Evidence of population-level impacts and resiliency for Gulf of Mexico shelf taxa following the Deepwater Horizon oil spill

The goal of this paper was to review the evidence of population-level impacts of the Deepwater Horizon Oil Spill (DWH) on Gulf of Mexico (GOM) continental shelf taxa, as well as evidence of resiliency following the DWH. There is considerable environmental and biological evidence that GOM shelf taxa were exposed to and suffered direct and indirect impacts of the DWH. Numerous assessments, from mesocosm studies to analysis of biopsied tissue or tissue samples from necropsied animals, revealed a constellation of physiological effects related to DWH impacts on GOM biota, some of which clearly or likely resulted in mortality. While the estimated concentrations of hydrocarbons in shelf waters and sediments were orders of magnitude lower than measured in inshore or deep GOM environments, the level of mortality observed or predicted was substantial for many shelf taxa. In some cases, such as for zooplankton, community shifts following the spill were ephemeral, likely reflecting high rates of population turnover and productivity. In other taxa, such as GOM reef fishes, impacts of the spill are confounded with other stressors, such as fishing mortality or the appearance and rapid population growth of invasive lionfish (Pterois spp.). In yet others, such as cetaceans, modeling efforts to predict population-level effects of the DWH made conservative assumptions given the species’ protected status, which post-DWH population assessments either failed to detect or population increases were estimated. A persistent theme that emerged was the lack of precise population-level data or assessments prior to the DWH for many taxa, but even when data or assessments did exist, examining evidence of population resiliency was confounded by other stressors impacting GOM biota. Unless efforts are made to increase the resolution of the data or precision of population assessments, difficulties will likely remain in estimating the scale of population-level effects or resiliency in the case of future large-scale environmental catastrophes

Distribution and Habitat Associations of Billfish and Swordfish Larvae across Mesoscale Features in the Gulf of Mexico

Ichthyoplankton surveys were conducted in surface waters of the northern Gulf of Mexico (NGoM) over a three-year period (2006–2008) to determine the relative value of this region as early life habitat of sailfish (Istiophorus platypterus), blue marlin (Makaira nigricans), white marlin (Kajikia albida), and swordfish (Xiphias gladius). Sailfish were the dominant billfish collected in summer surveys, and larvae were present at 37.5% of the stations sampled. Blue marlin and white marlin larvae were present at 25.0% and 4.6% of the stations sampled, respectively, while swordfish occurred at 17.2% of the stations. Areas of peak production were detected and maximum density estimates for sailfish (22.09 larvae 1000 m−2) were significantly higher than the three other species: blue marlin (9.62 larvae 1000 m−2), white marlin (5.44 larvae 1000 m−2), and swordfish (4.67 larvae 1000 m−2). The distribution and abundance of billfish and swordfish larvae varied spatially and temporally, and several environmental variables (sea surface temperature, salinity, sea surface height, distance to the Loop Current, current velocity, water depth, and Sargassum biomass) were deemed to be influential variables in generalized additive models (GAMs). Mesoscale features in the NGoM affected the distribution and abundance of billfish and swordfish larvae, with densities typically higher in frontal zones or areas proximal to the Loop Current. Habitat suitability of all four species was strongly linked to physicochemical attributes of the water masses they inhabited, and observed abundance was higher in slope waters with lower sea surface temperature and higher salinity. Our results highlight the value of the NGoM as early life habitat of billfishes and swordfish, and represent valuable baseline data for evaluating anthropogenic effects (i.e., Deepwater Horizon oil spill) on the Atlantic billfish and swordfish populations

Relationships between blooms of Karenia brevis and hypoxia across the West Florida Shelf

