Estimating exploitation rates of migrating yellowtail flounder (Limanda ferruginea) using multistate mark–recapture methods incorporating tag loss and variable reporting rates

2009 ◽  
Vol 66 (8) ◽  
pp. 1245-1255 ◽  
Author(s):  
Laura Cowen ◽  
Stephen John Walsh ◽  
Carl James Schwarz ◽  
Noel Cadigan ◽  
Joanne Morgan
Keyword(s):  
Mortality Rates ◽  
Assessment Model ◽  
Natural Mortality ◽  
Mark Recapture ◽  
Yellowtail Flounder ◽  
Limanda Ferruginea ◽  
Tag Loss ◽  
Model Migration ◽  
Reporting Rates ◽  
Mortality Estimates

Multistate mark–recapture models can be used to model migration through stratification of the study area into states (location). However, the incorporation of both tag loss and reporting rates is new to the multistate paradigm. We develop a migration model for fish that incorporates tag loss and reporting rates but has as its primary purpose the modelling of exploitation and natural mortality rates. This model is applied to a 2000–2004 yellowtail flounder ( Limanda ferruginea ) tagging study on the Grand Bank of Newfoundland, Canada. We found that exploitation rates varied over both location and years, ranging from 0.000 to 0.047. Migration into the centre of the Grand Bank (state 2) was three times higher than migration out. The estimate of the instantaneous annual natural mortality rate was 0.256, which is equivalent to an annual survival rate of 0.880. We describe how these mortality estimates will be quite valuable in specifying an assessment model for this stock.

scholarly journals SPAM (Sex-Structured Pandalus Assessment Model): a stock assessment model for Pandalus stocks

2012 ◽  
Vol 69 (4) ◽  
pp. 770-783 ◽  
Author(s):  
Hilaire Drouineau ◽  
Louise Savard ◽  
Mathieu Desgagnés ◽  
Daniel Duplisea
Keyword(s):  
Stock Assessment ◽  
Sex Change ◽  
Assessment Model ◽  
Natural Mortality ◽  
The Novel ◽  
Fishing Mortality ◽  
Novel Structure ◽  
Shrimp Fisheries ◽  
Analytical Tools ◽  
Mortality Estimates

Despite the economic importance of Pandalus shrimp fisheries, few analytical tools have been developed to assess their stocks, and traditional stock assessment models are not appropriate because of biological specificities of Pandalus species. In this context, we propose SPAM (Sex-Structured Pandalus Assessment Model), a model dedicated to protandric hermaphrodite pandalids stock assessment. Pandalids are difficult to assess because the cues affecting sex change, size at recruitment, and mortality variability are not well understood or characterized. The novel structure of the model makes it possible to adequately describe variability in natural mortality by stage and in time, as well as variability in size at sex change and recruitment. The model provides traditional stock assessment outputs, such as fishing mortality estimates and numbers of individuals, and provides in addition yearly natural mortality estimates. The model is applied to the exploited shrimp stock of Pandalus borealis in Sept-Îles (Québec, Canada) as an illustrative example of the utility of the approach.

scholarly journals Simulation testing the robustness of a multiregion, tag-integrated assessment model that exhibits natal homing and estimates natural mortality and reporting rate

2017 ◽  
Vol 74 (11) ◽  
pp. 1930-1949 ◽  
Author(s):  
Matthew T. Vincent ◽  
Travis O. Brenden ◽  
James R. Bence
Keyword(s):  
Reporting Rate ◽  
Integrated Assessment Model ◽  
Assessment Model ◽  
Model Complexity ◽  
Natural Mortality ◽  
Movement Rates ◽  
Natal Homing ◽  
Accuracy And Precision ◽  
Simulation Testing ◽  
Reporting Rates

The influence of model complexity on integrated tagging and catch-at-age analysis (ITCAAN) parameter estimation is poorly understood for populations exhibiting natal homing. We investigated ITCAAN performance under varying levels of movement, degree of similarity in population productivities, data quality, spatial complexity in parameterization, and whether natural mortality and (or) reporting rates were fixed at actual values, estimated, or misspecified. Dynamics of four populations with natal homing that intermixed during periods of harvest were simulated based on Lake Erie walleye (Sander vitreus). Our results suggest, when high-quality tagging data are available, ITCAAN models are able to simultaneously estimate movement rates, natural mortality, and tag reporting rates, though accuracy and precision of model estimates will decrease with greater model complexity and fewer tags released. Additionally, ITCAAN models may have difficulty estimating individual population abundances under certain movement rates when population productivities are vastly different. ITCAAN models that estimate natural mortality and reporting rates may perform best with similar sized populations and when data are available to assist the estimation of reporting rates.

