Changes in biomass and chemical composition during lecithotrophic larval development of the Southern king crab Lithodes santolla (Molina).

GUSTAVO ALEJANDRO LOVRICH; SVEN THATJE,; JAVIER CALCAGNO,; KLAUS ANGER,; ANTJE KAFFENBERGER,

JOURNAL OF EXPERIMENTAL MARINE BIOLOGY AND ECOLOGY

ELSEVIER SCIENCE BV

Año: 2003 vol. 288 p. 65 - 79

0022-0981

Changes in biomass and elemental composition (dry mass, W; carbon, C; nitrogen, N; hydrogen,H) were studied in the laboratory during complete larval and early juvenile development of thesouthern king crab, Lithodes santolla (Molina), formerly known as Lithodes antarcticus (Jacquinot).At 6F0.5 jC, total larval development from hatching to metamorphosis lasted about 10 weeks,comprising three demersal zoeal stages and a benthic megalopa, with mean stage durations of 4, 7,11 and 47 days, respectively. No differences in development duration or mortality were observed inlarvae either fed with Artemia sp. nauplii or unfed, indicating that all larval stages of L. santolla arelecithotrophic. First feeding and growth were consistently observed immediately after metamorphosisto the first juvenile crab stage. Regardless of the presence or absence of food, W, C, N and Hdecreased throughout larval development. Also the C:N mass ratio decreased significantly, from 7.7at hatching to 4.1 at metamorphosis, indicating that a large initial lipid store remaining from the eggyolk was gradually utilized as an internal energy source, while proteins played a minor role as ametabolic substrate. In total, 56–58% of the initial quantities of C and H present at hatching, and20% of N were lost during nonfeeding larval development to metamorphosis. Nine to ten percent ofthe initially present C, N and H were lost with larval exuviae, half of these losses occurring in thethree zoeal stages combined and another half in the megalopa stage alone. Metabolic biomass degradation accounted for losses of about 47–50% in C and H but for only 10% in N. Hence, mostof the losses in C and H reflected metabolic energy consumption (primarily lipid degradation), whileabout half of the losses in N and two thirds of those in W were due to larval exuviation. Completeindependence from food throughout larval development is based on an enhanced maternal energyinvestment per offspring and on energy-saving mechanisms such as low larval locomotory activityand low exuvial losses. These traits are interpreted as bioenergetic adaptations to food-limitedconditions in Subantarctic regions, where a pronounced seasonality of day length limits the period ofprimary production, while low temperatures enforce a long duration of pelagic development.