Pelagic Amphipoda of the Belle Isle Strait Region

1951 ◽  
Vol 8b (3) ◽  
pp. 134-163 ◽  
Author(s):  
E. L. Bousfield
Keyword(s):  
Light Intensity ◽  
Breeding Season ◽  
Cold Water ◽  
Ocean Currents ◽  
Southern Limit ◽  
Index Species ◽  
Labrador Current ◽  
Themisto Libellula

The distribution of certain pelagic Amphipoda taken in the Belle Isle strait region during the summer of 1923 is correlated with ocean currents, light intensity and size of individuals. Hyperoche medusarum, Themisto libellula and Pseudalibrotus glacialis are index species of the cold Labrador current in the area. Hyperia galba and H. medusarum are presumably also cold water indicators. Themisto abyssorum in sizeable numbers, and Calliopius laeviusculus are related to waters of the gulf of St. Lawrence. Themisto libellula, T. compressa form compressa and T. compressa form bispinosa are more numerous, while T. abyssorum is less numerous at the surface during daylight than during darkness. Part of the breeding season of T. compressa and T. abyssorum occurs in the area during August and September, when the young of both species are much more numerous than the adults, particularly at the surface. A new southern limit of distribution for P. glacialis is established. The known distribution of the tropical genus Phronima is extended into the gulf of St. Lawrence.

The Marine Environment

2020 ◽  
Author(s):  
Professor John Swarbrooke
Keyword(s):  
Marine Environment ◽  
Cold Water ◽  
Vital Role ◽  
Ocean Currents ◽  
The Sun ◽  
Weather Patterns ◽  
The World ◽  
Sheer Size ◽  
Almost All ◽  
Life On Earth

The fact that open ocean covers two-thirds of the surface of our planet dramati- cally illustrates the importance of the marine environment to life on Earth. But the importance of the oceans goes far beyond their sheer size for it is the oceans that largely determine our climate for the weather around the world is heavily influenced by what happens in our seas. ‘Weather patterns are primarily controlled by ocean currents which are influenced by surface winds, temperature, salinity, the Earth’s rotation and ocean tides....Ocean currents bring warm water and rain from the equator to the poles and cold water from the poles towards the equator’ (www.greentumble.com, 2016). Every schoolchild knows that the sun evaporates water from the sea which then become clouds that then produces almost all of the rain and snow which falls on every land mass in the world. The oceans also absorb heat from the sun and from human activities; this heat is then carried to the land in those places where the prevailing winds blow from the sea to the land. At the same time, the oceans play a vital role in the carbon cycle by absorbing carbon dioxide that is in the air.

The Flatback Turtle, Chelonia depressa, in Queensland: Reproductive Periodicity, Philopatry and Recruitment

1984 ◽  
Vol 11 (3) ◽  
pp. 579 ◽  
Author(s):  
CJ Limpus ◽  
A Fleay ◽  
V Baker
Keyword(s):  
Breeding Season ◽  
Sea Turtles ◽  
Recruitment Rate ◽  
Southern Limit ◽  
Total Fecundity ◽  
Eastern Australia ◽  
Reproductive Life ◽  
Breeding Seasons ◽  
Remigration Interval ◽  
High Degree

The Bundaberg coast is the southern limit for reproduction by Chelonia depressa in eastern Australia. Here the species lays 2.84 � 0.78 (mean � SD) clutches per breeding season with a renesting interval of 15.99 � 1.89 days. When successful nesting does not occur on a nesting crawl the female returns after 1.17 � 1.07 d for another attempt. The mean remigration interval is 2.65 � 0.92 years and the average female is estimated to have a reproductive life of between 2.05 and 2.55 breeding seasons. The estimated annual recruitment rate of neonate nesting females into this colony is 27.2 � 10.8% of the population. The females return repetitively with a high degree of accuracy to the same small nesting beach within a single breeding season and in successive breeding seasons. The reproductive strategy of C. depressa compared with that of other sea turtles appears to involve an increase in hatchling size, to reduce predation, achieved by laying relatively large eggs. However, only a few small clutches are laid in a breeding season, so that seasonal fecundity for the species is low relative to that in other sea turtles such as C. mydas. Because its reproductive life is longer, C. depressa has a total fecundity only slightly less than that of C. mydas.

