Rencular morphology and renal vascular system of the harbour porpoise Phocoena phocoena (L.)

1979 ◽  
Vol 57 (4) ◽  
pp. 868-875 ◽  
Author(s):  
N. A. Hedges ◽  
D. E. Gaskin ◽  
G. J. D. Smith
Keyword(s):  
Body Weight ◽  
North Atlantic ◽  
Vascular System ◽  
Vascular Supply ◽  
Harbour Porpoise ◽  
Phocoena Phocoena ◽  
Parasympathetic Nerves ◽  
Injection Techniques ◽  
Renal Vascular

The kidneys of 35 harbour porpoises, Phocoena phocoena (L.), from the western North Atlantic were studied. Kidneys are large (0.84% of body weight) and multirenculate (approximately 300 renculi per kidney). Renculi have well developed medullary papillae (71–80% of rencular thickness) which correlates well with an ability to produce concentrated urine. Zonation of the vascular system within the medulla is also present, another characteristic of mammals producing concentrated urine.The intrarencular vascular supply is typically mammalian and similar to other cetaceans. As a result of excellent injection techniques, we found greater complexity and variability in the vascular system in our specimens than has been previously reported.Vascular control is discussed in relation to diving bradycardia. Parasympathetic nerves may stimulate vasodilation to quickly restore rencular circulation at the end of a dive.

Comparative volumes and vascular microanatomy of the intrahepatic venous system of the harbour porpoise, Phocoena phocoena (L.)

1978 ◽  
Vol 56 (11) ◽  
pp. 2292-2298 ◽  
Author(s):  
J. W. Hilton ◽  
D. E. Gaskin
Keyword(s):  
Vena Cava ◽  
Liver Weight ◽  
Harbour Porpoise ◽  
Venous System ◽  
Portal System ◽  
Hepatic Veins ◽  
Phocoena Phocoena ◽  
Diaphragmatic Muscle ◽  
Injection Techniques ◽  
Portal Veins

The intrahepatic venous systems of the harbour porpoise, Phocoena phocoena, were studied using single and double injection techniques. Large band-like formations of elastin fibres were found in the dilated terminal portions of the major hepatic veins and the adjacent section of the caudal vena cava but not in the equivalent major branches of the thicker walled portal veins. The hepatic venous system increases in volume disproportionately with increase in body length and liver weight; the portal system does not. No distal sphincter formations were found in the major hepatic veins, nor were sphincters or valves present in the portal system. The vena cava, however, is surrounded by a loop of diaphragmatic muscle or 'caval sling,' which may cause significant occlusion of the vena cava following inspiration. The distensible terminal portions of the major hepatic veins and the adjacent portion of the caudal vena cava could then function as a temporary blood reservoir or 'intrahepatic sinus.' While this would be a relatively inefficient mechanism for preventing ventricular engorgement, it might be sufficient for the needs of P. phocoena, which is a relatively poor diver.

A comparison of age determination techniques for the harbour porpoise, Phocoena phocoena L.

1989 ◽  
Vol 67 (7) ◽  
pp. 1832-1836 ◽  
Author(s):  
Peter Watts ◽  
David E. Gaskin
Keyword(s):  
North Atlantic ◽  
Age Determination ◽  
Harbour Porpoise ◽  
Phocoena Phocoena ◽  
Growth Layer ◽  
Single Cross Section ◽  
Living Bone ◽  
Layer Groups ◽  
Annual Deposition ◽  
Age Estimates

The maximum life-span of the harbour porpoise has been estimated at 13 years (based upon dentinal growth layer groups in the teeth) and at 21 years (based upon growth layers in the periosteal bone of the mandible). We used both techniques to estimate the ages of 120 harbour porpoises from the western North Atlantic, in an attempt to determine the relative reliability of each technique. Dentinal layering was the better predictor of body length. Mandibular layering was highly variable even within a single cross section in most specimens, as a result of both common bifurcation of the layers and destruction of the inner layers by growth and remodelling of the living bone. Furthermore, mandibular layers appear to be deposited at a rate of 2 layers/year, double the deposition rate of dentinal growth layer groups. Age estimates which assume annual deposition of mandibular layers therefore overestimate true age.

scholarly journals Harbour porpoise (Phocoena phocoena) in the North Atlantic: Abundance, removals, and sustainability of removals

2003 ◽  
Vol 5 ◽  
pp. 271 ◽  
Author(s):  
G B Stenson
Keyword(s):  
North Atlantic ◽  
Harbour Porpoise ◽  
Phocoena Phocoena ◽  
The North ◽  
Number Of Factors ◽  
The Status ◽  
Substantial Progress ◽  
Potential Population ◽  
The North Atlantic ◽  
The Impact

The status of harbour porpoise (Phocoena phocoena) populations in the North Atlantic has raised numerous concerns. Although a number of factors that may be adversely affecting harbour porpoise populations have been identified, focus has been on the impact of removals, primarily due to incidental catches in fishing gear. As a result, considerable efforts have been made to determine the levels and/or impact of bycatch in a number of areas. Unfortunately, many areas remain little studied. Currently, harbour porpoise are listed as threatened or vulnerable in many parts of their range. In order to determine if the current levels of removals are sustainable, information on stock identity and seasonal movements, population parameters, abundance, and the magnitude of removals is required. Although substantial progress has been made to improve our knowledge of these parameters in the last decade, significant gaps still exist. After reviewing the available data for each sub-population in the North Atlantic, it is clear that the information required to assess the status of harbour porpoise populations is still not available for most areas. Attempts have been made to assess the status of harbour porpoise based on trends in sightings or, in areas where information on abundance and bycatch are available, on models using arbitrary criteria and/or theoretical estimates of potential population growth. Detailed case-specific population models have been proposed but are not yet available.

