Table 4.

Energy density of prey categories in the Harlequin Duck risk model.

Prey Category	Energy Density J·mg dry weight−1	References
Gastropods (a)	16.35	ii, iii, iv, v
Mussels (b)	19.36	ii, v
Clams (c)	18.35	ii, iv
Crustaceans (d)	14.28	i, ii, iv, v, vi
Fishes (e)	19.05	i, iii, vi
Other invertebrates (f)	12.36	i, ii, iv

Notes:

• (a)
  Mean of samples of 2 species of Littorina and 6 species of Margarites.
• (b)
  Mean of 4 samples of Mytilis edulis.
• (c)
  Mean of samples of 9 species of clams.
• (d)
  Mean of samples of 9 species of crustaceans.
• (e)
  Mean of samples of herring eggs, salmon eggs, and sand lance.
• (f)
  Mean of samples of 23 species of polychaetes, echinoderms, and holothurians.

References:

• (i)
  Cummins and Wuycheck (1971).
• (ii)
  Wacasey and Atkinson (1987).
• (iii)
  Bishop and Green (2001).
• (iv)
  Dean et al. (2002).
• (v)
  McKinney et al. (2004).
• (vi)
  Elliott and Gaston (2008).