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.

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.

Dispersal of the sugar-cane scale Aulacaspis tegalensis (Zhnt.) (Hem., Diaspididae) by air currents

1972 ◽  
Vol 61 (3) ◽  
pp. 547-558 ◽  
Author(s):  
D. J. Greathead
Keyword(s):  
Sugar Cane ◽  
Laboratory Experiments ◽  
Sticky Trap ◽  
Research Station ◽  
High Humidity ◽  
Dispersal Mechanism ◽  
Large Numbers ◽  
Speed Up ◽  
Trap Catches ◽  
Aulacaspis Tegalensis

By means of sticky traps and a suction trap, it was demonstrated on a plot of sugar-cane at Kawanda Research Station, Uganda, that large numbers of crawlers of Aulacaspis tegalensis (Zhnt.) become airborne (up to 10/m3). The numbers increase with wind speed up to about 2·0 m/s and then remain constant, but are depressed by increasing humidity. In laboratory experiments, crawler survival was reduced by high temperatures (30°C) and low humidities (30% r.h.), but some individuals should survive the extreme conditions sometimes experienced if airborne from morning until evening. On hatching, crawlers move upwards and towards the light, but downwards in the dark; movement is inhibited by high humidity. These behaviour responses indicate hat the presence of crawlers in the air is not accidental but a dispersal mechanism. At Arusha Chini, an isolated sugar estate in Tanzania, sticky-trap catches downwind of a windbreak confirmed that airborne dispersal of crawlers is a major source of infestation. It is shown that air currents could have carried crawlers to Arusha Chini from a source on the Kenya coast, 260 km to the east.

Studies on the ecology of some temporary freshwater pools in Victoria with special reference to microcrustaceans

1977 ◽  
Vol 28 (4) ◽  
pp. 439 ◽  
Author(s):  
DW Morton ◽  
IAE Bayly
Keyword(s):  
High Probability ◽  
Calanoid Copepod ◽  
Shallow Waters ◽  
New Combinations ◽  
Common Occurrence ◽  
Chemical Parameters ◽  
Daphnia Carinata ◽  
Large Numbers ◽  
Three New Species ◽  
Ph Range

Fifty-three temporary freshwater pools (mean depth 23 cm) located mainly in eastern Victoria were studied from February to September 1973. Chemical parameters determined were pH (range 5.7-8.2, mean 6.9), conductivity (K18, range 55-5500, mean 340 �S/cm), dissolved oxygen (range 23-170, mean 72% saturation) and turbidity (range 2-310, mean 50 Formazin turbidity units). A total of 60 microcrustacean species was recorded. The Australasian endemic cladoceran, Saycia cooki (King), was of common occurrence from June through to August. The fact that it tends to reach peak numbers early in the life of a pool is probably related to the production of large numbers of ephippial eggs. In contrast, cladocera which produce only one or two ephippial eggs, such as Chydorus, Moina and Simocephalus, tend to appear later in succession. Simocephalus expinosus (benthic) and Daphnia carinata, s.l. (planktonic) had mutually exclusive distributions and are apparently unable to coexist in shallow waters. Endemic cyclopoid copepods encountered included three new species of Microcyclops, M. arnaudi (Sars), Acanthocyclops australis Sars, and Acanthocyclops, sp. nov. Like Saycia, Microcyclops varicans and Acanthocyclops bisetosus exhibited maximal numbers early in succession. Several new combinations of coexisting calanoid copepod species belonging to the genera Boeckella and Hemiboeckella are reported. Computer analysis showed that the following four groups of species had a high probability of co-occurrence: (1) Cypretta sp., Attheyella australica, Ilyodromus sp., Saycia cooki; (2) Cyprinotus leanus, Acanthocyclops bisetosus, Moina tenuicornis; (3) Boeckella major, B. pseudochelae, Cypris sp., Daphnia carinata, s.l. ; (4) Simocephalus exspinosus, Microcyclops varicans.

scholarly journals The gene-rich genome of the scallop Pecten maximus

GigaScience ◽  
2020 ◽  
Vol 9 (5) ◽  
Author(s):  
Nathan J Kenny ◽  
Shane A McCarthy ◽  
Olga Dudchenko ◽  
Katherine James ◽  
Emma Betteridge ◽  
...  
Keyword(s):  
Genome Assembly ◽  
Gene Annotation ◽  
Atlantic Coast ◽  
Shallow Waters ◽  
Pharmaceutical Companies ◽  
Marine Bivalve ◽  
Pecten Maximus ◽  
Assembly Sequence ◽  
Algal Toxins ◽  
Large Numbers

