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Date Permissions Signed


Date of Award

Spring 1985

Document Type

Masters Thesis

Department or Program Affiliation

Biology Department

Degree Name

Master of Science (MS)



First Advisor

Schneider, David E. 1937-

Second Advisor

Summers, William C.

Third Advisor

Ross, June R. P.


The deposit-feeding gastropod Batillaria attramentaria lives upon algal mat, mud, gravelly mud and gravelly sand substrates at Chuckanut Mudflat, Washington and upon homogeneous sand at Semiahmoo Spit, Washington. The efficiencies and rates·of feeding by B. attramentaria on these substrates were studied in order to determine whether an optimal foraging strategy exists in this species.

Gut content analysis of snails taken from the various substrates revealed a fairly constant diet of sediment particles and diatoms, along with occasional animal fragments. Diatoms were ingested with efficiencies ranging from 38 to 51 percent; digestive efficiency increased with increasing availability of diatoms in sediments. Snail fecal pellets contained two to seven times more organic carbon than was contained in sediments. Carbon enrichment of pellets decreased with increasing availability of carbon in the sediments.

Gut residence times for materials ingested ranged from 260 to 400 minutes and varied inversely with the percentage of mud in the sediments. Pellet egestion rates increased with increasing percentage of mud in sediments, and ranged from 0.1 to 7.0 mg snail-1 hr-1.

Results for gut content analysis, gut residence and egestion rate experiments supported the hypothesis that Batillaria attramentaria feeds selectively on mud and diatoms regardless of sediment type. Egestion rate, diatom digestion and carbon enrichment results pointed to an energy optimization strategy in this species.




Batillaria attramentaria, deposit feeding gastropods


Western Washington University

OCLC Number


Subjects – Names (LCNAF)

Gastropoda--Washington (State)--Bellingham Bay

Geographic Coverage

Bellingham Bay (Wash.)




masters theses




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