Size selection of common mussels, Mytilus edulis, by common eiders, Somateria mollissima: energy maximization or shell weight minimization?

1990 ◽  
Vol 68 (11) ◽  
pp. 2280-2283 ◽  
Author(s):  
Jan Ove Bustnes ◽  
Kjell Einar Erikstad
Keyword(s):  
Mytilus Edulis ◽  
Dry Weight ◽  
Somateria Mollissima ◽  
Shell Weight ◽  
Size Selection ◽  
Common Eiders ◽  
The Mean ◽  
Energy Maximization ◽  
Total Dry Weight ◽  
Selection Of

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.

Cycle de développement, croissance et production de Pisidium amnicum (Mollusca: Bivalvia) dans le Saint-Laurent (Québec)

1981 ◽  
Vol 59 (12) ◽  
pp. 2350-2359 ◽  
Author(s):  
B. Vincent ◽  
G. Vaillancourt ◽  
N. Lafontaine
Keyword(s):  
Population Dynamics ◽  
Sexual Maturity ◽  
Dry Weight ◽  
Mortality Rates ◽  
The Other ◽  
Annual Production ◽  
Bithynia Tentaculata ◽  
The Mean ◽  
Total Dry Weight ◽  
St Lawrence River

The population dynamics of Pisidium amnicum have been studied in one population of the St. Lawrence River over a 2-year period during which 19 samples were taken. The species can live up to 3 years and it is iteroparous; individuals generally attain sexual maturity after 1 year and they reproduce twice, once at 2 and once at 3 years of age. In adults, mortality is lower in winter than during the rest of the year and mortality rates are twice as high during the 1st year than during the 2nd year. Total dry weight (PT, in milligrams) is related to maximum length (L, in millimetres) according to the equation PT = 0.0283∙L3,80 and flesh dry weight (PC, in milligrams) is related to length as follows: PC = 0.007∙L3,18. The annual production to mean biomass (P/B) ratio is 1.4, the mean annual production being 1.298 mg/m2 of total dry weight and 107 mg/m2 of flesh weight. Comparing these results with those obtained for the gastropod Bithynia tentaculata in the same environment and at the same period of the year has shown that the growth of Pisidium amnicum is far less influenced by the temperature regime than that of the other species and that its production is at least 10 times lower.

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
Keyword(s):  
Mytilus Edulis ◽  
Blue Mussel ◽  
Shell Morphology ◽  
Subtidal Zone ◽  
Somateria Mollissima ◽  
Shell Mass ◽  
Common Eiders ◽  
In Captivity ◽  
Upper Intertidal ◽  
Shell Content

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.

scholarly journals Phenolic compound production by different morphological phenotypes in hairy root cultures of Fagopyrum tataricum Gaertn.

2011 ◽  
Vol 63 (1) ◽  
pp. 193-198 ◽  
Author(s):  
Nam Park ◽  
Li Xiaohua ◽  
Romij Uddin ◽  
Sang Park
Keyword(s):  
Phenolic Compound ◽  
Hairy Roots ◽  
Dry Weight ◽  
Root Cultures ◽  
Free Medium ◽  
Fagopyrum Tataricum ◽  
Murashige Skoog ◽  
Total Dry Weight ◽  
Selection Of ◽  
Morphological Phenotype

Hairy roots were obtained after inoculating sterile young stems of Fagopyrum tataricum with Agrobacterium rhizogenes R1000. The established roots displayed two morphological phenotypes when cultured on hormone-free medium containing Murashige-Skoog salts and vitamins. The thin phenotype had a higher growth rate than the thick phenotype. Further, the phenolic compound content of the thin phenotype was higher than that of the thick phenotype. In terms of their total dry weight, the thin phenotype produced an almost double amount of (-)-epigallocatechin as well as more than 51.5% caffeic acid, 65% chlorogenic acid, and 40% rutin compared to the thick phenotype after 21 days of culture. Therefore, selection of the optimal morphological phenotype of hairy roots of tartary buckwheat is an important factor for improved phenolic compound production.

