Salinity tolerance in the early larval stages of Carcinus maenas (Decapoda, Brachyura), a recent invader of the Bras d'Or lakes, Nova Scotia, Canada

Crustaceana ◽  
2007 ◽  
Vol 80 (4) ◽  
pp. 475-490 ◽  
Author(s):  
Monica Bravo ◽  
Anna Metaxas ◽  
Beth Cameron
Keyword(s):  
Nova Scotia ◽  
Salinity Tolerance ◽  
Carcinus Maenas ◽  
Larval Stages

Observations on the Spread of Cyzenis albicans (Fall.) (Tachinidae: Diptera), an Introduced Parasite of the Winter Moth, Operophtera brumata (L.), (Geometridae: Lepidoptera), in Nova Scotia

1960 ◽  
Vol 92 (11) ◽  
pp. 862-864 ◽  
Author(s):  
D. G. Embree
Keyword(s):  
Nova Scotia ◽  
Control Measure ◽  
Operophtera Brumata ◽  
Winter Moth ◽  
Larval Stages

Cyzenis albicans (Fall.) has been introduced into Nova Scotia as a control measure against the winter moth, Operophtera brumata (L.). The parasite attacks the late larval stages of the winter moth, pupates within the host in the ground, and emerges in the spring. The first liberations were made at Oak Hill near Bridgewater and the dates of releases as well as the numbers released were reported by Graham (1958) as follows: 1954, 31; 1955, 1008; 1956, 1005; 1957, 250. Graham made recoveries of C. albicans from rearings of larvae collected at Oak Hill in 1956 and 1957 and found that parasitism was less than two per cent both years. While liberations have been made at other locations in the Province since 1957, no further releases have been made at or near Oak Hill.

Drastic decline of an extensive eelgrass bed in Nova Scotia due to the activity of the invasive green crab (Carcinus maenas)

2013 ◽  
Vol 161 (1) ◽  
pp. 3-15 ◽  
Author(s):  
David J. Garbary ◽  
Anthony G. Miller ◽  
Jim Williams ◽  
Norm R. Seymour
Keyword(s):  
Nova Scotia ◽  
Carcinus Maenas ◽  
Green Crab

Morphometrics and estimates of force generation by the chelae of a North American population of the invasive green crab, Carcinus maenas (L.)

2003 ◽  
Vol 81 (2) ◽  
pp. 203-215 ◽  
Author(s):  
S C Mitchell ◽  
S M Kennedy ◽  
P J Williams ◽  
M E DeMont
Keyword(s):  
Nova Scotia ◽  
Carcinus Maenas ◽  
European Population ◽  
Force Generation ◽  
Green Crab ◽  
North American Population ◽  
Female Crab ◽  
Lever System ◽  
Predation Effects ◽  
Prey Handling

The European green crab, Carcinus maenas, is an invasive species in eastern North America and has the potential to significantly impact wild and aquaculture shellfish in the southern Gulf of St. Lawrence, Canada. To examine potential predation effects on local shellfish and assess the appropriateness of extrapolating results from studies conducted elsewhere, the morphometry of chelae from a recently established population of C. maenas in Nova Scotia was examined for comparison with the presumed founding (European) population, and forces generated by the chelae over a range of crab sizes were estimated. The Nova Scotia population was found to be morphologically very similar to European populations with respect to chela structure. Force generation by the chelae was found to scale with isometry in the female crab and with positive allometry in the male. Estimated forces compare well with previously reported forces, and force generation is calculated to increase in a nonlinear manner proceeding from the chela tips proximally toward the fulcrum. The calculated forces generated by the chelae are clearly sufficient for outright crushing of some shells (e.g., Mya arenaria), even for small crabs, but appear to be too low for crushing those of other molluscs. There is a complex interplay between gape and maximum force along the length of the dactyl that allows great variability in force application, and thus also in the size of prey consumed and prey-handling behaviour. We suggest that for such a lever system, the gape angle of the chelae, which does not change with crab size, is optimal with respect to the resultant force generated.

Invasive green crab, Carcinus maenas, on the Atlantic coast and in the Bras d'Or Lakes of Nova Scotia, Canada: larval supply and recruitment

2005 ◽  
Vol 85 (4) ◽  
pp. 847-855 ◽  
Author(s):  
Beth Cameron ◽  
Anna Metaxas
Keyword(s):  
Nova Scotia ◽  
Atlantic Coast ◽  
Carapace Width ◽  
Carcinus Maenas ◽  
Green Crab ◽  
Larval Supply ◽  
Surface Salinity ◽  
Life History Stages ◽  
European Green Crab ◽  
Tidal Signal