Harmful algal blooms (HABs) caused by the dinoflagellate Karenia brevis on the West Florida Shelf have become a nearly annual occurrence causing widespread ecological and economic harm. Effects range from minor respiratory irritation and localized fish kills to large-scale and long-term events causing massive mortalities to marine organisms. Reports of hypoxia on the shelf have been infrequent; however, there have been some indications that some HABs have been associated with localized hypoxia. We examined oceanographic data from 2004 to 2019 across the West Florida Shelf to determine the frequency of hypoxia and to assess its association with known HABs. Hypoxia was present in 5 of the 16 years examined and was always found shoreward of the 50-meter bathymetry line. There were 2 clusters of recurrent hypoxia: midshelf off the Big Bend coast and near the southwest Florida coast. We identified 3 hypoxic events that were characterized by multiple conductivity, temperature, and depth (CTD) casts and occurred concurrently with extreme HABs in 2005, 2014, and 2018. These HAB-hypoxia events occurred when K. brevis blooms initiated in early summer months and persisted into the fall likely driven by increased biological oxygen demand from decaying algal biomass and reduced water column ventilation due to stratification. There were also four years, 2011, 2013, 2015, and 2017, with low dissolved oxygen located near the shelf break that were likely associated with upwelling of deeper Gulf of Mexico water onto the shelf. We had difficulty in assessing the spatiotemporal extent of these events due to limited data availability and potentially unobserved hypoxia due to the inconsistent difference between the bottom of the CTD cast and the seafloor. While we cannot unequivocally explain the association between extreme HABs and hypoxia on the West Florida Shelf, there is sufficient evidence to suggest a causal linkage between them

Late‐life living and care arrangements of older Filipino NewZealanders

Aims and objectives: To explore the living and care arrangement plans of older Filipino immigrants in New Zealand. Background: New Zealand is rapidly becoming the host to an increasing number of ageing Filipino immigrants. Despite this sizeable population growth of ageing Filipinos in New Zealand, still very little is known about this ethnic group\u27s care needs and living arrangement preferences in later life within the New Zealand context. Design: Qualitative descriptive approach. Methods: Data were collected from 15 older Filipinos who participated in face‐to-face interviews. Data were analysed using a thematic analytical framework. Results: Two major themes were identified from the data analysis. The first theme “preferred living and care arrangements” is about older Filipinos’ preferred plans for future residence and in receiving care when no longer able to function independently in their own homes. The second theme “negotiating readiness and acceptance” is about hypothetical situations that older Filipinos described and anticipated that will greatly facilitate their readiness and acceptance to living in aged care facilities. Conclusion: The study results have implications for service delivery within the New Zealand residential aged care sector. Due to an increasing number of older Filipino immigrants requiring care, residential aged care facilities must ensure their care models meet the needs of this growing group of older people. Relevance to clinical practice: Nursing staff skill sets in the aged care sector require sensitivity to older immigrants’ health needs without compromising cultural beliefs and practices while living in residential aged care facilities

Distribution of angel sharks (Squatinidae) in United States waters of the western North Atlantic Ocean

The distributions of sharks inhabiting Deepwater ecosystems (>200 m) remain largely speculative because of limited collection efforts for species of relatively low commercial value and because of difficulties associated with sampling in Deepwater habitats. As a result, ranges of Deepwater shark species are often considered continuous across broad expanses despite records of occurrence, in many cases, being spatially fragmented. Within United States (US) waters of the western North Atlantic Ocean (WNA), the range of angel sharks (Squatinidae) in continental shelf and slope waters has been variously reported as both continuous and disjunct. The objective of this study was to use fishery-independent data to describe the range of angel sharks in US waters of the WNA and identify potential spatial discontinuities that could be consistent with the idea of multiple species or populations in the region. Results indicate that angel sharks in US waters of the WNA have a disjunct distribution and discontinuities occur from approximately Georgia through southern Florida and within a well-defined area off the coast of Louisiana. Evidence suggests spatial discontinuities could be related to thermal, salinity or current velocity barriers, or to a combination of these factors

Reducing Vibration Of Reciprocating Engines With Crankshaft Pendulum Vibration Absorbers