Abstract Background The king scallop, Pecten maximus, is distributed in shallow waters along the Atlantic coast of Europe. It forms the basis of a valuable commercial fishery and plays a key role in coastal ecosystems and food webs. Like other filter feeding bivalves it can accumulate potent phytotoxins, to which it has evolved some immunity. The molecular origins of this immunity are of interest to evolutionary biologists, pharmaceutical companies, and fisheries management. Findings Here we report the genome assembly of this species, conducted as part of the Wellcome Sanger 25 Genomes Project. This genome was assembled from PacBio reads and scaffolded with 10X Chromium and Hi-C data. Its 3,983 scaffolds have an N50 of 44.8 Mb (longest scaffold 60.1 Mb), with 92% of the assembly sequence contained in 19 scaffolds, corresponding to the 19 chromosomes found in this species. The total assembly spans 918.3 Mb and is the best-scaffolded marine bivalve genome published to date, exhibiting 95.5% recovery of the metazoan BUSCO set. Gene annotation resulted in 67,741 gene models. Analysis of gene content revealed large numbers of gene duplicates, as previously seen in bivalves, with little gene loss, in comparison with the sequenced genomes of other marine bivalve species. Conclusions The genome assembly of P. maximus and its annotated gene set provide a high-quality platform for studies on such disparate topics as shell biomineralization, pigmentation, vision, and resistance to algal toxins. As a result of our findings we highlight the sodium channel gene Nav1, known to confer resistance to saxitoxin and tetrodotoxin, as a candidate for further studies investigating immunity to domoic acid.

Sex-biased trap capture and odor-stimulated upwind flight in the field by Rhagoletis mendax (Diptera: Tephritidae)

2001 ◽  
Vol 133 (2) ◽  
pp. 293-295 ◽  
Author(s):  
L.P.S. Kuenen ◽  
P.J. Silk
Keyword(s):  
Sex Ratio ◽  
Food Availability ◽  
Insect Pest ◽  
Cultural Control ◽  
Orientation Behavior ◽  
Eastern Canada ◽  
Vaccinium Angustifolium ◽  
Sticky Traps ◽  
Rhagoletis Mendax ◽  
Wind Vane

The bluebeny maggot, Rhagoletis mendax Curran, is a primary insect pest of low bush blueberries, Vaccinium angustifolium Ait. (Ericaceae), in eastern Canada. Eggs are laid in ripening berries and mature larvae emerge from the berries to pupate in the soil. Adult flies can be controlled with insecticides (Wood et al. 1983) and (or) cultural control by bum or flail-mow pruning of bushes. Pruned plants do not bear fruit the season after pruning, and this rotation of fruit and nonfruit years is believed to reduce fly populations by limiting food availability (Lathrop 1952). Adult flies can be monitored by capture on yellow-panel sticky traps or red-sphere traps (Prokopy and Coli 1978; Wood et al. 1983; Neilson et al. 1984). In this study, we focused on the sex ratio of R. mendax flies captured on baited and unbaited yellow-panel sticky traps (Pheroco® AM traps) and on the orientation behavior of flies toward wind-vane traps.

scholarly journals Evidence of Differential Migration by Sex in White-Throated Sparrows (Zonotrichia Albicollis)

The Auk ◽  
2002 ◽  
Vol 119 (2) ◽  
pp. 539-543 ◽  
Author(s):  
Kendell D. Jenkins ◽  
Daniel A. Cristol
Keyword(s):  
United States ◽  
Sex Ratio ◽  
Southern United States ◽  
Museum Specimens ◽  
Differential Migration ◽  
Zonotrichia Albicollis ◽  
Winter Range ◽  
Broad Agreement ◽  
Large Numbers ◽  
Atlantic Flyway

Abstract Differential migrants are species in which one population class migrates farther than another. White-throated sparrows (Zonotrichia albicollis), which migrate into the southern United States each autumn in large numbers, have been proposed as a candidate differential migrant (Cristol et al. 1999). Using Bird Banding Lab data, we tested for latitudinal variation in the sex ratio of White-throated Sparrows in the Atlantic and central flyways. We found that the proportion of females increases with decreasing latitude in at least the Atlantic flyway, strongly suggesting that females migrate farther than males. Sex ratios calculated from those banding data were compared to those of museum specimens collected at the same latitudes, as well as single-season population samples at three latitudes in the heart of the winter range. Broad agreement was found using the three independent methods of sampling the sex ratio, so we conclude that White-throated Sparrows are differential migrants.

