scholarly journals Age and growth variability of the yellow clam (Mesodesma mactroides) in two populations from Argentina: implications under climate change

2020 ◽  
Vol 98 (7) ◽  
pp. 481-494
Author(s):  
M.C. Risoli ◽  
A. Baldoni ◽  
J. Giménez ◽  
B.J. Lomovasky

Morphometric relationships and age and growth rates of the yellow clam (Mesodesma mactroides Reeve, 1854 = Amarilladesma mactroides (Reeve, 1854)) were compared in two populations from Argentina: Santa Teresita (36°32′00″S) and Mar del Plata (37°57′52″S). The Santa Teresita clams were heavier (shell, soft parts) than the Mar del Plata clams. Cross sections stained with Mutvei’s solution and acetate peels revealed an internal shell growth pattern of well-defined slow-growing translucent bands and alternating fast-growing opaque bands. Translucent bands (clusters) representing external rings were formed mostly during October in both sites, coinciding with gonadal maturation processes and spawning. Data confirm the annual formation of translucent bands in this species. Comparison of growth parameters showed a higher growth rate k and lower maximum age in Mar del Plata (8 years) than in Santa Teresita (9 years), which could be triggered by differences in salinity between localities due to the influence of the Rio de la Plata estuary, which is strongly linked to climate variability. Shell mass condition index and Oceanic Niño Index were negatively correlated, showing the influence of El Niño in shell properties of the species. Considering that events are becoming more intense and frequent, changes in growth rates and shell properties of Santa Teresita’s population could be expected to be more vulnerable under climate change.

1992 ◽  
Vol 43 (5) ◽  
pp. 983 ◽  
Author(s):  
JR Anderson ◽  
AK Morison ◽  
DJ Ray

Transverse thin sections (0.5 mm thick) of sagittal otoliths from 290 Murray cod up to 1400 mm in total length and 47.3 kg in weight were used to establish the age and growth of cod in the lower Murray-Darling Basin, including comparisons of recent (1986-91) and past (1949-51) growth rates and growth in different waters. The maximum estimated age was 48 years. Quantitative and qualitative analysis of the seasonal changes in otolith marginal increments showed that annuli in fish of all ages were laid down each spring, and 1 October was assigned as the birthday. The thin-sectioning method was validated by comparing age estimates for 55 Murray cod from Lake Charlegrark (age 0-21 years), which had been validated by using burnt and polished half-otoliths. The new method had an accuracy of 96.4% and it offers major advantages in ease of preparation, reading, and batch-handling of large numbers of otoliths. The precision of the method, estimated as an average error for four readers, was 5.4% (3.0% after ignoring discrepancies in relation to annuli on otolith edges). There was a linear relationship between otolith weight and fish age and an exponential relationship between otolith weight and fish length. Both otolith length and otolith width reached an asymptote at about 15 years, when fish length also approached its maximum. However, otolith thickness continued to increase throughout the life of the fish and, after about 15 years, contributed most to the increase in otolith weight. This confirmed that otoliths continued to grow in thickness and that annuli were laid down throughout life, and that cod could be aged reliably to the maximum age. The annulus pattern is very clear and distinct, and the reading techniques are fully described, including recognition of 'larval' and 'false' rings. Various differences were found in the growth rates, and the length-weight relationships for males and females, for cod caught in 1986-91 and those caught in 1949-51, and various subpopulations are discussed. The von Bertalanffy growth parameters (all individuals combined) were estimated at L∞ = 1202 mm, k=0.108 and t0= -0.832. The availability of a reliable ageing method provides the first opportunity to determine year of birth and thus to examine the age structure of populations and to effectively manage cod populations that have declined in abundance.


Genetics ◽  
1995 ◽  
Vol 139 (4) ◽  
pp. 1719-1726 ◽  
Author(s):  
P David ◽  
B Delay ◽  
P Berthou ◽  
P Jarne

Abstract Correlations between allozyme heterozygosity and fitness-related traits, especially growth, have been documented in natural populations of marine bivalves. However, no consistent pattern has been exhibited, because heterotic effects on size vary with age and individual growth parameters are generally unknown. No consensus has emerged on the genetic basis of allozyme-associated heterosis. The species studied here, Spisula ovalis, displays annual shell growth lines, which allows us to compute individual age and growth dynamics over the whole life span. Our morphological study was coupled to a protein electrophoresis study at seven polymorphic loci. While the maximum size gained is not related to heterozygosity, the age at half maximum size, t1/2, is significantly negatively correlated with heterozygosity, indicating an heterotic effect on initial growth. The correlation between heterozygosity and size is expected to vanish when age increases, due to the form of the growth function. This decreasing correlation is consistent with previous studies. We compare the relative performances of five linear models to analyze the genetic basis of heterosis. Surprisingly, the largest part of variance in t1/2 is due to additive effects, the overdominant components being much weaker. Heterosis is therefore due to general genomic effects rather than to local overdominance restricted to allozymes or small neighboring chromosomal segments. A significant dependence of individual heterotic contributions of the enzyme loci upon expected heterozygosities, rather than metabolic function, further supports the hypothesis of enzymes acting as markers. General genomic effects can hold only if allozyme heterozygosity is positively correlated with heterozygosity at fitness-related genes scattered throughout the genome. This hypothesis is supported here by heterozygosity correlations between enzymatic loci.


