scholarly journals Growth increment periodicity in the shell of the razor clam <i>Ensis directus</i> using stable isotopes as a method to validate age

2013 ◽  
Vol 10 (7) ◽  
pp. 4741-4750 ◽  
Author(s):  
J. F. M. F. Cardoso ◽  
G. Nieuwland ◽  
R. Witbaard ◽  
H. W. van der Veer ◽  
J. P. Machado
Keyword(s):  
Cross Sections ◽  
Age Determination ◽  
Growth Increment ◽  
Annual Growth ◽  
Threshold Temperature ◽  
Growth Line ◽  
Razor Clam ◽  
Oxygen And Carbon Isotope ◽  
Reconstructed Temperature ◽  
Correct Estimation

Abstract. To evaluate the role of the razor clam Ensis directus in Dutch coastal waters, understanding its population dynamics is important. As such, the age structure of the population forms a key parameter. Accurate age determination in bivalve shells is not always straightforward due to the difficulty of interpreting externally visible growth lines. In the present paper, we aimed at validating the seasonality in growth line formation using visual techniques in combination with stable oxygen and carbon isotope analyses (δ18O and δ13C). High δ18O values in the shell coincided with growth marks on the external surface of the valve and in acetate peels of the shell's cross section. Most shell δ18O samples were assigned to the months from June to September. From November to March no samples were retrieved, indicating that the shell did not grow. The lowest reconstructed temperature (6.3 °C) suggests that ~ 6 °C may be the threshold temperature for growth. Nevertheless, most of the reconstructed values fell above 14.5 °C, indicating that growth occurred mainly in the summer at relatively high temperatures. Shell δ13C profiles followed a more or less seasonal cycle, but no direct relationship could be made between δ13C values and annual growth lines. Although counting external annual growth lines led to a correct estimation of age and consequently of growth rates, we recommend analysing acetate peels of cross sections to support the distinction between annual lines and disturbance lines.

scholarly journals Growth increment periodicity in the shell of the razor clam <i>Ensis directus</i> using stable isotopes as a method to validate age

2013 ◽  
Vol 10 (3) ◽  
pp. 4303-4330
Author(s):  
J. F. M. F. Cardoso ◽  
G. Nieuwland ◽  
R. Witbaard ◽  
H. W. van der Veer ◽  
J. P. Machado
Keyword(s):  
Cross Sections ◽  
Age Determination ◽  
Growth Increment ◽  
Annual Growth ◽  
Threshold Temperature ◽  
Growth Line ◽  
Razor Clam ◽  
Oxygen And Carbon Isotope ◽  
Reconstructed Temperature ◽  
Correct Estimation

Abstract. To evaluate the role of the razor clam Ensis directus in Dutch coastal waters, assessment and understanding its population dynamics is important. As such, the age structure of the population forms a key parameter. Accurate age determination in bivalve shells is not always straightforward due to the difficulty of interpreting externally visible growth lines. In the present paper, we aimed at validating the seasonality in growth line formation using visual techniques in combination with stable oxygen and carbon isotope analyses (δ18O and δ13C). High δ18O values in the shell coincided with growth marks on the external surface of the valve and in acetate peels of the shell's cross section. Most shell δ18O samples were assigned to the months June to September. From November to March no samples were retrieved indicating that the shell did not grow. The lowest reconstructed temperature (6.1 °C) suggests that ~6 °C may be the threshold temperature for growth. Nevertheless, most of the reconstructed values fell above 14.5 °C indicating growth occurred mainly in the summer at relatively high temperatures. Shell δ13C profiles followed a more or less seasonal cycle but no direct relationship could be made between δ13C values and annual growth lines. Although counting external annual growth lines led to a correct estimation of age and consequently of growth rates, we recommend analysing acetate peels of cross-sections to support the distinction between annual lines and disturbance lines.

scholarly journals Age, growth and mortality of Sciaena umbra (Sciaenidae) in the Gulf of Tunis

2018 ◽  
Vol 82 (1) ◽  
pp. 17 ◽  
Author(s):  
Inès Chater ◽  
Ahlem Romdhani-Dhahri ◽  
Jean Louis Dufour ◽  
Kélig Mahé ◽  
Nadia Chakroun-Marzouk
Keyword(s):  
Cross Sections ◽  
Growth Function ◽  
Growth Increment ◽  
Total Weight ◽  
Marginal Analysis ◽  
Positive Allometry ◽  
Total Length ◽  
Gulf Of Tunis ◽  
Von Bertalanffy Growth Function ◽  
Log Linear

The growth and mortality of the brown meagre, Sciaena umbra from the Gulf of Tunis, were investigated using a sample of 276 specimens, ranging from 15.3 to 49.2 cm total length and from 43 to 1565 g total weight. Specimens were collected from artisanal fisheries between October 2008 and September 2011. Otoliths were extracted, thin cross-sections were realized and radii were measured. The log-linear morphometric relationships between total length-total weight and total length-otolith radius were significant (p < 0.05), showed positive allometry (b=3.15) and isometry (b=0.90), respectively. The marginal analysis suggested that only one growth increment was deposited per year. The maximum age of the brown meagre was 22 years for males and 31 years for females. The fit of the von Bertalanffy growth function was significantly different between sexes (p

scholarly journals Growth Intercept Methods for Predicting Site Index in White Pine Plantations in the Glaciated Areas of Ohio

2006 ◽  
Vol 23 (3) ◽  
pp. 176-183 ◽  
Author(s):  
James H. Brown
Keyword(s):  
Site Index ◽  
Growth Increment ◽  
Annual Growth ◽  
Site Quality ◽  
Soil Horizon ◽  
Regression Equations ◽  
White Pine ◽  
Annual Increment ◽  
Growth Intercept ◽  
Annual Growth Increment

