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

2015 ◽  
Vol 8 ◽  
Author(s):  
A. Mel Cosentino

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.


2012 ◽  
Vol 81 (3) ◽  
pp. 1133-1137 ◽  
Author(s):  
R. P. Vieira ◽  
B. Christiansen ◽  
S. Christiansen ◽  
J. M. S. Gonçalves


2020 ◽  
Vol 287 (1938) ◽  
pp. 20202318
Author(s):  
James P. Rule ◽  
Justin W. Adams ◽  
Felix G. Marx ◽  
Alistair R. Evans ◽  
Alan J. D. Tennyson ◽  
...  

Living true seals (phocids) are the most widely dispersed semi-aquatic marine mammals, and comprise geographically separate northern (phocine) and southern (monachine) groups. Both are thought to have evolved in the North Atlantic, with only two monachine lineages—elephant seals and lobodontins—subsequently crossing the equator. The third and most basal monachine tribe, the monk seals, have hitherto been interpreted as exclusively northern and (sub)tropical throughout their entire history. Here, we describe a new species of extinct monk seal from the Pliocene of New Zealand, the first of its kind from the Southern Hemisphere, based on one of the best-preserved and richest samples of seal fossils worldwide. This unanticipated discovery reveals that all three monachine tribes once coexisted south of the equator, and forces a profound revision of their evolutionary history: rather than primarily diversifying in the North Atlantic, monachines largely evolved in the Southern Hemisphere, and from this southern cradle later reinvaded the north. Our results suggest that true seals crossed the equator over eight times in their history. Overall, they more than double the age of the north–south dichotomy characterizing living true seals and confirms a surprisingly recent major change in southern phocid diversity.



Author(s):  
Andrés Arias ◽  
Hannelore Paxton

AbstractRhamphobrachium (Rhamphobrachium) agassizii is reported from the Cantabrian Sea, Spain, from depths of 925–1207 m. This is its first record off the Iberian Peninsula and in European waters, representing its northernmost distribution in the North Atlantic Ocean to date. Previous reports of R. (R.) agassizii from the eastern and western North Atlantic demonstrate its apparent amphi-Atlantic distribution, which appears consistent with the distribution of the main Atlantic currents. It is a typical deep-water species with its deepest record at 2165 m from the Azores archipelago. The specimens were collected singly at two stations, attesting to the rarity of the species in contrast to its congener R. (Spinigerium) brevibrachiatum which was the most dominant polychaete species in a previous study.



2019 ◽  
pp. 1-21
Author(s):  
Xénia Keighley ◽  
Morten Tange Olsen ◽  
Peter Jordan

AbstractThe hunting of marine mammals as a source of subsistence, trade, and commercial revenue has formed an important part of human cultures across the North Atlantic. One important prey species has been the Atlantic walrus (Odobenus rosmarus rosmarus), sought after for meat, skin, blubber, ivory, and bone. Unfortunately, biological studies of current walrus populations and studies across the humanities and social sciences into past use and hunting of walruses, have been poorly integrated. Disciplinary boundaries have left a gap in understanding the reciprocal effects of human-walrus interactions. Emerging interdisciplinary methods offer new opportunities to write the historical ecology of Atlantic walruses. The integration of methods such as ancient DNA, isotopes, past population modelling, zooarchaeological assemblages, and ethnographic interviews can now be used to answer previously intractable questions. For example, how has walrus hunting shaped and been influenced by changes in human settlement and trade, what have been the cumulative impacts on walrus populations, the extent of anthropogenic selective pressures or the effect of changing hunting regimes on particular populations of walruses? New, collaborative research approaches applied to the wealth of Arctic archaeological faunal remains already housed in museum collections offer a unique chance to explore the past dynamics of human-animal interactions.



