GLORIA

GEOMAR Library Ocean Research Information Access

X

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Online Resource
    Online Resource
    Hierarchical Bayesian estimation of recruitment parameters and reference points for Pacific rockfishes (Sebastes spp.) under alternative assumptions about the stock–recruit function
    Canadian Science Publishing ; 2010
    In:  Canadian Journal of Fisheries and Aquatic Sciences Vol. 67, No. 10 ( 2010-10), p. 1611-1634
    Details
    In: Canadian Journal of Fisheries and Aquatic Sciences, Canadian Science Publishing, Vol. 67, No. 10 ( 2010-10), p. 1611-1634
    Abstract: Hierarchical Bayesian meta-analysis can be a useful method for improving estimation of key parameters for harvested fish populations. In hierarchical models, data from multiple populations are used simultaneously to obtain estimates of parameters for individual populations and characterize the variability among populations. Many populations of Pacific rockfishes ( Sebastes spp.) have declined off the US West Coast since the 1980s, and there is also concern for their conservation in Canada. We develop a hierarchical Bayesian meta-analysis to improve estimates of stock–recruit parameters, characterize management-related parameters (e.g., optimal harvest rate), and address uncertainties in the structural form of the stock–recruit function for Pacific rockfishes. We estimate steepness and optimal harvest rates for 14 populations of Pacific rockfishes under alternative assumptions about the underlying stock–recruit function (Beverton–Holt and Ricker). We provide a posterior predictive distribution of steepness for rockfishes that can be used as a prior in future assessments for similar populations. We also evaluate whether F 40% is an appropriate proxy for F MSY for Pacific rockfishes and show that uncertainty in the natural mortality rate can have a significant effect on management advice derived from meta-analyses of stock–recruit data.
    Type of Medium: Online Resource
    ISSN: 0706-652X , 1205-7533
    URL: Article
    DOI: 10.1139/F10-077
    Language: English
    Publisher: Canadian Science Publishing
    Publication Date: 2010
    detail.hit.zdb_id: 7966-2
    detail.hit.zdb_id: 1473089-3
    SSG: 21,3
    SSG: 12
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 2
    Online Resource
    Online Resource
    A new likelihood for simultaneously estimating von Bertalanffy growth parameters, gear selectivity, and natural and fishing mortality
    Canadian Science Publishing ; 2005
    In:  Canadian Journal of Fisheries and Aquatic Sciences Vol. 62, No. 1 ( 2005-01-01), p. 215-223
    Details
    In: Canadian Journal of Fisheries and Aquatic Sciences, Canadian Science Publishing, Vol. 62, No. 1 ( 2005-01-01), p. 215-223
    Abstract: Gear selectivity and the cumulative effects of size-selective fishing produce bias in the length-at-age samples used to estimate the von Bertalanffy growth parameters. In fished populations, fast-growing young fish and slow-growing old fish are overrepresented in sizeage samples. To account for such effects, we treated size-at-age observations as multinomial samples, with expected catches in each sizeage category dependent on growth parameters, growth variation, size selectivity, abundance at age, and the history of exploitation. Using simulated data sets, estimated growth parameters using the multinomial likelihood were unbiased when fishing mortality was not too high and the shape of the vulnerability function was correct. In contrast, estimated growth parameters using a least squares approach overestimated the metabolic growth coefficient (K) and underestimated mean asymptotic length (L ∞ ). Models that do not explicitly account for the effects of fishing and size selectivity underestimated L ∞ and overestimated K. We estimate growth parameters for northern pikeminnow (Ptychocheilus oregonensis) as an example of the method and document a stunted "pigmy" population with an L ∞ of 175-mm fork length, attributing its small size to effects of high density and (or) a short growing season.
