dose of emamectin benzoate and molting response of ovigerous American lobsters (Homarus americanus). Ecotoxicol. Environ. Saf. 67:95-99.

  17. Waddy, S.L., S.M. Mercer, M.N. Hamilton-Gibson, D.E. Aiken, and L.E. Burridge. 2007. Feeding response of female American lobsters, Homarus americanus, to SLICE®-medicated feed. Aquaculture (in press — doi: 10.1016/j.aquaculture.2007.04.060).