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

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Areas of detached scales associated with parasitic infection were observed on a number ofshark species caught during the sampling program from Gladstone Harbour and thereference sites. It is unknown whether the numbers of parasites observed on sharks duringthis program are abnormal, however it is evident that these parasites and associatedpathology are not unique to Gladstone. Severe skin redness was observed during necropsy,however this was not apparent in freshly caught sharks; redness developed in the hours afterdeath. This post-mortem redness was not unique to Gladstone.Large numbers of prawns and fish were caught on trawlers both in Gladstone Harbour andthe reference sites, with no significant redness or other abnormalities observed.No significant abnormalities were identified from the sampling and necropsy examination ofpelagic species.Histopathology investigation indicated that gill, liver and skin tissue of grinner, and the gill,hepatopancreas and muscle tissue of mud crabs was similar in Gladstone samples toreference sites. Some bleeding and swelling was observed in shark skin from both Gladstoneand reference sites.Chemical residue testing of crabs from both Gladstone and reference sites found asignificant association between aluminium and selenium concentrations, and shell lesions.Given that concentrations of metals in mud crab hepatopancreas were similar to historicaldata from sites across the east coast of Queensland, any effect of these metals on shelllesions is unlikely to be unique to Gladstone. The available data also indicated that the suiteof organic chemicals tested did not contribute to crab disease.Chemical residue testing of muscle tissue from grinner showed no significant differencebetween Gladstone and reference sites.ConclusionsIt is obvious from all the reports that something happened to aquatic life in GladstoneHarbour in 2011. The findings provided in this study indicate that the fish health in GladstoneHarbour had returned to a more normal situation in 2012. Other than the physical damage orrecovery from physical damage, this study found the sampled fish in a health status similar tothat observed in the Bundaberg and Fitzroy reference sites.All industrial activities in Gladstone that were operating in Gladstone in 2011 have continuedto operate, including dredging. The only factor different in 2011 compared to previous yearswas the significant rainfall, the subsequent flooding and the introduction of a significantbiomass of fish from Lake Awoonga. Flooding has also occurred in 2012 and 2013.However, other than continuing reports of barramundi showing physical damage as the resultof being washed over the Awoonga spillway in these flooding events, reports of anyreoccurence of sick fish have not been received by DAFF.The most likely cause of the abnormalities observed during this investigation is the suddenintroduction of barramundi and other fish from Lake Awoonga during December 2010 to early2011. Although barramundi are naturally able to move between fresh and salt waterenvironments, it appears that these fish were overcrowded and unable to feed normally afterthey were suddenly re-located from Lake Awoonga into the Boyne River. The stresspreceded parasitic infestation during the colder winter water temperatures in 2011. TheNeobenedenia infestation subsided as the water temperature increased and fish densityreduced, as shown by improving fish health in late 2011 and 2012.7
The results in this study support that it was flooding combined with the introduction of asignificant biomass of fish (including barramundi, mullet, catfish and bony bream) thatstressed the ecosystem in Gladstone Harbour and adjacent waterways. This study cannotrule out the possibility that the activity of dredging and associated turbidity providedadditional stress to the ecosystem, but it was not the primary stressor.8
Page 1 and 2: Department of Agriculture, Fisherie
Page 3 and 4: ContentsTable of tables 1Table of f
Page 5 and 6: Mullet (Mugilidae) 80Banana prawn (
Page 7 and 8: Figure 7. Barramundi caught in the
Page 9 and 10: Figure 38. Sharks caught in the Cal
Page 11: Phase 1 (August 2011-February 2012)
Page 15 and 16: ecognised expertise and research pu
Page 17 and 18: Mr Mitchell reported high catches u
Page 19 and 20: Figure 2. Sampling sites within the
Page 21 and 22: Phase 2: Expanded Gladstone Fish He
Page 23 and 24: Mud crab (Scylla serrata): Mud crab
Page 25 and 26: 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
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Encysted larval parasites were foun
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in particular bull sharks, have bee
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Commercial banana prawn catch for t
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Observational findings Phase 2April
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Laboratory testing Phase 1Seven riv
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four displayed signs of redness. Th
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Conditions observed in pelagic fish
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FinfishObservational findingsDuring
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ConclusionsIn 2011, a wide range of
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Mud crabsFisheries Queensland did n
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Owens, L. 1983. Bopyrid isopod Epip
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Candidate speciesThe monitoring pro
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Table 1: Candidate species for each
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Sample processingSample processing
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Herring/grinner/Australian threadfi
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For example: the third specimen, re
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oooGonad - present/absentHepatopanc
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Cloudy eye,swollen,redness orhemorr
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Red pin pointmarks - nogeneral redn
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Lesion photos Description GradeThis
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L4continuedoperculumgrazing;cuts or
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Appendix A-3: Fish health assessmen
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Appendix B - Statistical report: Gl
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analyses, but this was not done for
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was a significant (P < 0.05) locati
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Percentage with fin condition > 015
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Table 3.6b. Effects of locations an
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Table 3.7d. Spleen categories - cou
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32Bundy2Bundy1UpBoyne1UpBoyne2LwBoy
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Table 3.9c. Regional group means an
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Table 4.2c. Effects of locations an
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4.5 Summarising by regionsThe means
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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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