Migratory Movements of Ovigerous Lobsters, Homarus americanus, Tagged off Grand Manan, Eastern Canada

1986 ◽  
Vol 43 (11) ◽  
pp. 2197-2205 ◽  
Author(s):  
Alan Campbell
Keyword(s):  
Homarus Americanus ◽  
Shallow Waters ◽  
Bay Of Fundy ◽  
Degree Days ◽  
Eastern Canada ◽  
Egg Development ◽  
Sufficient Degree ◽  
Positive Correlations ◽  
Hatching Eggs ◽  
Migratory Movements

A total of 2139 ovigerous lobsters, Homarus americanus, were tagged and egg development recorded off Grand Manan, eastern Canada, during 1982–83. Recaptures during August 1982 to January 1984 totaled 1877, representing 1046 individuals including 457 that were captured 2–10 times. The single recapture data indicate that the majority (75%) of the lobsters moved < 15 km. Use of distance moved information from single recaptures of lobsters at liberty for long periods can be misleading, since exact distance moved between tag release–recapture points usually is unknown. Multiple recapture and depth at recapture data gave more information on the movements of the lobsters. Many lobsters showed seasonal shallow-deep migrations of > 20 km with recaptures in shallow (< 20 m) water during summer–fall and in deep (> 200 m) water during winter–spring. Many ovigerous females returned to the Grand Manan area the following summer. A few (7%) moved north > 30 km into the Bay of Fundy and south as much as 322 km along the coastline of Maine. Examination of the multiple recapture data between months indicated positive correlations between change in depth, distance moved, and water temperature. The seasonal depth migrations of ovigerous lobsters appear to be associated with maximizing temperatures which provide sufficient degree-days for completion of egg development. Also, hatching eggs in relatively warm shallow waters may confer a survival advantage for pelagic lobster larvae by decreasing development time to the benthic stage.

Aggregations of Berried Lobsters (Homatus americanus) in Shallow Waters off Grand Manan, Eastern Canada

1990 ◽  
Vol 47 (3) ◽  
pp. 520-523 ◽  
Author(s):  
Alan Campbell
Keyword(s):  
Sex Ratio ◽  
Larval Dispersal ◽  
Shallow Waters ◽  
Eastern Canada ◽  
Egg Development ◽  
Scuba Divers ◽  
Large Numbers ◽  
Shallow Area ◽  
Newly Hatched Larvae ◽  
Trap Catches

The relative abundance, size, and sex frequencies of trap-caught lobsters were determined from five areas near the northern end of Grand Manan during August–September 1982 and August 1983. Large numbers of berried (ovigerous) females (90/100 trap hauls) and few male or nonberried female lobsters were caught in shallow (1–22 m) depths close to the shoreline in one area. The sex ratio was near 50% males in deeper areas. In the shallow area SCUBA divers observed mature lobsters excavating bowl-shaped depressions in the sand-clay substrate and confirmed the high density of berried females indicated by the trap catches. Berried females may seek and congregate in areas favourable for egg development and larval dispersal. During summer, shallow areas provide warmer water than deeper areas and therefore allow faster egg development and egg extrusion. Also, the shallow waters with strong tidal currents would allow rapid dispersal of newly hatched larvae.

Multiple Fertilization and Consecutive Spawning in Large American Lobsters, Homarus americanus

1986 ◽  
Vol 43 (11) ◽  
pp. 2291-2294 ◽  
Author(s):  
S. L. Waddy ◽  
D. E. Aiken
Keyword(s):  
Body Size ◽  
Carapace Length ◽  
Homarus Americanus ◽  
Large Female ◽  
Bay Of Fundy ◽  
Relative Fecundity ◽  
Logarithmic Relationship

Large female American lobsters, Homarus americanus (> 120 mm carapace length), maintained at nearshore Bay of Fundy temperatures often spawn twice without an intervening molt (consecutive spawning). Consecutive spawning occurs in two forms: successive-year (spawning in two successive summers, a molt in the first and fourth years) and alternate-year (spawning in alternate summers, a molt in the first and fifth years). In both types, females often are able to fertilize the two successive broods with the sperm from a single insemination (multiple fertilization). Twenty of 21 large females that were held for up to 13 yr displayed one of these types of consecutive spawning. Consecutive spawning and multiple fertilization enable large lobsters to spawn more frequently over the long term than their smaller counterparts. This, combined with the logarithmic relationship between body size and numbers of eggs produced, means that very large lobsters have a much greater relative fecundity than previously thought.

Marine tube-dwelling diatoms of eastern Canada: descriptions, checklist, and illustrated key

1984 ◽  
Vol 62 (4) ◽  
pp. 778-794 ◽  
Author(s):  
Christopher S. Lobban
Keyword(s):  
New Species ◽  
Northwest Territories ◽  
Common Species ◽  
Bay Of Fundy ◽  
Eastern Canada ◽  
Lawrence Estuary ◽  
The Common ◽  
Living Material ◽  
St Lawrence Estuary ◽  
A New Species

