Made available in DSpace on 2014-06-11T19:35:43Z (GMT). No. of bitstreams: 0 Previous issue date: 2006-09-29Bitstream added on 2014-06-13T19:05:54Z : No. of bitstreams: 1 sazima_c_dr_rcla.pdf: 3777460 bytes, checksum: 9e503b696e86d7b22cab018e597016c7 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Acompanhar animais em atividade alimentar constitui um modo comum de forragear para peixes recifais que formam associações alimentares interespecíficas. Os peixes seguidores acompanham animais nucleares para aproveitar itens alimentares expostos ou produzidos através da atividade do nuclear. Tais associações alimentares são comuns para diversos tipos de peixes e outros animais, ocorrendo em variadas áreas geográficas. Este tipo de associação alimentar foi estudado no arquipélago oceânico de Fernando de Noronha, Atlântico Sul Ocidental tropical. O presente trabalho é composto de cinco artigos científicos, dispostos em quatro capítulos. O primeiro capítulo descreve associações alimentares entre peixes recifais e tartarugas marinhas. O segundo capítulo caracteriza o comportamento alimentar versátil de uma espécie de peixe recifal ao seguir outras espécies de peixes. O terceiro capítulo é composto de dois artigos; o primeiro trata da espécie de peixe nuclear mais comum e importante no arquipélago, ao passo que o segundo artigo descreve a associação entre seguidores e uma espécie de peixe cuja família não constava como nuclear. O quarto capítulo constitui uma revisão geral sobre o tema, com informações sobre o grupo de animais, na maioria peixes recifais, que forma associações alimentares interespecíficas como nucleares e/ou seguidores. A série de artigos científicos, apresentada no presente trabalho, amplia o conhecimento sobre agrupamentos alimentares e história natural da ictiofauna recifal no Atlântico Sul Ocidental tropical, além de modificar a situação deste tipo de associação alimentar na literatura científica mundial. / Following behaviour is a foraging mode commonly recorded for reef fishes during heterospecific feeding associations. The followers escort so called nuclear foraging fishes and other animals to capitalise on food items exposed or produced by the activity of the nuclear ones. Such foraging associations are widespread and recorded for several fish and other marine animal taxa and geographic areas. This foraging mode was studied at the oceanic archipelago of Fernando de Noronha, tropical Southwest Atlantic. The present work is composed of five scientific papers, organized in four chapters. The first chapter describes foraging associations between reef fishes and marine turtles. The second chapter characterizes the variable foraging modes of a reef fish species while following other fishes. The third chapter is composed by two studies, the first dealing with the commonest and most important nuclear fish in the archipelago, while the second one describes the association between followers and a fish species in a family not previously recorded as a nuclear. The fourth chapter is an overview about this topic, with information about the assemblage of animals, mostly reef fishes, which engage in interspecific foraging associations as nuclears and/or followers. This series of articles broadens our understanding about feeding assemblages and natural history of reef fishes in the tropical Southwest Atlantic, besides modifying the knowledge on this type of foraging association.

Herbivory is a key process that mediates the abundance of primary producers and community composition in both terrestrial and aquatic ecosystems. On tropical coral reefs, changes in herbivory are often related to phase shifts between coral-dominance and dominance by seaweeds, or foliose macroalgae. Resilience or capacity to resist and reverse such phase shifts is, therefore, viewed as a critical function on coral reefs. This thesis used grazer exclusion and assay experiments at six sites within three different fisheries management regimes in Kenya to identify the impacts of herbivores (sea urchins and fishes) on algal dynamics in the context of coral reef resilience. First, I examined the grazing rates necessary to prevent phase shifts by quantifying consumption and algal production. Here, I found that, over a 390-day experiment, at least 50 percent of algal production must be consumed to avoid accumulation of algal biomass. Using video observations, I also showed that scraping parrotfishes remove more algae (per unit of fish biomass) than previously assumed, and that sea urchins, if released from predation, have similar impacts to fishes. Then I focused on algal succession, and found that sea urchins and fishes have different effects that are mediated by their abundances and species composition. Where sea urchins were less abundant and parrotfishes absent (e.g. young fisheries closures), progression of algae from turfs to early and then late successional macroalgae occurred rapidly and within 100 days. I then turned my focus to the removal of already established macroalgae (grown for > 1 yr in the absence of herbivores) and showed that sea urchins and browsing fishes were able to remove significant amounts of macroalgae where either herbivore was abundant. However, using multiple-choice selectivity assays and in situ video recordings, I found that browsing fishes fed very selectively with low overlap in diet among species, leading to low functional redundancy within a high diversity system. Finally, using long-term survey data (from 28 sites) to build a 43-year chronosequence, I showed that it is possible that the effects of herbivory will not be constant across transitions from open fishing to fishery closures through non-linear grazing intensity. Therefore, increases in herbivory within fisheries closures may not be immediate and may allow a window of opportunity for algae to go from turf to unpalatable macroalgae until scraping and browsing fishes fully recover from fishing (~ 20 years). The findings in this thesis are novel and raise concern over the potential implications of the slow recovery of parrotfishes or, given lower than expected functional redundancy in grazing effects, the absence of even one browsing fish species in fisheries closures. Overall, this thesis highlights the importance of herbivore community dynamics in mediating interactions among algae, and provides new insights for conservation and management actions that attempt to bolster the resilience of coral reefs.

