Aquaculture of marine organisms is now the main economic component of China’s marine industry. Among these organisms, fishes and echinoderms take a prominent role because of their nutritional and medicinal value. Although research on economically relevant aquaculture species has been increasing at impressive rates, not much is known on the importance of chemical communication for their reproduction, growth and welfare. Animals use their sense of smell to obtain information about reproductive and social status, gender, and kinship and to find and identify food. However, knowledge about the identity of the compounds (pheromones) that convey reproductive and social information is very limited and largely restricted to some groups such as insects and mammals. In contrast, the identity of pheromones produced by important aquaculture species such as sea cucumbers (Holothuroidea: Echinodermata) and marine fishes is not known, despite strong evidence for their essential function. Recent studies also point out that the chemosensory system and behaviour in several animals including fishes and invertebrates is affected by climate change and in particular ocean acidification.

The main aims of this project are to obtain an insight on the diversity of pheromone systems in two very different organisms of economic value (sea cucumbers and fishes) and to what extent chemosensory perception may be affected by environmental change.

The project brings together teams with complementary knowhow on the physiology of marine mammals: Institute of Science and Environment of the University of Saint Joseph (Macao), the Institute of Oceanology, Chinese Academy of Sciences (Qingdao, China) and the Centre of Marine Sciences of the University of the Algarve (Portugal). 

Natural products have always been of unquestionable importance for the identification of molecules useful for humans. For example, approximately 85% of current diseases are treated with products derived from natural sources . However, considering the great variation among bioactive compounds and the large number of plants, animals, microorganisms and algae species, it is necessary to build up a standard and integrated approach to screen out new compounds that can carry human health benefits. In the past decades, the screening process to identify bioactive compounds, in particular in the pharmaceutical industry, has relied on a brute-force approach where compounds are tested in large numbers without considering the ecology or evolutionary history of the species from which they were extracted. However, the understanding of the species natural histories has been key to traditional approaches that have allowed the selection and use of bioactive compounds for many purposes, even when the underlying mechanisms were unknown. A more efficient approach to identify molecules of interest may thus be to combine modern methods for the characterization and testing of compounds with knowledge on the natural history of species, namely by observing and recording putative bioactivity in nature.

One important source of bioactive compounds in fish is their external mucus. It is produced by specialized cells in the fish epithelium and serves numerous ecological and physiological roles. These include protection against mechanical impact, osmoregulation, protection against chemical toxicants, intraspecific communication, parental feeding and, notoriously, protection against pathogens.

This project aims to explore the functions, mechanisms of action and the bioactive properties of mucus secreted by coastal fish occurring in Macao and in Portugal. The project combines the knowhow in fish physiology and ecology of teams at USJ-ISE, Macao, and ISPA-MARE, Portugal, with the experience in the extraction, isolation and bioactive testing of natural compounds of the team at UCP-CBQF, Portugal. The study will cover species from different families, geographical regions and habitats and will test various bioactive properties with the aim of increasing the potential to identify molecules of interest.

The project aims to study the mechanisms of the stress response in fish framed within the context of domestication. It will focus on two fish species that have undergone domestication processes, the zebrafish Danio rerio and the fighting fish Betta splendens.

The project is a collaboration between the Institute of Science and Environment of the University of Saint Joseph (Macao) and the Instituto Gulbenkian de Ciência (Portugal).