L'incidence d'Aerococcus viridans var. homari dans le stock naturel de homards (Homarus americanus) des îles de la Madeleine (Québec), suite à une épidémie de gaffkémie dans un élevage in situ

1987 ◽  
Vol 44 (2) ◽  
pp. 368-372 ◽  
Author(s):  
Jacques Ménard ◽  
Bruno Myrand
Keyword(s):  
Homarus Americanus ◽  
Private Facility ◽  
La Madeleine ◽  
Magdalen Islands

In 1982, gaffkemia appeared in a private lobster (Homarus americanus) culture facility located in House Harbour lagoon in Magdalen Islands (Quebec, Canada). It caused the death of about 40 000 lobsters. The outbreak did not expand to the natural stock despite the fact that conditions seemed favourable for the spread of gaffkemia. In June 1983, only 2% of the lobsters sampled around the islands (6/300) were contaminated. By June 1984, no infected individuals were found either in the natural stock or from the private facility. Lobster fishing data from 1979 to 1985 confirm that gaffkemia did not affect natural stock.

scholarly journals A Noninvasive Method For In situ Determination of Mating Success in Female American Lobsters (Homarus americanus)

10.3791/50498 ◽  
2014 ◽  
Author(s):  
Jason S Goldstein ◽  
Tracy L Pugh ◽  
Elizabeth A Dubofsky ◽  
Kari L Lavalli ◽  
Michael Clancy ◽  
...  
Keyword(s):  
Mating Success ◽  
Homarus Americanus ◽  
Noninvasive Method

Ecology and Growth of Postlarval and Juvenile Lobster, Homarus americanus, off Îles de la Madeleine (Quebec)

1987 ◽  
Vol 44 (11) ◽  
pp. 1855-1869 ◽  
Author(s):  
Christiane Hudon
Keyword(s):  
Growth Factor ◽  
Size Structure ◽  
Stage Iv ◽  
High Growth ◽  
Homarus Americanus ◽  
Fine Tuning ◽  
Mean Size ◽  
Density And Biomass ◽  
Rocky Bottoms ◽  
La Madeleine

Lobsters, Homarus americanus were studied in various habitats off Îles de la Madeleine, Quebec, from June to October 1985. Density, biomass, and size structure were estimated quantitatively using underwater corrals (40 m2) on rocky bottoms or transects (200 m2) on sandy bottoms and eelgrass beds. On the basis of behavioural observations during capture, lobsters were divided into postlarvae (<25 mm carapace length, CL), juveniles (25–76 mm CL), and adults (>76 mm CL). Density, biomass, and size structure were closely related to the coarseness of the bottom. Density and biomass were greater and mean size was larger on algae-covered boulders than on bare stones. Postlarval and juvenile lobsters were most numerous on shallow rocky bottoms where high densities (0.8–3.8 ind∙m−2) of small lobsters (mean size from 23.8 to 35.5 mm CL) were captured. Low density of juveniles and adults occurred on sand covered with eelgrass. No resident lobsters were found on bare sand. Temporal variation of postlarval density was synchronous at the three stations investigated. Postlarval density decreased during the summer until the settlement of planktonic postlarvae in mid-August. Moulting activity occurred throughout the summer, with a peak in early July. Mean size values for stages V–XIV were fitted to the cumulated size distribution and were used to calculate the percent increment for each moult stage (growth factor) and the expected duration of each stage. The 2-mo duration of the stage IV settlement period could result in a size range of 6–21 mm CL (mean size 14.5 mm CL, stage VIII) for a cohort by the end of its first season of benthic growth. The transition from planktonic to benthic life was characterized by a decrease of the growth factor at stage V, which was subsequently compensated at stages VI and VII by high growth factor values. In the first three growth seasons, spring and summer moults exhibit higher growth factor values than fall moults. These seasonal variations result in regular oscillations of the growth factor dampening progressively between stages V and XIV, instead of the smooth decline hypothesized in previous studies. A combination of factors, such as cryptic behaviour, high substrate selectivity, gradual settlement over the late summer months, and variability in growth factor, reflect the very fine tuning of the lobster's early benthic life stages to the constraints of its physical environment.