Made available in DSpace on 2014-12-17T14:02:03Z (GMT). No. of bitstreams: 1 IgorEGP.pdf: 595581 bytes, checksum: 209975fcf9ad63e6f448af856207e81a (MD5) Previous issue date: 2006-12-06 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / The present work was carried out at the Atol das Rocas (3? 51 S; 33? 49 W), the only atoll of the South Atlantic and the first Brazilian marine protected area. It was guided by the following hypothesis: the composition of the fish communities varies in agreement with the position of the pools; in other words, with or without permanent ocean connection. To test the validity of this hypothesis, the fish abundance was estimated in the connected pools (Barretinha/Barreta Falsa) and unconnected ones (Cemiteriozinho/?ncoras), carrying an ecological characterization of the fishes that inhabit these pools. Additionally, the structural complexity of the sampled places was also evaluated intending to verify the variations of the abundance and diversity of fishes in function to this factor. By the fact of this research was being carried out through the limits of a conservation unit, the samples was realized using visual census techniques. The results generated through uni and multivariate analytic techniques allowed the evidence that decisive factor in the density, richness and diversity variations of fishes are linked to the substratum type (Hard / Soft bottom) and not by the fact that the pool are or are not connected permanently to the ocean. In relation to the structural complexity; 58% of the variations in the diversity of fishes were attributed to changes in the structural complexity, while 12% of the variations in the abundance were attributed to the structural complexity / Este trabalho realizado no Atol das Rocas (3? 51 S; 33? 49 W), o ?nico atol do Atl?ntico Sul e a primeira ?rea marinha protegida brasileira, foi norteado pela hip?tese de que: a composi??o das comunidades de peixes varia de acordo com a posi??o das piscinas; ou seja, com ou sem conex?o permanente com o oceano. Para testar a validade desta hip?tese foram realizadas estimativas da abund?ncia de peixes em piscinas conectadas (Barretinha/Barreta Falsa) e n?o conectadas com oceano (Cemiteriozinho/?ncoras), realizando uma caracteriza??o ecol?gica dos peixes que habitam estas piscinas. Adicionalmente a complexidade estrutural dos locais amostrados tamb?m foi avaliada, com intuito de verificar varia??es da abund?ncia e diversidade de peixes em fun??o deste fator. Pelo fato desta pesquisa ter sido realizada dentro dos limites de uma unidade de conserva??o, as amostragens foram realizadas atrav?s do censo visual. Um total de 56 esp?cies foram identificadas no estudo piloto e durante as amostragens 48 destas foram observadas. Os resultados gerados atrav?s de t?cnicas anal?ticas uni e multivariadas permitiram constatar que o fator determinante nas varia??es de densidade, riqueza e diversidade dos peixes ? o tipo de substrato (consolidados/n?o consolidados) e n?o fato das piscinas estarem ou n?o conectada permanentemente com oceano. Com rela??o ? complexidade estrutural; 58% das varia??es na diversidade de peixes s?o atribu?das a mudan?as na complexidade estrutural enquanto que 12% das varia??es na abund?ncia s?o atribu?dos a este fator

Orientadores: Fosca Pedini Pereira Leite, Sergio Ricardo Floeter / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-16T19:50:45Z (GMT). No. of bitstreams: 1 Krajewski_JoaoPaulo.pdf: 9575479 bytes, checksum: 263e857c27328008c50d4b577be61438 (MD5) Previous issue date: 2010 / Resumo: Os recifes proporcionam abrigo e alimento para diversas espécies de peixes e, portanto, pode haver uma relação entre a distribuição e comportamento de peixes recifais e a composição de substratos do recife. Fatores físicos, especialmente o hidrodinamismo e profundidade, também parecem ter grande influência sobre a distribuição e comportamento de algumas espécies de peixes recifais. No presente estudo a relação entre a distribuição e atividade de espécies de peixes, especialmente as que se alimentam de invertebrados bentônicos (zoobentivoras), e a composição de substratos do recife, hidrodinamismo e profundidade foi estudada em recifes do arquipélago de Fernando de Noronha, Pernambuco. As principais espécies zoobentivoras de Fernando de Noronha forrageiam principalmente sobre substratos compostos por algas filamentosas verdes e vermelhas e algas pardas cobertas de sedimento, e sua atividade alimentar não é distribuída proporcionalmente à abundância relativa dos diferentes substratos. Ainda, para algumas espécies, o uso de substrato pode variar entre recifes. A dieta principal dos zoobentívoros mais abundantes em Fernando de Noronha são poliquetas e crustáceos. Quatro espécies foram estudadas quanto à variação de sua atividade entre diferentes recifes. Haemulon chrysargyreum, Halichoeres radiatus, e Cephalopholis fulva em geral parecem evitar nadar na coluna d'água quando há maior batimento de ondas. Por outro lado, Thalassoma