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Following the series of articles published on the fish species included in the EU-funded DIVERSIFY project (see April, May, June, July and October issues of International Aquafeed), which ran between 2013 and 2018, we present here the wreckfish (Polyprion americanus), which was the most challenging species in the project. The wreckfish is one of the largest Polyprionidae species, reaching a size of 100kg. It is a deep-water fish (100-to-1000m) found almost throughout the world and is characterised by an extended pelagic juvenile phase (Ball et al., 2000; Sedberry et al., 1999). It is one of the most interesting new species for aquaculture, due to its fast growth (Suquet & La Pomélie, 2002; Rodriguez-Villanueva et al., 2011), late reproductive maturation, high market price and limited fisheries landings and easy handling in captivity with no mortality recorded during the DIVERSIFY trials (Papandroulakis et al., 2008). Its large size makes it appropriate for processing and development of value-added products, which could be of interest for the EU market.

The first wreckfish (Polyprion americanus) juveniles have been produced in Galicia, Spain, after years of research in the reproduction and larval rearing of the species in the framework of the DIVERSIFY project (www.diversifyfish.eu). Early this year, researchers in Vigo, Illa de Arousa, Vilanova de Arousa and A Coruña have finally seen their efforts coming to fruition with the consistent acquisition of large quantities of fertilized eggs after spontaneous tank spawning of their captive reared broodstocks. Given the continuous supply of eggs, the planned research efforts for the development of larval rearing methods have been implemented and the result is a small number of hatchery-produced juvenile wreckfish happily swimming in the tanks of IGAFA and IEO....

Nutritional requirements of wreckfish are unknow so far and there are only a few references related to feeding habitats from commercial caught (Brick Peres & Haimovi, 2003) and feeding rates in captivity (Papandroulakis et al., 2004) . Recently some studies were done about composition of wild wreckfish (Roncarati et al.,2014, Linares et al., 2015). The optimum development of broodstock diets for wreckfish will be essential for the future of the aquaculture of this species. Dietary lipids and specially fatty acids play a critical role in the successful production of high quality gametes and eggs of marine fish (Izquierdo et al., 2001; Sargent et al., 2002). The aim of this work is collecting information about the influence of the feeding of wreckfish broodstock on oocytes composition with the aim of knowing the relationship of broodstock feeding on fecundity and spawn quality., This 5-year-long project (2013-2018) has received funding from the European Union’s Seventh Framework Programme for research, technological development and demonstration (KBBE-2013-07 single stage, GA 603121, DIVERSIFY). The consortium includes 38 partners from 12 European countries –including 9 SMEs, 2 Large Enterprises, 5 professional associations and 1 Consumer NGO- and is coordinated by the Hellenic Center for Marine Research, Greece. Further information may be obtained from the project site at “www.diversifyfish.eu”.

This 5-year-long project (2013-2018) has received funding from the European Union’s Seventh Framework Programme for research, technological development and demonstration (KBBE-2013-07 single stage, GA 603121, DIVERSIFY). The consortium includes 38 partners from 12 European countries –including 9 SMEs, 2 Large Enterprises, 5 professional associations and 1 Consumer NGO- and is coordinated by the Hellenic Center for Marine Research, Greece. Further information may be obtained from the project site at “www.diversifyfish.eu”., One of the priority target within the European project DIVERSIFY is to set the optimal conditions for larval rearing of wreckfish (Polyprion americanus), as well as the development of a general culture protocol that ensures high larval survival. For this reason, the Hellenic Center for Marine Research (HCMR, Greece), Aquarium Finisterrae (MC2, Galicia, NW Spain), Instituto Galego de Formación en Acuicultura (HCMR, NW Spain) and Instituto Español de Oceanografía (IEO, NW Spain) are working with their respective broodstocks, to achieve viable sets and perform experiments commissioned in the project. In this work the first experiments that allowed wreckfish larvae to survive until day 24 of life and to collect growth data, as well as valuable information on larval ontogeny, are described., European Union’s Seventh Framework Programme for research, technological development and demonstration (KBBE-2013-07 single stage, GA 603121, DIVERSIFY).

