Stock assessment on fishery‐dependent data: Effect of data quality and parametrisation for a red snapper fishery

2021 ◽  
Author(s):  
Morgana Tagliarolo ◽  
Jason Cope ◽  
Fabian Blanchard
Keyword(s):  
Data Quality ◽  
Stock Assessment ◽  
Red Snapper ◽  
Dependent Data

scholarly journals Improvement on small-scale tuna fisheries data quality through the application of e-logbook system

2021 ◽  
Vol 869 (1) ◽  
pp. 012020
Author(s):  
S A Raup ◽  
S Patmiarsih ◽  
R D Juniar ◽  
B Setyadji
Keyword(s):  
Data Quality ◽  
Promising Result ◽  
Low Cost ◽  
Vital Role ◽  
Dependent Data ◽  
Small Scale ◽  
Insufficient Data ◽  
General Data ◽  
Tuna Fisheries ◽  
Temporal Coverage

Abstract Tuna and tuna-like fisheries play a vital role in Indonesian livelihood, especially in the archipelagic waters. However, despite the importance, the concern in general data collection activities for tuna, i.e., limited, with incomplete scientific knowledge and insufficient data has hampered the assessment. The purpose of this study was to analyse on how fisheries-dependent data system could transform the data quality. E-logbook has the best attribute for reaching the goals, especially for small-scale tuna fisheries. Characterised by low cost and vast spatial and temporal coverage, it is convinced on why the program should be expanded and monitored carefully. Analysis on fisheries indicators showed a promising result, especially for filling the gap which could not be covered by research.

The use of marine reserves in evaluating the dive fishery for the warty sea cucumber (Parastichopus parvimensis) in California, U.S.A.

2001 ◽  
Vol 58 (9) ◽  
pp. 1773-1781 ◽  
Author(s):  
Stephen C Schroeter ◽  
Daniel C Reed ◽  
David J Kushner ◽  
James A Estes ◽  
David S Ono
Keyword(s):  
Stock Assessment ◽  
Marine Reserves ◽  
Dependent Data ◽  
Fishing Mortality ◽  
Catch Per Unit Effort ◽  
Before And After ◽  
The Status ◽  
Long Term Monitoring ◽  
Term Monitoring

Management of sustainable fisheries depends upon reliable estimates of stock assessment. Assessment of many stocks is based entirely on fishery-dependent data (e.g., catch per unit effort), which can be problematic. Here we use fishery-independent data on stock size, collected within and outside of no-take reserves before and after the onset of fishing, to evaluate the status of the dive fishery for warty sea cucumbers, Parastichopus parvimensis, in southern California. Long-term monitoring data showed that abundance decreased throughout the Channel Islands within 3–6 years after the onset of fishing. No significant changes in the abundance of P. parvimensis were observed at the two non-fished reserve sites, although densities tended to increase following onset of the fishery. Before–after, control–impact (BACI) analyses of seven fished and two non-fished sites implicated fishing mortality as the cause of 33–83% stock declines. In sharp contrast, stock assessment based on CPUE data showed no declines and a significant increase at one island. To date, most discussion on marine reserves has focused on the protection and enhancement of exploited populations. Our study demonstrates the critically important, but often overlooked, role that marine reserves can play in providing reliable information on stock assessment.

How fisher behavior can bias stock assessment: insights from an agent-based modeling approach

2020 ◽  
Vol 77 (11) ◽  
pp. 1794-1809
Author(s):  
Steven Saul ◽  
Elizabeth N. Brooks ◽  
David Die
Keyword(s):  
Stock Assessment ◽  
Fish Population ◽  
Dependent Data ◽  
Commercial Fishing ◽  
Fishing Activity ◽  
Agent Based ◽  
Dependent Observations ◽  
Sampling Protocols ◽  
Fishing Fleets ◽  
Fisher Behavior

During stock assessment, fishery-dependent observations are often used to develop indices of abundance or biomass from catch per unit of effort (CPUE) and contribute catch at size or age information. However, fisher behavior, rather than scientific sampling protocols, determines the spatial and temporal locations of fishery-dependent observations. As a result, trends from fishery-dependent data may be a function of fishing activity rather than fish population changes. This study evaluates whether data collected from commercial fishing fleets in the Gulf of Mexico are representative of trends in fish population size. A coupled bioeconomic agent-based model was developed to generate simulated fishery data, which were used to populate an age-structured stock assessment. Comparison of stock assessment results with simulated fish population dynamics showed that management advice from assessment models based on fishery-dependent data could be biased. Assessment of fish with small home ranges harvested by fishing fleets that frequent the same fishing grounds could cause overestimation of fishing mortality. Not accounting for the spatial structure of the fishers or fish can cause biased estimates of population status.