Four-cylinder in-line automobile engines are inexpensive to build and economical to operate. However, they produce high crankshaft torsional vibration and high engine block vibration. Traditional ways to reduce this vibration may harm driveability and fuel economy, and may increase the cost of construction. Crankshaft-mounted pendulums have the potential to simultaneously reduce crankshaft torsional vibration and block shake at a reasonable cost without affecting driveability and fuel economy. Described in this paper is a study of the feasibility of applying pendulums to modern four-cylinder engines. The study involved the design, construction and testing of hardware, and an extensive analysis effort. Explored by analysis were optimal trajectories for pendulum motion, strategies for tuning sets of pendulums, the stability of pendulum motion and the shaking behavior of engines equipped with pendulums. Established by both analysis and test was that crank-shaft-mounted pendulums can reduce torsional vibration by over 90%. Vehicle test established that there were subjective improvements in NVH (Noise, Vibration and Harshness) and further that lugging performance - low speed, wide open throttle performance - was dramatically improved. The reduction in block shake observed during test was more modest than the reduction of torsion. Analytical studies of shake performance produced predictions of reductions in the range of 40% to over 70% for realistic pendulum damping and for realistic configurations. Shown by the study is the feasibility of crankshaft-mounted pendulums for reducing torsional vibration in modern four-cylinder automotive engines. Also shown is that crankshaft-mounted pendulums is a promising technology for reducing shake in four-cylinder engines. Copyright © 1991 Society of Automotive Engineers, Inc

Monitoring Programs of the U.S. Gulf of Mexico: Inventory, Development and Use of a Large Monitoring Database to Map Fish and Invertebrate Spatial Distributions

Since the onset of fisheries science, monitoring programs have been implemented to support stock assessments and fisheries management. Here, we take inventory of the monitoring programs of the U.S. Gulf of Mexico (GOM) surveying fish and invertebrates and conduct a gap analysis of these programs. We also compile a large monitoring database encompassing much of the monitoring data collected in the U.S. GOM using random sampling schemes and employ this database to fit statistical models to then map the spatial distributions of 61 fish and invertebrate functional groups, species and life stages of the U.S. GOM. Finally, we provide recommendations for improving current monitoring programs and designing new programs, and guidance for more comprehensive use and sharing of monitoring data, with the ultimate goal of enhancing the inputs provided to stock assessments and ecosystem-based fisheries management (EBFM) projects in the U.S. GOM. Our inventory revealed that 73 fisheries-independent and fisheries-dependent programs have been conducted in the U.S. GOM, most of which (85%) are still active. One distinctive feature of monitoring programs of the U.S. GOM is that they include many fisheries-independent surveys conducted almost year-round, contrasting with most other marine regions. A major sampling recommendation is the development of a coordinated strategy for collecting diet information by existing U.S. GOM monitoring programs for advancing EBFM

An Analysis of Artificial Reef Fish Community Structure along the Northwestern Gulf of Mexico Shelf: Potential Impacts of “Rigs-to-Reefs” Programs

Artificial structures are the dominant complex marine habitat type along the northwestern Gulf of Mexico (GOM) shelf. These habitats can consist of a variety of materials, but in this region are primarily comprised of active and reefed oil and gas platforms. Despite being established for several decades, the fish communities inhabiting these structures remain poorly investigated. Between 2012 and 2013 we assessed fish communities at 15 sites using remotely operated vehicles (ROVs). Fish assemblages were quantified from standing platforms and an array of artificial reef types (Liberty Ships and partially removed or toppled platforms) distributed over the Texas continental shelf. The depth gradient covered by the surveys (30-84 m) and variability in structure density and relief also permitted analyses of the effects of these characteristics on fish richness, diversity, and assemblage composition. ROVs captured a variety of species inhabiting these reefs from large transient piscivores to small herbivorous reef fishes. While structure type and relief were shown to influence species richness and community structure, major trends in species composition were largely explained by the bottom depth where these structures occurred. We observed a shift in fish communities and relatively high diversity at approximately 60 m bottom depth, confirming trends observed in previous studies of standing platforms. This depth was also correlated with some of the largest Red Snapper captured on supplementary vertical longline surveys. Our work indicates that managers of artificial reefing programs (e.g., Rigs-to-Reefs) in the GOM should carefully consider the ambient environmental conditions when designing reef sites. For the Texas continental shelf, reefing materials at a 50-60 m bottom depth can serve a dual purpose of enhancing diving experiences and providing the best potential habitat for relatively large Red Snapper