Patterns in larval supply and recruitment of the invasive European green crab, Carcinus maenas, were examined at two sites in Nova Scotia, Canada: a typical Atlantic coastal site with high salinity (∼33) and strong tidal signal (Terence Bay); and a microtidal site in the Bras d'Or Lakes, where surface salinity fluctuated from 0 to 23 (Benacadie Pond). Abundance of all life history stages (zoeae, megalopae, juveniles and ovigerous females) was sampled approximately biweekly at each site from June 2001 to June 2002. The reproductive season, based on the presence of ovigerous females, is ∼5 months (June to October) at both sites. Zoeae-I were collected from June to July 2001 and in June 2002 at Terence Bay, and from June to August 2001 at Benacadie Pond. We did not collect later zoeal stages at either site. Megalopae were collected from September to October 2001 at Terence Bay, and from August to September 2001 at Benacadie Pond. Juveniles 1–6 mm carapace width (CW) were present throughout the summer at Terence Bay, and only in autumn at Benacadie. Juveniles 6–12 and 12–27 mm CW were present throughout the summer and autumn at both sites. At Terence Bay, densities of 1–6 and 12–27 mm CW juveniles did not vary among intertidal zones. In contrast, the 6–12 mm CW size-class appeared to move higher in the intertidal through the season, possibly due to effects of predation.

Distribution and rhythmic locomotor patterns of estuarine and open-shore populations of Carcinus maenas

1992 ◽  
Vol 72 (3) ◽  
pp. 599-609 ◽  
Author(s):  
I. J. McGaw ◽  
E. Naylor
Keyword(s):  
Locomotor Activity ◽  
Salinity Tolerance ◽  
Prolonged Exposure ◽  
Carcinus Maenas ◽  
Salinity Change ◽  
Low Salinity ◽  
Salinity Reduction ◽  
Locomotor Patterns

Populations of Carcinus maenas (Crustacea: Decapoda) from an estuary and from the open shore were compared for salinity tolerance and rhythmic locomotor activity. Estuarine crabs were shown to be predominantly green; red and orange individuals were rare within the estuary in contrast to the open shore. Red crabs were less able to tolerate prolonged exposure to low salinity than green crabs. Spontaneous circatidal rhythms of locomotor activity were similar in red and green forms, but red crabs from the open shore reacted earlier, and were more active upon salinity reduction, than green crabs from the estuary which also showed rapid habituation to episodes of salinity change.

Salinity Tolerance in Color Phases of Female Green Crabs, Carcinus Maenas (Linnaeus, 1758)

Crustaceana ◽  
2003 ◽  
Vol 76 (2) ◽  
pp. 247-253 ◽  
Author(s):  
Aly McKnight ◽  
Karen Kellogg ◽  
Karen Lee ◽  
Francis Juanes
Keyword(s):  
Salinity Tolerance ◽  
Carcinus Maenas

Factors Influencing the Size of American Lobster (Homarus americanus) Stocks Along the Atlantic Coast of Nova Scotia, Gulf of St. Lawrence, and Gulf of Maine: A New Synthesis

1983 ◽  
Vol 40 (2) ◽  
pp. 168-184 ◽  
Author(s):  
Gareth C. Harding ◽  
Ken F. Drinkwater ◽  
W. Peter Vass
Keyword(s):  
Nova Scotia ◽  
Gulf Of Maine ◽  
Rapid Development ◽  
Atlantic Coast ◽  
Homarus Americanus ◽  
American Lobster ◽  
Georges Bank ◽  
Larval Recruitment ◽  
Larval Stages ◽  
Recruitment Failure

The general aspects of fluctuating American lobster (Homarus americanus) stocks are considered in an attempt to identify common principles controlling lobster populations in the Gulf of Maine, Gulf of St. Lawrence, and the Atlantic coast of Nova Scotia. Inshore fishing mortality is known to be precariously high in both Canadian and American waters yet only in the central Northumberland Strait region and along the Atlantic coast of Nova Scotia are stocks experiencing steep declines. Existing regulations allow fishing of lobsters well below the size at which maturity can be expressed. In western and central Northumberland Strait female lobsters are not protected by the 'berried' law because of the timing of the fishing season. Climatic change, expressed as sea-surface temperature, is closely associated with the success of lobster recruitment in the Gulf of Maine, but nowhere else. Huntsman's hypothesis that warm surface water of sufficient duration is essential for the successful completion of the larval stages of the lobster is found to have wide application. Warmer waters are also found to have a preponderance of plankton in the size categories required for feeding by the first two larval stages. Both the southern Gulf of St. Lawrence and the southwestern Gulf of Maine, including Georges Bank, are believed to be prolific nursery grounds for the early larval lobsters because warm water with plenty of food stimulates rapid development and settling. We calculated that larvae released on Georges Bank supply recruits to southern Nova Scotia, Bay of Fundy, and Maine, whereas some larvae from the southern Gulf of St. Lawrence are thought to settle as far as Cape Breton Co., N.S., and before the closure of the Strait of Canso, Guysborough Co., N.S. The past importance of lobster recruitment to the Atlantic coast of Nova Scotia through the Strait of Canso is estimated to have been as high as 60% of the average landings in Chedabucto Bay during the 11 best years of this fishery. The failure of the Atlantic coast lobster fishery off Nova Scotia is believed to have been initiated by a larval recruitment failure caused by the synchronous closure of the Strait of Canso and the start of a general climatic cooling. Possibly a critical temperature was reached along the Atlantic coast of Nova Scotia in the 1950s below which larval survival is much reduced by the shortened season. Reduced lobster abundance along the Atlantic coast of Nova Scotia may have contributed to the imbalance in the benthic ecosystem in which an uncontrolled urchin population consumed the kelp beds and until recently greatly reduced the primary production input to the system.Key words: American lobster, Homarus americanus; stocks, recruitment, ecology, larval transport

