Age determination of mysticete whales using 210Pb/226Ra disequilibria

2003 ◽  
Vol 81 (1) ◽  
pp. 21-32 ◽  
Author(s):  
Craig R Kastelle ◽  
Kim EW Shelden ◽  
Daniel K Kimura
Keyword(s):  
Growth Rate ◽  
Age Determination ◽  
Decay Chain ◽  
Individual Growth ◽  
Gray Whale ◽  
Gray Whales ◽  
Slow Growth Rate ◽  
Bowhead Whales ◽  
Radiometric Ages

Accurate age determination is fundamental to the study of population structure and individual growth rates of mysticete whales. Here the disequilibrium between 210Pb and 226Ra in the tympanic bullae of two mysticete whale species was investigated for use as a chronometer. Radiometric ageing depends upon accumulation of the naturally occurring radionuclide 226Ra (exclusive of other 238U decay-chain members) in the bullae and subsequent retention of its progeny 210Pb. Ages are determined from the 210Pb/226Ra activity ratio. Samples were obtained from five gray whales (Eschrichtius robustus) with lengths of 4.5 (a neonate), 7.8, 8.7, 10, and 11.5 m, and two bowhead whales (Balaena mysticetus) with lengths of 12.9 and 17.4 m. In gray whales, radiometric ages were estimated in the three largest whales. In the neonate, the 210Pb/226Ra ratio was above one and was not usable. The 7.8-m gray whale was used to determine the initial 210Pb/226Ra ratio required for age determination. We propose a theory of gray whale bullae growth starting at the fetal stage with an open system (with a 210Pb/226Ra > 1 and a fast growth rate), which transitions by 1 year old to a closed system (with a 210Pb/226Ra << 1 and a slow growth rate). In both bowhead whales, radiometric age could not be estimated because the 210Pb/226Ra ratio was above one. The excess 210Pb in these bullae samples was likely accumulated from the whales' environment via prey, or in the case of the neonate gray whale, across the placental boundary. Our results indicate that the underlying assumptions of the 210Pb/226Ra radiometric ageing method may not hold true in bowhead whales. Successful application of this method to bowhead whales is therefore doubtful.

scholarly journals Age validation of juvenile cod in the Western Baltic Sea

2018 ◽  
Vol 76 (2) ◽  
pp. 430-441 ◽  
Author(s):  
Kate McQueen ◽  
Josef Hrabowski ◽  
Uwe Krumme
Keyword(s):  
Gadus Morhua ◽  
Age Determination ◽  
Individual Growth ◽  
Age Validation ◽  
Length Frequency ◽  
Individual Growth Rate ◽  
Peak Summer ◽  
Age Reading ◽  
Baltic Cod

Abstract The methods routinely used to estimate fish age are often un-validated and susceptible to errors and uncertainties. Despite numerous attempts, age determination of western Baltic cod (WBC, Gadus morhua) using otoliths is still unreliable, predominantly due to inconsistent interpretation of the first translucent zone (TZ). Length-frequencies of undersized (&lt;38 cm) cod collected during 2013–2016 from pound nets near Fehmarn Island were analysed to understand TZ formation patterns. A clear minimum separated two cohorts within the length-frequency samples every year. The length-frequency information was combined with otolith edge analysis to observe the development of TZs in age-0 and age-1 cod otoliths, and to validate the timing of TZ formation, which was consistently completed between September and December. Mean TZ diameters of 4 917 juvenile cod otoliths varied between cohorts (mean diameters of the first TZ: 2.0 ± 0.5 mm; second TZ: 3.9 mm ± 0.5) and TZ diameter variation was found to be related to individual growth rate. The timing of formation of the first TZ was positively related to water temperature, and was confirmed as a “summer ring” rather than a “winter ring”. TZ formation and shallow-water occupancy suggest an influence of peak summer water temperatures on WBC ecology. An age reading guide for juvenile WBC otoliths is provided.

