Age and growth dynamics of spiny dogfish, Squalus acanthias, in the Adriatic Sea (Eastern Mediterranean Sea)

2016 ◽  
Vol 67 (3) ◽  
pp. 357 ◽  
Author(s):  
Romana Gračan ◽  
Scott A. Heppell ◽  
Gordana Lacković ◽  
Bojan Lazar
Keyword(s):  
Adriatic Sea ◽  
Growth Models ◽  
Eastern Mediterranean ◽  
Growth Dynamics ◽  
Fishing Effort ◽  
Age And Growth ◽  
Percentage Error ◽  
Parameter Estimates ◽  
Spiny Dogfish ◽  
Average Percentage

This research provides the first information on age and growth estimates for the endangered Mediterranean subpopulation of spiny dogfish, a commercially exploited shark, highly sensitive to overexploitation. We collected samples from 206 specimens caught by commercial bottom trawls in the Adriatic Sea, and utilising three ageing protocols achieved good agreement between the readings (average percentage error=1.65%). Four growth models were fitted to length-at-age and weight-at-age data, for each sex separately. The Gompertz growth model produced the statistically best fit resulting in the following parameters: k values for males and females were 0.09 and 0.04 year–1, size-at-birth ranged from 22.9 to 24.1-cm total length, with a theoretical asymptotic length of 103.3cm for males and 173.3cm for females. The age at 50% maturity was 10.5 years for males and 20.1 years for females. The maximum age was estimated at 23 years for males and 36 years for females, with natural mortality estimates of 0.12 for males and 0.07 for females. As a result of reported demographic parameter estimates, high fishing effort and particularly low resilience of the species to exploitation, it is important to produce proper species-specific management strategy for the spiny dogfish in the region.

Stock-specific assessment of precise age and growth in the long-whiskered catfish Sperata aor from the Ganges River

2020 ◽  
Vol 71 (12) ◽  
pp. 1693
Author(s):  
Aafaq Nazir ◽  
M. Afzal Khan
Keyword(s):  
Age And Growth ◽  
Percentage Error ◽  
Specific Information ◽  
Ganges River ◽  
Average Percentage ◽  
Marginal Increment ◽  
Hard Structures ◽  
Average Percentage Error ◽  
Anthropogenic Threats ◽  
The Ganges

Sustainable management of the long-whiskered catfish Sperata aor (Hamilton, 1822) in the Ganges River justifies precise stock-specific information on age and growth. The aim of the present study was to estimate the age and growth of three stocks, namely Narora–Kanpur, Varanasi and Bhagalpur, of S. aor from the Ganges River. Among the hard structures chosen for analysis, vertebrae provided precise age estimates up to 9 years of age in all the three stocks of S. aor based on average percentage error. Edge analysis of vertebrae and marginal increment ratio analysis of sectioned otoliths showed annulus formation once per year during April–June. The von Bertalanffy growth rates showed significant differences between the sexes and among the stocks. The growth coefficient k (0.24–0.30 year–1) showed rapid growth relative to asymptotic length (L∞) in all three stocks. The growth performance index was nearly the same for all three stocks. The results of the present study can be used in formulating scientifically sound management policies in view of anthropogenic threats to the populations of S. aor from the Ganges River.

Application of a 'case-building approach' to investigate the age distributions and growth dynamics of Australian sardine (Sardinops sagax) off South Australia

2007 ◽  
Vol 58 (5) ◽  
pp. 461 ◽  
Author(s):  
P. J. Rogers ◽  
T. M. Ward
Keyword(s):  
Growth Parameters ◽  
South Australia ◽  
Growth Dynamics ◽  
Percentage Error ◽  
Commercial Catch ◽  
Average Percentage ◽  
Daily Increments ◽  
Sardinops Sagax ◽  
Age Structured ◽  
Average Percentage Error

Like many pelagic fish, sardine Sardinops sagax is difficult to age by counting structures in otoliths. Of 12968 whole otoliths analysed in the present study, <25% could be counted with accuracies of greater than ±1 zone. Estimates of average percentage error (APE) were high (11.37%). We used a ‘case building approach’ to corroborate a method for estimating age. Regressions of otolith weight–age from otoliths with high readabilities were used to estimate the age of fish with lower or unreadable otoliths. Growth rates determined from daily increments ranged from 0.36 to 0.75 mm day–1 for larvae and from 0.22 to 0.47 mm day–1 for juveniles. Estimates of von Bertalanffy growth coefficients were k = 0.32–1.07 year–1 and L∞ = 166.96–195.68 mm. Growth parameters estimated during the present study support previous assertions that levels of pelagic production in South Australian (SA) waters lie between those recorded in the predominantly oligotrophic waters off Western Australia (WA) and the productive waters off southern California and South Africa. Disparities in the age distributions of inshore and offshore samples suggest that age data from commercial catch samples may not be representative of the population. This finding has implications for the use of age-structured models to assess of stocks of S. sagax and other small pelagic fishes.

