Composition, Shell Strength, and Metabolizable Energy of Mulinia lateralis and Ischadium recurvum as Food for Wintering Surf Scoters (Melanitta perspicillata).

摘要: Decline in surf scoter (Melanitta perspicillata) waterfowl populations wintering the Chesapeake Bay has been associated with changes availability of benthic bivalves. The become more eutrophic, causing benthos available to scoters. subsequent decline oyster beds (Crassostrea virginica) reduced hard substrate needed by hooked mussel (Ischadium recurvum), one primary prey items for scoters, switch a opportune species, dwarf surfclam (Mulinia lateralis). composition (macronutrients, minerals, and amino acids), shell strength (N), metabolizable energy (kJ) these were quantified determine relative foraging values Pooled samples each item analyzed composition. Shell (N) was measured using crack compression test. Total collection digestibility trials conducted on eight captive For size range commonly consumed scoters (6–12 mm M. lateralis 18–24 I. recurvum contained higher ash, protein, lipid, per individual organism than lateralis. required significantly greater force No difference metabolized observed despite recurvum’s ash content harder Therefore, able obtain same amount from item, implying that they can sustain themselves if forced prey.