Age and stock structure of gemfish (Rexea solandri) in New Zealand waters

1999 ◽  
Vol 50 (2) ◽  
pp. 103 ◽  
Author(s):  
P. L. Horn ◽  
R. J. Hurst
Keyword(s):  
Growth Parameters ◽  
Age Determination ◽  
Natural Mortality ◽  
Stock Structure ◽  
Von Bertalanffy ◽  
Length Frequency ◽  
Frequency Distributions ◽  
The North ◽  
Spawning Areas

Age determination of gemfish by counting hyaline zones in otoliths was validated by following the progression of modes in length–frequency distributions and the progression of strong and weak year classes in age–frequency distributions. Length–frequency and otolith samples were examined from four areas (west Northland, east Northland and Bay of Plenty, Wairarapa coast, and the Stewart- Snares shelf). Age–frequency distributions and von Bertalanffy growth parameters were calculated and compared between areas. Two gemfish stocks are indicated on the basis of patterns of year class strengths, trends in commercial landings and likely spawning areas; one off the east and north of the North Island, and another off the west and south of the South Island. Estimates of natural mortality are presented for the two stocks.

Age estimation of barracouta (Thyrsites atun) off southern New Zealand

2002 ◽  
Vol 53 (8) ◽  
pp. 1169 ◽  
Author(s):  
P. L. Horn
Keyword(s):  
New Zealand ◽  
Validation Study ◽  
Age Estimation ◽  
Growth Parameters ◽  
Age Determination ◽  
Von Bertalanffy ◽  
Commercial Catch ◽  
Frequency Distributions

Age determination of barracouta (Thyrsites atun) by counting translucent zones in whole otoliths was validated by examining the number of zones in otoliths from consecutive juvenile modes and following the progression of a strong year class in age-frequency distributions. Readings from whole otoliths, rather than otolith sections, do not result in under-ageing of this species. The ageing interpretation was supported by the progression of a length mode in commercial catch samples over 5 years. The available data indicated a wide variation in year class strengths between years, a characteristic that was very useful in the validation study. Von Bertalanffy growth parameters were calculated, separately by sex, for barracouta from the Southland shelf, New Zealand. Female barracouta reach a significantly larger size than males.

Demographics of the endemic and threatened small cyprinid Pethia setnai from the Northern Western Ghats, India

2020 ◽  
Vol 71 (7) ◽  
pp. 810
Author(s):  
M. SriHari ◽  
Y. Gladston ◽  
S. M. Ajina ◽  
G. B. Sreekanth ◽  
Rajeev Raghavan ◽  
...  
Keyword(s):  
Western Ghats ◽  
Growth Parameters ◽  
Local Population ◽  
Natural Mortality ◽  
Von Bertalanffy ◽  
Fishing Mortality ◽  
Length Frequency ◽  
Growth Coefficient ◽  
First Time ◽  
The Western Ghats

The indigo barb Pethia setnai is a threatened small cyprinid endemic to the Western Ghats biodiversity hotspot of India. In this study, the length–weight relationship and length–frequency-based population dynamics of this species, which are important prerequisites for effective fisheries management, were investigated for the first time based on specimens collected from the Mhadei River in the northern part of the Western Ghats. Estimated von Bertalanffy growth parameters were as follows: theoretical maximum length, L∞, 70.88 mm; growth coefficient, k, 1.50 year–1; and theoretical age at length 0, t0, –0.016 years. Natural mortality of P. setnai was higher than fishing mortality, and the present exploitation level (0.37) was less than 60% of the predicted maximum exploitation, suggesting that the species is not exploited to a level that is detrimental to the local population.