Influence of data quality and quantity from a multiyear tagging program on an integrated fish stock assessment

2013 ◽  
Vol 70 (7) ◽  
pp. 1031-1045 ◽  
Author(s):  
Philippe Eric Ziegler
Keyword(s):  
Population Dynamics ◽  
Data Collection ◽  
Data Quality ◽  
Stock Assessment ◽  
Fish Stock ◽  
Modeling Framework ◽  
Auxiliary Data ◽  
Size Classes ◽  
Stock Depletion ◽  
Fish Stock Assessment

Using a modeling framework for toothfish (Dissostichus spp.) population dynamics, fishing, and data collection, this study investigated how the bias and precision of biomass estimates from an integrated tag-based assessment are influenced by various aspects of a multiyear tagging program, particularly the effects of the size of tagged fish compared with the size of fish in the catch (tag size-overlap), numbers of tagged fish, duration of the tagging program, using catch-at-length or catch-at-age data as auxiliary data, and stock depletion levels. Biomass estimates generally improved with more and better-quality tagging data. The results showed that even when tag releases were distributed over a relatively large number of size classes, low recapture numbers collected in short tagging programs with a 100% tag size-overlap were sufficient for robust and unbiased assessments. Particularly in the early stages of the tagging program, a high tag size-overlap was imperative to maximize the likelihood of a robust assessment. Biomass estimates were largely unaffected by the stock depletion level; however, using catch-at-age compared with catch-at-length improved recruitment estimates and resulted in more conservative biomass estimates.

Retrospective stock assessment of the Emperor red snapper (Lutjanus sebae) on the Seychelles Bank between 1977 and 2006

2008 ◽  
Vol 65 (6) ◽  
pp. 889-898 ◽  
Author(s):  
E. M. Grandcourt ◽  
T. Hecht ◽  
A. J. Booth ◽  
J. Robinson
Keyword(s):  
Sexual Maturity ◽  
Stock Assessment ◽  
Growth Potential ◽  
Red Snapper ◽  
Sustainable Harvest ◽  
Slow Growth Rate ◽  
Mean Size ◽  
Size At Age ◽  
Yield Per Recruit ◽  
Immature Fish

Abstract Grandcourt, E. M., Hecht, T., Booth, A. J., and Robinson, J. 2008. Retrospective stock assessment of the Emperor red snapper (Lutjanus sebae) on the Seychelles Bank between 1977 and 2006. – ICES Journal of Marine Science, 65: 889–898. The stock status of the Emperor red snapper (Lutjanus sebae) on the Seychelles Bank was determined between 1977 and 2006 using models of yield-per-recruit (YPR) and spawner-biomass-per-recruit (SBR). Demographic parameters were derived from size frequency and size-at-age data from validated annuli in sagittal otoliths. The long lifespan (tmax = 28 years), slow growth rate (k = 0.14), empirically estimated low natural mortality rate (M = 0.12), and late age at sexual maturity (tm = 9 years for males and females combined) predisposed the L. sebae resource to overfishing. Fish became vulnerable to the gear at a mean size (Lc50 = 39.8 cm LF) and age (3.1 years) before the attainment of sexual maturity at 62 cm LF. Consequently, there was a large proportion of immature fish in landings (51.2% on average) and the full growth potential for the resource might not have been realized. For most years, the fishing mortality rates and SBR approximated the limit reference point F30%. The potential for recruitment-overfishing was identified for some years (1990 and 2004), and the dramatic increase in recent yields is further evidence that management of this fishery requires urgent attention. Previous length-based assessments probably overestimated sustainable harvest rates, which should be between 6.7% and 7.2% of the SBR.

A Review of Failure Handling Mechanisms for Data Quality Measures

2012 ◽  
Author(s):  
Nurul A. Emran ◽  
Noraswaliza Abdullah ◽  
Nuzaimah Mustafa
Keyword(s):  
Data Quality ◽  
Quality Measures ◽  
Failure Handling

The Role of Technological Change in the Long-run Global Economy Forecasting

2013 ◽  
pp. 97-116 ◽  
Author(s):  
A. Apokin
Keyword(s):  
Technological Change ◽  
Data Quality ◽  
Long Range ◽  
Global Economy ◽  
World Economy ◽  
Qualitative Approaches ◽  
Long Run ◽  
The World ◽  
National Economies

The author compares several quantitative and qualitative approaches to forecasting to find appropriate methods to incorporate technological change in long-range forecasts of the world economy. A?number of long-run forecasts (with horizons over 10 years) for the world economy and national economies is reviewed to outline advantages and drawbacks for different ways to account for technological change. Various approaches based on their sensitivity to data quality and robustness to model misspecifications are compared and recommendations are offered on the choice of appropriate technique in long-run forecasts of the world economy in the presence of technological change.

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