We review studies claiming that fish feel pain and find deficiencies in the methods used for pain identification, particularly for distinguishing unconscious detection of injurious stimuli (nociception) from conscious pain. Results were also frequently misinterpreted and not replicable, so claims that fish feel pain remain unsubstantiated. Comparable problems exist in studies of invertebrates. In contrast, an extensive literature involving surgeries with fishes shows normal feeding and activity immediately or soon after surgery. C fiber nociceptors, the most prevalent type in mammals and responsible for excruciating pain in humans, are rare in teleosts and absent in elasmobranchs studied to date. A‐delta nociceptors, not yet found in elasmobranchs, but relatively common in teleosts, likely serve rapid, less noxious injury signaling, triggering escape and avoidance responses. Clearly, fishes have survived well without the full range of nociception typical of humans or other mammals, a circumstance according well with the absence of the specialized cortical regions necessary for pain in humans. We evaluate recent claims for consciousness in fishes, but find these claims lack adequate supporting evidence, neurological feasibility, or the likelihood that consciousness would be adaptive. Even if fishes were conscious, it is unwarranted to assume that they possess a human‐like capacity for pain. Overall, the behavioral and neurobiological evidence reviewed shows fish responses to nociceptive stimuli are limited and fishes are unlikely to experience pain.

We review the status of marine shellfish ecosystems formed primarily by bivalves in Australia, including: identifying ecosystem-forming species, assessing their historical and current extent, causes for decline and past and present management. Fourteen species of bivalves were identified as developing complex, three-dimensional reef or bed ecosystems in intertidal and subtidal areas across tropical, subtropical and temperate Australia. A dramatic decline in the extent and condition of Australia’s two most common shellfish ecosystems, developed by Saccostrea glomerata and Ostrea angasi oysters, occurred during the mid-1800s to early 1900s in concurrence with extensive harvesting for food and lime production, ecosystem modification, disease outbreaks and a decline in water quality. Out of 118 historical locations containing O. angasi-developed ecosystems, only one location still contains the ecosystem whilst only six locations are known to still contain S. glomerata-developed ecosystems out of 60 historical locations. Ecosystems developed by the introduced oyster Crasostrea gigas are likely to be increasing in extent, whilst data on the remaining 11 ecosystem-forming species are limited, preventing a detailed assessment of their current ecosystem-forming status. Our analysis identifies that current knowledge on extent, physical characteristics, biodiversity and ecosystem services of Australian shellfish ecosystems is extremely limited. Despite the limited information on shellfish ecosystems, a number of restoration projects have recently been initiated across Australia and we propose a number of existing government policies and conservation mechanisms, if enacted, would readily serve to support the future conservation and recovery of Australia’s shellfish ecosystems.