scholarly journals Demonstration of a spatially explicit, tag-integrated stock assessment model with application to three interconnected stocks of yellowtail flounder off of New England

2014 ◽  
Vol 72 (1) ◽  
pp. 164-177 ◽  
Author(s):  
Daniel R. Goethel ◽  
Christopher M. Legault ◽  
Steven X. Cadrin
Keyword(s):  
New England ◽  
Integrated Assessment ◽  
Stock Assessment ◽  
Assessment Model ◽  
Spatially Explicit ◽  
Closed Population ◽  
Yellowtail Flounder ◽  
Limanda Ferruginea ◽  
Stock Assessments ◽  
Source Sink

Abstract Ignoring population structure and connectivity in stock assessment models can introduce bias into important management metrics. Tag-integrated assessment models can account for spatially explicit population dynamics by modelling multiple population components, each with unique demographics, and estimating movement among them. A tagging submodel is included to calculate predicted tag recaptures, and observed tagging data are incorporated in the objective function to inform estimates of movement and mortality. We describe the tag-integrated assessment framework and demonstrate its use through an application to three stocks of yellowtail flounder (Limanda ferruginea) off New England. Movement among the three yellowtail flounder stocks has been proposed as a potential source of uncertainty in the closed population assessments of each. A tagging study was conducted during 2003–2006 with over 45 000 tagged fish released in the region, and the tagging data were included in the tag-integrated model. Results indicated that movement among stocks was low, estimates of stock size and fishing mortality were similar to those from conventional stock assessments, and incorporating stock connectivity did not resolve residual patterns. Despite low movement estimates, new interpretations of regional stock dynamics may have important implications for regional fisheries management given the source-sink nature of movement estimates.

A Bayesian state–space mark–recapture model to estimate exploitation rates in mixed-stock fisheries

2006 ◽  
Vol 63 (2) ◽  
pp. 321-334 ◽  
Author(s):  
Catherine G.J Michielsens ◽  
Murdoch K McAllister ◽  
Sakari Kuikka ◽  
Tapani Pakarinen ◽  
Lars Karlsson ◽  
...  
Keyword(s):  
State Space ◽  
Expert Knowledge ◽  
Mortality Rates ◽  
Fishing Effort ◽  
Model Parameters ◽  
Fishing Mortality ◽  
Mark Recapture ◽  
Observation Process ◽  
Mixed Stock ◽  
Reporting Rates

A Bayesian state–space mark–recapture model is developed to estimate the exploitation rates of fish stocks caught in mixed-stock fisheries. Expert knowledge and published results on biological parameters, reporting rates of tags and other key parameters, are incorporated into the mark–recapture analysis through elaborations in model structure and the use of informative prior probability distributions for model parameters. Information on related stocks is incorporated through the use of hierarchical structures and parameters that represent differences between the stock in question and related stocks. Fishing mortality rates are modelled using fishing effort data as covariates. A state–space formulation is adopted to account for uncertainties in system dynamics and the observation process. The methodology is applied to wild Atlantic salmon (Salmo salar) stocks from rivers located in the northeastern Baltic Sea that are exploited by a sequence of mixed- and single-stock fisheries. Estimated fishing mortality rates for wild salmon are influenced by prior knowledge about tag reporting rates and salmon biology and, to a limited extent, by prior assumptions about exploitation rates.

scholarly journals Estimating natural and fishing mortality and tag reporting rate of southern rock lobster (Jasus edwardsii) from a multiyear tagging model

2001 ◽  
Vol 58 (12) ◽  
pp. 2490-2501 ◽  
Author(s):  
S D Frusher ◽  
J M Hoenig
Keyword(s):  
Mortality Rates ◽  
Fishing Effort ◽  
Reporting Rate ◽  
Standard Errors ◽  
Natural Mortality ◽  
Fishing Mortality ◽  
Rock Lobster ◽  
Relative Standard ◽  
Jasus Edwardsii ◽  
Mortality Estimates

