Life History, Knowledge, Bottlenecks, and Challenges for the Aquaculture of Concholepas concholepas (Gastropoda: Muricidae) in Chile

Abstract

The carnivorous keystone muricid species Concholepas concholepas (Bruguiere, 1789) is known in Chile as “loco,” in Peru as “pata de burro, tolina, or chanque,” and in internationalmarkets as “false abalone.” The loco is present along the coast of Chile, in theArchipelago of Juan Fernandez and in southern and central Peru, and its range of distribution spans over 5,000 km of intertidal and shallow subtidal reefs. In Chile, the loco is a traditional food resource and has been heavily exploited since the early Holocene by intertidal food-gathers and free divers, and since the 1950s/60s by a small-scale artisan fleet of hookah-divers. In Chile, since the mid-1970s, the species has been mainly exported (foot-meat) to Asian markets, and between 1976 and 1980 market demands acted as a major driving force behind overexploitation of the loco. Since the 1990s, its fishery moved from an open access regime to a comanagement regulated policy based on territorial user rights for fisheries (TURF) and reproductive fishery bans. The loco, as an iconic species, played a key role in the implementation of TURF. In Peru, the loco fishery operates under a reproductive ban fishery regime and its export started in the late 1990s. In Chile, the loco is by far the most intensely studied of all exploited shellfishes in terms of evolution, paleobiogeography, biogeography, life history, behavior, physiology, ecology, genetics, and fishery. Moreover, the loco has been used as a biological model to study responses to global stressors such as ocean warming and acidification. During the past 20 y, several laboratory experimental attempts have been made to advance experimental, pilot, and commercial aquaculture of the loco. Nevertheless, the available information shows that no reliable and repeatable pilot or massive aquaculture protocols have yet succeeded. In this study, the extensive field and laboratory information for the most relevant life history phases of the loco, such as reproduction, mating, brood-stock holding, egg capsule deposition, larval posthatching, growing to competence, larval feeding, settlement and metamorphosis to juvenile stages, and pilot growing experiences to adult sizes are reviewed. In light of the available information, the most critical aquaculture bottlenecks are identified. Among them, the existence, from hatching to competence, of a long larval planktonic phase of about 3–4 mo, and the existence of cannibalism during postsettlement confined laboratory conditions are highlighted. Moreover, key aspects of the larval rearing of the loco, such as densities, field and laboratory food items, and temperatures are reported. The field collection of (1) competent larvae of locos in inshore coastal plankton; (2) new settlers from rocky shores; and (3) new settlers from fishery-discarded conspecific shells are also discussed. The collection of competent larvae was followed by laboratory induction to settlement and by two consecutive postsettlement rearing/growing phases (laboratory and field conditions) to overcome difficulties associated with the long larval phase and to speed up the time required to reach trading sizes. Furthermore, collection of new settlers was followed by rearing experiments under both laboratory and field conditions. The need of high demands of live prey (mainly mussels) during the laboratory rearing of the early benthic stages of loco is discussed, emphasizing that to implement ecologically sustainable aquaculture practices, parallel aquaculture of the appropriated prey is needed. A review of what is already known regarding the biology of C. concholepas is provided along with progress and pit-falls for the aquaculture of this species. The practicality for its aquaculture and the main challenges ahead are also discussed.