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  • Preliminary notes on the reproductive biology of the lizardfish, Synodus saurus (Actynopterygii: Synodontidae) in the Azores
    Publication . Sousa, Luis; Barreiros, João P.; Soares, Marta S. C.; Hostim-Silva, Maurício; Santos, Ricardo S.
    Between March and November 2000, 307 specimens of the lizardfish Synodus saurus (Linnaeus 1758) were captured on several coastal areas of Terceira Island, Azores. This species is an important coastal epibenthic predator. Although common, its biology, namely its reproduction, is virtually unknown. During the study period, 206 females (155 mm to 460 mm TL) and 101 males (269 mm to 290 mm TL), were captured. Sex ratio was 2:1 with more males in June. Gonados-somatic Index (GSI) for females and males attained its maximum values during Spring and Summer, showing that these are the most intensive reproduction periods. Hepato-somatic Index (HSI) suggests that this species may well recur on body reserves for energy metabolization in gonad development. Nevertheless, more studies are necessary in order to confirm this assumption. Ovarian histology, presenting different oocytarian phases, indicates that this species has an asynchronous posture. The male increment of June, associated to higher GSI values, suggests that this could represent a moment of intense competition for females, within the studied area.
    2003-03-31Journal article Open access Show more
  • Interannual changes in the diet of the almaco jack Seriola rivoliana (Perciformes: Carangidae) from the Azores
    Publication . Barreiros, João P.; Morato, Telmo; Santos, Ricardo S.; Borba, Alfredo Emílio Silveira de
    The food habits of 232 almaco jack (Seriola rivoliana) were investigated in the Azores (NE Atlantic) between 1997 and 2000. Fish length ranged from 23 to 134 cm (SL), and 83.2% or the stomachs contained food. Their diet was exclusively piscivorous and dominant prey were juveniles or Trachurus picturatus (1997 to 1998) and Scomber japonicus (1999 to 2000). An apparent decrease of T. picturatus stock is interpreted as the main cause for the detected diet shift.
    2003-03-31Journal article Open access Show more