Spawning induction, egg quality and larval rearing of meagre (Argyrosomus regius, Asso, 1801) (Teleostei:Perciformes)

• Grant number: 14/03834-2
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate
• Start date: May 01, 2014
• End date: November 30, 2014
• Field of knowledge: Agronomical Sciences - Fishery Resources and Fishery Engineering - Aquaculture
• Principal Investigator: Renata Guimarães Moreira Whitton
• Grantee: Paulo Henrique de Mello
• Supervisor: Constantinos C. Mylonas
• Host Institution: Instituto de Biociências (IB). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Institution abroad: Hellenic Centre for Marine Research (HCMR), Greece
• Associated to the scholarship: 11/12301-0 - Metabolic investigation during the ontogenetic process of dusky grouper larvae (Epinephelus marginatus)( Teleostei: Serranidae), BP.DR

Abstract

Reproduction is one of the events, if not the main, responsible for the maintenance of a species. However, marine fishes when reared in captivity, present some problems in reproduction aspects and females specially present some reproductive dysfunctions such as, fail in complete vitellogenesis process, fail in final oocyte maturation (FOM) and/or ovulation. So, studies on maturation induction therapies using exogenous hormones to stimulate these processes came as an important tool to promote maturation and synchronize the ovulation of the broodstocks. This problem occurs with dusky grouper, Epinephelus marginatus studied in our project, once the females fail to undergo vitellogenesis, FOM and therefore, do not spawn. Actually, the fail of dusky grouper to undergo vitellogenesis in captivity is one of the main impediment of our PhD. project. Another species with this same problem which presents a great potential for aquaculture production in the Mediterranean region is the meagre (Argyrossomus regius), which, with few exceptions, females do not mature in captivity and exogenous hormones need to be used to induce ovulation and spawning. So this species will be the model of the hormonal therapy, egg quality and larval success investigations in HCMR (Hellenic Centre for Marine Research). Besides this fact, we know that overexploitation of marine resources is the main problem of these systems worldwide. So, aquaculture appears as a direct solution for the conservation of marine fish stocks, but some aquaculture fields are still incipient in Brazil. Reproductive aspects such as, spawning induction, egg quality and larval rearing processes are unpredictable for the aquaculture development. So for developing aquaculture sustainability we must have domesticated broodstock which can provide a year-round seed, which could supply aquaculture production and help in stopping overexploitation of marine resources. Studies focusing the hormonal induction especially with GnRHa injections, spawning induction, egg quality and larval rearing are essential to develop aquaculture potential. The development of this project abroad is imperative considering that research projects that focus in solving these reproductive problems are scarce, and with these studies we hope to understand better this process and apply this knowledge in our species. In this sense, studies related to understand these problems and the involved processes are indispensable to boost marine aquaculture, which is an economic area with a great potential in Brazil. So, with these studies we aim to improve our knowledge about reproductive aspects for developing marine aquaculture sustainability, an essential research field for the development of important physiological tools to be applied in Brazilian aquaculture. Finally, HCMR is considered a reference research center in the area of aquaculture, so it is a real honor and a privilege having a positive feedback from Dr. Constantinos C. Mylonas to be accepted for this period in his laboratory. (AU)