scholarly journals Genetic identification of blue rockfish (Sebastes mystinus) and deacon rockfish (S. diaconus) to enable life history analyses for stock assessment

2020 ◽  
Vol 118 (1) ◽  
pp. 37-50
Author(s):  
Joseph J. Bizzarro ◽  
Elizabeth A. Gilbert-Horvath ◽  
E. J. Dick ◽  
Aaron M. Berger ◽  
Katherine T. Schmidt ◽  
...  
Keyword(s):  
Life History ◽  
Stock Assessment ◽  
Genetic Identification ◽  
Sebastes Mystinus

Review of the life history, fisheries, and stock assessment for small tunas in the Atlantic Ocean

2021 ◽  
Author(s):  
Flávia Lucena-Frédou ◽  
Bruno Mourato ◽  
Thierry Frédou ◽  
Pedro G. Lino ◽  
Rubén Muñoz-Lechuga ◽  
...  
Keyword(s):  
Life History ◽  
Atlantic Ocean ◽  
Stock Assessment

Rapid changes in life-history characteristics of a long-lived temperate reef fish

2007 ◽  
Vol 58 (12) ◽  
pp. 1096 ◽  
Author(s):  
Philippe E. Ziegler ◽  
Jeremy M. Lyle ◽  
Malcolm Haddon ◽  
Graeme P. Ewing
Keyword(s):  
Life History ◽  
Reef Fish ◽  
Stock Assessment ◽  
Contributing Factors ◽  
Young Males ◽  
Temperate Reef ◽  
Life History Characteristics ◽  
Rapid Changes ◽  
Temperate Reef Fish ◽  
Underlying Mechanisms

Banded morwong, Cheilodactylus spectabilis, a long-lived sedentary temperate reef fish, has undergone rapid changes in its growth and maturity characteristics along the east coast of Tasmania, Australia. Over a period of 10 years, growth of young males and females has consistently accelerated, such that in 2005, 3-year-old fish were up to 40 mm or 13% longer compared with 1996, and age at 50% maturity for females had declined from 4 to 3 years. The magnitude and speed of the observed changes were unexpected given the species’ longevity (maximum age of over 95 years). The underlying mechanisms for the changes remain unclear but density-dependent responses to changes in population size and age composition, possibly mediated through reduced competition for shelter and intra-specific interactions, may have been contributing factors. Increasing sea surface temperatures over part of the period of change does not appear to have been a major driver and a genetic response to fishing seems unlikely. Notwithstanding any uncertainty, C. spectabilis populations have become more productive in recent years, challenging the general approach towards stock assessment where life-history characteristics are assumed to remain stable across contrasting levels of stock abundance and environmental conditions.

scholarly journals A method for calculating a meta-analytical prior for the natural mortality rate using multiple life history correlates

2014 ◽  
Vol 72 (1) ◽  
pp. 62-69 ◽  
Author(s):  
Owen S. Hamel
Keyword(s):  
Life History ◽  
Mortality Rate ◽  
Stock Assessment ◽  
Meta Analysis ◽  
Assessment Model ◽  
Natural Mortality ◽  
Uncertainty Interval ◽  
Free Data ◽  
Stock Assessments ◽  
Measure Of Uncertainty

Abstract The natural mortality rate M is an important parameter for understanding population dynamics, and is extraordinarily difficult to estimate for many fish species. The uncertainty associated with M translates into increased uncertainty in fishery stock assessments. Estimation of M within a stock assessment model is complicated by its confounding with other life history and fishery parameters which are also uncertain, some of which are typically estimated within the model. Ageing error and variation in growth, which may not be fully modelled, can also affect estimation of M, as can various assumptions, including the form of the stock–recruitment function (e.g. Beverton–Holt, Ricker) and the level of compensation (or steepness), which may be fixed (or limited by a prior) in the model. To avoid these difficulties, stock assessors often assume point estimates for M derived from meta-analytical relationships between M and more easily measured life history characteristics, such as growth rate or longevity. However, these relationships depend on estimates of M for a great number of species, and those estimates are also subject to errors and biases (as are, to a lesser extent, the other life history parameters). Therefore, at the very least, some measure of uncertainty in M should be calculated and used for evaluating uncertainty in stock assessments and management strategy evaluations. Given error-free data on M and the covariate(s) for a meta-analysis, prediction intervals would provide the appropriate measure of uncertainty in M. In contrast, if the relationship between the covariate(s) and M is exact and the only error is in the estimates of M used for the meta-analysis, confidence intervals would appropriate. Using multiple published meta-analyses of M’s relationship with various life history correlates, and beginning with the uncertainty interval calculations, I develop a method for creating combined priors for M for use in stock assessment.

Assessing the sensitivity of data-limited methods (DLMs) to the estimation of life-history parameters from length–frequency data

2018 ◽  
Vol 75 (10) ◽  
pp. 1563-1572 ◽  
Author(s):  
Ming Sun ◽  
Chongliang Zhang ◽  
Yong Chen ◽  
Binduo Xu ◽  
Ying Xue ◽  
...  
Keyword(s):  
Life History ◽  
Stock Assessment ◽  
Stock Management ◽  
Larimichthys Polyactis ◽  
Life History Parameters ◽  
Control Rules ◽  
Strategy Evaluation ◽  
Management Procedures ◽  
Spawning Potential Ratio ◽  
Harvest Control Rules

