scholarly journals The genetic composition of feeding aggregations of the Atlantic mackerel (Scomber scombrus) in the central north Atlantic: a microsatellite loci approach

2020 ◽  
Vol 77 (2) ◽  
pp. 604-612
Author(s):  
Davið Gíslason ◽  
Sarah J Helyar ◽  
Guðmundur J Óskarsson ◽  
Guðbjörg Ólafsdóttir ◽  
Aril Slotte ◽  
...  
Keyword(s):  
North Atlantic ◽  
Microsatellite Loci ◽  
Migration Patterns ◽  
Fish Stocks ◽  
North West ◽  
Atlantic Mackerel ◽  
Scomber Scombrus ◽  
The North ◽  
Specific Contribution ◽  
Impacts Of Climate Change

Abstract The impacts of climate change on marine ecosystems can be seen in the changing distribution, migration, and abundance of species in the oceans. For some species this changing environment may be beneficial and can support population expansions. In the northeast Atlantic (NEA), the Atlantic mackerel (Scomber scombrus) is undergoing an increase in stock size accompanied by changing summer migration patterns, which have resulted in an expansion further north and north west than previously recorded. This study uses microsatellite loci to confirm the differentiation among NEA and northwest Atlantic (NWA) mackerel spawning populations and to assess the level of structuring within these populations. In addition, to enable population-specific exploitation rates to be factored into fisheries management, we identified the origin of individuals composing the expanding feeding aggregations in the central north Atlantic (Greenland, Iceland, Faroes), with all aggregations tested originating from spawning populations in the NEA. This study showed that microsatellite loci were useful to assess the contribution of NEA and NWA populations to mixed feeding aggregations across the north Atlantic for large pelagic fish stocks but were not powerful enough to evaluate the specific contribution of known stocks within NEA and NWA.

scholarly journals Temperature constraints shaped the migration routes of mackerel (Scomber scombrus) in the Black Sea

2017 ◽  
Vol 58 (2) ◽  
pp. 337-344 ◽  
Author(s):  
Daniel Pauly ◽  
Çetin Keskin
Keyword(s):  
Black Sea ◽  
North Atlantic ◽  
The Black Sea ◽  
Seasonal Temperature ◽  
Migration Routes ◽  
Atlantic Mackerel ◽  
Scomber Scombrus ◽  
The North ◽  
And Migration ◽  
Induced Changes

Conventional narratives explain fish migrations in term of requirements (food, mates, habitats, etc.), with adequate temperatures being optional. Here, using the example of a (commercially extinct) stock of Black Sea mackerel (Scomber scombrus), we suggest that seasonal migrations are driven by seasonal temperature cycles. Therein, temperature acts as a constraint determining where the fish can be at any given time, and not a one of several factors which they would consider when choosing between alternative migration routes. Generalizing, we suggest that temperature should generally be an explicit part of hypotheses about the migratory behaviours of marine fishes. For illustration of what may occur when this is not the case, it is suggested that the non-consideration of temperature in a model of North Atlantic mackerel migration may have led, among the researchers concerned, to a sense of complacency with respect to the climate change-induced changes in the phenology of this fish in the North Atlantic, whose distribution and migration are misleadingly seen as “stochastic”.

Mapping Spatio-Temporal Variability in NAO Rainfall Signatures

2021 ◽  
Author(s):  
Harry West ◽  
Nevil Quinn ◽  
Michael Horswell
Keyword(s):  
Spatial Pattern ◽  
North Atlantic ◽  
Temporal Variability ◽  
Reliable Estimate ◽  
Jet Stream ◽  
Temporal Consistency ◽  
North West ◽  
The North ◽  
Cold Spots ◽  
Spatio Temporal