norohhanum não varia seu comportamento em função do hidrodinamismo. A presença de distúrbio no substrato também pode influenciar o comportamento dos peixes recifais de Fernando de Noronha, uma vez que experimentalmente foi demonstrado que espécies carnívoras oportunistas são atraídas por distúrbios causados no substrato não consolidado. Em geral, o hidrodinamismo é o principal fator que influencia a distribuição e comportamento de peixes recifais em Fernando de Noronha, especialmente os planctívoros e alguns herbívoros. A abundância e biomassa de peixes em geral foi maior em recifes com menor hidrodinamismo, mais fundos (>10m) e maior cobertura de corais. Os peixes zoobentívoros de Fernando de Noronha, porém, aparentam ser generalistas na escolha de substrato de forrageamento e habitat e, portanto, parece não haver relação entre sua abundância e a disponibilidade de seus principais substratos de forrageamento. / Abstract: Reefs provide shelter and food for several fish species and, thus, there may be a correlation between the abundance and behaviour of fishes and the reef bottom composition-Physical factors, such as water movement and depth, may also have a profound impact in species distribuiton and activity on reefs. Here, the possible relationship between the distribution and activity of reef fishes, mainly benthic carnivores, and reef bottom composition, water movement and depth was studied in the Fernando de Noronha Archipelago, off Northeast Brazil. The main benthic carnivorous fishes at the archipelago forage mostly on substrata composed by filamentous and brown algae covered by sediments, and the different types of substrata present on reefs were used disproportionaly to their availability. Some studied species also varied their foraging substratum selection between nearby reefs. The main items in the diet of the benthic carnivorous fishes were polychaetes and crustaceans. We also studied the local variation in the activity of four fish species, and Haemulon chrysargyreum, Halichoeres radiatus, e Cephalopholis fulva tended to avoid swimming in the water column when there was higher water movement. On the other hand, Thalassoma noronhanum did not vary its activity with diferent degres of water movement. We also recorded that the presence of substratum disturbance on soft sediments may alter the activity of opportunistic carnivorous fishes, since they were attracted by disturbance on the bottom caused experimentaly and started to forage in the area where the substratum was disturbed. In general, water movement was the main factor influencing the fish communities in Fernando de Noronha, especially of herbivorous and planktivorous fishes. Abundance and biomass of fishes in general were greater in reefs with less water movement, deeper (>10m) and whith more coral cover. The benthic carnivorous fishes of Fernando de Noronha, however, were mostly versatile in their habitat use and foraging substratum selection and its distribution seem not to be influenced by the avalability of their main foraging substratum. / Tese (doutotrado) - Universida / Ecologia / Doutor em Ecologia

Marine Protected Areas (MPAs), the Ecosystem Approach to Fisheries management (EAF) and Integrated Coastal Management (ICM) have been identified as possible alternatives to traditional linefish management measures, which have largely failed. Monitoring and assessment of fish communities on a long-term basis is necessary, and will provide a means to evaluate the effectiveness of such management measures. Therefore, standardised protocols and optimal sampling methods for long-term monitoring (LTM) and assessment of coastal fish communities are essential. This study aimed to identify suitable methods and develop a protocol for assessment of inshore reef fish communities. A suitable location for evaluation of proposed methods was identified in the warm temperate biogeographical region of South Africa, encompassing the well-established Tsitsikamma Coastal National Park MPA and an adjacent exploited area. Chrysoblephus laticeps (roman) was identified as an indicator species for the study, as it has been well-studied and is well represented in the area. Underwater visual census (UVC) and controlled fishing were identified as suitable methods. UVC transects were found to be superior to point counts, in terms of sampling efficiency, variability, bias and required sample size. An effort of two angler hours per fishing station was shown to provide low catch variability, while at the same time a representative catch and low overall cost and required time. The methods were incorporated in a proposed sampling protocol, and evaluated. The methods were able to detect known differences between protected and exploited communities. It is recommended that LTM within protected areas, for detection of natural change, be focused on community-level indicators, while LTM in exploited areas, aimed at detection of anthropogenic change, be focused on species-level indicators. The proposed protocol with standardised methods will allow for comparisons across a network of LTM sites and provide the opportunity for a broad-scale assessment of the effects of environmental variables on reef fish stocks. The protocol developed in this study has application in other biogeographical regions in South Africa, and other parts of the world. Shift in the focus of much marine research, in South Africa and elsewhere, to LTM, highlights the relevance and timeous nature of this study.