Abstract Growth intercept (GI) techniques were evaluated for estimating site quality in white pine stands planted on old-field sites in the Wisconsin-aged glaciated areas of northern and western Ohio. Correlations between growth of trees below the breast high (bh) annual growth increment andheight growth from bh and above were not statistically significant. Site index estimates were made using age at bh and height from the bh annual growth increment to the growing tip. Three-year and 5-year growth beginning 3 years above the bh annual increment and 10-year growth beginning oneinternode above bh were significantly more correlated with height than were intercepts beginning at bh. In multiple regression equations developed for predicting site index, 3-, 5- and 10-year intercepts, along with age at bh, accounted for 76, 77, and 80%, respectively, of the variationin tree heights and 35-year site indices varied from 60 to 83 ft. Combining clay content of the B2 soil horizon with GI and age increased the variation accounted for by 3-, 5-, and 10-year GI equations to 79, 78, and 81%, respectively, and the improvement in site index estimatesover those using GIs alone was not more than ±2 ft within any given GI measurement.

Age estimation for young bowhead whales (Balaena mysticetus) using annual baleen growth increments

2008 ◽  
Vol 86 (6) ◽  
pp. 525-538 ◽  
Author(s):  
S. C. Lubetkin ◽  
J. E. Zeh ◽  
C. Rosa ◽  
J. C. George
Keyword(s):  
Growth Parameters ◽  
Age Determination ◽  
Population Level ◽  
Exponential Model ◽  
Growth Increment ◽  
Balaena Mysticetus ◽  
Nonlinear Mixed Effects Model ◽  
Bowhead Whales ◽  
Growth Increments ◽  
Age Estimates

We compiled age estimates and baleen plate δ13C data from 86 bowhead whales ( Balaena mysticetus L., 1758). We used previous whale age estimates based on aspartic acid racemization (AAR) and corpora counts to extend the use of δ13C data for age determination from cycle counting to a modified exponential model using annual baleen growth increments. Our approach used the growth increment data from individual whales in a nonlinear mixed effects model to assess both population-level and whale-specific growth parameters. Although age estimates from baleen-based models become less precise as the whales age, and baleen growth and length near steady state, the growth increment model shows promise in estimating ages of bowhead whales 10–13.5 m long with baleen lengths <250 cm, where other techniques are less precise or the data are scarce. Ages estimated using the growth increment data from such whales ranged from 6.4 to 19.8 years.

Seasonal growth pattern in the lichen Pseudocyphellaria berberina in north-western Patagonia

2004 ◽  
Vol 36 (6) ◽  
pp. 435-444 ◽  
Author(s):  
Mayra S. CALDIZ
Keyword(s):  
Growth Increment ◽  
Annual Growth ◽  
Seasonal Growth ◽  
Epiphytic Lichen ◽  
Growth Increments ◽  
The Mean ◽  
Individual Trees ◽  
Nothofagus Dombeyi ◽  
North Western ◽  
Annual Growth Increment

Seasonal growth increments (%) were measured in the foliose epiphytic lichen Pseudocyphellaria berberina in north-western Patagonia. Growth was determined by measuring increase in weight (expressed as percentage of the original biomass) in transplanted thalli. Transplants were either hung freely from wooden frames or attached to tree trunks in a Nothofagus dombeyi forest and then weighed every three months between January 2001 and April 2003. The influence on growth increment of treatment, donor thallus, temperature, and absolute and relative humidity was analysed. Mean annual growth increment after two years, in both treatments was 12±1·07% (±SE). Growth increment was greatest in winter and lowest in summer; the mean winter growth increment was 6±0·50%, representing half of the annual growth, whereas most of the remaining growth occurred during both spring and autumn. Growth increments were similar for freely-hanging lichens and for the transplants attached to tree trunks. Individual trees had no consistent effect on growth while the donor thallus had a significant effect in the first season which then diminished, indicating acclimation in the transplants. Initial transplant weight had no influence on final cumulative growth, nor was there any consistent correlation between one season and another in the growth of transplants. Both transplantation methods proved to be useful for experiments on the growth of P. berberina.

scholarly journals Validation of age determination using otoliths of the European anchovy (Engraulis encrasicolus L.) in the Bay of Biscay

2016 ◽  
Vol 67 (7) ◽  
pp. 951 ◽  
Author(s):  
A. Uriarte ◽  
I. Rico ◽  
B. Villamor ◽  
E. Duhamel ◽  
C. Dueñas ◽  
...  
Keyword(s):  
Age Groups ◽  
Age Determination ◽  
Annual Growth ◽  
Bay Of Biscay ◽  
Opaque Zone ◽  
Zone Formation ◽  
European Anchovy ◽  
Spawning Time ◽  
Hyaline Zone ◽  
European Anchovy Engraulis Encrasicolus

Validation of the age determination procedure using otoliths of European anchovy in the Bay of Biscay was achieved by monitoring very strong year-classes in successive spring catches and surveys, as well as the seasonal occurrence of edge types. Historical corroboration of the ageing method was obtained by cross-correlation between successive age groups by year-classes in catches and surveys (1987–2013). Summary annual growth in length is also presented. Yearly annuli consist of a hyaline zone (either single or composite) and a wide opaque zone, disrupted occasionally by some typical checks (mainly at age-0 and age-1 at peak spawning time). Age determination, given a date of capture, requires knowledge of the typical annual growth pattern of otoliths, their seasonal edge formation by ages and the most typical checks. Most opaque growth occurs in summer and is minimal (translucent) in winter. Opaque zone formation begins earlier in younger fish (in spring), and this helps distinguish age-1 from age-2+.

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