Effects of habitat on the recruitment variation of coral reef fishes.

Coral reef fish life cycles have two distinct phases that take place in different parts of their environment. Benthonic or pelagic eggs spawned by adults hatch into larvae that join the water column, after spending some variable time in it they settle back on to a reef. It is well documented that recruitment is highly variable across space and time. This variation can be a reflection of factor occurring during the pelagic larval phase, or during the settlement event. Prior to settlement the number of larvae settling to a given location could be a consequence of oceanographic features, as well as random events taking place during the pelagic larval phase which might affect the survival of larvae. Larvae then have been found to settle differentially to a preferred habitat. These associations have been studied at several spatial scales with contrasting results. In order to explore relationships between habitat and patterns of recruitment, we must first describe the habitat features found at a given location. Chapter two explored the effects that sampling intensity (i.e. number of sampling points or quadrats) and method (point-intercept vs. photo quadrats) have on the comprehensiveness and precision of percent cover estimates of substratum abundances. Chapter three assessed the degree to which habitat type can explain the spatial and temporal variation observed in the recruitment of 2 coral reef species. (Abstract shortened by UMI.)Dept. of Biological Sciences. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis2004 .U87. Source: Masters Abstracts International, Volume: 43-01, page: 0150. Adviser: Peter F. Sale. Thesis (M.Sc.)--University of Windsor (Canada), 2004

Global human footprint on the linkage between biodiversity and ecosystem functioning in reef fishes

Copyright: © 2011 Mora et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.Difficulties in scaling up theoretical and experimental results have raised controversy over the consequences of biodiversity loss for the functioning of natural ecosystems. Using a global survey of reef fish assemblages, we show that in contrast to previous theoretical and experimental studies, ecosystem functioning (as measured by standing biomass) scales in a non-saturating manner with biodiversity (as measured by species and functional richness) in this ecosystem. Our field study also shows a significant and negative interaction between human population density and biodiversity on ecosystem functioning (i.e., for the same human density there were larger reductions in standing biomass at more diverse reefs). Human effects were found to be related to fishing, coastal development, and land use stressors, and currently affect over 75% of the world's coral reefs. Our results indicate that the consequences of biodiversity loss in coral reefs have been considerably underestimated based on existing knowledge and that reef fish assemblages, particularly the most diverse, are greatly vulnerable to the expansion and intensity of anthropogenic stressors in coastal areas

Biotic and Human Vulnerability to Projected Changes in Ocean Biogeochemistry over the 21st Century

Ongoing greenhouse gas emissions can modify climate processes and induce shifts in ocean temperature, pH, oxygen concentration, and productivity, which in turn could alter biological and social systems. Here, we provide a synoptic global assessment of the simultaneous changes in future ocean biogeochemical variables over marine biota and their broader implications for people. We analyzed modern Earth System Models forced by greenhouse gas concentration pathways until 2100 and showed that the entire world's ocean surface will be simultaneously impacted by varying intensities of ocean warming, acidification, oxygen depletion, or shortfalls in productivity. In contrast, only a small fraction of the world's ocean surface, mostly in polar regions, will experience increased oxygenation and productivity, while almost nowhere will there be ocean cooling or pH elevation. We compiled the global distribution of 32 marine habitats and biodiversity hotspots and found that they would all experience simultaneous exposure to changes in multiple biogeochemical variables. This superposition highlights the high risk for synergistic ecosystem responses, the suite of physiological adaptations needed to cope with future climate change, and the potential for reorganization of global biodiversity patterns. If co-occurring biogeochemical changes influence the delivery of ocean goods and services, then they could also have a considerable effect on human welfare. Approximately 470 to 870 million of the poorest people in the world rely heavily on the ocean for food, jobs, and revenues and live in countries that will be most affected by simultaneous changes in ocean biogeochemistry. These results highlight the high risk of degradation of marine ecosystems and associated human hardship expected in a future following current trends in anthropogenic greenhouse gas emissions

The Galapagos Grouper Fishery: Mostly Dead, Stunned, or In Need of Management Regulations?

Ph.D. University of Hawaii at Manoa 2015.Includes bibliographical references.The Galapagos sailfin grouper Mycteroperca olfax, locally known as bacalao, is an important ecological, cultural, and economical resource in the Galapagos Archipelago. However, years of intensive fishing pressure have resulted clear signs of overfishing. Bacalao represent an important resource for which there is no management, but for which management cannot be implemented because of a lack of information on the current status of the fishery and inconsistencies in life history information. My research was, therefore, aimed at assessing life history and fisheries attributes for bacalao with the goal of providing management options for this species. Longevity of bacalao is greater than previously reported, with a maximum recorded age of 21 years. Growth estimates showed bacalao to grow larger and slower than previously thought. Size at maturity was also estimated to be larger than previously accepted assessments. Current status of the bacalao fishery is worrisome as it is undergoing both recruitment and growth overfishing. The percentage of fish above size at maturity in the catch has dropped to an all time low, and Spawning Potential Ratio suggests that bacalao is facing imminent reproductive failure. Furthermore, over a 20-­‐‑year period there have been declines in all of the stock health indicators, with 2012 being the lowest year on record. In lieu of management regulations specifically aimed at bacalao, the Galapagos Marine Reserve relies on no-­‐‑take zones to provide protection from fishing. However, size of bacalao, catch rates, and catch composition were indistinguishable between areas open and closed to fishing. Bacalao showed high site fidelity and likely do not move outside no-­‐‑take zones, and therefore poaching within these zones may contribute to the patterns observed. An evaluation of the knowledge of fishers of the current GMR zonation suggests that this lack of compliance due to unwitting poaching. My research has provided valuable information upon which management regulations for bacalao can be built, these should include slot limits, temporal closures, and adequate enforcement of no fishing areas