Under the guidance of the new coastal management policies within South Africa this thesis advocates a more integrated, co-operative approach to local coastal management. The project aimed to acquire baseline information on the local nearshore fishery and resource state and to propose a set of indicators that could be incorporated into the new management strategy. To gather the required information the project was split into two parts: 1) An assessment of the local linefisheries and 2) A comparative study of the reef fish community structure between exploited and unexploited reefs. The local linefisheries were assessed through the use of launch records, commercial catch records, access point and boat based surveys. A questionnaire was used to gather data on catch and effort, fisher demographics, fisher attitudes towards and knowledge of the current management regulations, assess the efficacy of the fisheries inspectorate and highlight spatial areas of fishing pressure. A total of 252 interviews and catch inspections were conducted. Total effort for the ski-boat fishery estimated from the access point survey was 890 boat days.year⁻¹ or 3560 fisher days. year⁻¹ compared to 736 boat days.year⁻¹ or 2944 fisher days. year⁻¹ recorded in the launch records. Effort was seasonal with greater pressure occurring over the summer holiday period. Analysis of the catch showed that Merluccius capensis, Argyrozona argyrozona, Argyrosomus inodorus, Chrysoblephus laticeps and Atractoscion aequidens were the most frequently caught species. The overall CPUE was 3.00±5.54kg.fisher⁻¹.day⁻¹ or 4.71±4.117 fish.fisher⁻¹.day⁻¹. Estimated targeted CPUE was 0.91±0.67kg.fisher⁻¹.day⁻¹ or 0.97±0.77 fish.fisher⁻¹.day⁻¹ for C. laticeps, 8.47±8.57kg.fisher⁻¹.day⁻¹ or 1.24±1.16 fish.fisher⁻¹.day⁻¹ for A. aequidens and 2.05±3.78kg.fisher⁻¹.day⁻¹ or 1.10±1.80 fish.fisher⁻¹.day⁻¹ for A. inodorus. Issues identified included poor fisher knowledge regarding linefish regulations, the low occurrence of fishery inspections and a limited degree of noncompliance. Although most fishers supported the current linefish management regulations, when tested on the size limits, bag limits and closed seasons of their target species a high proportion of fishers did not know the regulations (recreational 64%, charter 53%, commercial 42%). Furthermore only 27% of fishers had had their catch inspected whilst fishing in Plettenberg Bay and the majority of these had only been inspected once. Just over half the interviewees (60%) indicated that fishing had deteriorated within Plettenberg Bay with fewer and smaller fish being caught. The most common causes cited for this decline were commercial and recreational overfishing respectively. Underwater point counts and experimental angling were used to rapidly assess the state of the reef fish resource in Plettenberg Bay through a comparative study of the community structure between two exploited sites in Plettenberg Bay and two protected sites within the Tsitsikamma National Park. Generalized linear modeling showed that relative density of certain species was significantly different between the protected reefs inside the TNP and those exploited reefs within Plettenberg Bay. Both P. rupestris and C. laticeps had greater densities within the protected area whilst Chisquared tests showed that the size frequency distributions were significantly different with larger size-classes and the maximum size of fish greater within the reserve. These trends were noted with both the underwater visual surveys and the experimental angling. Multi-dimensional scaling and cluster analysis showed that there was an overall difference in the community structure between the study sites. It is hypothesised that through removal of key reef species and larger individuals that fishing has directly and indirectly affected the overall community structure. Within a simple framework based on ecological, institutional and social sustainability domains along with the results of the study area, a set of indicators is proposed and the sustainability of the local fishery scored within a rapid assessment matrix. The socio-economic domain scored the highest (83%) whilst the institutional domain scored the lowest (8.3%) and the ecological domain scored 25%, giving a total sustainability score of 38.8%. The results of this matrix show that at present the local fishery is non-sustainable and in need of greater management. By synthesizing papers dealing with and based on the concepts involved in Integrated Coastal Management, a structured approach is proposed to developing and implementing more holistic local coastal governance. It is envisaged that the framework to implement such an approach should be through the development of a local Coastal Management Plan and a subsidiary Bay Management Plan. Although stakeholder participation and representation is an essential component in the development of these plans, it is recommended that the local municipality should be the lead agent and incorporate the plans into the local Integrated Development and Spatial Plans thereby gaining long term local government support.

