Skeletal anomalies in dusky grouper Epinephelus marginatus (Lowe 1834) juveniles reared with different methodologies and larval densities

Abstract

This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.A C C E P T E D M A N U S C R I P T Skeletal anomalies in reared dusky grouper juveniles ACCEPTED MANUSCRIPTThe first attempts to reproduce dusky grouper (Epinephelus marginatus, Lowe 1834) under controlled conditions started in 1995, but the egg and larvae quality was very low. Mass production is still encountering many difficulties, mainly concentrated in the larval period when very high mortality rates are observed, confirming what has been observed in the rearing of other grouper species. The main bottlenecks have been identified as the difficulty to properly nourish the larvae, stress shock syndrome, and the high deformation rates.We analysed 633 dusky grouper larvae and juveniles (0.2-7.2 cm total length, TL), sampled during two larval rearing cycles carried out in 2001 and 2002 in Italy. The specimens at different development stages were stained in toto for bone and cartilage and examined for skeletal anomalies during dusky grouper ontogenesis. The incidence of anomalies in groupers hatched from the same egg batch but reared using two different methods (green waters and semi-intensive rearing) and three stocking densities (8, 16 and 28 larvae/l) was compared, with a view to providing tools for identifying the most appropriate larval rearing method in order to at least limit the onset of skeletal anomalies.Our results suggest that during development no particular skeletal anomaly patterns (or fate) can be clearly identified as a high variability was observed in malformation typologies and the regions affected.No significant differences in the morphological quality between groupers reared using semi-intensive (LV02 lot) and green water (GW02-01 lot) methodologies were observed, whilst groupers reared at the highest stocking density (28 larvae/l) showed the highest frequency of deformed individuals (75.8%), the highest malformation charge (average of 5.5 anomalies per deformed individual), the largest range of anomaly typologies (38), and the highest incidence of individuals with at least one severe anomaly (30.9%). Whilst in green waters no evident effects of larvae density were observed on survival rates, the survival rate in large volume reared individuals (17.5%) was considerably higher with respect to those reared in green waters (0.2%) at 7-8 larvae/litre. This indicates that the semi-intensive methodology should be considered more effective in enhancing the survival rate of dusky grouper larvae.

The effect of feeding frequency, water temperature, and stocking density on the growth of river puffer Takifugu obscurus reared in a zero-exchange water system

“…It may be for the reason that tiger puffer has more interspecific aggression than river puffer. Meanwhile, previous studies have reported that stocking density affected skeletal anomalies (Boglione et al 2009), metamorphosis (Hosfeld et al 2009), sex ratios (Saillant et al 2003), gonad development Claudia et al 2004, egg production (Peck andHolste 2006), skin pigmentation (Doolan et al 2008), and survival (Tagawa et al 2004) on various fishes.…”

Malformaciones craneales en larvas y juveniles de peces cultivados

“…De esta forma, modificando las condiciones de luz junto con el uso de la técnica de cultivo de aguas verdes (adición de microalgas a los sistemas) puede reducir este comportamiento (Bristow & Summerfelt, 1994;Cobcroft & Battaglene, 2009). Sin embargo, en Epinephelus marginatus se ha demostrado, que ni la reducción de las densidades de cultivo o diferentes metodologías utilizadas (aguas verdes) parecen tener efecto sobre la incidencia y tipología de malformaciones, requiriéndose más estudios sobre las causas de las malformaciones en esta especie (Boglione et al, 2009). Los juveniles de D. labrax exhibieron un alto nivel de malformación (81%) probablemente debido a la intensa actividad natatoria de los peces durante el crecimiento (Bardon et al, 2009).…”

Skeletal Development and Mineralization Pattern of the Vertebral Column, Dorsal, Anal and Caudal Fin Complex in Seriola Rivoliana (Valenciennes, 1833) Larvae

“…Also, the caudal skeleton development of the S. lalandi has been reported [29]. In addition, numerous studies have described the osteological development of other marine finfish species, such as Sparus aurata [30,31], Pagrus pagrus [32,33], Solea senegalensis [34,35], Dentex dentex [36], Argyrosomus regius [37], Epinephelus septemfasciatus [38] or Dicentrarchus labrax [39].…”