Thicklip mullet  (Chelon labrosus)

The thicklip mullet is classified as Least Concern (LC) on the IUCN Red List (1).

The thicklip mullet (Chelon labrosus), named for its extraordinarily thick, swollen-looking upper lip, is a fairly common fish in seas around Europe (3) (4). It has an elongated, cylindrical-shaped body with a notably broad, flattened head and a forked tail (5) (6). The two dorsal fins are short and widely separated, with the spiny first fin having four slender spines and the softer second having nine or ten soft rays (3) (5). The pectoral fins are positioned rather high up the body (5). The thicklip mullet is dark grey above, often with a greenish tinge, silver on the underside, and light grey with long, dark smudges on the sides. The fins are dark grey in colour (6).

The thicklip mullet is found in the Eastern Atlantic, ranging from Cape Verde and Senegal to southern Norway, southern Iceland and the Faroe Islands, and eastwards to the Mediterranean Sea and the western Black Sea. Since the mid-1960s its range has steadily expanded from the North Sea into the western Baltic Sea (1) (3) (6).

With a broad tolerance of different salinities and temperatures, the thicklip mullet resides in coastal and estuarine waters during the spring and summer and migrates to deeper offshore waters before winter (1) (3) (4) (6).

The thicklip mullet breeds in deep, offshore waters between July and August in British and Irish waters, but earlier in the year in more southerly parts of its range. Eggs and sperm are released simultaneously into the water, with the developing larvae subsequently floating in the water currents as part of the zooplankton community (3). When they reach around two centimetres in length, the young fish move to sheltered coastal lagoons and estuaries (1) (3). They reach sexual maturity at around 30 to 35 centimetres in length and an age of 2 to 4 years, with the male fish first breeding before the females (1) (3).  The thicklip mullet is reported to live for up to 12 years (1). 

Whilst travelling in large schools, adult thicklip mullets feed on algae, aquatic plant detritus and small invertebrates. The juveniles feed on zooplankton (3). 

A widespread species, there are not thought to be any major threats to the thicklip mullet, although information on its abundance is limited (1) (2). It is a valued commercial fish species and is harvested for food across its range (7). 

As a fairly important commercial fish species, regulations are in place to control the size of thicklip mullets which can be harvested and, as such, fish under 35 centimetres in length may not be taken (2) (7).

ARKive is supported by OTEP, a joint programme of funding from the UK FCO and DFID which provides support to address priority environmental issues in the Overseas Territories, and Defra

To find out more about the conservation of fish, see:

• Fish Online:
  http://www.fishonline.org/