Cannibals by night? In situ video monitoring reveals diel shifts in inter- and intra-specific predation on the American lobster

2013 ◽  
Vol 70 (11) ◽  
pp. 1635-1640 ◽  
Author(s):  
Noah G. Oppenheim ◽  
Richard A. Wahle
Keyword(s):  
Video Surveillance ◽  
Population Regulation ◽  
Gulf Of Maine ◽  
Homarus Americanus ◽  
Quantitative Information ◽  
Video Monitoring ◽  
Predatory Fish ◽  
American Lobster ◽  
Population Densities

We conducted tethering experiments in the field to evaluate day–night differences in the identity and frequency of predators encountered by the American lobster (Homarus americanus) in coastal Maine, USA. Separate daytime and nighttime deployments were conducted using tethered lobsters under infrared-illuminated video surveillance. Supplemental tethering trials without video surveillance provided further quantitative information on diel and size-specific predation patterns. We found crabs to be the most common predators during the day, whereas lobsters prevailed at night. Contrary to expectations, we measured higher predation rates at night than during the day, suggesting that nocturnal interactions with conspecifics may play a more important role in lobster population regulation than previously thought when lobster population densities are high and large predatory fish are rare. As large predatory groundfish have been depleted in the Gulf of Maine, lobster populations have reached historic highs, making density-dependent feedbacks such as cannibalism more likely.

scholarly journals Le mouvement coopératif

2005 ◽  
Vol 11 (3) ◽  
pp. 301-325
Author(s):  
Pierre-A. Bélanger
Keyword(s):  
Capital Social ◽  
Situation Économique ◽  
La Madeleine ◽  
Magdalen Islands

Le mouvement coopératif aux Iles-de-la-Madeleine est intéressant à plus d'un point de vue. Son premier intérêt vient sûrement du fait que son introduction provoque une coupure dans l'organisation économique des Iles. Le second vient du fait qu'en l'espace de vingt ans on le retrouve dans tous les secteurs: production, consommation, épargne et crédit, services (transport et électricité). Ce mode d'organisation économique a donc pris une grande ampleur. On trouve, aux Iles, huit associations coopératives de pêcheurs (A.C.P.) dont six sont affiliées à une centrale. Elles couvrent l'ensemble du territoire francophone. Fondées entre 1932 et 1943, elles ont 648 membres en 1964, dont 54.3% sont actifs. Mais leur situation économique, en 1964 toujours, est assez précaire: seulement 38.1% des membres ont payé le capital social souscrit. De plus, 84.9% des pêcheurs actifs sont endettés vis-à-vis leur coopérative; dans quatre coopératives, cette dette dépasse largement le capital social payé. Le profit fait sur le poisson a une importance très variable dans les sources de revenus des coopératives: il ne dépasse pas 75% et peut n'atteindre que 28%.2 On constate donc que la situation des coopératives de production n'est pas très florissante. Les magasins coopératifs se sont détachés des coopératives de production au cours des années '40. Il en existe quatre en 1968: le Magasin coopératif de Havre-aux-Maisons, L'Unité, de Lavernière, La Sociale de l'Étang-du-Nord et L’ Éveil de Fatima. En incluant les coopératives de pêcheurs à caractère mixte (production et consommation), le secteur coopératif de la consommation contrôle 75% du marché, selon un gérant. C'est le secteur le plus florissant de la coopération aux Iles-de-la-Madeleine. On trouve six Caisses populaires aux Iles; fondées entre 1937 et 1947, elles sont situées à Lavernière, Havre-aux-Maisons, Fatima, Bassin, Havre-Aubert et Grande-Entrée. Elles contrôlent une grande partie des transactions bancaires, n'ayant comme compétitrice qu'une succursale de la Banque Canadienne Nationale, située à Cap-aux-Meules. Deux coopératives de services ont été fondées aux Iles : une coopérative de transport et une coopérative d'électricité. La première, fondée en 1943, a le monopole du transport avec le Québec et entre en compétition avec la Magdalen Islands Transportation Co. (une filiale de la Clarke Steamship) pour les liaisons avec les Maritimes. La seconde a été fondée en 1950, à l'instigation de l'Office d'électrification rurale. Toutes deux sont des coopératives régionales.

Detection of the mRNA encoding vitellogenesis inhibiting hormone in neurosecretory cells of the X-organ in Homarus americanus by in situ hybridization

1992 ◽  
Vol 87 (3) ◽  
pp. 443-450 ◽  
Author(s):  
A-M. Laverdure ◽  
M. Breuzet ◽  
D. Soyez ◽  
J. Becker
Keyword(s):  
In Situ Hybridization ◽  
Homarus Americanus ◽  
Neurosecretory Cells

scholarly journals Egg Development Trajectories of Early and Late-Spawner Lobsters (Homarus Americanus) in the Magdalen Islands, Québec

2009 ◽  
Vol 29 (3) ◽  
pp. 356-363 ◽  
Author(s):  
Louise Gendron ◽  
Patrick Ouellet
Keyword(s):  
Homarus Americanus ◽  
Egg Development ◽  
Development Trajectories ◽  
Magdalen Islands

scholarly journals Estimates of in Situ Larval Development Time for the Lobster, Homarus Americanus

2007 ◽  
Vol 27 (3) ◽  
pp. 454-462 ◽  
Author(s):  
Eric R. Annis ◽  
Lewis S. Incze ◽  
Robert S. Steneck ◽  
Nicholas Wolff
Keyword(s):  
Larval Development ◽  
Development Time ◽  
Homarus Americanus
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