1997 ◽  
Vol 77 (4) ◽  
pp. 1199-1212 ◽  
Author(s):  
E. Jordana ◽  
M. Guillou ◽  
L.J.L. Lumingas

Growth of the echinoid Sphaerechinus granularis from the Gleiian Islands (Brittany, France) was studied by analysis of growth zones in longitudinal cross-sections of interambulacral oral plates. The diameter-at-age data pairs were increased using a back-calculation technique, which allows for a more efficient estimation of von Bertalanffy growth curve parameters. The annual value of the skeletal growth marks agreed with the analysis of the population's size-frequency distributions taken from a previous study. Significant differences in growth and morphological parameters were observed between two populations of the archipelago in close geographical proximity and inhabiting the same type of substratum. These differences, which appear as population phenotypic responses to different hydrodynamic conditions, confirms growth plasticity in S. granularis.


1995 ◽  
Vol 46 (8) ◽  
pp. 1127 ◽  
Author(s):  
BM Wolf ◽  
RWG White

Growth of the queen scallop, Equichlamys bifrons, was examined at one site in the D'Entrecasteaux Channel and two sites in the Huon River estuary (Tasmania) by analysing growth rings on the shell and shell hinge ligament, tagging scallops, and using size-frequency techniques. Regular sampling of scallops revealed that shell growth of E. bifrons is seasonal, commencing in late spring and stopping in late autumn. During the remainder of the year, when the water temperature is below ~13�C, shell growth slows or stops and growth rings are formed on the shell and shell hinge ligament. The growth rings on the shell and hinge ligament of E. bifrons were verified as being annual by studying the growth of marked scallops. Long-term growth patterns were similar for E. bifrons from Middleton (D'Entrecasteaux Channel) and from Deep Bay (Huon River estuary). Tagging data collected over the 1992-93 growing season indicated short-term variation in growth between sites. Size-frequency distributions from Middleton and Deep Bay could not be interpreted because smaller scallops were scarce. Smaller size classes were present at Eggs and Bacon Bay (Huon River estuary) and the size-frequency distribution was resolved into age classes. Reasonable agreement was found between the von Bertalanffy growth parameters obtained from the size frequency, tagging, and growth ring data.


2010 ◽  
Vol 68 (3) ◽  
pp. 507-518 ◽  
Author(s):  
Friedemann Keyl ◽  
Juan Argüelles ◽  
Ricardo Tafur

Abstract Keyl, F., Argüelles, J., and Tafur, R. 2011. Interannual variability in size structure, age, and growth of jumbo squid (Dosidicus gigas) assessed by modal progression analysis. – ICES Journal of Marine Science, 68: . A range of growth rates, longevity, maximum size, and number of annual cohorts have been documented for jumbo squid (Dosidicus gigas). Genetic and phenotypic plasticity have been mentioned as possible sources of the differences in maximum sizes. Here, a large dataset on length frequencies derived from the industrial jig fishery for the species off Peru from 1991 to 2007 was corrected for observation bias introduced by the fishing gear and used to analyse growth-related parameters by modal progression analysis (MPA). Mean growth rates of 33 cohorts varied interannually (11–44 mm month−1), as did longevity (11.1–32.1 months) and mean maximum size (273–1024 mm). Intra-annual difference in growth parameters was not significant. The number of cohorts per year fluctuated between 0 and 6. Fast-growing cohorts with medium longevity and large terminal size were found during moderately cool periods, and long-lived, slow-growing cohorts with small terminal size during extreme ecosystem conditions (El Niño and La Niña). The application of MPA to cephalopod populations has been rejected before, but the results presented suggest that a modified approach is appropriate if it allows for varying growth parameters and includes a correction for observation bias.


2010 ◽  
Vol 67 (1) ◽  
pp. 97-107 ◽  
Author(s):  
Thomas P. Hurst ◽  
Alisa A. Abookire ◽  
Brian Knoth

Understanding the causes of contemporary variation in growth rates can offer insights into the likely consequences of climate change for growth and recruitment of coastal marine fishes. We examined the growth dynamics of age-0 northern rock sole ( Lepidopsetta polyxystra ) over four years in three nurseries at Kodiak Island, Alaska, USA. Following the settlement period, fish were sampled monthly (July–October) with a 3 m beam trawl at fixed-position transects. Postsettlement sizes were positively related to temperatures during the spawning and larval periods, suggesting environmental control of spawning or settlement timing. Summer growth on the nursery grounds varied significantly among sites and years (mean size 32.8–63.1 mm in mid-September), with the Holiday Beach site consistently supporting the fastest growth rates. Contrary to expectations of density dependence and thermal regulation, nursery ground growth rates were not significantly correlated with fish density or water temperatures. The minor contribution of thermal variation to growth rates appears related to the conservative growth strategy and low thermal sensitivity of northern rock sole. These results suggest that climate changes influencing spawning time and larval growth may have larger impacts on first-year growth and recruitment of this species than temperature effects on the growth of nursery-resident juveniles.