Seasonal patterns in trap catches of the crayfish Cambarus bartoni and Orconectes virilis in six south-central Ontario lakes

1993 ◽  
Vol 71 (6) ◽  
pp. 1136-1145 ◽  
Author(s):  
Keith M. Somers ◽  
Roger H. Green
Keyword(s):  
Water Temperature ◽  
Relative Abundance ◽  
Sampling Period ◽  
Smallmouth Bass ◽  
Orconectes Virilis ◽  
Scuba Divers ◽  
South Central ◽  
Baited Traps ◽  
Trap Catches ◽  
Physical And Chemical

Crayfish were trapped in six south-central Ontario lakes to examine seasonal changes in estimates of relative abundance. Baited-trap catches of Cambarus bartoni and Orconectes virilis correlated with changes in water temperature. Cambarid catches increased in the spring until a midsummer maximum, but dropped suddenly as the water temperature began to fall in August. Ovigerous (i.e., egg-bearing) females and recently moulted males were captured by SCUBA divers in August. Trap catches increased, once breeding and moulting periods concluded, and subsequently decreased as water temperatures continued to drop in the autumn. In contrast, catches of male O. virilis increased in the spring and remained relatively constant throughout the summer until water temperatures fell in September. Catches of female O. virilis peaked somewhat later in the summer and then gradually declined in the early fall. Although the two species and the two sexes differed in the length of the midsummer sampling period when trap catches were relatively constant, similar seasonal trends among lakes suggest that midsummer trap catches can be used to estimate crayfish relative abundance. Other factors, such as the presence of smallmouth bass (Micropterus dolomieui), lake physical and chemical characteristics, and the number of co-occurring crayfish species also correlated with trap catches. Both the presence of bass and the number of co-occurring species of crayfish probably affect crayfish behaviour and activity, thereby reducing catches in baited traps, but not necessarily affecting actual population abundance. Comparisons of relative abundance based on catches from baited traps must control for these seasonal behavioural, and environmental factors.

Lithocolletis blancardella Fabricius (Lepidoptera: Gracilariidae) on Apple in Eastern North America with Notes on Other Species Occurring on Rosaceae

1964 ◽  
Vol 96 (11) ◽  
pp. 1442-1449 ◽  
Author(s):  
H. T. Stultz
Keyword(s):  
United States ◽  
North America ◽  
Leaf Miner ◽  
Eastern North America ◽  
Similar Species ◽  
Black Cherry ◽  
Northeastern United States ◽  
Maritime Provinces ◽  
Eastern Canada ◽  
Large Numbers

AbstractA spotted tentiform leaf miner, often present during recent years in large numbers in apple orchards in the Maritime Provinces of Canada, is identified as Lithocolletis blancardella Fabr., a species common on apples in Europe. Recent collecting indicates that the species occurs widely in Eastern Canada and the northeastern United States. Diagnostic characters, especially those of the male genitalia, are compared with those of specimens identified as L. crataegella Clem. and L. propinquinella Braun, two similar species which commonly occur on apple and black cherry respectively.

Anonyx sarsi: a major unrecognized scavenger and predator in the intertidal zone

1999 ◽  
Vol 79 (6) ◽  
pp. 1127-1128 ◽  
Author(s):  
A. Ingólfsson ◽  
I. Agnarsson
Keyword(s):  
Intertidal Zone ◽  
Shallow Waters ◽  
Large Numbers ◽  
Baited Traps ◽  
Important Predator

Anonyx sarsi (Crustacea: Amphipoda) is a widely distributed scavenger and predator in shallow waters of northern seas. It was caught, often in large numbers, in baited traps in the intertidal in Iceland, especially during mid-winter. Although hitherto only sporadically recorded from the intertidal, the species is undoubtedly among the most important carrion feeders there, and probably an important predator as well.

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