Age and growth of two commercially imported sharks (Carcharhinus tilstoni and C. sorrah) from Northern Australia

1988 ◽  
Vol 39 (4) ◽  
pp. 417 ◽  
Author(s):  
S Davenport ◽  
JD Stevens
Keyword(s):  
Growth Parameters ◽  
Age And Growth ◽  
First Year ◽  
Shark Species ◽  
Von Bertalanffy ◽  
Northern Australia ◽  
Length Frequency ◽  
Frequency Distributions ◽  
Gill Net ◽  
First Year Of Life

The age and growth of Carcharhinus tilstoni and C. sorrah, the two most abundant shark species in commercial gill-net catches off northern Australia, were investigated by the examination of vertebral rings. Corroborating evidence for age and growth estimates was obtained from length-frequency distributions and tag-recapture data. To aid validation of these estimates, tetracycline was injected into sharks at the time of tagging. Growth is relatively rapid in the first year of life: vertebral ageing indicated 17 cm growth in total length (TL) for C. tilstoni and about 20 cm for C. sorrah during the first year after birth. By the time the sharks are 5 years old, growth has declined to 8-10 cm per year in C. tilsoni and 5 cm per year or less in C. sorrah. The von Bertalanffy growth parameters for C. tilstoni are L∞ = 194.2, K = 0.14, t0 = -2.8 for females, and L∞ = 165.4, K = 0.19, t0 = -2.6 for males; for C. sorrah the parameters are L∞ = 123.9, K = 0.34, t0 = -1.9 for females, and L∞ = 98.4, K = 1.17, t0 = -0.6 for males. The greatest recorded ages for C. tilstoni were 12 years for females and 8 years for males, and for C. sorrah, 7 years for females and 5 years for males. Sexual maturity is reached early: at 3 to 4 years in C. tilstoni and 2 to 3 years in female C. sorrah.

scholarly journals Temporal variation, growth and natural mortality of two species of mojarras (Perciformes: Gerreidae) from a tropical coastal lagoon: La Carbonera, Yucatan, Mexico

2013 ◽  
Vol 5 ◽  
pp. 57
Author(s):  
José Luis Bonilla-Gómez ◽  
Maribel Badillo-Alemán ◽  
Alfredo Gallardo-Torres ◽  
Xavier Chiappa-Carrara
Keyword(s):  
Seasonal Variation ◽  
Frequency Analysis ◽  
Coastal Lagoon ◽  
Growth Parameters ◽  
Model Parameters ◽  
Natural Mortality ◽  
Von Bertalanffy ◽  
Length Frequency ◽  
Tropical Coastal Lagoon ◽  
Length Frequency Analysis

This study reports seasonal variation, growth parameters and natural mortality for Eucinostomus gula and Eucinostomus argenteus inhabiting La Carbonera, a tropical coastal lagoon on the northwestern coast of theYucatan Peninsula, Mexico. Specimens were collected between April 2009 and March 2010. A total of 2700organisms of E. gula (> 80% in rainy season ) and 1577 organisms of E. argenteus (>50% in dry season)were collected during the study period. Length-weight relationship (LWR) obtained was W = 8.323E-03Lt2.92 in E. argenteus and W = 7.314E-03 Lt2.92 in E. gula. Growth parameters of von Bertalanffy growthfunction (VBGF) by length frequency analysis were in E. argenteus: L∞ = 13.65 cm, k = 0.54 year-1 and t0= - 0.37 years; and in E. gula: L∞ = 12.60 cm, k = 0.68 year-1 and t0 = - 0.28 years. Additionally, estimatednatural mortality in E. gula was 1.50 year-1 and in E. argenteus was 1.9 year-1. This study presents the firstestimation for both species of model parameters, growth performance index and mortality for the Yucatan Peninsula, which is relevant for the proper implementation of conservation measures for E. gula and E. argenteus in an important coastal zone of the Yucatan Peninsula.Se reportan la variación temporal, los parámetros de crecimiento y la mortalidad natural para Eucinostomus gula y Eucinostomus argenteus que habitan en la laguna costera tropical La Carbonera, al noroeste de la península de Yucatán, México. Los especímenes fueron recolectados entre abril de 2009 a marzo de 2010. Un total de 2 700 organismos de E. gula (> 80% en la estación lluviosa) y 1 577 organismos de E. argenteus (> 50% en la estación seca) fueron recolectados durante el período de estudio. Se determinó la relación peso-longitud (RPL) como: P = 8.323E-03 Lt 2.92 en E. argenteus y P = 7.314E-03  Lt2.92 en E. gula.  Para E. argenteus, los parámetros de crecimiento de la ecuación de crecimiento de von Bertalanffy (ECVB) fueron: L∞ = 13.65 cm,  k = 0.54 año-1 y t0 = - 0.37 años; mientras que para E. gula fueron: L∞ = 12.60 cm, k = 0.68 año-1 y t0 = - 0.28 años. La mortalidad natural en E. gula fue 1.50 año-1 y en E. argenteus fue 1.9 año-1. Este estudio presenta la primera estimación para ambas especies de los modelos de crecimiento, el índice del desempeño de crecimiento y la mortalidad natural para la península de Yucatán, lo que es relevante para la adecuada implementación de medidas de conservación de E. gula y E. argenteus en una valiosa zona costera de la península de Yucatán.

