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"Paying attention to expiration labels: the importance of non-predatory death for survivorship and the fate of production”

A seminar by Wendy Gentleman, Departments of Engineering Mathematics & Oceanography, Dalhousie University, Canada.

Info about event


Tuesday 9 October 2018,  at 14:00 - 16:00


Frokoststsuen building 1135 2nd floor (Aquatic Biology).


Peter Grønkjær


Estimation of mortality is essential for understanding and predicting population dynamics and associated ecological linkages. However, in many cases standard methods do not distinguish among types of mortality, nor do they consider that samples may include dead individuals, which can lead to misinterpretation and bias. Here I present theory I developed to explain how non-predatory death, or "expiration", influences in situ abundances. I tell the story of the curious case of negative egg mortalities for a marine copepod, Calanus finmarchicus, in the Labrador Sea, and the hidden significance of egg hatching success. Notably, I show that egg viability can have significant effects on estimates of early stage mortality and survivorship, and that its importance will be masked by the common practice of aggregating early stages. Based on this analysis, I make recommendations for how to consider expiration in designing modelling and empirical studies.