White steenbras Lithognathus lithognathus (Pisces: Sparidae) has been a major target species of numerous fisheries in South Africa, since the late 19th century. Historically, it contributed substantially to annual catches in commercial net fisheries, and became dominant in recreational shore catches in the latter half of the 20th century. However, overexploitation in both sectors resulted in severe declines in abundance. The ultimate collapse of the stock by the end of the last century, and the failure of traditional management measures to protect the species indicate that a new management approach for this species is necessary. The species was identified as a priority for research, management and conservation in a National Linefish Status Report. Despite knowledge on aspects of its biology and life history, little is known about juvenile habitat use patterns, home range dynamics and movement behaviour in estuaries. Similarly, the movement and migration of larger juveniles and adults in the marine environment are poorly understood. Furthermore, there is a complete lack of information on its genetic stock structure. Such information is essential for effective management of a fishery species. This thesis aimed to address the gaps in the understanding of white steenbras movement patterns and genetic stock structure, and provide an assessment of its current conservation status. The study adopted a multidisciplinary approach, incorporating a range of methods and drawing on available information, including published literature, unpublished reports and data from long-term monitoring programmes. Acoustic telemetry, conducted in a range of estuaries, showed high site fidelity, restricted area use, small home ranges relative to the size of the estuary, and a high level of residency within estuaries at the early juvenile life stage. Behaviour within estuaries was dominated by station-keeping, superimposed by a strong diel behaviour, presumably based on feeding and/or predator avoidance, with individuals entering the shallow littoral zone at night to feed, and seeking refuge in the deeper channel areas during the daytime. Conventional dart tagging and recapture data from four ongoing, long-term coastal fish tagging projects, spread throughout the distribution of this species, indicated high levels of residency in the surf zone at the late juvenile and sub-adult life stages. Consequently, juvenile and sub-adult white steenbras are vulnerable to localised depletion, although they can be effectively protected by suitably positioned estuarine protected areas (EPAs) and marine protected areas (MPAs), respectively. It has been hypothesized that adult white steenbras undertake large-scale coastal migrations between summer aggregation areas and winter spawning grounds. The scale of observed coastal movements was correlated with fish size (and age), with larger fish undertaking considerably longer-distance coastal movements than smaller individuals, supporting this hypothesis. Given the migratory behaviour of adults, and indications that limited spawning habitat exists, MPAs designed to protect white steenbras during the adult life stage should encompass all known spawning aggregation sites. The fishery is plagued by problems such as low compliance and low enforcement capacity, and alternative management measures, such as seasonal closure, need to be evaluated. Despite considerable conventional dart tagging effort around the coastline (5 782 fish tagged) with 292 recaptures there remains a lack of empirical evidence of fish migrating long distances (> 600 km) between aggregation and spawning areas. This uncertainty in the level of connectivity among coastal regions was addressed using mitochondrial DNA sequencing and genotyping of microsatellite repeat loci in the nuclear genome, which showed no evidence of major geographic barriers to gene flow in this species. Samples collected throughout the white steenbras core distribution showed high genetic diversity, low genetic differentiation and no evidence of isolation by distance or localised spawning. Although historically dominant in several fisheries, analysis of long-term commercial and recreational catch data for white steenbras indicated considerable declines and ultimately stock collapse. Improved catch-per-unit-effort in two large MPAs subsequent to closure confirmed that MPAs can be effective