Rapport III.12. DEDALE, un système de modélisation pour la gestion des aquifères côtiers

Usseglio Polatera Jean-Marc, Jardin Paul, Molinaro Paolo. Rapport III.12. DEDALE, un système de modélisation pour la gestion des aquifères côtiers. In: Les eaux souterraines et la gestion des eaux. Progrès - qualité - quantité. Vingt et unièmes journées de l'hydraulique. Sophia-Antipolis, 29-31 janvier1991. Tome 3, 1991

Effectiveness of removals of the invasive lionfish: how many dives are needed to deplete a reef?

Introduced Indo-Pacific red lionfish (Pterois volitans/miles) have spread throughout the greater Caribbean and are associated with a number of negative impacts on reef ecosystems. Human interventions, in the form of culling activities, are becoming common to reduce their numbers and mitigate the negative effects associated with the invasion. However, marine managers must often decide how to best allocate limited resources. Previous work has identified the population size thresholds needed to limit the negative impacts of lionfish. Here we develop a framework that allows managers to predict the removal effort required to achieve specific targets (represented as the percent of lionfish remaining on the reef). We found an important trade-off between time spent removing and achieving an increasingly smaller lionfish density. The model used in our suggested framework requires relatively little data to parameterize, allowing its use with already existing data, permitting managers to tailor their culling strategy to maximize efficiency and rate of success

Water Currents and Water Budget in a Coastal Megastructure, Palm Jumeirah Lagoon, Dubai, UAE

Palm Jumeirah is the most completely developed of several man-made coastal island megaconstructions in Dubai, United Arab Emirates. The palm-shaped island, surrounded by an elliptical breakwater, was developed 7 y ago, has an overall footprint of 23 km2, of which the constructed island surface area is 7.9 km2, and is connected to shore via a 5-km-long spine from the mainland to the crescent tip. Time-series observations of hydrographic variables and currents within the interior of the development (Palm Jumeirah Lagoon) during 30 d in April–May 2008 were utilized to examine current flow, tide variability, water budget, vertical mixing, and turnover time within this megastructure. Currents within Palm Jumeirah Lagoon varied between stations; however, similar water temperatures and salinities were apparent throughout all the stations. Palm Jumeirah Lagoon tides were mixed and mainly semidiurnal, with spring and neap tidal ranges measuring 116 and 56 cm, respectively, and no difference in amplitude or phase throughout Palm Jumeirah Lagoon. There were substantial differences in water discharge between the east and west entrances, with high discharge on average exiting the eastern entrance and low discharge exiting the western entrance. These results indicate that the eastern and western halves of Palm Jumeirah Lagoon are flushed unequally and show differences in residence times (1.2 and 42 d, respectively), due to differences in tidal currents, wind influence, and variability of the bathymetric contour. Previous numerical modeling studies of water residence time within Palm Jumeirah Lagoon did not capture this difference, which could be associated with the exclusion of bathymetric variability in the previous modeling. Due to the strong shear and weak saline stratification, the water column throughout Palm Jumeirah Lagoon remained instable, with vertical mixing present during the spring-neap tidal cycle and well-mixed conditions predominating throughout the lagoon system

Tropical harmful algal blooms: an emerging threat to coral reef communities?

Tropical harmful algal blooms (HABs) are increasing in frequency and intensity and are substantially affecting marine communities. In October/November 2008 a large-scale HAB event (> 500 km2, dinoflagellate Cochlodinium polykrikoides) in the Gulf of Oman caused the complete loss of the branching corals, Pocillopora and Acropora spp., and substantial reductions in the abundance, richness and trophic diversity of the associated coral reef fish communities. Although the causative agents of this C. polykrikoides bloom are unknown, increased coastal enrichment, natural oceanographic mechanisms, and the recent expansion of this species within ballast water discharge are expected to be the main agents. With rapid changes in oceanic climate, enhanced coastal eutrophication and increased global distribution of HAB species within ballast water, large-scale HAB events are predicted to increase dramatically in both intensity and distribution and can be expected to have increasingly negative effects on coral reef communities globally