Data-limited methods (DLMs) in stock assessment may provide potential critical information for data-limited stock management. However, the sensitivity of those methods to life-history parameters is largely unknown, resulting in extra uncertainty and consequent risks. In the present study, we designed six parallel workflows (WFs) to incorporate classic and state-of-the-art methods of estimating life-history parameters and examined their influences on the assessment of small yellow croaker (Larimichthys polyactis) in Haizhou Bay, China. The sensitivity was evaluated with three objectives: (i) the evaluation of stock status with the spawning potential ratio following different assumptions; (ii) the length-based harvest control rules derived from three management procedures; and (iii) the management performance of these harvest control rules with simulation of management strategy evaluation. The results showed considerable sensitivity regarding the three objectives to the estimations with different WFs, indicating the previous practice of credulously accepting empirical values and indiscriminately selecting references are inadvisable. We also identified the most appropriate WFs used for different purposes with limited data, aiming to provide more reliable inputs for effective fisheries management.

scholarly journals Age-based and reproductive biology of the Pacific Longnose Parrotfish Hipposcarus longiceps from Guam

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e4079 ◽  
Author(s):  
Brett M. Taylor ◽  
Eric Cruz
Keyword(s):  
Life History ◽  
Fishery Management ◽  
Stock Assessment ◽  
Fork Length ◽  
Growth Patterns ◽  
Life History Trait ◽  
Fishery Resource ◽  
Species Vulnerability ◽  
The Pacific ◽  
Improved Model

The Pacific longnose parrotfish Hipposcarus longiceps (Valenciennes 1840) represents a prime fishery resource throughout much of the tropical Pacific. In this study, we sampled the species from the Guam commercial fishery market across five consecutive years to characterize reproductive and age-based demographic information imperative for informed fishery management. Compared with other parrotfishes, this species was found to be large-bodied, but has only a moderate life span of 10 + years. Hipposcarus longiceps was confirmed as a diandric protogynous hermaphrodite with highly sex-specific growth patterns and an overall mean asymptotic length of 434 mm fork length (FL). Females were estimated to reach median maturity at 329 mm FL (2.4 years) and have a median length at female-to-male sex change of 401 mm FL. Life-history trait values derived here were used to update previous models relating life history and vulnerability to overexploitation. We found that enhancement of just one species’ trait values improved model fits considerably, which strengthens the conclusion that life-history traits are a strong determinant of species’ vulnerability in the parrotfishes. This information is an imperative complement to other data sources facilitating formal stock assessment of a key fishery target.

scholarly journals A stepwise stochastic simulation approach to estimate life history parameters for data-poor fisheries

2016 ◽  
Vol 73 (12) ◽  
pp. 1874-1884 ◽  
Author(s):  
Marc O. Nadon ◽  
Jerald S. Ault
Keyword(s):  
Life History ◽  
Stock Assessment ◽  
Probability Distributions ◽  
Size Composition ◽  
History Data ◽  
Life History Parameters ◽  
Life History Data ◽  
Novel Approach ◽  
Cost Efficient ◽  
Species Specific

Coastal fisheries are typically characterized by species-rich catch compositions and limited management resources, which typically leads to notably data-poor situations for stock assessment. Some parsimonious stock assessment approaches rely on cost-efficient size composition data, but these also require estimates of life history parameters associated with natural mortality, growth, and maturity. These parameters are unavailable for most exploited stocks. Here, we present a novel approach that uses a local estimate of maximum length and statistical relationships between key life history parameters to build multivariate probability distributions that can be used to parameterize stock assessment models in the absence of species-specific life history data. We tested this approach on three fish species for which empirical length-at-age and maturity data were available (from Hawaii and Guam) and calculated probability distributions of spawning potential ratios (SPR) at different exploitation rates. The life history parameter and SPR probability distributions generated from our data-limited analytical approach compared well with those obtained from bootstrap analyses of the empirical life history data. This work provides a useful new tool that can greatly assist fishery stock assessment scientists and managers in data-poor situations, typical of most of the world’s fisheries.

scholarly journals Ensemble models for data-poor assessment: accounting for uncertainty in life-history information

2019 ◽  
Vol 76 (4) ◽  
pp. 870-883 ◽  
Author(s):  
Merrill B Rudd ◽  
James T Thorson ◽  
Skyler R Sagarese
Keyword(s):  
Life History ◽  
Learning Algorithm ◽  
Stock Assessment ◽  
Model Averaging ◽  
Biological Information ◽  
Parameter Distribution ◽  
Life History Parameter ◽  
Multivariate Distributions ◽  
Life History Parameters ◽  
Parameter Values

Abstract Length measurements from fishery catch can be used in data-limited assessments to estimate important population parameters to guide management, but results are highly sensitive to assumptions about biological information. Ideally, local life history studies inform biological parameters. In the absence of reliable local estimates, scientists and managers face the difficult task of agreeing on fixed values for life-history parameters, often leading to additional uncertainty unquantified in the assessment or indecision defaulting to status-quo management. We propose an ensemble approach for incorporating life history uncertainty into data-limited stock assessments. We develop multivariate distributions of growth, mortality, and maturity parameter values, then use bivariate interpolation and stacking as an ensemble learning algorithm to propagate uncertainty into length-based, data-limited stock assessment models. Simulation testing demonstrated that stacking across life history parameter values leads to improved interval coverage over simple model averaging or assuming the parameter distribution means when the true life-history parameter values are unknown. We then applied the stacking approach for a U.S. Caribbean stock where the Scientific and Statistical Committee did not accept the assessment due to uncertainty in life history parameters. Stacking can better characterize uncertainty in stock status whenever life-history parameters are unknown but likely parameter distributions are available.

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