scholarly journals Age and growth of longtail tuna (Thunnus tonggol) in tropical and temperate waters of the central Indo-Pacific

2009 ◽  
Vol 67 (1) ◽  
pp. 125-134 ◽  
Author(s):  
Shane P. Griffiths ◽  
Gary C. Fry ◽  
Fiona J. Manson ◽  
Dong C. Lou
Keyword(s):  
Growth Models ◽  
Fork Length ◽  
Information Criterion ◽  
Growth Increment ◽  
Annual Growth ◽  
Age And Growth ◽  
Parameter Estimates ◽  
Growth Increments ◽  
Significant Difference ◽  
Longtail Tuna

Abstract Griffiths, S. P., Fry, G. C., Manson, F. J., and Lou, D. C. 2010. Age and growth of longtail tuna (Thunnus tonggol) in tropical and temperate waters of the central Indo-Pacific. – ICES Journal of Marine Science, 67: 125–134. Age and growth of longtail tuna (Thunnus tonggol) were assessed by examination of annual growth increments in sectioned sagittal otoliths from 461 fish (238–1250 mm fork length, LF) sampled from tropical and temperate waters in the central Indo-Pacific between February 2003 and April 2005. Edge and microincrement analyses (presumed daily increments) suggest that longtail tuna deposit a single annual growth increment mainly between August and October. Age was, therefore, estimated for all fish by counting assumed annual growth increments. Ages ranged from 154 d to 18.7 years, with most fish being 3–9 years. Five growth models were fitted to length-at-age data, all of which indicated that the species is relatively slow-growing and long-lived. Recaptures of two tagged fish at liberty for 6.2 and 10.5 years support this notion. A bias-corrected form of Akaike's Information Criterion determined that the Schnute–Richards model provided the best fit to length-at-age data, with model parameter estimates (sexes combined) of L∞ = 135.4 cm LF, K = 22.3 year−1, t0 = 0.120 years, δ = 150.0, v = 0.019, and γ = 2.7 × 10−8. There was no significant difference in growth between sexes. The results suggest that longtail tuna grow more slowly and live longer than other tuna species of similar size. Coupled with their restricted neritic distribution, longtail tuna may be vulnerable to overexploitation by fisheries, and caution needs to be exercised in managing the species until more reliable biological and catch data are collected to assess the status of the population.

Growth dynamics of freshwater crocodiles (Crocodylus johnstoni) in the Lynd River, Queensland

2006 ◽  
Vol 54 (6) ◽  
pp. 409 ◽  
Author(s):  
Anton D. Tucker ◽  
Colin J. Limpus ◽  
Keith R. McDonald ◽  
Hamish I. McCallum
Keyword(s):  
Growth Models ◽  
Growth Dynamics ◽  
Interval Data ◽  
Age And Growth ◽  
Data Sets ◽  
Size Dimorphism ◽  
Crocodylus Johnstoni ◽  
Trade Offs ◽  
Capture Recapture ◽  
Australian Freshwater

We analysed growth models for a population of Australian freshwater crocodiles (Crocodylus johnstoni). Competing growth models were tested with two data sets: individuals of known-age, and growth interval data from capture-recapture records. A von Bertalanffy function provided the best empirical fit of several growth models. The estimated asymptotic lengths (snout–vent length of males = 125.3 cm; females = 97.4 cm) agreed well with average lengths of the ten largest males and females in the population. Sexual size dimorphism in this species resulted from a combination of smaller mean length at maturity for females and a subsequent decline in female growth rate. Size dimorphism may result from individual trade-offs in age v. length at maturity as a consequence of sexual selection.

scholarly journals Improved Growth Estimates for Lethrinus harak: Measuring Increments, Adjusting Ages, and Fitting Flexible Growth Models

Fishes ◽  
2018 ◽  
Vol 3 (3) ◽  
pp. 31
Author(s):  
Stephen Midway ◽  
Andrew Ostrowski ◽  
Lindsey West ◽  
Mario Hernandez ◽  
Matthew Robertson
Keyword(s):  
Fishery Management ◽  
Growth Parameters ◽  
Growth Models ◽  
Age And Growth ◽  
Tropical Species ◽  
Parameter Estimates ◽  
Growth Coefficient ◽  
Asymptotic Size ◽  
Age Estimates ◽  
Edge Size

