Influence of temperature on the zoeal development and elemental composition of the cancrid crab, Cancer setosus Molina, 1782 from Pacific South America

a r t i c l e i n f o Temperature changes during ENSO cause mass mortalities of adult Cancer setosus, but the effects on early life stages are unknown. The influence of temperature on survival, development and biochemical composition was studied in larvae of the hairy crab, C. setosus, from a population off the northern Chilean coast. In rearing experiments conducted at four different temperatures (12, 16, 20, 22 °C), zoeal development was only completed at 16 and 20 °C, after 78 and 36 days, respectively. Instar duration was negatively correlated with temperature. A multiple linear model relating larval body mass (in carbon) to temperature and developmental time suggests that successful larval development is possible within a narrow temperature range only. The biochemical composition, measured as carbon, hydrogen, and nitrogen (C, H, N) content, show in general the typical oscillating changes during the moult cycle of brachyuran crab larvae. However, at high (22 °C) and low (16 °C) temperatures, CHN values show deviations from the typical pattern, indicating threshold temperatures for larval activity and survival. These findings indicate that the larval development of C. setosus is compromised under conditions of El Niño, with temperatures exceeding the upper thermal temperature tolerance threshold of larvae. Effects of El Niño on early life history stages and recruitment rates should be increasingly taken into account in fisheries management strategies. Most cancrid crabs are found in cold temperate and boreal waters (MacKay, 1943) and provide a huge proportion of crustacean fisheries in those regions (Bennett, 1995; Johnson and Shanks, 2002). Due to their commercial importance population structure and recruitment of cancrid crabs have been the subject of several studies (e. g. Successful recruitment is based on larval development. Larval hatching normally occurs during spring when food availability (plankton bloom) (Park et al., 2007) and temperatures are favourable for larval growth. This seasonal dependency is not valid for larvae in the highly productive upwelling region of the Humboldt Current, which provides a huge amount of plankton year-round during upwelling periods. The persistent stable temperate conditions in a broad range of the Humboldt Current allow larvae to develop all year round (for review see Fischer and Thatje, 2008). As one of the world's most productive ecosystems, the Humboldt Current supports one of the world's largest fisheries (Bertrand et al., 2004) which is of high economical importance for the adjacent countries The availability of resources is …