| Survey/Project Number: | 1179 Total No. of Sites: 23 |
| Survey/Project Name: | Kangaroo Island Freshwater, Estuarine and Migratory Fish Assessment |
| Abstract: | Objectives - To assess the diadromous fish community across representative freshwater catchments on Kangaroo Island and to identify barriers which may prevent migration of juveniles during spring recruitment periods. Surveys, species and status Kangaroo Island freshwater catchments are documented as supporting low native fish diversity compared to neighbouring freshwater systems across the Fleurieu Peninsula and River Murray. Two recent surveys have been undertaken on Kangaroo Island to assess freshwater and estuarine fish communities. - South Australian Research and Development Institute (SARDI) Aquatic Sciences investigated the environmental water requirements of native fish in the Middle River and adjacent catchments during summer 2009 and winter 2010. - Native Fish Australia conducted baseline monitoring of freshwater catchments across the island in 2005. These and other opportunistic surveys conducted post 1990 have recorded three diadromous and one native freshwater obligate fish species from Kangaroo Island's freshwater catchments. Historical records suggest species diversity was higher in catchments across the island, however some records still remain unverified i.e. river blackfish (Gadopsis marmoratus) from the Middle River in 1987 (Hamer 2009). Modifications made to freshwater systems and the introduction of invasive taxa, such as rainbow trout (Oncorhynchus mykiss) and marron (Cherax tenunanus), have likely seen a reduction in the number of species found on the island today. It is also possible that the number of diadromous fish species thought to currently occur on Kangaroo Island is under represented. The island has received a relatively low level of survey effort and the timing of surveys has not coincided with peak migration periods for juvenile diadromous fish species. The capture in January 2017 of an adult female congolli (Pseudaphritis urvillii) by Natural Resources Kangaroo Island staff in the lower section of the Cygnet River estuary is the first record for the island. This record suggests that this species may utilise freshwater habitats on the island to complete its freshwater obligate life cycle. Diadromous fish species must migrate between freshwater and marine habitats to complete their lifecycle. This obligate life history means they are often resilient to extremes in water quality, however they are extremely susceptible to barriers which impede migration. Marine dispersal of eggs and larvae in catadromous and in adult anadromous species allows most species to be widely distributed. This strategy facilitates recruitment across both localised and broad scales throughout the species distribution and may allow these species to recolonise catchments under favourable environmental conditions. This pilot study will survey representative sites across Kangaroo Island to improve our understanding on the current status of the diadromous and freshwater fish community. It will identify the first instream barriers in these catchments that obstruct the movement of juvenile diadromous fish migrating into rivers from the sea or estuary. Surveys at these sites will sample both downstream and upstream of instream barriers. This will capture a snapshot of the fish community that is attempting to migrate and those that successfully ascend this first instream barrier. In the absence of instream barriers, sampling will take place at the estuarine/freshwater interface to capture transitioning juvenile diadromous fish species. Sampling will take place in late October to capture the beginning of the known migration period for juvenile catadromous species attempting upstream migration and juvenile anadromous species migrating downstream to the sea. |
| Start Date: | 05/01/2017 End Date: 03/11/2017 |
| Survey Type: | Fauna only |
| Study Area Description: | Kangaroo Island |
| Objectives | |||
| Vegetation: | *** No vegetation survey objectives recorded | ||
| Fauna: | Refer to Abstract. | ||
| Methodology | |||
| Vegetation: | *** No vegetation methodology recorded | ||
| Fauna: | Methods Double winged fyke nets should where possible be set across the entire stream width. 2 mm mesh wing fyke nets must be facing downstream, 4 mm mesh wing fyke nets must be facing upstream. Fyke nets will be set in the afternoon and retrieved the following morning. Nets should be soaked for a minimum of 12 hours and no longer than 24 hours. Each fyke net will have a surface float placed inside towards the coded to ensure air breathing bycatch remains in a healthy condition until the net is retrieved. Staking of wings and codend must be secured under tension. Select a site with a flat stream bed as close as possible to the instream barrier and make sure the wings lead line is in contact with the bottom and the float line is at surface water level. Wings should be set at a 45o angle across the flow to lead and entrap all fish attempting to migrate. The base of the fyke entrance hoop needs to be flush with the bottom, to prevent escape of fish under the net. a) To assess the migratory fish community attempting to move upstream a fyke net will be set below the first instream barrier from the sea. A second fyke will be set above the barrier and orientated upstream to sample the downstream movement of migratory fish species. b) To assess the migratory fish community which successfully ascends the first instream barrier from the sea a fyke net will be set directly upstream of the barrier. A second fyke will be set above the first fyke and orientated upstream to sample the downstream movement of migratory fish species. In the absence of instream barriers, sampling will take place at the estuarine/freshwater interface to capture transitioning juvenile diadromous fish species. One fyke will be set orientated downstream the other orientated upstream. If large numbers of fish are sampled, sub-samples can be taken to represent the total catch, using counted dip net scoops which are multiplied up across the number of scoops for the entire catch. If individual species are abundant a maximum sub-sample of 50 individuals should be measured. Photos must be taken from above and below the instream barrier and of each fyke net set at each location. Further data should be collected to describe the instream barrier including stream width, depth, head difference (height difference in water level above and below the barrier), substrate type, if the barrier is natural or artificial and comments about flow characteristics and if any fish are observed at the site. Data sheets will be provided to collect this information. | ||
| Data Distribution Rules: | Public Dataset |
| Project Basis: | Fauna : Baseline Survey of flora and/or fauna - Standard Biol Survey of SA survey methodology not used. |
| Information Authority: | Kangaroo Island Natural Resources Management (NRM) Region |