A shark tagging programme along the portuguese coast was initiated in 2001 in collaboration with the national marine fisheries service. from a total of 168 blue sharks (prionace glauca) tagged, 34 sharks were recaptured (20% return rate) providing important information on this species' movement patterns for the area. a total of 28 sharks travelled less than 1000 km while at liberty for time periods ranging from 22 to 1294 days. the remaining fish travelled long distances to north-west africa, central atlantic and the bay of biscay. only one shark made a transatlantic migration, being recaptured 3187 km from the tagging site. north–south movements seem to be related to seasonal sea-surface temperature variation in the north-east atlantic. seasonal segregation of different life stages also occurs.

A total of 262 shortfin mako sharks, Isurus oxyrinchus, was sampled from the swordfish longliners operating in the eastern North Atlantic. Most were juveniles, with only 3.4% mature. Based on cohort analysis, average growth was determined as 61.1 cm year⁻¹ for the first year and 40.6 cm year⁻¹ for the second year. There was a marked seasonality in growth, with average monthly rates of 5.0 cm month⁻¹ in summer and 2.1 cm month⁻¹ in winter. Cohort analysis also indicated summer as the probable parturition season, with sharks close to birth size caught in May 2003 and July 2004. Length at maturity for males was estimated at 180‐cm fork length using the Schnute model. No females between 210 and 290‐cm fork length were caught, although this appears to be the interval where maturation occurs. Gear selectivity was considered as the probable cause for the low number of mature females sampled.