The bigfin reef squid Sepioteuthis lessoniana is a neritic species widely distributed in coastal waters of the Indo-Pacific region and is of interest to fisheries for its high commercial value. Squid samples were collected from Keelung (KL) and Penghu (PH), around northern Taiwan from October 2012 to September 2013. A total of 949 squid were examined, and 620 squid were aged using statoliths. The age range of the squid in KL (55–183 days) was similar to that in PH (77–186 days). The squid hatched almost year-round, except in January and December in KL. Two seasonal cohorts were identified: a spring cohort (hatched in March to May) and an autumn cohort (July to October). Concentrations of nine trace elements in statoliths were analysed using solution-based inductively coupled plasma mass spectrometry (ICP-MS). Significant differences in Fe/Ca, Cu/Ca and Sr/Ca were found between the two locations, while significant differences in concentration ratios of Sr/Ca and Ba/Ca were noted between the two seasonal cohorts. Results of a principal component analysis and cluster analysis varied in life-history traits between the two geographic stocks and in elemental concentrations between the two seasonal cohorts. Squid in KL and PH might undertake different migration routes, while seasonal variability in oceanographic conditions was apparent in the two locations.

The age and growth of Kwangtung skate, Dipturus kwangtungensis, in the waters off northern Taiwan were estimated from 422 specimens collected between July 2006 and July 2008 at the Tashi fishing market in north-eastern Taiwan. The sexes-combined relationship between total length (TL) and centrum diameter (D) was estimated as follows: TL = 14.11D0.888 (N = 411, r 2 = 0.94, P < 0.001). Growth band pairs (comprised of translucent and opaque bands) in vertebrae were determined to form once annually, based on the centrum edge analysis. Up to 14 band pairs were found for both sexes. The von Bertalanffy growth function (VBGF), two-parameter VBGF, the Robertson function, and the Gompertz function were used to fit the observed length-at-age data. The Akaike information criterion corrected indicated that the Gompertz function best fit the observed length at age data. Sex-specific growth functions were not significantly different; the sexes-combined growth parameters were estimated as follows: asymptotic length (L ∞ ) = 96.7 cm TL, growth coefficient (k G) = 0.144 year−1 and constant (t 0) = 5.45 year (N = 364, P < 0.01).