Artificial reefs may enhance the biological production of reef-associated flora and fauna, but their trophic structure relative to that of natural reefs remains understudied. We assessed trophic dynamics by comparing δ13C and δ15N in 43 fish species from artificial and natural reef tracts of Broward County, Florida. We tested the effect of sampling location (artificial, first, and second reef), general feeding strategy (herbivore, omnivore, planktivore, invertivore, and carnivore), phylogeny, and standard length. For all samples, δ13C and δ15N ranged from -19.5 to -13.1‰ and 6.7 to 13.3‰, respectively. Lower trophic level feeding behavior resulted in more depleted δ13C and δ15N and higher trophic level feeding behavior resulted in more enriched δ13C and δ15N. We detected significant effects of both general feeding strategy and phylogeny. We also detected significant differences in δ13C and δ15N profiles between artificial and natural reefs; however, these differences were not great enough to suggest changes in the feeding strategy or trophic dynamics of individual fish taxa.

Submitted by (edna.saturno@ufrpe.br) on 2017-02-09T15:28:12Z No. of bitstreams: 1 Diogo Silva de Oliveira.pdf: 828978 bytes, checksum: e077b5bb267ab11101ecfabc9b5887ee (MD5) / Made available in DSpace on 2017-02-09T15:28:12Z (GMT). No. of bitstreams: 1 Diogo Silva de Oliveira.pdf: 828978 bytes, checksum: e077b5bb267ab11101ecfabc9b5887ee (MD5) Previous issue date: 2012-02-27 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / From June 2009 to May 2011 were made 18 dives and accounted for approximately 17,572 individuals in 65 species 44 genera and 29 families. The number of indentified species, varied in each dive and the months with lowest and highest number of species in June 2009 (15 species) January 2011 (41 species). The most common species were Haemulon aurolineatum and Haemulon squamipinna with the formation of schools with approximately 1,000 and 2,000 individuals respectively representing 76,7% of the total individuals sampled. The most representative families were Labridae (10 species), Lutjanidae (6 species), Carangidae and Haemulidae with 5 species and Epinephelidae (4 species). The relationship between Shannon Winner (H’) and Pielou evenness (J), presented a decrease the first to the second year of sampling, reaching maximum values of H’=2.98, J=0.56 and H’=1.52, J=0.29 respectively. These values were significantly different (Kuskal Wallis = 12.87, p<0,05) between the diversity of the first year for the second sample, as well as the evenness (Kuskal Wallis = 12.82, p<0.05). The summer months had similarity (>80%) showing a homogeneous and diverse fish community. Some behaviors were possible to be observed in the artificial reef, as follower’s species, cleaning symbiosis, feeding and breeding. However, this artificial reef showed that despite the short time of installation has been great ecological importance because its great wealth and diversity of existing economic, as it protects the species from overfishing, because the government (State Decree 23.394/2001) making it a crime for some destructive practice this artificial environment. / No período de junho de 2009 a maio de 2011 foram realizados 18 mergulhos e contabilizadas aproximadamente 17572 individuos distribuidos em 65 espécies, 44 gêneros e 29 famílias. O número de espécies identificadas, variou em cada mergulho, tendo os meses com menor e maior número de espécie em, junho de 2009 (15 espécies) e janeiro de 2011 (41 espécies). As espécies mais comuns foram Haemulon aurolineatum e H. squamipinna, com a formação de cardumes com aproximadamente 1.000 e 2.000 indivíduos, respectivamente, e representando 76,7% do total de indivíduos amostrados. As famílias mais representativas foram Labridae, com 10 espécies; Lutjanidae (6 espécies), Haemulidae e Carangidae, com 5 espécies e Epinephelidae (4 espécies). A relação entre diversidade Shannon Winner (H’) e equitabilidade Pielou (J), apresentou um decréscimo do 1º para o 2º ano de amostragem, atingindo seus valores máximos de H’ = 2,98 J = 0,56 e H’ = 1,52; J = 0,29, respectivamentes. Esses valores foram significativamente diferentes (Kruskal Wallis =12,87; p<0.05) entre a diversidade do primeiro para o segundo ano amostral, assim como, na equitabilidade (Kruskal Wallis =12,82; p<0.05). Os meses de verão tiveram uma alta similaridade (>80%), mostrando uma comunidade ictia diversificada e homogênea. Alguns comportamentos foram possíveis de ser observados no recife artificial, como espécies seguidoras, simbiose de limpeza, alimentação, reprodução. Contudo, esse recife artificial mostrou que, apesar do pouco tempo de instalação está sendo de grande importância ecológica, devido sua grande riqueza e diversidade já existente, econômica, uma vez que protege espécies da pesca predatória, devido à lei (Decreto Estadual nº 23.394/ 2001) tornando crime qualquer prática destrutiva nesse ambiente artificial.

