Larvae, fry and fingerling quality

Quality control plan Analyse historical production season records to identify weaknesses and develop a quality control plan Improve data records and the flow of information so that you have information on previous production Deformity controls Health and sanitary controls Size variation controls Evaluate requirements for veterinary support, pathology laboratory and training Prepare a manual with all the working procedures/protocols. Standarize production methodology Collect reliable data and analyse to find out what is causing a problem.

Problem identification and resolution strategy for SOP & QC Re-adjustment of production system & protocol / QC schedule (if required) review Data collection (Sampling) Production trial set up Readjustment of protocol / QC schedule Data analysis, discussion & literature review Definition of an existing protocol / QC schedule

Skimmer removing surface films The development of surface skimmers had a tremendous impact on the industry By removing oil films from the water surface larvae were able to gulp air and inflate their swim bladders From slide.

Skeletal deformity due to lack of swim bladders Fish without swim bladders were deformed and un saleable Today 95%+ swim bladder inflation is common and fish are separated flotation in high salinity water while anesthised to remove any remaining individuals without swim bladder. This also provide the opportunity to remove fish with missing or shortened operculum, mouth or other deformities at the same time. J.Sweetman, Ecomarine Ltd. – Tromso 30th October 2001

Role of nutrients in skeletal metabolism in fish (Lall and Lewis McCrea 2007)

Phosphate deficiency

Mouth Operculum Vertebral column Sea bream

Staining method to determine larval deformities: cartilage in blue and bone in red Sea bass Mouth Operculum Vertebral column

Mouth and column deformities in sea bass Operculum deformity in sea bream

Skeletal deformities Pagrus major Bass

Fry quality – deformity, grading and sorting

Collecting fish for grading A number of methods are used to collect fish Bass are more sensitive to handling than sea bream so greater care must be taken. Damaged fish are likely to suffer from myxobacterial infections and stressed fish are likely to succumb to opportunistic pathogens.

Crowding screens Separation and crowding screens can be seen here

Regular nursery grading essential to avoid cannibalism and disease By the time the juveniles bream have reached 2 g it will probably have been size graded 5 times. Apart from the first grading fish are normally handled without the use of anaesthetics but good husbandry practice recommends the use of immunostimulants and/or vitamins in the diet prior to handling or in periods where disease outbreaks are likely. This is essential to avoid cannabalism, ensure even growth rates and subsequently reduce stress. During the last gradings sea bass will be bath vaccinated for Vibrio anguillarum and multivalent vaccines including Pasteurella piscicida are also available.

Bar graders Typical bar graders are most commonly used.

Grading facilities

Fish counters Fish may be counted either by average weight usually allowing a 7% margin for water or through optical electronic counters such as these. The importance of knowing the exact number of fish being moved to the ongrowing site is evident and feeding rates need to be calculated.

Quality control - sorting table Effectively given exceedingly strict marketing criteria and given that deformity may be induced by tank hydrodynamics in many cases the only way to remove minute deformities is through individual inspection. This is done on illuminated glass tables under total anesthesia.

Deformities - Pigmentation

Skeletal deformities Unacceptable – to be discarded

Opercula and swim bladder deformities Unacceptable – to be discarded Acceptable – to be kept

Fin and mouth deformities Unacceptable – to be discarded Acceptable – to be kept