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.

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.

Supplementary Information on Minke Whale (Balaenoptera acutorostrata) from Newfoundland Fishery

1975 ◽  
Vol 32 (7) ◽  
pp. 985-994 ◽  
Author(s):  
Edward Mitchell ◽  
V. Michael Kozicki
Keyword(s):  
Sexual Maturity ◽  
Supplementary Information ◽  
Von Bertalanffy ◽  
Growth Layer ◽  
Balaenoptera Acutorostrata ◽  
Pregnant Females ◽  
Minke Whales ◽  
Inshore Waters ◽  
Males And Females ◽  
Juvenile Males

Minke whales (Balaenoptera acutorostrata) segregate by age and sex in the inshore waters of Newfoundland. The fishery in Trinity Bay exploited primarily juvenile males and females and pregnant females. Sexual maturity in females is at 24 ft (7.3 m) long and 7.3 earplug growth layers. Over 85% of mature females sampled were pregnant, three were lactating concurrently. A maximum of 14 growth layers was found in earplugs sampled. The ovulation rate was calculated at 0.6 corpora per growth layer. A von Bertalanffy growth curve was fitted to the data.

scholarly journals A Multi-elemental Approach to Identification of Subpopulations of North Atlantic Minke Whales Balaenoptera Acutorostrata

2007 ◽  
Vol 13 (1) ◽  
pp. 84-97 ◽  
Author(s):  
Erik W. Born ◽  
Michael C. S. Kingsley ◽  
Frank F. Rigét ◽  
Rune Dietz ◽  
Per Møller ◽  
...  
Keyword(s):  
North Atlantic ◽  
Balaenoptera Acutorostrata ◽  
Minke Whales

scholarly journals Age estimation of Antarctic minke whales Balaenoptera bonaerensis based on aspartic acid racemization technique

2017 ◽  
Vol 83 (6) ◽  
pp. 947-954
Author(s):  
Genta Yasunaga ◽  
Luis A. Pastene ◽  
Takeharu Bando ◽  
Takashi Hakamada ◽  
Yoshihiro Fujise
Keyword(s):  
Aspartic Acid ◽  
Age Estimation ◽  
Aspartic Acid Racemization ◽  
Minke Whales ◽  
Balaenoptera Bonaerensis

scholarly journals Changes in blood testosterone and progesterone concentrations of the North Atlantic minke whale (Balaenoptera acutorostrata) during the feeding season

2004 ◽  
Vol 61 (2) ◽  
pp. 230-237 ◽  
Author(s):  
Matthías Kjeld ◽  
Árni Alfredsson ◽  
Örn Ólafsson ◽  
Morten Tryland ◽  
Ivar Christensen ◽  
...  
Keyword(s):  
Frequency Distribution ◽  
North Atlantic ◽  
Minke Whale ◽  
Balaenoptera Acutorostrata ◽  
Hunting Season ◽  
P Values ◽  
The North ◽  
Minke Whales ◽  
The North Atlantic ◽  
Cyclic Changes

An opportunity to study seasonal changes of sex hormones in the North Atlantic minke whale (common minke whale, Balaenoptera acutorostrata) arose when we obtained access to fresh postmortem blood samples from 104 females and 83 males. The whales were caught in the North Atlantic during May–September 1992–1995. Serum progesterone (P) and testosterone (T) concentrations were measured and compared with anatomical data. The frequency distribution of female serum P values showed two clusters, one consisting mainly of immature animals and the second of pregnant ones, with mean serum values of about 0.49 ± 0.04 (SE) and 44.2 ± 2.84 nmol·L–1, respectively. The frequency distribution of male serum T did not show any group-specific distribution during the hunting season. The mean serum T value for the males was 0.63 ± 0.13 nmol·L–1. Contrary to earlier reports on the Antarctic minke whale (Balaenoptera bonaerensis), serum T values rose during the hunting season in mature males (p < 0.0001). Serum P values in immature females increased during the season (p = 0.015). This increase agrees with the predominantly annual reproduction cycle of minke whales. Blood sex hormone measurements seem to be useful for detecting cyclic changes and pregnancy of minke whales.

