INTRODUCTION Trawling –the dragging of nets across the seabed– can be dated back to 1376, when con- cerns and complaints were raised by fishermen about the use of beam trawling (‘a new destruc- tive and wasteful fishing habit’) in England (Roberts 2007). Since then, the introduction of steamed vessels and otter trawls has evolved in the adaptation of trawl fishing technology of many species (Gillett 2008). Furthermore, tech- nological development, market demands and overexploitation of shallow water fishing grounds have led the fishing fleet to progressively explore into deeper waters causing the deep water ecosys- tems to face great threats (Roberts 2002; Morato et al. 2006; Ramírez-Llodra et al. 2011; Norse et al. 2012). Shrimp fisheries have used many types of gears (beach seines, lift nets, cast nets, tramps, etc.), but the otter trawl is currently the most important commercial gear worldwide (Gillett 2008). In recent decades, the concern over the bycatch of the shrimp trawling fisheries has increased signif- icantly (Dumont and D’Incao 2011; Queirolo et al. 2011; Meltzer et al. 2012; Arana et al. 2013; Villalobos-Rojas et al. 2017; Clarke et al. 2018), and the discard rates of these fisheries has MARINE AND FISHERY SCIENCES 33 (1): 95-113 (2020). https://doi.org/10.47193/mafis.3312020061806 MARINE IMPACTS IN THE ANTHROPOCENE HERMIT CRABS ASSOCIATED TO THE SHRIMP BOTTOM-TRAWL FISHERY ALONG THE PACIFIC COAST OF COSTA RICA, CENTRAL AMERICA FRESIA VILLALOBOS-ROJAS 1 , JUAN CARLOS AZOFEIFA-SOLANO 1 , RAQUEL ROMERO-CHAVES 1 and INGO S. WEHRTMANN 1, 2, 3 1 Unidad de Investigación Pesquera y Acuicultura (UNIP), Centro de Investigación en Ciencias del Mar y Limnología (CIMAR), Universidad de Costa Rica, San José, Costa Rica e-mail: v.fresia@gmail.com 2 Escuela de Biología, Universidad de Costa Rica, San José, Costa Rica 3 Museo de Zoología, Escuela de Biología, Universidad de Costa Rica, San José, Costa Rica ABSTRACT. Studies of the bycatch associated to the shrimp trawling fishery in the Pacific coast of Costa Rica do not assess small organisms (< 10 cm TL) and non-dominant species (< 0.1% of total catch). There is a void in assessing the maintenance of the ecology and ecosystem on which the fishery depends. Furthermore, the Constitutional Court of Costa Rica prohibited the renewal of existing and the issuing of new shrimp bottom-trawl licenses, indicating the neces- sity of more scientific information on the impacts of this fishery. We present the results of a 23-month study of the shrimp bottom-trawl fishery, performed between 50 and 350 m deep in the Pacific coast of Costa Rica. A total of 109 hermit crabs were collected (six species and two families). Paguristes cf. holmesi was the most common species. Zone II presented the highest species richness and abundance. Most specimens (81.8%) were caught in shallower waters (50-149 m). More than 45% of the trawls presented hermit crabs. It is imperative to further assess the trawling effects on non-commercial benthic fauna and changes on predator-prey relationships, before issuing new shrimp licenses. Key words: Bycatch, benthos, non-dominant species, deep waters, biodiversity. 95