Indicator Species:

Their presence can help to determine and monitor the health of a piece of coastline or an estuary. Reduced pipefish numbers could be a warning. If their numbers fall, we need to sound the alarm. Pipefish are adversely affected by environmental changes because of their restricted distributions, low mobility, small home ranges, and relatively low and slow reproduction rate. Habitat loss or alteration, therefore, seriously threatens their survival. The construction of housing and jetties on estuarine banks has reduced the distribution and abundance of eelgrass habitats that are critical for pipefish as nursery areas, feeding grounds, and shelter from predators. Although they may live in various habitats and have a moderately large geographical range, their complex life history and reproductive strategies make them highly vulnerable when their environments are altered.

The two species that are endemic to southern African coastal and estuarine waters are the long snout pipefish, Syngnathus temminckii, and the estuarine pipefish (also known less accurately as the river pipefish), S. watermeyeri which is not well understood. (The taxonomic status of most species of this genus is unclear.)

Like seahorses, they are uniquely different from most organisms, in that males rather than females take responsibility for bearing and rearing their young.

Reproduction:

The male receives eggs from a female and carries them on his body surface or inside a specialized brood pouch under his trunk or tail. This ‘pregnant’ male fertilizes the eggs, provides nutrition and oxygen to the developing embryos for up to a month, and gives birth to live young. Paternal care and investment in reproduction is therefore substantial, while maternal care is slight or even nonexistent, as all the females do is provide the eggs. Thus the usual sex roles are reversed, and the females compete with one another in mating rituals.

Pregnant females display themselves vigorously by swimming up and down well above the seagrass beds, often in groups, while the males typically swim within the eelgrass from which position they select the most suitable mate. As a result, females have a higher potential reproductive rate than males – they produce more eggs than the males can brood during an equivalent period of time, and they can contribute eggs to more than one male. The males, on the other hand, are more choosey in selecting females (to ensure reproductive success), as the length of their brooding cycle or ‘pregnancy’ limits the number of times they can mate. The relatively low fecundity and long period of parental care makes pipefish vulnerable when their habitat is disturbed.

Conservation Status:

Pipefish are approuaching the 'near threatend' status on the IUCN Red List. Researchers tried to save and collect stranded pipefish in the East Kleinemonde river basin drained of water in August 2001 by artificial breaching to protect housing built below the flood line. About 50% of the biomass (vegetative macrophytes, fish, and invertebrates) was exposed and died. Most estuarine systems are now artificially opened by breaching because local developments have altered the freshwater flow patterns into these systems, thus affecting their natural opening and closing dynamics. Estuaries are artificially breached by means of a channel dug across the sand barrier (berm) to a level below the water level in the impoundment. Artificial breaching can make water levels drop from 2.8 m above sea level to 0.2 m below sea level in just a few hours, creating large and rapid changes in the environment, which, in turn, trigger major biological responses and damage to fish and other life.

FUN FACT!

Most pipefish live in tidal pools and other coastal habitats. However, one species lives in the intestine of a species of sea cucumbers!