Individual growth estimation of Ucides occidentalis (Brachyura, Ocypodidae) in the Gulf of Guayaquil, Ecuador by indirect methods and multi-model selection

Crustaceana ◽  
2016 ◽  
Vol 89 (13) ◽  
pp. 1509-1524 ◽  
Author(s):  
René Zambrano ◽  
E. Alberto Aragón-Noriega ◽  
Gabriela Galindo-Cortes ◽  
Lourdes Jiménez-Badillo ◽  
Manuel Peralta
Keyword(s):  
Growth Models ◽  
Stock Assessment ◽  
Individual Growth ◽  
Sources Of Information ◽  
Indirect Methods ◽  
Frequency Distributions ◽  
Capture Recapture ◽  
Data Source ◽  
Gulf Of Guayaquil ◽  
Growth Estimation

Ucides occidentalis (Ortmann, 1897) is a commercial crab in the Ecuadorian continental coast, however, little knowledge is available about its biology. A very important aspect for stock assessment and fisheries management is the species’ individual growth. In this paper U. occidentalis growth in males and females was determined by indirect methods and the multi-model approach. By Kernel density estimators size frequency distributions were built, separating their Gaussian components by the Bhattacharya’s method. Using modal progression, the cohorts were identified, and one was selected to apply asymptotic, non-asymptotic, and Schnute’s versatile growth models. The best fit model was selected using the Akaike and Bayesian weights. Case 1 of Schnute was the winner model in both sexes, asymptotic in males with cephalothorax width (CW), and , but it was non-asymptotic for females with an inflexion point in 2.49 years that corresponded to 73.72 mm CW. The type of individual growth of this species varies between sexes, which may be linked to reproductive issues; however, we should consider the data source and their impact on the interpretations that we can draw about individual growth. Therefore, for future studies, using other sources of information such as commercial catches or capture-recapture to validate the results presented, is recommended.

scholarly journals Assessing the Potential of Catch-Only Models to Inform on the State of Global Fisheries and the UN’s SDGs

2021 ◽  
Vol 13 (11) ◽  
pp. 6101
Author(s):  
Rishi Sharma ◽  
Henning Winker ◽  
Polina Levontin ◽  
Laurence Kell ◽  
Dan Ovando ◽  
...  
Keyword(s):  
Stock Assessment ◽  
Fishing Effort ◽  
The State ◽  
Sources Of Information ◽  
Ongoing Research ◽  
Traditional Assessment ◽  
Stock Status ◽  
Stock Assessments ◽  
Recent Developments ◽  
Measure Of Performance

Catch-only models (COMs) have been the focus of ongoing research into data-poor stock assessment methods. Two of the most recent models that are especially promising are (i) CMSY+, the latest refined version of CMSY that has progressed from Catch-MSY, and (ii) SRA+ (Stock Reduction Analysis Plus) a recent developments in field. Comparing COMs and evaluating their relative performance is essential for determining the state of regional and global fisheries that may be lacking necessary data that would be required to run traditional assessment models. In this paper we interrogate how performance of COMs can be improved by incorporating additional sources of information. We evaluate the performance of COMs on a dataset of 48 data-rich ICES (International Council for the Exploration of Seas) stock assessments. As one measure of performance, we consider the ability of the model to correctly classify stock status using FAO’s 3-tier classification that is also used for reporting on sustainable development goals to the UN. Both COMs showed notable bias when run with their inbuilt default heuristics, but as the quality of prior information increased, classification rates for the terminal year improved substantially. We conclude that although further COM refinements show some potential, most promising is the ongoing research into developing biomass or fishing effort priors for COMs in order to be able to reliably track stock status for the majority of the world’s fisheries currently lacking stock assessments.

Reference points for the length-based indicator Lmax5% for use in the assessment of data-limited stocks

2019 ◽  
Vol 76 (7) ◽  
pp. 2125-2139 ◽  
Author(s):  
Tanja Miethe ◽  
Yves Reecht ◽  
Helen Dobby
Keyword(s):  
Life Histories ◽  
Stock Assessment ◽  
Reference Points ◽  
Length Frequency ◽  
Frequency Distributions ◽  
Simulation Tools ◽  
Spawning Potential Ratio ◽  
The Mean ◽  
Commercial Sources ◽  
Length Frequency Data

Abstract In the absence of abundance indices from scientific surveys or commercial sources, reliable length frequency data from sampled commercial catches can be used to provide an indirect assessment of fishing mortality. Length-based indicators are simple metrics which describe length frequency distributions. The length-based indicator Lmax5%, the mean length of the largest 5% of individuals in the catch, combined with appropriately selected reference points, can be used to evaluate the presence of very large individuals in the catch and hence determine exploitation level. Using analytical per-recruit models, we derive reference points consistent with a spawning potential ratio of 40%. The reference points depend on the life history parameters for natural mortality, maturity, and growth (M, Lmat, L∞, k, CVL∞). Using available simulation tools, we investigate the sensitivity of the reference points to errors in these parameters and explore the usefulness of particular reference points for management purposes for stocks with different life histories. The proposed reference points are robust to uncertainty in length at first capture, Lc, and take into account the maturation schedule of a species. For those stocks with high M/k ratios (>1), Lmax5%, combined with the appropriate reference point, can be used to provide a data-limited stock assessment.