Thumbprint emperor (Lethrinus harak) are a widely distributed, tropical species ranging throughout the Indo-Pacific region. In coastal Tanzania, overfishing is likely occurring and thumbprint emperor are commonly represented in catches. The goal of this study was to estimate age and growth to provide basic life history information that may help inform future management. We sampled a total of n = 55 thumbprint emperors from both fishery-dependent and fishery-independent sources. Annular age estimates were improved with measurements of otolith markings. Fish ages ranged from zero to five years. We also evaluated the addition of otolith edge size (a proxy for fractional age) to age estimation, and fit two von Bertalanffy growth models—one for the whole ages and one for the fractional ages—using a flexible Bayesian framework. Growth parameters were similar between the two models, and ultimately, L ∞ (maximum asymptotic size parameter) estimates were comparable to other published values for the species, although our estimates of K (growth coefficient parameter) were smaller. Robust aging techniques for tropical fishes can provide a foundation for basic fishery management, which would help to sustain the future of this widely distributed fish.

Validated age, growth and reproductive biology of Carcharhinus melanopterus, a widely distributed and exploited reef shark

2013 ◽  
Vol 64 (10) ◽  
pp. 965 ◽  
Author(s):  
Andrew Chin ◽  
Colin Simpfendorfer ◽  
Andrew Tobin ◽  
Michelle Heupel
Keyword(s):  
Life History ◽  
Logistic Model ◽  
Growth Models ◽  
Growth Parameter ◽  
Information Criterion ◽  
Age And Growth ◽  
Parameter Estimates ◽  
Eastern Australia ◽  
Reef Sharks ◽  
Carcharhinus Melanopterus

Inadequate life-history information can compromise management of shark populations. The present study examined the life history of blacktip reef sharks (Carcharhinus melanopterus) from north-eastern Australia with predictions that they would show life-history patterns similar to those of other reef sharks species. Age and growth estimates were derived from vertebrae and five growth models. Males were 543–1390 mm total length (LST) and females were 514–1600 mm LST. Longevity was 10 years (males) and 15 years (females). Chemical marking confirmed annual band pair deposition but indicated probable age underestimation of large individuals. The logistic model was preferred (second-order Akaike information criterion (AICc) weight 0.7536), with growth parameter estimates of length at birth (L0) = 617 mm LST; asymptotic length (L∞) = 1585 mm LST; k (from logistic model) = 0.251 year–1. Males matured at 4.2 years (1050 mm LST) and females at 8.5 years (1335 mm LST), although further verification is needed. Mating and parturition occurred in summer and autumn, females having three or four pups per litter. Data were inconclusive in determining reproductive periodicity. These data contribute to the species management and conservation and suggest that the species may be sensitive to fishing pressure and habitat loss. The study also demonstrated potential complications in using vertebrae to estimate age and growth of chondrichthyan fishes.

Quality control of age data at the Alaska Fisheries Science Center

2005 ◽  
Vol 56 (5) ◽  
pp. 783 ◽  
Author(s):  
Daniel K. Kimura ◽  
Delsa M. Anderl
Keyword(s):  
Quality Control ◽  
Stock Assessment ◽  
Control Programme ◽  
Age And Growth ◽  
Percentage Error ◽  
Science Center ◽  
Average Percentage ◽  
Fisheries Science ◽  
Test For Symmetry ◽  
Average Percentage Error

The Alaska Fisheries Science Center operates a 14-person Age and Growth Program that specialises in the ageing of various groundfish species using otoliths. In 1983, a quality control programme was established whereby a random subsample of 20% of the total of aged samples is re-aged by a second age reader. The purpose of this programme is to assure, to the greatest extent possible, that ages used in stock assessment are based on consistent ageing criteria. This age data is entered into our AGEDATA Microsoft ACCESS™ database where it can be easily updated, corrected and analysed. VISUAL BASIC computer programmes AGREE (a precision estimating programme) and RANGES (an outlier searching programme) were written to routinely analyse age data before data are released to end-users. The statistical relationship between average percentage error and coefficient of variation is described, as well as an interpretation of Bowker’s test for symmetry. Discrepancies between the reader and tester are reconciled while viewing the problematic otoliths using a dual-headed microscope, and reconciled ages are assigned. When necessary, all questionable otoliths in a troublesome sample may be re-aged.