Colonial nesting of the Hudson Bay eider duck

1983 ◽  
Vol 61 (11) ◽  
pp. 2424-2433 ◽  
Author(s):  
Josef K. Schmutz ◽  
Raleigh J. Robertson ◽  
Fred Cooke
Keyword(s):  
Open Water ◽  
Alarm Calls ◽  
Hudson Bay ◽  
Somateria Mollissima ◽  
Small Islands ◽  
Social Cooperation ◽  
Artificial Nests ◽  
Colonial Nesting ◽  
Common Eiders ◽  
Selection Of

This study was designed to evaluate the factors influencing colonial nesting of the Hudson Bay eider duck (Somateria mollissima sedentaria). Colonial nesting reflected both selection of appropriate nesting habitat by female common eiders and advantages gained through social cooperation in predator defense. Female common eiders preferred to nest on small islands or on promontories near the shore and under shrubs of medium height. Nesting densities were greatest where a relatively large expanse of open water facilitated landing and taking flight. Nesting females gave alarm calls and formed dense flocks in response to a fox model. Egg predation was less in artificial nests which were close to an incubating female than in those situated further away. There was no correlation between degree of nesting synchrony and density of females on an island. Certain groups, however, exhibited greater nesting synchrony than expected by chance and the variance in egg shape among these females suggested that they were genetically related.

Experimental Evidence of a Plant Meridian System IV.

1997 ◽  
Vol 25 (02) ◽  
pp. 135-142 ◽  
Author(s):  
T. Z. Hou ◽  
M. D. Li
Keyword(s):  
Sound Production ◽  
Net Photosynthesis ◽  
Dry Weight ◽  
Phaseolus Vulgaris L ◽  
Net Photosynthesis Rate ◽  
Bush Bean ◽  
Agricultural Plants ◽  
The Mean ◽  
Total Dry Weight ◽  
Growing Conditions

We have shown previously that plants exhibit functional characteristics similar to the meridian system in humans and animals, such as high potential and low electrical resistance, high temperature, and spontaneous sound production. Here we will show the effect of acupuncture on plants. When plants of Phaseolus vulgaris L. pole bean (cv. Kentucky wonder) and bush bean (cv. Slenderette) were subjected to acupuncture by inserting two needles into opposite sides of the stem of the unifoliolate buds, it was found that acupuncture strengthened the growth and development of the plants. Two repeated experiments showed that the mean net photosynthesis rate of plants subjected to acupuncture increased about 20.5%, the mean transpiration 27.2%, the growth and total length of internodes 22.5%, and the total dry weight of shoots from the cotyledon to the apex 22.9%, in comparisons with control plants under the same growing conditions. In addition, treated plants flowered three days earlier and had 14.4% more fruit than the untreated control plants. Thus, acupuncture may serve as a viable technique for increasing yield in agricultural plants.

A large molluscivore bird (Common Eider, Somateria mollissima) is able to discriminate quality of blue mussels (Mytilus edulis) based on size and provenance

2015 ◽  
Vol 93 (8) ◽  
pp. 655-663 ◽  
Author(s):  
Elisabeth Varennes ◽  
Sveinn A. Hanssen ◽  
John C. Bonardelli ◽  
Magella Guillemette
Keyword(s):  
Energy Balance ◽  
Mytilus Edulis ◽  
Energy Intake ◽  
Prey Size ◽  
Prey Selection ◽  
Somateria Mollissima ◽  
Shell Material ◽  
Blue Mussels ◽  
Common Eiders

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.

scholarly journals Pengaruh Berbagai Campuran Media yang Diperkaya Mikoriza Terhadap Pertumbuhan Benih Petai (The Effect of Several Media Mixtures Enriched by Mycorrhiza for Stink Bean Seedlings Growth)

2020 ◽  
Vol 29 (2) ◽  
pp. 169
Author(s):  
Deni Emilda ◽  
Ni Luh Putu Indriyani ◽  
NFN Muryati ◽  
NFN Sunyoto
Keyword(s):  
Seedling Growth ◽  
Block Design ◽  
Dry Weight ◽  
Treatment Unit ◽  
Bean Seedling ◽  
Bean Plants ◽  
West Sumatra ◽  
Total Plant ◽  
Total Dry Weight ◽  
Selection Of

