The effects of ecolabels on environmentally- and health-friendly cars : an online survey and two experimental studies

Purpose: Given the increasing importance of political decision-making to reduce emission targets, the main purpose of the current paper is to identify and test the considerations that would nudge consumers towards an environmentally and health-friendly motor vehicle. Methods: An online survey was conducted to assess public responses and the role of public authorities to a voluntary emission standard for passenger cars. In addition, two online experiments were conducted to test incentives in the design of ecolabels (e.g. price, safety, performance) for optimization. A random sample of 6400 individuals was drawn from eight countries: Germany, Ireland, Italy, the Netherlands, Spain, UK, Czech Republic and Lithuania. An online survey was conducted among 3200 respondents, 400 in each of the 8 countries, and 2 online experiments with 3200 subjects, 400 in each of the 8 countries, allowing for 200 respondents for each experiment in each country. Results and discussion: The survey shows that Europeans are aware of the health and environmental impact of cars. The findings also confirm the gap between self-reported attitudes/intentions and actual behaviours. In influencing car purchase decisions, health and environmental concerns are less important than other attributes such as price, safety and performance. The experiments show that all these attributes have a significant effect on consumers\u2019 choices. However, message content was found to have the strongest effect. Respondents are more likely to choose European Union Low Emitting carS (EULES)-friendly cars when the label shows information on lower costs or lower taxes and less likely to be influenced by health-related benefits, convenient parking or access fees. Finally, combinations of one message with other elements\u2014EULES logo, CO2 logo or both\u2014within the same label have a small but positive effect on respondents\u2019 choices. Conclusions: The findings of this study assist governmental decision-making processes by identifying those issues that have the greatest impact on consumers\u2019 car purchasing decisions. Furthermore, the results will help to guide environmentally conscious customers towards the purchase of vehicles with clean emission profiles

Can product information steer towards sustainable and healthy food choices? A pilot study in an online supermarket:A pilot study in an online supermarket

Sustainable dietary choices have become increasingly important because of the current environmental threats the world is facing. Nonetheless, consumers find it difficult to assess a product’s sustainability and therefore make better choices. This pilot study tested whether explanatory product information about sustainability increased sustainable purchases in an online supermarket and whether additional health information increased message effectiveness. Perceived consumer effectiveness (i.e., the perception of the degree to which individual actions can contribute to environmental problems) and green skepticism were hypothesized to mediate the effect of message type, and environmental attitudes were included as the moderator. An experiment using a one-factor design was conducted among 101 participants who were assigned to one of three experimental conditions: sustainability claim only, explanatory sustainability claim, and explanatory sustainability and health claim. Analyses showed that an explanatory sustainability claim (regardless of whether this claim was accompanied by a health claim) led to fewer sustainable purchases through perceived consumer effectiveness but only for those with low environmental attitudes. No effects were found for the addition of a health claim. The results from this pilot provide insight for future studies that aim to examine how online supermarkets should communicate to increase sustainable purchases

Experimental evidence on measures to protect consumers of online gambling services

Online gambling has grown rapidly in recent decades due to increased accessibility and availability. This article reports the results of a behavioral experiment conducted in a laboratory (N=522) and an online experiment administered in seven European countries (N=5997). The experiments examined the effectiveness of a range of mainstream and also innovative protective interventions for online gambling. The rationale of the interventions was to disrupt both individuals\u2019 mental processes and the affordances embedded in the human-machine system designed to maximize the time spent gambling and industry profits. Behavioral measures including stake size, speed of play and decision to stop playing or make further gambles were recorded. The results show that interventions addressing both individuals\u2019 mental processes and the human-machine interaction are effective in reducing the stake size and in slowing down the pace of gambling. All other interventions directed at the level of the individual have no effect on behavior. The results show that traditional \u2018nudges\u2019 are not sufficient and structural features such as the affordances embedded by design into the online gambling machines must be addressed in order to effectively protect consumers of online gambling

