Stock assessment and fishery management of Henicorhynchus spp., Cyclocheilichthys enoplos and Channa micropeltes in Tonle Sap Great Lake, Cambodia

2009 ◽  
Vol 35 (2) ◽  
pp. 169-174 ◽  
Author(s):  
Nguyen T. Hai Yen ◽  
Kengo Sunada ◽  
Satoru Oishi ◽  
Kou Ikejima ◽  
Tomaya Iwata
Keyword(s):  
Great Lake ◽  
Fishery Management ◽  
Stock Assessment ◽  
Tonle Sap

scholarly journals Designing tools to evaluate fishery management strategies: can the scientific community deliver?

2007 ◽  
Vol 64 (6) ◽  
pp. 1077-1084 ◽  
Author(s):  
Jon T. Schnute ◽  
Mark N. Maunder ◽  
James N. Ianelli
Keyword(s):  
Programming Languages ◽  
Scientific Community ◽  
Fishery Management ◽  
Stock Assessment ◽  
Management Strategies ◽  
Academic Disciplines ◽  
Strategy Evaluation ◽  
Management Procedures ◽  
Human Skills ◽  
Testing Management

Abstract Schnute, J. T., Maunder, M. N., and Ianelli, J. N. 2007. Designing tools to evaluate fishery management strategies: can the scientific community deliver? – ICES Journal of Marine Science, 64: 1077–1084. Techniques for quantitative fishery management have evolved rapidly during a period when computers, programming languages, and computational algorithms have also changed dramatically. Despite these advances, many stock assessment methods remain untested. A process of management strategy evaluation (MSE) could potentially rectify this problem, but it would require a framework in which to conduct systematic tests. We survey the tools currently used for stock assessments and discuss the development of new standards for testing management procedures. A successful project would depend on human skills scattered among various nations, organizations, and academic disciplines. Analogies from civil engineering illustrate the discipline and collaboration required for an effective outcome. If the world community of fishery scientists could design, build, and support such a project, it would revolutionize the theory, teaching, and practice of scientific fishery management.

New synonyms and a new subspecies of Macrogomphus Selys, 1858 (Odonata: Gomphidae) from continental south-east Asia

Zootaxa ◽  
2019 ◽  
Vol 4615 (1) ◽  
pp. 57
Author(s):  
OLEG E. KOSTERIN
Keyword(s):  
East Asia ◽  
Great Lake ◽  
Diagnostic Character ◽  
South East Asia ◽  
New Subspecies ◽  
New Synonyms ◽  
Siem Reap ◽  
Tonle Sap ◽  
Lake Tonle Sap ◽  
The Relationship

The taxa of the genus Macrogomphus Selys, 1858 occurring in continental south-east Asia are reconsidered. Macrogomphus rivularis Förster, 1914 (described from Vietnam), M. borikhanensis Fraser, 1933 (described from Laos), and M. guilinensis Chao, 1983 (described from China), are synonymised with M. albardae Selys, 1878. The relationship and conspecificity of the latter with M. parallelogramma Burmeister, 1839 are doubtful, perhaps they are bona species. Males of M. albardae (and seemingly of parallelogramma as well) are approximately trimorphic for the pale pattern of the abdominal S3–S6, being of either a ‘dashed morph’ (with small isolated anteriolateral spots and conspicuous middorsal streaks), or a ‘ringed morph (with broad anterior rings and less conspicuous middorsal streaks), or an ‘intermediate morph’. Validity of the species M. matsukii Asahina, 1986 is doubted; its holotype could be an aberrant male of M. albardae. The main diagnostic character of M. albardae, M. phalantus Lieftinck, 1935 and probably M. parallelogramma, is clarified to be the structure of the cercus inner branch. M. phalantus jayavarman subsp. nov. is described from temporarily inundated forest at the northern bank of the great Lake Tonlé Sap of Cambodia (Siem Reap Province, 1.5 km SSW of Kampong Pluk village, 13.1956° N, 103.9725° E, 3 m a.s.l.), which is ca 1,300 km north and overseas from the presumed range of M. phalantus phalantus. 

scholarly journals Non-linearity in stock–recruitment relationships of Atlantic cod: insights from a multi-model approach

