A history and evaluation of catch‐only stock assessment models

2021 ◽  
Author(s):  
Daniel Ovando ◽  
Christopher M. Free ◽  
Olaf P. Jensen ◽  
Ray Hilborn
Keyword(s):  
Stock Assessment

FIRST RECORD AND INITIAL HYDROACOUSTIC STOCK ASSESSMENT OF POLLAN COREGONUS AUTUMNALIS PALLAS IN LOUGH ALLEN, IRELAND

2010 ◽  
Vol 110 (1) ◽  
pp. 69-74 ◽  
Author(s):  
Andrew J. Harrison ◽  
Fiona L. Kelly ◽  
Robert S. Rosell ◽  
Trevor W.S. Champ ◽  
Lynda Connor ◽  
...  
Keyword(s):  
Stock Assessment ◽  
First Record

THE STOCK ASSESSMENT OF OTOLITHES RUBER IN NORTH-WEST ARABIAN GULF

2010 ◽  
Vol 23 (0) ◽  
pp. 1-14
Author(s):  
Amina A. Hashim ◽  
A.R.M.Mohamed ◽  
Amjad K. Resen
Keyword(s):  
Stock Assessment ◽  
Arabian Gulf ◽  
North West ◽  
Otolithes Ruber

Fecundity and Gonado-somatic Index of Trichiurus lepturus (Linnaeus, 1758) Along the Zamboanga del Norte Coast

2018 ◽  
Vol 6 (7) ◽  
pp. 120
Author(s):  
Ma. Dulce C. Guillena
Keyword(s):  
Sex Ratio ◽  
Stock Assessment ◽  
Chi Square ◽  
Moon Phases ◽  
Ovary Weight ◽  
Moment Coefficient ◽  
Trichiurus Lepturus ◽  
Significant Difference ◽  
The Relationship ◽  
Somatic Index

Gonado-somatic index and fecundity are tools for measuring the sexual maturity and ability of animals to reproduce.  This study investigates the reproduction of Trichiurus lepturus. Specifically, this aimed to determine the sex ratio, the GSI, the relationship between fecundity and total length, fecundity and total weight, fecundity and ovary weight. The Descriptive Method of research was used.  Percentage and chi-square was utilized in determining the percentage of occurrence and sex ratio respectively.   Pearson r Product Moment Coefficient of Correlation was used to determine the relationships of the parameters. The study revealed that females outnumbered males and the sex ratio for different month showed significant difference.  Spawning season was observed to occur in November and December as revealed in its GSI values and it synchronized with the full and new moon phases.  Fecundity is positively correlated with body weight, body size, and ovary weight where ovary weight is observed to be the best index for fecundity.  The results of this study could be used further for formal stock assessment of cutlassfish fishery.

Recount pirarucu: a method for evaluating the quality of the pirarucu counts.

2011 ◽  
Vol 7 (1) ◽  
pp. 29-40 ◽  
Author(s):  
Lorena Candice de Araújo Andrade ◽  
Ellen Silvia Ramos Amaral ◽  
Nataluzo Balbino da Silva ◽  
Helder Lima de Queiroz
Keyword(s):  
Management System ◽  
Main Parameter ◽  
Stock Assessment ◽  
Counting Method ◽  
Technical Staff

The pirarucu counting method is a simplified stock assessment that has been used as the main parameter for establishing the annual fishing quotas in the management system of the Mamirauá and Amanã Reserves. In spite of the method’s directness, considering the recent expansion of managed fisheries, we cannot confirm that the counters thoroughly obey the original methodology. There is a concern of a technical nature, as the results of the counts directly influence the fishing quotas, and the lack of technical supervision or the inadequate application of the method are factors that can compromise the management system as a whole. This study aims to assess the counts that took place in six fishing environments of the Jarauá Sector, Mamirauá Reserve, and in four fishing environments of the area of the Pantaleão Fishing Agreement Complex, Amanã Reserve. We verified the consistency of the information resulting from the count, presented to the technical staff. To do this, we conducted recounts of juvenile and adult pirarucus in the same environments. In the Jarauá Sector we found significant differences in the counting results from Samaumerinha do Tucuxi and Curuçá do Centro. In Comprido do Maciel we found differences regarding the number of counted areas. In the sampled environments from the Pantaleão region we did not find significant differences between the counts. The results highlight the importance of creating assessment mechanisms for the counts, for the purpose of preventing possible alterations in the results that might influence the fishing quotas without a biological reason for justifying such quotas.