    Type of Medium: Online Resource
    ISSN: 0706-652X , 1205-7533
    URL: Article
    DOI: 10.1139/f04-189
    Language: English
    Publisher: Canadian Science Publishing
    Publication Date: 2005
    detail.hit.zdb_id: 7966-2
    detail.hit.zdb_id: 1473089-3
    SSG: 21,3
    SSG: 12
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 3
    Online Resource
    Online Resource
    An age-structured model with leading management parameters, incorporating age-specific selectivity and maturity
    Canadian Science Publishing ; 2008
    In:  Canadian Journal of Fisheries and Aquatic Sciences Vol. 65, No. 2 ( 2008-02-01), p. 286-296
    Details
    In: Canadian Journal of Fisheries and Aquatic Sciences, Canadian Science Publishing, Vol. 65, No. 2 ( 2008-02-01), p. 286-296
    Abstract: Previous authors have shown analytically that the optimal equilibrium harvest rate (U MSY ) for an iteroparous fish stock is a function of the slope of the stock-recruitment curve at low stock size (α) and that U MSY can therefore be considered a direct measure of stock productivity. As such, it can be used as a leading parameter in stock assessment models and directly estimated using Bayesian or similar techniques. Here we present an alternative method for deriving α from U MSY that incorporates age-specific selectivity and fecundity, avoiding assumptions of knife-edged recruitment and maturity. We present an age-structured model with two fisheries reference points (U MSY and maximum sustainable yield, MSY) as its leading parameters. We show equilibrium properties of the model, chiefly in terms of its ability to show relationships between life history traits, density dependence, and U MSY . We also demonstrate a simple Bayesian estimation routine to illustrate estimation of U MSY and MSY directly from data. We compare our results to those from a structurally identical model with leading biological parameters. Using models with leading management parameters can improve communicability of results to managers.
    Type of Medium: Online Resource
    ISSN: 0706-652X , 1205-7533
    URL: Article
    DOI: 10.1139/f07-156
    Language: English
    Publisher: Canadian Science Publishing
    Publication Date: 2008
    detail.hit.zdb_id: 7966-2
    detail.hit.zdb_id: 1473089-3
    SSG: 21,3
    SSG: 12
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 4
    Online Resource
    Online Resource
    A historical review of selectivity approaches and retrospective patterns in the Pacific halibut stock assessment
    Elsevier BV ; 2014
    In:  Fisheries Research Vol. 158 ( 2014-10), p. 40-49
    Details
    In: Fisheries Research, Elsevier BV, Vol. 158 ( 2014-10), p. 40-49
    Type of Medium: Online Resource
    ISSN: 0165-7836
    URL: Article
    DOI: 10.1016/j.fishres.2013.09.012
    Language: English
    Publisher: Elsevier BV
    Publication Date: 2014
    detail.hit.zdb_id: 406532-3
    detail.hit.zdb_id: 1497860-X
    SSG: 21,3
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 5
    Online Resource
    Online Resource
    A stochastic approach to stock reduction analysis
    Canadian Science Publishing ; 2006
    In:  Canadian Journal of Fisheries and Aquatic Sciences Vol. 63, No. 1 ( 2006-01-01), p. 212-223
    Details
    In: Canadian Journal of Fisheries and Aquatic Sciences, Canadian Science Publishing, Vol. 63, No. 1 ( 2006-01-01), p. 212-223
    Abstract: Stock reduction analysis (SRA) can complement more detailed assessment methods by using long-term historical catches to estimate recruitment rates needed to have produced those catches, yet still end up with stock sizes near those estimated by the detailed methods. A longer historical perspective can also add information to the estimation of reference points such as unfished biomass (B 0 ) or target biomass (B MSY ). Deterministic SRA models provide a single stock size trajectory that is vanishingly unlikely to have actually occurred, while stochastic SRA attempts to provide probability distributions for stock size over time under alternative hypotheses about unfished recruitment rates and about variability around assumed stockrecruitment relationships. These distributions can be generated with age-structured population models by doing large numbers of Monte Carlo simulation trials and retaining those sample trials for which the stock would not have been driven to extinction by historical catches. By resampling from these trials using likelihood weights (sampling importance resampling method), it is possible to move into fully Bayesian, statespace assessment modeling through a series of straightforward steps and to provide understandable visualization of how much the data help to reduce uncertainty about historical fishing impacts and stock status.