scholarly journals Comparison of growth models to describe growth from birth to 6 years in a Beninese cohort of children with repeated measurements

BMJ Open ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. e035785
Author(s):  
Shukrullah Ahmadi ◽  
Florence Bodeau-Livinec ◽  
Roméo Zoumenou ◽  
André Garcia ◽  
David Courtin ◽  
...  
Keyword(s):  
Growth Model ◽  
Goodness Of Fit ◽  
Growth Models ◽  
Information Criterion ◽  
Height Growth ◽  
Sub Saharan Africa ◽  
Individual Growth ◽  
Secondary Outcome ◽  
Growth Trajectories ◽  
Best Fitting

ObjectiveTo select a growth model that best describes individual growth trajectories of children and to present some growth characteristics of this population.SettingsParticipants were selected from a prospective cohort conducted in three health centres (Allada, Sekou and Attogon) in a semirural region of Benin, sub-Saharan Africa.ParticipantsChildren aged 0 to 6 years were recruited in a cohort study with at least two valid height and weight measurements included (n=961).Primary and secondary outcome measuresThis study compared the goodness-of-fit of three structural growth models (Jenss-Bayley, Reed and a newly adapted version of the Gompertz growth model) on longitudinal weight and height growth data of boys and girls. The goodness-of-fit of the models was assessed using residual distribution over age and compared with the Akaike Information Criterion (AIC) and Bayesian Information Criterion (BIC). The best-fitting model allowed estimating mean weight and height growth trajectories, individual growth and growth velocities. Underweight, stunting and wasting were also estimated at age 6 years.ResultsThe three models were able to fit well both weight and height data. The Jenss-Bayley model presented the best fit for weight and height, both in boys and girls. Mean height growth trajectories were identical in shape and direction for boys and girls while the mean weight growth curve of girls fell slightly below the curve of boys after neonatal life. Finally, 35%, 27.7% and 8% of boys; and 34%, 38.4% and 4% of girls were estimated to be underweight, wasted and stunted at age 6 years, respectively.ConclusionThe growth parameters of the best-fitting Jenss-Bayley model can be used to describe growth trajectories and study their determinants.

Exploitation status and stock assessment by pseudo-cohort analysis of the bluefish, Pomatomus saltatrix, in the Gulf of Gabes (Tunisia)

2007 ◽  
Vol 87 (5) ◽  
pp. 1315-1319 ◽  
Author(s):  
Khalifa Dhieb ◽  
Mohamed Ghorbel ◽  
Othman Jarboui ◽  
Abderrahmen Bouaïn
Keyword(s):  
Stock Assessment ◽  
Cohort Analysis ◽  
Fishing Effort ◽  
Individual Growth ◽  
Eastern Coast ◽  
Pomatomus Saltatrix ◽  
Gulf Of Gabes ◽  
Gulf Of Gabès ◽  
Exploitation Status ◽  
The One

The bluefish, Pomatomus saltatrix, is quite abundant in the Gulf of Gabes, off the south-eastern coast of Tunisia. It is commercially exploited by artisanal gears and trawlers all year round, and by purse seine nets from May to August (bluefish fishery season). Catches of bluefish, in the period 1996–2004 fluctuated between 365.6 t and 1240.1 t with an annual average of 805 t. This fluctuation, partially due to the migratory nature of the species, could be also attributed to the fleet activities that sometimes changed at the mercy of the operators. The analysis of the virtual population of bluefish in the Gulf of Gabes showed that, in 2002, the stock that had just recovered rightly after an excessive fishing in 1996–1997 was again subject to a fishing effort that passed its capacity (E=0.71; E>0.5). The biomass (B) estimated to be ~2178.9 t only tolerated the extraction of 713.4 t (more or less one-third of B). However, the three fleets in use removed 1029.1 t with a yield per recruit (Y/R) of 70.5 g. As a result of this over-fishing, the actual stock of bluefish in the Gulf of Gabes was characterized by individuals having a mean total length of 17.88 cm, a size which is much lower than the one at first sexual maturity (23.5 cm). The turnover (D/B) being of 75.23%, it did not allow the reconstitution of the stock. The total removals (~1639 t) due to both natural mortality (M=0.28) and fishing mortality (F=0.675) had to be compensated especially by individual growth (1534.2 t; 93.6%) because of the low weight of the recruits.