<p>Media tanam mempunyai peran penting dalam menghasilkan benih petai bermutu. Namun, informasi mengenai media tanam yang dapat memacu pertumbuhan benih dan menghambat serangan penyakit tular tanah pada tanaman petai belum banyak tersedia. Tujuan dari penelitian ini adalah untuk memperoleh satu komposisi media terbaik untuk pertumbuhan benih petai. Penelitian dilaksanakan pada bulan September 2017 – April 2018 di Kebun Percobaan Sumani Balai Penelitian Tanaman Buah Tropika Solok, Sumatra Barat. Rancangan percobaan yang digunakan adalah Rancangan Acak Kelompok Lengkap (RAKL) dengan 10 perlakuan dan tiga ulangan, setiap unit perlakuan terdiri atas 30 tanaman. Perlakuan yang digunakan adalah 10 komposisi media yang terdiri atas kombinasi dua atau tiga bahan yang terdiri atas tanah, pupuk kandang, kompos, dan arang sekam serta penambahan agens hayati mikoriza. Hasil penelitian menunjukkan bahwa media terbaik untuk pertumbuhan benih petai sampai 6 bulan setelah transplanting adalah tanah: pupuk kandang = 1 : 1 (v/v) di mana menghasilkan bobot kering tanaman sebesar 24,47 g sementara media yang sama dengan penambahan mikoriza menghasilkan bobot kering tanaman lebih tinggi, yaitu sebesar 29,94 g, namun tidak berbeda secara signifikan dengan media tanpa penambahan mikoriza. Hasil penelitian ini dapat digunakan sebagai dasar pemilihan media untuk perbenihan petai.</p><p><strong>Keywords</strong></p><p>Campuran media; Mikoriza; Pertumbuhan; Petai</p><p><strong>Abstract</strong></p><p>Planting media used has an important role in producing quality stink bean seedling. However, information about planting media that can enhance seedling growth and inhibit infectious soilborne diseases on stink bean plants is not yet available. The purposes of this study were to obtain the best media compositions for the growth of stink bean seedlings. The research was conducted in September 2017 – April 2018 at Sumani Experimental Station of Balitbu Tropika, Solok, West Sumatra. The experimental design used was Randomized Complete Block Design (RCBD) with 10 treatments and three replications in which each treatment unit consisted of 30 plants. The treatments used were 10 media compositions consisting of a combination of two or three materials comprising soil, manure, compost, and rice husk charcoal and the addition of mycorrhizal biological agent. The results showed that the best medium for stink bean seedling growth up to 6 months after transplanting was soil: manure = 1 : 1 (v/v) which produced total plant dry weight 24.47 g whereas the same media with addition of mycorrhiza produced higher total dry weight 29.94 g, however this result did not show significantly different with treatment without mycorrhiza. This result can be used for media selection of stink bean seedlings.</p>

A Method for Measuring Growth in Living Barnacles (Crustacea: Cirripedia)

1993 ◽  
Vol 73 (3) ◽  
pp. 723-726 ◽  
Author(s):  
Marilyn S. Darling ◽  
Karl M. Wilbur
Keyword(s):  
Sea Water ◽  
Shell Growth ◽  
Dry Weight ◽  
Regression Equations ◽  
Balanus Amphitrite ◽  
Shell Weight ◽  
Buoyant Weight ◽  
Weight Method ◽  
Total Dry Weight ◽  
Non Destructive

A buoyant-weight method is described for the non-destructive estimation of fresh weight, total dry weight, shell weight and dry weight of organic matter in living barnacles Balanus amphitrite amphitrite Darwin. The method involves developing regression equations relating weight in air of these parameters to the buoyant weight of living barnacles in sea water. Buoyant weights of barnacles can then be used with the regression equations to obtain the weight in air of these consitituents, making possible the measurement of rates of shell growth and growth in dry weight without disturbance to the living animal. The method has been developed for the analysis of groups of juvenile barnacles cultured on coverslips, ranging in total dry weight from 1 to 60 mg, and for single mature individuals from 75 to 800 mg total dry weight. The buoyant-weight method has been used to measure shell growth of 2–3 mg d-1 in barnacles of 48 mg mean initial total dry weight cultured at 28°C.

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