Zoekresultaten

The effect of artificial reef design on the attraction of herbivorous fish and on coral recruitment, survival and growth

Fish assemblages of different types of artificial reefs can differ greatly in abundance, biomass and composition, with some reef types harboring over five times more herbivores than others. It is assumed that higher herbivorous fish abundance results in a higher grazing intensity, affecting the benthic community by means of enhanced coral recruitment, survival and growth. Territorial fish species might affect this process by chasing away other fish, especially herbivores. In this study we compared the fish assemblage, territorial behavior and grazing intensity by fish on two artificial reef types: reef balls and layered cakes, differing greatly in their fish assemblage during early colonization. In addition, the effect of artificial reef type on benthic development and coral recruitment, survival and growth, was investigated. Although layered cakes initially harbored higher herbivorous fish biomass, this effect was lost during consecutive monitoring events. This seems to be the result of the higher territorial fish abundance around the layered cakes where almost four times more chasing behavior was recorded compared to the reef balls. This resulted in a more than five times lower fish grazing intensity compared to the reef-ball plots. Although macroalgae were effectively controlled at both reefs, the grazing intensity did not differ enough to cause large enough structural changes in benthic cover for higher coral recruitment, survival or growth. The high turf algae cover, combined with increasing crustose coralline algae and sponge cover likely explained reduced coral development. We recommend further research on how to achieve higher grazing rates for improved coral development on artificial reefs, for example by facilitating invertebrate herbivores.

‘Fish Tales’

The Pacific foodfish list

The sustainable supply of fish in the face of climate change and other drivers of change is a policy priority for Pacific nations. Creel and market surveys are increasingly used to document catches but this information has not been aggregated at a regional scale. In this paper we provide a comprehensive and standardized list of Pacific marine foodfishes in 22 Pacific Island Countriesand Territories to enable comparative analyses and improved national surveys. National lists of marine teleost fish caught for food were cleaned of errors and standardized to current valid names using authoritative global databases. National lists were subsequently aggregated to subregional and regional scales. Pacific people were found to consume more than 1000 species of marine fish (presently 1031 species), with the highest diversity observed in Melanesia and the lowest in Polynesia. A total of 14% of species names have changed since surveys were completed. An estimated 3847 species of marine fish are recorded from the region, most of which are small reef species. This list of Pacific foodfish is available through the Pacific Data Hub curated by the Pacific Community. Conclusions. The study quantifies, for the first time, the great diversity of fishes consumed by Pacific people and highlights the need for more baselines of catch, acquisition and consumption. These findings provide a foundation across the region for analysing species’ relative importance in local economies and diets, supporting fisheries management and food security policies critical to the wellbeing of Pacific people in a changing world.

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Like a fish in water: Habitus adaptation mechanisms of informal tourism entrepreneurs in Thailand.

This article investigates possible pathways of habitus change by informal tourism entrepreneurs in Thailand. Bourdieu's concept of habitus is depicted as a person's understanding of the world. Do people adapt their worldview in response to only external stimuli? Through ethnographic fieldwork including participant observations and active semi-structured interviews with 53 participants, this paper identifies a classification of four modes of habitus adaptation: (1) Understanding and appreciating the field and its conditions, (2) Challenging core beliefs systems, (3) Applying a practical sense to ‘objective possibilities’, and, (4) Challenging non-reflective dispositions. We argue that charting the modes of habitus adaptation could help policymakers understand the change processes of informal entrepreneurs in the tourism sector and their willingness to change.

Cross-secional study to map nutritional quality of meat, fish, and dairy alternatives in Dutch supermarkets according to the Dutch food-based dietary guidelines and nutri-score

Due to a growing challenge to feed the world’s population and an increased awareness to minimize the impact of our food choices on climate change, a more plant-based diet has gained popularity with a growing number of plant-based products on the market. To stimulate a plant-based diet that also improves long-term health, data are needed to monitor whether these products are healthy alternatives to animal-based foods. Therefore, this study inventoried 916 plant-based meat, fish, and dairy alternatives from eight Dutch supermarkets. The nutritional quality of each product was assessed by (1) the Dutch food-based dietary guidelines and (2) the Nutri-Score. The results show that over 70% of meat, fish, and dairy alternatives have an A/B Nutri-Score (indicating high nutritional quality), but do not comply with the Dutch dietary guidelines. This is mainly due to high salt and low vitamin B12 and iron content (meat and fish alternatives) or low protein and calcium levels (dairy alternatives). In conclusion, the majority of plant-based products are nutritionally not full alternatives of the animal-based equivalents; however, there are still opportunities for reformulation. To aid the consumer in making healthy plant-based food choices, a better alignment between the Nutri-Score and the recommended dietary guidelines is needed.