scholarly journals The harbour porpoise (Phocoena phocoena) in the North Atlantic: Variability in habitat use, trophic ecology and contaminant exposure

2003 ◽  
Vol 5 ◽  
pp. 223 ◽  
Author(s):  
Arne Bjørge
Keyword(s):  
Habitat Use ◽  
North Atlantic ◽  
Coastal Waters ◽  
Trophic Ecology ◽  
Point Sources ◽  
Phocoena Phocoena ◽  
Cetacean Species ◽  
Contaminant Exposure ◽  
The North ◽  
Management Plans

Harbour porpoises inhabit coastal waters, in habitats that are characterized by high diversity and complexity in terms of their bathymetry, substrate, fish communities and point sources of contaminants. The complexity in these habitats influences both the habitat use and feeding ecology of porpoises. Congregations of porpoises feeding primarily on one species are observed in some areas and seasons, while wide movements and diets composed of several species are observed in other areas. Due to these observations, this paper suggests that caution is needed when extrapolatingknowledge from one area to another with regard to porpoise habitat use, exposure to contaminants, and interactions with fisheries. Management plans should be site specific and based on local knowledge incorporating porpoise population structure, habitat use, and multiple environmental factors in order to ensure appropriate conservation of this abundant but still vulnerable small cetacean species.

Trophic ecology and foraging areas of cetaceans sampled in the coastal waters of south-eastern Brazil assessed through skin δ13C and δ15N

2021 ◽  
pp. 1-10
Author(s):  
Victor Uber Paschoalini ◽  
Genyffer Cibele Troina ◽  
Laura Busin Campos ◽  
Marcos César de Oliveira Santos
Keyword(s):  
Habitat Use ◽  
Coastal Waters ◽  
Trophic Ecology ◽  
Trophic Position ◽  
Trophic Levels ◽  
Eastern Coast ◽  
Cetacean Species ◽  
Δ13c And Δ15n ◽  
South Eastern ◽  
Eastern Brazil

Abstract We investigated the habitat use and feeding ecology of 10 cetacean species encountered along the south-eastern coast of Brazil (24–26°S) using carbon (δ13C) and nitrogen (δ15N) stable isotopes. Hierarchical cluster analysis distinguished two main groups based on their isotopic patterns. One group included migratory baleen whales (Megaptera novaeangliae and Eubalaena australis) with the lowest δ13C and δ15N values, reflecting baseline isotopic values of their Subantarctic feeding grounds and consumption of lower trophic level prey. Resident species and those occasionally occurring in Brazilian coastal waters highly differed from the migratory whales in their isotopic values. In this group, Tursiops truncatus had the highest δ13C and δ15N values, indicating coastal habits and relatively higher trophic position. Similar δ13C values were observed in Sotalia guianensis, Pontoporia blainvillei, Orcinus orca and Steno bredanensis. However, the former two species had lower δ15N values than the latter two, indicating different trophic positions. The relatively lower δ13C values observed in Stenella frontalis suggest greater influence of pelagic prey in their diet. Furthermore, the lower δ13C values observed in Delphinus delphis and Balaenoptera edeni were associated with upwelling events that occur along the region, affecting the isotopic values of their main prey. Juvenile M. novaeangliae had higher δ13C and δ15N than the adults, which may indicate feeding in areas with different isoscapes and consumption of pelagic schooling fish with relatively higher trophic levels than krill. This study provides preliminary information that are useful to understand the habitat use and coexistence of cetacean species occurring in south-eastern Brazil.

First record of Norwegian killer whales attacking and feeding on a harbour porpoise

2015 ◽  
Vol 8 ◽  
Author(s):  
A. Mel Cosentino
Keyword(s):  
North Atlantic ◽  
Marine Mammals ◽  
First Record ◽  
Harbour Porpoise ◽  
Sperm Whales ◽  
Killer Whales ◽  
Strait Of Gibraltar ◽  
Cetacean Species ◽  
The North ◽  
Northern Bottlenose Whales

