Some Life History Aspects of the Rock Crab, Cancer irroratus, in the Gulf of Maine

1972 ◽  
Vol 29 (10) ◽  
pp. 1479-1482 ◽  
Author(s):  
Jay S. Krouse
Keyword(s):  
Life History ◽  
Sexual Maturity ◽  
Size Range ◽  
Gulf Of Maine ◽  
Carapace Width ◽  
Early Spring ◽  
Late Winter ◽  
Early Winter ◽  
Cancer Irroratus ◽  
Rock Crab

Rock crabs, Cancer irroratus, were caught in wire lobster traps from 1968 through 1971 at Boothbay Harbor and in 1969 at Casco Bay, Maine. Females dominated the annual catches (except in Casco Bay) and width classes from 61 to 90 mm; while males were predominant above this size range. Rock crabs from Casco Bay were heavier at a given width than those from Boothbay Harbor. Soft-shelled females were caught mostly in the fall, while soft-shelled males appeared most frequently in late winter and early spring. The occurrence of newly berried females suggested that spawning (egg extrusion) took place in late fall and early winter, and hatching occurred in spring. Most female crabs attained sexual maturity between 70–80 mm carapace width, but a few matured at widths less than 70 mm.

Surfacing on Ice of Frozen-In Marine Bottom Materials

1974 ◽  
Vol 31 (7) ◽  
pp. 1195-1200 ◽  
Author(s):  
J. C. Medcof ◽  
M. L. H. Thomas
Keyword(s):  
Bottom Sediment ◽  
Direct Contact ◽  
Maximum Size ◽  
Lower Surface ◽  
Early Spring ◽  
Late Winter ◽  
Bay Of Fundy ◽  
Early Winter ◽  
M 10 ◽  
Fast Ice

In late winter and early spring, benthic materials have been observed in patches (maximum size 400 m × 10 m) on the surface of thick fast ice. They parallel the shores of estuaries and are commonest in the southern Gulf of St. Lawrence. Materials in the patches are often in strikingly natural postures and include layers of bottom sediment and plants and animals (eelgrass, shellfish [infauna and epifauna] starfish, flounders, and sticklebacks). Apparently these are frozen to the lower surface of the ice in early winter at low tides, when ice comes in direct contact with them. When the tide rises, the ice floats and raises frozen-on materials with it. Thereafter, the floating ice is thickened by freezing of water to its lower surface, and the bottom materials are thus frozen in between two layers of ice. At the same time the ice above the frozen-in materials is thinned by ablation (sublimation and melting) at its upper surface. Eventually the benthic materials are exposed on the surface of the ice. Allied phenomena have been observed in the Bay of Fundy region. Antarctica is the only other place where this has been reported to occur regularly. These phenomena and conditions favoring their occurrence in the two areas are compared.

The winter treatment of grapevines with zinc and its interaction with time of pruning

1964 ◽  
Vol 4 (14) ◽  
pp. 241 ◽  
Author(s):  
BG Coombe
Keyword(s):  
Zinc Sulphate ◽  
Field Experiments ◽  
Early Spring ◽  
Late Winter ◽  
Early Winter ◽  
Zinc Treatment ◽  
One Year ◽  
June July

Field experiments on dormant Sultana vines showed that yields were increased by applying zinc sulphate solutions immediately after pruning. Treatment by the swabbing of pruning cuts gave similar results to a cover spray. Increasing the concentration of zinc sulphate (up to the maximum tested-35 per cent) increased yield and no bud injury was seen. A delay of a day or more between pruning and treatment drastically reduced its effectiveness. Shorter intervals were tested but the results fluctuated ; a possible reason for this is discussed. The movement of zinc along Sultana canes was gauged by analysis of sections of cane cut up at varying times after swabbing the pruned end. In one year zinc moved at least 20 inches within two days, whereas, in another, it moved only 10 inches after one month. The yield of Grenache vines was increased when pruning was delayed from early winter until late winter and early spring. Zinc treatment increased yields in vines pruned in June, July, and August, but depressed yields when applied to vines pruned in September.

