Selection of blue mussels, Mytilus edulis, by common eiders, Somateria mollissima, by size in relation to shell content

1998 ◽  
Vol 76 (9) ◽  
pp. 1787-1790 ◽  
Author(s):  
Jan Ove Bustnes

The blue mussel, Mytilus edulis, is the most important food item for the common eider, Somateria mollissima, but the mussels eaten by eiders vary in length between both areas and seasons. The aim of this study was to experimentally test the hypothesis that common eiders try to minimize shell intake when selecting among mussels of different lengths. Two types of experiments were conducted using wild common eiders in captivity. Experiment 1 tested whether eiders could seek out the mussels with least relative shell content and highest flesh content from among mussels of an array of lengths. They selected the shortest mussels (<20 mm), which had the lowest shell content. In experiment 2, the eiders were given mussels of the same length class (26-31 mm), but with different shell morphology and shell mass, from the subtidal and upper intertidal zones. The birds only ate the subtidal-zone mussels with the lowest shell mass. The results of this study strongly indicate that reducing the amount of indigestible shell is an important factor for eiders selecting among mussels of different lengths.

2015 ◽  
Vol 93 (10) ◽  
pp. 783-789 ◽  
Author(s):  
Elisabeth Varennes ◽  
Sveinn A. Hanssen ◽  
John C. Bonardelli ◽  
Magella Guillemette

Benthivorous predators like sea ducks rely on abundant but low-quality food. Because they ingest whole blue mussels (Mytilus edulis L., 1758), including shells, they have to consume large quantities of food to maintain energy balance. Digestive processes may therefore limit energy assimilation in these predators, although selecting mussel types that minimize shell ingestion may improve foraging profitability. To test this prediction, we first quantified mussel quality from different sizes and habitats by measuring energy content and various features of mussel morphology. Then, we conducted digestive experiments on captive Common Eiders (Somateria mollissima (L., 1758)) fed with various mussel types to determine their impact on Eiders’ digestion. Aquacultured and small mussels were of better quality, because of higher energy content and less resistant shells. These mussel characteristics allowed faster digestive processes for an equal digestibility compared with large intertidal mussels. Previous studies showed that aquacultured and small mussels were generally preferred by sea ducks. Hence, prey-selection behaviours and digestive processes seem closely connected in these highly digestive-constrained predators.


2015 ◽  
Vol 93 (8) ◽  
pp. 655-663 ◽  
Author(s):  
Elisabeth Varennes ◽  
Sveinn A. Hanssen ◽  
John C. Bonardelli ◽  
Magella Guillemette

Molluscivore birds that forage on abundant but low-quality food have to ingest large quantities of food to achieve energy balance. Such a strategy is often associated with important digestive constraints limiting predator’s ingestion. Thus, these predators may use prey selection to ingest better-quality individuals among a generally low-quality prey population. Using captive Common Eiders (Somateria mollissima (L., 1758)) diving in a constant environment, we were able to examine their preferences for blue mussels (Mytilus edulis L., 1758) of varying qualities (different sizes or provenances). In addition, we studied the consequences prey selection had on Eiders’ energy intake rates and ingestion of flesh and shell material. Eiders selected 10–20 mm mussels and were able to discriminate and to select cultivated mussels from intertidal mussels. Prey selection allowed, in certain conditions of prey-size abundance, higher flesh and energy intake rates without increasing the ingestion of shell material. This study confirmed the energetic advantage that Eiders have when foraging in aquaculture sites, which explain the large depredation of preferred mussel sizes.


1990 ◽  
Vol 68 (11) ◽  
pp. 2280-2283 ◽  
Author(s):  
Jan Ove Bustnes ◽  
Kjell Einar Erikstad

Prey size selection by common eiders, Somateria mollissima, preying on common mussels, Mytilus edulis, in northern Norway is described. The mean length (± 1 SD) of mussels preyed upon was 13.9 ± 5.7 mm (range 3.5–38.1 mm). The dry flesh weight as a percentage of the total dry weight ranged from 4.2 to 8.6% in different body-length categories and was greatest in the mussels most frequently fed upon. There was a close negative correlation between the size of mussels fed upon and the estimated total shell weight that birds had to ingest to obtain their daily requirement of food (rs = −0.86). A hypothesis is proposed that common eiders select mussels of certain size classes to minimize the daily shell weight intake.


Genetics ◽  
2004 ◽  
Vol 166 (2) ◽  
pp. 883-894
Author(s):  
Liqin Cao ◽  
Ellen Kenchington ◽  
Eleftherios Zouros

Abstract In Mytilus, females carry predominantly maternal mitochondrial DNA (mtDNA) but males carry maternal mtDNA in their somatic tissues and paternal mtDNA in their gonads. This phenomenon, known as doubly uniparental inheritance (DUI) of mtDNA, presents a major departure from the uniparental transmission of organelle genomes. Eggs of Mytilus edulis from females that produce exclusively daughters and from females that produce mostly sons were fertilized with sperm stained with MitoTracker Green FM, allowing observation of sperm mitochondria in the embryo by epifluorescent and confocal microscopy. In embryos from females that produce only daughters, sperm mitochondria are randomly dispersed among blastomeres. In embryos from females that produce mostly sons, sperm mitochondria tend to aggregate and end up in one blastomere in the two- and four-cell stages. We postulate that the aggregate eventually ends up in the first germ cells, thus accounting for the presence of paternal mtDNA in the male gonad. This is the first evidence for different behaviors of sperm mitochondria in developing embryos that may explain the tight linkage between gender and inheritance of paternal mitochondrial DNA in species with DUI.


2021 ◽  
Vol 167 ◽  
pp. 112295
Author(s):  
Amina Khalid ◽  
Aurore Zalouk-Vergnoux ◽  
Samira Benali ◽  
Rosica Mincheva ◽  
Jean-Marie Raquez ◽  
...  
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