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Table 1 Annual instantaneous mortality rates (z in year−1; z is the ratio of ln of numerical densities at start and end of the period of observation, multiplied by 365 and divided by length of observation period in days) as estimated for various age groups of the cohort of Pacific oysters born in 2002 in the German Wadden Sea by Diederich (2006) and Schmidt et al. (2008)

From: Extraordinarily low mortality rates reported in juvenile Pacific oysters in the German Wadden Sea

Age (years)

0.2–0.8

0.8 or 0.7–1.7

1.7–2.6

Z (year−1)

1.8

0.03 and 0.13

0.82 and 1.61

Percentage of mortality

84

3 and 12

56 and 80

Reference

Diederich (2006)

Schmidt et al. (2008)

Schmidt et al. (2008)

  1. Age expressed in years after a heavy settlement supposed to have taken place in September 2002. The z value for the youngest age group of 0.005 day−1 stated by Diederich (2006) was converted to an annual value of 1.8 year−1 (by multiplication by a number of days of 365)
  2. The two values given for the two older age groups refer to two different beds sampled by Schmidt et al. (2008)
  3. Annual mortality values are also shown as percentages of initial numbers
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Helgoland Marine Research

ISSN: 1438-3888

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