Some Estimates of Population Density and Feeding Habits of the Rock Crab, Cancer irroratus, in a Kelp Bed in Nova Scotia

1982 ◽  
Vol 39 (4) ◽  
pp. 636-639 ◽  
Author(s):  
N. C. Drummond-Davis ◽  
K. H. Mann ◽  
R. A. Pottle
Keyword(s):  
Nova Scotia ◽  
Population Density ◽  
Sea Urchins ◽  
Feeding Habits ◽  
Atlantic Coast ◽  
Carapace Width ◽  
Hermit Crabs ◽  
Cancer Irroratus ◽  
Kelp Bed ◽  
Rock Crab

The population density of rock crabs (Cancer irroratus) in a kelp bed on the Atlantic coast of Nova Scotia was examined by mark–recapture techniques and found to be about one crab (> 45-mm carapace width) per 2 square metres. Prey taken by the crabs included hermit crabs (Pagurus), mussels (Mytilus), sea urchins (Strongylocentrotus), and various small crustaceans and polychaetes. It was concluded that the crab population would exert a strong predation pressure on these invertebrates.Key words: Cancer irroratus, rock crabs, predation, population density, kelp

Extended seasonal occurrence of humpback whales in Massachusetts Bay

2013 ◽  
Vol 94 (6) ◽  
pp. 1117-1125 ◽  
Author(s):  
Anita Murray ◽  
Aaron N. Rice ◽  
Christopher W. Clark
Keyword(s):  
Gulf Of Maine ◽  
Humpback Whale ◽  
Acoustic Monitoring ◽  
Early Spring ◽  
Humpback Whales ◽  
Massachusetts Bay ◽  
Early Winter ◽  
Passive Acoustic Monitoring ◽  
Migratory Patterns ◽  
Passive Acoustic

Humpback whales (Megaptera novaeangliae) are known to utilize Massachusetts Bay as a feeding ground in the spring and summer, during the annual migration of the Gulf of Maine sub-population. However, there is a limited understanding of the pattern of humpback whale occurrence in this region outside of the feeding period. Passive acoustic monitoring of Massachusetts Bay over a two-year period, revealed an extended presence of acoustically active humpback whales throughout a majority of the study period (87%; 633 days of presence out of 725 days of acoustic monitoring). Humpback whale presence oscillated between lengthy periods of consistent presence (April to December) and relatively shorter periods of variable presence (December to March). Seasonal variation in presence was evident during three distinct phases: (1) maximum-presence from spring to early winter; (2) variable-presence in early winter and early spring; and (3) minimum-presence mid-winter. The variation in seasonal presence was concurrent with coarse migratory patterns of humpback whales, and yearly variations in presence presumably reflect a shift in the influx and efflux of whales between years. The extended presence of humpbacks in this area suggests that Massachusetts Bay is an important, year-round habitat for the Gulf of Maine sub-population, and may warrant revision of management and regulatory practices to reflect this presence.

scholarly journals Pruning Effects on the Cold Hardiness of `Haggerston Gray' Leyland Cypress and `Natchez' Crape Myrtle

HortScience ◽  
1991 ◽  
Vol 26 (11) ◽  
pp. 1381-1383 ◽  
Author(s):  
C.L. Hayns ◽  
O.M. Lindstrom ◽  
M.A. Dirr
Keyword(s):  
Cold Hardiness ◽  
Late Summer ◽  
Early Spring ◽  
Late Winter ◽  
Early Winter ◽  
Maximum Difference

The effects of late summer, fall, and winter pruning on the cold hardiness of × Cupressocyparis leylandii (A.B. Jacks. and Dallim.) Dallim. and A.B. Jacks. `Hag gerston Gray' (Leyland cypress) and Lagerstroemia L. `Natchez' (crape myrtle) were determined. Pruning in late summer through early winter significantly reduced the cold hardiness of both taxa. The maximum difference in cold hardiness between pruned trees and controls for × Cupressocyparis leylandii `Haggerston Gray' in October, December, January, and February was 3, 3, 2, and 6C, respectively. The maximum difference in cold hardiness between pruned plants and controls for Lagerstroemia `Natchez' in December, January, and February was 3, 4, and 2C, respectively. Early spring pruning of Leyland cypress and late winter or early spring pruning of crape myrtle are suggested from these data.