2019 ◽  
Vol 77 (4) ◽  
pp. 1492-1502 ◽  
Author(s):  
Camilla Sguotti ◽  
Saskia A Otto ◽  
Xochitl Cormon ◽  
Karl M Werner ◽  
Ethan Deyle ◽  
...  
Keyword(s):  
Environmental Variables ◽  
Gadus Morhua ◽  
Fishery Management ◽  
Atlantic Cod ◽  
Stock Assessment ◽  
Fish Stock ◽  
Recovery Potential ◽  
Stock Recruitment ◽  
Model Approach ◽  
Non Parametric

Abstract The stock–recruitment relationship is the basis of any stock prediction and thus fundamental for fishery management. Traditional parametric stock–recruitment models often poorly fit empirical data, nevertheless they are still the rule in fish stock assessment procedures. We here apply a multi-model approach to predict recruitment of 20 Atlantic cod (Gadus morhua) stocks as a function of adult biomass and environmental variables. We compare the traditional Ricker model with two non-parametric approaches: (i) the stochastic cusp model from catastrophe theory and (ii) multivariate simplex projections, based on attractor state-space reconstruction. We show that the performance of each model is contingent on the historical dynamics of individual stocks, and that stocks which experienced abrupt and state-dependent dynamics are best modelled using non-parametric approaches. These dynamics are pervasive in Western stocks highlighting a geographical distinction between cod stocks, which have implications for their recovery potential. Furthermore, the addition of environmental variables always improved the models’ predictive power indicating that they should be considered in stock assessment and management routines. Using our multi-model approach, we demonstrate that we should be more flexible when modelling recruitment and tailor our approaches to the dynamical properties of each individual stock.

scholarly journals Ecological Reference Points for Atlantic Menhaden Established Using an Ecosystem Model of Intermediate Complexity

2020 ◽  
Vol 7 ◽  
Author(s):  
David Chagaris ◽  
Katie Drew ◽  
Amy Schueller ◽  
Matt Cieri ◽  
Joana Brito ◽  
...  
Keyword(s):  
Striped Bass ◽  
Fishery Management ◽  
Stock Assessment ◽  
Reference Points ◽  
Atlantic Menhaden ◽  
Assessment Model ◽  
Total Allowable Catch ◽  
Important Species ◽  
Ecosystem Impacts ◽  
Intermediate Complexity

Atlantic menhaden (Brevoortia tyrannus) are an important forage fish for many predators, and they also support the largest commercial fishery by weight on the U.S. East Coast. Menhaden management has been working toward ecological reference points (ERPs) that account for menhaden’s role in the ecosystem. The goal of this work was to develop menhaden ERPs using ecosystem models. An existing Ecopath with Ecosim model of the Northwest Atlantic Continental Shelf (NWACS) was reduced in complexity from 61 to 17 species/functional groups. The new NWACS model of intermediate complexity for ecosystems (NWACS-MICE) serves to link the dynamics of menhaden with key managed predators. Striped bass (Morone saxatilis) were determined to be most sensitive to menhaden harvest and therefore served as an indicator of ecosystem impacts. ERPs were based on the tradeoff relationship between the equilibrium biomass of striped bass and menhaden fishing mortality (F). The ERPs were defined as the menhaden F rates that maintain striped bass at their biomass target and threshold when striped bass are fished at their Ftarget, and all other modeled species were fished at status quo levels. These correspond to an ERP Ftarget of 0.19 and an ERP Fthreshold of 0.57, which are lower than the single species reference points by 30–40%, but higher than current (2017) menhaden F. The ERPs were then fed back into the age-structured stock assessment model projections to provide information on total allowable catch. The ERPs developed in this study were adopted by the Atlantic menhaden Management Board, marking a shift toward ecosystem-based fishery management for this economically and ecologically important species.

scholarly journals The economic value of environmental data: a notional insurance scheme for the European anchovy

2016 ◽  
Vol 73 (4) ◽  
pp. 1033-1041 ◽  
Author(s):  
Margarita María Rincón ◽  
John D. Mumford ◽  
Polina Levontin ◽  
Adrian W. Leach ◽  
Javier Ruiz
Keyword(s):  
Environmental Factors ◽  
Fishery Management ◽  
Stock Assessment ◽  
Life Stage ◽  
Environmental Data ◽  
Gulf Of Cadiz ◽  
Insurance Scheme ◽  
Management Regime ◽  
Insurance Cover ◽  
Gulf Of Cádiz

