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 Changes in baseline growth and maturation parameters of Northwest Atlantic porbeagle, Lamna nasus, following heavy exploitation

2007 ◽  
Vol 64 (1) ◽  
pp. 19-29 ◽  
Author(s):  
Rachel M Cassoff ◽  
Steven E Campana ◽  
Sigmund Myklevoll
Keyword(s):  
Growth Rate ◽  
Growth Response ◽  
Growth Models ◽  
Fork Length ◽  
Likelihood Ratio Tests ◽  
Age At Maturity ◽  
Northwest Atlantic ◽  
Density Dependent ◽  
Growth Changes ◽  
Dependent Growth

We tested for density-dependent changes in growth and maturation of Northwest Atlantic porbeagle (Lamna nasus) after the population declined by 75%–80% from fishing. Vertebrae and reproductive data collected from the virgin (1961–1966) and exploited (1993–2004) populations were analysed to test for differences in growth rate and age and length at maturity between the time periods. We detected significant differences between reparameterized von Bertalanffy growth models for each period, using likelihood ratio tests. Beyond an age of 7 years, mean length at age was greater during 1993–2004 than during 1961–1966. Between 1961–1963 and 1999–2001, length at maturity decreased in males (from 179 to 174 cm curved fork length (CFL)) and was invariant in females (216 cm CFL), whereas age at maturity declined in both males (from 8 to 7 years) and females (from 19 to 14 years). An analysis of porbeagle temperature associations indicated that sharks occupied comparable temperature conditions during the mid-1960s and 1990s, ruling out the possibility of temperature-induced growth changes. The observed increase in growth rate and decrease in age at maturity following exploitation support the hypothesis of a compensatory density-dependent growth response.

Density-Dependent Growth Adaptation Kinetics in 3T 3 Cell Populations Following Sudden [Ca2+] and Temperature Changes. A Comparison with SV40-3T3 Cells

1979 ◽  
Vol 34 (3-4) ◽  
pp. 279-283 ◽  
Author(s):  
Jürgen van der Bosch ◽  
Ilse Sommer ◽  
Heinz Maier ◽  
Willy Rahmig
Keyword(s):  
Growth Rate ◽  
Cell Density ◽  
Cell Number ◽  
Cell Populations ◽  
3T3 Cells ◽  
Density Dependent ◽  
Cell Densities ◽  
Dependent Growth ◽  
Growth Adaptation ◽  
Stationary Cell

Abstract Lowered extracellular [Ca2+] causes low growth rates and low stationary cell densities in 3T3 cell cultures as compared to physiological [Ca2+]. Under otherwise constant conditions the extra­ cellular [Ca2+] determines a stable stationary cell density, which can be readied by increase of net cell number or decrease of net cell number, depending on cell density at the time of [Ca2+] adjustment. SV40-3T3 cells do not show this [Ca2+] dependency. At 39 °C 3T3 and SV40-3T3 cell populations show an increased growth rate at low cell densities as compared to cell populations at 35 °C. Approaching the stationary density the growth rate of both cell sorts is reduced faster at 39 °C than at 35 °C, leading to lower stationary cell densities at 39 °C than at 35 °C. A temperature change from 39 °C to 35 °C or in the opposite direction can affect the stationary cell density of 3T3 cell populations only if applied before reduction of growth rate by density-dependent growth-inhibiting principles has taken place.

Optimal Thinning of a Year-Class with Density-Dependent Growth

1986 ◽  
Vol 43 (4) ◽  
pp. 889-892 ◽  
Author(s):  
Rögnvaldur Hannesson
Keyword(s):  
Density Dependence ◽  
Optimal Harvesting ◽  
Early Date ◽  
Density Dependent ◽  
Moderate Density ◽  
Class A ◽  
Dependent Growth ◽  
The Impact ◽  
Harvesting Costs

I consider the impact of density-dependent growth on the optimal harvesting of a year-class of fish. In general, density dependence makes "thinning" of the year-class a desirable strategy. Moderate density dependence implies that thinning should be gradual, even in the case of zero harvesting costs where the optimal harvesting strategy would otherwise be instantaneous harvesting. Strong density dependence calls for an immediate thinning at an early date, in the case of zero harvesting costs.

scholarly journals Age determination and growth of Atlantic redfish (Sebastes marinus and S. mentella): bias and precision of age readers and otolith preparation methods

2005 ◽  
Vol 62 (4) ◽  
pp. 655-670 ◽  
Author(s):  
Christoph Stransky ◽  
Sif Gudmundsdóttir ◽  
Thorsteinn Sigurdsson ◽  
Svend Lemvig ◽  
Kjell Nedreaas ◽  
...  
Keyword(s):  
Stock Assessment ◽  
Age Determination ◽  
Growth Curves ◽  
Age And Growth ◽  
Preparation Methods ◽  
Irminger Sea ◽  
Coefficients Of Variation ◽  
Commercial Species ◽  
Almost All

