NOAA National Marine Fisheries Service Southeast Regional Office

A northern Gulf of Mexico (GoM) cetacean unusual mortality event (UME) involving primarily bottlenose dolphins (Tursiops truncatus) in Louisiana, Mississippi, and Alabama began in February 2010 and continued into 2014. Overlapping in time and space with this UME was the Deepwater Horizon (DWH) oil spill, which was proposed as a contributing cause of adrenal disease, lung disease, and poor health in live dolphins examined during 2011 in Barataria Bay, Louisiana. To assess potential contributing factors and causes of deaths for stranded UME dolphins from June 2010 through December 2012, lung and adrenal gland tissues were histologically evaluated from 46 fresh dead non-perinatal carcasses that stranded in Louisiana (including 22 from Barataria Bay), Mississippi, and Alabama. UME dolphins were tested for evidence of biotoxicosis, morbillivirus infection, and brucellosis. Results were compared to up to 106 fresh dead stranded dolphins from outside the UME area or prior to the DWH spill. UME dolphins were more likely to have primary bacterial pneumonia (22% compared to 2% in non-UME dolphins, P = .003) and thin adrenal cortices (33% compared to 7% in non-UME dolphins, P = .003). In 70% of UME dolphins with primary bacterial pneumonia, the condition either caused or contributed significantly to death. Brucellosis and morbillivirus infections were detected in 7% and 11% of UME dolphins, respectively, and biotoxin levels were low or below the detection limit, indicating that these were not primary causes of the current UME. The rare, life-threatening, and chronic adrenal gland and lung diseases identified in stranded UME dolphins are consistent with exposure to petroleum compounds as seen in other mammals. Exposure of dolphins to elevated petroleum compounds present in coastal GoM waters during and after the DWH oil spill is proposed as a cause of adrenal and lung disease and as a contributor to increased dolphin deaths.

In the United States, implementation of strong legislative mandates and investments in scientific programmes have supported sustainable fisheries management for seafood production, marine ecosystems, and maritime communities and economies. Changing climate and ocean conditions present new and growing challenges that affect the ability to manage fisheries. To better prepare for and respond to these

Abstract To determine effectiveness of Seasonal Management Areas (SMAs), introduced in 2008 on the U.S. East Coast to reduce lethal vessel strikes to North Atlantic right whales, we analyzed observed large whale mortality events from 1990–2012 in the geographic region of the “Ship Strike Rule” to identify changes in frequency, spatial distribution, and spatiotemporal interaction since implementation. Though not directly coincident with SMA implementation, right whale vessel‐strike mortalities significantly declined from 2.0 (2000–2006) to 0.33 per year (2007–2012). Large whale vessel‐strike mortalities have decreased inside active SMAs, and increased outside inactive SMAs. We detected no significant spatiotemporal interaction in the 4‐year pre‐ or post‐Rule periods, although a longer time series is needed to detect these changes. As designed, SMAs encompass only 36% of historical right whale vessel‐strike mortalities, and 32% are outside managed space but within managed timeframes. We suggest increasing spatial coverage to improve the Rule's effectiveness.

The rapid loss of reef-building corals owing to ocean warming is driving the development of interventions such as coral propagation and restoration, selective breeding and assisted gene flow. Many of these interventions target naturally heat-tolerant individuals to boost climate resilience, but the challenges of quickly and reliably quantifying heat tolerance and identifying thermotolerant individuals have hampered implementation. Here, we used coral bleaching automated stress systems to perform rapid, standardized heat tolerance assays on 229 colonies of Acropora cervicornis across six coral nurseries spanning Florida's Coral Reef, USA. Analysis of heat stress dose–response curves for each colony revealed a broad range in thermal tolerance among individuals (approx. 2.5°C range in F v /F m ED50), with highly reproducible rankings across independent tests ( r = 0.76). Most phenotypic variation occurred within nurseries rather than between them, pointing to a potentially dominant role of fixed genetic effects in setting thermal tolerance and widespread distribution of tolerant individuals throughout the population. The identification of tolerant individuals provides immediately actionable information to optimize nursery and restoration programmes for Florida's threatened staghorn corals. This work further provides a blueprint for future efforts to identify and source thermally tolerant corals for conservation interventions worldwide.