Age determination and growth of the smalltail shark, Carcharhinus porosus, from northern Brazil

1998 ◽  
Vol 49 (7) ◽  
pp. 705 ◽  
Author(s):  
Rosangela Lessa ◽  
Francisco Marcante Santana
Keyword(s):  
Growth Parameters ◽  
General Pattern ◽  
Age Determination ◽  
Age And Growth ◽  
Von Bertalanffy ◽  
Length Frequency ◽  
Northern Brazil ◽  
Late Maturity ◽  
Males And Females ◽  
Length Frequency Data

Age and growth of C. porosus was estimated from seasonally formed marks in vertebrae of 504 specimens (30.0–101.0 cm total length), and from length–frequency data from 1128 individuals (29.4–120.5 cm). Estimated von Bertalanffy growth parameters were: from observed length-at-age, L∞ 125.1 cm, K 0.101 year-1 and t0 –2.89 year; from back-calculated lengths, L∞ 136.4 cm, K 0.077 year-1, t0 –3.27 year; and from length–frequency analysis, L∞ 131.0, K 0.080 and t0 –3.40. Growth did not differ significantly between sexes. Males and females were mature at 71.0 and 70.0 cm, respectively, corresponding to 6 years old. The largest shark aged from vertebrae was a 12-year-old female (101.0 cm). Growth rates calculated from mean observed lengths were 7.0 cm year-1 for the first four years and 4.0 cm year-1 after maturity. Lee’s phenomenon was not apparent. The annulus forms from September to January. Parameters derived from back-calculated lengths were considered to best describe growth. Like most carcharhinids, C. porosus follows the general pattern of K-selected species, exhibiting slow growth, late maturity and low fecundity. Resumo. A idade e o crescimento de C. porosus foram estimados a partir de marcas sazonais em vértebras de 504 indivíduos (30.0–101.0 cm comprimento total) e através de distribuição de freqÜências de comprimentos de 1128 indivíduos (29.4–120.5 cm). Os parâmetros de von Bertalanffy obtidos com comprimentos observados na captura foram: L∞ 125.1 cm, K 0.101 ano –1 e t0 –2.89 anos; com comprimentos retrocalculados: L∞ 136.4 cm, K 0.077 ano-1, t0 –3.27 anos, e da distribuição de freqÜências de comprimentos obteve-se: L∞ 131.0 cm, K 0.080 ano-1 e t0 –3.40. O crescimento não difere entre sexos. Machos e fêmeas são maduras com 71 e 70 cm, respectivamente, correspondendo a idade de 6 anos. O maior espécime cuja idade foi estimada das vértebras tinha 12 anos (101.0 cm). As taxas de crescimento calculadas dos comprimentos médios observados foram 7.0 cm ano-1 para os primeiros quatro anos e 4.0 cm ano-1 após a maturidade. O fenômeno de Lee não ocorreu. O anel se forma entre setembro e janeiro. Os parâmetros obtidos do retroclculo descreveram melhor o crescimento. Como muitos carcharhinideos, C. porosus segue o padrão das espécies da seleção K, exibindo crescimento lento, maturidade tardia e baixa fecundidade.

scholarly journals Temporal variation, growth and natural mortality of two species of mojarras (Perciformes: Gerreidae) from a tropical coastal lagoon: La Carbonera, Yucatan, Mexico