Within the DIVERSIFY project for the diversification of species in European aquaculture, wreckfish is a special case because of its late sexual maturation, which does not occur until 7-8 years of age (Peleteiro and Brunzón, 2014), besides existing very few data on its reproductive biology because it is a demersal species whose adult specimens tend to live at the range of 100-1000 meters of deep. This work sets out the progress made in the study of the reproductive cycle of this species in stocks established in Galicia (Spain)., European Union’s Seventh Framework Programme for research, technological development and demonstration (KBBE-2013-07 single stage, GA 603121, DIVERSIFY).

Se estudió mensualmente la evolución de la maduración sexual en 3 stocks de cherna (Polyprion americanus) ubicados en Galicia durante los meses de Marzo-Junio. Se obtuvieron muestras de ovocitos mediante canulación, y de esperma por presión abdominal. El análisis del diámetro de los ovocitos muestra que la maduración alcanza su máximo nivel entre finales de abril y mediados de mayo, cuando comienza una leve regresión. En el caso de los machos, la concentración y la movilidad de los espermatozoides del esperma sigue el mismo patrón, sincronizándose con el estado de maduración de las hembras. Estos datos se ajustan a los registros obtenidos en pesquerías naturales para esta especie (Brick y Klippel, 2003). Se estudió mensualmente la evolución de la maduración sexual en 3 stocks de cherna (Polyprion americanus) ubicados en Galicia durante los meses de Marzo-Junio. Se obtuvieron muestras de ovocitos mediante canulación, y de esperma por presión abdominal. El análisis del diámetro de los ovocitos muestra que la maduración alcanza su máximo nivel entre finales de abril y mediados de mayo, cuando comienza una leve regresión. En el caso de los machos, la concentración y la movilidad de los espermatozoides del esperma sigue el mismo patrón, sincronizándose con el estado de maduración de las hembras. Estos datos se ajustan a los registros obtenidos en pesquerías naturales para esta especie (Brick y Klippel, 2003).

The wreckfish (Polyprion americanus) is a much appreciated species from the gastronomic point of view. The renowned quality this fish is well known, both nationally as in the international market. This makes wreckfish a good candidate for marine aquaculture diversification. Preliminary results on the biology (Wakefield et al., 2013) and culture (Peleteiro et al., 2014) of this species suggest that this is a fast grower. Wreckfish also acclimates easily to captivity and handling, and despite their large sizes, no mortality related to handling has been observed. This species readily accepts prepared diets in captivity, and is characterized by its low metabolism and inhabiting great water depths. The present research was designed to obtain information on biochemical composition, biometric parameters, sexual differentiation and maturity of wild caught wreckfish, which are important for a success culture of this species.

One of the selected species for the diversification of traditional marine species is the wreckfish Polyprion americanus due to its growth potential, high larval growth index during its pelagic life phase (Kentouri et al 1995, Papandroulakis et al 1997), the quality of its flesh and its high commercial value. Studies on wreckfish nutritional requirements and optimum diets are missing. There are only a few references related to feeding habitats from commercial caught (Brick Peres & Haimovi, 2003) and feeding rates in captivity (Papandroulakis et al., 2004) . Recently a study about composition of Mediterranean Sea wreckfish was published (Roncarati et al.,2014). The aim of this work is collecting information of the composition of different tissues of wild wreckfish to contribute the development of a specific formulation of a diet for wreckfish broodstock., DIVERSIFY

Senegalese sole (Solea senegalensis) is a species of great interest in aquaculture because it has a high commercial value and a fast development of eggs. The reproduction of Senegalese sole in captivity has been studied since the early 1980s (Rodriguez et al., 1982). While F1 females were shown to be able to produce fertilized eggs from natural spawning as long as they were accompanied by wild males (Mañanos, 2011), failure of F1 males to display normal courtship behaviour has been demonstrated (Carazo et al., 2009). The reason for this failure remains unclear and therefore, research in this subject is paramount to overcome this bottleneck in S. senegalensis culture. We have designed an experiment using two broodstocks maintained since 2010 in the aquaculture facilities of the Oceanographic center of Vigo, one of them (T1) constituted by wild females together with wild and F1 males and the other (T2) constituted by F1 females together with wild and F1 males. One year later we obtained a successful spawn in T2. The main goal of this research was to test whether the male responsible for this spawn was F1.