Biology of Rock Crab (Cancer irroratus) in Northumberland Strait

1972 ◽  
Vol 29 (2) ◽  
pp. 161-166 ◽  
Author(s):  
D. J. Scarratt ◽  
Robert Lowe
Keyword(s):  
Sex Ratio ◽  
Surface Waters ◽  
Sea Urchins ◽  
Carapace Width ◽  
Late Summer ◽  
Fishing Gear ◽  
Size At Maturity ◽  
Cancer Irroratus ◽  
Rock Crab ◽  
Commercial Size

Divers hand-collected 342 rock crabs (Cancer irroratus) ranging from 4.2 mm carapace width to 97 mm (females) and 127 mm (males). The sex ratio (1.37:1) was biased in favour of males. Of 2929 crabs taken in commercial lobster fishing gear, 92% were above the minimum commercial size of 89 mm, and of these 99.1% were male. Smallest size at maturity was 60 mm for females and 69 mm for males. Breeding occurred in late summer and fall. Larvae were present in surface waters from June to September. Prey of crabs > 25 mm consisted principally of polychaetes, mussels, starfish, and sea urchins. Crabs less than about 65 mm inhabit rocky areas; larger crabs move out onto sand and mud. The fishable population is probably not in significant competition with lobsters for food or space.

Reproductive dynamics of the tiger prawn Penaeus esculentus, and a comparison with P. semisulcatus, in the north-western Gulf of Carpentaria, Australia

1987 ◽  
Vol 38 (1) ◽  
pp. 91 ◽  
Author(s):  
PJ Crocos
Keyword(s):  
Egg Production ◽  
Reproductive Output ◽  
Size Range ◽  
Early Spring ◽  
Minimum Size ◽  
Late Winter ◽  
Limited Area ◽  
The North ◽  
Tiger Prawn ◽  
North Western

The reproductive cycle of female P. esculentus was investigated in the Groote Eylandt region of the Gulf of Carpentaria from August 1983 to March 1985. The minimum size at maturity for P. esculentus was 25 mm carapace length (CL), and 50% of the population were mature at 32 mm CL. The proportion of females which had mated increased sharply above 28 mm CL to a maximum of 80% inseminated in the size range 32-50 mm CL. An index of population egg production, calculated from female abundance, the proportion of females spawning and fecundity with size, was used as an indicator of reproductive output. Egg production tended to be spread throughout the year, but with eggs being produced most consistently in late winter and early spring. Spawning occurred in a limited area within the study area. A comparison of P. esculentus and P. semisulcatus showed that P. esculentus matures at a smaller size (50% at 32 mm CL) than P. semisulcatus (50% at 39 mm CL), fecundity is lower, spawning is nearer inshore and egg production is less strongly seasonal.

The biology of Gammarus (Crustacea, Amphipoda) in the northwestern Atlantic. II. Gammarus setosus Dementieva

1970 ◽  
Vol 48 (4) ◽  
pp. 659-671 ◽  
Author(s):  
V. J. Steele ◽  
D. H. Steele
Keyword(s):  
Sexual Maturity ◽  
Early Spring ◽  
Late Winter ◽  
Bay Of Fundy ◽  
Size At Maturity ◽  
Northwest Atlantic ◽  
High Fecundity ◽  
Large Size ◽  
Long Life ◽  
Resting Period

Gammarus setosus is a circumpolar species found as far south as the Bay of Fundy region in the northwest Atlantic. Under laboratory conditions (3 °C) sexual maturity is reached in the 13th molt, at 14 mm in the males and at 12 mm in the females. In the field 50%, maturity is attained at 13.5 mm in the females. Mature females annually produce a single autumn brood, which is released in late winter or early spring. They then enter an obligatory resting period. In the laboratory at 12 °C they can have more than one brood annually. Fecundity increases with the size of the Female. The large size at maturity, continued growth, and long life with resulting high fecundity partially compensate for the production of but one brood per year.

scholarly journals Influence of Northern Hemispheric Winter Warming on the Pacific Storm Track