Author(s):  
Noureddine Abid ◽  
Amin Laglaoui ◽  
Abdelhay Arakrak ◽  
Mohammed Bakkali

During the period from April to September for the years 2014–2016, 998 swordfishes caught by the Moroccan artisanal longline fishery in the Strait of Gibraltar were sampled to study the reproduction of this species in this mixing area between the Mediterranean Sea and the North Atlantic. The results showed that the sex ratio is slightly in favour of males for sizes smaller than 130 cm LJFL (Lower jaw-fork length), whereas females are more numerous in sizes larger than 140 cm LJFL. Fifty per cent of females were estimated to be mature at 170 cm LJFL, while for males, the size at first maturity was estimated to be 95 cm LJFL. The swordfish spawn from June to September, probably in the Mediterranean Sea. The findings of this study suggest that the reproductive characteristics of swordfish caught in the Strait of Gibraltar are similar to those of the Mediterranean swordfish, and a high mixing rate between the Mediterranean and the North Atlantic stocks occurs in the study area.



1999 ◽  
Vol 144 (21) ◽  
pp. 588-592 ◽  
Author(s):  
M. Tryland ◽  
L. Kleivane ◽  
A. Alfredsson ◽  
M. Kjeld ◽  
A. Arnason ◽  
...  


1989 ◽  
Vol 67 (10) ◽  
pp. 2592-2595 ◽  
Author(s):  
Tracy A. Stevens ◽  
Deborah A. Duffield ◽  
Edward D. Asper ◽  
K. Gilbey Hewlett ◽  
Al Bolz ◽  
...  

A preliminary assessment of mitochondrial DNA restriction patterns in the killer whale (Orcinus orca) was conducted using 10 captive North Atlantic killer whales from the southeastern coast of Iceland, a captive-born offspring of one of these whales, and 9 North Pacific killer whales. No restriction pattern variation was seen among these whales, using the enzymes BamH I, Bgl II, Hinf I, Kpn I, or Pvu II. Restriction pattern variation was found using the enzyme Hae III. This restriction endonuclease distinguished the North Atlantic killer whales (type 1) from the North Pacific killer whales. The North Pacific killer whales were further differentiated into two groups: those originating from the "resident" communities of the Vancouver Island region (type 2), and those from the "transient" community of Vancouver Island, as well as those stranded along the Oregon coast (type 3). The observed Hae III restriction pattern differences suggest that mitochondrial DNA analysis will be a valuable technique for investigating regional and local distributions of maternal lineages among killer whale pods, especially in the North Pacific.



Author(s):  
A. Sabatés ◽  
M. Demestre ◽  
P. Sanchez

The study of the morphological and meristic characters of larval and adult sandeels (Gymnammodytes spp.) collected off the Catalan coast (NW Mediterranean) has revealed the co-occurrence of G. cicerelus and G. semisquamatus in the Mediterranean. The geo-graphical distribution of G. semisquamatus had hitherto been thought to be limited to the European Atlantic coasts. The comparative analysis of specimens of G. semisquamatus from the Mediterranean and from the North Atlantic has demonstrated a marked latitudinal cline in the meristic counts. An exhaustive overview is presented of the bibliography referring to the Ammodytidae family in the Mediterranean, and the validity of the numerous references is discussed. Finally, it has been shown that the accepted description of G. cicerelus included the two species: G. cicerelus and G. semisquamatus. In the present paper an up-to-date diagnosis of both species is presented.



2003 ◽  
Vol 5 ◽  
pp. 41 ◽  
Author(s):  
Christina Lockyer

Wide-ranging methods that have been used to determine population structure, including distribution, life history, biology, ecological factors such as diet and contaminant loads, morphology and genetics, are reviewed. The importance of determining population sub-structure of harbour porpoise throughout the North Atlantic, especially in regions affected by incidental take in fisheries, is discussed in relation to management measures. Some practical proposals are made for integrating diverse information about populations, using the phylogeographic approach, for thepurpose of evaluating the need to manage putative subpopulations separately. Examples focusingon the North and Baltic seas areas are used in this discussion, with some reference to other areas. It is concluded that the existing IWC proposal for 13 populations in the North Atlantic is generally supported, but with some refinement and modification; in particular, allowing sub-divisions in the area through the North Sea to the Baltic.



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