Coral reef fish larvae take an active role in selecting their settlement site and sensory cues may help them to orientate during this process. As settlement is a period of transition through which the majority of individuals do not survive, it is often a focal point for the management of coral reef populations, which are of high conservation concern. In this thesis, I used choice tests and in situ techniques to assess the response of settlement-stage larvae to a range of odour, light and acoustic cues and I found that larvae are more selective in their response to sensory stimuli than previously thought. Micro-habitat odours are not likely to be used during settlement orientation, and odour cues may be used to avoid inappropriate settlement sites. The photopositive behaviour of larval fish is likely to match their spectral sensitivity but this proved difficult to assess in situ because of the high amount of spatial and temporal variation in larval distribution. The positive response of settlement-stage fish to played back reef noise is location specific as well as being highly specific to the reef sound recording. To understand whether it might be the composition of reef sound that drives the selective response of larvae to acoustic cues, I took sound recordings while collecting visual data on fish diversity and the behavioural activity of a sound producing, or soniferous, fish species. I found that the variation in intensity of reef noise matches the activity patterns of a soniferous species, and when reef noise is most intense is when visual estimates on the diversity of the reef fish assemblage are decreased. This information provides the basis for understanding how changes in the reef soundscape may effect larval recruitment and has exciting implications for using sound recordings as a method to monitor coral reefs. Finally, I tested the viability of releasing reared larvae to boost depleted populations and found that collecting and holding settlement-stage fish for a week can increase survival, relative to natural settlement. These data demonstrate that applying our knowledge of the settlement behaviour of coral reef fish will make a significant contribution to developing tools for management.

A identificação dos grupos tróficos é fundamental para a compreensão dos fatores responsáveis pela organização e estruturação das comunidades. Nesse sentido, o presente estudo foi realizado nas poças de maré da Praia dos Castelhanos, situada no estado do Espírito Santo, região sudeste do Brasil, com o objetivo de descrever a organização trófica da comunidade de peixes, sob a hipótese de que essa organização é influenciada pelas variáveis ambientais das poças. As amostras foram coletadas em seis poças de maré, em campanhas trimestrais entre os anos de 2005 e 2007. A descrição da composição das dietas foi baseada nos valores do Índice Alimentar dos itens alimentares de doze espécies representativas do ambiente. Os principais itens das dietas foram os crustáceos bentônicos, principalmente copépodes e anfípodes, as algas, basicamente algas de tufo, e os poliquetas errantes. Por meio de análises de agrupamento a partir dos valores do Índice Alimentar dos itens que compõem a dieta de cada espécie e utilizando-se o índice de similaridade de Bray-Curtis, foram identificados oito grupos tróficos, sendo cinco de espécies carnívoras, dois de onívoras e um de herbívoras. Propõe-se que os principais fatores relacionados à formação desses grupos tróficos são a convergência de espécies na utilização de recursos alimentares abundantes e a variação de presas principais em função do tamanho do predador, diferenças de micro-habitat e a especialização trófica das espécies. Os resultados das análises de correlação canônica permitiram relacionar a distribuição dos grupos tróficos nas poças de maré tanto com as condições físico-químicas quanto com a interação entre a disponibilidade de micro-habitats e as relações ecológicas entre as espécies. Conclui-se que a organização trófica da comunidade de peixes de poças de maré da Praia dos Castelhanos é de fato influenciada pelas características ambientais das poças. / The identification of the trophic groups is fundamental to understanding the factors responsible for organizing and structuring the communities. Accordingly, the present study was conducted in the tidepools of Praia dos Castelhanos, located in the Espírito Santo State, southeastern Brazil, in order to describe the trophic organization of the fish community, under the assumption that this organization is influenced by the environmental variables of the pools. Samples were collected at six tidepools, in quarterly campaigns between 2005 and 2007. The description of the composition of the diets was based on the Feeding Index values of the food items of twelve species representative of the environment. The main items of the diets were benthic crustaceans, mainly copepods and amphipods, algae, basically turf algae, and errant polychaetes. Through cluster analysis from the values of the Feeding Index of food items that comprising the diet of each species and using the similarity index of Bray-Curtis, eight trophic groups were identified, five of carnivorous species, two of omnivorous and one of herbivorous. It is proposed that the main factors related to the formation of these trophic groups are the species convergence in the use of abundant food resources and variation in primary prey depending on the size of the predator, differences in microhabitat and trophic specialization of the species. The results of the canonical correlation analysis allowed relating the distribution of trophic groups in the tidepools with both the physicochemical conditions and the interaction between the availability of micro-habitats and the ecological relationships between the species. It is concluded that the trophic organization of the tidepool fish community of Praia dos Castelhanos is actually influenced by the environmental characteristics of the pools.