for the protection of white steenbras. However, the current MPA network encompasses a low proportion of sandy shoreline, for which white steenbras exhibits an affinity. Many MPAs do not prohibit recreational shore angling, which currently accounts for the greatest proportion of the total annual catch. Furthermore, EPAs within the juvenile distribution protect a negligible proportion of the total available surface area of estuaries – habitat on which white steenbras is wholly dependent. Despite some evidence of recent increases in abundance in estuaries and the surf zone in certain areas, white steenbras meets the criteria for “Endangered” on the IUCN Red List of Threatened Species, and for “Protected species” status on the National Environmental Management: Biodiversity Act of South Africa. The species requires improved management, with consideration for its life-history style, estuarine dependency, surf zone residency, predictable spawning migrations and its poor conservation status. The multidisciplinary approach provides valuable information towards an improved scientific basis for the management of white steenbras and a framework for research that can be adopted for other overexploited, estuarine-associated coastal fishery species.

This thesis investigates the movement behaviour of South African two coastal fish species and evaluates the effectiveness of marine protected areas (MPAs) in their protection and management. Its primary focus is on resolving the movement patterns of roman Chrysoblephus laticeps (Sparidae) in and around the Goukamma and Castle Rock MPAs in the Western Cape province of South Africa. A pilot study of the methodology investigated the movement behaviour of spotted grunter Pomadasys commersonnii (Haemulidae) in the sheltered East Kleinmonde Estuary in the Eastern Cape province. The application of different tagging methods was tested in a controlled tank experiment. Tagged roman were monitored over a 198-day period. Barbed dart, t-bar anchor and Visible Implanted Fluorescent Elastomer (VIFE) tags were compared. Application techniques and underwater visibility of VIFE tags were tested on roman and on fransmadam Boobsoidia inornata in a pilot study. Needles of gauge 25 were found to be optimal for VIFE tag application. Whereas VIFE tagging caused fin rot in fransmadam, it had no negative effect on roman. VIFE tagged fish could be identified by divers from a distance of three metres under ambient light in an observation tank in five metres water depth. There was no significant difference in growth rate between groups of roman with different tags and controls after 198 days. High tag loss rates were experienced for barbed dart and t-bar anchor tags, although barbed dart tags performed better than t-bar anchor tags. Although some of the VIFE marks had deteriorated, all VIFE tagged fish were individually recognised at the end of the study. Conventional dart and VIFE tags are feasible methods to tag roman. However, the high tag loss rate of conventional tags must be taken into account in the design of a tagging study. Previous mark and recapture studies on roman are beset with a number of problems. Poor experimental design and low precision of capture positions resulted in equivocal results of limited value. A tagging experiment was designed to eliminate ambiguity in data interpretation and to produce a dataset that could be used to model roman residency and dispersal. A combination of conventional barbed dart tags and Visible Implanted Fluorescent Elastomer tags was used to tag roman in the Goukamma Marine Protected Area (GMPA) on the temperate South African south coast. Sixty one percent of roman were recaptured within 50 m of the tagging position. A small proportion moved considerable distances of up to four kilometres. The extent of these movements was not dependent on fish size or sex. Data from this experiment and from a previous tagging study in the Tsitsikamma National Park (TNP) were used to model the resident behaviour of roman. The model suggests a probability of 91% (GMPA) and 94% (TNP) of residency within a 10000 m² cell. This result suggests that individual roman will benefit from protection in small MPAs. A different experimental approach was required to investigate the exact home range of this species. Firstly the feasibility of using acoustic telemetry to study the movement of coastal fish in South Africa was investigated. The telemetry equipment comprised two VEMCO V8 transmitters and a VEMCO VR60 receiver linked to a directional hydrophone. A tank experiment was conducted to examine the effects of the transmitter implantation. A tracking experiment was conducted on spotted grunter Pomadasys commersonnii in the East Kleinmonde Estuary. Operated fish recovered quickly and, with respect to swimming behaviour and growth rates, no differences were found between fish with implants and controls. The maximum detection range in the estuary was 400 m. Interference between different transmitter frequencies