The Direct And Indirect Effects Of Marine Reserve Protection On Reef Fish Assemblages
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The Direct And Indirect Effects Of Marine Reserve Protection On Reef Fish Assemblages
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Author : Harry Allard
language : en
Publisher:
Release Date : 2020
The Direct And Indirect Effects Of Marine Reserve Protection On Reef Fish Assemblages written by Harry Allard and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2020 with categories.
Marine reserves are established to protect marine ecosystems from fishing, allowing harvested fishes to recover: these are the "direct effects" of protection. However, changes may also occur among species not typically exposed to fishing mortality, via "indirect effects" . Most marine reserve studies have focused on direct effects, and the prevalence and relative importance of indirect effects is poorly understood. Understanding both direct and indirect effects is key to understanding how fishing affects wider fish assemblages. To investigate the direct and indirect effects of marine reserve protection on reef fish assemblages I examined monitoring data from four northeastern New Zealand marine reserves. This long-term analysis also provided a wider assessment of how reef fish have changed over the last 2-4 decades in this region. Across all reserves examined, the large predatory sparid Chrysophrys auratus responded strongly to protection. This response was hypothesised to drive indirect effects on other species, as a result of increased predation, competition, or predator-induced habitat changes. Long-term changes in reef fish assemblages in New Zealand's oldest marine reserve at Leigh suggested that along with direct effects on six targeted species, snapper recovery had indirect effects on three small-bodied non-target fishes and one herbivorous fish. Comparisons across three reserves revealed that the potential indirect effects identified in Leigh were not ubiquitous. While direct effects on target species like snapper and cheilodactylid Cheilodactylus spectabilis were largely predictable, potential indirect effects were more location-specific and difficult to differentiate from the effects of environmental gradients. At an offshore island marine reserve, with a more speciose temperate-subtropical fish fauna, potential indirect effects existed for just 3 wrasses, despite dramatic direct effects of protection on snapper. There was no evidence of tropicalisation of fish assemblages at this offshore island marine reserve over the last two decades. This study demonstrated that while protected fish assemblages are distinct, this is mostly driven by the recovery of harvested species. Potential indirect effects of long-term protection were identified, but were rarely consistent across multiple reserves. Trophic links between reef fishes appear weak, and the role of indirect effects is likely overwhelmed by the direct effects of fishing.
Assessing The Direct And Indirect Effects Of Marine Reserve Protection On Temperate Reef Fish Communities
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Author : Evan Wesley Brown
language : en
Publisher:
Release Date : 2015
Assessing The Direct And Indirect Effects Of Marine Reserve Protection On Temperate Reef Fish Communities written by Evan Wesley Brown and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2015 with Fish populations categories.
Marine reserves are often effective in allowing the recovery of targeted species within their boundaries, which potentially have indirect effects on non-‐ target species. While the direct effects of protection on targeted species are fairly well understood, the indirect effects have been less well researched. In New Zealand’s oldest marine reserve at Leigh, the recovery of snapper Pagrus auratus and spiny lobster Jasus edwardsii populations has indirectly resulted in the increase of macroalgal habitats due to increased predation on sea urchins. Increased abundances of snapper and other targeted fish species may also affect other fish species via competition or predation. The main aim of this thesis was to investigate how these indirect effects, especially large-‐scale change in habitats, have affected reef fish species relative to the direct effects of protection. Reef fish abundances and sizes were estimated using habitat-‐ stratified underwater visual censuses inside and outside of the Leigh and Tawharanui marine reserves, which allowed for assessment of reef fish habitat associations. Based on these densities and the estimated extents of each habitat (from a drop-‐camera survey) the total population size of a number of key species was estimated for both reserves and surrounding coast. These estimates were then compared to historic population sizes in the Leigh Reserve that were estimated prior to habitat change. The main habitat change between 1978 and 2014 was the conversion of barrens into shallow kelp inside the Leigh reserve. In 2014 there were clear differences between reserve and fished sites at both locations, with virtually no urchin barrens and substantially more kelp habitat inside the reserves. Some species had clear habitat associations, with brown seaweed-‐associated species such as butterfish and silver drummer indirectly benefitting from increased kelp habitats in the Leigh Reserve. Overall changes in population sizes of most targeted species are most likely a direct response to protection. Some species (spotty and goatfish) were less abundant in the reserves, which may be due to increased competition or predation from snapper or other predators. In 2014 the majority of species showed a reserve effect, with greater abundance and/or average size in the reserves. However, aside from red moki, butterfish and silver drummer, which increased in abundance, and leatherjacket and banded wrasse, which showed no change, most species have declined in abundance inside the Leigh Reserve. These population declines may be a reflection of increased fishing pressure being placed on the surrounding coast, environmental change (e.g., sedimentation), or simply due to natural fluctuations in abundance. In summary, the patterns observed in this study, coupled with historic data, suggest that responses of most fish species to protection within northern New Zealand marine reserves are directly attributable to the absence of removal by fishing, with relatively few species showing indirect responses to large-‐scale habitat change or altered levels of competition or predation.