Chesapeake Bay Stock Assessment: Who are they, and Where are they?

1992 ◽  
Vol 26 (12) ◽  
pp. 2705-2709 ◽  
Author(s):  
H. M. Austin
Keyword(s):  
Chesapeake Bay ◽  
Stock Assessment ◽  
Human Consumption ◽  
Population Fluctuations ◽  
Important Species ◽  
Fisheries Resources ◽  
Environmentally Sensitive ◽  
Climate Scale ◽  
Resource And Environment

The Chesapeake Bay, while a significant habitat for fisheries resources, is in actuality an aquatic “bedroom community”, as many of the economically important species are seasonally transient. The pressure on these resources due to their demand for human consumption and recreation, proximity to extensive industrial activity along the shores, and climate scale environmental fluctuations has resulted in stock declines by most important species. Our inability to separate natural population fluctuations from those of anthropogenic origin complicates management efforts. The only way to make these separations, and subsequent informed management decisions is by supporting long-term stock assessment programs (monitoring) in the Bay which allow us to examine trends, cycles and stochastic processes between resource and environment. These programs need to monitor both recruitment and fishing mortality rates of the economically important species, and to identify and monitor the environmentally sensitive “canary” species.

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

scholarly journals How to Evaluate Downed Fine Woody Debris Including Logging Residues?

Forests ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 881
Author(s):  
Nathalie Korboulewsky ◽  
Isabelle Bilger ◽  
Abdelwahab Bessaad
Keyword(s):  
Wood Density ◽  
Stock Assessment ◽  
Woody Debris ◽  
Diameter Class ◽  
Density Measurements ◽  
Fine Woody Debris ◽  
Forest Inventories ◽  
Test Zone ◽  
Fixed Area ◽  
Volume Estimates

Volume or biomass estimates of downed woody debris are crucial for numerous applications such as forest carbon stock assessment, biodiversity assessments, and more recently for environmental evaluations of biofuel harvesting practices. Both fixed-area sampling (FAS) and line-intersect sampling (LIS) are used in forest inventories and ecological studies because they are unbiased and accurate methods. Nevertheless, most studies and inventories take into account only coarse woody debris (CWD, >10 cm in diameter), although fine woody debris (FWD) can account for a large part of the total downed biomass. We compared the LIS and FAS methods for FWD volume or biomass estimates and evaluated the influence of diameter and wood density measurements, plot number and size. We used a Test Zone (a defined surface area where a complete inventory was carried out, in addition to FAS and LIS), a Pilot Stand (a forest stand where both LIS and FAS methods were applied) and results from 10 field inventories in deciduous temperate forest stands with various conditions and amounts of FWD. Both methods, FAS and LIS, provided accurate (in trueness and precision) volume estimates, but LIS proved to be the more efficient. Diameter measurement was the main source of error: using the mean diameter, even by diameter class, led to an error for volume estimates of around 35%. On the contrary, wood density measurements can be simplified without much influence on the accuracy of biomass estimates (use of mean density by diameter class). We show that the length and number of transects greatly influences the estimates, and that it is better to apply more, shorter transects than fewer, longer ones. Finally, we determined the optimal methodology and propose a simplification of some measurements to obtain the best time-precision trade-off for FWD inventories at the stand level.

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.

Biology and stock assessment of the Sparids, Acanthopagrus bifasciatus and Argyrops spinifer (Forsskål, 1775), in the Southern Arabian Gulf

2004 ◽  
Vol 69 (1) ◽  
pp. 7-20 ◽  
Author(s):  
E.M Grandcourt ◽  
T.Z Al Abdessalaam ◽  
F Francis ◽  
A.T Al Shamsi
Keyword(s):  
Stock Assessment ◽  
Arabian Gulf
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