Costa Rican Scientists Revive Fish Larvae Research to Protect Fisheries

Costa Rican scientists and marine conservation specialists are working to revive an important field of research that could help protect fish populations and improve the sustainable management of marine resources. The Costa Rican Fishing Federation (FECOP), in collaboration with the University of Costa Rica’s (UCR) School of Biology and Center for Research in Marine Sciences and Limnology (CIMAR), organized an intensive course on ichthyoplankton in the Eastern Tropical Pacific. The five-day training brought together 18 participants from universities in Costa Rica, Colombia, and Panama, as well as officials from the Costa Rican Fisheries and Aquaculture Institute (Incopesca). Ichthyoplankton refers to fish eggs and larvae, whose study provides valuable information about marine species’ reproduction, distribution, and population dynamics. Participants attended theoretical sessions and laboratory exercises, using stereomicroscopes to identify eggs and larvae, distinguish their developmental stages, and analyze ecological and oceanographic data. Johel Chaves, a FECOP research scientist, explained that many marine species reproduce in areas far from where they spend their adult lives. “To protect fish populations, it is not enough to know where they live during their adult lives. It is also essential to identify where they reproduce, how their eggs and larvae develop, and what environmental conditions favor their survival,” he said. Chaves highlighted the king shad, an important species for Costa Rica’s recreational and sport fishing industry. Although it inhabits coastal and freshwater environments, it reproduces in the ocean. Its eggs and larvae depend heavily on ocean currents to reach coastal and freshwater habitats, where they undergo further development. Understanding these movements can help scientists identify spawning grounds and determine which environmental conditions are necessary for fish populations to replenish themselves. The initiative also seeks to revive research pioneered at UCR during the 1980s by scientist Myrna López, whose work produced an extensive collection of specimens and information on fish development. However, following her retirement around 2018, research focused on identifying ichthyoplankton in Costa Rica was discontinued. FECOP’s renewed interest emerged during oceanographic investigations associated with NASA’s PACE satellite mission. These studies examine ocean color and phytoplankton, which form the foundation of marine food webs. During research expeditions, scientists collected plankton samples, including fish eggs and larvae, creating a need for specialized identification expertise. FECOP subsequently collaborated with Colombian marine biologist Beatriz Beltrán León, who has more than 30 years of experience studying ichthyoplankton. That partnership inspired the intensive training program, aimed at preparing a new generation of researchers. FECOP hopes the collaboration will lead to additional scientific projects, strengthen marine conservation efforts, and support more sustainable fisheries management in Costa Rica.