Données préliminaires sur la présence de lignes d'arrêt de croissance périostiques dans la mandibule du marsouin commun, Phocoena phocoena (L.), et leur utilisation comme indicateur de l'âge

1982 ◽  
Vol 60 (11) ◽  
pp. 2557-2567 ◽  
Author(s):  
V. de Buffrenil
Keyword(s):  
Bone Growth ◽  
Harbour Porpoise ◽  
Phocoena Phocoena ◽  
Growth Layer ◽  
Thin Sections ◽  
Hematoxylin Staining ◽  
Layer Groups ◽  
Age Determinations

Sharply defined growth lines are revealed by hematoxylin staining of thin sections of mandibular periosteal bone of the harbour porpoise, Phocoena phocoena (L.). The comparison of these lines to dentinal growth layer groups (GLG) suggests that they are deposited at the rate of one per annum. In this species, bone growth lines allow more reliable and much more complete age determinations than do dentinal GLG's. The actual longevity of the harbour porpoise, as determined by growth lines in bone, is at least 21 years.

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.

Age estimation of marine tucuxi dolphins (Sotalia fluviatilis) in south-eastern Brazil

2003 ◽  
Vol 83 (1) ◽  
pp. 233-236 ◽  
Author(s):  
M.C. de O. Santos ◽  
S. Rosso ◽  
R.M.A. Ramos
Keyword(s):  
Body Length ◽  
Growth Curve ◽  
Age Estimation ◽  
East Coast ◽  
Von Bertalanffy ◽  
Growth Layer ◽  
Thin Sections ◽  
Eastern Brazil ◽  
Sotalia Fluviatilis ◽  
Layer Groups

This study reports the age estimation of marine tucuxi dolphins (Sotalia fluviatilis) found dead along the south-east coast of Brazil (24°40′S–25°30′S). The investigated specimens were collected from August 1995 to December 1998. Ages were estimated through the number of Growth Layer Groups (GLGs) from decalcified and stained thin sections of teeth. A total of 36 individuals was investigated. Estimated ages of marine tucuxis varied from zero to 29 years. The growth curve was attained from a modification of the von Bertalanffy equation applied to body length and age data. It was possible to estimate the total length of 97·8 cm in newborns, physical maturity was attained at seven years of age, and an asymptotic length of 179·8 cm.

scholarly journals Two techniques of age estimation in cetaceans: GLGs in teeth and earplugs, and measuring the AAR rate in eye lens nucleus

2017 ◽  
Vol 10 ◽  
Author(s):  
Nynne H Nielsen ◽  
Gísli A. Víkingsson ◽  
Steen H. Hansen ◽  
Susanne Ditlevsen ◽  
Mads Peter Heide-Jørgensen
Keyword(s):  
Aspartic Acid ◽  
North Atlantic ◽  
Von Bertalanffy ◽  
Phocoena Phocoena ◽  
Growth Layer ◽  
Balaenoptera Acutorostrata ◽  
Aspartic Acid Racemization ◽  
Minke Whales ◽  
Fin Whales ◽  
Layer Groups

The ages of three species of cetaceans were estimated by counting the growth layer groups (GLG) and measuring the aspartic acid racemization rate (kAsp) by what is referred to as the Aspartic Acid Racemization (AAR) technique. Data on kAsp and the D/L ratio of aspartic acid at birth [(D/L)0] in North Atlantic common minke whales (Balaenoptera acutorostrata) are presented along with data on fin whales (B. physalus) and harbour porpoises (Phocoena phocoena) already published by Nielsen et al. (2012). The kAsp specific for minke whales was 1.40 x 10-3 yr-1 (SE ± 0.00005) and the (D/L)0 was 0.0194 (SE ± 0.0012). The correlation of GLG age and D/L ratio for all three species was highly significant; however, the correlation coefficient varied greatly (fin whales: R2 = 0.59, p <0.0001; minke whales: ­R2=0.96, P <0.0001; harbour porpoises: ­R2=0.36, P <0.0001). Asymptotic body length for all three species was estimated by a von Bertalanffy growth model on both the GLG and AAR techniques, and showed no difference.

GROWTH LAYER GROUPS (GLGs) IN THE TEETH OF AN ADULT BELUKHA WHALE (DELPHINAPTERUS LEUCAS) OF KNOWN AGE: EVIDENCE FOR TWO ANNUAL LAYERS

1987 ◽  
Vol 3 (1) ◽  
pp. 14-21 ◽  
Author(s):  
Arthur D. Goren ◽  
Paul F. Brodie ◽  
Stephen Spotte ◽  
G. Carleton Ray ◽  
H. W. Kaufman ◽  
...  
Keyword(s):  
Delphinapterus Leucas ◽  
Growth Layer ◽  
Layer Groups

scholarly journals Growth of the skull of the bottlenose dolphin, Tursiops truncatus, in the Southwest Atlantic Ocean

10.5597/00229 ◽  
2017 ◽  
Vol 11 (1-2) ◽  
pp. 199-211 ◽  
Author(s):  
André Silva Barreto
Keyword(s):  
Bottlenose Dolphin ◽  
Tursiops Truncatus ◽  
Growth Equation ◽  
Growth Layer ◽  
Southwest Atlantic ◽  
Development Patterns ◽  
Skull Measurements ◽  
The One ◽  
Layer Groups ◽  
Mature Size

Defining the age of attainment of physical maturity is important for many studies, including identification of stocks, populations or species. In order to identify the age when the skull of the bottlenose dolphin, Tursiops truncatus, reaches maturity, skulls of fifty-three specimens found stranded along the coasts of southern Brazil, Uruguay and northern Argentina (27o35’S, 48o34’W-36o49’S, 55o19’W) were analyzed. Sixty skull measurements were taken to compare the growth rate of the different functional apparatuses. Age was estimated by counts of growth layer groups in the dentine of decalcified, stained longitudinal sections of teeth. Von Bertalanffy’s equation was applied to assess the growth and determine the age at maturity of each apparatus. Generally the maturation of skull starts at age two and stabilizes at age five, and the age of reaching the mature size varies amongst different characters. The braincase is the most precocious apparatus, while the feeding is the one that last stabilizes. The development patterns observed for the hearing, vision and breathing apparatuses were similar. Statistic analysis revealed significant differences among the ages at maturity, but not for von Bertalanffy’s growth equation parameters for each functional apparatus. For the studied population it is suggested that skulls can be considered mature in animals with more than five years. 

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.

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.

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