This study examined whether movements of fishes across reserve boundaries reduced the difference in density and size of fish between reserve and non-reserve areas. Visual censuses, experimental trapping, habitat measurements and tagging were performed at 10 sites on two nearly contiguous fringing coral reefs at the northern edge of the Barbados Marine Reserve and at 10 sites on the two fringing reefs closest to the boundary in the non-reserve. The visual censuses showed that overall density and size of fishes large enough to be caught in Antillean fish traps were higher on reserve reefs than on non-reserve reefs. The differences in density and size varied considerably among species and were not statistically significant for individual species. In contrast to a previous study, experimental trap catches were not higher in the reserve than in the non-reserve. Visual censuses, trap catches, and their ratio (trappability) were affected by habitat variables. Species mobility, estimated by the maximum distance between locations at which an individual was captured, corrected for the sampling effort at that distance, was highly variable among species (medians 0--116m). For the more mobile species, movements within fringing reefs and between the nearly contiguous reserve reefs was high but extremely rare among reefs separated by expanses of sand and rubble. For this discrete fringing reef system, there is no evidence that movement across the reserve boundary influences the relative density or size of fish between the reserve and non-reserve.

Differences in coral reef fish assemblages were investigated on six South African and one southern Mozambican reef under varying management regimes. All of the South African reefs fall within marine protected areas (MPA) but are zoned for differing types and intensities of human activity. Reefs where no human activities are allowed were termed Sanctuaries, while those on which restricted fishing and SCUBA diving are permitted were termed Protected. The reef in southern Mozambique is subjected to unrestricted fishing and SCUBA diving and was consequently termed Open. This study consists of two parts. The first dealt with a community assessment which investigated and provided baseline data on the trophic structure, density, and species diversity of fish assemblages on each of the seven study reefs. The objective was to compare the aforementioned metrics between reefs and thereafter compare them between the different protection zones. The second part of this study focused on assessing the impacts of human activities using 25 fish indicator species. These species were selected a priori based on their ecological importance and sensitivity to human activity (fishing and diving). The selection process was then guided by the results of the community assessment. The objective was to use these species as indicators of recreational diving and fishing pressure in the different protection zones. Density, biomass and size frequency analyses comprised the primary metrics in this assessment. Randomly stratified underwater visual censuses (UVC) were used to collect the fish data and these were conducted on reefs inhabited by a coral community considered to be the core community on South Africa’s reefs in terms of biodiversity and coral cover. The fish community assessment consisted of timed counts in which all non-cryptic fish species were quantified. Indicator species counts employed the point count technique with a radius of 10 m. An average of 11 community counts and an average of 62 point counts were conducted per reef. Various environmental variables and habitat characteritics were recorded during the UVCs. Multivariate analysis of the fish assemblages indicated that the fish community structure differed significantly according to reef protection status. Sanctuary reefs were significantly different from the Open reef in Southern Mozambique. Mean fish abundance was highest on Sanctuary reefs and lowest on the Open reef. In terms of overall species diversity, a total of 284 species belonging to 50 families were recorded, this being comparable to other reefs in the WIO region. Six families contributed more than 50% towards the fish community composition: Labridae, Acanthuridae, Chaetodontidae, Lutjanidae, Pomacentridae and Serranidae. All predator categories were well represented on Sanctuary reefs, while top-level predators were scarce on the High-Diving and the Open reef. Generalised linear model (GLM) regression analysis indicated that human activities were significant variables in accounting for the variance in fish community structure. The total fish abundance and biomass of the selected indicator species were significantly higher in Sanctuary zones and lowest in the Open zone. In addition, Sanctuary zones were characterised by high numbers of large predators, while non-Sanctuary zones were characterised by higher abundances of prey species. Target species were also larger and more abundant in Sanctuary zones. The data revealed that recreational fishing and high diving intensity may be influencing the fish community structure on southern African coral reefs, which was confirmed by GLM regression analysis. Long-term monitoring of these fish communities is recommended to confirm the trends observed in this data set. / Thesis (Ph.D.)-University of KwaZulu-Natal, Westville, 2010.

This study used trapping and visual census surveys to assess whether a marine reserve in Barbados effectively protected coral reef fish stocks and whether there was evidence of emigration from the reserve. Fish abundance and sizes were higher in the reserve than in surrounding non-reserve areas. Relative differences in abundance and size between reserve and non-reserve of different taxa were positively correlated to vulnerability to traps (the most common fishing method) but not to mobility of fish. Gradients of abundance across the reserve boundaries (decreasing abundance with distance from the reserve center) were apparent for total abundance but not for individual taxa. These patterns suggest that the reserve does protect fish stocks and that emigration is of minor importance.

Thesis (M.Sc.-Res.)--University of Wollongong, 2007. / Typescript. Includes bibliographical references: p. 69-83.

Thesis (M.A.)--West Virginia University, 2008. / Title from document title page. Document formatted into pages; contains vi, 36 p. : ill. (some col.), col. map. Includes abstract. Includes bibliographical references (p. 31-36).

Thesis (M.Sc. (Ichthyology & Fisheries Science)) - Rhodes University, 2008.