Nucleic acid derived indices or instantaneous growth rate as tools to determine different nutricional condition in cuttlefish (Sepia officinalis, linnaeus 1758) hatchlings

Two groups of 100 cuttlefish hatchlings each were used to determine the duration of the yolk reserves, during which growth can be obtained with no food supply. One group was fed live grass shrimp ad libitum from the 3rd day of life onwards, while the other was starved during the whole experiment. The experiment lasted 7 days, because this was the 1st day where a negative growth rate was obtained. Nucleic acid derived indices and instantaneous growth rates (IGR) were used as a way to describe their condition, when all the yolk reserves would be exhausted and to determine the most accurate tool to express growth and condition. RNA/DNA ratios described clearly the differences (P 0.05) between groups and did not displayed a clear pattern with increasing age. Correlation between IGR and DNA was only attained for the fed population (R −0.90; P 0.0374). RNA concentration values were different from day 5 onwards. Any of the nucleic acid derived indexes were not accurate enough to express growth and condition, so IGR seems to be the most accurate and inexpensive way to describe hatchlings growth and condition in controlled conditions.info:eu-repo/semantics/publishedVersio

Camouflage during movement in the European cuttlefish (Sepia officinalis)

A moving object is considered conspicuous because of the movement itself. When moving from one background to another, even dynamic camouflage experts such as cephalopods should sacrifice their extraordinary camouflage. Therefore, minimizing detection at this stage is crucial and highly beneficial. In this study, we describe a background-matching mechanism during movement, which aids the cuttlefish to downplay its presence throughout movement. In situ behavioural experiments using video and image analysis, revealed a delayed, sigmoidal, colour-changing mechanism during movement of Sepia officinalis across uniform black and grey backgrounds. This is a first important step in understanding dynamic camouflage during movement, and this new behavioural mechanism may be incorporated and applied to any dynamic camouflaging animal or man-made system on the move.info:eu-repo/semantics/publishedVersio

Common octopus (Octopus vulgaris) performance when including fasting on feeding schemes: preliminary data regarding a formulated feed

The common octopus (Octopus vulgaris) has aroused great interest in recent years as a new species for aquaculture. The current research is focused on developing a formulated feed, although a proper diet management has also promoted rearing success of other commercial cultured species. It is documented that wild animals eat depending on prey availability and most experience fasting in nature. Hence, O. vulgaris subadults were subjected to two different feeding schemes, with a similar semi-moist diet, including either 2 (2FDb, control) or 3 (3FDb) non-consecutive days of fasting per week. Growth, feed efficiency (FE), digestibility and condition were assessed after 56 days of rearing. Both feeding schemes promoted similar growth and digestibility (P>0.05), 100% of survival and higher food-intake after fasting. Interestingly, feed efficiency (FE) was enhanced with the 3 fasting days scheme (58.6% vs. 48.3% for 2FDb scheme; P<0.05). Results might indicate that O. vulgaris has the ability to compensate fasting days through an increase in food intake on the subsequent day or a better use of its reserves. Moreover, a reduction on feeding days might promote a decrease in production costs at commercial scale.info:eu-repo/semantics/publishedVersio

Preliminary results on the daily and seasonal rhythms of cuttlefish Sepia officinalis (Linnaeus, 1758) locomotor activity in captivity

Cephalopods are considered as an alternate group for aquaculture species diversification [1,2], not only because they are a good food source (highly appreciated in some worldwide markets, e.g., Portugal, Spain, Italy and Asia) and have the potential to quickly reach a market size, but also because they are considered animal models in several fields of research [3–5], and it is expected that such models are progressively obtained from bioteriums instead of being captured from nature. Despite the recent advances in culture protocols of several cephalopod species [2], there is still little information available about the biological rhythms of cephalopods in captivity. In fact, to the best of our knowledge, there are only 4 published papers concerning this theme, and these are focused on octopus species [6–9]. This issue assumes increasing importance with the enforcement of EU welfare legislation (Directive 2010/63/EU), and this information is critical for the future update of Annex III (housing conditions) for cephalopods of that Directive, and for a future update of the Guidelines for the Care and Welfare of Cephalopods in Research [10]. If it is considered that the European cuttlefish Sepia officinalis (Linnaeus, 1758) may have, at the least, two different sleep‐like states [11], the importance of this study becomes even more evident.info:eu-repo/semantics/publishedVersio

