scholarly journals The Occurrence and Breeding of Sagitta Elegans Verrill and Sagitta Setosa J. Müller in Parts of the Irish Sea

Author(s):  
E. Lowe Pierce

An investigation has been made of the species of Sagitta present in parts of the Irish Sea, their relative occurrence, and the annual number of reproductive cycles of each species. Three stages of maturity as described by Russell (1932a) have been used. To determine the maturity the Sagitta were transferred to a solution of 75% alcohol and stained with borax carmine.S. elegans Verrill and S. setosa J. Müller were collected in Liverpool Bay and in Port Erin harbour, Isle of Man. The former species was predominant at Port Erin. The coasts of Liverpool Bay have been added to the permanent range of S. setosa.At Port Erin there appears to be but one chief spawning period for S. elegans which extends generally from January through May. Following May the young forms appear in numbers and gradually mature through December to repeat the annual cycle.There appear to be two main breeding seasons for S. setosa in the outer Mersey Channels. The first and most noticeable begins in April and extends into June. There is evidence for a second breeding period in August.Both species were found in the samples taken from Morecambe Bay and Anglesey. The stage of maturity of these agreed with the Sagitta caught at the same time at Port Erin and Liverpool.The total monthly catches of Sagitta from Port Erin and the outer Mersey Channels have been recorded.

2007 ◽  
Vol 64 (4) ◽  
pp. 587-601 ◽  
Author(s):  
J Kennedy ◽  
P R Witthames ◽  
R DM Nash

The fecundity of European plaice (Pleuronectes platessa) in the Irish Sea between 2000 and 2004 was estimated during the spawning season for fish in the three main spawning areas (Liverpool Bay, the Cumbrian coast, and the western Irish Sea) and one small spawning group on the west coast of the Isle of Man. Fecundity was also estimated during September of 2003 and 2004. The aim of this was to assess the variability in fecundity between areas and years in the Irish Sea and also to identify when differences in fecundity become apparent in the maturation cycle. There were variations in fecundity on both the temporal and spatial scales. The greatest variation in fecundity between years occurred in the western Irish Sea, whereas there was no variation between years in the southeastern Irish Sea (Liverpool Bay). There was no difference in fecundity between areas or years during September. The maximum fecundity in plaice is determined by the total weight of the fish at the end of follicle recruitment in the ovary, and differences in the fecundity of each population are the result of different levels of down-regulation in the period between the end of follicle proliferation and spawning.


Author(s):  
P. G. W. Jones ◽  
A. R. Folkard

INTRODUCTIONStudies on the physical hydrography of the Irish Sea, based mainly on temperature and salinity observations, have been made by Bowden (1955) and Lee (1960). The current systems in various parts of the Irish Sea have been investigated by Bowden & Sharaf El Din (1966), Harvey (1968), Ramster & Hill (1969) and Hill & Ramster (1971). Various smaller-scale physical observations made by other workers have been listed by the above authors.There are not as many references in the literature to the distribution of nutrient salts in the Irish Sea. Jones & Haq (1963) measured phosphate in Liverpool Bay as part of an investigation into the distribution of the alga Phaeocystis. Slinn & Offlow (1968) have made regular routine measurements of phosphate, nitrate and silicate over a number of years off Port Erin, Isle of Man. Ewins & Spencer (1967) measured phosphate, organic phosphorus, nitrate and silicate in the Menai Straits, and Liss (1969) surveyed the distribution of silicate in the western Irish Sea.During recent years the Fisheries Laboratory at Lowestoft has investigated the distribution and ecology of plankton and larval plaice in the Irish Sea, and a supporting programme of both physical and chemical hydrographic observations has been made in the area. Ramster & Hill (1969) and Hill & Ramster (1971) have summarized the results of the Lowestoft current measurements. The present paper describes an investigation into the distribution of temperature, salinity, phosphate, nitrate and silicate. The occurrence of Phaeocystis is also reported as an extension of the earlier work by Jones & Haq (1963).


