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The larval and post-larval behaviour, growth, colour, and morphology of the brown box crab (Lopholithodes foraminatus) are described for the first time based on laboratory reared animals. A detailed morphological description is provided for 4 zoeal stages, the glaucothoe, and the first crab instar. Selected morphological changes over the remainder of the first year of development are also described. Data are presented on larval growth at 11°C and on zoeal stage durations at approximately 8°C, 12°C and 16°C. While the 4 zoeal stages are planktotrophic, the glaucothoe does not feed; a life history character that has been termed ‘secondary lecithotrophy’. Growth of L. foraminatus larvae and post-larvae is generally similar to that of other North Pacific lithodids with planktotrophic zoeae. Zoeal stage durations decrease with increasing temperature. This relationship levels off at approximately 16°C, a higher temperature than in lithodid species from colder regions. Carapace morphology is suggested as a diagnostic character of larval and post-larval stages of Lopholithodes foraminatus. Secondary lecithotrophy may be widespread or even universal among lithodids and also occurs in pagurid hermit crabs. If the family Lithodidae is indeed nested within the Paguridae, as suggested by recent phylogenetic hypotheses based on molecular evidence, secondary lecithotrophy may be plesiomorphic in lithodids.

The hypothesis that size-selective mortality in the first marine year is a major regulator of recruitment in Pacific salmon Oncorhynchus spp. has led to interest in assessing the recent growth of field-caught fish. Understanding differences in relative growth across years, regions, habitats, and prey fields may provide insights into factors influencing survival. Plasma insulin-like growth factor 1 (IGF1), muscle RNA : DNA ratio (RD), and scale circulus spacing have all been used as indices of recent growth in juvenile salmonids. We concurrently assessed these growth rate indices in a laboratory study of postsmolt, young-of-the-year, ocean-type Chinook Salmon O. tshawytscha. We synthesized results with previous work to inform selection of appropriate growth rate indices for field studies on juvenile salmonids. Muscle samples suitable for RD analysis were obtained nonlethally and without subsequent growth impacts, even for very small juvenile salmon (75-99 mm FL). Plasma IGF1 concentration was strongly correlated with growth rate (R 2 = 0.79), while log e (RD) and mean spacing of the outer two circuli were moderately correlated with growth rate Subject editor: Milo Adkison, University of Alaska-Fairbanks, Juneau

Mutations or environmental factors that result in reversal of conspicuous left-right asymmetries provide an opportunity to study developmental mechanisms. They may also provide insight into evolutionary changes in asymmetry states within and between species. King crabs (family Lithodidae) have a larger right claw and females typically exhibit a dextrally offset abdomen. Nevertheless, I observed a high incidence of left handedness in laboratory reared box crabs (Lopholithodes foraminatus) and captured the first known egg-bearing female lithodid to exhibit reversed asymmetry. This provided a unique opportunity to characterize the reversed phenotype and to compare the incidence of reversed asymmetry in the offspring of normal and reversed females. Asymmetry of the chelae became apparent in the first postzoeal stage (glaucothoe) and handedness was maintained through subsequent instars. Females with larger left claws developed reversed abdominal asymmetry by the fourth crab stage. No reversed asymmetry was observed in the mandibles of zoea larvae or juveniles of either handedness. The incidence of reversed asymmetry in glaucothoe reared from one reversed and three normal females was high (between 20% and 30%), and independent of maternity (P=0.67). Removal of the right cheliped of fourth stage zoeae, and the major cheliped of glaucothoe, did not reverse the direction of asymmetry. Elevated larval rearing temperature also did not affect the frequency of reversed individuals. This lack of evidence for either heritability or induction of handedness is enigmatic. Further investigation of reversed asymmetry in lithodid crabs may provide valuable insights into the development and evolution of bilateral asymmetries.

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