Life history of a wide-ranging deepwater lantern shark in the north-east Atlantic,Etmopterus spinax(Chondrichthyes: Etmopteridae), with implications for conservation

Examination of the reproductive biology of the abyssal seastar Dytaster grandis taken at different times of the year in the NE Atlantic suggests seasonal reproduction that is related to the seasonal pulse of phytodetritus to the deep-sea floor. Although this seastar is an omnivore, the availability of this labile organic material may fuel vitellogenesis during the summer and autumn months. The egg size suggests planktotrophic larval development. Spawning occurs in the early part of each year to allow the zygote to develop into a feeding larva to coincide with the downward flux of phytodetritus. Thus the flux of detritus may constitute an environmental forcing pressure at least at two points in the life history of D. grandis.

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Nautical Chart Standardization

Journal of Navigation ◽

10.1017/s0373463300039825 ◽

1983 ◽

Vol 36 (3) ◽

pp. 468-479

Author(s):

D. W. Newson

Keyword(s):

Large Scale ◽

East Atlantic ◽

Nautical Chart ◽

North East ◽

The North ◽

History Of ◽

The North Sea ◽

Successful Establishment ◽

Atlantic Area ◽

Two Bodies

This paper deals with the work of the International Hydrographic Organisation (IHO) during the last ten years towards the standardization of nautical charts. The work began with the devising of a regional scheme of medium- and large-scale sheets of the north-east Atlantic area, to be co-produced by member nations as contributions to an International (INT) set of charts. It subsequently became clear that, as well as the scheme, a detailed set of specifications would be necessary to secure uniformity of choice of symbols and abbreviations throughout the International series, and also in the various national chart series of which it would form a part.The history of nautical chart standardization has recently been traced by Ritchie – gradual at first after the beginning of the International Hydrographic Bureau in 1921, and later speeding up when the International Hydrographic Conference of 1967 established a study which led to two series of INT charts on very small scales. After this the process gathered further speed with the successful establishment of the two bodies with whose work this paper is primarily concerned: the North Sea International Chart Commission (NSICC) in 1972 and the Chart Specifications (later Standardization) Committee (CSC) in 1977. The ten-nation NSICC, in drawing up the network of INT sheet-lines for its area, established the principles on which such schemes would be extended worldwide and also did extensive groundwork for the Chart Specifications of the IHO. These were completed for worldwide application by the seventeen-nation CSC.

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Life-history biology of Peniagone azorica and P. diaphana (Echinodermata: Holothurioidea) from the north-east Atlantic Ocean

Marine Biology ◽

10.1007/bf00392879 ◽

1985 ◽

Vol 89 (1) ◽

pp. 71-81 ◽

Cited By ~ 32

Author(s):

P. A. Tyler ◽

J. D. Gage ◽

D. S. M. Billett

Keyword(s):

Life History ◽

Atlantic Ocean ◽

East Atlantic ◽

North East ◽

The North

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The ecology and reproductive biology of Cherbonniera utriculus and Molpadia blakei from the N.E. Atlantic

Journal of the Marine Biological Association of the United Kingdom ◽

10.1017/s0025315400026680 ◽

1987 ◽

Vol 67 (2) ◽

pp. 385-397 ◽

Cited By ~ 8

Author(s):

P. A. Tyler ◽

D. S. M. Billett ◽

J. D. Gage

Keyword(s):

New Genus ◽

Great Variability ◽

The Arctic ◽

New Genus And Species ◽

East Atlantic ◽

Norwegian Sea ◽

The Past ◽

North East ◽

The North ◽

History Of

The Molpadiida is an order of sea cucumbers identified by their stout body, the posterior region narrowing to simulate a tail and the absence of tubefeet. Typically they inhabit muddy environments from shallow water to abyssal depths. In the past the great variability in the taxonomic characters of this order has led to the formation of many genera and species (Heding, 1931, 1935), but more recently it has become apparent that many diagnostic characters change markedly during the life history of these holothurians and as a result fewer species are now recognised (Deichmann, 1940; Pawson, 1977). In a revision of the Atlantic molpadiids Deichmann (1940) recorded just three species from the north-east Atlantic (Molpadia blakei, M. musculus and Hedingia albicans) with a further three species from the Arctic Ocean and Norwegian Sea (M. arctica, M. borealis and Eupyrgus scaber). To these Sibuet (1974) added the new genus and species Cherbonniera utriculus found in the Bay of Biscay.

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Spatio-Temporal Variability of Harbor Porpoise Life History Parameters in the North-East Atlantic

Frontiers in Marine Science ◽

10.3389/fmars.2020.502352 ◽

2020 ◽

Vol 7 ◽

Author(s):

Sinéad Murphy ◽

Marie A. C. Petitguyot ◽

Paul D. Jepson ◽

Rob Deaville ◽

Christina Lockyer ◽

...

