Larval development of the subantarctic squat lobster Munida subrugosa (White, 1847) (Anomura: Galatheidae), reared in the laboratory

PATRICIA PEREZBARROS,; SVEN THATJE,; JAVIER CALCAGNO,; GUSTAVO ALEJANDRO LOVRICH

JOURNAL OF EXPERIMENTAL MARINE BIOLOGY AND ECOLOGY

ELSEVIER SCIENCE BV

Año: 2007 p. 35 - 41

0022-0981

The larval development of the squat lobster Munida subrugosa from subantarctic waters of the Beagle Channel (Tierra del Fuego,Argentina) was studied under controlled laboratory conditions of temperature, salinity, and food supply. Developmental times, survival,and growth of larvae and early juveniles were investigated. Hatching of the entire brood always occurred during one night. Larvae werekept in 100ml individual bowls with filtered seawater at 8 ± 0.5°C and fed with Artemia spp. nauplii three times a week. Larvae passedthrough 6 zoeal instars and one megalopa. Previously, only five zoeal instars were known from this species.Mean cumulative durationsof the zoeal stages I toVIwere: 20.5 ± 2.5, 33.9 ± 4.1, 43.3 ± 5.4, 52.6 ± 5, 61.2 ± 3.9, and 83days, respectively. By adding the 28days thata single megalopa took to metamorphose to crab I stage, the complete larval development lasted 111days. Highest mortality occurredprior to the moult fromthe zoea I to zoea II stage (79.21%± 18.65%) and during themoult from zoea VI to megalopa (92.86%).Carapacelength was 1.64 ± 0.06, 1.52 ± 0.16, 1.57 ± 0.26, 1.64 ± 0.21, 2.11 ± 0.35, and 2.58 ± 0.19mm, for zoeal stages I to VI, respectively.Carapace length of megalopae and crab I instars was similar (2.85 ± 0.28 and the 2.84 ± 0.05, respectively). Unlike other subantarcticdecapods, which show a tendency towards abbreviated larval development and/or some degree of endotrophy, M. subrugosa shows anextended planktotrophic larval development synchronized with short seasonal plankton production in austral summers.