Fishing and natural mortality rates and tag reporting rate for rock lobsters (Jasus edwardsii) in northwest Tasmania, Australia, were estimated using multiyear tagging models. These estimates are necessary for assessment of the resource. Several models were examined that had either two or three tagging events each year, and either combined sexes or kept sexes separate. The model that best described the dynamics of the fishery utilized three tagging events within a year. The year was divided into discrete periods and, within each year, fishing effort and duration of period were used to apportion fishing and natural mortalities, respectively, to the periods. The separation of fishing mortalities by sex was not found to improve the models. Although high (1.0–1.2·year–1), the instantaneous fishing mortality estimates were comparable to estimates obtained from other methods and the relative standard errors were low. Reporting rate estimates were also precise and indicated a lack of participation by the fishing industry. Estimates of natural mortality were low (0.00–0.02·year–1) but imprecise.

scholarly journals A state-space stock assessment model for northern cod, including under-reported catches and variable natural mortality rates

2016 ◽  
Vol 73 (2) ◽  
pp. 296-308 ◽  
Author(s):  
Noel G. Cadigan
Keyword(s):  
State Space ◽  
Gadus Morhua ◽  
Stock Assessment ◽  
Mortality Rates ◽  
Assessment Model ◽  
Data Sources ◽  
Natural Mortality ◽  
Similar Data ◽  
Subjective Data ◽  
Northern Cod

A state-space assessment model for the northern cod (Gadus morhua) stock off southern Labrador and eastern Newfoundland is developed here. The model utilizes information from offshore trawl surveys, inshore acoustic surveys, fishery catch age compositions, partial fishery landings, and tagging. This is done using an approach that avoids the use of subjective data-weighting. Estimates of fishing mortality rates (F) are usually conditional on assumptions about natural mortality rates (M) in stock assessment models. However, by integrating much of the information on northern cod, it is possible to estimate F and M separately. It is also possible to estimate a change in the offshore survey catchability by including inshore acoustic biomass estimates. The proposed model also accounts for biased total catch statistics, which is a common problem in stock assessments. The main goal of the model is to provide realistic projections of the impacts of various levels of future fishery catches on the recovery of this stock. The projections incorporate uncertainty about M and catch. This is vital information for successful future fisheries. The model has been developed for the specific data sources available for northern cod, but it could be adapted to other stocks with similar data sources.

scholarly journals Should all fish in mark–recapture experiments be double-tagged? Lessons learned from tagging coastal cod (Gadus morhua)

2011 ◽  
Vol 68 (3) ◽  
pp. 603-610 ◽  
Author(s):  
Björn Björnsson ◽  
Hjalti Karlsson ◽  
Vilhjálmur Thorsteinsson ◽  
Jón Solmundsson
Keyword(s):  
Detection Rate ◽  
Gadus Morhua ◽  
Reporting Rate ◽  
Lessons Learned ◽  
Marine Science ◽  
Mark Recapture ◽  
Tag Loss ◽  
Electronic Tag ◽  
Reporting Rates

Abstract Björnsson, B., Karlsson, H., Thorsteinsson, V., and Solmundsson, J. 2011. Should all fish in mark–recapture experiments be double-tagged? Lessons learned from tagging coastal cod (Gadus morhua). – ICES Journal of Marine Science, 68: . Cod (Gadus morhua) were tagged outside and inside “herds” formed by anthropogenic feeding in an Icelandic fjord. Recapture rates were twice as high for fish double-tagged with one surgically implanted electronic tag and one anchor tag (46.6 and 62.2%) than with fish tagged with only a single anchor tag (20.0 and 29.2%) outside and inside the herds, respectively. The two main reasons for the differences observed in recapture rates were higher detection and reporting rates for the double-tagged fish. In cage experiments, 8% of the fish receiving implanted tags died during the first 2 d after tagging. For double-tagged fish, tag loss was ∼10% for both tag types. About 80% of the tags were returned by fishers and 20% by fish processors. The tag detection rate by fishers was estimated at ∼45 and ∼80% for single- and double-tagged fish, and the reporting rate at ∼74 and ∼100% for single- and double-tagged fish, respectively. It is proposed for future tagging studies to double-tag all fish routinely, placing one tag dorsally and one ventrally, to enhance the detection rate and to account for tag loss.