scholarly journals Minke whale abundance estimation from the NASS 1987 and 2001 aerial cue–counting surveys taking appropriate account of distance estimation errors

2009 ◽  
Vol 7 ◽  
pp. 95 ◽  
Author(s):  
David L Borchers ◽  
Daniel G Pike ◽  
Thorvaldur Gunnlaugsson ◽  
Gísli A Víkingsson
Keyword(s):  
Measurement Error ◽  
North Atlantic ◽  
Measurement Errors ◽  
Distance Estimation ◽  
Minke Whale ◽  
Balaenoptera Acutorostrata ◽  
Estimation Errors ◽  
Random Measurement Error ◽  
Minke Whales ◽  
Coastal Shelf

We estimate the abundance of minke whales (Balaenoptera acutorostrata) from the Icelandic coastal shelf aerial surveys carried out as part of the 1987 and 2001 North Atlantic Sightings Surveys (NASS). In the case of the 1987 survey, the probability of detecting animals at distance zero (g(0)) is very close to 1 but there is substantial random measurement error in estimating distances. To estimate abundance from these data, we use methods which assume g(0)=1 but which includea distance measurement error model. In the case of the 2001 survey, measurement errors were sufficiently small to be negligible, and we use double platform methods which estimate g(0) and assume no measurement error to estimate abundance. From the 1987 survey, we estimate abundance to be 24,532 animals, with 95% CI (13,399; 44,916). From the 2001 NASS survey data, minke whale abundance is estimated to be 43,633 animals, with 95% CI (30,148; 63,149).

scholarly journals Harbour porpoises (Phocoena phocoena) and minke whales (Balaenoptera acutorostrata) observed during land-based surveys in The Minch, north-west Scotland

2013 ◽  
Vol 94 (6) ◽  
pp. 1185-1194 ◽  
Author(s):  
Sarah J. Dolman ◽  
Nicola K. Hodgins ◽  
Colin D. MacLeod ◽  
Graham J. Pierce ◽  
Caroline R. Weir
Keyword(s):  
Minke Whale ◽  
Harbour Porpoise ◽  
Phocoena Phocoena ◽  
Balaenoptera Acutorostrata ◽  
Sea State ◽  
Marine Fauna ◽  
Monitoring Method ◽  
North West ◽  
Minke Whales ◽  
Cetorhinus Maximus

The waters off north-west Scotland are known to provide important habitat for the harbour porpoise (Phocoena phocoena) and the minke whale (Balaenoptera acutorostrata). Between October 2008 and April 2011, systematic land-based surveys were carried out to assess the seasonal occurrence, group size and group behaviours of both species in a study area located off Melvaig, near Gairloch. Data were collected on 47 separate days, with a total of 4543 minutes of survey effort (in sea states ≤3) recorded during the spring months and 8204 minutes of effort during the autumn. A total of 189 sightings of marine fauna were recorded, comprising 126 cetacean sightings, 50 seal sightings and 13 sightings of basking sharks (Cetorhinus maximus). Six species of cetacean were identified, with most sightings comprising harbour porpoise (N = 72) or minke whale (N = 38). Harbour porpoise abundance was higher in autumn than in spring and there was a variation between years in numbers of minke whales sighted. In porpoises, sea state and cloud cover both influenced sightings and increasing sea state influenced survey area. Foraging behaviour was exhibited in 13% of harbour porpoise sightings and 34% of minke whale sightings. Results demonstrate a regular occurrence of harbour porpoises and minke whales in nearshore waters off Gairloch. Densities are comparable to boat surveys in the region and so support the use of land-based watches as a potential longer-term monitoring method for these species in coastal waters. Given the regular use of this area by these two European Protected Species, as well as the occurrence of a range of human activities potentially affecting them in the region, it may be appropriate to consider protecting this area for their conservation.

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