2021 ◽  
Author(s):  
Hyung-Ju Park ◽  
Kwang-Yul Kim
Keyword(s):  
Heat Flux ◽  
Global Warming ◽  
Energy Conversion ◽  
Storm Track ◽  
The Arctic ◽  
Late Winter ◽  
Turbulent Heat ◽  
Early Winter ◽  
Eddy Heat Flux ◽  
Northern Hemispheric

AbstractEffect of global warming on the sub-seasonal variability of the Northern Hemispheric winter (NDJFM) Pacific storm-track (PST) activity has been investigated. Previous studies showed that the winter-averaged PST has shifted northward and intensified, which was explained in terms of energy exchange with the mean field. Effect of global warming exhibits spatio-temporal heterogeneity with predominance over the Arctic region and in the winter season. Therefore, seasonal averaging may hide important features on sub-seasonal scales. In this study, distinct sub-seasonal response in storm track activities to winter Northern Hemispheric warming is analyzed applying cyclostationary empirical orthogonal function analysis to ERA5 data. The key findings are as follows. Change in the PST is not uniform throughout the winter; the PST shifts northward in early winter (NDJ) and intensifies in late winter (FM). In early winter, the combined effect of weakened baroclinic process to the south of the climatological PST and weakened barotropic damping to the north is responsible for the northward shift. In late winter, both processes contribute to the amplification of the PST. Further, change in baroclinic energy conversion is quantitatively dominated by eddy heat flux, whereas axial tilting of eddies is primarily responsible for change in barotropic energy conversion. A close relationship between anomalous eddy heat flux and anomalous boundary heating, which is largely determined by surface turbulent heat flux, is also demonstrated.

Seasonal activity and estivation of lumbricid earthworms in the midlands of Tasmania

Soil Research ◽  
1994 ◽  
Vol 32 (6) ◽  
pp. 1355 ◽  
Author(s):  
RB Garnsey
Keyword(s):  
Soil Moisture ◽  
Adult Development ◽  
Survival Rates ◽  
Soil Surface ◽  
Early Spring ◽  
Lumbricus Rubellus ◽  
Late Winter ◽  
Cocoon Production ◽  
Density And Biomass ◽  
Earthworm Activity

Earthworms have the ability to alleviate many soil degradational problems in Australia. An attempt to optimize this resource requires fundamental understanding of earthworm ecology. This study reports the seasonal changes in earthworm populations in the Midlands of Tasmania (<600 mm rainfall p.a.), and examines, for the first time in Australia, the behaviour and survival rates of aestivating earthworms. Earthworms were sampled from 14 permanent pastures in the Midlands from May 1992 to February 1994. Earthworm activity was significantly correlated with soil moisture; maximum earthworm activity in the surface soil was evident during the wetter months of winter and early spring, followed by aestivation in the surface and subsoils during the drier summer months. The two most abundant earthworm species found in the Midlands were Aporrectodea caliginosa (maximum of 174.8 m-2 or 55.06 g m-2) and A. trapezoides (86 m-2 or 52.03 g m-2), with low numbers of Octolasion cyaneum, Lumbricus rubellus and A. rosea. The phenology of A. caliginosa relating to rainfall contrasted with that of A. trapezoides in this study. A caliginosa was particularly dependent upon rainfall in the Midlands: population density, cocoon production and adult development of A. caliginosa were reduced as rainfall reduced from 600 to 425 mm p.a. In contrast, the density and biomass of A. trapezoides were unaffected by rainfall over the same range: cocoon production and adult development continued regardless of rainfall. The depth of earthworm aestivation during the summers of 1992-94 was similar in each year. Most individuals were in aestivation at a depth of 150-200 mm, regardless of species, soil moisture or texture. Smaller aestivating individuals were located nearer the soil surface, as was shown by an increase in mean mass of aestivating individuals with depth. There was a high mortality associated with summer aestivation of up to 60% for juvenile, and 63% for adult earthworms in 1993 in the Midlands. Cocoons did not survive during the summers of 1992 or 1994, but were recovered in 1993, possibly due to the influence of rainfall during late winter and early spring.

Sign in / Sign up

Export Citation Format

Share Document