Sainte Mane and Chabot: Natural diet of Homarus amencanus off the Magdalen Islands 



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the 25- and 35-mni-CL size classe,s from the 10-20 mm CL 

 size classes. 



For each grouping, Figure 4 shows the specific abun- 

 dance of each food item plotted against its percent occur- 

 rence. Bivalves and flesh accounted for a large proportion 

 of stomach contents of the smallest lobsters (7-mm-CL 

 size class) and were found in >751 of stomachs, making 

 them the most important food items for this grouping. 

 Rock crabs, amphipods, and polychaetes contributed 0.2 

 to 0.4 of stomach volume when they were ingested, but 

 were found in fewer than 30'* of the stomachs. Macroalgae 

 and gastropods, on the other hand, were eaten by >50'; 

 of small lobsters but were ingested in small volumes. All 

 other prey categories contributed little to stomach volume 

 and were found in a small proportion of stomachs. 



Flesh and bivalves were also the most important food 

 items for the 10-20 mm CL lobster grouping (Fig. 4). They 

 accounted for 0.46 and 0.22 of stomach volume, respec- 

 tively, when they were ingested, and were found in 90' ^ 

 of stomachs. Rock crab was another important prey, with 

 a specific abundance of 0.32 and an occurrence of 41'r. 

 Pagurids, carideans, and echinoderms had high specific 

 abundances but were found in less than 5'^r of stomachs. 

 Gastropods and polychaetes were found in about 40'5c of 

 stomachs, but accounted for a small fraction of stomach 

 volume. All other prey categories constituted a small frac- 

 tion of the volume of very few stomachs. 



The two main food items of lobsters measuring 25-60 

 mm CL were rock crab and flesh: specific abundance was 

 high (0.34 and 0.38, respectively) and these food items 