Actuation and dynamic mechanical characteristics of a core free flat dielectric electro-active polymer soft actuator

2020 ◽  
Vol 14 (4) ◽  
pp. 7396-7404
Author(s):  
Abdul Malek Abdul Wahab ◽  
Emiliano Rustighi ◽  
Zainudin A.
Keyword(s):  
Theoretical Model ◽  
Resonance Frequency ◽  
Dynamic Testing ◽  
Experimental Results ◽  
Percentage Error ◽  
Initial Tension ◽  
Average Percentage ◽  
Soft Actuator ◽  
Average Percentage Error ◽  
Mechanical Dynamics

Various complex shapes of dielectric electro-active polymer (DEAP) actuator have been promoted for several types of applications. In this study, the actuation and mechanical dynamics characteristics of a new core free flat DEAP soft actuator were investigated. This actuator was developed by Danfoss PolyPower. DC voltage of up to 2000 V was supplied for identifying the actuation characteristics of the actuator and compare with the existing formula. The operational frequency of the actuator was determined by dynamic testing. Then, the soft actuator has been modelled as a uniform bar rigidly fixed at one end and attached to mass at another end. Results from the theoretical model were compared with the experimental results. It was found that the deformation of the current actuator was quadratic proportional to the voltage supplied. It was found that experimental results and theory were not in good agreement for low and high voltage with average percentage error are 104% and 20.7%, respectively. The resonance frequency of the actuator was near 14 Hz. Mass of load added, inhomogeneity and initial tension significantly affected the resonance frequency of the soft actuator. The experimental results were consistent with the theoretical model at zero load. However, due to inhomogeneity, the frequency response function’s plot underlines a poor prediction where the theoretical calculation was far from experimental results as values of load increasing with the average percentage error 15.7%. Hence, it shows the proposed analytical procedure not suitable to provide accurate natural frequency for the DEAP soft actuator.

scholarly journals Adaptive Neuro-Fuzzy Inference System for Modelling the Effect of Slurry Impacts on PLA Material Processed by FDM

Polymers ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 118
Author(s):  
Bahaa Saleh ◽  
Ibrahem Maher ◽  
Yasser Abdelrhman ◽  
Mahmoud Heshmat ◽  
Osama Abdelaal
Keyword(s):  
Weight Gain ◽  
Fused Deposition Modeling ◽  
Synergetic Effect ◽  
Solid Particles ◽  
Percentage Error ◽  
Inference System ◽  
Average Percentage ◽  
Fused Deposition ◽  
Effect Of Water ◽  
Neuro Fuzzy

In this research, the effect of water-silica slurry impacts on polylactic acid (PLA) processed by fused deposition modeling (FDM) is examined under different conditions with the assistance of an adaptive neuro-fuzzy interference system (ANFIS). Building orientation, layer thickness, and slurry impact angle are considered as the controllable variables. Weight gain resulting from water, net weight gain, and total weight gain are the predicting variables. Results uncover the accomplishment of the ANFIS model to appropriately appraise slurry erosion in correlation with comparing real data. Both experimental and ANFIS results are almost identical with average percentage error less than 5.45 × 10−6. We observed during the slurry impacts tests that all specimens showed an increase in their weights. This weight gain was finally interpreted to the synergetic effect of water absorption and the solid particles fragmentations immersed within the specimens due to the successive slurry impacts.

scholarly journals Age and growth of franciscana dolphins, Pontoporia blainvillei (Cetacea: Pontoporiidae) incidentally caught off southern Brazil and northern Argentina

2010 ◽  
Vol 90 (8) ◽  
pp. 1493-1500 ◽  
Author(s):  
Silvina Botta ◽  
Eduardo R. Secchi ◽  
Mônica M.C. Muelbert ◽  
Daniel Danilewicz ◽  
Maria Fernanda Negri ◽  
...  
Keyword(s):  
Growth Models ◽  
Growth Curves ◽  
Small Sample ◽  
Age And Growth ◽  
Buenos Aires Province ◽  
Von Bertalanffy ◽  
Southern Brazil ◽  
Data Set ◽  
Males And Females ◽  
Pontoporia Blainvillei

Age and length data of 291 franciscana dolphins (Pontoporia blainvillei) incidentally captured on the coast of Rio Grande do Sul State (RS), southern Brazil, were used to fit growth curves using Gompertz and Von Bertalanffy growth models. A small sample of franciscanas (N = 35) from Buenos Aires Province (BA), Argentina, were used to see if there are apparent growth differences between the populations. Male and female franciscana samples from both areas were primarily (78–85%) <4 years of age. The Von Bertalanffy growth model with a data set that excluded animals <1 year of age provided the best fit to data. Based on this model, dolphins from the RS population reached asymptotic length at 136.0 cm and 158.4 cm, for males and females, respectively. No remarkable differences were observed in the growth trajectories of males and females between the RS and BA populations.

Sign in / Sign up

Export Citation Format

Share Document