From a study of living materials and specimens in several regional herbaria, a list has been drawn up of all the common and several of the rarer tube-dwelling diatoms of eastern Canada. Descriptions, illustrations of living material and acid-cleaned valves, and a key to the species are provided. Most specimens were from the Atlantic Provinces and the St. Lawrence estuary, but a few were from the Northwest Territories. By far the most common species is Berkeleya rutilans. Other species occurring commonly in the Quoddy Region of the Bay of Fundy, and sporadically in space and time elsewhere, arc Navicula delognei (two forms), Nav. pseudocomoides, Nav. smithii, Haslea crucigera, and a new species, Nav.rusticensis. Navicula ramosissima and Nav. mollis in eastern Canada are usually found as scattered cohabitants in tubes of other species. Nitzschia tubicola and Nz. fontifuga also occur sporadically as cohabitants.

scholarly journals New records and AMS radiocarbon dates on Quaternary Walrus ( Odobenus Rosmarus ) from New Brunswick

2002 ◽  
Vol 51 (1) ◽  
pp. 107-111 ◽  
Author(s):  
Randall F. Miller
Keyword(s):  
New Brunswick ◽  
New Records ◽  
Temporal Distribution ◽  
Late Glacial ◽  
Bay Of Fundy ◽  
Eastern Canada ◽  
Radiocarbon Dates ◽  
Odobenus Rosmarus ◽  
Sand And Gravel ◽  
Past Summer

Abstract Walrus fossils are occasionally recovered during scallop dragging in the Bay of Fundy and from sand and gravel deposits along the coastline of New Brunswick in eastern Canada. Six new fossils and four new AMS radiocarbon dates significantly increase the information concerning late-glacial to postglacial walrus in New Brunswick. Dates range from about 12 800 BP to 2 900 BP, almost half falling between 9 000 and 10 000 BP. Temporal distribution of walrus, compared to estimates of past summer sea surface temperature, suggest that in the Bay of Fundy walrus occurred in waters ranging from 12 to 15° C.

Degree-day models to predict carrot weevil (Coleoptera: Curculionidae) emergence and oviposition in Nova Scotia, Canada

2020 ◽  
Vol 152 (3) ◽  
pp. 374-388
Author(s):  
Suzanne Blatt ◽  
Deney Augustine Joseph ◽  
G. Christopher Cutler ◽  
A. Randall Olson ◽  
Scott White
Keyword(s):  
Nova Scotia ◽  
Adult Emergence ◽  
Hill Equation ◽  
Base Temperature ◽  
Degree Days ◽  
Eastern Canada ◽  
Leaf Stage ◽  
True Leaf ◽  
Listronotus Oregonensis ◽  
Carrot Weevil

AbstractCarrot weevil, Listronotus oregonensis (LeConte) (Coleoptera: Curculionidae), is a pest of carrot (Daucus carota var. sativus Hoffmann; Apiaceae) throughout eastern Canada. Carrot weevil emergence and oviposition were monitored in commercial carrot fields in Nova Scotia. Cumulative degree days were calculated using a base temperature of 7 °C (DD7), and models were developed to predict cumulative emergence and oviposition using nonlinear regression. Cumulative emergence and oviposition were adequately explained as functions of DD7 by a three-parameter sigmoidal Hill equation. Our emergence model predicted initial and peak adult emergence at 35 and 387 DD7, respectively, with oviposition on carrot baits occurring as early as 42 DD7. Models were then validated to evaluate how well they performed. Oviposition on carrot plants began at the fourth true-leaf stage (342 DD7) and continued until eleventh true-leaf stage. Growers using these models can identify their window of opportunity to manage their carrot weevil populations targeting the majority of emerged adults before oviposition begins in the field.

Evidence for thermally mediated settlement in lobster larvae (Homarus americanus)

2013 ◽  
Vol 70 (11) ◽  
pp. 1641-1649 ◽  
Author(s):  
Eric R. Annis ◽  
Carl J. Wilson ◽  
Robert Russell ◽  
Philip O. Yund
Keyword(s):  
Water Temperature ◽  
Settlement Patterns ◽  
Coastal Region ◽  
Homarus Americanus ◽  
Size Increase ◽  
Coastal Current ◽  
Bottom Temperature ◽  
Degree Days ◽  
Successful Recruitment ◽  
Behavioral Avoidance

We examined the potential for bottom temperatures ≤12 °C to inhibit successful recruitment of planktonic lobster postlarvae to the benthos. In laboratory trials, postlarvae held at 11 °C exhibited higher mortality, slower development, and reduced size increase at molt relative to postlarvae held at 13 °C. We sampled at field sites within Machias Bay, Maine (mean bottom temperature 12.39 °C, 46.1 degree-days ≥12 °C) and at the mouth of the bay (mean bottom temperature 11.57 °C, 5.1 degree-days ≥12 °C), where temperature was influenced by the cold Eastern Maine Coastal Current (EMCC). We found significantly higher settlement at the warm inshore site but, the abundance of competent planktonic postlarvae was not significantly different between sites, indicating a disconnect between postlarval abundance and settlement. Regional sampling of newly settled lobsters revealed a pattern of higher settlement at inshore sites extending across a broader coastal region impacted by the EMCC. Our results suggest that small differences in water temperature may shape settlement patterns through either behavioral avoidance of colder settlement sites or elevated postsettlement mortality of postlarvae settling at colder sites.

Movements of lobsters (Homarus americanus) tagged in the Bay of Fundy, Canada

1986 ◽  
Vol 92 (3) ◽  
pp. 393-404 ◽  
Author(s):  
A. Campbell ◽  
A. B. Stasko
Keyword(s):  
Homarus Americanus ◽  
Bay Of Fundy
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