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Black spot disease (diplopstomiasis), an external melanized host inflammatory response caused by a number of digenetic trematode parasites, results in slow growth, deformities and increased mortality among many freshwater fish species globally. We investigated the severity of infection, and genetic parameters for black spot disease among 150 families of Nile tilapia (Oreochromis niloticus) of the Abbassa strain in ponds in Egypt. The causative agent for the black spot disease was identified molecularly as a Uvulifer species using 28S gene. Although 27% of the families remained completely unaffected, the others exhibited signs of black spot infestations randomly distributed in the skin and fins at different levels of severity. Histological examination revealed multiple parasitic cysts surrounded by fibrous capsules with melanin deposits embedded in the muscles. Females were significantly more susceptible than males (P

This paper examines the potential for improved environmental performance of smallholder aquaculture production through ‘beyond-farm’ governance. Smallholder aquaculture farmers face a range of systemic environmental risks related to disease and water quality that extend beyond the boundary of their farms. Yet most governance arrangements aimed at mitigating risks, such as certification, finance and insurance, are focused on the farm-level rather than the wider landscape within which farming takes place. In this paper we propose an integrated approach to area-based management of aquaculture risks that integrates collective action, risk assurance and transfer, and inclusive value chains. In doing so, we set a new research agenda for the integrated governance of mitigating production risks and producer vulnerability in global food production.

Global seafood provides almost 20% of all animal protein in diets, and aquaculture is, despite weakening trends, the fastest growing food sector worldwide. Recent increases in production have largely been achieved through intensification of existing farming systems, resulting in higher risks of disease outbreaks. This has led to increased use of antimicrobials (AMs) and consequent antimicrobial resistance (AMR) in many farming sectors, which may compromise the treatment of bacterial infections in the aquaculture species itself and increase the risks of AMR in humans through zoonotic diseases or through the transfer of AMR genes to human bacteria. Multiple stakeholders have, as a result, criticized the aquaculture industry, resulting in consequent regulations in some countries. AM use in aquaculture differs from that in livestock farming due to aquaculture’s greater diversity of species and farming systems, alternative means of AM application, and less consolidated farming practices in many regions. This, together with less research on AM use in aquaculture in general, suggests that large data gaps persist with regards to its overall use, breakdowns by species and system, and how AMs become distributed in, and impact on, the overall social-ecological systems in which they are embedded. This paper identifies the main factors (and challenges) behind application rates, which enables discussion of mitigation pathways. From a set of identified key mechanisms for AM usage, six proximate factors are identified: vulnerability to bacterial disease, AM access, disease diagnostic capacity, AMR, target markets and food safety regulations, and certification. Building upon these can enable local governments to reduce AM use through farmer training, spatial planning, assistance with disease identification, and stricter regulations. National governments and international organizations could, in turn, assist with disease-free juveniles and vaccines, enforce rigid monitoring of the quantity and quality of AMs used by farmers and the AM residues in the farmed species and in the environment, and promote measures to reduce potential human health risks associated with AMR. Electronic supplementary material The online version of this article (10.1007/s11625-017-0511-8) contains supplementary material, which is available to authorized users.