The Direct And Indirect Effects Of Predators On Coral Reef Fish Assemblages
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Author : Brian Zgliczynski
language : en
Publisher:
Release Date : 2015
The Direct And Indirect Effects Of Predators On Coral Reef Fish Assemblages written by Brian Zgliczynski and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2015 with categories.
The removal of apex predators is widely recognized to have broad ecological consequences for terrestrial and aquatic communities. In marine systems, the direct effects of fisheries exploitation include altering the community standing stock (biomass), species composition, and size-structure of the fish assemblage. Although the direct effects of fisheries exploitation are well documented, there is increasing evidence that the non-lethal effects of predation can also strongly influence the structure and function of ecological communities. In this dissertation I set out to increase our understanding of the effects of predators on coral reef fish assemblages by conducting a series of large-scale natural experiments across groups of Pacific islands spanning gradients of human population density and oceanographic productivity within four distinct geopolitical regions. My dissertation research reveals striking evidence for the effects of fisheries exploitation and oceanographic productivity on coral reef fish assemblages in three key areas. First, I found strong evidence that the effects of fisheries exploitation are not restricted to large-bodied species from higher-trophic levels but are realized throughout the entire fish assemblage and across multiple trophic groups. Importantly, I show that multiple forms of fisheries exploitation may be present on coral reefs, indicating the complex nature of coral reef fisheries. Second, I show strong evidence of biophysical coupling with gradients of oceanographic productivity and alterations in predatory fish abundance on the body condition, growth rates, maximum size, and longevity of coral reef fishes. I also observe a breakdown of natural coupling at inhabited islands, suggesting that local human impacts are capable of homogenizing life history traits of fishes even when strong environmental gradients are present. Third, I show that the trophic structure of coral reef fish assemblages are more tightly linked to changes in oceanographic productivity than to predatory fish abundance. I observed trophic channeling, a process by which different basal sources of energy entering the system can remain isolated on coral reefs forming distinct pathways up through the food web to top-level carnivores. In summary, my dissertation provides important insight into the mechanisms that structure marine communities and the direct and indirect effects of removing predators from marine ecosystems.
Austral Ark
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Author : Adam Stow
language : en
Publisher: Cambridge University Press
Release Date : 2015
Austral Ark written by Adam Stow and has been published by Cambridge University Press this book supported file pdf, txt, epub, kindle and other format this book has been release on 2015 with Nature categories.
A detailed, research-informed synthesis of the current issues facing the Australasian biota and the challenges involved in their conservation.
Marine Protected Areas
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Author : Joachim Claudet
language : en
Publisher:
Release Date : 2011-09-29
Marine Protected Areas written by Joachim Claudet and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2011-09-29 with Nature categories.
Provides regional and global perspectives on the role of Marine Protected Areas in the restoration and conservation of biodiversity.
Marine Protected Areas
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Author : Joachim Claudet
language : en
Publisher: Cambridge University Press
Release Date : 2011-09-29
Marine Protected Areas written by Joachim Claudet and has been published by Cambridge University Press this book supported file pdf, txt, epub, kindle and other format this book has been release on 2011-09-29 with Nature categories.
Human-induced environmental disturbance – through fishery activities, coastal development, tourism and pollution – is a major challenge to the restoration and conservation of marine biodiversity. Synthesizing the latest research into marine biodiversity conservation and fisheries management, this book provides regional and global perspectives on the role of Marine Protected Areas (MPAs) in confronting this challenge. The approach is multidisciplinary, covering all the fields involved in designating and assessing MPAs: ecology, fisheries science, statistics, economics, sociology and genetics. The book is structured around key topics, including threats to marine ecosystems and resources, the effects and effectiveness of MPAs and the scaling-up of MPA systems. Both theoretical and empirical approaches are considered. Recognizing the diversity of MPA sciences, the book also includes one part designed specifically as a practical guide to implementing scientific assessment studies of MPAs and monitoring programs.
