Otolith microstructure analysis was used to reveal daily growth patterns of young-of-the year (YOY) of six species of perciform fishes, Bovichtus chilensis (Bovichtidae), Girella laevifrons and Graus nigra (Kyphosidae), Helcogrammoides chilensis (Tripterygiidae) and Hypsoblennius sordidus and Scartichthys viridis (Blenniidae). YOY collected in intertidal pools from June to December 2008 in Central Chile, ranged from 24 to 76 mm total length and from 25 to 390 days of age. In the six species, sagittal otoliths showed a slightly oval shape, symmetrical and laterally compressed and showed micro-increments distinguishable after a two-side polishing. Increment width of sagittae showed two patterns irrespective of hatch month and species: (i) a parabolic growth with wider increment widths (during the first 150 of YOY life, e.g. B. chilensis, G. nigra and G. laevifrons); and (ii) a more irregular pattern with lower increment widths during most of the seasons in H. chilensis and H. sordidus. Further results were: (i) a unique central primordium enclosed by two checks after which distinctive increments were deposited; (ii) low instantaneous growth rates estimated through the slope of the length-at-age relationship (range 0.1–0.21 mm d−1); and (iii) a linear fish size–otolith size relationship.

The squid Loligo vulgaris has an extended spawning season within the upwelling system off north-west Portugal, and its paralarvae may thus develop under a wide range of environmental conditions. Both temperature and salinity are expected to affect the metabolism of young squid and we tested their effects on growth during the embryonic and post-hatching phase, based on measurements of growth increments in statoliths of juveniles and adults, using generalized additive models. There was no evidence that statolith increments representing early growth become unreadable in adult statoliths. Variability in the statolith size at hatching was weakly but significantly related to the variables in the model. On the other hand, the effects on statolith growth of both sea surface temperature and of sea bottom temperature were significant during early post-hatching life. Thicker increments are deposited in the statoliths of squid living under higher temperatures, which results in summer hatchers having larger statoliths at the age of 90 days. Inspection of the statolith accretion pattern, using a piecewise linear regression method, revealed an ontogenetic shift in increment width, which may be an indication of the age of transition from paralarva to juvenile. On this basis, it is suggested that the planktonic stage lasts 60 or 90 days, depending on whether the paralarvae lived at higher (>15°C) or lower (<15°C) sea surface temperatures. The life strategy under warmer conditions potentially favours survival by reducing the duration of the vulnerable planktonic phase.