Fishes · Rays · Wedgefish

Whitespotted Wedgefish

Rhynchobatus djiddensis (Forsskål, 1775)

syn. Raja djiddensis, Rhinchobatus djiddensis, Rhinobatus djiddensis, Rhinobatus maculata, Rhynchobatis djiddensis, Rhynchobatus djeddensis +7 more

3.1 m1-70 mCITES IICritically Endangered

756

The Whitespotted Wedgefish (Rhynchobatus djiddensis) is a large species characterized by its distinctively pointed, somewhat bottle-shaped snout, with a length measuring 3.6-4.7 times the orbit length. It features spiracles with two short, equally-sized skin folds. The anterior margins of its disc are nearly straight or slightly undulating, while the pectoral apices are bluntly angular, and posterior margins remain straight. Notably, the species has prominent thorns in a continuous row along the midline, as well as around the eyes and above the spiracles. There are two thorn rows on each shoulder, with the upper row divided into two sections and the lower row being very short. Occasionally, there is a small cluster of thorns on the cheek.

In adults, the dorsal fins are tall and falcate, with the first dorsal fin being slightly larger than the second and originating anterior to the insertion of the pelvic fins. The caudal fin is large, featuring a deeply concave posterior margin and a well-defined lower lobe. A lateral keel extends along the posterior flank to the base of the caudal fin.

The dorsum of the Whitespotted Wedgefish ranges from dark grey to yellowish-brown, adorned with numerous small white spots or rings distributed along the flanks, extending from the ocelli level to the tail. These spots form 4-5 rows along the flanks, being more prominent in juveniles. The flanks typically exhibit large, dark ocelli equivalent in size to the spiracles, often found above the pectoral fin. A dusky or dark mask frequently appears across the eyes. These markings may vary in prominence or be absent altogether. The ventral side is white, often displaying small dark spots near the tip of the snout.

The species can reach a maximum length of 310 cm, with a size at birth of approximately 60 cm. It inhabits tropical and subtropical marine environments, predominantly demersal on soft substrates, occasionally adjacent to coral reefs, ranging from close inshore areas to depths of 70 meters.

Geographically, the Whitespotted Wedgefish is found throughout the 🌊 Indian Ocean, from 🇿🇦 South Africa to 🇴🇲 Oman and the Arabian Gulf. The occurrence of this species further east remains unverified due to challenges in distinguishing closely related wedgefish species.

Reproduction is aplacental lecithotrophic viviparous, with an average litter size of 4 offspring. The diet predominantly consists of demersal fishes, crabs, and bivalves.

This species exhibits migratory behavior. Tagged individuals in the region of KwaZulu-Natal (🇿🇦 South Africa), 🇿🇦 South Africa, have shown seasonal absence in winter, likely due to northward migration.

The Whitespotted Wedgefish has become rare along much of the east coast of Africa due to overfishing, although it remains relatively common in 🇿🇦 South Africa. Sightings often occur at dive sites in Sodwana Bay, and the species is frequently caught by beach fishermen in Zululand and KwaZulu-Natal (🇿🇦 South Africa), suggesting that dive sites along this coastline may be productive, particularly in the summer months. Conducting studies on the Whitespotted Wedgefish in these regions can provide valuable insights into its current population status and migratory patterns.

Why it's threatened

Biological resource use

Intentional use: (subsistence/small scale) [harvest] · Intentional use: (large scale) [harvest] · Unintentional effects: (subsistence/small scale) [harvest] · Unintentional effects: (large scale) [harvest]

Globally, wedgefishes are subject to intense fishing pressure on their coastal and shelf habitats that is unregulated across the majority of their distributions. Wedgefishes are captured in industrial, artisanal, and subsistence fisheries with multiple fishing gears, including gillnet, trawl, hook and line, trap, and seine net and are generally retained for their meat and fins (Bonfil and Abdallah 2004, White and Sommerville 2010, Moore 2017, Jabado 2018). There is a high level of fisheries resource use and increasing fishing pressure across the range of the Whitespotted Wedgefish, and demersal coastal fisheries resources have been severely depleted in significant areas of the Indian Ocean.

In general, fishing effort and the number of fishers has increased in recent decades across the range of this species, with demand for shark and ray product increasing over the same period due to the shark fin trade (Chen 1996, Jabado et al. 2017). In the Red Sea for example, the number of traditional boats tripled from 3,100 to 10,000 from 1988 to 2006 (Bruckner et al. 2011), and in Madagascar, the number of pirogues (small-scale fishing boats) rose from ~5,000 in 1983 to ~22,000 in 1996 (Cooke 1997). Most countries have significant fishing fleets operating in coastal waters e.g., Oman (19,000 artisanal boats) and Pakistan (2,000 trawlers) (Jabado et al. 2017).

Sharks and rays, including wedgefishes, are often targeted and now heavily exploited across the region by net and trawl fisheries and increasing fishing effort has put significant pressure on all wedgefish species in the Indo-West Pacific. Furthermore, the high value of fins is driving retention and trade of wedgefishes globally and the targeting of wedgefishes for their fins has also been reported in numerous countries, including Madagascar, Mozambique, and Tanzania (Cripps et al. 2015, Barrowclift et al. 2017, Moore 2017, Jabado 2018). The Whitespotted Wedgefish is landed throughout its range (e.g., Pierce et al. 2008, Humber et al. 2017, Jabado 2018), with the exception of South Africa, and its distribution includes Iran which ranks among the top 20 shark fishing nations globally (Lack and Sant 2011).

Illegal, unreported, and unregulated (IUU) fishing is known to occur in some parts of the range, for example by foreign and regional trawlers in Somalia and Yemen, with wedgefish specifically targeted off East Africa (IOTC 2005, Jabado et al. 2017).

In South Africa, the Whitespotted Wedgefish is caught in prawn trawl fisheries, shark bather protection nets, and recreational fisheries (Dudley and Cliff 1993, Fennessy 1994, Pradervand et al. 2011).

The shallow, inshore soft-bottom habitat preferred by the species is threatened by habitat loss and environmental degradation (Moore et al. 2012, Jabado et al. 2017, Moore 2017). In the Arabian Sea and adjacent waters, dredging and coastal land reclamation has increased in recent years and has resulted in almost total loss of mangroves in some areas, such as Bahrain (Sheppard et al. 2010, Jabado et al. 2017).

Threat classification from the IUCN Red List.