Gladstone Fish Health Investigation 2011 - 2012 - Western Basin ...
Gladstone Fish Health Investigation 2011 - 2012 - Western Basin ... Gladstone Fish Health Investigation 2011 - 2012 - Western Basin ...
Table 3. Numbers of samples tested by Biosecurity Queensland during Phase 1.Fish Species Necropsy Histopathology Microbiology ResidueHeldfrozenBarramundi (Lates calcarifer) 33 69 30 6 27Black jew (Protonibea diacanthus) 0 1 1 0 0Bony bream (Nematalosa erebi) 1 1 0 0 1Catfish (Ariidae) 9 6 6 6 0Flathead (Platycephalus sp.) 0 0 0 0 2Grinner (Bathysauridae,Synodontidae)1 1 0 0 1Mullet (Mugilidae) 2 2 3 4 2Queenfish (Scomberoides spp.) 2 2 2 0 2River jew (Johnius spp.) 7 7 3 7 0Scats (Scatophagidae) 2 2 0 0 1Spangled emperor (Lethrinusnebulosus)1 1 1 0 1Cod/Groupers (Epinephelus sp.) 1 1 1 0 0Threadfin (Polynemidae) 2 2 0 0 2Trevally (Carangidae) 2 2 0 0 1Whiting (Sillago spp) 1 6 1 4 1Sharks (multiple families) 5 21 21 0 2Total 69 124 69 27 43Crustaceans and molluscs Necropsy Histopathology Microbiology ResidueHeldfrozenCrabs (Portunidae) 9 8 8 0 2Moreton Bay bug (Thenus sp.) 1 0 0 0 3Prawns (Penaeidae) 2 11 2 7 1Scallops (Pectinidae) 0 7 0 63 0Total 12 26 10 70 6Table 4. Numbers of samples used for necropsy examination during Phase 2.BullOtherLocation BarramundiMullet QueenfishMud crab TotalsharkpelagicBundaberg 17 1 20 20 21 79Fitzroy River 20 7 21 11 2 21 82Calliope River 20 3 17 18 58Hamilton Point 20 1 20 41Lower Boyne 20 20 1 41Rodds Bay 9 20 20 49Spoil Ground 5 15 20Upper Boyne 16 20 36Narrows 20 20Port Dev’t Area 21 21Lake Awoonga 5 5Total 127 12 118 37 17 141 45223
Significant findings and discussionAnalysis of all species combinedThe structured sampling in Phase 2 allowed a statistical analysis to be done on fieldobservations and necropsy data from all species combined (Appendix B). Overall, locationhad a significant effect on most variables, and for many variables there was a significantinteraction (P < 0.05) between location and trip, indicating a changing pattern through spaceand time.Health assessment index (HAI) was calculated based on the methods of Adams et al. (1993),as a coarse measure of overall health, based on combined scores from a range of internaland external observations made during necropsy. Higher scores indicated a higherprevalence and/or severity of abnormalities. In Trip 1, average HAI was highest in Bundaberg(32.8), followed by the Lower (32.7) and Upper Boyne (30.9) respectively. In Trip 2, theUpper Boyne had by far the highest HAI score (38.8) followed by Lower Boyne (28.2) andBundaberg (24.6). There was no significant difference between pooled Gladstone sites 2 andpooled reference sites for HAI in either Trip 1 or 2.In Trip 1, external observations and measurements showed that Gladstone fish hadsignificantly lower condition factor (weight×10 5 /Length 3 ) and higher proportion of tuckedabdomen (poor condition) than fish from the reference sites (P ≤ 0.05). Internal observationssupport this finding with a significantly lower proportion of mesentery fat in fish fromGladstone. In particular, fish from Hamilton Point had the lowest condition factor and lowestlevels of mesentery fat in both trips, while Bundaberg fish had the highest condition factors inboth trips.The estimated annual growth rate (2011) of barramundi in Gladstone (Boyne River44.0±50.5mm and Calliope River 49.1±40.0m) compared with the Fitzroy River(169.8±67.6mm) (Sawynok, et al 2013) for barramundi greater than 650 mm could indicatelimited food supply that results in poor condition as found in Trip 1.In Trip 2, the proportion of fish with parasites identified during necropsy was significantlygreater in fish from Gladstone (P < 0.05), with the highest level observed in barramundi fromHamilton Point.Prevalence of lesions and fin abnormalities was significantly higher in Gladstone than in thereference sites for both trips (P < 0.05). The lesions in particular can be largely explained bythe high numbers of barramundi with lesions observed from the Boyne River during both tripsduring Phase 2.Externally visible health ‘status’ was assessed in the field for every individual fish. Necropsydata were tested for differences between apparently normal and abnormal fish. Liverabnormalities were significantly higher in apparently abnormal fish (P < 0.05). However,despite significant differences in lesions and fin abnormalities between Gladstone andreference sites, the only significant difference in livers between Gladstone and referencesites was in Trip 2 when liver colour abnormalities in fish from Gladstone were significantlyless prevalent than at the reference sites.2 Gladstone sites refers to Gladstone Harbour and adjacent waterways including the Boyne andCalliope Rivers and the Narrows.24