was negligible. Transmitter location recordings were found to be accurate within five metres. Two fish were tracked over a seven-day period. The fish preferred the lower reaches of the estuary where they made repeated and prolonged use of specific areas. The success of the initial experiments allowed this method to be used to investigate the spatial utilisation and activity patterns of roman Chrysoblephus laticeps. Surgically implanted VEMCO V8, V13 and V16 transmitters were used to track 13 roman inside the Castle Rock MPA in False Bay. Transmitters implanted into C. laticeps in tanks had no apparent effects on growth and physiology. Manual boatand diver-based tracking experiments covered a 17-month period. A VEMCO VRAP radio acoustic positioning system was used over two one-month periods during and after the spawning season of roman. Analysis of data using a 95% fixed kernel algorithm suggests that roman are resident throughout their adult life, occupying home ranges between 1000 and 3000 m². Activity was lower at night. During periods of cold-water upwelling, fish retreated into caves. During the spawning season, females extended their home ranges, possibly to mate with different males. These results confirm that this species is well suited for protection and management with small MPAs. The effect of two MPAs on the South African south coast on the population of C. laticeps was simulated with a spatially explicit individual based model (IBM). Life history parameters determined in recent studies and the effect of fishing on the size of sex change was taken into account. Fish densities and size frequencies were based on recent underwater visual census. The distribution of suitable habitat in the study areas was also incorporated. The results show a rapid recovery of the fish size frequency spectrum and sex ratio to pre-exploitation levels inside both MPAs. Little 'spillover' of fish into the fished areas occurred resulting in negligible improvement of catches. The results suggest that for resident species like roman, even small MPAs offer sufficient protection.

Coral reefs around the world are threatened by a variety of sources, from localized impacts, including overfishing and coastal development, to global temperature increases and ocean acidification. Conserving these marine biodiversity havens requires both global and local action informed by scientific research. In this thesis, I use data collected from the coral reefs around Kiritimati atoll (Republic of Kiribati) in the central equatorial Pacific, first to assess the applicability of two common metrics used in passive underwater acoustic research, and second to examine the effects of a marine heatwave and local human disturbance on an assemblage of corallivorous fish. Using acoustic data recorded in 2017 and 2018 on reefs around Kiritimati, I assess how sound pressure level (SPL) and the acoustic complexity index (ACI) respond to changes in fish sounds in a low frequency band (160 Hz – 1 kHz) and snapping shrimp snaps in a high frequency band (1 kHz – 22 kHz). I found that while SPL was positively correlated with increases in fish sounds and snap density, changes in ACI were dependent upon the settings chosen for its calculation, with the density of snaps negatively correlated with ACI across all settings. These findings provide evidence that despite its quick and prolific adoption, acoustic metrics like ACI should be thoroughly field-tested and standardized before they are applied to new ecosystems like coral reefs. Next, using underwater visual censuses (UVCs) of reef fish assemblages, I quantified how two functional groups of corallivores, obligate and facultative, responded to a mass coral mortality event created by the 2015-2016 El Niño. Declines in abundance of both groups were largely driven by the response of coral-associated damselfishes, Plectroglyphidodon johnstonianus in the obligate group and Plectroglyphidodon dickii in the facultative group, to heat stress and subsequent coral mortality. I also observed a significant decline in the species richness of obligate corallivores, and a continued decline in the abundance of obligate corallivores three years after the mass coral mortality event. Additionally, facultative corallivore abundance increased with disturbance, although the effect was modulated by year, likely due to their more adaptable diets. Corallivore assemblage structure was also influenced by the heat stress event, recovery, and local human disturbance. These results detail how an entire corallivorous assemblage is impacted by a coral mortality event and incidentally provide a timeline for corallivore decline. Together, these results provide information about new ways of monitoring coral reefs, and the ways in which two components of the reef fish community, obligate and facultative corallivores, respond to a mass coral mortality event. / Graduate / 2022-01-15