A multi-year unusual mortality event (UME) involving primarily common bottlenose dolphins (Tursiops truncates) was declared in the northern Gulf of Mexico (GoM) with an initial start date of February 2010 and remains ongoing as of August 2014. To examine potential changing characteristics of the UME over time, we compared the number and demographics of dolphin strandings from January 2010 through June 2013 across the entire GoM as well as against baseline (1990-2009) GoM stranding patterns. Years 2010 and 2011 had the highest annual number of stranded dolphins since Louisiana's record began, and 2011 was one of the years with the highest strandings for both Mississippi and Alabama. Statewide, annual numbers of stranded dolphins were not elevated for GoM coasts of Florida or Texas during the UME period. Demographic, spatial, and temporal clusters identified within this UME included increased strandings in northern coastal Louisiana and Mississippi (March-May 2010); Barataria Bay, Louisiana (August 2010-December 2011); Mississippi and Alabama (2011, including a high prevalence and number of stranded perinates); and multiple GoM states during early 2013. While the causes of the GoM UME have not been determined, the location and magnitude of dolphin strandings during and the year following the 2010 Deepwater Horizon oil spill, including the Barataria Bay cluster from August 2010 to December 2011, overlap in time and space with locations that received heavy and prolonged oiling. There are, however, multiple known causes of previous GoM dolphin UMEs, including brevetoxicosis and dolphin morbillivirus. Additionally, increased dolphin strandings occurred in northern Louisiana and Mississippi before the Deepwater Horizon oil spill. Identification of spatial, temporal, and demographic clusters within the UME suggest that this mortality event may involve different contributing factors varying by location, time, and bottlenose dolphin populations that will be better discerned by incorporating diagnostic information, including histopathology.

Abstract Multispecies models have existed in a fisheries context since at least the 1970s, but despite much exploration, advancement, and consideration of multispecies models, there remain limited examples of their operational use in fishery management. Given that species and fleet interactions are inherently multispecies problems and the push towards ecosystem-based fisheries management, the lack of more regular operational use is both surprising and compelling. We identify impediments hampering the regular operational use of multispecies models and provide recommendations to address those impediments. These recommendations are: (1) engage stakeholders and managers early and often; (2) improve messaging and communication about the various uses of multispecies models; (3) move forward with multispecies management under current authorities while exploring more inclusive governance structures and flexible decision-making frameworks for handling tradeoffs; (4) evaluate when a multispecies modelling approach may be more appropriate; (5) tailor the multispecies model to a clearly defined purpose; (6) develop interdisciplinary solutions to promoting multispecies model applications; (7) make guidelines available for multispecies model review and application; and (8) ensure code and models are well documented and reproducible. These recommendations draw from a global assemblage of subject matter experts who participated in a workshop entitled “Multispecies Modeling Applications in Fisheries Management”.

Managed reef fish in the Atlantic Ocean of the southeastern United States (SEUS) support a multi-billion dollar industry. There is a broad interest in locating and protecting spawning fish from harvest, to enhance productivity and reduce the potential for overfishing. We assessed spatiotemporal cues for spawning for six species from four reef fish families, using data on individual spawning condition collected by over three decades of regional fishery-independent reef fish surveys, combined with a series of predictors derived from bathymetric features. We quantified the size of spawning areas used by reef fish across many years and identified several multispecies spawning locations. We quantitatively identified cues for peak spawning and generated predictive maps for Gray Triggerfish (Balistes capriscus), White Grunt (Haemulon plumierii), Red Snapper (Lutjanus campechanus), Vermilion Snapper (Rhomboplites aurorubens), Black Sea Bass (Centropristis striata), and Scamp (Mycteroperca phenax). For example, Red Snapper peak spawning was predicted in 24.7-29.0°C water prior to the new moon at locations with high curvature in the 24-30 m depth range off northeast Florida during June and July. External validation using scientific and fishery-dependent data collections strongly supported the predictive utility of our models. We identified locations where reconfiguration or expansion of existing marine protected areas would protect spawning reef fish. We recommend increased sampling off southern Florida (south of 27° N), during winter months, and in high-relief, high current habitats to improve our understanding of timing and location of reef fish spawning off the southeastern United States.