En las instalaciones de la planta de cultivos marinos del Centro Oceanoqráñco de Vigo (lEO) se cuHivan diversas especies de microaJgas seg1ÍI! sistema tradicional de producción en bolsas (5OOL) y, mayoritariamente; bajo un nuevo sistema de producción en lotobiorreac!ores (FBRs)de columna (1 ooUUd.) de ano rendimiento montados por la empresa AQUALGAE SL. Parte de la producción de microalgas se destina al OJltivoy enriquecimiento de alimento vivo (rotíferos y Artemia). Este experimento se diseñó con el fin de obtener resutados que nos permitan asegurara calidad del cultivo de rotífero, aportando como alimento las microalgas producidas en semicontinuoen los FBRs, para poder así sustituirtotalmenle el sistema tradicional de producción en bolsas, menos productivo, más laborioso y sin apenas control sobre la composición nutricional dela biomasa cosechada. Los resultados obtenidos demuestran la calidad y estabilidad nutricional de las microalgas producidas en los FBRs,11) habiendo dilerencias signilicativas en el crecimiento de las poblaciones de rotíferos, aunque el número total de huevos sí ha sido superior en ~ grupo alimentado con microalgas procedentes de los FBRs. Se discuten además las dilerencias se composición nutricional observadas., In lhe lacilijies 01 lhe Centro Oceanográfico de Vigo (lEO) several species 01 microalgae are produced according to the traditional batch OJltureil poIyelhylene bags (500 L) ando more recently, in high yield column photobiorreactors (PBRs), 100 L each column, installed by tIle ~ AQUALGAE SL. Part 01 lhe harvested microalgae biomass is used lor lhe culture and enrichment 01 live prey (rotiler and Artemia). The goal cíl!e lhis wor1

Durante los últimos años el sistema de cultivo de microalgas marinas ha evolucionado desde los cultivos extensivos y la producción en bolsas de grandes volúmenes para alcanzar la biomasa adecuada, pasando por sistemas de cultivo intensivo en continuo y llegando en la actualidad al uso de un sistema semicontinuo, a base de fotobiorreactores que aprovechando al máximo la luz, consigue alcanzar producciones óptimas en volúmenes y tiempos mucho más reducidos, economizando espacio, tiempo, material e incluso personal. Este experimento consistió en la validación para microalgas de un sistema de valoración y recuento automático de uso veterinario para análisisde esperma (SeA). Los resultados indican que este sistema no sólo es operativo, sino que puede ser de gran utilidad configurando la aplicacitli precisa para el análisis de los parámetros de calidad en el cultivo intensivo de frtoplancton., The marine microalgae conure system has evolved since Ihe beginning 01 aquaculture, where large volumes were produced to attain an adequale biomass, extensive culture, intensive continuous cultures and finally Ihe semi continuous systems Ihat are presently used, using photo bioreactOll, which optimize Ihe use 01 light and nutrients to attain optimal microalgae production in much lower volumes and shorter times, reducing space aIII time required, as well as costs relatedto material and hand labor. The objective 01 this experiment was to validate an automatic sperm count normally used in the veterinary industry (SeA), for rts use in microalgae count. Results indicate that the SeA is valid forthis use. Furthermore, SCAcan be of great utility and accuracy, when configured forthe analysis~ quality parameters in the intensive microalgae culture.

The growth performance and flesh quality of Senegalese sole (Solea senegalensis) fed two practical diets, in which 78% of marine-derived protein was replaced by plant protein ingredients (PP), was compared with those fed a commercial diet (control) from Skretting (57% protein, 18% lipids; dry matter basis). All tested diets were isonitrogenous, but PP diets contained two lipid levels: 9% (PP-9) and 18% (PP-18). PP diets were produced by Sparos S.L. The experiment was conducted in a closed circuit system at the experimental facilities of IGAFA (heated seawater:1930 ).Triplicate groups of 30 pig-tagged fish, born in captivity, with an average weight of 64,09and size16,42were distributed by 9 tanks of 1m2 and fed the experimental diets during 5 months. Analyses of total lipids were carried out. The results were compared by a Studentt-test and one-way ANOVA . By the end of the trial the growth performance of the fish varied significantly among dietary treatments. Fish fed with PP-9 grew better than those fed PP-18, having a final body weight similar to that obtained with the commercial diet (Fig.1). Whole body lipid composition of the fish differed among treatments (Table I). Plant protein diets induced a significantly lower whole body lipid deposition (7-8% ww) than those fed the control (9% ww). This was reflected in lipid distribution among tissues. Lipid levels in the muscle of the commercial fish are significantly higher than in those fed with PP-9. In contrast, the liver lipid content was significantly increased when plant-protein diets were used compared to fish fed the control, confirming previous observation in the pre-fattening phase of sole (Linares et al. WAS2011). Sensory analyses showed that fish from all the tested treatments shared similar texture, odour and taste characteristics. The present results confirm that with low fat diets it is quite feasible to use plant-protein sources without affecting the growth performance or the organoleptic quality of Senegalese sole. Nevertheless, the impact of the increased lipid deposition in liver induced by vegetable sources warrants further studies.