Abstract Age determination of Atlantic redfish (Sebastes spp.) has proven difficult and has led to inconsistent age and growth estimates in the past. Using otoliths of the two major commercial species, golden redfish (Sebastes marinus) and deep-sea redfish (S. mentella), a series of exchange schemes was carried out to assess bias and precision of age readings between four readers and between two preparation methods. Considerable bias between readers and moderate precision were observed for the S. marinus readings, especially for ages >20 years, with coefficients of variation (CV) of 7.7–12.0% and average percent error (APE) of 5.4–8.5%. Agreement between readers increased from 17–28% to 45–61% when allowing deviations of ±1 year, and to 80–92% with ±3 years tolerance. The age of S. marinus determined from broken and burnt otoliths was estimated to be slightly lower than when the age of the same individuals was determined from thin-sectioned otoliths. The bias and precision estimates obtained from the S. mentella material were generally poorer than for S. marinus (CV 8.2–19.1%, APE 5.8–13.5%), but similar to reported values for other long-lived fish species. Better than 50% agreement was only achieved with ±3 years tolerance. Growth rates differed significantly between species, confirming slower growth for S. mentella. For S. marinus, only one reader comparison revealed significantly different growth functions, whereas almost all S. mentella reader pairs showed significant differences in growth curves. Section and break-and-burn readings of S. marinus did not differ significantly. Average ages of around 9–10 years were determined for juvenile S. mentella 24–30 cm long, which were likely to have migrated from East Greenland into the Irminger Sea, based on earlier observations. As some of the error in the age determinations presented could be attributed to interpretation differences between readers, further intercalibration of redfish ageing is urgently needed in order to provide consistent input data for stock assessment.

Remarks on Age and Growth Rate Determination of Amazonian Trees

IAWA Journal ◽  
1989 ◽  
Vol 10 (2) ◽  
pp. 133-145 ◽  
Author(s):  
Roland E. Vetter ◽  
Paulo C. Botosso
Keyword(s):  
Growth Rate ◽  
Amazon Basin ◽  
Cambial Activity ◽  
Age And Growth ◽  
Specific Data ◽  
X Ray ◽  
Diameter Increment ◽  
Dry Seasons ◽  
Amazonian Trees

Specific data and comments are given on age and growth rate determination in trees of the Brazilian Amazon basin, based on longterm observation and research of diameter increment, radiocarbon dating, microscopic wood structure, and gamma- and X-ray densitometry; special attention is given to species of the unflooded Terra Firrne forest. Annual dry seasons in eastern Amazonia provoke periodical cambial activity which may be measured as variation in girth increment and is recorded in the wood anatomy as well as its density. Gamma radiation densitometry is discouraged because of poor results. X-ray densitometry and the radiocarbon method are promising but must be refined. Irregular specific climatic events should be considered to be possible natural marks.

scholarly journals Stronger density-dependent growth of Japanese sardine with lower food availability: Comparison of growth and zooplankton biomass between a historical and current stock-increase period in the western North Pacific

2021 ◽  
Author(s):  
Yasuhiro Kamimura ◽  
Kazuaki Tadokoro ◽  
Sho Furuichi ◽  
Ryuji Yukami
Keyword(s):  
Density Dependence ◽  
Food Availability ◽  
North Pacific ◽  
Western North Pacific ◽  
Fish Population ◽  
Japanese Sardine ◽  
Density Dependent ◽  
Mesozooplankton Biomass ◽  
Current Period ◽  
Dependent Growth

Density dependence is a fundamental concept for fish population dynamics. Although density-dependent growth and maturity among older juveniles and adults is important for regulating fish population size and for fisheries management, the mechanism of density dependence for marine fishes remains unclear. Here, we examined changes in Japanese sardine growth with increasing abundance beginning in the 2010s and how the current pattern of density-dependent growth differs from that of a previous stock-increase period from the 1970s to early 1980s. During the current period of increasing abundance, mean standard length has already dropped to the lowest level yet observed and growth has declined more sharply with increased abundance than in the 1970s and 1980s. Mesozooplankton biomass in July in the summer feeding grounds was also lower during the current period. Therefore, our results suggest that summer food availability in the western North Pacific controls the strength of density-dependent growth. A lower carrying capacity for Japanese sardine could account for the stronger density dependence of growth observed in the 2010s; this indicates that future Japanese sardine abundance might not increase as much as in the 1980s unless food availability improves.

scholarly journals Density dependence in the camelid Vicugna vicugna: the recovery of a protected population in Chile

Oryx ◽  
2002 ◽  
Vol 36 (2) ◽  
pp. 118-125 ◽  
Author(s):  
C. Bonacic ◽  
D. W. Macdonald ◽  
J. Galaz ◽  
R. M. Sibly
Keyword(s):  
Growth Rate ◽  
Population Growth ◽  
Density Dependence ◽  
Primary Productivity ◽  
Carrying Capacity ◽  
Population Growth Rate ◽  
Census Data ◽  
South American ◽  
Density Dependent ◽  
Vicugna Vicugna