Abstract Green sturgeon Acipenser medirostris spend much of their lives outside of their natal rivers, but the details of their migrations and habitat use are poorly known, which limits our understanding of how this species might be affected by human activities and habitat degradation. We tagged 355 green sturgeon with acoustic transmitters on their spawning grounds and in known nonspawning aggregation sites and examined their movement among these sites and other potentially important locations using automated data‐logging hydrophones. We found that green sturgeon inhabit a number of estuarine and coastal sites over the summer, including the Columbia River estuary, Willapa Bay, Grays Harbor, and the estuaries of certain smaller rivers in Oregon, especially the Umpqua River estuary. Green sturgeon from different natal rivers exhibited different patterns of habitat use; most notably, San Francisco Bay was used only by Sacramento River fish, while the Umpqua River estuary was used mostly by fish from the Klamath and Rogue rivers. Earlier work, based on analysis of microsatellite markers, suggested that the Columbia River mixed stock was mainly composed of fish from the Sacramento River, but our results indicate that fish from the Rogue and Klamath River populations frequently use the Columbia River as well. We also found evidence for the existence of migratory contingents within spawning populations. Our findings have significant implications for the management of the threatened Sacramento River population of green sturgeon, which migrates to inland waters outside of California where anthropogenic impacts, including fisheries bycatch and water pollution, may be a concern. Our results also illustrate the utility of acoustic tracking to elucidate the migratory behavior of animals that are otherwise difficult to observe.

Abstract Chinook salmon Oncorhynchus tshawytscha were introduced into the Lake Michigan basin from 1966 to 1968 with the transfer of fertilized eggs from the Green River Hatchery, Washington. In the more than three decades since this founding, Chinook salmon occur and are managed throughout the Great Lakes basin as a mixture of feral and supplemented populations. To evaluate the extent of genetic diversity since initial founding, we examined the pattern of variation at 18 allozyme loci among feral Chinook salmon populations in seven Michigan watersheds. We observed little divergence and low heterogeneity among the seven populations, which was consistent with the pattern expected in a single, randomly mating gene pool. We believe that the two major mechanisms contributing to the lack of among-population heterogeneity are the relatively recent founding from a single source and the routine homogenization from annual releases of hatchery-propagated, common-brood-source juveniles. We compared genetic diversity in the founded population with that of the source population to assess impacts from management activities or other events that might have caused genetic bottlenecks. Six rare alleles observed in the source stock were absent in our combined Michigan samples (N = 256), and frequencies for two of these alleles were significantly different (P ≤ 0.01) between the source and Michigan samples. Several other allele frequencies also differed significantly between the source and founded populations, providing evidence that one or more sources of genetic drift have affected allelic variation in the Michigan population. Although conservation of native genetic diversity is not a prevailing issue for Chinook salmon in Michigan waters, management approaches aimed at maintaining overall compositional and structural diversity and any recently evolved but undetected river-specific diversity should avoid further depletion of genetic variation in this important Great Lakes recreational resource.

Big data, such as vessel monitoring system (VMS) data, can provide valuable information on fishing behaviours. However, conventional methods of detecting behaviours in movement data are challenged when behaviours are briefer than signal resolution. We investigate options for improving detection accuracy for short-set fisheries using 581 648 position records from 181 vessels in the Gulf of Mexico bandit-reel fishery. We first investigate the effects of increasing VMS temporal resolution and find that detection accuracy improves with fishing-set duration. We then assess whether a feature engineering approach—in our case, changing the way pings are labelled when training a classifier—could improve detection accuracy. From a dataset of 12 184 observed sets, we find that the conventional point-labelling method results in only 49% of pings being correctly labelled as ‘fishing’, whereas a novel window-labelling method results in 88% of records being labelled as ‘fishing’. When the labelled data are used to train classifiers, point labelling attains true-positive/balanced-accuracy rates of only 37%/66%, whereas window labelling achieves 68%/83%. Finally, we map fishing distribution using the two methods, and show that point labelling underestimates the extent of fishing grounds by ∼33%, highlighting the benefits of window labelling in particular, and feature engineering approaches in general.