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An artificial fertilization of the Zeus faber was realised by stripping of 2 females and 4 males. Photographs were taken and the principal stages of embryonic and larval development were identified. The eggs were 1.99 ± 0.036 mm of diameter, totally spherical, with a clear and unsculptured eggshell, a narrow perivitelline space and a single oil globule of 0.41 ± 0.014 mm of diameter; incubation was realised to a temperature of 16 ± 0.5 °C and hatching took place on the 11th (176 degrees/day ± 5). The larvae measured 4,3 ± 0,21 mm of length at hatching and were maintained during 20 days to 19,5 ± 0,5 °C. They fed Artemia salina from the fourth day after to hatch (two days after the reabsorption of the yolk-sac). The larvae presented an extensive pigmentation with two typical spots in the dorsal and anal fins; the pigmentation was in increase along the development except in the caudal fin and last vertebral segments and the pelvic fins were shaped large and colourful. The biometric measures indicated an important increase in the height growth whereas the total length increased very slightly for the first days of life.

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Dentro del proyecto “Análisis y estudio de factores de cultivo que condicionan la producción industrial del lenguado senegalés (Solea senegalensis)” financiado por el Plan Nacional JACUMAR, en el año 2006 se adapta a cautividad un lote de reproductores de lenguado senegalés, capturados en aguas gallegas (T-2) compuesto por 65 ejemplares de 950±293.56 g de peso medio y una relación macho/hembra aproximada de 1/1. También se mantiene otro lote de reproductores procedente de cultivo (T-1) compuesto por 100 peces de de 1139±264.44 g de peso medio. Ambos grupos se sometieron a un control de luz atenuada durante el día y a termoperíodo en diente de sierra desde el mes de febrero, obteniéndose respuesta a los 2 meses aproximadamente. Del lote T-2 se obtuvieron puestas viables desde el mes mayo hasta noviembre, en que se volvió al mantenimiento bajo termoperíodo natural. Se obtuvieron 12.6x106 huevos totales y 5.6x106 huevos viables, que dieron lugar a una producción de un millón de larvas. El cultivo larvario se llevó a cabo siguiendo la técnica tradicional de cultivo para esta especie (Cañavate y Fernández-Díaz, 1999), pero rebajando considerablemente los tiempos de utilización de Artemia con el fin de reducir su consumo. La secuencia de alimentación fue: Rotífero: d2-d9, A0: d8-d15, A1-A2: d15-d49 y coalimentación (Artemia+pienso): d22-d50, obteniendo una supervivencia del 45% de peces destetados., Reproduction and larval culture of sole (Solea senegalensis) in Galicia Under the project entitled “Analysis and study of culture factors affecting the industrial production of senegalese sole (Solea senegalensis)”, funded by the JACUMAR National Plan, in 2006, a broodstock senegalese sole was consolidated, caught in Galician waters (T-2), comprising 65 individuals with an average body weight of 950±293.56 g and an approximate male/female ratio of 1/1. Another broodstock from a culture (T-1) was maintained, comprising 100 fish with an average body weight of de 1139±264.44 g. Both stocks were subjected to an attenuated light control during one day and a saw edge thermoperiod control from february, obtaining a response after approximately 2 months. Viable spawns were obtained from batch T-2, from may to november, when the thermoperiod control was cancelled. A total of 12.6x106 eggs were obtained and 5.6x106 viable eggs, which led to the production of a million larvae. Larval culture was conducted following the traditional culture technique for this species (Cañavate y Fernández-Díaz, 1999), but considerably reducing the usage times for Artemia in order to reduce consumption. The feeding sequence was: Rotifer: d2-d9, A0: d8-d15, A1-A2: d15-d49 and cofeeding (Artemia+dry food) d22-d50, obtaining a 45% survival rate among the weaned fish.