BUILDING BRIDGES BETWEEN AQUACULTURE AND SCIENTIFIC RESEARCH FOR THE MANAGEMENT OF INVASIVE SPECIES: RED SWAMP CRAYFISH Procambarus clarkii AND RED CLAW CRAYFISH Cherax quadricarinatus IN COSTA RICA

Costa Rica harbors a remarkable native freshwater diversity, including 15 crab species (Pseudothelphusidae) and more than 21 caridean shrimp species (Atyidae and Palaemonidae). Crayfish (Astacoidea) are not part of the Costa Rican native fauna. However, in the 20th century, two crayfish species were introduced: the red swamp crayfish (Procambarus clarkii) in the Cachí reservoir (Reventazón basin, Caribbean slope) and the red claw crayfish (Cherax quadricarinatus) in the Tempisque basin (Pacific slope). Both species were introduced for aquaculture purposes and as alternative protein source. However, the introduction of these species was poorly controlled and the migration to adjacent freshwater systems was not studied. Both crayfish species have been introduced worldwide for aquaculture purposes and have been identified as invasive in most countries. There is broad evidence documenting their negative impact on native species, ecosystem functioning, economy and human health. Despite the potential threat of these crayfish for the Costa Rican freshwater environments, very limited information is available on their occurrence in the country. Therefore, it is necessary to document their current distribution and to assess their possible effects on the ecosystems.

Our project aims to document the presence of these two species in Costa Rican streams and lakes. And to provide information about their ecology in order to develop adequate management strategies. We collected P. clarkii and C. quadricarinatus in several locations outside the original basin where they were introduced, and currently both species are distributed in the Pacific and Caribbean slopes (Fig. 1). The red swamp crayfish feeds mainly on plant material. It remains to be studied whether these species have dispersed naturally or if they were locally introduced and translocated by humans.

We are recently incorporating studies on plastic ingestion, determination of crayfish as vectors for human and crustacean parasites, and new technologies such as environmental DNA to detect crayfish. It is necessary to integrate these efforts with citizen science and collaboration with the aquaculture sector. We are aiming to establish good communication with these groups in order to gather information of the crayfish populations outside the farms, in order to propose management tools for these invasive species in Costa Rica.