<p>The North Atlantic Oscillation (NAO) is often cited as the primary atmospheric-oceanic circulation or teleconnection influencing regional climate in Great Britain. As our ability to predict the NAO several months in advance improves, it is important that we also continue to develop our spatial and temporal understanding of the rainfall signatures which the circulation produces.</p><p>We present a novel application of spatial statistics to explore variability in monthly NAO rainfall signatures using a 5km gridded monthly Standardised Precipitation Index (SPI) dataset. We first use the Getis-Ord Gi* statistic to map spatially significant hot and cold spots (clusters of high/wet and low/dry SPI values) in average monthly rainfall signatures under NAO Positive and Negative conditions over the period 1900-2015. We then look across the record and explore the temporal variability in these signatures, in other words how often a location is in a significant spatial hot/cold spot (high/low SPI) at a monthly scale under NAO Positive/Negative conditions.</p><p>The two phases of the NAO are typically more distinctive in the winter months, with stronger and more variable NAO Index values. The average monthly SPI analysis reveals a north-west/south-east ‘spatial divide’ in rainfall response. NAO Positive phases result in a southerly North Atlantic Jet Stream bringing warm and wet conditions from the tropics, increasing rainfall particularly in the north-western regions. However, under NAO Negative phases which result in a northerly Jet Stream, much drier conditions in the north-west prevail. Meanwhile in the south-eastern regions under both NAO phases a weaker and opposite wet/dry signal is observed. This north-west/south-east ‘spatial divide’ is marked by the location of spatially extensive hot/cold spots. The Getis-Ord Gi* result identifies that the spatial pattern we detect in average winter rainfall is statistically significant. Looking across the record, this NW/SE opposing response appears to have a relatively high degree of spatio-temporal consistency. This suggests that there is a high probability that NAO Positive and Negative phases will result in this NW/SE statistically significant spatial pattern.</p><p>Even though the phases of the NAO in the summer months are less distinctive they still produce rainfall responses which are evident in the monthly average SPI. However, the spatiality in wet/dry conditions is more homogenous across the country. In other words the ‘spatial divide’ observed in winter is diluted in summer. As a result, the occurrence of significant hot/cold spots is more variable in space and time.</p><p>Our analysis demonstrates a novel application of the Getis-Ord Gi* statistic which allows for spatially significant patterns in the monthly SPI data to be mapped for each NAO phase. In winter months particularly, this analysis reveals statistically significant opposing rainfall responses, which appear to have long-term spatio-temporal consistency. This is important because as winter NAO forecasting skill improves, the findings of our research enable a more spatially reliable estimate of the likely impacts of NAO-influenced rainfall distribution.</p>

Modelling Atlantic mackerel spawning habitat suitability and its future distribution in the north‐west Atlantic

2019 ◽  
Vol 29 (1) ◽  
pp. 84-99
Author(s):  
Baye Mbaye ◽  
Thomas Doniol‐Valcroze ◽  
Pablo Brosset ◽  
Martin Castonguay ◽  
Elisabeth Van Beveren ◽  
...  
Keyword(s):  
Habitat Suitability ◽  
Spawning Habitat ◽  
North West ◽  
Atlantic Mackerel ◽  
The North

scholarly journals Deforestation and Human Agency in the North Atlantic Region: Archaeological and Palaeoenvironmental Evidence from the Western Isles of Scotland

2018 ◽  
Vol 84 ◽  
pp. 145-184 ◽  
Author(s):  
Rosie R. Bishop ◽  
Mike J. Church ◽  
Ian T. Lawson ◽  
Katherine H. Roucoux ◽  
Charlotte O’Brien ◽  
...  
Keyword(s):  
Bronze Age ◽  
North Atlantic ◽  
North Atlantic Region ◽  
Late Neolithic ◽  
Atlantic Region ◽  
North West ◽  
Farming Communities ◽  
The North ◽  
New Synthesis ◽  
Main Period