Fully Protected Marine Reserves
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Author : Callum M. Roberts
language : en
Publisher:
Release Date : 2000
Fully Protected Marine Reserves written by Callum M. Roberts and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2000 with Biodiversity conservation categories.
Coral Reef Fish Habitat Associations And Implications For Research Monitoring And The Design Of Marine Protected Areas
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Author : Benjamin Michael Fitzpatrick
language : en
Publisher:
Release Date : 2012
Coral Reef Fish Habitat Associations And Implications For Research Monitoring And The Design Of Marine Protected Areas written by Benjamin Michael Fitzpatrick and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2012 with categories.
[Truncated abstract] The goal of this work was to investigate the finescale habitat associations and determine the effect of human impacts on coral reef fish assemblages. Initially I investigate how finescale spatial habitat variation influences the distribution and abundance of coral reef fishes. Significant variation in the reef fish assemblage was driven by variation in habitat. Consequently finescale habitat variation needs be accounted for in spatial or temporal surveys of coral fish assemblages. My second question investigated how protection from fishing influences the overall variation in coral reef fish assemblages, while my third question investigated how consistent the differences in protected fish assemblages are through time. Protection from fishing accounted for significantly more variation in fish assemblages than that explained by finescale habitat alone. This was driven by an average abundance and length of target species being higher inside sanctuaries and a response in non-target species indicating that there are some trophic interactions occurring between fishes. I found that both target and non-target species can be more abundant at protected reefscapes through time, consistent with the theory that protected areas can achieve recovery and lasting maintenance of fish assemblage structure relative to adjacent fished locations. I also investigated how fish assemblages within shallow coral reef habitats differ to those of adjacent continental shelf habitats to a depth of 100m. Cross-shelf sampling produced significant new knowledge on the depth and habitat specificity of many species previously only known from shallow coral reef environments. Many target species protected by shallow water protected areas are found as adults in unpotected shelf waters suggesting shallow water protected areas alone may not be effective for all species equally. Expanded depth distributions for many species revealed some refuge at depth from shallow water climate related impacts, though it is uncertain how this might contribute to persistence in populations at a local or regional scale. Many species are confined to one or a few shallow water habitats for their entire post recruitment lifehistory as opposed to others that can range across many. Fish assemblages associated with deeper water habitats are composed of higher order predators and high numbers of unique species, suggesting they will respond very differently to shallow waters when impacted by fisheries. Diversity and unique species associated with deep water habitats approached those found at shallow coral reef habitats. Habitat specialization changes dramatically from species to species and was not easily predicted. This research holds a number of key implications. Firstly the design of coral reef marine protected areas and associated monitoring programs should account for variation in benthic habitat. Fishing and other human impacts affect significantly different elements of coral reef fish assemblages depending upon the biological and physical parameters of the benthic habitat found. Marine protected areas should incorporate this habitat variability wherever practical, as discrete elements of trophic structure were significantly associated with different habitats...
Fish Visual Census In Marine Protected Areas
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Author :
language : en
Publisher:
Release Date : 1999
Fish Visual Census In Marine Protected Areas written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1999 with Fishes categories.
Marine Protected Areas
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Author : National Research Council
language : en
Publisher: National Academies Press
Release Date : 2001-06-01
Marine Protected Areas written by National Research Council and has been published by National Academies Press this book supported file pdf, txt, epub, kindle and other format this book has been release on 2001-06-01 with Science categories.
Although the ocean-and the resources within-seem limitless, there is clear evidence that human impacts such as overfishing, habitat destruction, and pollution disrupt marine ecosystems and threaten the long-term productivity of the seas. Declining yields in many fisheries and decay of treasured marine habitats, such as coral reefs, has heightened interest in establishing a comprehensive system of marine protected areas (MPAs)-areas designated for special protection to enhance the management of marine resources. Therefore, there is an urgent need to evaluate how MPAs can be employed in the United States and internationally as tools to support specific conservation needs of marine and coastal waters. Marine Protected Areas compares conventional management of marine resources with proposals to augment these management strategies with a system of protected areas. The volume argues that implementation of MPAs should be incremental and adaptive, through the design of areas not only to conserve resources, but also to help us learn how to manage marine species more effectively.