Orcinus orcais a cosmopolitan species and the most widely distributed marine mammal. Its diet includes over 140 species of fish, cephalopods, sea birds and marine mammals. However, many populations are specialised on certain specific prey items. Three genetically distinct populations have been described in the North Atlantic. Population A (that includes the Icelandic and Norwegian sub-populations) is believed to be piscivorous, as is population C, which includes fish-eating killer whales from the Strait of Gibraltar. In contrast, population B feeds on both fish and marine mammals. Norwegian killer whales follow the Norwegian spring spawning herring stock. The only description in the literature of Norwegian killer whales feeding on another cetacean species is a predation event on northern bottlenose whales in 1968. Daily land-based surveys targeting sperm whales were conducted from the Andenes lighthouse using BigEyes®binoculars (25×, 80 mm). The location of animals at sea was approximated through the use of an internal reticule system and a graduated wheel. On 24 June 2012 at 3:12 am, an opportunistic sighting of 11 killer whales was made off Andenes harbour. The whales hunted and fed on a harbour porpoise. Despite these species having overlapping distributions in Norwegian waters, this is the first predatory event reported in the literature.

Temperature, Salinity and Plankton in the Eastern North Atlantic and Coastal Waters of Britain, 1957.: I. The Characterisation and Distribution of Surface Waters

1963 ◽  
Vol 20 (3) ◽  
pp. 789-826 ◽  
Author(s):  
B. McK. Bary
Keyword(s):  
North Sea ◽  
North Atlantic ◽  
Coastal Waters ◽  
Water Bodies ◽  
English Channel ◽  
Oceanic Water ◽  
Climatic Fluctuations ◽  
The North ◽  
The North Sea ◽  
Eastern North Atlantic

Monthly temperature-salinity diagrams for 1957 have demonstrated that three surface oceanic "water bodies" were consistently present in the eastern North Atlantic; two are regarded as modified North Atlantic Central water which give rise to the third by mixing. As well in the oceanic areas, large and small, high or low salinity patches of water were common. Effects of seasonal climatic fluctuations differed in the several oceanic water bodies. In coastal waters, differences in properties and in seasonal and annual cycles of the properties distinguish the waters from the North Sea, English Channel and the western entrance to the Channel.The geographic distributions of the oceanic waters are consistent with "northern" and "southern" water bodies mixing to form a "transitional" water. Within this distribution there are short-term changes in boundaries and long-term (seasonal) changes in size of the water bodies.Water in the western approaches to the English Channel appeared to be influenced chiefly by the mixed, oceanic transitional water; oceanic influences in the North Sea appear to have been from northern and transitional waters.

scholarly journals Artificial light in baited pots substantially increases the catch of cod (Gadus morhua) by attracting active bait, krill (Thysanoessa inermis)

2018 ◽  
Vol 75 (6) ◽  
pp. 2257-2264 ◽  
Author(s):  
Odd-Børre Humborstad ◽  
Anne Christine Utne-Palm ◽  
Michael Breen ◽  
Svein Løkkeborg
Keyword(s):  
Light Source ◽  
North Atlantic ◽  
Coastal Waters ◽  
Gadus Morhua ◽  
Catch Rate ◽  
Light Sources ◽  
The North ◽  
Important Prey ◽  
Large Numbers ◽  
Per Se

Abstract The use of pots in the north Atlantic finfish fisheries is negligible because this fishing method typically has a low capture efficiency. Large numbers of individuals encounter baited pots, but the proportions of fish that enter the pot and become caught are low. Krill, which constitutes an important prey for cod (Gadus morhua), is attracted by light. The catching efficiency of baited cod pots with three light sources with different colours and intensities (white: 9744 mW m−2, white: 23 mW m−2, green: 8 mW m−2) were tested in coastal waters in northern Norway. Pots with the light source of highest intensity gave a 17 times higher catch rate of cod than that of control pots (with bait only). The light source of medium intensity gave about a five times higher catch rate, whereas the weakest light did not influence the catch. Cod caught in pots with light had more krill and arrowworms in their stomach and were observed feeding on these preys inside the pot. We concluded that light sources of increasing intensity attract more krill, and that cod were attracted into the pot by the dense swarms of prey and not the light per se.

