First year growth in the lithodids Lithodes santolla and Paralomis granulosa reared at different temperatures

Abstract

The southern king crab, Lithodes santolla Molina, and stone crab, Paralomis granulosa Jacquinot, inhabit the coldtemperate waters of southernmost South America (southern Chile and Argentina), where stocks of both species are endangered by overfishing. Recent investigations have shown that these crabs show life-cycle adaptations to scarcity of food and low temperatures prevailing in subantarctic regions, including complete lecithotrophy of all larval stages and prolonged periods of brooding and longevity. However, growth and development to maturity are slow under conditions of low temperatures, which may explain the particular vulnerability of subpolar lithodids to fisheries. In the present study, juvenile L. santolla and P. granulosa were individually reared in the laboratory at constant temperatures ranging from 3-15 8C, and rates of survival and development through successive instars were monitored throughout a period of about nine months from hatching. When the experiments were terminated, L. santolla had maximally reached juvenile instar IV (at 6 8C), V (9 8C), or VII (15 8C). In P. granulosa the maximum crab instar reached was II (at 3 8C), V (6 8C), V (9 8C), or VII (15 8C). The intermoult period decreased with increasing temperature, while it increased in successively later instars. In consequence, growth rate showed highly significant differences among temperatures (Pb0.001). Growth-at-moult was highest at 9 8C. Rates of survival decreased significantly in juvenile P. granulosa with increasing temperature. Only at 15 8C in L. santolla, was a significantly enhanced mortality found compared with lower temperatures. Our results indicate that juvenile stages of L. santolla and P. granulosa are well adapted to 5-108C, the range of temperatures typically prevailing in subantarctic marine environments. In spite of causing higher mortality rates, higher rearing temperatures (12-15 8C) should accelerate the rates of growth and maturation, which may be favourable for projects aiming at aquaculture or repopulation of overexploited king crab stocks. D

Infestation of Pseudione tuberculata (Isopoda: Bopyridae) on juveniles of Lithodes santolla (Magellan region, Chile): a spatial mesoscale analysis

“…Some epidemiological features that could be considered typical of the L. santolla and P. tuberculata parasitic relationship are: i) P. tuberculata is an ectoparasite; ii) there is always a female and male parasite per infested juvenile; iii) the parasite seems to produce only sublethal effects on the host and possibly it dies after juveniles migrate to deeper waters; iv) according to previous studies (Lovrich & Tapella, 2014) this seems to be an obligate host-parasite relationship only affecting juvenile stages between 20 to 50 mm CL, and v) based on previous age estimations, parasitized specimens observed in our study are between 3 and 4 years old (Guzmán et al, 2004;Calcagno et al, 2005;Stevens & Jewett, 2014).…”

“…700 km. At this spatial scale we suggest that higher recruitment occurs in areas combining relatively high levels of salinity (>30) subantarctic marine environments (Anger et al, 2004;Calcagno et al, 2005;Cañete et al, 2012). Moreover, we found maximum abundance of recruits near Beagle Channel and Navarino Island, areas typified by low freshwater inputs and high salinity under the influence of the Pacific Ocean (Fig.…”

Distribution, reproductive and energetic conditions of decapod crustaceans along the Scotia Arc (Southern Ocean)

“…In ectotherm invertebrates, temperature is the main exogenous factor which determines the extent of oogenesis and growth (e.g. Bergstrom, 1991;Pearse and Mc Clintock, 1991;Calcagno et al, 2005) and is likely to be responsible for the differences in ovarian development rate and female maturity size between South Georgia and the South Orkney Islands. Differences in reproductive timing of N. antarcticus between the same locations were also reported by Makarov (1970).…”

Temperature-driven biogeography of the deep-sea family Lithodidae (Crustacea: Decapoda: Anomura) in the Southern Ocean

“…Physiological limitations within the Lithodidae mean that larvae will not successfully develop to maturity at temperatures lower than 0-2°C in laboratory experiments (Nakanishi 1981;Shirley and Shirley 1989;Thatje 2004). The speed of growth and development is reduced after even a small decrease in environmental temperature (Kurata 1960;Nakanishi 1985;Anger et al 2003Anger et al , 2004Calcagno et al 2003Calcagno et al , 2005. This can be particularly important for early life stages that are vulnerable to seasonal Xuctuations in food abundance and size-related predation pressures (Holm-Hansen 1985, Thatje 2004.…”