Search

Abstract Offshore oil and gas platforms support abundant reef fish and are popular fishing sites for recreational anglers. However, the rapid decommissioning and removal of active platforms have decreased such fishing opportunities in the Gulf of Mexico, raising concerns about fisheries impacts. Conversely, planned offshore energy structures like wind turbines may offer similar habitats and fishing sites. To inform spatial planning for marine energy infrastructure in the context of recreational fisheries, we created models of fish communities associated with oil and gas platforms using existing abundance data. We employed Random Forest analysis to predict the presence‐absence and abundance of Red Snapper (Lutjanus campechanus) and Greater Amberjack (Seriola dumerili) at platforms using 47 environmental and platform variables. Nonmetric multidimensional scaling on Bray−Curtis dissimilarities explored fish species composition among 37 species. Results showed variability in Red Snapper and Greater Amberjack incidence/abundance from shore to shelf‐edge, not attributed to surrounding habitat or climatological oceanographic variables. Incidence models were more robust than abundance models. Fish species composition was significantly influenced by location gradient, with less impact from other habitat features. Our findings guide selecting areas for artificial structures to enhance angler opportunities and maintain fish diversity, but identifying the drivers of finer scale abundance variation will require further sampling.

Abstract Climate change is causing shifts in the geographic distributions of coastal fish species toward higher latitudes. However, local fish communities found in higher latitudes today are not simply those found in lower latitudes in the past because the sensitivity of species to various environmental conditions is different. Responses of fish to environmental conditions differ depending on their life‐history traits such as the maximum population growth rate, age of maturity, and generation time because these traits are constrained by environmental conditions. Here, we investigate associations among temporal patterns in presence–absence (incidence) data, life‐history traits of species, and environmental conditions to elucidate the potential mechanisms behind the effects of climate change on coastal fish communities. In this study, fish monitoring data collected semi‐monthly between 1982 and 2019 from eight major bays in the northwestern Gulf of Mexico were analyzed with generalized additive models. Smooth patterns over seasons and years in the incidence data of 77 species were estimated, and the data were associated with environmental variables. Further, these temporal patterns were associated with the life‐history traits of species. The results show that species that are more common in the summer months (non‐winter spawners) tend to exhibit an increasing trend and that species common during the spring (winter spawners) tend to exhibit a decreasing trend, suggesting the importance of summer conditions in driving tropicalization. Salinity had significant effects on species in general, and longer‐lived species tended to be affected by temperature. These results suggest seasonal differences in the effects of environmental conditions and variation in sensitivity to environmental conditions among different life‐history strategies. These findings represent major steps toward understanding the mechanisms behind the tropicalization of estuarine communities.

Abstract Habitat alterations that result from anthropogenic disturbance impact both the abiotic and biotic conditions of ecosystems, causing changes in biodiversity in many parts of the world. Recently, the use of functional diversity has been suggested as an approach to better evaluate the effects of such disturbance on particular communities. Here, we investigated the temporal changes in species and functional diversities of fish communities in the downstream area of the Three Gorges Dam (TGD) before, during, and after impoundment. We found two regime shifts in the fish community in 2004 and 2013 following impoundment. Although taxonomic diversity declined sharply at the first regime shift, it increased at the second shift. On the other hand, functional diversity declined throughout the same period, indicating the loss of functional diversity despite increased species diversity. Our analysis also showed that the fish communities shifted from under‐dispersion to over‐dispersion due to both a decrease in the relative abundance of migratory fish and an increase in the number of fish adapted to the new hydrologic conditions. Our results indicated that the impacts of dams on downstream fish communities may change over time. Interactions between species may become more important when the environment is stable.

Abstract Climate change causes marine species to shift and expand their distributions, often leading to changes in species diversity. While increased biodiversity is often assumed to confer positive benefits on ecosystem functioning, many examples have shown that the relationship is specific to the ecosystem and function studied and is often driven by functional composition and diversity. In the northwestern Gulf of Mexico, tropical species expansion was shown to have increased estuarine fish and invertebrate diversity; however, it is not yet known how those increases have affected functional diversity. To address this knowledge gap, two metrics of functional diversity, functional richness (FRic) and functional dispersion (FDis), were estimated in each year for a 38‐year study period, for each of the eight major bays along the Texas coast. Then, the community‐weighted mean (CWM) trait values for each of the functional traits are calculated to assess how functional composition has changed through time. Finally, principal component analysis (PCA) was used to identify species contributing most to changing functional diversity. We found significant increases in log‐functional richness in both spring and fall, and significant decreases in functional dispersion in spring, suggesting that although new functional types are entering the bays, assemblages are becoming more dominated by similar functional types. Community‐weighted trait means showed significant increases in the relative abundance of traits associated with large, long‐lived, higher trophic level species, suggesting an increase in periodic and equilibrium life‐history strategists within the bays. PCA identified mainly native sciaenid species as contributing most to functional diversity trends although several tropical species also show increasing trends through time. We conclude that the climate‐driven species expansion in the northwestern Gulf of Mexico led to a decrease in functional dispersion due to increasing relative abundance of species with similar life‐history characteristics, and thus the communities have become more functionally homogeneous.