Coral reefs are being negatively impacted by various causes worldwide, and direct intervention is often warranted following disturbance to restore or replace lost ecosystem structure and function. An experimental coral reef restoration study involving standardized artificial reef modules (ReefballsTM) was conducted in Mexico’s Yucatan Peninsula in the towns of Puerto Morelos and Akumal. The purpose was to explore the use of artificial structure for restoration and mitigation applications in a highly diverse and dynamic Caribbean coral reef environment by applying and evaluating the performance of select experimental treatments hypothesized to accelerate development of the associated biota. The first treatment consisted of invertebrate enhancing artificial substrate padding material, which provided structurally complex refuge space for mobile epifaunal/infaunal invertebrates and other benthic organisms. The second treatment consisted of coral transplants, intended to provide additional structural complexity and kick-start development of stony coral populations. The third treatment consisted of settlement plates which were intended to provide data on coral recruitment and survival rates. Multiple hypotheses relating to the interactions between experimental treatments and the resulting macroalgal, non-coral invertebrate, stony coral, and coral reef fish assemblages were examined, and comparisons were made between natural and artificial substrates. In Puerto Morelos there were 40 modules; 10 controls and 10 of each of 3 treatments: substrate pads, coral transplants, and settlement plates. In Akumal there were 12 modules; 6 controls and 3 of each of 2 treatments: substrate pads and settlement plates. Following module deployment, 6 biannual monitoring trips were made over the course of three years to assess the development of the biota, with a final 7th trip made six years post-deployment. Divers conducted non-destructive visual surveys to evaluate total abundance, species richness, size class distribution, and assemblage structure of coral reef fishes. Other monitoring work included coral recruit surveys, mobile epifaunal invertebrate collections from substrate pads, and digital imaging of coral transplants, natural reef reference corals, and benthic quadrat areas. Hurricane Dean compromised the Akumal study site during the first year of the study, but Puerto Morelos was unaffected. There the modules developed biotic assemblages that differed from what was found on the natural reef, and the data suggests that the substrate pads may have had an effect on the development of faunal assemblages. Lobophora variegata macroaglae and Desmapsamma anchorata sponge were the major contributors to benthic community composition, and both had significantly greater coverage on the substrate pads treatment modules. Lobophora grew rapidly and peaked within the first year, while sponges increased steadily throughout the first three years of the study, surpassing the coverage of macroalgae before the end of the second year, much to the detriment of coral transplants and many coral recruits. By the end of the study, over 75% of the transplants were overgrown by D. anchorata, and density of new coral recruits on the Pads treatment modules was lower than the other treatments and controls. Coral recruitment was dominated by Porites astreoides on all treatments and controls, and the number of corals increased steadily throughout the study. The controls had consistently greater numbers of corals than the treatments, as well as lower percent coverage of macroalgae and sponges. Total abundance and species richness of reef fishes was generally unaffected by the treatments. However, at the family and species level, several differences were detected, particularly for the substrate pads treatment and to a lesser extent for the coral transplants treatment. For future restoration or mitigation efforts utilizing similar or identical treatments to artificial substrates, this study suggests that, in the absence of routine maintenance, greater success may be achieved after waiting several years post-deployment for the initial wave of unchecked growth by benthic organisms (i.e., macroalgae and sponges) to reach a balance point before a large investment of resources is devoted to coral transplanting. Further recommendations include routine monthly or quarterly on-site maintenance to enhance transplant survival, as well as a longer monitoring window to assess community development in response to experimental treatments. The results of this study suggest that the experimental treatments did indeed have an effect on the biota, but whether or not the effect was beneficial largely depends upon perspective. The Pads treatment in particular had the greatest effect on both reef fish and benthic community development, however, it was not beneficial for stony coral recruitment. Additional research is needed to fully understand the long-term performance and effects of the padding material on biotic assemblage development for future restoration or mitigation projects.