Efficiency of working dogs undergoing a new Human Familiarization and Training Program

The study of human-dog interaction has increased over the past several years. It has been demonstrated that dogs can use a number of human social cues to successfully accomplish a task, and that they do so better than apes. Many authors agree that these abilities are a result of 10,000 years of domestication by humans. Domestication may have genetically predisposed dogs to accurately recognize human communication signals. However, only a few authors have studied the performance of working dogs, implying recognition of human communication signals. Haverbeke et al. (2008) found that military working dogs do not always perform as they are expected to. To investigate this finding, we studied the performance of obedience and protection work exercises between 2 groups of dog-handler teams: a control group (CG), trained using the current training method used by the Belgian Defense, and an experimental group (EG) that underwent a new human familiarization and training program. During obedience and protection work exercises, EG teams obtained better results than CG teams and EG dogs exhibited a higher body posture than CG dogs. The results suggest that even if dogs are genetically predisposed toward the recognition of human communication signals, this aptitude alone does not explain the dogs' performance and their interactions with humans in this study. Regular training combined with positive dog-handler interaction is also required to increase the dog-handler (DH) team's performances.     

Influence of high temperature on cadmium-induced skeletal deformities in juvenile mosquitofish (<Emphasis Type="Italic">Gambusia affinis</Emphasis>)

The aim of this study was to assess the effect of high temperature on cadmium (Cd)-induced skeletal deformities in juvenile Mosquitofish, Gambusia affinis. For this purpose, 188 juveniles (1 day old) were equally divided into the control group, which was maintained in Cd-free water at 24°C, and three treated groups exposed either to Cd (0.4 mg/l as Cd Cl₂) at 24°C, to high temperature (32°C), or to Cd at 32°C for 30 days. The results showed that Cd exposure at 24°C significantly increased the Cd accumulation (P < 0.0001) in the whole tissues of juveniles as well as the incidence of skeletal deformities (P < 0.01) compared with control animals. Exposure to high temperature also led to a significant increase in the incidence of skeletal deformities (P < 0.01) with respect to the control group. Interestingly, our results showed that the combined exposure to Cd and high temperature led to a more significant increase in Cd accumulation and in the frequency of spinal deformities than exposure to Cd or high temperature alone. These results confirm that temperature increases Cd toxicity and needs to be taken into account for the accurate prediction and assessment of Cd-induced spinal deformities in fish.     

Effect of type of bait on pelagic longline fishery–loggerhead turtle interactions in the Gulf of Gabes (Tunisia)

• 1. Sea turtles may migrate vast distances from their feeding areas to home rookeries where they nest. During these migrations sea turtles are subject to many threats, among which are interactions with pelagic longlines.
• 2. This gear is used frequently in the summer period in the Gulf of Gabes targeting mainly the sandbar shark (Carcharhinus plumbeus). Hooks are baited with mackerel (Scomber scombrus) or pieces of stingray (Dasyatis pastinaca).
• 3. Twenty‐one fishing trips (48 sets with a total of 35 950 hooks deployed) were conducted using onboard observers in the south of the Gulf of Gabes during the months of July, August and September in 2007 and 2008. Stingray and mackerel bait were used in 19 and 29 sets, respectively.
• 4. In total, 29 loggerhead sea turtles (Caretta caretta) were captured; the majority of them were juvenile and active. Turtles were caught at a statistically greater frequency on sets with hooks baited with mackerel than on sets with hooks baited with pieces of stingray.
• 5. The type of bait also affected the catch of the target species by increasing the efficiency when pieces of stingrays were used.
• 6. These results encourage further research into new baits to mitigate turtle catch by longline fisheries without affecting the catch of target species. Copyright © 2010 John Wiley & Sons, Ltd.

     

Compositional quality of virgin olive oils from cultivars introduced in Tunisian arid zones in comparison to Chemlali cultivars

This work is an evaluation of the quality of three introduced European olive cultivars Arbequina, Coratina, and Koroneiki grown under a biological agricultural system in the arid zone of Sfax in Tunisia compared to Chemlali cultivars. Various olive parameters were analyzed, such as ripening index, pulp/stone (P/S) ratio and oil content. We have considered the regulated physicochemical analytical parameters, fatty acids and minor compounds for olive oil. The most of the quality indices and fatty acid composition showed significant variations among olive cultivars. The Koroneiki, Coratina and Chemlali Zarzis cultivars had highest values of oleic acid (62.7%) (76.8%, 75.8% and 73.9%, respectively), Arbequina, had lowest value of oleic acid and similar to Chemlali Sfax. Coratina was noteworthy for its higher content of phenolic compounds (287.8 mg kg⁻¹), oil content (42.4%) and P/S ratio (4.7%). Although their low phenol contents, autochthonous cultivars presented high contents of α-tocopherol (577.8 and 434.6 mg kg⁻¹ for Chemlali Boughrara and Chemlali Zarzis, respectively) except for Chemlali Sfax. In conclusion, European cultivars seem to have adapted to the area studied according to their oil biochemical composition while the increase observed in their α-tocopherol levels. The cultivar Arbequina showed a similar composition of Chemlali Sfax.