Reproduction in the common porpoise (Phocoena phocoena) of the North Atlantic

2009 ◽  
Vol 161 (2) ◽  
pp. 471-486 ◽  
Author(s):  
H. Dean Fisher ◽  
Richard J. Harrison
Keyword(s):  
North Atlantic ◽  
Phocoena Phocoena ◽  
The North ◽  
The Common ◽  
The North Atlantic

scholarly journals Early Winter Habitat Use by Mountain Caribou in the North Cariboo and Columbia Mountains, British Columbia

Rangifer ◽  
1996 ◽  
Vol 16 (4) ◽  
pp. 133 ◽  
Author(s):  
E. Terry ◽  
B. McLellan ◽  
G. Watts ◽  
J. Flaa
Keyword(s):  
British Columbia ◽  
Habitat Use ◽  
Regional Differences ◽  
Rangifer Tarandus ◽  
Winter Habitat ◽  
Use Patterns ◽  
The North ◽  
Columbia Mountains ◽  
Management Plans ◽  
Spruce Stands

Winter habitat use was compared between two mountain caribou (Rangifer tarandus caribou) populations in British Columbia. Regional differences were apparent during November and December. Radio-collared caribou inhabiting the gentle plateaus of the northern Cariboo Mountains, near Prince George, B.C. primarily used mid-elevation balsam-spruce stands on moderate slopes (<30%). In contrast, radio-collared caribou in the North Columbia Mountains, near Revelstoke, B.C. used low elevation hemlock-cedar stands and relatively steeper slopes (>30%). To adequately address habitat requirements of caribou, forest management plans should incorporate varying regional and seasonal habitat use patterns. Hypotheses on observed differences in habitat use are discussed.

scholarly journals Summer Abundance of Harbour Porpoises (Phocoena phocoena) in the Coastal Waters of Iceland and the Faroe Islands

2020 ◽  
Vol 11 ◽  
Author(s):  
Anita Gilles ◽  
Thorvaldur Gunnlaugsson ◽  
Bjarni Mikkelsen ◽  
Daniel G. Pike ◽  
Gísli A. Víkingsson
Keyword(s):  
Coastal Waters ◽  
Harbour Porpoise ◽  
Line Transect ◽  
Faroe Islands ◽  
Phocoena Phocoena ◽  
The North ◽  
Counting Procedure ◽  
Abundance Estimates ◽  
By Catch ◽  
The Impact

This study presents the first fully corrected abundance estimates for the harbour porpoise (Phocoena phocoena) for Iceland and the Faroe Islands. In both regions reliable estimates are needed to assess the impact of by-catch and other threats to harbour porpoises. Aerial surveys with harbour porpoise as a secondary and main target species were conducted in the summers of 2007 and 2010 in Icelandic and in Faroese coastal waters respectively. In Iceland, the cue counting procedure was used (which also produces the data required for line transect analysis), while in the Faroese, standard line transect sampling was applied, following the SCANS-II (Small Cetacean Abundance in the North Sea) survey protocol. In both surveys, identical aircraft surveyed at an altitude of 600 ft and a speed of 90–100 kn. Only data collected during Beaufort Sea States (BSS) lower than 3 and during good or moderate porpoise sighting conditions were used for abundance estimates. Abundance estimates were corrected using stratified estimates of esw (incorporating g(0)) values derived during the SCANS-II survey in 2005 as principal observers took part in this survey as well. In Iceland, realised effort in good or moderate harbour porpoise sighting conditions totalled 8,289 km in 13 survey strata, where 77 sightings (109 individuals) were made by the experienced harbour porpoise observer only. In Faroese waters, only part of the area inside the 300 m depth curve could be surveyed and 1,564 km were surveyed in good or moderate porpoise sighting conditions, yielding 39 sightings (49 individuals). The total abundance estimates were 43,179 porpoises (CV=0.45; 95% CI: 31,755–161,899) for Icelandic coastal waters and 5,175 porpoises (CV=0.44; 95% CI: 3,457–17,637) for Faroese waters.

scholarly journals The effects of salinity on the developing eggs and larvae of the herring