Size-selective mortality of laboratory-reared Atlantic bluefin tuna larvae: evidence from microstructure analysis of otoliths during the piscivorous phase

Atlantic bluefin tuna (Thunnus thynnus) larvae show strong piscivorous feeding behavior at the very early larval stage and this enables them to grow at high rates. We conducted a laboratory experiment in which Atlantic bluefin tuna larvae were offered larval prey for the first time at different ages to simulate the early onset of piscivory at three treatments: yolk-sac larvae (YSL), delayed onset of piscivory (DYSL) and a solely planktivorous diet (Rotifers). The otolith microstructure was then used to compare the larval size distribution at the onset of the experiment with the estimated previous size-at-age of the survivors at the end of the experiment by back- calculation. Within a cohort, our results show size-selective mortality of the largest larvae independent of the differences in the timing of onset of piscivory and differences in growth patterns. The results also corroborate the rapid response of Atlantic bluefin tuna to piscivory in terms of growth reflected in the otolith increment widths. Being bigger did not infer a survival advantage and mortality rates did not decline with increasing larval size. Smaller size at a given age could under certain conditions and stages of development confer a survival advantage of individual members of a larval cohort when suitable small-sized prey is available.Versión del editor2,26

Otolith microstructure analyses in cultured Atlantic bluefin tuna larvae as a tool to provide accurate estimates of size selective growth and mortality

Being bigger is not always the best option to survive and mortality rates do not always decline with increasing larval size. Smaller size at a given age could under certain condition and at certain stages of development confer a survival advantage on individual members of a larval cohort. Reference

The effect of nutritional condition on the growth to post-flexion of bluefin tuna larvae under cultured condition

These findings indicate that protein synthesis increase in proportion to the flexion stage which is strongly associated with the development of the digestive system and therefore the increase in the nutritional condition. Ontogenetic differences in the RNA and DNA content will be discussed in more detail. Also, the pattern obtained for Atlantic bluefin tuna larva will be compared with those of other species

The effect of different short pulse feeding regimes on growth and survival of Atlantic bonito larvae Sarda sarda

One of the most easily manipulated variables in fish larval culture is the photoperiod. Long light photoperiod regimes are commonly used to enhance growth in commercial species. However, for species with a piscivorous larval period, as the Atlantic bonito (Sarda sarda), long time exposure to light could lead to a lower survival through aggressive behavior and cannibalism. One alternative could be modifications of the light and dark cycles during the photophase. These modifications can result in short pulse feeding regimes since bonito larvae fill up their stomach completely during light hours but do not feed in darkness. Little is known about how such intermittent feeding regimes affect growth and survival in fish. In this study, we tried different alternating and continuous light regimes during the culture of bonito larvae to identify the best regime that maximizes growth and survival.Fertilized eggs of Atlantic bonito were obtained from different spontaneous spawning events by a captive broodstock at the Spanish Institute of Oceanography (IEO) in Mazarrón. Bonito larvae 8 days post hatch (dph) were reared in 150 l tanks equipped with a lid that was used to cover and uncover the tanks to manipulate the hours of light and therefore pulse feeding regimes. Bonito larvae were always fed with yolk sac seabream larvae ad libitum. A total of three experiments were conducted. In all, a continuous dark period of 7.5hours was maintained from 24:00 to 7:30. All light regimes had a total of 9 light hours except for one that had 15hours of light (15L:9D). In the first experiment, light regimes provided alternating light and dark conditions of either 1.5, 3 or 4.5hours from 7:30 to 24:00). In the second experiment, the 3hours alternating light regime was compared to two continuous regimes of 15hours of light (15L:9D) and 9hours of light (9L:15D). These two experiments were conducted at the same temperature, 24.7±0.4°C. The third experiment was identical to the second experiment but at colder temperatures, 21.4±0.45°C. All regimes had 3 replicates. 10 larvae were sub-sampled 3 days after the experiments began and were ended after 6 days when all larvae were sampled. Due to slower growth, the third experiment ended after 9 days. The larvae were measured in standard length and individual dry weights were calculated. Larvae were counted in the tanks every 3 days to estimate survivorship. Final larval sizes in the alternating light regimes were larger in the 3hours than those obtained in the 1.5 and 4.5hours (first experiment, Fig. 1a, Tukey test p0.01). The 3hours alternating light regime yielded the largest larval sizes at the end of the experiment compared to the other alternating regimes. Final sizes at the 3hours regime were larger than those obtained under the 9L:15D continuous light regime at both temperatures. The time to satiation and the elapsed time to evacuate food totally from the gut in a similar species is about 3-4hours (Young and Davis, 1990). Our results suggest that a better strategy for bonito larvae growth is to fill their stomach more than once per day followed by a resting period when food is being digested. However, no effect was observed in terms of survival, possibly due to high abundance of larval prey. Changes in the light regime that result in pulse feeding can be a good strategy to increase growth in larval cultures when fitting well the evacuation and satiation rates

