Life history traits of Patella candei were studied for the first time, including weight versus length relationship, growth, age structure, sexual maturity, recruitment pattern, mortality rates and yield and biomass-per-recruit of an exploited population in Madeira Island, north-eastern Atlantic using monthly length -frequency data from January to December 1999. The growth pattern of P. candei showed positive allometric nature of growth (b . 3, P , 0.05). The estimated growth parameters showed an asymptotic length (L 1 ) and growth coefficient (K) estimated at 80.81 mm and K at 0.32 year 21 with a growth performance index (w ′ ) calculated as 3.32 based on the collected data. This species is moderately long-lived reaching up to 9.36 years and achieving sexual maturity at 36.7 mm of shell length. The recruitment pattern was continuous, displaying a major peak event per year, occurring in January (25.12%). The estimated total mortality rate (Z) was 1.79 year 21 while natural mortality rate (M) was 0.55 year 21 and fishing mortality rate (F) was 1.24 year 21 . The probability of capture shows that the length at first capture (Lc) was 42.7 mm, the exploitation rate (E) 0.693 and the maximum allowable limit of exploitation (E max ) was 0.779 for the highest yield. The exploitation rate was less than the predicted E max values, showing that the stock of P. candei was found to be under-exploited in the investigated area; however, its slow growth and long life make it extremely vulnerable to over-exploitation.

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The model specification, results and diagnostic tests of generalised additive models (i.e. GAM plots) describing the influence of the amount of each species in the catch, the fishing location, depth and season on the amount of dead discards, slipping and total discards in the Madeiran purse-seine fishery over the 15-month period investigated. Landings of this fishery are mostly composed of blue jack mackerel Trachurus picturatus, Atlantic chub mackerel Scomber colias, and small amounts of sardine Sardina pilchardus.

A total of 49,151 blue jack mackerel, Trachurus picturatus, (Bowdich) was collected in Madeira Island (North‐eastern Atlantic) between 2002 and 2016 to evaluate possible influence of fishing on landings and reproductive parameters. A decreasing trend in the length composition was observed over the study period and length at first maturity decreased by 2.78 cm TL. Maximum yield per recruit decreased from 2002 to 2016 but the corresponding fishing mortality was constant (Fmax = 0.4/year). Considering the fishing mortality level in 2016, it is evident that the stock may be exploited beyond its sustainability limit. Amendments of the purse‐seine fishing regulations and implementation of measures to reduce fishing effort are suggested.

The Atlantic chub mackerel Scomber colias and the blue jack mackerel Trachurus picturatus are two abundant species in the Macaronesia region which includes the archipelago of Madeira, Portugal. Both are key species in the trophic web, being important prey for several local top predators, such as seabirds and marine mammals. Nonetheless, little is known about their feeding ecology in oceanic environments. In this study, the authors describe the seasonal variation in the diet of S. colias and T. picturatus in the oceanic region of Madeira throughout a year. Visual inspection of stomach contents revealed that S. colias fed on a broader range of prey groups than T. picturatus, but for both species, zooplankton (particularly calanoid copepods) and fish were the most important food items. The diet of S. colias included a higher proportion of fish, namely Atlantic saury Scomberesox saurus and S. colias, than that of T. picturatus, that included mostly the longspine snipefish Macroramphosus scolopax. T. picturatus consumed a higher proportion of decapods and other copepods. Seasonal variation was found in the diet of both species, with zooplanktonic species being more important in colder months (February to April) for S. colias and during warm months (May to October) for T. picturatus. Their diet in other seasons was dominated by fish. Although they consume similar prey, carbon and nitrogen stable isotope analysis of muscle of S. colias and T. picturatus showed little overlap in their diets, and T. picturatus showed higher δ15N and a narrower isotopic niche.