Range: The range of the Deep-body pipefish extends from Victoria westward to mid-western South Australia.

Habitat: In South Australia populations of the Deep-body pipefish appear restricted inshore <2m Zostera seagrass beds along tidal channels in or adjacent to mangroves, or in Zostera seagrass flats inshore of Posidonia seagrass beds. At one site numerous Deep-body pipefish were found in Zostera beds inshore of Posidonia beds as the water deepened to lower than 1 meter below low tide mark, but no Deep-body pipefish were in the Posidonia beds. For unknown reasons the Deep-body pipefish and the Wide-body pipefish are rarely found together even though they both inhabit shallow areas of Zostera seagrass.

Deep-body pipefish appears highly tolerant of fluctuations and extremes of temperature and salinity. Recent surveys of this species in mangrove channels in north eastern Gulf St. Vincent , and aquarium studies (Smith 2003), show the species is capable of surviving water temperatures of above 30 Centigrade (Browne and Smith, 2004a), and their habitat probably reaches far higher temperatures and salinity in late summer (February- March).

Fresh water flooding after heavy rains is tolerated by this species with numbers of these pipefish observed in channels with fresh very muddy water. Deep-body pipefish survived for four hours in fresh water before return to salt water. A slight lethargy had developed at this time. However, the pipefish resumed normal behaviour and feeding for 12 hrs after return to seawater.

Deep-body pipefish can be found in banks of Zostera seagrass which are exposed at low tide. The fate and behaviour of the pipefish is unknown during this period when temperatures must become extreme for several hours.

Population Dynamics:

Immature: Samples at three sites from June-December show just hatched Deep-body Pipefish were only found in December. This supports no spawning from June to October, then spawning seasonally from October to at least December. Further studies are need to find the reproductive pattern from December to May. These juveniles had had a minimum (n= 50) length of 26.1mm (hatch length 15mm), a maximum of 74.2mm, an average of 55.3mm, a standard deviation of 11.2mm, a median of 57.5mm, and a mode of 65.2mm.

Males : Deep-body pipefish were examined for length and reproductive status in the north eastern Gulf St. Vincent in 2003. This sample showed a minimum male (n= 69) length was 62.7mm, the maximum 116.5mm, the average 94mm, a standard deviation of 10.5mm, and a mode of 100mm.

Females: Immature females had a minimum (n= 10) length of 73.7mm, a maximum of 92.6mm, an average of 83.5mm, a standard deviation of 6.6mm, and a median of 84.5mm. Mature females with a typical flat shape and bright colour had a minimum (n= 33) length of 67.3mm, a maximum of 119.1mm, an average of 94.1mm, a standard deviation of 11.9mm, a mode of 90.1mm, and a median of 96.2mm.

Reproduction: In South Australia males have been recorded with brood pouches from October, November, December, and brooding eggs in November, December. The number of eggs in SA Museum specimens from 17 males ranged (range 22) from 3 to 25 with an average of 16 and a standard deviation of 6.2, and a median and mode of 18 (Browne et al., 2004). In a sample of 49 males from the northern Gulf St. Vincent during September to December (see population dynamics) 35 were brooding. Of these the number of eggs was counted from 25, the number ranged (range 22) from 3 to 25, with an average of 16, and a standard deviation of 5.9, and a median of 16 and a mode of 18 (Browne and Smith, 2004).

Sampling: Because the high populations of the Deep-body pipefish appear restricted to depths of less than 1.5m below low tide, and this species prefers sheltered areas it is easy to sample with a hand net. One site yielded 80 Deep-body pipefish in three hours, another 47 in one hour. At other inshore site and to some depth occasional Deep-body pipefish occur. However, because of the low population density these do not appear to be preferred habitat.

Conservation: Population concentrations of the Deep-body pipefish appear restricted to a limited number of inshore locations and a representative sample of these should be monitored. Because this inshore species tolerates extremes of temperature and salinity it could provide an indicator species for environmental change, particularly those affecting it food source or reproduction. The Deep-body pipefish should be good indicator species, as are some other inshore pipefish, as the both population dynamics and reproduction are relatively easy to monitor.