Asymmetry in the skull of the harbour porpoise Phocoena phocoena (L.) and its relationship to sound production and echolocation

1988 ◽  
Vol 66 (2) ◽  
pp. 399-402 ◽  
Author(s):  
D. B. Yurick ◽  
D. E. Gaskin
Keyword(s):  
North Atlantic ◽  
North Pacific ◽  
Sound Production ◽  
East Coast ◽  
Harbour Porpoise ◽  
Phocoena Phocoena ◽  
The North ◽  
The North Atlantic ◽  
The North Pacific ◽  
Precocious Development

Cranial asymmetry in the harbour porpoise Phocoena phocoena (L.) was studied using a series of 115 skulls obtained from animals from both sides of the North Atlantic and the east coast of the North Pacific. The degree of sinistrad asymmetry or "skew" did not differ significantly between these three populations. Contrary to an earlier report in the literature, skew was not found to be correlated with skull length or, by implication, age. This result is in accord with the necessity for precocious development of the nasal sac complex and associated structures in this species, which inhabits an environment in which the aural and acoustic faculties are of paramount importance.

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.

scholarly journals The Effect of Venom of Egyptian Spitting Cobra Naja nubiae on Vascular Permeability of Hepatic and Renal Tissues

2021 ◽  
Vol 9 (1) ◽  
pp. 22-25
Author(s):  
Asmaa Saad Mahmoud Shokhba ◽  
Mohamed A. Abdel-Rahman ◽  
Mohammed Alaa El-Deen A. Omran ◽  
Nahla Soliman El-Shenawy
Keyword(s):  
Body Weight ◽  
Vascular Permeability ◽  
Saline Solution ◽  
Public Awareness ◽  
Control Group ◽  
Albino Rats ◽  
Colorimetric Determination ◽  
Crude Venom ◽  
Treatment Groups ◽  
Renal Vascular

Background: Among venomous elapid snakes, cobras have the highest public awareness, as their venom represents a combination of proteins, peptides, and enzymes that have a range of biochemical and pharmacological roles and are also the main constitutes of biological activity and lethal toxicity. Objectives: The study aimed to evaluate the effect of the venom of Egyptian Spitting Cobra, Naja nubiae, on the vascular permeability based on the extravasation of the azo dye Evans blue (EB) into the tissues of the liver and kidneys of animals envenomed with low (¼ LD50; 0.32 mg/kg) and high (½ LD50; 0.65 mg/ kg) doses at three sampling times (30, 120, 360 min) post-injection of the venom. Methods: Fifty-four adult male Albino rats (8 weeks old and 180±2 0 g body weight) were divided into three main groups (n=6). In the control group, rats were subcutaneously (SC) injected with saline solution. Envenomed groups were SC injected, one group with 0.32 mg/kg and the other group with 0.65 mg/kg body weight of crude venom, respectively. Rats were I.V injected with EB dye 20 minutes before SC injection with saline solution as control animals and with Naja nubiae venom as treatment groups. Results: The results illustrated a high significant rate of EB extravasation to hepatic and renal tissues by the colorimetric determination of EB dye concentration. Conclusion: The venom of Naja nubiae can cause increased hepatic and renal vascular permeability which may explain the inflammatory effect induced by this venom.

Potential Rates of Increase of a Harbour Porpoise (Phocoena phocoena) Population Subjected to Incidental Mortality in Commercial Fisheries

1991 ◽  
Vol 48 (12) ◽  
pp. 2429-2435 ◽  
Author(s):  
Thomas H. Woodley ◽  
Andrew J. Read
Keyword(s):  
Gulf Of Maine ◽  
Intrinsic Rate ◽  
Frequency Equation ◽  
Harbour Porpoise ◽  
Population Increase ◽  
Intrinsic Rate Of Increase ◽  
Natural Mortality ◽  
Phocoena Phocoena ◽  
Rate Of Increase ◽  
Incidental Mortality

We estimated the potential intrinsic rate of increase (r) of the harbour porpoise (Phocoena phocoena) population in the Bay of Fundy and Gulf of Maine using empirical data on reproductive rates (mx) and several hypothetical survival (Ix) schedules. Schedules of Ix, to maximum ages of 12 and 15 yr, were calculated from two potential natural mortality (nx) schedules combined with several schedules of incidental mortality (hx) estimates. The most realistic results were obtained when nx of non-calves were calculated from Caugley's (1966. Ecology 47: 906–918) smoothed age-frequency equation for Himalayan thar (Hemitragus jemlahicus) and applied in conjunction with a range of calf natural mortality estimates, this model indicates that harbour porpoises have a limited capacity for population increase, and populations are unlikely to sustain even moderate levels of incidental mortality (4% of the population per year). Extending the maximum age used in the models from 12 to 15 yr does little to increase estimates of r for the harbour porpoise population, and hence their susceptibility to incidental mortality.

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