Environmental control of Northeast Atlantic mackerel (Scomber scombrus) recruitment in the southern Bay of Biscay: case study of failure in the year 2000

We investigate the effect of strong meteorological perturbations in early spring on the success of mackerel (Scomber scombrus) recruitment in the N/NW Iberian area (southern Bay of Biscay) for the period 1999–2008. In 2000, the year of the most pronounced recruitment failure on record, two consecutive multidisciplinary surveys sampled hydrographic conditions and mackerel eggs, larvae and post‐larvae over the main mackerel spawning grounds of the north and northwest coast of the Iberian Peninsula. Analysis of egg and larval abundance and birthdates based on the otoliths of mackerel juveniles caught between July and October 2000 showed that there were no survivors from the early spring spawns, indicating a massive loss of early spawning effort. Moreover, the abundance of 1‐year‐old mackerel estimated from an acoustic survey carried out in 2001 was the lowest observed within the 1999–2008 time series. This low or null survival from the early spawns in 2000 could be due to the meteorological and oceanographic conditions of that spring, in particular two storm events in April after a relatively calm March. The first storm event from the north caused strong local wind in the southern Bay of Biscay but a weak oceanographic response. The second storm event from the southwest was mainly felt west of Galicia and caused a notable increase in shelf currents and a shift of the hydrographical structure along the shelf. Detailed analysis of strong wind pulses in early spring within the historical recruitment record suggests that strong local turbulence generated by high wind speeds and advection of larvae caused by the enhancement of shelf currents can contribute to reduced recruitment. Our observations indicate that, in 2000, both mechanisms were present.     

The role of integrating agroforestry and vegetable planting in structuring communities of herbivorous insects and their natural enemies in the Neotropical region

The integration of agroforestry plots with ephemeral crops such as vegetables on the farm scale can probably serve as a refuge and source of beneficial insects. Therefore, agroforestry systems possibly represent an alternative that favors ecosystem services and help growers in the transition process from conventional to agro-ecological agriculture. This study aimed to understand the role of introducing agroforestry systems in structuring insect communities, with consequences for the abundance of herbivore and natural enemies, contributing to farm management and favoring biological control as an ecosystem service. Field surveys showed that agroforestry systems can harbor more species than horticultural crops, independent of the functional group. They also contain a greater diversity of herbivores and an even greater diversity profile of natural enemy communities. Agroforestry systems served as a source of natural enemies that can colonize horticultural crops when herbivores are present. As a consequence, natural enemies can establish a numerical response to herbivore abundance, but their communities are also affected by stochastic factors related to climatic conditions. Thus, agroforestry systems and agro-ecological practices might favor an agriculture based on the maintenance and conservation of ecosystem services.     

Groundwater Contamination by Landfill Leachates in a Karstic Aquifer

The contamination of a karstic aquifer by the leachate from the urban solid waste landfill of La Mina (Marbella, south of Spain) has been monitored. A characterization of the karstic media and the different storages of water in the carbonate rock have been deduced by the study of the hydrodynamic and hydrochemical variations in water points of the study network. The chemical compositions of four springs, three pumping wells and five piezometers in the surroundings of the landfill, yield two patterns of hydrochemical behaviour at the contaminated points: (1) the contamination at the piezometers, measured by the concentration of Cl^? and by electrical conductivity, increased over time, but was associated with the precipitation of calcite, evidenced by a reduction in the concentration of HCO₃ ^? and Ca²⁺; (2) at points near the landfill, contamination also increased, but the CO₂ from the landfill provoked an additional dissolution of carbonate minerals, a process reflected in the high concentrations of hydrogen carbonate, calcium and magnesium. The contaminated points were irregularly distributed, the most distant piezometer presenting the greatest impact, whereas no traces of contamination were detected at one piezometer close to the landfill. The irregular distribution of these processes is explained by the heterogeneity of the karstic media, with different types of storage (conduits, fractures/fissures and matrix) and a difference in density between the leachate and the groundwater.     