A sensory and nutritional comparison of mussels (Mytilus sp.) produced in NW Iberia and in the Armona offshore production area (Algarve, Portugal)

A biometric, nutritional and sensory analysis of raw and cooked mussels comparing Mytilus sp. from the north-west coast of Portugal and Spain (Minho and Galicia, respectively) and the new offshore production site of Armona (Algarve, south Portugal) was carried out. In addition, multiple factorial analysis was performed to explore potential relationships between sensory attributes and nutritional content properties between the different mussels. Results showed that, at similar times of sale, biometrics of mussels from Armona and Vigo were similar and bigger than the remaining. Nonetheless, despite some similarities in proximate composition, mussels presented differences in lipid classes, fatty acid content and free amino acids profiles. These differences were not fully reflected in the sensory assessment by the panel, which were able to distinguish different production sites in raw specimens but displayed problems in discrimination these in cooked mussels. Some nutritional components were related to specific sensory sensations

Natural geochemical markers reveal environmental history and population connectivity of common cuttlefish in the Atlantic Ocean and Mediterranean Sea

Natural markers (delta C-13 and delta O-18 stable isotopes) in the cuttlebones of the European common cuttlefish (Sepia officinalis) were determined for individuals collected across a substantial portion of their range in the Northeast Atlantic Ocean (NEAO) and Mediterranean Sea. Cuttlebone delta C-13 and delta O-18 were quantified for core and edge material to characterize geochemical signatures associated with early (juvenile) and recent (sub-adult/adult) life-history periods, respectively. Regional shifts in cuttlebone delta C-13 and delta O-18 values were detected across the 12 sites investigated. Individuals collected from sites in the NEAO displayed more enriched delta C-13 and delta O-18 values relative to sites in the Mediterranean Sea, with the latter also showing salient differences in both markers among western, central and eastern collection areas. Classification success based on cuttlebone delta C-13 and delta O-18 values to four geographical regions (NEAO, western, central and eastern Mediterranean Sea) was relatively high, suggesting that environmental conditions in each region were distinct and produced area-specific geochemical signatures on the cuttlebones ofS. officinalis. A modified delta C-13 and delta O-18 baseline was developed from sites proximal to the Strait of Gibraltar in both the NEAO and Mediterranean Sea to assess potential mixing through this corridor. Nearly, all (95%) of delta C-13 and delta O-18 signatures ofS. officinaliscollected in the area of the NEAO closest to the Strait of Gibraltar (Gulf of Cadiz) matched the signatures of specimens collected in the western Mediterranean, signifying potential movement and mixing of individuals through this passageway. This study extends the current application of these geochemical markers for assessing the natal origin and population connectivity of this species and potentially other taxa that inhabit this geographical area.Portuguese Foundation for Science and Technology: IF/00576/2014info:eu-repo/semantics/publishedVersio

Meta‐analysis approach to the effects of live prey on the growth of Octopus vulgaris paralarvae under culture conditions

The common octopus (Octopus vulgaris, Cuvier 1797) is a promising species for aquaculture diversification, but the massive mortality during the first life stage is the main bottleneck for its commercial production. The aim of the present study was to compare the effects of different live preys (Artemia and crustacean zoeae) and/or Artemia enrichment protocols in the paralarval growth by using a meta‐analysis approach. A total of 26 independent assays were used, including data from the bibliography and from experiments carried out by our group. Three comparisons were established: (i) crustacean zoeae vs. Artemia, (ii) different crustacean zoeae species and (iii) Artemia enriched with marine lecithin (rich in polar lipids‐PL and docosahexaenoic acid‐DHA) vs. previously used Artemia enrichments. The meta‐analysis approach allowed a quantitative review of independent studies with reliable conclusions, avoiding the subjectivity inherent to classical reviews. The outputs provided statistical confirmation of the better suitability of crustacean zoeae with respect to Artemia. However, not all crustacean species showed the same results, given that the high variability on Grapsus zoeae hampered finding significant differences with respect to the control treatment (Artemia). Nutrient composition and biometry of the different types of prey are discussed as possible causes of the differences arising from the meta‐analysis. Finally, the present results suggest that marine lecithin has a beneficial effect on paralarval growth with respect to previously used enrichments, which could be related to the increase in DHA and PL in Artemia, given the essential role of these lipid components in octopus paralarval physiology.info:eu-repo/semantics/acceptedVersio