We examined the age structure of a population of adult red drum Sciaenops ocellatus in the eastern Gulf of Mexico to determine whether management-mediated changes in juvenile and subadult survival rates during the mid-1980s are now evident in the population's age structure. During 1996–1998, we sampled 908 adult red drum from seven different schools; six schools were sampled during September–October, and one was sampled during February. No significant difference was detected in year-class frequencies between schools. Red drum ranged in total length from 685 to 1,085 mm and in age from 3 to 29 years. Strong year-classes in 1986 and 1989 and weaker year-classes in 1987 and 1988 were observed in all samples. The increased abundance of adult red drum in observed age distributions correlated well with the abrupt decrease in juvenile red drum harvest in Florida that occurred during the mid- to late 1980s. Ever since the red drum harvest was reduced, the strong year-classes detected through age-0 sampling appear later in the adult population. The relative age structure of adult red drum in the eastern Gulf of Mexico can be a useful index of changes in adjacent inshore fishing pressure.

Bioenergetic approaches are increasingly used to understand how marine mammal populations could be affected by a changing and disturbed aquatic environment. There remain considerable gaps in our knowledge of marine mammal bioenergetics, which hinder the application of bioenergetic studies to inform policy decisions. We conducted a priority-setting exercise to identify high-priority unanswered questions in marine mammal bioenergetics, with an emphasis on questions relevant to conservation and management. Electronic communication and a virtual workshop were used to solicit and collate potential research questions from the marine mammal bioenergetic community. From a final list of 39 questions, 11 were identified as 'key' questions because they received votes from at least 50% of survey participants. Key questions included those related to energy intake (prey landscapes, exposure to human activities) and expenditure (field metabolic rate, exposure to human activities, lactation, time-activity budgets), energy allocation priorities, metrics of body condition and relationships with survival and reproductive success and extrapolation of data from one species to another. Existing tools to address key questions include labelled water, animal-borne sensors, mark-resight data from long-term research programs, environmental DNA and unmanned vehicles. Further validation of existing approaches and development of new methodologies are needed to comprehensively address some key questions, particularly for cetaceans. The identification of these key questions can provide a guiding framework to set research priorities, which ultimately may yield more accurate information to inform policies and better conserve marine mammal populations.

Abstract Environmental variability among freshwater habitats may influence migratory decisions in partially anadromous salmonids through (1) proximate effects on individual fish development and condition and (2) longer‐term genetic adaptations of populations to the various environments. However, the relative importance of the two factors has been difficult to sort out. We used the gonadosomatic index as an indicator of maturation—and therefore residency—in age‐1 and age‐2 parr collected from eight partially anadromous Oncorhynchus mykiss (Rainbow Trout/steelhead) populations occupying a diversity of freshwater habitats. Substantial environmental variability among the eight Hood Canal (Washington) streams had little effect on life history pathways in male and female offspring of anadromous females (hereafter, ANAD parr), with the exception of significantly higher maturation rates in male ANAD parr from one population (Little Quilcene River). Between 0% and 8% of the female ANAD parr had initiated maturation, whereas 33% (Duckabush River) or 53% (Hamma Hamma River) maturation was observed among the female offspring of resident females (hereafter, RES parr) in the two populations with substantial resident components. The results indicate strong maternal control over offspring life history pathways in systems where resident and anadromous forms are sympatric. The RES parr that were collected above and below barriers to anadromy showed similar likelihoods of maturation. The expression of residency and anadromy in Hood Canal populations appears to reflect genetic adaptations to the diverse freshwater habitats (including the effects of O. mykiss sequestered above anadromy barriers) and, to some degree, the phenotypically plastic responses of male parr to the environmental variability among streams.