Postpartum toll-like receptors and β-defensin 5 mRNA levels in the endometrium of Holstein cows

Toll-like receptors (TLRs) and β-defensins are important components of the innate immune system. This study aimed to evaluate endometrial mRNA levels of TLRs (1/6, 2, 4, and 5) and β-defensin 5 in Holstein cows by quantitative real time RT-PCR. Uterine biopsies were performed from 6 to 12 h after parturition, and cows were divided into two groups: (i) cows with placental retention and clinical signs of uterine infection until 45 days postpartum (n=10) or (ii) cows with normal puerperium (n=10). All cows had detectable levels of TLRs and β-defensin 5 mRNAs, but these levels did not differ between groups (P>0.05). Levels of TLR4 mRNA had a positive and significant correlation with the time required for uterine involution in both groups.     

ULTRASONOGRAPHIC FINDINGS IN HORSES WITH FOOT PAIN BUT WITHOUT RADIOGRAPHICALLY DETECTABLE OSSEOUS ABNORMALITIES

Foot pain is an important cause of lameness in horses. When horses with foot pain have no detectable radiographic abnormalities, soft‐tissue assessment remains a diagnostic challenge without magnetic resonance (MR) imaging. Ultrasonography can provide an alternative to MR imaging when that modality is not available but the extent of changes that might be seen has not been characterized. We reviewed the ultrasonographic findings in 39 horses with lameness responding positively to anesthesia of the palmar digital nerves and without radiographically detectable osseous abnormalities. Thirty of the 39 horses had lesions affecting the deep digital flexor tendon (DDFT), 27 had abnormalities in the distal interphalangeal joint of which six had a visible abnormality in the collateral ligament. Ultrasonographic abnormalities were seen in the podotrochlear bursa in 22 horses and in the ligaments of the navicular bone in two horses. Abnormalities of the navicular bone flexor surface were detected in eight horses. In three of the 39 horses, only the DDFT was affected. The other 36 horses had ultrasonographic abnormalities in more than one anatomical structure. Based on our results, ultrasonographic examination provides useful diagnostic information in horses without radiographic changes.     

USE OF TRANSSPLENIC INJECTION OF AGITATED SALINE AND HEPARINIZED BLOOD FOR THE ULTRASONOGRAPHIC DIAGNOSIS OF MACROSCOPIC PORTOSYSTEMIC SHUNTS IN DOGS

We describe the use of ultrasonography‐guided percutaneous splenic injection of agitated saline and heparinized blood for the diagnosis of portosystemic shunts (PSS) in 34 dogs. Agitated saline mixed with 1 ml of heparinized autologous blood was injected into the spleen of 34 sedated dogs under sonographic guidance. The transducer was then sequentially repositioned to visualize the portal vein, the caudal vena cava, and the right atrium through different acoustic windows. It was possible to differentiate between intrahepatic and extrahepatic shunts depending on the entry point of the microbubbles into the caudal vena cava. Portoazygos shunts and portocaval shunts could be differentiated based on the presence of microbubbles in the caudal vena cava and/or the right atrium. In one dog, collateral circulation due to portal hypertension was identified. In dogs with a single extrahepatic shunt, the microbubbles helped identify the shunting vessel. The technique was also used postoperatively to assess the efficacy of shunt closure. All abnormal vessels were confirmed by exploratory laparotomy or with ultrasonographic identification of the shunting vessel. Ultrasound‐guided transsplenic injection of agitated saline with heparinized blood should be considered as a valuable technique for the diagnosis of PSS; it is easy to perform, safe, and the results are easily reproducible.     

Effect of intraruminally administered, selenium soluble-glass boluses on selenium status in cows and their calves

Intraruminal selenium soluble-glass boluses were administered by balling gun to 65 of 125 crossbred beef cows (Shorthorn X Charolais) during the last trimester of pregnancy. Elevated (P less than .01) whole blood glutathione peroxidase (GSH-Px) concentrations were observed monthly for the next 10 mo following initiation of treatment, reaching the maximum magnitude (263 vs 41) at the fourth month. Monthly milk samples showed elevated selenium concentrations (P less than .01, April through August; P less than .05 through September). Intraruminal, selenium soluble-glass bolus administration to gestating cows was highly effective in raising the selenium status of their progeny. Although the control calves were in low-selenium status, no acute cases of nutritional muscular dystrophy were observed during this experiment.     