Metazoan parasites and commensals of five crab (Brachyura) species from eastern Canada

1985 ◽  
Vol 63 (9) ◽  
pp. 2224-2229 ◽  
Author(s):  
John Brattey ◽  
Robert W. Elner ◽  
Leslie S. Uhazy ◽  
Anne E. Bagnall
Keyword(s):  
Carcinus Maenas ◽  
Eastern Canada ◽  
Cancer Borealis ◽  
New Host ◽  
Metazoan Parasites ◽  
Larval Stages ◽  
Cancer Irroratus ◽  
Diverse Community ◽  
New Host Records ◽  
Larval Parasites

Seven hundred and twenty-one brachyuran crabs (Cancer borealis, Cancer irroratus, Carcinus maenas, Chionoecetes opilio, Geryon quinquedens) were collected in waters off eastern Canada during 1980–1982 and the prevalences of metazoan parasites and commensals determined. The survey revealed larval stages of three species of parasite, Microphallus sp. (Platyhelminthes: Digenea), Polymorphus sp. (Acanthocephala: Palaeacanthocephala), Nectonema sp. (Nematomorpha: Nectonematoidea), and five species of ectocommensal, Eteonopsis geryonicola (Annelida: Polychaeta), Johanssonia arctica (Annelida: Hirudinea), Ectocotyla paguri and Ectocotyla multitesticulata (Platyhelminthes: Turbellaria), and Carcinonemertes sp. (Nemertea: Monostilifera). New host records are reported for E. geryonicola in the branchial chambers of C. opilio and for Carcinonemertes sp. on egg masses of ovigerous G. quinquedens. All of the larval parasites, except Nectonema sp., and all of the ectocommensals, except J. arctica and Ectocotyla spp., are previously unreported from crabs off eastern Canada. Our findings suggest that the crab species studied do not support a diverse community of metazoan parasites or commensals.

scholarly journals Absence of recovery in a degraded eelgrass (Zostera Marina) bed in Nova Scotia, Canada: Results from a transplant study

2020 ◽  
Vol 50 (2) ◽  
pp. 251
Author(s):  
Erin Wilson ◽  
David J. Garbary
Keyword(s):  
Nova Scotia ◽  
Zostera Marina ◽  
Light Attenuation ◽  
Carcinus Maenas ◽  
Control Site ◽  
Green Crab ◽  
Eastern Canada ◽  
Growth And Survival ◽  
Negative Effect ◽  
European Green Crab

By the early 2000s, the invasion of the European green crab (Carcinus maenas) had caused a severe decline of eelgrass (Zostera marina) beds in eastern Canada. The formerly lush eelgrass bed in Benoit Cove, Nova Scotia, was extirpated by 2009 and has subsequently failed to recover. The objective of our study was to establish if Benoit Cove (BC) has reached a new equilibrium in which eelgrass cannot recolonize. From July 3 - August 29, 2018, we transplanted eelgrass using frames and monitored eelgrass growth and survival relative to the nearby donor (control) site in Tracadie West Arm (TWA) that had an extensive eelgrass meadow with over 95% cover. Transplant survival was 91.6% and 15.4% for TWA and BC, respectively (P < 0.001). Above-ground growth declined at both sites, and could be associated with high summer water temperatures and/or extreme epiphytism. Sediments at both sites had high silt composition (> 28%), and the absence of a macrophyte canopy lead to increased light attenuation in BC in moderate wind and tidal currents. The low density of green crabs in both BC and TWA (0.01 m-2 and 0.08 m-2, respectively), and the apparently healthy eelgrass bed in TWA, suggest that green crabs are not having a negative effect on eelgrass in this system and are not responsible for the lack of recolonization of eelgrass in BC.Keywords: Atlantic Canada; eelgrass bed; European green crab; transplant; Zostera marina

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