The potential role of morbillivirus was evaluated in the deaths of >1100 bottlenose dolphins Tursiops truncatus and other small cetaceans that stranded from February 2010 through July 2014, during the northern Gulf of Mexico (GoM) unusual mortality event (UME). Morbillivirus analysis was carried out on 142 live or freshly dead cetaceans and results were combined with samples from 102 live, free-ranging bottlenose dolphins sampled during capture-release health assessments conducted from 2011 to 2014. Polymerase chain reaction (PCR) testing for morbillivirus showed that 9.9% (14/142) of the stranded cetaceans and 1% (1/83) of the free-ranging live dolphins were positive for dolphin morbilliviral (DMV) RNA. In contrast, previous DMV dolphin die-offs had DMV detectable by PCR in 61 to 97% of animals tested. Histologic findings consistent with morbillivirus infection, including lymphoid depletion, bronchointerstitial pneumonia, syncytial cell formation, or meningoencephalitis, were found in 6.6% (9/136) of the cetaceans that underwent histologic examinations. Serological analysis using a virus neutralization assay found that 29% (5/17) of live stranded and 23% (23/102) of live free-ranging bottlenose dolphins had titers of 64 or greater for cetacean morbillivirus, indicating prior but not necessarily recent exposure to morbillivirus. Current findings suggest that DMV infection, although present in the northern GoM, was sporadic and occurred at low levels and therefore was not the primary cause of the northern GoM UME. Confirmation of DMV infections and existing DMV titers demonstrate continued exposure to morbillivirus among northern GoM cetaceans since the first detection of this virus in the early 1990s.

By ending the “race to fish” catch share programs may be expected to lead to improved productivity at the fishery level by retiring redundant capital and by allowing fishing firms to become more technically efficient in their harvesting activities by, among other things, changing the composition of inputs and outputs. Yet, there have been relatively few empirical studies of productivity changes in catch share fisheries and no comprehensive treatment of a cross-section of programs using a common measure of productivity change. In this study estimates of multi-factor productivity change for 20 catch share fisheries in the U.S. using a Lowe index are provided. With few exceptions, productivity increased relative to baseline conditions during the first three years of catch share program implementation. For five of six of the most established catch share programs, these initial productivity gains have been maintained or have continued to improve.

There is broad interest in the development of efficient marine protected areas (MPAs) to reduce bycatch and end overfishing of speckled hind (Epinephelus drummondhayi) and warsaw grouper (Hyporthodus nigritus) in the Atlantic Ocean off the southeastern U.S. We assimilated decades of data from many fishery-dependent, fishery-independent, and anecdotal sources to describe the spatial distribution of these data limited stocks. A spatial classification model was developed to categorize depth-grids based on the distribution of speckled hind and warsaw grouper point observations and identified benthic habitats. Logistic regression analysis was used to develop a quantitative model to predict the spatial distribution of speckled hind and warsaw grouper as a function of depth, latitude, and habitat. Models, controlling for sampling gear effects, were selected based on AIC and 10-fold cross validation. The best-fitting model for warsaw grouper included latitude and depth to explain 10.8% of the variability in probability of detection, with a false prediction rate of 28-33%. The best-fitting model for speckled hind, per cross-validation, included latitude and depth to explain 36.8% of the variability in probability of detection, with a false prediction rate of 25-27%. The best-fitting speckled hind model, per AIC, also included habitat, but had false prediction rates up to 36%. Speckled hind and warsaw grouper habitats followed a shelf-edge hardbottom ridge from North Carolina to southeast Florida, with speckled hind more common to the north and warsaw grouper more common to the south. The proportion of habitat classifications and model-estimated stock contained within established and proposed MPAs was computed. Existing MPAs covered 10% of probable shelf-edge habitats for speckled hind and warsaw grouper, protecting 3-8% of speckled hind and 8% of warsaw grouper stocks. Proposed MPAs could add 24% more probable shelf-edge habitat, and protect an additional 14-29% of speckled hind and 20% of warsaw grouper stocks.

