Approximately 70% of the aquatic-based production of animals is fed aquaculture, whereby animals are provided with high-protein aquafeeds. Currently, aquafeeds are reliant on fish meal and fish oil sourced from wild-captured forage fish. However, increasing use of forage fish is unsustainable and, because an additional 37.4 million tons of aquafeeds will be required by 2025, alternative protein sources are needed. Beyond plantbased ingredients, fishery and aquaculture byproducts and insect meals have the greatest potential to supply the protein required by aquafeeds over the next 10-20 years. Food waste also has potential through the biotransformation and/or bioconversion of raw waste materials, whereas microbial and macroalgal biomass have limitations regarding their scalability and protein content, respectively. In this review, we describe the considerable scope for improved efficiency in fed aquaculture and discuss the development and optimization of alternative protein sources for aquafeeds to ensure a socially and environmentally sustainable future for the aquaculture industry.

Ninety-three giant Queensland grouper, Epinephelus lanceolatus (Bloch), were found dead in Queensland, Australia, from 2007 to 2011. Most dead fish occurred in northern Queensland, with a peak of mortalities in Cairns in June 2008. In 2009, sick wild fish including giant sea catfish, Arius thalassinus (Rüppell), and javelin grunter, Pomadasys kaakan (Cuvier), also occurred in Cairns. In 2009 and 2010, two disease epizootics involving wild stingrays occurred at Sea World marine aquarium. Necropsy, histopathology, bacteriology and PCR determined that the cause of deaths of 12 giant Queensland grouper, three wild fish, six estuary rays, Dasyatis fluviorum (Ogilby), one mangrove whipray, Himantura granulata (Macleay), and one eastern shovelnose ray, Aptychotrema rostrata (Shaw), was Streptococcus agalactiae septicaemia. Biochemical testing of 34 S. agalactiae isolates from giant Queensland grouper, wild fish and stingrays showed all had identical biochemical profiles. The 16S rRNA gene sequences of isolates confirmed all isolates were S. agalactiae; genotyping of selected S. agalactiae isolates showed the isolates from giant Queensland grouper were serotype Ib, whereas isolates from wild fish and stingrays closely resembled serotype II. This is the first report of S. agalactiae from wild giant Queensland grouper and other wild tropical fish and stingray species in Queensland, Australia.

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.

The black tiger shrimp (Penaeus monodon) remains the second most widely cultured shrimp species globally; however, issues with disease and domestication have seen production levels stagnate over the past two decades. To help identify innovative solutions needed to resolve bottlenecks hampering the culture of this species, it is important to generate genetic and genomic resources. Towards this aim, we have produced the most complete publicly available P. monodon transcriptome database to date based on nine adult tissues and eight early life-history stages (BUSCO - Complete: 98.2% [Duplicated: 51.3%], Fragmented: 0.8%, Missing: 1.0%). The assembly resulted in 236,388 contigs, which were then further segregated into 99,203 adult tissue specific and 58,678 early life-history stage specific clusters. While annotation rates were low (approximately 30%), as is typical for a non-model organisms, annotated transcript clusters were successfully mapped to several hundred functional KEGG pathways. Transcripts were clustered into groups within tissues and early life-history stages, providing initial evidence for their roles in specific tissue functions, or developmental transitions. We expect the transcriptome to provide an essential resource to investigate the molecular basis of commercially relevant-significant traits in P. monodon and other shrimp species.

In the summer of 1999/2000, an epizootic occurred in cultured juvenile redclaw crayfish Cherax quadricarinatus on one commercial crayfish farm in northern Queensland, Australia. Mortalities occurred over 4 wk, with up to 96% cumulative mortalities in 2 earthen ponds stocked with juveniles. The crayfish were weak, anorexic and lethargic. A transmission trial was conducted, using filtered, cell-free extract prepared from infected crayfish as inoculum. The disease was reproduced, with on-going mortalities occurring in inoculated crayfish over 55 d. Experimentally inoculated crayfish showed gross signs of malaise, anorexia and disorientation before dying. Two types of intranuclear inclusion bodies (INIBs) were seen in tissues of endodermal, ectodermal and mesodermal origin by light microscopy with haematoxylin and eosin (H&E) stained sections. 'Early'-stage INIBs were eosinophilic, rounded and located centrally within slightly enlarged nuclei while 'late'-stage INIBs were well-rounded and deeply basophilic. The gills, cuticular epithelium and epithelial cells of the foregut, midgut and hindgut were the most heavily infected tissues. By transmission electron microscopy, virions with an average diameter of 19.5 nm were seen within electron-dense granular inclusion bodies within enlarged nuclei of both naturally and experimentally infected crayfish. The size of the virions and cytopathology are consistent with characteristics of viruses in the Family Parvoviridae. This is the first reported case of mass mortality caused by a parvo-like virus infection in C. quadricarinatus. KEY WORDS:Cherax quadricarinatus · Virus · Parvo-like virus · Disease · Aquaculture · Crayfish · Pathology Resale or republication not permitted without written consent of the publisherDis Aquat Org 50: [79][80][81][82][83][84][85][86] 2002 clinical viral infections have been reported (Edgerton et al. 1994, Edgerton & Owens 1999, but crayfish with these infections have usually been coinfected with bacterial and/or other pathogens. Mass mortalities in pond-reared redclaw have so far been caused by bacterial diseases including vibriosis (Eaves & Ketterer 1994) and those due to infections with rickettsiales-like organisms (Ketterer et al. 1992).In December 1999 and January 2000, 1 redclaw crayfish farm in Queensland, Australia, reported higher than average mortalities in 2 earthen ponds stocked with juvenile crayfish Cherax quadricarinatus. Cumulative mortalities of up to 96% occurred over 2 mo. Histopathological examination of diseased crayfish revealed intra-nuclear inclusion bodies that resembled those associated with parvo-like viral infections. In February 2000, on-going mortalities occurred in other ponds on this farm stocked with adult crayfish. There was an estimated 50% loss in total farm production, due to losses of juvenile and adult crayfish and the farm subsequently closed down for a total destocking and pond disinfection. A detailed disease investigation was carried out to determine the cause of the mortalities.The results an...

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These two authors contributed equally to the writing of this publication Affiliations: (which was not peer-reviewed) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity.The copyright holder for this preprint . http://dx.doi.org/10.1101/280420 doi: bioRxiv preprint first posted online Mar. 14, 2018; 2 DeclarationsAvailability of data and material Raw data, assembly and bioinformatics scripts will be made freely available online upon publication. . CC-BY-NC-ND 4.0 International license It is made available under a (which was not peer-reviewed) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity.The copyright holder for this preprint . http://dx.doi.org/10.1101/280420 doi: bioRxiv preprint first posted online Mar. 14, 2018;