Metabolic rates in Atlantic bluefin tuna larvae: first data and methodological challenges

Atlantic bluefin tuna is an emblematic scombrid species, but many physiological aspects during the larval stages are still unknown. The mechanisms of how fish larvae balance growth and activity are of great interest since metabolic costs are very high compared to juveniles and adults. However, there is a lack of information about metabolic costs in scombrid larvae. This lack of data is probably related to the challenges associated to larval handling before and during respirometry trials. In this study for the first time, we: i) estimate the relationship between routine metabolic rate and the larval dry weight (mass scaling exponent) at 26°C, ii) measure metabolism under light and darkness and iii) explore the influence of nutritional status (RNA:DNA ratio) on the inter-individual variability in metabolic rates. The relationship between metabolism and size (ranging from 0.6 to 23 mg) was near isometric (slope, b=0.99), in contrast to the allometric relationship observed in most species (b=0.87). Our results show no significant differences in oxygen consumption under light and darkness. A possible regulation (decrease) of their swimming activity with the consequent decrease in the oxygen consumption in light situations is discussed. Nutritional condition did not explain the inter-individual differences in oxygen consumption. This study first reports metabolic rates of Atlantic bluefin tuna larvae and discusses the challenges of performing bioenergetics studies with early life stages of Scombrids

Vertical distribution of Atlantic bluefin tuna Thunnus thynnus and bonito Sarda sarda larvae is related to temperature preference

As part of the endeavor aiming at the domestication of Atlantic bluefin tuna (BFT; Thunnus thynnus), first sexual maturity in captivity was studied by documenting its occurrence and by characterizing the key hormones of the reproductive axis: follicle stimulating hormone (FSH) and luteinizing hormone (LH). The full length sequence encoding for the related hormone b-subunits, bftFSHb and bftLHb, were determined, revealing two bftFSHb mRNA variants, differing in their 50 untranslated region. A quantitative immuno-dot-blot assay to measure pituitary FSH content in BFT was developed and validated enabling, for the first time in this species, data sets for both LH and FSH to be compared. The expression and accumulation patterns of LH in the pituitary showed a steady increase of this hormone, concomitant with fish age, reaching higher levels in adult females compared to males of the same age class. Conversely, the pituitary FSH levels were elevated only in 2Y and adult fish. The pituitary FSH to LH ratio was consistently higher (>1) in immature than in maturing or pubertal fish, resembling the situation in mammals. Nevertheless, the results suggest that a rise in the LH storage level above a minimum threshold may be an indicator of the onset of puberty in BFT females. The higher pituitary LH levels in adult females over males may further support this notion. In contrast three year-old (3Y) males were pubertal while cognate females were still immature. However, it is not yet clear whether the advanced puberty in the 3Y males was a general feature typifying wild BFT populations or was induced by the culture conditions. Future studies testing the effects of captivity and hormonal treatments on precocious maturity may allow for improved handling of this species in a controlled environment which would lead to more cost-efficient farmingVersión del edito