Francisco Javier Roo Filgueira Improvements in the production technology of red porgy (Pagrus pagrus) larvae and fry: Las Palmas de Gr an Canar ia - 2009 importance of rearing conditions and diet nutritional value on their quality Improvements intheproductiontechnologyofredporgy( Francisco Ja Las P TESIS DOCT almas de Gr importance ofrearingconditionsanddietnutritionalvalueontheirquality vier RooFilgueira an Canar ia - 2009 ORAL Pagrus pagrus ) larvaeandfry: Index Index................................................................................................................................................I Acknowledgements.......................................................................................................................V List of figures...............................................................................................................................XI List of tables.............................................................................................................................XIV Abbreviations.............................................................................................................................XV Summary.................................................................................................................................XVII 1.-INTRODUCTION.......................................................................................................................1 1.1.-Aquaculture in the world...........................................................................................1 1.2.-Aquaculture in Spain.................................................................................................3 1.2.1.-General aspects..............................................................................................3 1.2.2.-Fry production...............................................................................................4 1.2.3.-Aquaculture in the Canary Islands................................................................5 1.3.-Importance of larval rearing.....................................................................................6 1.3.1.-Larval rearing techniques..............................................................................7 1.3.1.1.-Intensive systems............................................................................8 1.3.1.2.-Extensive systems..........................................................................10 1.3.1.3.-Semi-Intensive (Mesocosms) systems............................................12 1.3.1.3.1.-Natural- bloom...............................................................14 1.3.1.3.2.-Green water method......................................................14 1.3.1.3.3.-Pseudo green water........................................................15 1.3.1.3.4.-Clear water.....................................................................15 1.3.1.3.6.-Neo-greenwater..............................................................15 1.4.-Limiting factors in larval rearing............................................................................16 1.4.1.-Culture conditions related parameters ........................................................16 1.4.1.1.-Larval density................................................................................16 1.4.1.2.-Shape and tank volume.................................................................16 1.4.1.3.-Water renewal...............................................................................17 1.4.1.4.-Use of phytoplankton in the rearing tank................................ ....17 1.4.1.5.-Use of antibiotics..........................................................................18 1.4.2.-Physico-chemical parameters......................................................................18 1.4.2.1.-Temperature.................................................................................19 1.4.2.2.-Salinity..........................................................................................19 1.4.2.3.-Nitrogen excretion products.........................................................20 I Index 1.4.2.4.-Light..............................................................................................20 1.4.3.-Larval feeding and nutrition........................................................................21 1.4.3.1.-Prey density..................................................................................21 1.4.3.2.-Feeding sequence and co-feeding.................................................21 1.4.3.3.-Prey nutritional quality................................................................23 1.4.3.4.-Importance of lipids in the larval nutrition..................................24 1.5.-Problems in marine fish larval rearing..................................................................25 1.5.1.-Larval survival.............................................................................................25 1.5.2.-Incidence of morpho-anatomical disorders.................................................26 1.5.2.1.-Pigmentation anomalies...............................................................27 1.5.2.2.-Skeleton anomalies and factors related to their appearance.......27 1.5.2.2.1.-Environmental factors....................................................31 1.5.2.2.2.-Nutritional factors..........................................................31 1.5.2.2.3.-Genetic factors...............................................................33 2.-OBJECTIVES...........................................................................................................................35 3.-MATERIALS AND METHODS............................................................................................ 37 3.1.-Study localization......................................................................................................37 3.2.-Facilities description ................................................................................................37 3.2.1.-General overview.........................................................................................37 3.2.2.-Larval rearing tanks.....................................................................................40 3.2.2.1.-Tanks of 40.000 litres- Semi-intensive system..............................40 3.2.2.2.-Tanks of 2.000 litres-Intensive system..........................................41 3.2.2.3.-Tanks of 500 litres-Intensive system.............................................42 3.2.2.4.-Tanks of 10.000 litres-Weaning and nursery................................42 3.3.-Studied species..........................................................................................................44 3.3.1.-Habitat.........................................................................................................44 3.3.2.-Geographical distribution............................................................................45 3.3.3.-Aquaculture perspectives.............................................................................45 3.4.-Experimental conditions..........................................................................................46 3.4.1.-Live food cultures.......................................................................................46 3.4.1.1.-Phytoplankton culture..................................................................46 3.4.1.2.-Rotifers culture.............................................................................50 3.4.1.2.1.-Stock maintenance and rotifers pre-culture...................50 II Index 3.4.1.2.2.-Mass culture..................................................................50 3.4.1.2.3.-Rotifers enrichment.......................................................52 3.4.1.3.-Brine shrimp production..............................................................55 3.4.1.3.1.-Hidratation....................................................................55 3.4.1.3.2.-Decapsulation................................................................56 3.4.1.3.3.-Storage..........................................................................57 3.4.1.3.4.-Hatching........................................................................60 3.4.1.3.5.-Enrichment....................................................................60 3.4.2.-Larval rearing..............................................................................................61 3.4.2.1.-Eggs............................................................................................ 61 3.4.2.2.-Semi-intensive larval rearing.......................................................63 3.4.2.3.-Intensive larval rearing.............................................................. 64 3.4.2.4.-Nursery……............................................................................... .67 3.5.-Measurements......................................................................................................... 69 3.5.1.-Growth in length........................................................................................ 69 3.5.2.-Growth in weight....................................................................................... 69 3.5.3.-Survival...................................................................................................... 70 3.5.4.-Histological studies.................................................................................... 71 3.5.5.-Osteological study.....................................................................................