This paper considers the timing and mechanisms of deforestation in the Western Isles of Scotland, focusing in particular on the landscape around the Calanais stone circles, one of the best preserved late Neolithic/early Bronze Age monumental landscapes in north-west Europe. We present new archaeological and palaeoenvironmental evidence from a soil and peat sequence at the site of Aird Calanais, which spans the main period of use of the Calanais circles. We then draw on a new synthesis of archaeobotanical and palynological evidence from across the Western Isles and a review of comparable data from the wider North Atlantic zone, before assessing the role of early farming communities in clearing the wooded landscapes of the region. Pollen and radiocarbon dating at the site of Aird Calanais reveal that a layer of birch branches, dating to the late Neolithic (2912–2881 calbc), was contemporaneous with a decline in woodland at the site, as well as with the major phase of Neolithic activity at the Calanais stone circle complex. However, our synthesis of the pollen and plant macrofossil evidence from across the Western Isles suggests that the picture across these islands was altogether more complex: woodlands declined both before, as well as during, the Neolithic and deciduous woodlands remained sufficiently abundant for Neolithic fuel procurement. Finally, we consider the implications of the results for understanding the interactions between first farmers and woodlands in the wider North Atlantic region.

Seasonal Migration Patterns of Postlarval and Juvenile Banana Prawns, Penaeus merguiensis de Man, in the Major Rivers of the Gulf of Carpentaria, Australia

1979 ◽  
Vol 30 (2) ◽  
pp. 143 ◽  
Author(s):  
DJ Staples
Keyword(s):  
Seasonal Pattern ◽  
Temporal Distribution ◽  
Major Change ◽  
Seasonal Migration ◽  
Geographical Differences ◽  
Monsoon Period ◽  
Migration Patterns ◽  
North West ◽  
The North ◽  
Two Generations

Samples of juvenile P. merguiensis taken from 20 major rivers around the Gulf of Carpentaria from 1970 to 1973 showed that the Gulf could be divided into four major areas, each characterized by its own seasonal pattern of postlarval immigration and emigration of juveniles. The main nursery areas for the Gulf, however, are the rivers along the east and south-east coasts (Cape Keerweer to Mornington Island) and the majority of prawns migrate from these rivers during the north-west monsoon period (November to February); the main recruitment into the commercial fishery, there- fore, occurs during a relatively confined period each year. Additional sampling in 1976-77 showed that although there have been recent changes in the temporal distribution of adult prawns as a result of increased fishing pressure, no major change in the temporal pattern of postlarval immigration has resulted. An hypothesis is presented in which the observed geographical differences in the seasonal migration patterns are explained with reference to a basic pattern involving two generations of P. merguiensis each year.

Meristic Analyses of Atlantic Mackerel, Scomber scombrus, from the North American Coastal Populations

1969 ◽  
Vol 26 (9) ◽  
pp. 2537-2540 ◽  
Author(s):  
K. T. MacKay ◽  
E. T. Garside
Keyword(s):  
Atlantic Ocean ◽  
Growth Rates ◽  
Biochemical Evidence ◽  
Atlantic Mackerel ◽  
Scomber Scombrus ◽  
Dorsal Fin ◽  
The North ◽  
Breeding Populations ◽  
Fin Rays ◽  
Genetic Continuity

Mean counts of vertebrae, of anal and soft dorsal fin rays, and of peduncular finlets were identical in samples of Atlantic mackerel, Scomber scombrus, from the northern and southern breeding populations in the northwest Atlantic Ocean. This information, together with growth rates and biochemical evidence from the literature, suggests that although the populations occupy separate spawning regions there is sufficient exchange of individuals at other seasons to maintain considerable genetic continuity.

Northern Range Extension of the Atlantic Mackerel, Scomber scombrus, to Black Island, Labrador

1970 ◽  
Vol 27 (3) ◽  
pp. 610-613 ◽  
Author(s):  
L. S. Parsons
Keyword(s):  
North Atlantic ◽  
Coastal Waters ◽  
Range Extension ◽  
Range Limit ◽  
Atlantic Mackerel ◽  
Scomber Scombrus ◽  
Northern Range Limit

During August 1969, 785 specimens of Scomber scombrus were captured in southern Labrador coastal waters, extending the known range in the western North Atlantic to Black Island, Labrador, more than 50 miles north of Triangle Harbour, the previously authenticated northern range limit.

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