scholarly journals Constant timing of medusa release in bivalve-inhabiting hydrozoans of the genus Eugymnanthea (Hydrozoa: Leptomedusae: Eirenidae)

2008 ◽  
Vol 88 (8) ◽  
pp. 1607-1609 ◽  
Author(s):  
Shin Kubota
Keyword(s):  
Light Intensity ◽  
Water Temperature ◽  
Breeding Season ◽  
Laboratory Experiments ◽  
Mytilus Galloprovincialis ◽  
Congeneric Species ◽  
Natural Conditions ◽  
Night Time

At the end of the breeding season in autumn, under natural conditions, mature medusae of Eugymnanthea japonica are released from its host Mytilus galloprovincialis at night-time. In laboratory experiments, mature medusae of the congeneric species E. inquilina are also released at night-time in autumn. At that time of the year, sunset is earlier and the water temperature is lower than in summer, when, under natural conditions, medusa release of E. japonica takes place at sunset instead. The release thus takes place at the same hours of the day in summer as well as in autumn. The circadial timing of medusa release of E. japonica is likely constant throughout the whole period in the breeding season and not correlated with the decrease of light intensity at sunset.

scholarly journals Cold Water Flow and Upper-Ocean Currents in the Bismarck Sea from December 2001 to January 2002

2011 ◽  
Vol 41 (4) ◽  
pp. 827-834 ◽  
Author(s):  
Takuya Hasegawa ◽  
Kentaro Ando ◽  
Hideharu Sasaki
Keyword(s):  
Papua New Guinea ◽  
Coastal Upwelling ◽  
Cold Water ◽  
Coastal Region ◽  
South Pacific ◽  
Ocean Currents ◽  
Upper Ocean ◽  
Thermal Change ◽  
Budget Analysis ◽  
Thermal Changes

Abstract The authors investigated the upper-ocean currents in the Bismarck Sea and related oceanic thermal changes in the western equatorial South Pacific for December 2001–January 2002; during this period, coastal upwelling occurred along the Papua New Guinea (PNG) coast. Southeastward and northwestward coastal currents toward the central PNG coast appeared along northern and southern PNG, respectively. In addition, westward currents extended toward central PNG in the southern part of the Bismarck Sea. A northeastward outflow toward the equator from the PNG coastal area, which is compensated for by such flows, was also found. Volume budget analysis in the upper ocean showed that, during the analysis period, the northeastward outflow ranged from +1.0 to +2.0 Sv (1 Sv ≡ 106 m3 s−1). This northeastward outflow brought relatively cool coastal water, which is related to PNG coastal upwelling, to the western equatorial South Pacific near PNG during this period. In addition, the upper-ocean temperature in this region showed a cooling tendency in line with a negative heat transport from the PNG coastal region. The present results indicate that northeastward transport of the cold water is related to the complicated upper-ocean currents in the Bismarck Sea and may have strongly affected the upper-ocean thermal change in the western equatorial Pacific near PNG for December 2001–January 2002.

On the breeding season of Lipophrys pholis (Pisces: Blenniidae) at Arrábida, Portugal

1990 ◽  
Vol 70 (4) ◽  
pp. 913-916 ◽  
Author(s):  
Vitor C. Almada ◽  
Eduardo N. Barata ◽  
Emanuel J. Gonçalves ◽  
Ruif De Oliveira
Keyword(s):  
Breeding Season ◽  
Black Males ◽  
Southern Limit ◽  
The North ◽  
Direct Observations ◽  
North Eastern ◽  
The North Sea ◽  
Vertical Walls ◽  
Considerable Work ◽  
A Site