- 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 and 12: Phase 1 (August 2011-February 2012)
- Page 13 and 14: The results in this study support t
- 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: Table 2. The number of fish, crusta
- 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 and 78: FinfishObservational findingsDuring
Significant findings and discussionAnalysis of all species combinedThe structured sampling in Phase 2 allowed a statistical analysis to be done on fieldobservations and necropsy data from all species combined (Appendix B). Overall, locationhad a significant effect on most variables, and for many variables there was a significantinteraction (P < 0.05) between location and trip, indicating a changing pattern through spaceand time.<strong>Health</strong> assessment index (HAI) was calculated based on the methods of Adams et al. (1993),as a coarse measure of overall health, based on combined scores from a range of internaland external observations made during necropsy. Higher scores indicated a higherprevalence and/or severity of abnormalities. In Trip 1, average HAI was highest in Bundaberg(32.8), followed by the Lower (32.7) and Upper Boyne (30.9) respectively. In Trip 2, theUpper Boyne had by far the highest HAI score (38.8) followed by Lower Boyne (28.2) andBundaberg (24.6). There was no significant difference between pooled <strong>Gladstone</strong> sites 2 andpooled reference sites for HAI in either Trip 1 or 2.In Trip 1, external observations and measurements showed that <strong>Gladstone</strong> fish hadsignificantly lower condition factor (weight×10 5 /Length 3 ) and higher proportion of tuckedabdomen (poor condition) than fish from the reference sites (P ≤ 0.05). Internal observationssupport this finding with a significantly lower proportion of mesentery fat in fish from<strong>Gladstone</strong>. In particular, fish from Hamilton Point had the lowest condition factor and lowestlevels of mesentery fat in both trips, while Bundaberg fish had the highest condition factors inboth trips.The estimated annual growth rate (<strong>2011</strong>) of barramundi in <strong>Gladstone</strong> (Boyne River44.0±50.5mm and Calliope River 49.1±40.0m) compared with the Fitzroy River(169.8±67.6mm) (Sawynok, et al 2013) for barramundi greater than 650 mm could indicatelimited food supply that results in poor condition as found in Trip 1.In Trip 2, the proportion of fish with parasites identified during necropsy was significantlygreater in fish from <strong>Gladstone</strong> (P < 0.05), with the highest level observed in barramundi fromHamilton Point.Prevalence of lesions and fin abnormalities was significantly higher in <strong>Gladstone</strong> than in thereference sites for both trips (P < 0.05). The lesions in particular can be largely explained bythe high numbers of barramundi with lesions observed from the Boyne River during both tripsduring Phase 2.Externally visible health ‘status’ was assessed in the field for every individual fish. Necropsydata were tested for differences between apparently normal and abnormal fish. Liverabnormalities were significantly higher in apparently abnormal fish (P < 0.05). However,despite significant differences in lesions and fin abnormalities between <strong>Gladstone</strong> andreference sites, the only significant difference in livers between <strong>Gladstone</strong> and referencesites was in Trip 2 when liver colour abnormalities in fish from <strong>Gladstone</strong> were significantlyless prevalent than at the reference sites.2 <strong>Gladstone</strong> sites refers to <strong>Gladstone</strong> Harbour and adjacent waterways including the Boyne andCalliope Rivers and the Narrows.24
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