    Type of Medium: Online Resource
    ISSN: 0706-652X , 1205-7533
    URL: Article
    DOI: 10.1139/f05-213
    Language: English
    Publisher: Canadian Science Publishing
    Publication Date: 2006
    detail.hit.zdb_id: 7966-2
    detail.hit.zdb_id: 1473089-3
    SSG: 21,3
    SSG: 12
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 6
    Online Resource
    Online Resource
    Retrospective bioeconomic analysis of Fraser River sockeye salmon fishery management
    Elsevier BV ; 2009
    In:  Fisheries Research Vol. 97, No. 1-2 ( 2009-4), p. 32-41
    Details
    In: Fisheries Research, Elsevier BV, Vol. 97, No. 1-2 ( 2009-4), p. 32-41
    Type of Medium: Online Resource
    ISSN: 0165-7836
    URL: Article
    DOI: 10.1016/j.fishres.2008.12.018
    Language: English
    Publisher: Elsevier BV
    Publication Date: 2009
    detail.hit.zdb_id: 406532-3
    detail.hit.zdb_id: 1497860-X
    SSG: 21,3
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 7
    Online Resource
    Online Resource
    A Lagrangian approach to model movement of migratory species
    Canadian Science Publishing ; 2018
    In:  Canadian Journal of Fisheries and Aquatic Sciences Vol. 75, No. 8 ( 2018-08), p. 1203-1214
    Details
    In: Canadian Journal of Fisheries and Aquatic Sciences, Canadian Science Publishing, Vol. 75, No. 8 ( 2018-08), p. 1203-1214
    Abstract: We introduce a Lagrangian movement model that can be used to characterize cyclic migrations of iteroparous fish populations. We demonstrate how movement parameters can be estimated using conventionally available catch-at-age data and provide a description of the potential bias that may arise from model misspecification, data aggregation, and nonstandardized sampling effort. The model can be extended to incorporate covariates representing biological and environmental forces that alter the distribution and migration range of exploited populations. We expect that this movement model will be a useful tool to model fish migration, to illustrate how fisheries dynamics are affected by fish migration, and to be used as an operating model in closed loop simulations to test the robustness of management frameworks to spatial structure and connectivity.
    Type of Medium: Online Resource
    ISSN: 0706-652X , 1205-7533
    URL: Article
    DOI: 10.1139/cjfas-2017-0093
    Language: English
    Publisher: Canadian Science Publishing
    Publication Date: 2018
    detail.hit.zdb_id: 7966-2
    detail.hit.zdb_id: 1473089-3
    SSG: 21,3
    SSG: 12
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 8
    Online Resource
    Online Resource
    Catch-and-release and size limit regulations for blue, white, and striped marlin: the role of postrelease survival in effective policy design
    Canadian Science Publishing ; 2008
    In:  Canadian Journal of Fisheries and Aquatic Sciences Vol. 65, No. 5 ( 2008-05-01), p. 975-988
    Details
    In: Canadian Journal of Fisheries and Aquatic Sciences, Canadian Science Publishing, Vol. 65, No. 5 ( 2008-05-01), p. 975-988
    Abstract: Catch-and-release fishing as a management and conservation tool for billfish (family Istiophoridae) is practiced in many recreational fisheries, and mandatory release of billfish has been implemented for some commercial fisheries. Inherent in these approaches is the observation that survival of released fish is greater than those that are landed. Recent studies using pop-up satellite tags have begun to quantify postrelease survival rates for billfish, yet the efficacy of management measures that require some or all billfish to be released have not been evaluated. Using an age- and size-structured population model that accounts for individual variability in growth, we simulated the effects of postrelease mortality on yield, risk of recruitment overfishing, efficiency (i.e., ratio of harvest to postrelease mortality), and probability of catching trophy-sized individuals for three marlin species. Regulations such as size limits, catch-and-release, and mandatory release are likely to provide some benefit to billfish populations, but our results show that the effectiveness of these strategies is reduced when release survival is less than 100%. The management approaches most likely to benefit billfish populations are ones that focus on maximizing postrelease survival in the recreational fishery and minimize the billfish catch in commercial fisheries.
