TAGGING IN GULF OF CARPENTARIA GILBERT RIVER TO FLINDERS RIVER

Transcription

1 TAGGING IN GULF OF CARPENTARIA GILBERT RIVER TO FLINDERS RIVER

2 TAGGING IN GULF OF CARPENTARIA GILBERT RIVER TO FLINDERS RIVER REPORT This report has been prepared by Infofish Australia for the Australian National Sportfishing Association Qld Inc July 2014 SCOPE This report examines tagging data from the Gilbert River to the Flinders River in the Gulf of Carpentaria from :! Tagging and recaptures of key species! Movement of fish tagged DATA SOURCE Tagging and recapture records from maintained in the Suntag database at fish.net. Access to the database is limited to authorised users. Google Earth maps showing tag details are available at fish.net/suntag. BACKGROUND The Australian Government has undertaken a series of studies into the agricultural resources of the Flinders River and Gilbert River catchments (FGARA) as part of the North Queensland Irrigated Agriculture Strategy. This includes an assessment of potential dam sites for capturing water for irrigation and a range of levels of possible water extractions from those rivers. Agricultural development will have some level of impact on the rivers ecology and fish resources. CSIRO have undertaken an assessment of water needs of fisheries resources and ecological values in the Gulf of Carpentaria. Tagging data for that area of the Gulf was included in that assessment. This report summarises the tagging data available for that part of the Gulf. AREA OF TAGGING Locations where fish were tagged are shown using grids on Suntag grid maps as shown in figure 1:! Staaten River (SRG)! Spring Creek (SCG)! Smithburne River (SMG)! Ftizmaurice Creek (FZG)! Norman River (NRG)! Flinders River Bynoe River (FBG) 2

3 Figure 1: Suntag grid map covering Gulf rivers from Gilbert River to Flinders River SOME OBSERVATIONS Based on the data collected on tagging in the Gulf rivers from the following observations are made:! From there were 8,487 fish tagged in the Gulf Rivers with most fish 6,728 (79.3%) tagged in the Norman River.! Barramundi was the most tagged species with 3,411 (40.2%) and Barred Javelin with 3,188 (37.6%).! There were 434 recaptures (5.1%) and this compares with the overall Suntag recapture rate of 6.5%.! There were 240 (7.0%) Barramundi recaptured and 111 (3.3%) Barred Javelin however Pikey Bream had the highest rate of 20.3%.! Of the Barramundi recaptured 9.2% were recaptured outside the system in which they were tagged. The longest distance moved was 390km for a fish tagged in the Norman River and caught in the Nicholson River 1.4 years later.! Juvenile fish below legal size of 580mm moved up to 350km upstream during the wet season flows.! Adult fish above legal size tagged in the freshwater lagoons of the gulf rivers moved downstream up to 420km to the estuaries during wet season flows. 3

4 ! Some Barramundi movements between river system could have been across the floodplain rather than by following the river channels and foreshore.! There were 4 Barramundi tagged below Glenore Weir on the Norman River that were recaptured above the weir indicating that they were able to bypass the weir when it drowned out during the wet season.! King Threadfin tagged in the Gulf rivers and recaptured were all recaptured in the same system as tagged.! King Threadfin tagged in the Weipa area were recaptured south along the gulf coast with one recaptured at the Staaten River (440km south) and another at the Flinders River (600km south).! Most Barred Javelin recaptured were caught within 1 year and within 15km of where tagged with some movement between the Bynoe and Norman Rivers.! Most Pikey Bream were recaptured within 2 months and in the same area as tagged. They are strongly associated with the river system they are in with fish moving to the mouth of the system or just offshore for spawning eg Norman River. FISH TAGGED AND RECAPTURED From (June) there were 8,487 fish tagged with 434 (5.1%) recaptures (recaptured once). Figure 2 shows the number of fish tagged by map area. Most fish were tagged in map area NRG (Norman River) with 6,728 (79.3%). Figure 3 shows where the fish were tagged with the most fish tagged in the Norman River. Figure 2: Number of fish tagged in each Suntag map area

5 Figure 3: Locations where all fish tagged in Gulf rivers SPECIES TAGGED AND RECAPTURED Figure 4: Species tagged and recapture rates Figure 4 shows the number of each species tagged from and the recapture rates. Barramundi were the most tagged species (figure 5) with 3,411 (40.2%) with Barred Javelin 5

