Coral Reef Habitats and Fish Connectivity : Implications for coastal management and fishery

Coral reefs have one of the highest levels of biodiversity of all ecosystems in the world and are important for both human livelihood and food security throughout many tropical countries. However, due to increased anthropogenic pressure on marine ecosystems, especially during the last couple of deca...

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Main Author: Jörgensen, Tove Lund
Format: Doctoral Thesis
Language:English
Published: Stockholms universitet, Institutionen för ekologi, miljö och botanik 2016
Subjects:
Online Access:http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-125595
http://nbn-resolving.de/urn:isbn:978-91-7649-337-3
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spelling ndltd-UPSALLA1-oai-DiVA.org-su-1255952017-02-21T05:15:01ZCoral Reef Habitats and Fish Connectivity : Implications for coastal management and fisheryengJörgensen, Tove LundStockholms universitet, Institutionen för ekologi, miljö och botanikStockholm : Department of Ecology, Environment and Plant Sciences, Stockholm University2016anthropogenic disturbancecoral reef habitatfish communitycoastal ecosystemsconservation managementspatial ecologyseascape perspectiveholistic approachCoral reefs have one of the highest levels of biodiversity of all ecosystems in the world and are important for both human livelihood and food security throughout many tropical countries. However, due to increased anthropogenic pressure on marine ecosystems, especially during the last couple of decades, coral reefs have become critically over-fished, and many reefs are now in a degraded state and are facing additional future threats due to further over-exploitation, chemical pollution, sedimentation, and effects of climate change. The main aim of this PhD thesis was to understand effects of anthropogenic disturbances on tropical coastal ecosystems and fish connectivity for coastal management purposes. Therefore, linkages between anthropogenic disturbance and corals were investigated (Paper I), as well as interactions between coral reef habitat and associated fish assemblage (Paper II). Furthermore, connectivity between coral reefs and other tropical coastal ecosystems was explored (Paper III), as well as fish migration to reproduction sites (Paper IV), and evaluations of spatial ecology methods (Paper V). The result showed that coral reefs that are already exposed to disturbances, such as freshwater and nutrient run-offs, may be more sensitive to climate change, in terms of increased sea surface temperatures (Paper I). In addition, there were also clear linkages between coral reef quality, in terms of coral coverage, and fish assemblages, which displayed high spatial variability and suggesting patchy recovery after the 1997/1998 bleaching and subsequent coral mass mortality event (Paper II). This highlights the importance of understanding effects of disturbances on corals, especially in terms of synergistic effects between increased water temperatures and other coastal stressors such as decreased salinity and increased nutrients; and the indirect effects of habitat degradation on the fish community. Linkages between fish and different coastal habitats were further explored. The results showed that coral reefs were strongly connected with mangrove and seagrass beds, through ontogenetic migration of fish (Paper III). Migrations to spawning sites of groupers were related to lunar activities when thousands of fish gather for reproduction purposes during new moon, which increases the risk of over-exploitation (Paper IV). The results emphasises the importance of protecting key areas such as nursing grounds and reproduction sites. Furthermore, acoustic telemetry has become an increasingly common method in studies of fish movement, and the results showed that efficiency of acoustic arrays may increase depending on deployment strategies and habitat characteristics (Paper V). In conclusion, the results from this PhD thesis emphasises the importance of protecting coral reef habitats, as well as identifying related susceptible tropical coastal areas, such as nursing grounds and reproduction sites. Indeed, a better scientific understanding of coral reef ecology and indirect and direct effects on fish assemblages are needed for efficient and accurate coastal management decisions. <p>At the time of the doctoral defense, the following paper was unpublished and had a status as follows: Paper 5: Manuscript.</p>Doctoral thesis, comprehensive summaryinfo:eu-repo/semantics/doctoralThesistexthttp://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-125595urn:isbn:978-91-7649-337-3application/pdfinfo:eu-repo/semantics/openAccess