scholarly journals Age and growth of redfish (Sebastes marinus, S. mentella, and S. fasciatus) on the Flemish Cap (Northwest Atlantic)

2004 ◽  
Vol 61 (2) ◽  
pp. 231-242 ◽  
Author(s):  
Fran Saborido-Rey ◽  
Dolores Garabana ◽  
Santiago Cerviño
Keyword(s):  
Growth Rate ◽  
Density Dependence ◽  
Slow Rate ◽  
Age Determination ◽  
Age And Growth ◽  
Northwest Atlantic ◽  
Density Dependent ◽  
Dependent Growth ◽  
Sebastes Mentella

Abstract Age determination of redfish is difficult. In this paper, the ages of Sebastes mentella on the Flemish Cap are validated by following year classes from 1991 to 2000. The criteria used for S. mentella are consistent and coherent. The growth of different year classes is described and compared, and density-dependence is demonstrated to influence the growth rate of the strong 1990 year class, growth of that year class being the slowest of those followed. The slow rate of growth prevented that year class from maturing at the anticipated age. Growth is also compared between sexes, of S. mentella, S. marinus, and S. fasciatus, revealing that females grow faster than males. Finally, growth rate is compared among species. S. marinus grows fastest and S. mentella slowest, although the influence of density-dependent growth in S. mentella needs to be taken into consideration.

scholarly journals Bowhead and Gray Whale Distributions, Sighting Rates, and Habitat Associations in the Eastern Chukchi Sea, Summer and Fall 2009–15, with a Retrospective Comparison to 1982–91

ARCTIC ◽  
2016 ◽  
Vol 69 (4) ◽  
pp. 359 ◽  
Author(s):  
Janet T. Clarke ◽  
Amy S. Kennedy ◽  
Megan C. Ferguson
Keyword(s):  
Habitat Selection ◽  
Chukchi Sea ◽  
Habitat Associations ◽  
Bowhead Whale ◽  
Line Transect ◽  
Gray Whale ◽  
Depth Zone ◽  
Gray Whales ◽  
Bowhead Whales ◽  
Preferred Habitat

We analyzed data from line-transect aerial surveys for marine mammals conducted in the eastern Chukchi Sea (67˚–72˚ N, 157˚–169˚ W) in July to October of 2009–15 to investigate bowhead and gray whale distributions, behaviors, sighting rates, and habitat selection preferences, the last of which allowed direct comparison with results from data collected in this area in 1982–91. Bowhead whales use the eastern Chukchi Sea primarily for migrating between the Beaufort Sea and the Bering Sea, while gray whales use the area to feed on locally abundant benthic amphipods and other prey. Bowhead whales were observed during all survey months and were distributed up to 300 km offshore west and southwest of Point Barrow, Alaska, but without a defined migratory corridor in either summer (July-August) or fall (September-October). Bowhead whale sighting rates (whales per km on effort) were highest in the shelf/trough (51–200 m North) depth zone in the northeastern Chukchi Sea in both summer and fall. This pattern was reflected in habitat selection ratios, which found bowhead whales in summer and fall selecting primarily shelf/trough habitat in the northeastern Chukchi Sea, with shelf habitat (36 – 50 m) being preferred secondarily. Gray whales were observed in all survey months and were distributed primarily within ~95 km of shore between Point Barrow and Icy Cape in the northeastern Chukchi Sea, and about 60–115 km southwest of Point Hope in the southern Chukchi Sea. In both summer and fall, gray whale sighting rates and habitat selection ratios were highest in the shelf/trough (51–200 m South) depth zone in the southern Chukchi Sea. In the northeastern part of the study area, gray whale sighting rates and habitat selection ratios both identified coastal habitat (≤ 35 m) as preferred habitat in summer and shelf/trough (51–200 m North) as preferred habitat in fall. Distribution and habitat associations of bowhead and gray whales remained similar over the 34-year time span with one exception: gray whale preference for shelf/trough habitat in the southern Chukchi Sea is now evident throughout summer and fall, whereas three decades ago gray whale preference for that area was limited to fall only.