6 (figure 6) at 3,188 (37.6%). These 2 species accounted for 77.8% of the fish tagged. There were 240 (7.0%) Barramundi recaptured and 111 (3.3%) Barred Javelin however Pikey Bream had the highest recapture rate at 20.3%. Figure 5: Locations where Barramundi tagged in Gulf rivers Figure 6: Locations where Barred Javelin tagged in Gulf rivers

7 FISH MOVEMENT Fish movement was assessed for Barramundi, Barred Javelin, King Threadfin and Pikey Bream where the location of the fish when tagged and recaptured was sufficiently identified. The distance moved was calculated as the shortest distance by water between the tag and recapture location. BARRAMUNDI MOVEMENT Of the 237 Barramundi recaptured there were 184 where the distance moved could be calculated. Figure 7 shows the movement of Barramundi compared with time at liberty. A total of 17 (9.2%) recaptures were for fish that were recaptured outside the system in which they were tagged. The longest distance moved was 390km for a fish tagged in the Norman River (below Glenore Weir) and caught well up into the freshwater reaches of the Nicholson River 1.4 years later. Figure 7: Distance moved by Barramundi tagged in the Gulf rivers area Another 3 fish moved 350km. A fish tagged in the Norman River (below Glenore Weir) was recaptured well up the Cloncurry River 1.1 years later. The other 2 fish were tagged in the Bynoe River and recaptured 350km up river in the Flinders River after 5 months and 2.3 years. All these fish were from mm when tagged indicating the upstream movement of juvenile fish. Movements were likely to be associated with wet season flows with some movements likely to be over the floodplain rather than through the river channels and foreshore. The longest time at liberty was for a fish that was out for 2,192 days or 6 years. This fish was tagged and recaptured in the Staaten River having moved around 24km. 7

8 There were also 4 fish that were tagged outside the map area that were recaptured within the map area. A fish stocked into Chinaman Reservoir at Cloncurry was recaptured 420km down river in the Bynoe River after 5 months. Another fish tagged in the Cloncurry River was recaptured 360km down river in the Flinders River after 7 months. A fish tagged in the Mitchell River moved 290km south in the gulf and was recaptured 5.7 years later in the Norman River. A fish tagged in the Flinders River was recaptured 265km down river after 6 months. All fish were over legal size when tagged indicating that larger fish move downstream. Figure 8 shows where fish were tagged and recaptured. Figure 8: Movement of Barramundi tagged (shown in red boxes) in the Gulf rivers area There were 4 fish tagged in the Norman River below Glenore Weir that were recaptured above the weir. This indicates that Barramundi can bypass the weir and move upriver during flooding. KING THREADFIN MOVEMENT There were 23 King Threadfin recaptures and of those 20 had sufficient data to calculate movement. Figure 9 shows the distance moved compared with the time at liberty. Of those recaptures 18 (90%) were recaptured in the same system as where tagged. There were 2 fish recaptured outside the system in which they were tagged. One fish tagged in the Hey River at Weipa was recaptured 600km south along the coast in the Flinders River 6 months later and another fish tagged in the Embley River at Weipa was recaptured 440km south along the coast in the Staaten River 8 months later. Figure 10 shows the movement of King Threadfin recaptured in the Gulf rivers area. 8

9 Figure 9: Distance moved by King Threadfin recaptured in the Gulf rivers area Figure 10: Movement of King Threadfin recaptured in Gulf rivers area 9

10 BARRED JAVELIN MOVEMENT Of the 111 recaptures of Barred Javelin there were 110 where the distance moved could be calculated. Of those all except 2 fish were recaptured within a year and all expect 3 fish were recaptured within 10km of where tagged. The further distance moved was 14km. There was 1 fish that moved from the Norman River to the Bynoe River and 1 that moved the other way. One fish out for 4.5 years was recaptured in the same area as tagged. Figure 11 shows the distance moved compared with the time at liberty. Figure 11: Distance moved by Barred Javelin tagged in the Gulf rivers area PIKEY BREAM MOVEMENT Of the 35 recaptures of Pikey Bream the distance moved could be calculated for all fish. Of those all except 2 fish were recaptured within 2 months and all fish were recaptured in the same area as tagged. One fish was recaptured after a year and another after 1.8 years. Both fish were recaptured about 11km from where tagged. Figure 12 shows the distance moved compared with the time at liberty. Pikey Bream are likely to be strongly associated with the river system they are in with fish moving to the mouth of the system or just offshore for spawning eg Norman River. This is supported by tagging data from other systems. 10

11 Figure 12: Distance moved by Pikey Bream tagged in the Gulf rivers area 11