2018 ◽  
Vol 68 (2) ◽  
pp. 147-159
Author(s):  
Ali İhsan Eroğlu ◽  
Ufuk Bülbül ◽  
Muammer Kurnaz ◽  
Yasemin Odabaş

AbstractThe present study was designed to compare the life history traits of twoPodarcis muralispopulations located at sites of different elevation. The age at maturity was similar in both populations, whereas longevity was found to be lower in the lowland one (Dereköy). The males and females of both populations had a similar snout-vent length (SVL) and mean age. Sexual size dimorphism (SSD) was weak in the highland population, males being slightly larger than females, whereas a strong male-biased SSD was observed in the lowland one. The growth coefficient (k) and growth rates were similar in both populations. This study indicates that the age at maturation (2-3 years) and growth rates (2.37 mm/year) are similar in two populations ofP. muralisexposed to different climatic and environmental conditions. Longevity was slightly higher in the highland population (16 years) compared to the lowland one (14 years).


Herpetozoa ◽  
2019 ◽  
Vol 32 ◽  
pp. 195-201 ◽  
Author(s):  
Ayşen Günay Arısoy ◽  
Eyup Başkale

In many amphibians, skeletochronology is a reliable tool for assessing individual mean longevity, growth rates and age at sexual maturity. We used this approach to determine the age structure of 162 individuals from two Pelophylax caralitanus populations. All individuals exhibited Lines of Arrested Growth (LAGs) in the bone cross-sections and the average age varied between 4.5 and 5.4 years in both Işıklı and Burdur populations. Although intraspecific age structure and sex-specific age structure did not differ significantly between populations, we found that the Işıklı population had a lower body size in the same age class, had lower growths rates and lower values of survival rates and adult life expectancy than the Burdur population.


2007 ◽  
Vol 58 (9) ◽  
pp. 856 ◽  
Author(s):  
Justin A. Chidlow ◽  
Colin A. Simpfendorfer ◽  
Garry R. Russ

Age and growth parameters of Orectolobus hutchinsi were estimated using micro-radiographs of sectioned vertebrae from 182 wild caught individuals. Two fluorochrome marker dyes, calcein and oxytetracycline, were used to validate the timing and periodicity of vertebral band formation in nine individuals held in the laboratory for between 423 and 472 days. Growth bands were difficult to interpret and final counts were obtained from only 98 (53.8%) individuals ranging in total length (TL) from 63 to 146 cm. The timing of growth band formation in the vertebrae of captive animals had no predictable temporal pattern, with formation occurring during all seasons of the year, making age validation difficult. Growth band formation was hypothesised to be influenced by non-periodic changes in centrum or somatic growth rather than seasonal growth, as observed in many other elasmobranch species. Growth rates of nine O. hutchinsi held in captivity varied considerably, ranging from 3.5 cm year–1 to 13.8 cm year–1 in total length (mean = 7.03 cm year–1). Although the periodicity of vertebral band formation in captive animals did not support a synchronous annual pattern, captive growth rates matched those predicted when an annual band pattern was assumed for wild caught individuals. Von Bertalanffy growth parameters estimated from vertebral analysis assuming an annual banding pattern and a mean size of birth of 24.1 cm were: L∞ = 149.45 cm and K = 0.117 year–1 for both sexes combined. These results illustrate the fundamental importance of validating the periodicity of growth band formation in elasmobranch age and growth studies as it has considerable implications for the management of fisheries that exploit shark and ray species that may exhibit asynchronous growth band deposition.


2018 ◽  
pp. 76-94 ◽  
Author(s):  
I. A. Makarov ◽  
C. Henry ◽  
V. P. Sergey

The paper applies multiregional CGE Economic Policy Projection and Analysis (EPPA) model to analyze major risks the Paris Agreement on climate change adopted in 2015 brings to Russia. The authors come to the conclusion that if parties of the Agreement meet their targets that were set for 2030 it may lead to the decrease of average annual GDP growth rates by 0.2-0.3 p. p. Stricter climate policies beyond this year would bring GDP growth rates reduction in2035-2050 by additional 0.5 p. p. If Russia doesn’t ratify Paris Agreement, these losses may increase. In order to mitigate these risks, diversification of Russian economy is required.


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