Green Sawfish (Pristis zijsron)
Did You Know?
· Green sawfish can have 25-32 teeth on each side of their "saw," or rostrum.
|Length:||up to 23 ft (7 m); typically 15 ft (4.5 m)|
|Appearance:||known for their "saws," long, thin flat snouts edged with pairs of teeth, greenish upper body coloration|
|Lifespan:||~50 years; maturity is reached at 10-12 ft (3 – 3.6 m) and 5-9 years|
|Diet:||mostly fish, but also crustaceans and mollusks|
|Behavior:||"ovoviviparous", meaning the mother holds the eggs inside of her until the young are ready to be born; gestation lasts 5 months and littler sizes range from 1-12 pups|
Sawfish, like sharks, skates and rays, belong to a group of fish called elasmobranchs, whose skeletons are made of cartilage. Sawfish are actually modified rays with a shark-like body and gill slits on their ventral (abdominal) side.
Early sawfish, distant cousins to modern day sawfish, first appeared in the ocean around 100 million years ago. Today's "modern day" sawfish species have been in the ocean around 56 million years.
Sawfish get their name from their rostrum or "saws"--long, flat snouts edged with pairs of teeth which are used to locate, stun, and kill prey. The green sawfish is also known as the narrow snout sawfish because it's rostrum is thinner than other sawfishes. Their rostrum is also relatively longer than other sawfishes and can comprise 20-30% of their total length. Their diet includes mostly fish but also some crustaceans and mollusks.
In Africa, the species can be confused with the similar smalltooth sawfish (P. pectinata).
Some genetic data suggests green sawfish may show philopatry, where adult females return to or remain in the same area they were born.
Green sawfish are generally restricted to shallow (less than 33 ft (10 m)) coastal and estuarine habitats, although they have been found in freshwater up to 150 miles upriver and to depths of 130 ft. Like most sawfishes, the green sawfish prefers muddy bottoms in estuarine environments.
The green sawfish historically ranged throughout the Indo-West Pacific from South Africa northward along the east coast of Africa, through the Red Sea, Persian Gulf, southern Asia, Indo-Australian archipelago, and east to Asia as far north as Taiwan and southern China. Green sawfish range has contracted and they are currently presumed to be extirpated in the Indian Ocean and the only recent records in the Indo-Pacific area outside of Australia are from Malaysia. In Australia recent records of the species are from the north and northwest coasts, especially the Gulf of Carpentaria. There is anecdotal evidence the species still occurs in the Persian Gulf and Red Sea (e.g., Sudan).
No robust estimates of historic or current population size exist. However, available data, museum and catch reports, and other records indicate that the species' distribution has been greatly reduced and that the population numbers have declined dramatically.
- entanglement in nets, lines, and trawls
- bycatch in fisheries, though in some areas they have been directly targeted
- loss of habitat
- juvenile sawfish use shallow habitats as important nursery areas, many of these have been modified or lost due to development
- inadequate regulatory mechanisms
Their low rate of population growth has also likely contributed to their decline.
All sawfish (Pristidae) species are listed on Appendix I of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). Appendix I limits international trade in species to exceptional circumstances only.
In September 2010, NOAA's National Marine Fisheries Service (NMFS) received a petition from WildEarth Guardians requesting that this species be listed under the ESA. On June 4, 2013, NMFS published a proposed rule to list the species as endangered.
|12-Month Finding and Proposed Endangered Listing of Five Species of Sawfish||78 FR 33300||06/04/2013|
|90-day finding on Petition, Initiation of Status Review||76 FR 12308||03/07/2011|
|Petition to list Six Species of Sawfish||n/a||09/07/2010|
- IUCN Red List Species Information
- Florida Museum of Natural History Species Information
- Fishbase Species Summary
Updated: August 15, 2013