Hypomagnesaemia in beef cows wintered in Ontario.

A field experiment was undertaken in northern Ontario in order to assess the magnesium status of beef cattle raised in the area. Magnesium status was assessed using several criteria including blood and urine magnesium levels, and bone biopsy samples. Eighteen groups each containing four pregnant Shorthorn beef cows were used. Each of the following three mineral feeds were offered to six groups throughout the experiment: a mineral feed without magnesium, a mineral feed containing 8% magnesium in the form of magnesium oxide and the third containing sequestered magnesium with a magnesium level of about a tenth of that in the mineral feed containing magnesium oxide. During the winter, when the cows were housed indoors, they were fed grass silage. Six groups, two of each mineral feed, remained indoors throughout the summer. The other 12 groups were turned out to pasture on May 25 and continued receiving the appropriate mineral feed. There were no differences in serum magnesium owing to magnesium-supplementation treatments observed at any time during any experiment. Serum magnesium levels fell drastically in all groups before the cows were released to pasture, implying that the hypomagnesaemic condition was attributable to the stress of yarding. The rate of recovery from hypomagnesaemia was slower in the cows released to pasture than in those kept indoors. Urine samples from cows returned to the pasture were indicative of low magnesium status. At the end of the experiment, the magnesium levels in the bones of the housed animals were higher than for those on pasture. In spite of severe cases of hypomagnesaemia, no clinical signs of this metabolic condition were observed.     

The performance of three ordination methods applied to demersal fish data sets: stability and interpretability

Abstract The performance of robust principal component analysis (RPCA), detrended correspondence analysis (DCA) and non‐metric multidimensional scaling (NMDS) with two demersal fish data sets were assessed in terms of their stability to bootstrap‐generated sample variation and the method’s ability to reflect a well‐known depth gradient. Stability was assessed for both species and site orderings and configurations, using scaled rank variance (SRV) and Spearman (ρ) and Procrustes correlations (t₀). The NMDS site and species orderings showed the highest stability. DCA performed best in terms of site ordination stability, but NMDS performed best in terms of species ordination stability. In terms of matching the expected ecological variation, NMDS was the most sensitive method for the wider‐depth gradient data and DCA was the most sensitive for the narrower‐depth gradient data. According to the sensitivity and informative power criteria associated with the stability assessment, t₀ was the best methodological approach for site ordinations, and SRV for species ordinations.     

Multispecies fisheries management and conservation: tactical applications using models of intermediate complexity

Stakeholders increasingly expect ecosystem assessments as part of advice on fisheries management. Quantitative models to support fisheries decision‐making may be either strategic (‘big picture’, direction‐setting and contextual) or tactical (focused on management actions on short timescales), with some strategic models informing the development of tactical models. We describe and review ‘Models of Intermediate Complexity for Ecosystem assessments’ (MICE) that have a tactical focus, including use as ecosystem assessment tools. MICE are context‐ and question‐driven and limit complexity by restricting the focus to those components of the ecosystem needed to address the main effects of the management question under consideration. Stakeholder participation and dialogue is an integral part of this process. MICE estimate parameters through fitting to data, use statistical diagnostic tools to evaluate model performance and account for a broad range of uncertainties. These models therefore address many of the impediments to greater use of ecosystem models in strategic and particularly tactical decision‐making for marine resource management and conservation. MICE are capable of producing outputs that could be used for tactical decision‐making, but our summary of existing models suggests this has not occurred in any meaningful way to date. We use a model of the pelagic ecosystem in the Coral Sea and a linked catchment and ocean model of the Gulf of Carpentaria, Australia, to illustrate how MICE can be constructed. We summarize the major advantages of the approach, indicate opportunities for the development of further applications and identify the major challenges to broad adoption of the approach.