Resolving the ancestry of Austronesian-speaking populations

There are two very different interpretations of the prehistory of Island Southeast Asia (ISEA), with genetic evidence invoked in support of both. The “out-of-Taiwan” model proposes a major Late Holocene expansion of Neolithic Austronesian speakers from Taiwan. An alternative, proposing that Late Glacial/postglacial sea-level rises triggered largely autochthonous dispersals, accounts for some otherwise enigmatic genetic patterns, but fails to explain the Austronesian language dispersal. Combining mitochondrial DNA (mtDNA), Y-chromosome and genome-wide data, we performed the most comprehensive analysis of the region to date, obtaining highly consistent results across all three systems and allowing us to reconcile the models. We infer a primarily common ancestry for Taiwan/ISEA populations established before the Neolithic, but also detected clear signals of two minor Late Holocene migrations, probably representing Neolithic input from both Mainland Southeast Asia and South China, via Taiwan. This latter may therefore have mediated the Austronesian language dispersal, implying small-scale migration and language shift rather than large-scale expansion

Hatchery technologies and nutritional contents of cuttlefish (Sepia officinalis) spawners, eggs, hatchlings and live prey associated

Tese dout., Aquacultura, Universidade do Algarve, 2007A presente tese de doutoramento faz um resumo do estado da arte de cultivo do choco, apresentando uma visão geral acerca do mesmo. Os problemas actuais são identificados e a tese apresenta novos dados e conhecimento relacionados com os mesmos. As técnicas de cultivo, desde o ovo até à fase adulta (Capítulos 1 a 3), são detalhadamente descritas. O uso da camarinha como única presa durante todo o ciclo parece ser adequado enquanto uma dieta artifical não é desenvolvida. O uso de cores escuras nos tanques promoveu o incremento de biomassa e uma diminuição do desvio padrão do peso dos indivíduos.Faculdade de Ciência e Tecnologia( FCT

The effects of temperature in the life cycle of two consecutive generations of the cuttlefish sepia officinalis (Linnaeus, 1758), cultured in the Algarve (south Portugal)

We are presently culturing the 4th generation of the cuttlefish, Sepia offıcinalis in our laboratory. A first generation (F1) was grown from eggs collected from the wild (Ria Formosa – South Portugal) during the summer, at mean temperatures of 27 °C ± 3°. In the present study, a second generation (F2), originated from eggs laid in the laboratory by females from F1 was cultured between the start of autumn and the end of spring, at mean temperatures of 15 °C ± 4 °C. The life cycle of cuttlefish from F2 was compared to F1. Populations of 30 cuttlefish were used in each experiment. Cuttlefish were grown from one day old until the cycle was completed (when the last female in each population had died). Cuttlefish from F2 cultured at much lower temperatures had a longer life cycle, of almost 9 months (260 days) compared to cuttlefish from F1, which completed their cycle in less than 6 months (165 days). Cuttlefish from F2 grew significantly larger (U = 0.00; p < 0.01) with mean weights of 343.3 ± 80.5 g and 248 ± 33.1 g for males and females, respectively, compared to F1 (199.6 ± 40 g and 143.3 ± 30.9 g for males and females, respectively). Females from F2 had higher fecundity (225 eggs female− 1) compared to females from F1 (144 eggs per female−1), produced bigger eggs (t = 45.60752; p < 0.0001), weighing 0.74 ± 0.18 g, compared to 0.46 ± 0.11 from F1, and bigger hatchlings (t = 7,144783; p < 0.0001), weighing 0.10 ± 0.02 g, compared to 0.09 ± 0.02 g for the summer population.info:eu-repo/semantics/publishedVersio