1960 ◽  
Vol 39 (3) ◽  
pp. 591-603 ◽  
Author(s):  
F. G. T. Holliday ◽  
J. H. S. Blaxter
Keyword(s):  
North Atlantic ◽  
Coastal Waters ◽  
North Atlantic Ocean ◽  
Clupea Harengus ◽  
Tamar Estuary ◽  
The North ◽  
The Pacific ◽  
Series Of Experiments ◽  
Eggs And Larvae ◽  
Kiel Canal

The herring(Clupea harengus L.) deposits its eggs in the coastal waters around the North Atlantic Ocean, North Sea, and Baltic Sea. The salinity on the spawning grounds may vary from about 35%0 to 5%0. For instance, Brandhorst (1959) reports that successful spawning tookplace in the Kiel Canal in salinities down to 5%0, and Ford (1929) records that ripe herring have been found in the Tamar estuary. In a series of experiments Ford found that the eggs of herring could be successfully fertilized and incubated even in a salinity of 4·8%0. McMynn & Hoar (1953) investigated the effect of salinity on the development of the Pacific herringC. pallasii and found it had a wide tolerance, the lower level being somewhere between o and 6‰

scholarly journals Stratigraphy of volcanic rock successions of the North Atlantic rifted margin: the offshore record of the Faroe–Shetland and Rockall basins

2021 ◽  
pp. 1-28
Author(s):  
David W. JOLLEY ◽  
John M. MILLETT ◽  
Nick SCHOFIELD ◽  
Lena BROADLEY ◽  
Malcolm J. HOLE
Keyword(s):  
North Atlantic ◽  
Volcanic Activity ◽  
High Volume ◽  
Flood Basalt ◽  
Point Sources ◽  
Accommodation Space ◽  
The North ◽  
Mid Ocean Ridge ◽  
Ocean Ridge ◽  
Rifted Margin

ABSTRACT The integration of biostratigraphical, wireline log, geophysical and available geochronological ages has identified two principal periods of volcanism in the Faroe–Shetland and Rockall basins. The first is pre-breakup, upper Danian to lower Thanetian: in the Rockall and Faroe–Shetland basins, isolated volcanic activity from 62 Ma to 58.7 Ma is identified in areas closely linked to the SSW–NNE structural fabric of the continental margin. Volcanic activity was concentrated at basin flank fissures and localised point sources. This rift-flank volcanism led to widespread volcanic ash deposition, localised lava flow fields and the formation of igneous centres. Some of the Hebridean and onshore central complexes (e.g., Rum) were uplifted and rapidly eroded during the later pre-breakup period, while additional accommodation space was developed in the adjacent offshore basins. Onset and termination of pre-breakup volcanism is correlated to intra-plate stress regimes in Europe, following the cessation of convergence of Africa and Europe in the Danian. The second is syn-breakup, upper Thanetian to Ypresian, initiated at ca.57 Ma in the Rockall and Faroe–Shetland basins. Initial high-volume extrusive igneous successions were focussed to the W in the Faroe–Shetland Basin. In the centre and E of the Faroe–Shetland and Rockall basins, separate eruption loci developed along pre-existing lineaments either as fissure or point-sourced lava fields. Short-term cessation of eruption at ~55.8 Ma was followed by resumption of flood basalt eruptions and a shift in focus to the NW. Fluctuations in the syn-breakup eruption tempo are reflected in the formation and subsequent rejuvenation of prominent unconformities, only previously recognised as a single erosive event. The W and northward shift of eruption focus, and the eruption of mid ocean ridge basalt-type lavas in the syn-breakup period reflect the onset of lithospheric thinning in the nascent North Atlantic Rift prior to flooding of the rift and eruption of the widespread lower Ypresian Balder Formation tephras.

scholarly journals Estimates of Cetacean Abundance in the North Atlantic of Relevance to NAMMCO

2020 ◽  
Vol 11 ◽  
Author(s):  
Geneviève Desportes
Keyword(s):  
North Atlantic ◽  
Cetacean Species ◽  
The North ◽  
Abundance Estimates ◽  
The North Atlantic

The best available abundance estimates for cetacean species in areas of relevance to the work of NAMMCO since 1986 are presented and the references to the original sources is provided.

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