Fish kills in lakes; implications to water quality and ecology

Pera, Joseph

Fish kills in lakes; implications to water quality and ecology

Pera, Joseph

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Publication Type:: Thesis
Issue Date:: 2023

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Field	Value	Language
dc.contributor.author	Pera, Joseph
dc.date.accessioned	2025-01-30T02:25:15Z
dc.date.available	2025-01-30T02:25:15Z
dc.date.issued	2023
dc.identifier.uri	http://hdl.handle.net/10453/184609
dc.description	University of Technology Sydney. Faculty of Science.	en_US.UTF-8
dc.description.abstract	Common carp Cyprinus carpio are dominant in Australian lakes. Biological control of carp using a virus would drastically reduce numbers. This thesis aimed to better understand the fate and impact of decaying fish carcasses in lakes. Mesocosm studies with carp carcasses showed a rapid drop in dissolved oxygen in all treatments to levels that would not sustain fish or invertebrates. Addition of dead carp biomass led to changes in microbial assemblage structure, shifting from typical lake bacteria, to a eutrophic signature community, including environmental copiotrophic bacteria. Following the microbial shift phytoplankton dominated all treatments and correlated positively with increasing carcass biomass as did total nitrogen, total phosphorus and chlorophyll a. Several microbes correlated with odour causing compounds geosmin and 2-Methylisoborneol (MIB) in dead carp treatments. Field monitoring revealed depth of carcasses in lakes was significant, with carcasses less likely to float from microbial bloating with increased pressure at greater depths. Large lakes had relatively lower biomass than smaller shallow lakes suggesting small lakes would be at greater risk of catastrophic water quality changes if the virus was released. Results highlight areas of concern from a virus driven carp biocontrol management program and suggests control strategies to minimise potential impacts.	en_US.UTF-8
dc.format	Thesis (PhD)
dc.language.iso	en_US	en_US.UTF-8
dc.relation	https://opus.lib.uts.edu.au/bitstream/10453/184609/1/thesis.pdf
dc.rights	info:eu-repo/semantics/openAccess
dc.rights	The author owns the copyright in this thesis including all reproduction and reuse rights for the work. The work may not be altered without the permission of the copyright owner. Attribution is essential when quoting or paraphrasing from this thesis.
dc.rights	© 2023 Joseph Pera
dc.rights	au.edu.uts.lib/cph
dc.title	Fish kills in lakes; implications to water quality and ecology	en_US.UTF-8
dc.type	Thesis
utslib.copyright.status	open_access	*

Abstract:

Common carp Cyprinus carpio are dominant in Australian lakes. Biological control of carp using a virus would drastically reduce numbers. This thesis aimed to better understand the fate and impact of decaying fish carcasses in lakes. Mesocosm studies with carp carcasses showed a rapid drop in dissolved oxygen in all treatments to levels that would not sustain fish or invertebrates. Addition of dead carp biomass led to changes in microbial assemblage structure, shifting from typical lake bacteria, to a eutrophic signature community, including environmental copiotrophic bacteria. Following the microbial shift phytoplankton dominated all treatments and correlated positively with increasing carcass biomass as did total nitrogen, total phosphorus and chlorophyll a. Several microbes correlated with odour causing compounds geosmin and 2-Methylisoborneol (MIB) in dead carp treatments. Field monitoring revealed depth of carcasses in lakes was significant, with carcasses less likely to float from microbial bloating with increased pressure at greater depths. Large lakes had relatively lower biomass than smaller shallow lakes suggesting small lakes would be at greater risk of catastrophic water quality changes if the virus was released. Results highlight areas of concern from a virus driven carp biocontrol management program and suggests control strategies to minimise potential impacts.

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http://hdl.handle.net/10453/184609