Estimation of tag reporting rates in agestructured multicomponent fisheries where one component has observers

1999 ◽  
Vol 56 (7) ◽  
pp. 1255-1265 ◽  
Author(s):  
William S Hearn ◽  
Thomas Polacheck ◽  
Kenneth H Pollock ◽  
Wade Whitelaw
Keyword(s):  
Maximum Likelihood ◽  
Maximum Likelihood Estimators ◽  
Bluefin Tuna ◽  
Mortality Rates ◽  
Reporting Rate ◽  
Natural Mortality ◽  
Integrated Likelihood ◽  
Age Dependent ◽  
Southern Bluefin Tuna ◽  
Reporting Rates

For many tagging experiments, it is vital that fishers find and report all tags to scientists. If not, the tag reporting rate needs to be estimated so that fishing and natural mortality rates can be estimated. One way to estimate this rate is to have one fishery component (e.g., with observers) report every tag found from all fish that it catches. If the numbers of fish caught by all fishery components are also known and the tagged fish are mixed with the population (or subpopulation) being harvested, then one can estimate the reporting rate of underreporting fishery components. This procedure can fail if data are pooled over ages. We obtain maximum likelihood estimators for the reporting rate for each age and (or) each fishery component. We show how to estimate reporting rates if mixing of tagged and untagged fish occurs with some delay. We also obtain overall age-dependent reporting rates, which combine reporting rates from all components of the fishery. Our likelihood is part of an integrated likelihood that allows estimation of age-dependent fishing and natural mortalities in addition to the reporting rates. Our procedures are illustrated with some southern bluefin tuna (Thunnus maccoyii) tagging data.

A combined telemetry – tag return approach to estimate fishing and natural mortality rates of an estuarine fish

2009 ◽  
Vol 66 (8) ◽  
pp. 1230-1244 ◽  
Author(s):  
Nathan M. Bacheler ◽  
Jeffrey A. Buckel ◽  
Joseph E. Hightower ◽  
Lee M. Paramore ◽  
Kenneth H. Pollock
Keyword(s):  
Mortality Rate ◽  
Seasonal Pattern ◽  
Mortality Rates ◽  
Sciaenops Ocellatus ◽  
State Agency ◽  
Estuarine Fish ◽  
Joint Analysis ◽  
Natural Mortality ◽  
Combined Model ◽  
Reporting Rates

A joint analysis of tag return and telemetry data should improve estimates of mortality rates for exploited fishes; however, the combined approach has thus far only been tested in terrestrial systems. We tagged subadult red drum ( Sciaenops ocellatus ) with conventional tags and ultrasonic transmitters over 3 years in coastal North Carolina, USA, to test the efficacy of the combined telemetry – tag return approach. There was a strong seasonal pattern to monthly fishing mortality rate (F) estimates from both conventional and telemetry tags; highest F values occurred in fall months and lowest levels occurred during winter. Although monthly F values were similar in pattern and magnitude between conventional tagging and telemetry, information on F in the combined model came primarily from conventional tags. The estimated natural mortality rate (M) in the combined model was low (estimated annual rate ± standard error: 0.04 ± 0.04) and was based primarily upon the telemetry approach. Using high-reward tagging, we estimated different tag reporting rates for state agency and university tagging programs. The combined telemetry – tag return approach can be an effective approach for estimating F and M as long as several key assumptions of the model are met.

Testing the performance of a spatially explicit tag-integrated stock assessment model of yellowtail flounder (Limanda ferruginea) through simulation analysis

2015 ◽  
Vol 72 (4) ◽  
pp. 582-601 ◽  
Author(s):  
Daniel R. Goethel ◽  
Christopher M. Legault ◽  
Steven X. Cadrin
Keyword(s):  
Stock Assessment ◽  
Population Models ◽  
Assessment Model ◽  
Spatially Explicit ◽  
Parameter Estimates ◽  
Integrated Models ◽  
Closed Population ◽  
Yellowtail Flounder ◽  
Limanda Ferruginea ◽  
Wide Range

In any stock assessment application, the implicit assumptions regarding spatial population structure must be carefully evaluated. Tag-integrated models offer a promising approach for incorporating spatial structure and movement patterns in stock assessments, but the complexity of the framework makes implementation challenging and the appraisal of performance difficult. A flounder-like fishery was simulated to emulate the metapopulation dynamics of the three yellowtail flounder (Limanda ferruginea) stocks off New England, and the robustness of spatially explicit tag-integrated models were compared with closed population assessments. Different movement parametrizations and data uncertainty scenarios were simulated, while the ability of the tag-integrated model to estimate reporting rate and time-varying movement were also evaluated. Results indicated that the tag-integrated framework was robust for the simulated fishery across a wide range of connectivity levels and that tag reporting rates were accurately estimated. Closed population models also demonstrated limited error. Therefore, spatially explicit approaches may not always be warranted even when regional connectivity is occurring, but tag-integrated models can provide improved parameter estimates when reliable tagging data are available. Tag-integrated models also serve as valuable tools for informing spatially explicit operating models, which can then be used to evaluate the assumptions and performance of closed population models.

Sign in / Sign up

Export Citation Format

Share Document