Molecular evidence for cosmopolitan distribution of platyhelminth parasites of tunas (Thunnus spp.)

Global distribution of platyhelminth parasites and their host specificities are not well known. Our hypothesis was that platyhelminth parasites of large pelagic fishes are common around the world. We analysed molecular variation in three different taxa of platyhelminth parasites infecting four species of tunas: yellowfin tuna (Thunnus albacares, Scombridae) from Western Australia, southern bluefin tuna (Thunnus maccoyii, Scombridae) from South Australia, Pacific bluefin tuna (Thunnus orientalis, Scombridae) from Pacific Mexico and northern bluefin tuna (T. thynnus, Scombridae) from two localities in the Mediterranean (Spain and Croatia). Comparisons of ITS2 and partial 28S rDNA demonstrated two congeneric species of blood flukes (Digenea: Sanguinicolidae) from multiple hosts and localities: Cardicola forsteri from southern bluefin and northern bluefin tunas, and Cardicola sp. from Pacific bluefin and northern bluefin tunas; and a gill fluke, Hexostoma thynni (Polyopisthocotylea: Hexostomatidae), from yellowfin, southern bluefin and northern bluefin tunas. Partial 28S rDNA indicates that a second type of fluke on the gills, Capsala sp. (Monopisthocotylea: Capsalidae), occurs on both southern bluefin and Pacific bluefin tunas. This appears to be the first report of conspecific platyhelminth parasites of teleosts with a wide‐ranging geographical distribution that has been confirmed through molecular approaches. Given the brevity of the free‐living larval stage of both taxa of flukes on the gills (H. thynni and Capsala sp.), we conclude that the only feasible hypothesis for the cosmopolitan distribution of these flatworms is migrations of host tunas. Host migration also seems likely to be responsible for the widespread occurrence of the two species of blood flukes (Cardicola spp.), although it is also possible that these were translocated recently by the spread of infected intermediate hosts.     

Laparoscopic esophagopexy,fundopexy, and hiatal herniorrhaphy for refractory regurgitation in a racing Alaskan husky sled dog

A 2-year-old intact female Alaskan husky sled dog was presented with a history of chronic exercise-induced regurgitation refractory to medical management. Previous diagnostics were unremarkable except for an endoscopic examination and histopathologic evaluation of the upper gastrointestinal tract that revealed the presence of Helicobacter spp. and mild non-specific inflammation of the proximal duodenum. A laparoscopic hiatal herniorrhaphy, esophagopexy, fundopexy, and ovariectomy were performed without complications in anesthesia or surgery and clinical improvement was observed with continued follow-up for 8 months after surgery.Key clinical message:Surgical treatment for hiatal hernia may be considered in racing Alaskan sled dogs with regurgitation refractory to gastric protectant therapy.     

The quality of service provided by the irrigation department to the users associations, Tunuyan System, Mendoza, Argentina

The quality of service provided by the provincial Irrigation Department (DGI) to the Water Users Associations (UA), and subsequently by the UA's to the related water users, is based on the provincial water law. The intended volume of water being delivered per considered period further depends on the water availability and on the (crop irrigation) water requirements. The Service Level (SL) compares the intended water supply with the water supply that would be required to supply the entire irrigable area with sufficient water. As soon as the intended water delivery pattern is set, the measured actual delivery can be assessed against the intention. Several performance indicators are used in this context. Based on the assessment of the Water Delivery Performance Ratio and the Overall Consumed Ratio recommendations are made on changes which can be made to improve water use and reduce problems of waterlogging.     

Correction to: Individual based modelling of fish migration in a 2-D river system: model description and case study

Landscape Ecology - In the original publication of the article, the third author name has been misspelt. The correct name is given in this Correction. The original version of this article was revised.     

Environmental heterogeneity and biotic interactions as potential drivers of spatial patterning of shorebird nests

Context

Species distributions are driven by a wide variety of abiotic and biotic factors, including nest placement for breeding individuals. As such, the spatial distribution of nests within a landscape can reflect environmental heterogeneity, habitat preferences, or even interactions with predators and other species.

Objectives

We determined the extent to which environmental heterogeneity and predation risk accounted for the observed spatial distribution of nests.

Methods

We assessed the spatial distribution of 112 nests of a migratory shorebird, the Hudsonian Godwit (Limosa haemastica), at Beluga River, Alaska, from 2009 to 2012, and explicitly tested for the relative influence of habitat characteristics and predation risk on nest locations. We also evaluated the effect of nest location, distance to conspecific nests, and proximity to roads on nest fate using 64 nests that were monitored through completion.

Results

Hudsonian Godwit nests were clustered across the landscape despite a lack of significant spatial autocorrelation (i.e., patchiness) in vegetation characteristics at either the micro- or landscape scale. Nest fate also was not predicted by either the distance to the nearest conspecific neighbor or proximity to roads. Thus, neither habitat characteristics nor predation risk explained the clustering of godwit nests.

Conclusions

These results suggest that godwits may select nest locations based more on social cues than underlying heterogeneity in vegetation or predation risk. As such, intra- and inter-specific interactions should be considered when developing management plans for species of conservation concern.