The development of molecular diagnostic assays with increased sensitivity compared with conventional histological techniques is highly desirable for effective management of bonamiosis in cultured oyster stocks and wild populations. A real-time TaqMan PCR assay was developed for the specific detection of Bonamia species in infected oyster tissues. The TaqMan assay was shown to be significantly more sensitive than histopathology. Although a real-time TaqMan PCR assay is comparable with conventional PCR in terms of sensitivity, it offers the advantages that it is a rapid test and has a very low risk of sample cross-contamination. Furthermore, it can be optimised to quantify the parasite load in samples. The assay detected Bonamia isolates from Australia, New Zealand, Europe, Canada, Chile and the USA and therefore demonstrated genus specificity as tested in this study. KEY WORDS: Bonamia spp. · Real-time TaqMan PCR assay · Oyster Resale or republication not permitted without written consent of the publisherDis Aquat Org 71: [75][76][77][78][79][80] 2006 known to harbour Bonamia sp., an endemic isolate that has caused mortalities in the states of Victoria, Tasmania and Western Australia (Hine 1996, CochennecLaureau et al. 2003, Diggles 2003. Other isolates of Bonamia have been reported from O. chilensis in Chile (Campalans et al. 2000), Crassostrea ariakensis in North Carolina (Burreson et al. 2004) and O. puelchana in Argentina (Kroeck & Montes 2005). Taxonomic relationships between these isolates and described species within the genus need to be established.Although recent developments of PCR-based assays have partially addressed the limitations of histology (Carnegie & Cochennec-Laureau 2004), real-time PCR (polymerase chain reaction) has the potential to provide rapid and quantitative results. In order to establish an effective diagnostic capability that will help prevent the introduction of exotic Bonamia spp. and to avoid the spread of enzootic isolates, the development of a molecular-based diagnostic assay that allows rapid, reliable and sensitive detection of Bonamia spp. is required. This report describes the development of a real-time PCR assay capable of detecting Bonamia isolates with greater sensitivity than currently available methods. MATERIALS AND METHODSIsolates of Bonamia spp. Wild flat oysters Ostrea angasi, used as a source of Bonamia sp.-infected tissue, were collected and fixed in 95% ethanol, during the course of a survey on the health and genetics of stocks in 5 estuaries on the south coast of New South Wales, Australia (Heasman et al. 2004). European flat oyster O. edulis tissues, infected with isolates of B. ostreae and fixed in 95% ethanol, were obtained from France (6 samples) and the Netherlands (2 samples). Four bluff oyster O. chilensis tissues, infected with B. exitiosa and fixed in 95% ethanol, were obtained from New Zealand. In addition, DNA prepared from Bonamia-infected oysters O. edulis (Canada and USA) and O. chilensis (Chile) was included in the study. Furthermore,...

Studies were conducted to determine the cause of outbreaks of luminous vibriosis in phyllosoma larvae of the packhorse rock lobster Jasus verreauxi reared in an experimental culture facility. On 2 separate occasions mortalities of up to 75% over a period of 4 wk were observed in 4th to 5th and 8th to 10th instar phyllosomas at water temperatures of 20 and 23°C, respectively. Affected larvae became opaque, exhibited small red spots throughout the body and pereiopods, and were faintly luminous when viewed in the dark. Histopathology showed that the gut and hepatopancreas tubules of moribund phyllosomas contained massive bacterial plaques. The hepatopancreas tubules of moribund larvae were atrophic and some contained necrotic cells sloughed into the lumen. Dense, pure cultures of a bacterium identified as Vibrio harveyi were isolated from moribund larvae. The disease syndrome was reproduced by in vivo challenge and V. harveyi was successfully reisolated from diseased larvae after apparently healthy larvae were exposed by immersion to baths of more than 10 4 V. harveyi ml -1 at 24°C. Injured larvae were more susceptible to infection than were healthy larvae. Survival of larvae experimentally and naturally exposed to V. harveyi was improved when antibiotics were administered via bath exposures.

Intraspecific variation in the ciliate Cryptocaryon irritans was examined using sequences of the first internal transcribed spacer region (ITS-1) of ribosomal DNA (rDNA) combined with developmental and morphological characters. Amplified rDNA sequences consisting of 151 bases of the flanking 18 S and 5.8 S regions, and the entire ITS-1 region (169 or 170 bases), were determined and compared for 16 isolates of C. irritans from Australia, Israel and the USA. There was one variable base between isolates in the 18 S region and 11 variable bases in the ITS-1 region. Despite their similar morphology, significant sequence variation (4.1% divergence) and developmental differences indicate that Australian C. irritans isolates from estuarine (Moreton Bay) and coral reef (Heron Island) environments are distinct. The Heron Island isolate was genetically closer to morphologically dissimilar isolates from Israel (1.8% divergence) and the USA (2.3% divergence) than it was to the Moreton Bay isolates. Three isolates maintained in our laboratory since February 1994 differed in sequence from earlier laboratory isolates (2.9% to 3.5% divergence), even though all were similar morphologically and originated from the same source. During this time the sequence of the isolates from wild fish in Moreton Bay remained unchanged. These genetic differences indicate the existence of a founder effect in laboratory populations of C. irritans. The genetic variation found here, combined with known morphological and developmental differences, is used to characterise four strains of C. irritans.