STECF Fisheries Dependent Information – FDI (STECF-19-11)

Commission Decision of 25 February 2016 setting up a Scientific, Technical and Economic Committee for Fisheries, C(2016) 1084, OJ C 74, 26.2.2016, p. 4–10. The Commission may consult the group on any matter relating to marine and fisheries biology, fishing gear technology, fisheries economics, fisheries governance, ecosystem effects of fisheries, aquaculture or similar disciplines. The STECF reviewed the report of the EWG on Fisheries-dependent Information during its winter 2019 plenary meeting

Un meta-análisis sobre el crecimiento de las paralarvas de pulpo común (Octopus vulgaris) alimentadas con diferentes presas vivas

El objetivo del presente estudio fue comparar el efecto de la alimentación con diferentes presas vivas (Artemia y zoeas de crustáceos) y/o Artemia enriquecida, sobre el crecimiento de paralarvas de pulpo común (Octopus vulgaris) a través de un meta-análisis. Se usaron un total de 26 ensayos independientes para analizar las diferencias en crecimiento entre: (i) zoeas de crustáceos vs Artemia, (ii) diferentes especies de crustáceos y (iii) Artemia enriquecida con fosfolípidos marinos vs otros enriquecedores de Artemia. Se observó un mejor crecimiento de las paralarvas alimentadas con zoeas de crustáceos vs Artemia. Sin embargo, no todas las zoeas mostraron los mismos resultados, dada la alta variabilidad observada con el género Grapsus que impidió que se pudieran apreciar diferencias respecto a la Artemia usada como control. Finalmente, el enriquecimiento de Artemia con fosfolípidos marinos mejoró el crecimiento de las paralarvas, lo cual podría estar relacionado con el incremento en los niveles del ácido docosahexaenoico ((DHA, 22:6n-3) y de los lípidos polares en Artemia

Preliminary Results on Light Conditions Manipulation in Octopus vulgaris (Cuvier, 1797) Paralarval Rearing.

High paralarvae mortality is a major bottleneck currently hindering the control over the lifecycle of common octopus (Octopus vulgaris Cuvier, 1797). It is believed that this problem might be related to either zoo-technical and/or nutritional aspects. The present paper is focused on the study of different zoo-technical aspects related to light conditions on the rearing of paralarvae, including the effects of polarization in prey ingestion, the use of a blue filter to simulate natural conditions, and the use of focused light to avoid reflections of the rearing tank’s walls. In the first experiment, O. vulgaris paralarvae ingestion of Artemia sp. and copepods (Tisbe sp.) was assessed under either normal or polarized light. In the second experiment, the effect of a blue filter with natural light or focused artificial light on growth and mortality was assessed over 15 days of rearing. Ingestion rate was not influenced by light polarization. Nonetheless, a significantly higher ingestion of Artemia sp. with respect to copepods was observed. The blue filter promoted the use of natural light conditions in Octopus paralarval culture, while focused light reduced the collision of the paralarvae against the walls. However, no significant differences were found in paralarval growth nor survival

Effect of Artemia inherent fatty acid metabolism on the bioavailability of

The aim of the present study was to determine the effect of Artemia metanauplii endogenous fatty acid (FA) metabolism in the actual availability of dietary essential fatty acids (EFA) for Octopus vulgaris paralarvae development. To this end, both Artemia metanauplii inherent radiolabelled FA metabolism and the Octopus vulgaris paralarvae FA metabolism, after being fed with Artemia metanauplii incubated with radiolabelled FAs, were determined. Metanauplii were incubated in tissue culture plates during 12 h, with 0.3 μM of a [1-14C]FA, including either 18:3n-3, 20:4n-6 (ARA), 20:5n-3 (EPA) or 22:6n-3 (DHA), added individually to separate wells as their potassium salts bound to bovine serum albumin. A total of 3600 one-day-old paralarvae were reared up to 24 h in order to ensure the ingestion of a minimum amount of the labelled Artemia. Paralarvae rearing was performed in 4 L cylinder conical tanks at a density of 25 paralarvae L−1. Labelled Artemia metanauplii were added to each paralarvae rearing tank according to a specific [1-14C]FA treatment. Artemia in vivo metabolism results showed a preferential catabolism of DHA, which was translated into (1) the lower incorporation of this FA into Artemia total lipids (TL); (2) the highest amount of de novo synthesis of shorter chain-length FAs, as a result of the β-oxidation of the original DHA substrate. The registered amounts of radiolabelled substrates incorporated into O. vulgaris paralarvae TL fed with labelled Artemia metanauplii were extremely low. Nonetheless, certain amount of intact [1-14C]ARA and [1-14C]EPA was recovered into octopus paralarvae TL and particularly into polar lipid classes, suggesting the possibility of using Artemia as a vehicle to provide ARA and EPA to octopus paralarvae without interfering their bioavailability for the de novo synthesis of phospholipids. On the other hand, and despite of the high amount of [1-14C]18:3n-3 incorporated into Artemia TL, the FAs with the highest esterification rate into Artemia TAG (18:3n-3 and DHA) were also the lowest incorporated into paralarvae TL. Therefore, the present results suggest that O. vulgaris paralarvae may have a potentially low capacity to metabolise dietary TAG, and so, Artemia may not be the most appropriate vehicle to provide DHA to paralarvae

Comparative study on fatty acid metabolism of early stages of two crustacean species: Artemia sp. metanauplii and Grapsus adscensionis zoeae, as live prey for marine animals.

The present study compared the lipid composition and in vivo capability of Artemia sp. metanauplii (the main live prey used in aquaculture) and Grapsus adscensionis zoeae (as a wild zooplankton model) to metabolise unsaturated fatty acids. The two species were incubated in vivo with 0.3 μM of individual [1-14C]fatty acids (FA) including 18:1n‐9, 18:2n‐6, 18:3n‐3, 20:4n‐6 (ARA), 20:5n‐3 (EPA) and 22:6n‐3 (DHA) bound to bovine serum albumin (BSA). Compared to metanauplii, zoeae contained twice the content of polar lipids (PL) and eight-fold the content of long-chain polyunsaturated fatty acids (LC-PUFA). Artemia sp. metanauplii showed increased short chain fatty acid de novo synthesis from beta-oxidation of [1-14C]LC-PUFA, preferentially DHA. Of the LC-PUFA, DHA showed the highest esterification rate into Artemia sp. triacylglycerols. In contrast, in Grapsus zoeae [1-14C]DHA displayed the highest transformation rate into longer chain-length FAs and was preferentially esterified into PL. EPA and ARA, tended to be more easily incorporated and/or retained than DHA in Artemia sp. Moreover, both EPA and ARA were preferentially esterified into Artemia PL, which theoretically would favour their bioavailability to the larvae. In addition to the inherent better nutritional value of Grapsus zoeae due to their intrinsic lipid composition, the changes taking place after the lipid incorporation, point at two distinct models of lipid metabolism that indicate zoeae as a more suitable prey than Artemia sp. for the feeding of marine animal