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Syngnathus watermeyeri 

Scope: Global
Language: English
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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Actinopterygii Syngnathiformes Syngnathidae

Scientific Name: Syngnathus watermeyeri Smith, 1963
Common Name(s):
English Estuarine Pipefish, Estuarine Pipefish, River Pipefish
Taxonomic Source(s): Smith, J. L. B. 1963. Fishes from the family Syngnathidae from the Red Sea and western Indian Ocean. Ichthyological Bulletin 27: 515-543.

Assessment Information [top]

Red List Category & Criteria: Critically Endangered C2a(i)b ver 3.1
Year Published: 2017
Date Assessed: 2016-05-25
Assessor(s): Pollom, R.
Reviewer(s): Ralph, G. & Whitfield, A.
Contributor(s): Sorensen, M., Bills, R. & Whitfield, A.
Justification:

Syngnathus watermeyeri is an estuarine pipefish species that inhabits seagrass beds and macrophytes, and is endemic to the Bushmans, Kariega, and Kasouga estuaries on the Eastern Cape coast of South Africa. The species is dependent on regular freshwater influxes, which have become more sporadic due to human alterations and water mismanagement in the region, leading to a decline in mature individuals. The species has been listed as Critically Endangered under criterion C2a(i)b due to a continued decline in habitat quality and the absence of mature individuals in the latest intensive surveys. It is also likely that there are less than 250 animals in total and 50 mature individuals or less in each estuarine subpopulation, with extreme fluctuations. Until a programme is in place that regulates freshwater pulses into South African estuaries, which are needed to maintain the S. watermeyeri food supply, the species will likely remain at high risk of extinction. Population and habitat monitoring are needed. 

Previously published Red List assessments:

Geographic Range [top]

Range Description:

Syngnathus watermeyeri is known only from the Bushmans, Kariega, Kasouga, and East and West Kleinemonde estuaries on the Eastern Cape coast of South Africa (Dawson 1985, Whitfield 1995, Cowley 1998, Vorwerk et al. 2007). Based on information collected between 2010 and 2015, currently it occurs in only two locations: the Bushmans and Kariega estuaries (A. Whitfield pers. comm. 13 March 2017).

Countries occurrence:
Native:
South Africa (Eastern Cape Province)
FAO Marine Fishing Areas:
Native:
Atlantic – southeast; Indian Ocean – western
Additional data:
Number of Locations:2Continuing decline in number of locations:Unknown
Extreme fluctuations in the number of locations:Yes
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:

Syngnathus watermeyeri has been recorded in small numbers and its presence/absence in surveys has fluctuated dramatically since these surveys began. Initial surveys in 1963 found 10 Estuarine Pipefish in the Bushmans estuary, 11 in the Kariega estuary and two in the Kasouga estuary (Whitfield 1995). Between 1989 and 1992, intensive surveys were conducted in all three estuaries with no specimens recorded. As a result, S. watermeyeri was listed as officially Extinct in the 1994 IUCN Red List but in 1996 a new breeding population was discovered in the East Kleinemonde estuary (Cowley 1998). This new population, however, was declared locally extinct in 2003 when a large flood destroyed their preferred aquatic macrophyte (Ruppia cirrhosa) habitat in that system. No specimens have since been found in the East Kleinemonde (James et al. 2008).

The most recent surveys occurred in 2006 and found juvenile S. watermeyeri once again in its historic range (Bushmans and Kariega estuaries) where it had not been reported for over four decades (Whitfield and Bruton 1996). These intensive surveys found a total of 20 specimens in the Kariega estuary, ranging from 0.05 to 0.2 individuals m-2 (Vorwerk et al. 2007). Peaks in abundance were found in areas where mesohaline conditions prevailed and the percentage vegetation cover exceeded 80% (Vorwerk et al. 2007).

Currently it is likely that fewer than 50 individuals exist in each estuarine subpopulation, and therefore the species qualifies for listing as Critically Endangered under criterion C2a(i).

Current Population Trend:Decreasing
Additional data:
Number of mature individuals:100-250Continuing decline of mature individuals:Yes
Extreme fluctuations:YesPopulation severely fragmented:Unknown
No. of subpopulations:2Continuing decline in subpopulations:No
Extreme fluctuations in subpopulations:UnknownAll individuals in one subpopulation:No

Habitat and Ecology [top]

Habitat and Ecology:Syngnathus watermeyeri occurs in brackish, tidal areas of estuaries and is found primarily in association with the eelgrass Zostera capensis and the aquatic macrophyte Ruppia cirrhosa, where it feeds almost exclusively on zooplankton (Whitfield 1995). The species undergoes large fluctuations depending on macrophyte presence or absence, and generally is only found when they are present (Sheppard et al. 2011).

The species is ovoviviparous, and the male carries the eggs in a brood pouch which is found under the tail (Breder and Rosen 1966). Sexual maturity is attained at approximately 10 cm standard length with males retaining up to 44 embryos (Mwale et al. 2014). Reproductively active specimens were collected in the Kariega estuary during late September (Whitfield 1995).
Systems:Freshwater; Marine
Continuing decline in area, extent and/or quality of habitat:Yes
Movement patterns:Not a Migrant

Use and Trade [top]

Use and Trade: Although pipefishes in general are often traded for use in traditional medicine (Vincent et al. 2011), this species has not been recorded and is not likely to be targeted or caught as bycatch.

Threats [top]

Major Threat(s): Syngnathus watermeyeri relies on freshwater pulses which provide the nutrients that enable phytoplankton development and, together with particulate organic material brought down by the rivers, support the zooplankton community upon which these pipefish depend for food. The construction of dams and other impoundments have caused a deprivation of fresh water pulses and a subsequent decline in food supply (Whitfield 1995). Dry conditions in the late 1900s and early 2000s, together with excessive freshwater abstraction from the catchment, caused the Kariega river to stop flowing, which probably contributed to the absence of S. watermeyeri from this system during this period (A.K.Whitfield pers. comm. 13 March 2017).

This species may also be particularly susceptible to hypersaline conditions and to large flood events (Vorwerk et al. 2007). A flood event in the East Kleinemonde estuary in 1996 (Cowley 1998) resulted in the apparent localized extinction of S. watermeyeri. This was thought to be the result of primary S. watermeyeri habitat, submerged Ruppia cirrhosa beds, being flushed out to sea (Vorwerk et al. 2007). A similar occurrence of Zostera capensis destruction in the Kariega estuary during 2012 caused the demise of recovering estuarine pipefish populations in this system (A.K. Whitfield pers. comm. 13 March 2017).

Conservation Actions [top]

Conservation Actions: There are no species-specific conservation measures in place for S. watermeyeri. The South African National Water Act 1998 (Act 36) requires that all rivers should have an Ecological Reserve amount set aside. The Ecological Reserve relates to "the water required to protect the aquatic ecosystems of the water resource", including both rivers and estuaries (Vorwerk et al. 2008a). Ecological reserves have been determined for some systems in South Africa but not for any estuaries inhabited by S. watermeyeri. When dams were built on the Kariega and its tributary rivers, a water release policy was issued for downstream agriculture but the environmental requirements of estuaries and rivers were not included (Vorwerk et al. 2008a).

This species does not occur in any protected areas, and it is not listed in any international legislation or trade regulations.

Citation: Pollom, R. 2017. Syngnathus watermeyeri. The IUCN Red List of Threatened Species 2017: e.T41030A67621860. . Downloaded on 18 December 2017.
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