Keyword(s):

Life History ◽

Average Length ◽

Mortality Data ◽

Limiting Factor ◽

Harbor Porpoise ◽

East Atlantic ◽

Extrinsic Factors ◽

Early Maturation ◽

North East ◽

The North

Harbor porpoises exhibit early maturation, relatively short gestation/lactation periods and a faster rate of reproduction as compared to other cetacean species. Intrinsic and extrinsic factors can influence both population vital rates and population structure, which ultimately cause changes in dynamics within and between populations. Here, we undertook a retrospective analysis of mortality data collected over a 24-year period for assessing life history traits of the North-east Atlantic harbor porpoise population. We use time-period specific models for key life history relationships that considered cause of death of individuals (as a proxy for health status), sex and management unit (MU). Sexual variation in asymptotic length, asymptotic age, average length at 50% maturity (L50) and average age at 50% maturity (A50) were observed, with females attaining a larger asymptotic length, larger L50, and delaying attainment of both sexual and physical maturity, compared to males. While females are constrained in their minimum body size due to giving birth to proportionally larger offspring, males exhibited more plasticity in size at sexual maturity, enabling re-allocation of available energy resources toward reproduction. Data were then used to compare biological parameters among two porpoise MUs in United Kingdom waters, both of which in the current study exhibited reduced reproductive rates compared to other geographic regions. In both MUs, females significantly increased their A50 and males significantly declined in their L50. An increase in the age at asymptotic length was also observed in both sexes, along with a significant decline in the Gompertz growth rate parameter that was more apparent in the female data. While availability of suitable prey resources may be a limiting factor, a combination of other factors cannot be ruled out. Porpoises in the Celtic and Irish Seas MU were significantly larger in their maximum length, asymptotic length and L50 compared to porpoises in the North Sea MU throughout the study period, suggesting limited gene flow between these two MUs. These results justify the maintenance of these harbor porpoise MUs or assessment units, as two separate units, within the range of the North-east Atlantic population, and for indicator assessments under the EU’s Marine Strategy Framework Directive.

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THE LIFE-HISTORY OF NANNOTHEMIS BELLA, UHLER

The Canadian Entomologist ◽

10.4039/ent33252-9 ◽

1901 ◽

Vol 33 (9) ◽

pp. 252-255 ◽

Cited By ~ 2

Author(s):

R. Weith ◽

J. G. Needham

Keyword(s):

Life History ◽

Boundary Line ◽

Field Observations ◽

East Atlantic ◽

Atlantic Seaboard ◽

North East ◽

History Of ◽

The City

1. Field Observations on the Habits of the Species, by R. Weith.Nannothemis bella, Uhl., is one of the smallest of dragon-flies. Of its life-history we have had no knowledge up to the present time. Until the publicetion of Williamson's Catalogue of the Dragon-flies of Indiana, last year, it was recorded only from our north-east Atlantic seaboard. I have frequently met with it in Elkhart and St. Joe Counties, the two northermost counties in Indiana; but, what has been most perplexing to me, only in a few very restricted areas, these areas not exceeding 50 yards in length by 25 yards in width from margin of lake. The only places I have met with it are at Simonton Lake, a distance of four and one-half miles from the City of Elkhart, Indiana, and Indiana and Baldwin Lakes, thirteen miles north-east of Elkhart, on the boundary line that divides Indiana from Michigan. In the latter place, on a smaller area than at Simonton Lake, the imago is very numerous. Frequent endeavors to find the species at other places where similar conditions prevail proved unsuccessful.

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Ras al Khaimah: further archaeological discoveries

Antiquity ◽

10.1017/s0003598x00150070 ◽

1976 ◽

Vol 50 (200) ◽

pp. 216-222

Author(s):

Beatrice De Cardi

Keyword(s):

United Arab Emirates ◽

The State ◽

Focused Attention ◽

North East ◽

The North ◽

History Of ◽

The City

Ras a1 Khaimah is the most northerly of the seven states comprising the United Arab Emirates and its Ruler, H. H. Sheikh Saqr bin Mohammad al-Qasimi, is keenly interested in the history of the state and its people. Survey carried out there jointly with Dr D. B. Doe in 1968 had focused attention on the site of JuIfar which lies just north of the present town of Ras a1 Khaimah (de Cardi, 1971, 230-2). Julfar was in existence in Abbasid times and its importance as an entrep6t during the sixteenth and seventeenth centuries-the Portuguese Period-is reflected by the quantity and variety of imported wares to be found among the ruins of the city. Most of the sites discovered during the survey dated from that period but a group of cairns near Ghalilah and some long gabled graves in the Shimal area to the north-east of the date-groves behind Ras a1 Khaimah (map, FIG. I) clearly represented a more distant past.

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