The vicuña Vicugna vicugna is a wild South American camelid. Following over-exploitation, which brought the species to the brink of extinction in Chile in the 1960s, the population was protected. Since 1975 the population has been censused annually, generating one of the most extensive long-term census databases for any South American mammal. In this paper we use these data, and measures of environmental parameters, to describe the population growth trend of the species and to estimate carrying capacity. Our results indicate that the vicuña has been protected successfully in northern Chile. The census data reveal that, following protection, the population displayed logistic growth between 1975 and 1992. Population growth rate declined linearly with population size, which indicates a degree of density dependence. Density independent factors, such as rainfall, may also have been important. The principal density dependent effect observed was that birth rate declined in those family groups with the most breeding females. The carrying capacity of the study area was estimated from the census data and from models based on precipitation and local primary productivity. Using the census data, an estimation of carrying capacity as the asymptote of the fitted logistic curve suggested that the vicuña population should reach approximately 26,000 vicuñas, whereas estimation when the population growth rate was equated to zero gave a carrying capacity of c. 22,000. Coe's method based on local precipitation predicted 31,000 vicuña, whereas Lavenroth's method based on local primary productivity predicted 26,000 vicuña. In reality, the census data showed that the population peaked at 22,463 vicuñas in 1990. The results are discussed in relation to the need for better census techniques and the implications of density dependent effects for the management of the vicuña in Chile.

scholarly journals Roles of density-dependent growth and life history evolution in accounting for fisheries-induced trait changes

2016 ◽  
Vol 113 (52) ◽  
pp. 15030-15035 ◽  
Author(s):  
Anne Maria Eikeset ◽  
Erin S. Dunlop ◽  
Mikko Heino ◽  
Geir Storvik ◽  
Nils C. Stenseth ◽  
...  
Keyword(s):  
Life History ◽  
Density Dependence ◽  
Time Series Data ◽  
Life History Evolution ◽  
Series Data ◽  
Ecological Processes ◽  
Arctic Cod ◽  
Density Dependent ◽  
History Evolution ◽  
Dependent Growth

The relative roles of density dependence and life history evolution in contributing to rapid fisheries-induced trait changes remain debated. In the 1930s, northeast Arctic cod (Gadus morhua), currently the world’s largest cod stock, experienced a shift from a traditional spawning-ground fishery to an industrial trawl fishery with elevated exploitation in the stock’s feeding grounds. Since then, age and length at maturation have declined dramatically, a trend paralleled in other exploited stocks worldwide. These trends can be explained by demographic truncation of the population’s age structure, phenotypic plasticity in maturation arising through density-dependent growth, fisheries-induced evolution favoring faster-growing or earlier-maturing fish, or a combination of these processes. Here, we use a multitrait eco-evolutionary model to assess the capacity of these processes to reproduce 74 y of historical data on age and length at maturation in northeast Arctic cod, while mimicking the stock’s historical harvesting regime. Our results show that model predictions critically depend on the assumed density dependence of growth: when this is weak, life history evolution might be necessary to prevent stock collapse, whereas when a stronger density dependence estimated from recent data is used, the role of evolution in explaining fisheries-induced trait changes is diminished. Our integrative analysis of density-dependent growth, multitrait evolution, and stock-specific time series data underscores the importance of jointly considering evolutionary and ecological processes, enabling a more comprehensive perspective on empirically observed stock dynamics than previous studies could provide.

scholarly journals Age and growth rate estimations of the commercially fished gastropod Buccinum undatum

2018 ◽  
Vol 75 (6) ◽  
pp. 2129-2144 ◽  
Author(s):  
Philip R Hollyman ◽  
Simon R N Chenery ◽  
Melanie J Leng ◽  
Vladimir V Laptikhovsky ◽  
Charlotte N Colvin ◽  
...  
Keyword(s):  
Growth Rate ◽  
Fishery Management ◽  
Isotope Analysis ◽  
Age Determination ◽  
Growth Curves ◽  
Growth Function ◽  
Age And Growth ◽  
Growth Equation ◽  
Buccinum Undatum ◽  
The United Kingdom

Abstract Calculating age and growth rate for the commercially important whelk, Buccinum undatum in the aid of fishery management has historically been undertaken using growth rings on the organic operculum. This is difficult due to their poor readability and confusion between two different sets of growth lines present. Recent work presented the calcium carbonate statolith as an alternative for age determination of B. undatum. Here we compare the use of statoliths and opercula, comparing their readability and creating growth curves for three distinct populations across the United Kingdom. Using these data, we also test the most appropriate growth equation to model this species. Lastly, we use oxygen isotope analysis of the shells to assign accurate ages to several individuals from each site. These data were used to test the accuracy of statolith and operculum ages. Statoliths, whilst more time consuming to process have improved clarity and accuracy compared with the opercula. This improved readability has highlighted that a Gompertz growth function should be used for populations of this species, when in past studies, von Bertalanffy is often used. Statoliths are a viable improvement to opercula when assessing B. undatum in the context of fishery monitoring and management.

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