collection NDLTD
language English
format Doctoral Thesis
sources NDLTD
topic anthropogenic disturbance
coral reef habitat
fish community
coastal ecosystems
conservation management
spatial ecology
seascape perspective
holistic approach
spellingShingle anthropogenic disturbance
coral reef habitat
fish community
coastal ecosystems
conservation management
spatial ecology
seascape perspective
holistic approach
Jörgensen, Tove Lund
Coral Reef Habitats and Fish Connectivity : Implications for coastal management and fishery
description Coral reefs have one of the highest levels of biodiversity of all ecosystems in the world and are important for both human livelihood and food security throughout many tropical countries. However, due to increased anthropogenic pressure on marine ecosystems, especially during the last couple of decades, coral reefs have become critically over-fished, and many reefs are now in a degraded state and are facing additional future threats due to further over-exploitation, chemical pollution, sedimentation, and effects of climate change. The main aim of this PhD thesis was to understand effects of anthropogenic disturbances on tropical coastal ecosystems and fish connectivity for coastal management purposes. Therefore, linkages between anthropogenic disturbance and corals were investigated (Paper I), as well as interactions between coral reef habitat and associated fish assemblage (Paper II). Furthermore, connectivity between coral reefs and other tropical coastal ecosystems was explored (Paper III), as well as fish migration to reproduction sites (Paper IV), and evaluations of spatial ecology methods (Paper V). The result showed that coral reefs that are already exposed to disturbances, such as freshwater and nutrient run-offs, may be more sensitive to climate change, in terms of increased sea surface temperatures (Paper I). In addition, there were also clear linkages between coral reef quality, in terms of coral coverage, and fish assemblages, which displayed high spatial variability and suggesting patchy recovery after the 1997/1998 bleaching and subsequent coral mass mortality event (Paper II). This highlights the importance of understanding effects of disturbances on corals, especially in terms of synergistic effects between increased water temperatures and other coastal stressors such as decreased salinity and increased nutrients; and the indirect effects of habitat degradation on the fish community. Linkages between fish and different coastal habitats were further explored. The results showed that coral reefs were strongly connected with mangrove and seagrass beds, through ontogenetic migration of fish (Paper III). Migrations to spawning sites of groupers were related to lunar activities when thousands of fish gather for reproduction purposes during new moon, which increases the risk of over-exploitation (Paper IV). The results emphasises the importance of protecting key areas such as nursing grounds and reproduction sites. Furthermore, acoustic telemetry has become an increasingly common method in studies of fish movement, and the results showed that efficiency of acoustic arrays may increase depending on deployment strategies and habitat characteristics (Paper V). In conclusion, the results from this PhD thesis emphasises the importance of protecting coral reef habitats, as well as identifying related susceptible tropical coastal areas, such as nursing grounds and reproduction sites. Indeed, a better scientific understanding of coral reef ecology and indirect and direct effects on fish assemblages are needed for efficient and accurate coastal management decisions. === <p>At the time of the doctoral defense, the following paper was unpublished and had a status as follows: Paper 5: Manuscript.</p>
author Jörgensen, Tove Lund
author_facet Jörgensen, Tove Lund
author_sort Jörgensen, Tove Lund
title Coral Reef Habitats and Fish Connectivity : Implications for coastal management and fishery
title_short Coral Reef Habitats and Fish Connectivity : Implications for coastal management and fishery
title_full Coral Reef Habitats and Fish Connectivity : Implications for coastal management and fishery
title_fullStr Coral Reef Habitats and Fish Connectivity : Implications for coastal management and fishery
title_full_unstemmed Coral Reef Habitats and Fish Connectivity : Implications for coastal management and fishery
title_sort coral reef habitats and fish connectivity : implications for coastal management and fishery
publisher Stockholms universitet, Institutionen för ekologi, miljö och botanik
publishDate 2016
url http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-125595
http://nbn-resolving.de/urn:isbn:978-91-7649-337-3
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