In 2018, the giant manta ray was listed as threatened under the U.S. Endangered Species Act. We integrated decades of sightings and survey effort data from multiple sources in a comprehensive species distribution modeling (SDM) framework to evaluate the distribution of giant manta rays off the eastern United States, including the Gulf of Mexico. Manta rays were most commonly detected at productive nearshore and shelf-edge upwelling zones at surface thermal frontal boundaries within a temperature range of approximately 20-30 °C. SDMs predicted highest nearshore occurrence off northeastern Florida during April, with the distribution extending northward along the shelf-edge as temperatures warm, leading to higher occurrences north of Cape Hatteras, North Carolina from June to October, and then south of Savannah, Georgia from November to March as temperatures cool. In the Gulf of Mexico, the highest nearshore occurrence was predicted around the Mississippi River delta from April to June and again from October to November. SDM predictions will allow resource managers to more effectively protect manta rays from fisheries bycatch, boat strikes, oil and gas activities, contaminants and pollutants, and other threats.

Abstract The Magnuson–Stevens Fishery Conservation and Management Reauthorization Act of 2006 required regional fishery management councils to implement annual catch limits (ACLs) for nearly all stocks under U.S. federal management. Since 2011, the number of stocks requiring ACLs (and monitoring) has increased nearly 10-fold, with strict accountability measures requiring either in-season quota closures or shortening of subsequent seasons to avoid ACL overages. Robust forecasts of landings can also provide a projected baseline for evaluation of proposed management alternatives. We compared generalized linear models (GLMs), generalized additive models (GAMs), and seasonal autoregressive integrated moving average (SARIMA) models in terms of fit, accuracy, and ability to forecast landings of four representative fish stocks that support recreational fisheries in the southeastern United States. All models were useful in developing reliable forecasts to inform management. The GAMs provided the best fit to the observed data; however, the modeling approaches of the SARIMA model and GLM provided the best forecasts for most scenarios. The SARIMA model and GLM also provided the best predictions of the seasonal trend in landings, a desirable feature for in-season quota monitoring. The SARIMA model was more sensitive and the GLM was less sensitive to recent trends, providing a useful “bookend” for forecasts. The time span of input data affected forecast accuracy from all model types considered. This study suggests multiple forecasting models should be investigated and performance metrics carefully selected and evaluated, as no single model is likely to perform best for all stocks of interest. Received December 18, 2014; accepted April 20, 2015

Understanding aspects of reproduction is important for studies of life history strategy and for resource management. The influences of nine factors (five intrinsic, four extrinsic) on the reproductive attributes egg diameter, egg dry weight, and clutch size (i.e., number of eggs in egg mass) of female stone crabs (genus Menippe (Say)) from Tampa Bay, FL, waters were investigated. Two intrinsic factors influenced reproductive attributes: carapace width was positively correlated with clutch size, and egg stage was positively related to egg size. Three intrinsic factors—genotype class, damaged or missing pleopods, and missing claws or legs—had no influence on any reproductive attribute. The four extrinsic factors each influenced at least two reproductive attributes. Egg diameter and weight were significantly larger and clutch size was significantly smaller (1) in females uninfested by Octolasmis mülleri; (2) during the early part of the spawning season, when water temperature was 27°C or less; and (3) during the first year of the 3-y study. In addition, egg diameter varied significantly among season/year combinations. In all cases, when egg diameter and weight decreased, clutch size increased; suggesting that, in female stone crabs, selection for filling the available abdominal space with eggs is strong. Large eggs are known to produce larvae of high fitness in crabs. Because the largest eggs are produced during the early part of the spawning season, females should be protected from harvest during that time. Shortening the harvest season in spring would eliminate those females from vulnerability to the fishery.

When oil spills occur in the marine environment, many species of wildlife in that ecosystem may be either directly or indirectly impacted. The impacts of spilled oil on birds are well known In comparison, marine mammals (and, in particular, cetaceans and sirenians) have only infrequently been documented