     

A Syndrome Resembling Idiopathic Noncirrhotic Portal Hypertension in 4 Young Doberman Pinschers

We describe 4 young male Doberman Pinschers (3 littermates and 1 unrelated dog) with a syndrome resembling idiopathic or noncirrhotic portal hypertension of humans. Each dog was evaluated for a hepatopathy resulting in portal hypertension, development of portosystemic collateral vessels, and hepatic encephalopathy. These dogs differ from previous reports of young dogs with hepatic insufficiency associated with portal hypertension and acquired portal systemic shunting by their lack of intrahepatic arteriovenous fistulae, portal vein atresia, or intrahepatic fibrosis. Clinicopathologic features included erythrocyte microcytosis, normal to mildly increased liver enzyme activities, increased concentrations of serum bile acids, reduced plasma indocyanine green clearance, and normal total bilirubin concentration. Abdominal ultrasonography disclosed a small liver and portosystemic collateral vessels. Radiographic imaging studies confirmed hepatofugal portal circulation and discounted hepatic arteriovenous fistulae. Histopathologic features in liver tissue from each dog were similar and consistent in all sections examined. Common findings included increased cross-sectional views of hepatic arterioles; hepatic lobular atrophy; scanty increase in connective tissue around some large portal triads; and absence of inflammation, disturbed lobular architecture, bile duct proliferation, or intrahepatic cholestasis.     

The effects of azadirachtin and nucleopolyhedrovirus on midgut enzymatic profile of Spodoptera litura Fab. (Lepidoptera: Noctuidae)

The effects of azadirachtin (AZA) and nucleopolyhedrovirus (NPV) on midgut enzyme activity in Spodoptera litura Fabricius (Lepidoptera: Noctuidae) (Tobacco cutworm) were evaluated. Gut enzyme activities were decreased by AZA and NPV individually and in combination. When S. litura larvae were fed a diet of castor leaves treated with AZA and NPV in bioassays, gut enzyme—acid phosphatases, alkaline phosphatases, adenosine triphosphatases, and lactate dehydrogenase—activities were decreased. There were statistically significant differences (P ? 0.05) in enzyme activities between combined and individual treatment. A synergistic effect of botanical insecticides and virus was found when combined in low doses. These effects are most pronounced in early instars. Maximum weight loss (59-72%) occurred, when AZA and NPV were combined.     

Pattern in escalations in insurgent and terrorist activity

In military planning, it is important to be able to estimate not only the number of fatalities but how often attacks that result in fatalities will take place. We uncovered a simple dynamical pattern that may be used to estimate the escalation rate and timing of fatal attacks. The time difference between fatal attacks by insurgent groups within individual provinces in both Afghanistan and Iraq, and by terrorist groups operating worldwide, gives a potent indicator of the later pace of lethal activity.     

Water use and carbon exchange of red oak- and eastern hemlock-dominated forests in the northeastern USA: implications for ecosystem-level effects of hemlock woolly adelgid

Water use and carbon exchange of a red oak-dominated (Quercus rubra L.) forest and an eastern hemlock-dominated (Tsuga canadensis L.) forest, each located within the Harvard Forest in north-central Massachusetts, were measured for 2 years by the eddy flux method. Water use by the red oak forest reached 4 mm day(-1), compared to a maximum of 2 mm day(-1) by the eastern hemlock forest. Maximal carbon (C) uptake rate was also higher in the red oak forest than in the eastern hemlock forest (about 25 versus 15 micromol m(-2) s(-1)). Sap flux measurements indicated that transpiration of red oak, and also of black birch (Betula lenta L.), which frequently replaces eastern hemlock killed by hemlock woolly adelgid (Adelges tsugae Annand.), were almost twice that of eastern hemlock. Despite the difference between species in maximum summertime C assimilation rate, annual C storage of the eastern hemlock forest almost equaled that of the red oak forest because of net C uptake by eastern hemlock during unusually warm fall and spring weather, and a near-zero C balance during the winter. Thus, the effect on C storage of replacing eastern hemlock forest with a forest dominated by deciduous species is unclear. Carbon storage by eastern hemlock forests during fall, winter and spring is likely to increase in the event of climate warming, although this may be offset by C loss during hotter summers. Our results indicate that, although forest water use will decrease immediately following eastern hemlock mortality due to the hemlock woolly adelgid, the replacement of eastern hemlock by deciduous species such as red oak will likely increase summertime water use over current rates in areas where hemlock is a major forest species.     

Bottlenose dolphins (Tursiops truncatus) in the north-western Adriatic Sea: Spatial distribution and effects of trawling

1. Many species and populations of odontocetes have modified their behaviour to take advantage of feeding opportunities provided by fishing activities, with depredation of fishing gear being the most common type of adaptation.
2. The northern Adriatic Sea has been identified as an important marine mammal area because of a regular occurrence of common bottlenose dolphins. Boat surveys were conducted within a 3,000 km² sector of the Adriatic Sea off the coast of Veneto, Italy, between April and October 2018–2019. Based on 76 days at sea, 10,711 km of navigation, and 81 h 26 min of dolphin tracking, this study contributes novel quantitative information on dolphin spatial distribution, and on their occurrence in the wake of beam trawlers, otter trawlers, and midwater pair trawlers.
3. A combined generalized additive model and generalized estimation equation framework indicated that trawling—along with other physiographic, biological and anthropogenic variables—influenced dolphin distribution. In days of trawling, the chance of encountering dolphins increased by ~4.5 times (95% confidence interval 1.8–11.0) near active beam trawlers, by ~16.0 times (7.1–36.0) near otter trawlers, and by ~28.9 times (12.0–69.6) near midwater pair trawlers.
4. Spatial modelling was used to create maps of predicted distribution, suggesting differences in habitat use between trawling and no-trawling days. Spatial modelling for all days identified a dolphin distribution hotspot of 832 km², situated off the Po river delta.
5. Evidence contributed by this study can be used to inform management action within one of the world's areas most heavily impacted by fishing and other human encroachment. Such management action would help enforce the European Union's Habitats Directive and Marine Strategy Framework Directive, while also informing EU's Maritime Spatial Planning.