Apron  (Zingel asper)

The apron is classified as Critically Endangered (CR) on the IUCN Red List (1).

The elusive apron (Zingel asper) is a small and highly mobile fish. It is usually light brown or dark grey, with a patterning of mottled dark grey spots on its head. It also has irregular darker stripes running downwards along its body, allowing it to blend in with the gravel beds of the streams it inhabits (4). The apron can be differentiated from related species by its two dorsal fins, each of which has a number of rigid spines (5).

The apron is now restricted to four subpopulations in the basin of the Rhone River in the southeast of France and Switzerland (4).

Found in moderately fast flowing streams and rivers, the apron prefers waterways with gravely or stony bottoms, and containing sandbanks or riffles for breeding (5).

Not much is known about the behaviour of the apron, but it is believed to behave in a similar way to the closely related streber (Zingel streber), which lives in small colonies or schools of several individuals that have territories scattered through the habitat (4). The apron lurks on the bottom of the river bed during the day, coming out to feed at twilight (6). Its diet consists of different types of invertebrates, consuming flies and midges in winter, and mayflies and caddisflies during the rest of the year. Most of the feeding and growth of this species occurs during the spring and summer (7).

The apron is a relatively short lived species, surviving for just three and a half years. This species attains sexual maturity at two to four years of age (6). It usually reproduces only once, but can reproduce twice in a lifetime (1). The apron spawns in the deeper parts of riffles, laying its small, extremely adhesive eggs onto the gravel stream floor. The eggs hatch within two weeks and the larvae feed on plankton near the surface until they reach a length of about two and a half centimetres. They then move to deeper water (5).

The apron is threatened by water pollution and habitat destruction (1). It is facing increasing fragmentation of populations due to damming of the river, in which they are endemic, to produce hydroelectric power (8).

The plight of the apron has been recognised internationally by the European Union and its habitat has now been protected (9). Conservation measures also include a ban on catching this fish, and there are proposals to reintroduce the apron into parts of the river to reduce the fragmentation of the population (4) (8).

View information on this species at the UNEP World Conservation Monitoring Centre.

More information on the apron:

• FishBase - Apron:
  http://www.fishbase.org/summary/Zingel-asper.html