A Mixed-Method Approach for Quantifying Illegal Fishing and Its Impact on an Endangered Fish Species
Illegal harvest is recognized as a widespread problem in natural resource management. The use of multiple methods for quantifying illegal harvest has been widely recommended yet infrequently applied. We used a mixed-method approach to evaluate the extent, character, and motivations of illegal gillne...
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ftpubmed:oai:pubmedcentral.nih.gov:4666464 2023-05-15T15:47:16+02:00 A Mixed-Method Approach for Quantifying Illegal Fishing and Its Impact on an Endangered Fish Species Free, Christopher M. Jensen, Olaf P. Mendsaikhan, Bud 2015-12-01 http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4666464/ http://www.ncbi.nlm.nih.gov/pubmed/26625154 https://doi.org/10.1371/journal.pone.0143960 en eng Public Library of Science http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4666464/ http://www.ncbi.nlm.nih.gov/pubmed/26625154 http://dx.doi.org/10.1371/journal.pone.0143960 http://creativecommons.org/licenses/by/4.0/ This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/) , which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited CC-BY Research Article Text 2015 ftpubmed https://doi.org/10.1371/journal.pone.0143960 2015-12-13T01:21:13Z Illegal harvest is recognized as a widespread problem in natural resource management. The use of multiple methods for quantifying illegal harvest has been widely recommended yet infrequently applied. We used a mixed-method approach to evaluate the extent, character, and motivations of illegal gillnet fishing in Lake Hovsgol National Park, Mongolia and its impact on the lake’s fish populations, especially that of the endangered endemic Hovsgol grayling (Thymallus nigrescens). Surveys for derelict fishing gear indicate that gillnet fishing is widespread and increasing and that fishers generally use 3–4 cm mesh gillnet. Interviews with resident herders and park rangers suggest that many residents fish for subsistence during the spring grayling spawning migration and that some residents fish commercially year-round. Interviewed herders and rangers generally agree that fish population sizes are decreasing but are divided on the causes and solutions. Biological monitoring indicates that the gillnet mesh sizes used by fishers efficiently target Hovsgol grayling. Of the five species sampled in the monitoring program, only burbot (Lota lota) showed a significant decrease in population abundance from 2009–2013. However, grayling, burbot, and roach (Rutilus rutilus) all showed significant declines in average body size, suggesting a negative fishing impact. Data-poor stock assessment methods suggest that the fishing effort equivalent to each resident family fishing 50-m of gillnet 11–15 nights per year would be sufficient to overexploit the grayling population. Results from the derelict fishing gear survey and interviews suggest that this level of effort is not implausible. Overall, we demonstrate the ability for a mixed-method approach to effectively describe an illegal fishery and suggest that these methods be used to assess illegal fishing and its impacts in other protected areas. Text Burbot Lota lota lota PubMed Central (PMC) PLOS ONE 10 12 e0143960 |
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Research Article Free, Christopher M. Jensen, Olaf P. Mendsaikhan, Bud A Mixed-Method Approach for Quantifying Illegal Fishing and Its Impact on an Endangered Fish Species |
topic_facet |
Research Article |
description |
Illegal harvest is recognized as a widespread problem in natural resource management. The use of multiple methods for quantifying illegal harvest has been widely recommended yet infrequently applied. We used a mixed-method approach to evaluate the extent, character, and motivations of illegal gillnet fishing in Lake Hovsgol National Park, Mongolia and its impact on the lake’s fish populations, especially that of the endangered endemic Hovsgol grayling (Thymallus nigrescens). Surveys for derelict fishing gear indicate that gillnet fishing is widespread and increasing and that fishers generally use 3–4 cm mesh gillnet. Interviews with resident herders and park rangers suggest that many residents fish for subsistence during the spring grayling spawning migration and that some residents fish commercially year-round. Interviewed herders and rangers generally agree that fish population sizes are decreasing but are divided on the causes and solutions. Biological monitoring indicates that the gillnet mesh sizes used by fishers efficiently target Hovsgol grayling. Of the five species sampled in the monitoring program, only burbot (Lota lota) showed a significant decrease in population abundance from 2009–2013. However, grayling, burbot, and roach (Rutilus rutilus) all showed significant declines in average body size, suggesting a negative fishing impact. Data-poor stock assessment methods suggest that the fishing effort equivalent to each resident family fishing 50-m of gillnet 11–15 nights per year would be sufficient to overexploit the grayling population. Results from the derelict fishing gear survey and interviews suggest that this level of effort is not implausible. Overall, we demonstrate the ability for a mixed-method approach to effectively describe an illegal fishery and suggest that these methods be used to assess illegal fishing and its impacts in other protected areas. |
format |
Text |
author |
Free, Christopher M. Jensen, Olaf P. Mendsaikhan, Bud |
author_facet |
Free, Christopher M. Jensen, Olaf P. Mendsaikhan, Bud |
author_sort |
Free, Christopher M. |
title |
A Mixed-Method Approach for Quantifying Illegal Fishing and Its Impact on an Endangered Fish Species |
title_short |
A Mixed-Method Approach for Quantifying Illegal Fishing and Its Impact on an Endangered Fish Species |
title_full |
A Mixed-Method Approach for Quantifying Illegal Fishing and Its Impact on an Endangered Fish Species |
title_fullStr |
A Mixed-Method Approach for Quantifying Illegal Fishing and Its Impact on an Endangered Fish Species |
title_full_unstemmed |
A Mixed-Method Approach for Quantifying Illegal Fishing and Its Impact on an Endangered Fish Species |
title_sort |
mixed-method approach for quantifying illegal fishing and its impact on an endangered fish species |
publisher |
Public Library of Science |
publishDate |
2015 |
url |
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4666464/ http://www.ncbi.nlm.nih.gov/pubmed/26625154 https://doi.org/10.1371/journal.pone.0143960 |
genre |
Burbot Lota lota lota |
genre_facet |
Burbot Lota lota lota |
op_relation |
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4666464/ http://www.ncbi.nlm.nih.gov/pubmed/26625154 http://dx.doi.org/10.1371/journal.pone.0143960 |
op_rights |
http://creativecommons.org/licenses/by/4.0/ This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/) , which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.1371/journal.pone.0143960 |
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PLOS ONE |
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10 |
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12 |
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