Assessment of the stock status of small-scale and multi-gear fisheries resources in the tropical Eastern Pacific region

Pilar Herrón*, Tobias K. Mildenberger, Juan Manuel Díaz, Matthias Wolff

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

Small-scale multi-gear fisheries contribute half of global fisheries landings but are generally data-poor, hindering their assessment and management. Aiming to overcome various existing challenges, we used two complementary length-based approaches to assess the status of three main target species in the small-scale fisheries of Eastern Pacific countries: Spotted rose snapper Lutjanus guttatus, Pacific sierra Scomberomorus sierra, and Pacific bearded Brotula clarkae, using length-frequency catch data (LFCD) from the Colombian Pacific coast. Two data sources – official governmental data and community-based monitoring from a non-government organization – were used to estimate two sets of stock indicators: one based on the derivation of growth and mortality parameters from modal progression, catch curve analysis and a yield-per-recruit model using TropFishR; and the second based on the relative contribution of fish sizes with regard to proposed reference values for healthy stocks. Growth estimates differed between data sources and exhibited large confidence intervals, indicating an overall high uncertainty underlying the LFCD revealed through a novel bootstrapped approach. Estimated values of stock indicators, exploitation rate, fishing mortality and size-proportions converged in suggesting a state of heavy to over-exploitation for the three assessed species, although differences were observed among data sources that we attribute mainly to fisheries selectivity and sampling design. In order to improve future assessments of stocks in multi-gear and data-poor contexts, estimations of fleet-specific selectivity should be used to reconstruct LFCD prior to analyses. Additionally, sampling design should be based on fishing effort distribution among gears and areas and, when feasible, fishery-independent data on stock conditions should be included.

Original languageEnglish
JournalRegional Studies in Marine Science
Volume24
Pages (from-to)311-323
ISSN2352-4855
DOIs
Publication statusPublished - 1 Nov 2018

Keywords

  • Colombia
  • Data-poor stocks
  • Fisheries management
  • Length-based indicators
  • Length-frequency data
  • TropFishR

Cite this

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title = "Assessment of the stock status of small-scale and multi-gear fisheries resources in the tropical Eastern Pacific region",
abstract = "Small-scale multi-gear fisheries contribute half of global fisheries landings but are generally data-poor, hindering their assessment and management. Aiming to overcome various existing challenges, we used two complementary length-based approaches to assess the status of three main target species in the small-scale fisheries of Eastern Pacific countries: Spotted rose snapper Lutjanus guttatus, Pacific sierra Scomberomorus sierra, and Pacific bearded Brotula clarkae, using length-frequency catch data (LFCD) from the Colombian Pacific coast. Two data sources – official governmental data and community-based monitoring from a non-government organization – were used to estimate two sets of stock indicators: one based on the derivation of growth and mortality parameters from modal progression, catch curve analysis and a yield-per-recruit model using TropFishR; and the second based on the relative contribution of fish sizes with regard to proposed reference values for healthy stocks. Growth estimates differed between data sources and exhibited large confidence intervals, indicating an overall high uncertainty underlying the LFCD revealed through a novel bootstrapped approach. Estimated values of stock indicators, exploitation rate, fishing mortality and size-proportions converged in suggesting a state of heavy to over-exploitation for the three assessed species, although differences were observed among data sources that we attribute mainly to fisheries selectivity and sampling design. In order to improve future assessments of stocks in multi-gear and data-poor contexts, estimations of fleet-specific selectivity should be used to reconstruct LFCD prior to analyses. Additionally, sampling design should be based on fishing effort distribution among gears and areas and, when feasible, fishery-independent data on stock conditions should be included.",
keywords = "Colombia, Data-poor stocks, Fisheries management, Length-based indicators, Length-frequency data, TropFishR",
author = "Pilar Herr{\'o}n and Mildenberger, {Tobias K.} and D{\'i}az, {Juan Manuel} and Matthias Wolff",
year = "2018",
month = "11",
day = "1",
doi = "10.1016/j.rsma.2018.09.008",
language = "English",
volume = "24",
pages = "311--323",
journal = "Regional Studies in Marine Science",
issn = "2352-4855",
publisher = "Elsevier",

}

Assessment of the stock status of small-scale and multi-gear fisheries resources in the tropical Eastern Pacific region. / Herrón, Pilar; Mildenberger, Tobias K.; Díaz, Juan Manuel; Wolff, Matthias.

