Untitled

Funder

Organizational Unit

Publications

Fecundity and sex steroid profile in boarfish Capros aper

Publication . Sequeira, Vera; Couto, Elsa; Neves, Ana; Vieira, Ana Rita; Canario, Adelino; Gordo, Leonel Serrano

The boarfish Capros aper is one of the most commonly discarded non-commercial species in the International Council for the Exploration of the Sea (ICES) Subdivision VIII in the Atlantic. An increasing interest in this fishery and an incomplete knowledge on the status of the stock justified the present investigation focused on the determination of fecundity type and its estimation, supported by sex steroid profiles for 17 beta-oestradiol (E2), 11-ketotestosterone and 17,20 beta-dihydroxypregn-4-en-3-one (17,20 beta-P). C. aper was found to have indeterminate fecundity with a mean relative batch fecundity during the spawning peak of 50 oocytes g(-1) eviscerated weight (W-E) and a mean relative annual fecundity of 4020 oocytes g(-1) W-E. E2 variations throughout the year indicated the existence of at least two important spawning events, one in winter (January-February) and the other in summer (June-August), with concentrations in females increasing from those with growing oocytes in the developing phase to those in the spawning capable phase. Higher E2 concentrations were also found from 2000 to 2400 hours and from 0800 to 1200 hours suggesting more intense vitellogenesis activity during the night and in the morning, in contrast to 17,20 beta-P concentrations, which were higher between 1200 and 2000 hours, suggesting a more intense spawning activity during this period.

2021Journal article

Open Access

Comparative ontogeny of the digestive tract of Oncorhynchus mykiss female x Salmo trutta caspius male triploid hybrids to their parental species

Publication . Najafpour, Babak; Dorafshan, Salar; Paykan Heyrati, Fatemeh; Canario, Adelino; Power, Deborah

the ontogeny of the gastrointestinal tract of the hybrid between female rainbow trout, RT (Oncorhynchus mykiss) and male Caspian brown trout, CBT (Salmo trutta caspius) was compared to the parental species. Larvae were collected for histology and enzymatic assays (amylase, lipase and trypsin) at 3, 6, 9, 12, 15, 18, 21, 26, 31, 35, 40 and 45 days post-hatch (dph). the development of the gastrointestinal tract (GI-tract) and the onset of digestive enzyme production was variable between groups. the GI-tract post-hatch was a relatively simple tubular structure, and a rudimentary oesophagus was differentiated from other regions at 3 dph in all studied groups. the pyloric caeca and the U-shaped stomach were clearly visible at 26, 35 and 40 dph in RT, triploid hybrid and CBT, respectively. An abrupt increase in trypsin activity at 31, 35 and 45 dph was identified in CBT, RT and the triploid hybrid, respectively. the increasing activity of trypsin and decreasing activity of lipase during larval development suggests that the CBT, RT and triploid hybrid rely more on dietary proteins than lipids with increasing age. the hybrid grew better and had a faster GI-tract development than CBT, while RT performed best overall.

2021-04Journal article

Open Access

The Late Pleistocene-Holocene sedimentary evolution of the Sines Contourite Drift (SW Portuguese Margin): A multiproxy approach

Publication . Teixeira, Manuel; Terrinha, Pedro; Roque, Cristina; Voelker, Antje; Silva, Pedro; Salgueiro, Emilia; Abrantes, Fatima; Naughton, Filipa; Mena, Anxo; Ercilla, Gemma; Casas, David

2020-09Journal article

Restricted

Different sensitivity to heatwaves across the life cycle of fish reflects phenotypic adaptation to environmental niche

Publication . Madeira, Diana; Madeira, Carolina; Costa, Pedro M.; Vinagre, Catarina; Portner, Hans-Otto; Diniz, Mario S.

Predicting responses of marine organisms to global change requires eco-physiological assessments across the complex life cycles of species. Here, we experimentally tested the vulnerability of a demersal temperate fish (Sparus aurata) to long-lasting heatwaves, on larval , juvenile and adult life-stages. Fish were exposed to simulated coastal (18 degrees C), estuarine (24 degrees C) summer temperatures, and heatwave conditions (30 degrees C) and their physiological responses were assessed based on cellular stress response biomarkers (heat shock protein 70 kDa, ubiquitin, antioxidant enzymes, lipid peroxidation) and phenotypic measures (histopathology, condition and mortality). Life-stage vulnerability can be ranked as larvae > adults > juveniles, based on mortality , tissue pathology and the capacity to employ cellular stress responses, reflecting the different environmental niches of each life stage. While larvae lacked acclimation capacity, which resulted in damage to tissues and elevated mortality, juveniles coped well with elevated temperature. the rapid induction of cytoprotective proteins maintained the integrity of vital organs in juveniles, suggesting adaptive phenotypic plasticity in coastal and estuarine waters. Adults displayed lower plasticity to heatwaves as they transition to deeper habitats for maturation, showing tissue damage in brain, liver and muscle. Life cycle closure of sea breams in coastal habitats will therefore be determined by larval and adult stages.

2020-12Journal article

Restricted

Effect of temperature on growth, photosynthesis and biochemical composition of Nannochloropsis oceanica, grown outdoors in tubular photobioreactors

Publication . Carneiro, M.; Cicchi, B.; Maia, I. B.; Pereira, H.; Zittelli, G. Chini; Varela, João; Xavier Malcata, F.; Torzillo, G.

Since temperature is an important factor affecting microalgal growth, photosynthetic rate and biomass composition, this study has accordingly focused on its effects on biomass yield and nighttime biomass loss, as well as photochemical changes, using Nannochloropsis oceanica as model species, grown in two outdoor 50-L tubular photobioreactors (PBR). In two independent trials, cultures were subjected to a diurnal light:dark cycle, under a constant temperature of 28 degrees C and, on the second trial, at 18 degrees C. Changes in culture performance were assessed by measuring growth, lipid and fatty acid composition of the biomass in both morning and evening. Our results revealed that N. oceanica shows a wide temperature tolerance with relevant nighttime biomass loss, that decreased at lower temperatures, at the expenses of its daily productivity. Fluorescence measurements revealed reversible damage to photosystem II in cells growing in the PBR under optimal thermal conditions, whereas microalgae grown at suboptimal ones exhibited an overall lower photosynthetic activity. Lipids were partially consumed overnight to support cell division and provide maintenance energy. Eicosapentaenoic acid (EPA) catabolism reached a maximum after the dark period, as opposed to their saturated counterparts; whereas lower temperatures led to higher EPA content which reached the maximum in the morning. These findings are relevant for the production of Nannochloropsis at industrial scale.

2020-08Journal article

Open Access