2000 ◽  
Vol 39 (2) ◽  
pp. 217-240 ◽  
Author(s):  
John Belchem

As imperial pride flourished in the racial discourse of late Victorian British politics, ethnic revival and Celtic nationalism also gained purchase and resonance. These complex and seemingly competing issues of identity extended beyond the “four nations” of the United Kingdom to the Isle of Man, a crown dependency constitutionally outside the United Kingdom but at the very center of the British Isles. In this “land of home rule,” adrift in the Irish Sea, the juxtaposition of Britishness and Celticism was particularly acute, compounded by the proud persistence of Norse traditions. Manx independence within the Atlantic archipelago was symbolized by the annual Tynwald Day ceremony, a Viking “Thing” or general meeting, at which the year's new legislation was promulgated in both English and Manx Gaelic. In the late Victorian period, as Anglo-Manx business syndicates invested heavily in the “visiting industry,” transforming the island into “one large playground for the operatives of Lancashire and Yorkshire,” gentlemanly antiquarians constructed (and/or invented) the necessary traditions to safeguard Manx cultural distinctiveness and its devolved political status. Through the assertion of Celticism, a project that tended to downgrade Norse contributions to the island's past, the little Manx nation girded itself against cultural anglicization, yet remained unquestionably loyal to the British empire.Slightly other than English, the Manx have displayed what Sir Frank Kermode has described as “mild alienation” and “qualified foreignness,” characteristics that need to be considered in the wider debate about British identity.


Author(s):  
Vicki Cummings

The transition from the Mesolithic to the Neolithic in Britain and Ireland remains one of the most debated and contested transitions of prehistory. Much more complex than a simple transition from hunting and gathering to farming, the Mesolithic–Neolithic transition in Britain has been discussed not only as an economic and technological transformation, but also as an ideological one. In western Britain in particular, with its wealth of Neolithic monuments, considerable emphasis has been placed on the role of monumentality in the transition process. Over the past decade the author‧s research has concentrated on the early Neolithic monumental traditions of western Britain, a deliberate focus on areas outside the more ‘luminous’ centres of Wessex, the Cotswold–Severn region, and Orkney. This chapter discusses the transition in western Britain, with an emphasis on the monuments of this region. In particular, it discusses the areas around the Irish Sea – west Wales, the Isle of Man, south-west and western Scotland – as well as referring to the sequence on the other side of the Irish Sea, specifically eastern Ireland.


Author(s):  
David M. Wilson

This chapter examines the influences in the early sculpture in the Isle of Man, particularly the crosses that were previously described as Celtic. It suggests that the inscriptions in the Manx sculpture epigraphically and linguistically relate the island to the lands round the Irish Sea, while their typology and style history provide rough chronological yardsticks. The findings reveal that most pre-Viking memorial stones can be found in cemeteries on the sites of keeills.


Author(s):  
J. B. Sykes ◽  
A. D. Boney

Until recently there has been very little information on the quantities of phytoplankton nutrients in the Irish Sea. Slinn (1958–1966) has reported the weekly variations in the nutrient concentrations at a station off Port Erin, Isle of Man, and studies on the nutrient conditions in the Menai Straits have been carried out by Jones (unpublished) and Ewins & Spencer (1967). Liss (1969) has reported on the results of winter surveys of reactive silicate near the Irish coast, and from three stations near the Welsh coast (Anglesey, the Lleyn Peninsula and Fishguard). The present paper describes studies carried out in the inshore waters near Aberystwyth in Cardigan Bay during 1967 and 1968. This investigation formed part of a study of the seasonal occurrence of the phytoplankton and the growth conditions in this shallow, inshore region.


Author(s):  
W. A. Herdman

The Liverpool Marine Biology Committee was formed in March, 1885, for the purpose of investigating thoroughly the Fauna and Flora of Liverpool Bay and the neighbouring parts of the Irish Sea. The aim of the Committee is not merely to draw up an accurate list of the species found in this locality, but also to observe and record the relative numbers, the size, the colours, and the condition generally of the specimens, the exact localities in which they are found, the other species of animals and plants associated with them, and their mutual relations as food, enemies, or competitors. In this way it is hoped that a mass of observations will be accumulated which may be of use in determining the geographical distribution of various forms, the nature of the conditions which influence species, and the relations existing between the different plants and animals. It was felt at the outset that this work was exactly that department of biological investigation which could be best carried out by an organised body of workers who would subdivide the area to be investigated, and the groups of animals and plants to be worked up between them, and would carry on systematic observations year after year, sending in periodic reports upon their work. The value, in fact the absolute necessity, of this organisation, division of labour, and systematic arrangement, for the successful accomplishment of the objects in view, has been felt all along by the members of the Committee and those naturalists who have worked with them; and the results attained so far have, I think, fully justified their belief in the benefit to be derived from scientific organisation.


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