Age determination and individual growth rate of Microtus oeconomus mehelyi based on live-trapping

Biologia ◽  
2019 ◽  
Vol 74 (5) ◽  
pp. 487-492
Author(s):  
Veronika Hulejová Sládkovičová ◽  
Dávid Žiak ◽  
Peter Miklós ◽  
Ondrej Kameniar ◽  
Ľudovít Kocian
Keyword(s):  
Growth Rate ◽  
Age Determination ◽  
Individual Growth ◽  
Microtus Oeconomus ◽  
Live Trapping ◽  
Individual Growth Rate

scholarly journals MECHANISMS OF INCREASED RESISTANCE OF BACTERIA TO ANTIMICROBIALS IN BIOFILM

2010 ◽  
Vol 3 (2) ◽  
pp. 3-11
Author(s):  
Dubravka Milanov ◽  
Nataša Čubrak ◽  
Jelena Petrović ◽  
Sava Lazić
Keyword(s):  
Growth Rate ◽  
Inhibitory Concentration ◽  
Slow Growth ◽  
Standard Test ◽  
Patient Treatment ◽  
Genetic Transfer ◽  
Slow Growth Rate ◽  
Enhanced Resistance ◽  
Biofilm Community

The most striking advantage of bacteria residing in biofilm is enhanced resistance to biocide including antibiotics and disinfectants. Biocides are 100% efficient in killing cells in suspension but there are not efficient in destroying bacteria from biofilm community. Mechanisms of increased resistance of bacteria in biofilm to antibiotics is not understood. Some factors alone or in combination are considered to be responsible such as restricted penetration of antibiotics into a biofilm, slow growth rate of biofilm cells, possible expression of certain resistance genes, increased rate of genetic transfer. The standard test for estimating the minimum bactericidal and minimum inhibitory concentration is not applicable for bacteria grown in biofilm. Nowadays, the apparatus for determination of Minimal Biofilm Eradication Concentration (MBEC) has been developed. Determining MBEC helps to select appropriate antibiotics for patient treatment, to identify new antimicrobials targeting biofilm and to track the possible future development of antibiotic resistance against biofilm drugs.

Analysis of Fibronectin and TGF-β1 Immunoexpression to Determination of Wound Vitality in Wistar Rats (Rattus norvegicus)

2015 ◽  
Vol 1 (1) ◽  
Author(s):  
Nita Novita ◽  
Hasrayati Agustina ◽  
Bethy S. Hernowo ◽  
Abdul H. Hassan
Keyword(s):  
Rattus Norvegicus ◽  
Wistar Rats ◽  
Age Determination ◽  
Scientific Field ◽  
Wound Age ◽  
Forensic Practice ◽  
Randomized Design ◽  
Completely Randomized Design ◽  
Tgf Β1

Wound examination is indispensable in forensic practice. The scientific field of wound age determination has advanced progressively during recent years.The purpose of this study was to determine the differences of fibronectin and TGF-β1 expression in both antemortem and postmortem wounds. This study was an experimental with completely randomized design.  The skin wounds (vital and postmortem) were taken from fourty Wistar rats and divided into 10 groups of rats. Immunohistochemical staining was performed to determine the differences between antemortem and postmortem wounds. The result showed that in 30 minutes after antemortem wound infliction, all of samples showed weak reactivity for fibronectin and TGF-β1 (100%).  In first hour after wound infliction, 3 samples (75%) showed weakly positive and 1 sample (25%) strongly positive for fibronectin and TGF-β1.  In 2 hour after wound infliction, 1 sample (25%) showed weakly positive and 3 sample (75%) strongly positive for fibronectin and TGF-β1.  In 3 and 4 hour after wound infliction, all of samples strongly positive for fibronectin and TGF-β1.  In postmortem wound, all of samples showed negativity for fibronectin and TGF-β1. In conclusion, fibronectin and TGF-β1 may be useful in the determination of wound vitality. Keywords: wound, fibronectin, TGF-β1, vitality

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