The shortfin mako, Isurus oxyrinchus, is caught in the eastern North Atlantic as a regular bycatch of the surface-drift longline fishery, mainly directed towards swordfish, Xiphias gladius. Stomachs of 112 shortfin mako sharks, ranging in size from 64 cm to 290 cm fork length, showed teleosts to be the principal component of the diet, occurring in 87% of the stomachs and accounting for over 90% of the contents by weight. Crustaceans and cephalopods were also relatively important in this species' diet, whereas other elasmobranchs were only present in lower percentages. Meal overlap was observed in half of the sampled sharks. No clear trend of prey size selectivity was found, despite smaller individuals seeming incapable of pursuing larger and faster prey. The retention of small prey was also observed in the diet of all sizes of shark. Seasonality in food habits was in accordance with the current availability of food items. The observed vacuity index of 12% is comparable to foraging ecology studies using gillnetting and appears not to be influenced by baited longline gear. Morphological relationships of the digestive system might add important information to the foraging ecology studies and to ecosystem modelling.

A study was conducted on a GA(W)-1 wing in order to investigate the effect of testing inverted wings in ground effect at low Reynolds numbers. The wing was tested at a range of ground clearances and Reynolds numbers and results showed that the wing's performance was dependent on both these parameters. Surface flow-visualisation and numerical simulation results highlighted the existence of a laminar separation bubble on the wing's suction surface. The results also indicated that both the bubble's length and the onset of separation were sensitive to ground clearance and Reynolds number. Attempts were made to minimise the wing's Reynolds number dependency by using transition strips on the suction surface. The transition strip results highlighted the influence that a laminar separation bubble has on the overall performance of the wing and how its presence alters the force enhancement and reduction mechanisms on an inverted wing in ground effect.

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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.

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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 ¢sh 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 di¡erent life stages also occurs.

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