Gladstone Fish Health Investigation 2011 - 2012 - Western Basin ...

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No bacterial, parasitic or fungal pathogens were found that could explain the skin conditionson other finfish species.A range of bacteria were isolated from the fish, for example Moraxella spp, Micrococcus spp,Proteus vulgaris, and Pseudomonas spp. The lack of distinct invasion or proliferation on theskin and muscle lesions suggests that these bacteria were opportunistic and secondarycolonisers following the initial skin damage. These bacteria are not considered to be fishpathogens (i.e. they are not primary infectious agents that cause disease in fish). They arenormal microorganisms of the marine environment.73
ConclusionsIn 2011, a wide range of fish species in Gladstone were reported with health issuessupporting the hypothesis that the Gladstone Harbour ecosystem as a whole was understress. Barramundi provided the clearest and most consistent evidence for the cause of illhealth. In the other species, there appeared to be a range of observed symptoms. Anecdotalreports were received of increased levels of rust spot disease in mud crabs, firstcharacterised by Andersen and Norton (2001).An investigation began in September 2011 to determine the cause of the reported issues andspecifically to address public concern regarding the potential impact of industrial activityincluding dredging in Gladstone Harbour. The investigation, conducted by DAFF, was part ofa whole-of-government response.BarramundiIn September 2011, an external parasitic fluke Neobenedenia sp, was identified inbarramundi from the Gladstone Harbour. Neobenedenia was identified as the cause of theobserved eye problems and contributed to a number of the observed skin conditions inbarramundi.This parasite has previously been found in Queensland waters in the Hinchinbrook Channelbetween Hinchinbrook Island and mainland Queensland where barramundi are in highdensities (Deveney, et al, 2001), and had resulted in the loss of approximately 200 000cultured fish.An additional factor was the significant number of barramundi (estimated 30 000) washed outof the Awoonga Dam in the flooding during 2010/11. Many of these fish would have receivedphysical damage as a result of being washed over the spillway. This damage was reportedby recreational fishes as physical damage and was documented in necropsies of barramundiundertaken by a veterinarian with specialist skills in fish and aquatic animals in 2012 after asecond overtopping of Awoonga Dam. The fish showed damage to the jaw and head andusually presented with unilateral injuries to scales that appeared like a grazing along thebody.In the winter of 2011, the population of barramundi in the Boyne River was under extremestress. The densities of these large predatory barramundi in the Boyne River were at higherlevels than the system could naturally sustain, resulting in fish in poor condition and lowergrowth rates (Sawynok, et al, 2013). Their immune systems were further stressed by lowwinter water temperatures, resulting in an environment where the natural population of theparasite Neobenedenia could rapidly proliferate, and in turn resulting in observed eyeproblems and increases in fish exhibiting skin conditions (e.g. redness, loss of individualscales).As the water temperature increased, and the densities of barramundi were reduced byfishing (130 t of barra were caught by commercial fishers in the third quarter of 2011), theremaining barramundi became healthier. In 2012 and in 2013, other than barramundishowing relatively minor physical damage, no significant health issues have been reportedfor barramundi caught in the Gladstone region.These results are consistent with flooding and the significant number of barramundi beingwashed into the Boyne River. If the cause of the fish ill health continued beyond 2011, thehealth of the fish would not be improving and Neobenedenia infections would have beenseen in September 2012.74
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Department of Agriculture, Fisherie
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ContentsTable of tables 1Table of f
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Mullet (Mugilidae) 80Banana prawn (
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Figure 7. Barramundi caught in the
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Figure 38. Sharks caught in the Cal
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Phase 1 (August 2011-February 2012)
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The results in this study support t
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ecognised expertise and research pu
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Mr Mitchell reported high catches u
