The Red Wide-bodied Pipefish (Stigmatopora harastii) is a small (up to 14.5 cm) pipefish that occurs in the Southwest Pacific at depths of 11–18 m. It has been observed living in facultative associations with finger sponges and red algae. This pipefish is threatened by habitat degradation from coastal development, pollution, sedimentation, and climate change. There are no population estimates to date, but population reduction, if any, is suspected to be at a level that would not approach the threshold for a threatened assessment under criterion A. However, this species has an extent of occurrence of 2,700 km², it is estimated to occur in fewer than five locations, and it is undergoing a continuing decline in habitat quality. Therefore, the Red Wide-bodied Pipefish is assessed as Endangered under criterion B (EN B1ab(iii)).

The Red Wide-bodied Pipefish occurs in the Southwest Pacific. It has been recorded in only four localities in New South Wales, Australia: Botany Bay, Cronulla, Shellharbour, and Jervis Bay. It may have a wider distribution in similar habitats across New South Wales, southern Australia, and New Zealand (GBIF 2023, Short and Trevor-Jones 2020). Based on its currently known range, this pipefish has an extent of occurrence (EOO) of approximately 2,700 km².

There are no dedicated surveys or population estimates for the Red Wide-bodied Pipefish to date. It is suspected that its population in Botany Bay is quite small, given the low density of red algae that it associates with and the low pipefish-to-algae ratio (A. Trevor-Jones unpub. data 2024).

Given low-level declines in its habitat quality, the population size of this pipefish is suspected to have declined at a level that has not approached the threshold for a threatened assessment under criterion A.

The Red Wide-bodied Pipefish is a marine pipefish that inhabits semi-exposed habitats, comprising sandy bottoms, boulders, and flat reefs, at depths of 11–18 m (Short and Trevor-Jones 2020). It has been observed living in facultative associations with finger sponges from the family Callyspongiidae and red algae from the genera Crassiphycus and Gracilaria (Short and Trevor-Jones 2020).
 
It has a maximum recorded total length of 14.5 cm (Short and Trevor-Jones 2020). Its feeding behavior is similar to other Stigmatopora species, where it captures small copepods and shrimp by darting out of its algae cover (Short and Trevor-Jones 2020). It is ovoviviparous, and brooding occurs in the male brood pouch under the tail (Short and Trevor-Jones 2020).

The Red Wide-bodied Pipefish is threatened by habitat degradation. Coastal and marine ecosystems across Australia, including New South Wales, are affected by multiple pressures such as coastal development, pollution (e.g. wastewater, agricultural runoff), sedimentation, and climate change (Clark et al. 2021, Clark and Johnston 2017, Evans et al. 2017, Fletcher and Fisk 2017, NSW Environment Protection Authority 2018). In New South Wales, most coastal and marine environments were assessed as being in good condition in 2018 (NSW Environment Protection Authority 2018). However, increasing development and settlements along the coasts continue to threaten biodiversity in the region (NSW Environment Protection Authority 2018). There have also been significant flood events in New South Wales in 2020 and 2021, which have had detrimental impacts on marine life (Davis et al. 2022). 

The finger sponges and red algae that the Red Wide-bodied Pipefish associates with may be negatively affected by habitat modifications, eutrophication, sedimentation, and climate change (Bell et al. 2015, Clark et al. 2021, Clark and Johnston 2017), but their declines, if any, have not been quantified. Sponges in general are less affected by ocean warming or acidification than other benthic organisms such as corals and may benefit from near-future climate scenarios, but tolerance to changing conditions varies between species (Bell et al. 2018). An increase in storm frequency and intensity can cause significant damage to shallow habitats, but storms may facilitate asexual reproduction in sponges through fragmentation (Bell et al. 2018). In Botany Bay, the density of red algae with which this pipefish associates has been observed to vary greatly throughout the site and over time, but the cause of this variation is unclear (Short and Trevor-Jones 2020). Gracilaria algae are also able to adapt to variable growing conditions, such as increased nutrient inputs and higher water temperatures (Qin 2018).

Given the pressures affecting coastal and marine ecosystems across its range, it is inferred that there has been a decline in the quality of the Red Wide-bodied Pipefish’s habitat, but that this has likely not led to substantial reductions in population size.

The Red Wide-bodied Pipefish has not been recorded in trade. It is unlikely to be targeted by fisheries as its remarkable crypsis among finger sponges and red algae can make it challenging to find. 

The Spotted Pipefish (S. argus) and the Wide-bodied Pipefish (S. nigra) have been observed in aquarium displays and aquaculture in Australia, and the former has also been recorded as a target and bycatch species in Australian fisheries (McClatchie et al. 2006). Other pipefishes are traded for aquaria, curios, or traditional medicine in Australia, but trade is thought to occur at very low levels (Martin-Smith and Vincent 2006, Vincent et al. 2011).

The level of offtake of the Red Wide-bodied Pipefish, if any, is unknown but is suspected to be low.

In New South Wales, all Syngnathiformes are listed as protected under the NSW Fisheries Management Act 1994 and it is illegal to catch and keep or possess Syngnathiformes without a permit or licence, and heavy penalties apply.

It is not listed under any international legislation or trade regulations. 

The pipefish occurs in at least two protected areas (e.g. Kamay Botany Bay National Park, Jervis Bay Marine Park) (Short and Trevor-Jones 2020, UNEP-WCMC and IUCN 2022).

Further research is needed to determine its population size, trends in abundance, and habitat trends. Regulating coastal development and pollution and monitoring habitat conditions are necessary for the conservation of this species.