Vulnerabilities in aquatic animal production.

The role of aquatic animals in global food and nutrition security is increasingly recognised. The global demand for fish is increasing, leading to a need to significantly increase its supply. Securing future fish supplies through sustainable production is a challenge as major resources such as fresh water and land are becoming limited worldwide. Aquaculture and capture fisheries face various threats from both human-mediated and natural environmental change, including climate change. Aquaculture systems and practices are vulnerable to such changes. Moreover, aquatic animal diseases are currently considered one of the most important constraints to sustainable global fish production. The need to increase global production, combined with climate change, may increase losses due to diseases. This paper examines key vulnerabilities, their impacts and management to achieve increased and sustainable global fish production. The authors focus on the need to apply international standards, and to develop biosecurity and capacity in aquatic animal health to improve global fish health. Research needed to underpin the development of improved detection and control of fish diseases is also discussed.

L'importance des animaux aquatiques pour la sécurité alimentaire et nutritionnelle mondiale est désormais reconnue. La demande mondiale en aliments issus d'animaux aquatiques ne cessant d'augmenter, il est devenu impératif de renforcer significativement l'offre du secteur. La sécurisation future de cette offre grâce à la mise en place d'une production durable constitue un défi de taille en raison de la raréfaction de certaines ressources cruciales, dont l'eau douce et les terres. L'aquaculture et la pêche de capture font face à plusieurs menaces induites par les transformations tant naturelles qu'anthropiques subies par l'environnement, y compris le changement climatique. Les systèmes et les pratiques de l'aquaculture présentent des vulnérabilités à ces changements. De plus, on considère aujourd'hui que les maladies des animaux aquatiques constituent l'une des principales entraves à une production aquacole durable au niveau mondial. Les pertes dues aux maladies vont probablement augmenter par l'effet conjoint du changement climatique et de la nécessité d'accroître les quantités produites dans le monde. Les auteurs examinent les principales vulnérabilités à l'œuvre ainsi que leur impact et les manières d'y faire face en vue d'une production aquacole mondiale accrue et durable. Ils mettent l'accent sur la nécessité de se conformer aux normes internationales et de renforcer la biosécurité et les capacités du secteur de la santé des animaux aquatiques afin d'améliorer le statut sanitaire de ces animaux à l'échelle mondiale. Ils font également le point sur les travaux de recherche qu'il convient de mener afin de mettre au point de meilleures méthodes de détection et de contrôle des maladies des animaux aquatiques.

Cada vez está más clara la función de los animales acuáticos en relación con la seguridad alimentaria y nutricional del mundo. La demanda planetaria de alimentos derivados de animales acuáticos va en aumento, lo que obliga a incrementar sustancialmente el suministro. El objetivo de asegurar el abastecimiento de animales acuáticos en el futuro gracias a una producción sostenible plantea no pocas dificultades, en la medida en que recursos importantes, como el agua dulce o las tierras, empiezan a escasear en todo el mundo. La acuicultura y la pesca de captura afrontan una serie de amenazas derivadas de los cambios ambientales, ya sean de origen natural o antrópico, en particular el cambio climático. Las praxis y los sistemas acuícolas son vulnerables a esos cambios. Están además las enfermedades de los animales acuáticos, consideradas actualmente uno de los principales frenos a la producción sostenible del sector en el mundo. La necesidad de elevar la producción mundial, combinada con el cambio climático, puede acrecentar el volumen de pérdidas debidas a enfermedades. Los autores examinan las principales fragilidades del sistema, sus consecuencias y la forma de gestionarlas para lograr una producción acuícola mundial más cuantiosa y sostenible, centrándose en la necesidad de aplicar normas internacionales y de desarrollar tanto la seguridad biológica como la capacidad en materia de sanidad de los animales acuáticos para mejorar el estado de salud de estos animales a escala mundial. También se refieren a las investigaciones necesarias para fundamentar sistemas más eficaces de detección y control de las enfermedades de los animales acuáticos.

Epizootics of Streptococcus agalactiae infection in captive rays from Queensland, Australia.

The aim of this study was to describe two epizootics of high mortalities from infection with Streptococcus agalactiae, occurring in captive rays held in a marine display aquarium in south-east Queensland, Australia, in 2009 and 2010. Five different species of rays were affected, including mangrove whiprays (Himantura granulata), estuary rays (Dasyatis fluviorum), eastern shovelnose rays (Aptychotrema rostrata), white-spotted eagle rays (Aetobatus narinari) and blue-spotted mask rays (Neotrygon kuhlii). This report describes the history of both epizootics including collection, quarantine and husbandry of rays, the disease epizootics, clinico-pathological features of the disease, antimicrobial therapy, autogenous vaccine production, and laboratory studies including clinical and histopathology, bacteriology, PCR, molecular serotyping and sequencing of the bacterium S. agalactiae.

Infection and pathology in Queensland grouper, Epinephelus lanceolatus, (Bloch), caused by exposure to Streptococcus agalactiae via different routes.

Since 2007, 96 wild Queensland groupers, Epinephelus lanceolatus, (Bloch), have been found dead in NE Australia. In some cases, Streptococcus agalactiae (Group B Streptococcus, GBS) was isolated. At present, a GBS isolate from a wild grouper case was employed in experimental challenge trials in hatchery-reared Queensland grouper by different routes of exposure. Injection resulted in rapid development of clinical signs including bilateral exophthalmia, hyperaemic skin or fins and abnormal swimming. Death occurred in, and GBS was re-isolated from, 98% fish injected and was detected by PCR in brain, head kidney and spleen from all fish, regardless of challenge dose. Challenge by immersion resulted in lower morbidity with a clear dose response. Whilst infection was established via oral challenge by admixture with feed, no mortality occurred. Histology showed pathology consistent with GBS infection in organs examined from all injected fish, from fish challenged with medium and high doses by immersion, and from high-dose oral challenge. These experimental challenges demonstrated that GBS isolated from wild Queensland grouper reproduced disease in experimentally challenged fish and resulted in pathology that was consistent with that seen in wild Queensland grouper infected with S. agalactiae.