Shark Research - Saudi Arabian Shark Fisheries not sustainable

A recent article published in Fisheries Research sheds light on our knowledge of shark fisheries in Saudi Arabia and indicates that these Red Sea fisheries are unsustainable.

The researchers, from King Abdullah University of Science & Technology (KAUST) and Woods Hole Oceanographic Institute, spent 2 years collecting samples from the Jeddah Fish Market (JFM) in the Kingdom of Saudi Arabia (KSA). During this time the team collected 2,724 individual samples across 37 species of elasmobranch. Seventy three per cent of the entire sample was made up of only 5 species: the spottail shark (Carcharhinus sorrah), the grey reef shark (C. amblyrhynchos), the silky shark (C. falciformis), the black tip shark (C. limbatus) and the milk shark (Rhizoprionodon acutus). Of these 5 species, 4 are classified as Near Threatened in the IUCN Red List.

Sharks for sale at the Jeddah Fish Market. Image from the daaamnblog

Perhaps most worryingly, the researchers discovered that a very large percentage (c. 81%) of the males caught had not yet reached sexual maturity. This is a cause for concern as if too many juveniles of a species are removed from a fish stock then the stock itself will be unable to replenish itself and will risk collapse.

The sharks were landed whole and whilst the fins were removed, this was done when the shark was back on land and the meat was then sold; however, the team noted that the cost of shark meat, compared to other fish, appeared to be very cheap in the KSA.

Whilst in many countries sharks may be considered more valuable alive than dead, owing to a boom in the eco tourism industry, the distinct lack of tourism in the KSA has not incentivised the government to implement and enforce policies regarding shark protection, despite the fact that the resources to carry out adequate shark management should not be unobtainable for the KSA.

Shark News - Rare Frilled Shark Caught in Australia

A lot of excitement seems to have been generated today by the capture of a frilled shark (Chlamydoselachus anguineus) off the coast of Victoria, Australia. The frilled shark is an incredibly rare species and one of only 2 in its genus (the other being the South African frilled shark Chlamydoselachus africana.)

Image from SETFIA http://www.setfia.org.au/item/living-fossil-captured.html

Don't worry though - despite the portrayal of this amazing species in most media stories as a "terrifying frilled shark from the deep", this shark isn't actually considered harmful to humans. For a start their principal diet consists of squid and crustaceans...and secondly they are a deep water species most commonly found at 500-1,000m.

Very little is known about this shark, which is why the South East Trawl Fishing Industry Association (SETFA) have reported that the animal was offered to the Commonwealth Scientific & Industrial Research Organisation (CSIRO) for data capture.

This animal has been classified as Near Threatened by the IUCN Red List as it is occasionally caught as bycatch - primarily by the bottom trawl and deep-set longline fisheries (which is why it is not overly surprising that this specimen was caught in trawler nets). There is concern that the frilled shark would be vulnerable if deepwater fisheries are expanded.

The frilled shark doesn't really have many close relatives still living today, but it is classified amongst the Hexanchiformes - an Order which includes several species of rare and wonderful shark such as the six gill and seven gill sharks. The frilled shark itself also has six gills making this group a little different from the rest of the sharks - most of which have 5 gills.

I wanted to include a nicer picture of a frilled shark rather than the - quite frankly unflattering one! - which has been attached to these news stories.

Image from Arkive http://www.arkive.org/frilled-shark/chlamydoselachus-anguineus/image-G38906.html