World Aquaculture Magazine - September 2021

24 SEP TEMBER 2021 • WORLD AQUACULTURE • WWW.WA S .ORG Acuicultura y Pesca (AUNAP; National Aquaculture and Fisheries Authority), the Centro de Investigación de la Acuicultura de Colombia (CENIACUA; Aquaculture Research Center of Colombia), Benchmark Genetics Colombia, the National Natural Parks of Colombia, in collaboration with the University of Miami. This endeavor resulted in the first successful reproduction of the goliath grouper in captivity in 2015. Since then, continuing research efforts have led to significant progress in closing the aquaculture cycle of this species in captivity. Results obtained in 2015 led to the first production of fingerlings of this species in the world. Fingerlings were raised through juvenile and adult stages and kept in captivity for the following five years until maturity. In 2020, the first filial generation (F1), was subjected to artificial reproduction using hormone induction techniques. Assisted spawning using manual extrusion of gametes (oocytes and sperm) and artificial fertilization techniques were successfully employed and are being further developed and perfected to this day. For the first time, the second generation (F2) of goliath grouper was obtained. This breakthrough represents an important step towards firming up technology development towards commercialization. Since then, this research continues to progress, and results are improving year after year. Spawning and larval rearing activities are currently ongoing in Colombia. Broodstock Management The CEINER infrastructure encompasses large, open-flow net enclosures in the sea, ranging from 2-4 m deep. The enclosures are made by a series of pilings fixed to the seabed built with PVC pipes filled with concrete. These pilings support plastic-coated metal mesh that allows the free circulation of water (Fig. 1). In these enclosures, several species of marine fish from the Colombian Caribbean are kept in semi- captive conditions. Since 1990, CEINER established an initial group of more than 50 goliath grouper broodstock. These large broodstock, ranging in size from 50 to over 150 kg, have been maintained since then in enclosures under natural environmental conditions (Fig. 2). In a first stage, to study their natural reproduction season, submersible pumps with hoses connected to egg collectors were placed in enclosures holding goliath grouper candidate broodstock specimens. Additionally, through direct observation of the specimens and analysis of underwater images, behavior and color changes were recorded to determine and establish the basis for sexual dimorphism, sex ratio, individual dominance and broodstock management in general. Biopsies were also performed on some specimens to determine their sex. The occurrence of natural spawning of this species was determined to be during full moon days in May, for several consecutive years. There have been several natural spawning events observed over the years, but it has not been possible to control or anticipate their activities with any level of certainty. Very few eggs were collected in the enclosures because they were carried away freely by tides and currents. It was established that the behavior and social interaction of sexually mature males and females are extremely complex. At times, they are very aggressive towards each other, regardless of their sex. This causes stress and is likely one of the main reasons for the difficulties in controlling their reproduction and obtaining volitional spawnings in captivity. FIGURE 2. Goliath grouper broodstock maintained at enclosures under natural conditions at CEINER. CEINER — Rosario Islands Oceanario The Center for Research, Education and Recreation (CEINER), commonly called Oceanario Islas del Rosario, is a private entity that is part of the network of zoos and aquariums in Colombia (Fig. 1). It is located on San Martín de Pajarales Island, in the Rosario Islands, 45 km by sea from the city of Cartagena de Indias. CEINER is an organization that provides recreational services and develops research and educational activities to promote and foster understanding and conservation of the life of the tropical seas and in particular of the fauna, flora and environment of the National Natural Park, Corals of Rosario and San Bernardo. CEINER has a collection of typical live animals from the Colombian Caribbean, where dolphins, sharks, sea turtles, pelagic fish, reef fish, marine invertebrates, among others, are kept in their natural environment. CEINER is visited by around 100,000 people a year, including national and foreign tourists, in addition to hosting students and researchers from various universities from Colombia and abroad. CEINER has a marine aquaculture program that carries out basic and applied research on marine resources for the development and adaptation of reproduction and culture techniques of species endemic to the Caribbean Sea of Colombia. The research focuses on species of high ecological and economic importance, aiming at their restocking and conservation. It also conducts research programs towards diversification of aquaculture of shrimp and tilapia in Colombia to provide alternative livelihoods for artisanal fishermen.