2013 ◽  
Vol 5 ◽  
pp. 57
Author(s):  
José Luis Bonilla-Gómez ◽  
Maribel Badillo-Alemán ◽  
Alfredo Gallardo-Torres ◽  
Xavier Chiappa-Carrara
Keyword(s):  
Seasonal Variation ◽  
Frequency Analysis ◽  
Coastal Lagoon ◽  
Growth Parameters ◽  
Model Parameters ◽  
Natural Mortality ◽  
Von Bertalanffy ◽  
Length Frequency ◽  
Tropical Coastal Lagoon ◽  
Length Frequency Analysis

This study reports seasonal variation, growth parameters and natural mortality for Eucinostomus gula and Eucinostomus argenteus inhabiting La Carbonera, a tropical coastal lagoon on the northwestern coast of theYucatan Peninsula, Mexico. Specimens were collected between April 2009 and March 2010. A total of 2700organisms of E. gula (> 80% in rainy season ) and 1577 organisms of E. argenteus (>50% in dry season)were collected during the study period. Length-weight relationship (LWR) obtained was W = 8.323E-03Lt2.92 in E. argenteus and W = 7.314E-03 Lt2.92 in E. gula. Growth parameters of von Bertalanffy growthfunction (VBGF) by length frequency analysis were in E. argenteus: L∞ = 13.65 cm, k = 0.54 year-1 and t0= - 0.37 years; and in E. gula: L∞ = 12.60 cm, k = 0.68 year-1 and t0 = - 0.28 years. Additionally, estimatednatural mortality in E. gula was 1.50 year-1 and in E. argenteus was 1.9 year-1. This study presents the firstestimation for both species of model parameters, growth performance index and mortality for the Yucatan Peninsula, which is relevant for the proper implementation of conservation measures for E. gula and E. argenteus in an important coastal zone of the Yucatan Peninsula.Se reportan la variación temporal, los parámetros de crecimiento y la mortalidad natural para Eucinostomus gula y Eucinostomus argenteus que habitan en la laguna costera tropical La Carbonera, al noroeste de la península de Yucatán, México. Los especímenes fueron recolectados entre abril de 2009 a marzo de 2010. Un total de 2 700 organismos de E. gula (> 80% en la estación lluviosa) y 1 577 organismos de E. argenteus (> 50% en la estación seca) fueron recolectados durante el período de estudio. Se determinó la relación peso-longitud (RPL) como: P = 8.323E-03 Lt 2.92 en E. argenteus y P = 7.314E-03  Lt2.92 en E. gula.  Para E. argenteus, los parámetros de crecimiento de la ecuación de crecimiento de von Bertalanffy (ECVB) fueron: L∞ = 13.65 cm,  k = 0.54 año-1 y t0 = - 0.37 años; mientras que para E. gula fueron: L∞ = 12.60 cm, k = 0.68 año-1 y t0 = - 0.28 años. La mortalidad natural en E. gula fue 1.50 año-1 y en E. argenteus fue 1.9 año-1. Este estudio presenta la primera estimación para ambas especies de los modelos de crecimiento, el índice del desempeño de crecimiento y la mortalidad natural para la península de Yucatán, lo que es relevante para la adecuada implementación de medidas de conservación de E. gula y E. argenteus en una valiosa zona costera de la península de Yucatán.

Application of the otolith weight – age relationship for the pilchard, Sardinops sagax neopilchardus

1995 ◽  
Vol 52 (4) ◽  
pp. 657-664 ◽  
Author(s):  
W. J. Fletcher
Keyword(s):  
Maximum Size ◽  
Steady Increase ◽  
Average Weight ◽  
Fish Length ◽  
Natural Mortality ◽  
Length Frequency ◽  
Age Classes ◽  
Frequency Distributions ◽  
Southwestern Australia ◽  
Sardinops Sagax