In: Regional Studies in Marine Science, Vol. 24, 01.11.2018, p. 311-323.

Research output: Contribution to journalJournal articleResearchpeer-review

TY - JOUR

T1 - Assessment of the stock status of small-scale and multi-gear fisheries resources in the tropical Eastern Pacific region

AU - Herrón, Pilar

AU - Mildenberger, Tobias K.

AU - Díaz, Juan Manuel

AU - Wolff, Matthias

PY - 2018/11/1

Y1 - 2018/11/1

N2 - Small-scale multi-gear fisheries contribute half of global fisheries landings but are generally data-poor, hindering their assessment and management. Aiming to overcome various existing challenges, we used two complementary length-based approaches to assess the status of three main target species in the small-scale fisheries of Eastern Pacific countries: Spotted rose snapper Lutjanus guttatus, Pacific sierra Scomberomorus sierra, and Pacific bearded Brotula clarkae, using length-frequency catch data (LFCD) from the Colombian Pacific coast. Two data sources – official governmental data and community-based monitoring from a non-government organization – were used to estimate two sets of stock indicators: one based on the derivation of growth and mortality parameters from modal progression, catch curve analysis and a yield-per-recruit model using TropFishR; and the second based on the relative contribution of fish sizes with regard to proposed reference values for healthy stocks. Growth estimates differed between data sources and exhibited large confidence intervals, indicating an overall high uncertainty underlying the LFCD revealed through a novel bootstrapped approach. Estimated values of stock indicators, exploitation rate, fishing mortality and size-proportions converged in suggesting a state of heavy to over-exploitation for the three assessed species, although differences were observed among data sources that we attribute mainly to fisheries selectivity and sampling design. In order to improve future assessments of stocks in multi-gear and data-poor contexts, estimations of fleet-specific selectivity should be used to reconstruct LFCD prior to analyses. Additionally, sampling design should be based on fishing effort distribution among gears and areas and, when feasible, fishery-independent data on stock conditions should be included.

AB - Small-scale multi-gear fisheries contribute half of global fisheries landings but are generally data-poor, hindering their assessment and management. Aiming to overcome various existing challenges, we used two complementary length-based approaches to assess the status of three main target species in the small-scale fisheries of Eastern Pacific countries: Spotted rose snapper Lutjanus guttatus, Pacific sierra Scomberomorus sierra, and Pacific bearded Brotula clarkae, using length-frequency catch data (LFCD) from the Colombian Pacific coast. Two data sources – official governmental data and community-based monitoring from a non-government organization – were used to estimate two sets of stock indicators: one based on the derivation of growth and mortality parameters from modal progression, catch curve analysis and a yield-per-recruit model using TropFishR; and the second based on the relative contribution of fish sizes with regard to proposed reference values for healthy stocks. Growth estimates differed between data sources and exhibited large confidence intervals, indicating an overall high uncertainty underlying the LFCD revealed through a novel bootstrapped approach. Estimated values of stock indicators, exploitation rate, fishing mortality and size-proportions converged in suggesting a state of heavy to over-exploitation for the three assessed species, although differences were observed among data sources that we attribute mainly to fisheries selectivity and sampling design. In order to improve future assessments of stocks in multi-gear and data-poor contexts, estimations of fleet-specific selectivity should be used to reconstruct LFCD prior to analyses. Additionally, sampling design should be based on fishing effort distribution among gears and areas and, when feasible, fishery-independent data on stock conditions should be included.

KW - Colombia

KW - Data-poor stocks

KW - Fisheries management

KW - Length-based indicators

KW - Length-frequency data

KW - TropFishR

U2 - 10.1016/j.rsma.2018.09.008

DO - 10.1016/j.rsma.2018.09.008

M3 - Journal article

VL - 24

SP - 311

EP - 323

JO - Regional Studies in Marine Science

JF - Regional Studies in Marine Science

SN - 2352-4855

ER -