    Type of Medium: Online Resource
    ISSN: 0706-652X , 1205-7533
    URL: Article
    DOI: 10.1139/f08-020
    Language: English
    Publisher: Canadian Science Publishing
    Publication Date: 2008
    detail.hit.zdb_id: 7966-2
    detail.hit.zdb_id: 1473089-3
    SSG: 21,3
    SSG: 12
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 9
    Online Resource
    Online Resource
    Reconstructing ecosystem dynamics in the central Pacific Ocean, 19521998. II. A preliminary assessment of the trophic impacts of fishing and effects on tuna dynamics
    Canadian Science Publishing ; 2002
    In:  Canadian Journal of Fisheries and Aquatic Sciences Vol. 59, No. 11 ( 2002-11-01), p. 1736-1747
    Details
    In: Canadian Journal of Fisheries and Aquatic Sciences, Canadian Science Publishing, Vol. 59, No. 11 ( 2002-11-01), p. 1736-1747
    Abstract: Pelagic fisheries in the Pacific Ocean target both large (Thunnus spp.) and small tunas (juveniles of Thunnus spp; Katsuwonus pelamis) but also take billfishes (Xiphias gladius, Makaira spp., Tetrapturus spp., Istiophorus platypterus) and sharks (Prionace glauca, Alopias superciliosus, Isurus oxyrinchus, Carcharhinus longimanus, Galeocerdo cuvieri) as bycatch. We developed a multispecies model using the Ecopath with Ecosim software that incorporated time-series estimates of biomass, fishing mortality, and bycatch rates (19521998) to evaluate the relative contributions of fishing and trophic impacts on tuna dynamics in the central Pacific (0°N to 40°N and 130°E to 150°W). The Ecosim model reproduced the observed trends in abundance indices and biomass estimates for most large tunas and billfishes. A decline in predation mortality owing to depletion of large predators was greatest for small yellowfin tuna and could possibly account for apparent increases in biomass. For other tunas, however, predicted changes in predation mortality rates were small (small bigeye) or were overwhelmed by much larger increases in fishing mortality (skipjack and small albacore). Limited evidence of trophic impacts associated with declining apex predator abundance likely results from the difficulties of applying detailed trophic models to open ocean systems in which ecological and fishery data uncertainties are large.
    Type of Medium: Online Resource
    ISSN: 0706-652X , 1205-7533
    URL: Article
    DOI: 10.1139/f02-138
    Language: English
    Publisher: Canadian Science Publishing
    Publication Date: 2002
    detail.hit.zdb_id: 7966-2
    detail.hit.zdb_id: 1473089-3
    SSG: 21,3
    SSG: 12
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 10
    Online Resource
    Online Resource
    Parameterizing age-structured models from a fisheries management perspective
    Canadian Science Publishing ; 2008
    In:  Canadian Journal of Fisheries and Aquatic Sciences Vol. 65, No. 8 ( 2008-08), p. 1586-1600
    Details
    In: Canadian Journal of Fisheries and Aquatic Sciences, Canadian Science Publishing, Vol. 65, No. 8 ( 2008-08), p. 1586-1600
    Abstract: Age-structured models are widely used in fisheries stock assessments and contain two very important parameters that determine the rate and amount of harvest that can be safely taken: the compensation rate in juvenile survival (κ) and the unfished biomass (B o ). These two parameters are often confounded. It is common for relative abundance indices to lack contrast, and the use of informative priors, or fixing at least one of these parameters, is necessary to develop management advice. Providing management advice proceeds by transforming estimates of biological variables such as B o and κ into management variables such as the maximum sustainable yield (C*) and the fishing mortality rate that would achieve this yield (F*). There is no analytical solution for the transformation of B o , κ to C*, or F* for age-structured models with commonly used stock–recruitment functions and therefore must be done numerically. The opposite transition, however, does have an analytical solution for both the Beverton–Holt and Ricker recruitment models with partial selectivities for all age classes. Use of these analytical solutions allows for age-structured assessment models to be directly parameterized in terms of the management variables C* and F*. The effects of informative priors on C* and F* on the results of the assessment model are completely transparent to management.
    Type of Medium: Online Resource
    ISSN: 0706-652X , 1205-7533
    URL: Article
    DOI: 10.1139/F08-055
    Language: English
    Publisher: Canadian Science Publishing
    Publication Date: 2008
    detail.hit.zdb_id: 7966-2
    detail.hit.zdb_id: 1473089-3
    SSG: 21,3
    SSG: 12
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...