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Figure 2. Sampling sites within the
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Phase 2: Expanded Gladstone Fish He
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Mud crab (Scylla serrata): Mud crab
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For mud crabs, hepatopancreas, gill
Page 27 and 28: Table 2. The number of fish, crusta
Page 29 and 30: Significant findings and discussion
Page 31 and 32: Commercial barramundi catch and cat
Page 33 and 34: Figure 6. Eye condition observed in
Page 35 and 36: Conditions observed in barramundi s
Page 37 and 38: Figure 12. A barramundi caught in t
Page 39 and 40: provided another environmental stre
Page 41 and 42: was somewhat reduced because post-m
Page 43 and 44: 4,000Commercial effort (days fished
Page 45 and 46: Size structure of mud crabs observe
Page 47 and 48: Figure 21. Examples of shell abnorm
Page 49 and 50: Of the 58 crabs observed to have sh
Page 51 and 52: HistopathologyLipid storage vacuola
Page 53 and 54: Commercial fishing effort for mulle
Page 55 and 56: Figure 28. (a) Mullet caught in Rod
Page 57 and 58: June/July: Mullet samples were coll
Page 59 and 60: Sharks and raysThe monitoring progr
Page 61 and 62: Observational findings Phase 1Phase
Page 63 and 64: Encysted larval parasites were foun
Page 65 and 66: in particular bull sharks, have bee
Page 67 and 68: Commercial banana prawn catch for t
Page 69 and 70: Observational findings Phase 2April
Page 71 and 72: Laboratory testing Phase 1Seven riv
Page 73 and 74: four displayed signs of redness. Th
Page 75 and 76: Conditions observed in pelagic fish
Page 77: FinfishObservational findingsDuring
Page 81 and 82: Mud crabsFisheries Queensland did n
Page 83 and 84: Owens, L. 1983. Bopyrid isopod Epip
Page 85 and 86: Candidate speciesThe monitoring pro
Page 87 and 88: Table 1: Candidate species for each
Page 89 and 90: Sample processingSample processing
Page 91 and 92: Herring/grinner/Australian threadfi
Page 93 and 94: For example: the third specimen, re
Page 95 and 96: oooGonad - present/absentHepatopanc
Page 97 and 98: Cloudy eye,swollen,redness orhemorr
Page 99 and 100: Red pin pointmarks - nogeneral redn
Page 101 and 102: Lesion photos Description GradeThis
Page 103 and 104: L4continuedoperculumgrazing;cuts or
Page 105 and 106: Appendix A-3: Fish health assessmen
Page 107 and 108: Appendix B - Statistical report: Gl
Page 109 and 110: analyses, but this was not done for
Page 111 and 112: was a significant (P < 0.05) locati
Page 113 and 114: Percentage with fin condition > 015
Page 115 and 116: Table 3.6b. Effects of locations an
Page 117 and 118: Table 3.7d. Spleen categories - cou
Page 119 and 120: 32Bundy2Bundy1UpBoyne1UpBoyne2LwBoy
Page 121 and 122: Table 3.9c. Regional group means an
Page 123 and 124: Table 4.2c. Effects of locations an
Page 125 and 126: 4.5 Summarising by regionsThe means
Page 127 and 128: Ta ble 5.2a. Effects of locations a
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5.5 Summarising by regionsThe means
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6.3 ResultsThere was no significant
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Table 6.5 lists the mean values whe
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Standardized residualsStandardized
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Table 2.3f. Muscle lesions.Lake Fit
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Table 4. 1f. Muscle lesions.Fitzroy
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Table 5.6. Regiona l m eans for the
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Contaminants in Tissue ofFish and C
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Contaminants in Tissue of Fish and
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Department of Science, Information
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Appendix E - Time line BarraBy John
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friends. Rapidly rising flood water
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To make note - condition loss was e
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May/June- FinsMy initial observatio
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Thes e escapee were now also in awo
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Figure N. Barramundi showing net ma
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September- Deaths and SicknessFigur
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There is numerous distinguishing fe
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Department of Agriculture, Fisherie
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Gladstone Fish Health Investigation 2011 - 2012 - Western Basin ...

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