Adult pilchard (Sardinops sagax neopilchardus) from southwestern Australia held in fish cages for 1 year showed minimal increase in mean length but a steady increase in mean otolith weight (1.61–1.83 mg); this increase (0.22 mg) closely parallels the previously calculated mean difference between adjacent age classes (0.24 mg). Modes in otolith weight frequency distributions of fishery-caught pilchards, previously suggested as corresponding with separate year classes, generally persisted and progressed through subsequent samples. By contrast, fish length frequency distributions of these samples showed no consistent modal progression. The average weight of otoliths for year classes 2–8 were used to calculate growth rates: following sexual maturity, at age 2, males grew to a significantly smaller maximum size than females (L∞ = 162 and 172 mm respectively). The otolith weight – age relationship, validated by following a cohort of unusually low abundance as it moved through the fishery, indicated that recruitment to the fishery generally began at age 2 but was not complete until age 4. These data have been successfully used in forecasting the catch rate of the fishery up to 2 years in advance and providing an estimate of the rate for natural mortality of 0.43.

scholarly journals POPULATION DYNAMICS OF MALAYAN LEAF FISH (Pristolepisgrooti Blkr.) IN RANAU LAKE, SOUTH SUMATRA

2018 ◽  
Vol 24 (2) ◽  
pp. 125
Author(s):  
Sevi Sawetri ◽  
Subagdja Subagdja ◽  
Dina Muthmainnah
Keyword(s):  
Mortality Rate ◽  
Growth Parameters ◽  
Total Mortality ◽  
Natural Mortality ◽  
Fishing Mortality ◽  
Frequency Data ◽  
Length Frequency ◽  
Lake Ecosystems ◽  
Exploitation Rate ◽  
Length Frequency Data

The Malayan leaf fish or locally named as kepor (Pristolepis grooti) is one of important biotic components in Ranau Lake ecosystems. This study aimed to estimate population dynamic and exploitation rate of kepor in Ranau Lake, South Sumatera. The population parameters are estimated based on length frequency data which were collected in March to October 2013. Growth parameters and fishing mortality rates were calculated using FiSAT software package. The results showed that kepor’s growth was negative allometric, which tended to gain length faster than weight. Kepor population was dominated (42%) by individual length of 10.0 to 11.0 cm. Predicted length infinity (L) was 17.28 cm with high value of growth rates (K) of 1.4 year-1. The natural mortality rate (M) is 2.57 year-1, the fishing mortality rate (F) is 5.36 year-1 and total mortality rate (Z) is 7.93 year-1. The exploitation rate of Malayan leaf fish in Ranau Lake (E = 0.68 year-1) has passed the optimum score.  

Modeling population dynamics and nonstationary processes of difficult-to-age fishery species with a hierarchical Bayesian two-stage model

2019 ◽  
Vol 76 (12) ◽  
pp. 2199-2214 ◽  
Author(s):  
Yan Li ◽  
Laura M. Lee ◽  
Jason Rock
Keyword(s):  
North Carolina ◽  
Population Dynamics ◽  
Natural Mortality ◽  
Hierarchical Bayesian ◽  
Stage Model ◽  
Survey Analysis ◽  
Two Stage ◽  
The North ◽  
Fishery Species

Modeling population dynamics and establishing a comprehensive population assessment for fishery species that are difficult to age have been challenging. Determination of age for such species is still an unresolved issue or is at best uncertain. Catch-survey analysis does not require full age information but can still provide a comprehensive population assessment. It was extended to incorporate multiple surveys and multiple sources of uncertainties within the statistical catch-at-age framework in the applications to crustaceans. Here, we further generalize and extend the multiple survey catch-survey analysis into a hierarchical Bayesian two-stage model by applying the hierarchical Bayesian approach. The hierarchical Bayesian approach can sufficiently incorporate uncertainty and expert opinions in parameter estimation. We developed a series of models with different assumptions for natural mortality and catchability, including nonstationary (i.e., time-varying) assumptions. We evaluated model robustness to these assumptions and compared population dynamics estimates and population status determination. We demonstrated the application of the hierarchical Bayesian two-stage model using the North Carolina blue crab (Callinectes sapidus) example. In this example, estimation of population size and fishing mortality and determination of population status were robust to the natural mortality and catchability assumptions. The North Carolina blue crab population is less likely to have nonstationary catchability or nonstationary natural mortality. Its natural mortality is more likely to vary by stage than by sex or over time.

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 (<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.

Sign in / Sign up

Export Citation Format

Share Document