Abstract Anchovy population dynamics in the Gulf of Cádiz are governed by environmental processes. Sea surface temperature, intense easterly winds, and discharges from the Guadalquivir River have been identified as key factors determining early life stage mortality in this anchovy stock. We have constructed an environment-based recruitment model that simulates the abundance of juveniles under alternative parameters representing plausible biological hypotheses. We are able to evaluate how modelling environment-based recruitment can affect stock assessment and how responding to environmental information can benefit fishery management to allow greater average catch levels through the application of harvest control rules (HCRs) based on environmental conditions. While the environment-based rules generally increase allowable catch levels the variance in catch levels also increases, detracting from the improved value based only on average yield. In addition to changes in revenue, the probability of stock collapse is also reduced by using environmental factors in HCRs. To assess the value of these management systems we simulate a notional insurance scheme, which applies a value to both average yields and uncertainty. The value of the information-driven rules can be determined by comparing the relevant premiums payable for equal levels of insurance cover on revenue within each specific management regime. We demonstrate the net value of incorporating environmental factors in the management of anchovies in the Gulf of Cádiz despite the increased variability in revenue. This could be an effective method to describe outcomes for both commercial fisheries and ecosystem management policies, and as a guide to management of other species whose dynamics are predictable based on in-season observations.

scholarly journals Discard mortality rates in the Bering Sea snow crab, Chionoecetes opilio, fishery

2015 ◽  
Vol 72 (5) ◽  
pp. 1525-1529 ◽  
Author(s):  
J. Daniel Urban
Keyword(s):  
Mortality Rate ◽  
Bering Sea ◽  
Fishery Management ◽  
Stock Assessment ◽  
Mortality Rates ◽  
Snow Crab ◽  
Commercial Fishing ◽  
Chionoecetes Opilio ◽  
Discard Mortality ◽  
The Bering Sea

Abstract Fish and invertebrates that are unintentionally captured during commercial fishing operations and then released back into the ocean suffer mortality at unknown rates, introducing uncertainty into the fishery management process. Attempts have been made to quantify discard mortality rates using reflex action mortality predictors or RAMP which use the presence or absence of a suite of reflexes to predict discard mortality. This method was applied to snow crab, Chionoecetes opilio, during the 2010–2012 fisheries in the Bering Sea. Discard mortality in the fishery is currently assumed to be 50% in stock assessment models, but that rate is not based on empirical data and is widely recognized to be in need of refinement. Over 19 000 crab were evaluated using the RAMP method. The estimated discard mortality rate was 4.5% (s.d. = 0.812), significantly below the rate used in stock assessment models. Predicted discard mortality rates from the 2010 to 2012 study were strongly correlated with the air temperature at the St Paul Island airport in the Pribilof Islands. Using this relationship, the discard mortality rate from 1991 to 2011 was estimated at 4.8% (s.d. = 1.08).

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 Evaluating the role of data quality when sharing information in hierarchical multistock assessment models, with an application to Dover sole

2019 ◽  
Vol 76 (10) ◽  
pp. 1819-1835
Author(s):  
Samuel D.N. Johnson ◽  
Sean P. Cox
Keyword(s):  
Statistical Power ◽  
Fishery Management ◽  
Stock Assessment ◽  
Simulated Data ◽  
Assessment Model ◽  
Production Model ◽  
Estimation Errors ◽  
Lower Estimation ◽  
Relative Errors ◽  
Dover Sole

An emerging approach to data-limited fisheries stock assessment uses hierarchical multistock assessment models to group stocks together, sharing information from data-rich to data-poor stocks. In this paper, we simulate data-rich and data-poor fishery and survey data scenarios for a complex of Dover sole (Microstomus pacificus) stocks. Simulated data for individual stocks were used to compare estimation performance for single-stock and hierarchical multistock versions of a Schaefer production model. The single-stock and best-performing multistock models were then used in stock assessments for the real Dover sole data. Multistock models often had lower estimation errors than single-stock models when assessment data had low statistical power. Relative errors for productivity and relative biomass parameters were lower for multistock assessment model configurations. In addition, multistock models that estimated hierarchical priors for survey catchability performed the best under data-poor scenarios. We conclude that hierarchical multistock assessment models are useful for data-limited stocks and could provide a more flexible alternative to data pooling and catch-only methods; however, these models are subject to nonlinear side effects of parameter shrinkage. Therefore, we recommend testing hierarchical multistock models in closed-loop simulations before application to real fishery management systems.

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