Mangroves as Fish Habitat

2015 ◽  
Keyword(s):  
Growth Rates ◽  
Fish Habitat ◽  
Individual Growth ◽  
Baja California Sur ◽  
Bivalve Species ◽  
Anthropogenic Pressures ◽  
La Paz ◽  
Frequency Distributions ◽  
Mass Increment ◽  
Secondary Productivity

<em>Abstract</em>.—To measure secondary productivity of mangrove systems, we estimated the abundance (individuals/m<sup>2</sup>) and mass increment (g/month) of the two bivalve species: the black ark <em>Anadara tuberculosa </em>and palmate oyster <em>Saccostrea palmula</em>. Mass increments were based on individual growth rates derived from length-frequency distributions analyses. Samples were collected at three mangrove estuaries in a sand barrier at Ensenada de La Paz from August 2007 to July 2009. The average abundance was 1.27 individuals/m<sup>2</sup> for black ark and 510 individuals/m<sup>2</sup> for palmate oysters. Estimated growth rates were 3.67 g/month for black ark and 0.18 g/month for palmate oysters. The average secondary productivity of the black ark was 4.51 g•m<sup>-2</sup>•month<sup>-1</sup> and peaked during the spring, while for the palmate oyster <em>Saccostrea palmula </em>it was 97.9 g•m<sup>-2</sup>•month<sup>-1</sup>, with peak productivity recorded during the summer. The findings of this investigation constitute a necessary element for establishing a baseline to evaluate the consequences of the various natural and anthropogenic pressures that the mangrove systems of El Mogote of La Paz Bay, Baja California Sur, Mexico.

Muskellunge Management: Fifty Years of Cooperation Among Anglers, Scientists, and Fisheries Biologists

2017 ◽  
Keyword(s):  
Growth Models ◽  
Adult Population ◽  
Open Water ◽  
Maximum Size ◽  
Population Characteristics ◽  
Residual Effects ◽  
Fish Length ◽  
Frequency Distributions ◽  
Minnesota Lakes ◽  
Spawning Periods

<em>Abstract</em>.—A population assessment of Muskellunge <em>Esox masquinongy </em>in two connected north-central Minnesota lakes allowed evaluation of angler data when assessing various population metrics, including the residual effects of historical stocking efforts, as a nonlocal strain had been introduced into the native population during the 1970s. In 2012, the Minnesota Department of Natural Resources sampled and marked Muskellunge using trap nets during the prespawn and spawning periods and electrofishing during the postspawn period, while anglers collected data from fish caught during the 2012 open-water season. Anglers released all fish after collecting a scale for genetic analysis. Microsatellite DNA genotypes were used to differentiate individuals, thus identifying recaptures, and to estimate ancestry derived from the stocked strain. Anglers reported catching 16% of individuals marked by biologists. Of Muskellunge reported by anglers, 78% were from the lake where they were initially captured while 22% were reported in the lake opposite their initial capture. Postspawn movements suggested that more individuals migrated from the lake characterized as having preferred spawning and nursery habitat to the lake characterized as having preferred summer habitat and prey. The age- and length-frequency distributions of fish captured by anglers and trap nets were similar, while electrofishing sampled younger and smaller fish, likely because it occurred postspawn when many adults had moved off shore. The best estimate of adult population size was produced by a model incorporating fish length as a covariate. Density was estimated at 0.70 adults per ha or 1.92 adults per littoral ha. Higher percentages of nonlocal ancestry were associated with smaller maximum size potential (<em>L<sub></em>∞</sub> ) in von Bertalanffy growth models. Our study described key population characteristics for a Muskellunge population while demonstrating that anglers could reliably collect several specific types of data that supplement data collected by management agencies.

The association of socioeconomic status with quality of life in cancer patients over a 6-month period using individual growth models

2019 ◽  
Vol 27 (9) ◽  
pp. 3347-3355 ◽  
Author(s):  
Julia Roick ◽  
Helge Danker ◽  
Anette Kersting ◽  
Arne Dietrich ◽  
Andreas Dietz ◽  
...  
Keyword(s):  
Quality Of Life ◽  
Socioeconomic Status ◽  
Cancer Patients ◽  
Growth Models ◽  
Individual Growth

Assessment of Unexploited Resources

1973 ◽  
Vol 30 (12) ◽  
pp. 2010-2016
Author(s):  
G. Saetersdal
Keyword(s):  
Stomach Content ◽  
Sources Of Information ◽  
Indirect Methods ◽  
Fish Biology ◽  
Acoustic Surveys ◽  
Ecological Relations

For a sound development of fisheries on the world’s remaining unused resources an evaluation of the potentials is needed, both to encourage interest and to provide guidance for timely management. The type of information required is not limited to stock potentials but should include main features of fish biology, behavior, catchability, size, quality, etc.The possible methods and sources of information are of two kinds: indirect and direct. Indirect methods make use of information on the oceanography and basic productivity of sea areas and of ecological relations. Examples are mapping of upwelling areas, charting of observations of basic productivity, and stomach content studies.Direct methods base themselves on quantitative observations of any stage of the resource itself, thus including egg, larval, and postlarval surveys, exploratory fishing, acoustic surveys, aerial scouting, and observations from vessels engaged in other primary tasks. The advantages and limitations of these various methods and the conditions for their successful use are discussed and compared.

Estimating deep web data source size by capture–recapture method

2009 ◽  
Vol 13 (1) ◽  
pp. 70-95 ◽  
Author(s):  
Jianguo Lu ◽  
Dingding Li
Keyword(s):  
Source Size ◽  
Deep Web ◽  
Web Data ◽  
Capture Recapture ◽  
Data Source
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