Direct observations of egg masses on the shore indicates that Lipophrys pholis is a winter and spring spawner in Portuguese waters. The results are compared with those published for the British Isles.Lipophrys pholis, Linnaeus, 1758, is a very common intertidal fish in the north-eastern Atlantic and in the North Sea. Considerable work has been published concerning its breeding season in British waters (Lebour, 1927; Qasim, 1957; Shackley & King, 1977). The breeding season of the species at the southern limit of its range is almost unknown, and Zander (1986) mentions the period from April to August for the whole species. Based on dates of first appearance of larvae in plankton collected in the Bay of Biscay, Villegas (1981) concluded that breeding should have begun as early as the end of December.In this report we present data on the spawning season of this blenny based on direct observation of the presence of eggs and/or parental guarding males on the shore.Data were collected at a site located at Arrábida (38°28′N, 8°59′W), near Senibal, 50 km south of Lisbon, Portugal. In the course of behavioural observations on the breeding males of L. pholis, the area was visited at various intervals during the period 1986 to 1989. The nests were located intertidally in holes in vertical walls. On each visit, the presence of eggs and/or black males inside the nests was registered. Each nest was mapped for inspection in subsequent visits. The results are summarized in Figure 1.It is clear that in our study area breeding begins as early as December, and has virtually ended in June.

Interannual variation of the southern limit in the Yellow Sea Bottom Cold Water and its causes

2014 ◽  
Vol 139 ◽  
pp. 119-127 ◽  
Author(s):  
Hee-Won Yang ◽  
Yang-Ki Cho ◽  
Gwang-Ho Seo ◽  
Sung Hyup You ◽  
Jang-Won Seo
Keyword(s):  
Yellow Sea ◽  
Interannual Variation ◽  
Cold Water ◽  
The Yellow Sea ◽  
Southern Limit ◽  
Sea Bottom ◽  
Bottom Cold Water

Growth, reproductive cycle and penis shedding of Littorina littorea in the Ria de Aveiro (north-west Portugal)

2007 ◽  
Vol 87 (2) ◽  
pp. 547-550 ◽  
Author(s):  
C.M. Barroso ◽  
C. Gonçalves ◽  
M.H. Moreira
Keyword(s):  
Breeding Season ◽  
Reproductive Cycle ◽  
Species Distribution ◽  
Shell Height ◽  
Littorina Littorea ◽  
Von Bertalanffy ◽  
Southern Limit ◽  
Ria De Aveiro ◽  
North West ◽  
Distribution In Europe

The growth and the reproductive cycle of Littorina littorea were investigated in the Ria de Aveiro, Portugal, a country cited as the southern limit of the species distribution in Europe. Littorina littorea growth is well represented by the von Bertalanffy equation SH=24.6[1-e-0.69(t-0.70)] where SH is the shell height (distance from shell apex to the basis of the aperture measured in mm) and t is the number of winters: after periwinkles have reached a mean SH of 4.6 mm in their first winter they grow progressively to about 14.6 mm, 19.6 mm, 22.1 mm and 23.4 mm in the following four years and they attain the asymptotic mean maximum SH of 24.6 mm at the tenth year if they survive. Ripening of the gonads occurred from October to May but was more intense from December to February, whereas spawning extended from January to May in females and November to May in males. There was a seasonal shedding of the male penis at the end of the breeding season (summer) accompanying regression of the testis.

Distribution of the plankton in relation to the Antarctic Convergence

1964 ◽  
Vol 281 (1384) ◽  
pp. 21-38 ◽  
Keyword(s):  
Cold Water ◽  
Sharp Change ◽  
Southern Limit ◽  
The North ◽  
Biological Phenomena ◽  
Antarctic Convergence ◽  
Distribution Limits ◽  
Large Water ◽  
The Antarctic ◽  
North And South

The Antarctic Convergence is often adopted now as the northern boundary of the ‘Antarctic’ region as a whole, for at least in relation to oceanographic and biological phenomena it is a much more realistic line than the Antarctic circle. It is a well-defined boundary between large water masses, and such a dividing line can be very significant in the distribution of life in the sea, especially of the plankton. About 500 to 700 miles north of it lies the Subtropical Convergence, recognized by a very sharp change of temperature at the surface, and this is clearly the southern limit of many species in the zooplankton and the northern limit of a smaller number in the less varied fauna to the south. It is the boundary between the warm and cold-water epipelagic faunas, and it probably constitutes a real barrier to the dispersal of many species. There is less difference in sea temperatures on the north and south sides of the Antarctic Convergence, but since it is the interface between surface waters of separate origin and distinct properties, and the point at which the layers or currents are changing their depth, we should expect it also to mark certain distribution limits.

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