Introduction In the mid‐1990s, Cambodia faced one of the fastest growing HIV epidemics in Asia. For its achievement in reversing this trend, and achieving universal access to HIV treatment, the country received a United Nations millennium development goal award in 2010. This article reviews Cambodia’s response to HIV over the past two decades and discusses its current efforts towards elimination of new HIV infections. Methods A literature review of published and unpublished documents, including programme data and presentations, was conducted. Results and discussion Cambodia classifies its response to one of the most serious HIV epidemics in Asia into three phases. In Phase I (1991–2000), when adult HIV prevalence peaked at 1.7% and incidence exceeded 20,000 cases, a nationwide HIV prevention programme targeted brothel‐based sex work. Voluntary confidential counselling and testing and home‐based care were introduced, and peer support groups of people living with HIV emerged. Phase II (2001–2011) observed a steady decline in adult prevalence to 0.8% and incidence to 1600 cases by 2011, and was characterized by: expanding antiretroviral treatment (coverage reaching more than 80%) and continuum of care; linking with tuberculosis and maternal and child health services; accelerated prevention among key populations, including entertainment establishment‐based sex workers, men having sex with men, transgender persons, and people who inject drugs; engagement of health workers to deliver quality services; and strengthening health service delivery systems. The third phase (2012–2020) aims to attain zero new infections by 2020 through: sharpening responses to key populations at higher risk; maximizing access to community and facility‐based testing and retention in prevention and care; and accelerating the transition from vertical approaches to linked/integrated approaches. Conclusions Cambodia has tailored its prevention strategy to its own epidemic, established systematic linkages across different services and communities, and achieved nearly universal coverage of HIV services nationwide. Still, the programme must continually (re)prioritize the most effective and efficient interventions, strengthen synergies between programmes, contribute to health system strengthening, and increase domestic funding so that the gains of the previous two decades are sustained, and the goal of zero new infections is reached.

Introduction In the mid‐1990s, Cambodia faced one of the fastest growing HIV epidemics in Asia. For its achievement in reversing this trend, and achieving universal access to HIV treatment, the country received a United Nations millennium development goal award in 2010. This article reviews Cambodia’s response to HIV over the past two decades and discusses its current efforts towards elimination of new HIV infections. Methods A literature review of published and unpublished documents, including programme data and presentations, was conducted. Results and discussion Cambodia classifies its response to one of the most serious HIV epidemics in Asia into three phases. In Phase I (1991–2000), when adult HIV prevalence peaked at 1.7% and incidence exceeded 20,000 cases, a nationwide HIV prevention programme targeted brothel‐based sex work. Voluntary confidential counselling and testing and home‐based care were introduced, and peer support groups of people living with HIV emerged. Phase II (2001–2011) observed a steady decline in adult prevalence to 0.8% and incidence to 1600 cases by 2011, and was characterized by: expanding antiretroviral treatment (coverage reaching more than 80%) and continuum of care; linking with tuberculosis and maternal and child health services; accelerated prevention among key populations, including entertainment establishment‐based sex workers, men having sex with men, transgender persons, and people who inject drugs; engagement of health workers to deliver quality services; and strengthening health service delivery systems. The third phase (2012–2020) aims to attain zero new infections by 2020 through: sharpening responses to key populations at higher risk; maximizing access to community and facility‐based testing and retention in prevention and care; and accelerating the transition from vertical approaches to linked/integrated approaches. Conclusions Cambodia has tailored its prevention strategy to its own epidemic, established systematic linkages across different services and communities, and achieved nearly universal coverage of HIV services nationwide. Still, the programme must continually (re)prioritize the most effective and efficient interventions, strengthen synergies between programmes, contribute to health system strengthening, and increase domestic funding so that the gains of the previous two decades are sustained, and the goal of zero new infections is reached.