How many fish? Comparison of two underwater visual sampling methods for monitoring fish communities
Background Underwater visual surveys (UVSs) for monitoring fish communities are preferred over fishing surveys in certain habitats, such as rocky or coral reefs and seagrass beds and are the standard monitoring tool in many cases, especially in protected areas. However, despite their wide applicatio...
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| Format: | Article |
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PeerJ Inc.
2018-06-01
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| Online Access: | https://peerj.com/articles/5066.pdf |
| _version_ | 1797424609285373952 |
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| author | Zoi Thanopoulou Maria Sini Konstantinos Vatikiotis Christos Katsoupis Panayiotis G. Dimitrakopoulos Stelios Katsanevakis |
| author_facet | Zoi Thanopoulou Maria Sini Konstantinos Vatikiotis Christos Katsoupis Panayiotis G. Dimitrakopoulos Stelios Katsanevakis |
| author_sort | Zoi Thanopoulou |
| collection | DOAJ |
| description | Background Underwater visual surveys (UVSs) for monitoring fish communities are preferred over fishing surveys in certain habitats, such as rocky or coral reefs and seagrass beds and are the standard monitoring tool in many cases, especially in protected areas. However, despite their wide application there are potential biases, mainly due to imperfect detectability and the behavioral responses of fish to the observers. Methods The performance of two methods of UVSs were compared to test whether they give similar results in terms of fish population density, occupancy, species richness, and community composition. Distance sampling (line transects) and plot sampling (strip transects) were conducted at 31 rocky reef sites in the Aegean Sea (Greece) using SCUBA diving. Results Line transects generated significantly higher values of occupancy, species richness, and total fish density compared to strip transects. For most species, density estimates differed significantly between the two sampling methods. For secretive species and species avoiding the observers, the line transect method yielded higher estimates, as it accounted for imperfect detectability and utilized a larger survey area compared to the strip transect method. On the other hand, large-scale spatial patterns of species composition were similar for both methods. Discussion Overall, both methods presented a number of advantages and limitations, which should be considered in survey design. Line transects appear to be more suitable for surveying secretive species, while strip transects should be preferred at high fish densities and for species of high mobility. |
| first_indexed | 2024-03-09T08:04:37Z |
| format | Article |
| id | doaj.art-998b42d7b1e34abdb9dd18b06ebec1ad |
| institution | Directory Open Access Journal |
| issn | 2167-8359 |
| language | English |
| last_indexed | 2024-03-09T08:04:37Z |
| publishDate | 2018-06-01 |
| publisher | PeerJ Inc. |
| record_format | Article |
| series | PeerJ |
| spelling | doaj.art-998b42d7b1e34abdb9dd18b06ebec1ad2023-12-03T00:25:12ZengPeerJ Inc.PeerJ2167-83592018-06-016e506610.7717/peerj.5066How many fish? Comparison of two underwater visual sampling methods for monitoring fish communitiesZoi Thanopoulou0Maria Sini1Konstantinos Vatikiotis2Christos Katsoupis3Panayiotis G. Dimitrakopoulos4Stelios Katsanevakis5Department of Biology, University of Miami, Miami, FL, USADepartment of Marine Sciences, Aegean University, Mytilene, GreeceDepartment of Marine Sciences, Aegean University, Mytilene, GreeceDepartment of Marine Sciences, Aegean University, Mytilene, GreeceDepartment of the Environment, Aegean University, Mytilene, GreeceDepartment of Marine Sciences, Aegean University, Mytilene, GreeceBackground Underwater visual surveys (UVSs) for monitoring fish communities are preferred over fishing surveys in certain habitats, such as rocky or coral reefs and seagrass beds and are the standard monitoring tool in many cases, especially in protected areas. However, despite their wide application there are potential biases, mainly due to imperfect detectability and the behavioral responses of fish to the observers. Methods The performance of two methods of UVSs were compared to test whether they give similar results in terms of fish population density, occupancy, species richness, and community composition. Distance sampling (line transects) and plot sampling (strip transects) were conducted at 31 rocky reef sites in the Aegean Sea (Greece) using SCUBA diving. Results Line transects generated significantly higher values of occupancy, species richness, and total fish density compared to strip transects. For most species, density estimates differed significantly between the two sampling methods. For secretive species and species avoiding the observers, the line transect method yielded higher estimates, as it accounted for imperfect detectability and utilized a larger survey area compared to the strip transect method. On the other hand, large-scale spatial patterns of species composition were similar for both methods. Discussion Overall, both methods presented a number of advantages and limitations, which should be considered in survey design. Line transects appear to be more suitable for surveying secretive species, while strip transects should be preferred at high fish densities and for species of high mobility.https://peerj.com/articles/5066.pdfUnderwater visual censusLine transectsStrip transectsRocky reefsBiasMediterranean |
| spellingShingle | Zoi Thanopoulou Maria Sini Konstantinos Vatikiotis Christos Katsoupis Panayiotis G. Dimitrakopoulos Stelios Katsanevakis How many fish? Comparison of two underwater visual sampling methods for monitoring fish communities PeerJ Underwater visual census Line transects Strip transects Rocky reefs Bias Mediterranean |
| title | How many fish? Comparison of two underwater visual sampling methods for monitoring fish communities |
| title_full | How many fish? Comparison of two underwater visual sampling methods for monitoring fish communities |
| title_fullStr | How many fish? Comparison of two underwater visual sampling methods for monitoring fish communities |
| title_full_unstemmed | How many fish? Comparison of two underwater visual sampling methods for monitoring fish communities |
| title_short | How many fish? Comparison of two underwater visual sampling methods for monitoring fish communities |
| title_sort | how many fish comparison of two underwater visual sampling methods for monitoring fish communities |
| topic | Underwater visual census Line transects Strip transects Rocky reefs Bias Mediterranean |
| url | https://peerj.com/articles/5066.pdf |
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