Explore by Animal
Getting a glimpse of Ginsu, Shedd’s green sawfish, is a treat worth waiting for. Standing before Wild Reef’s shark habitat, your head tilted back to look for her undulating 14-foot form overhead is like watching a carousel for the most beautiful horse to pass by again. When she suddenly appears, she is stunning.
Seeing Ginsu at Shedd is also a privilege. Green sawfish (Pristis zijsron) are rare in aquariums because they are rare in the wild. While significant numbers still occur off northern Australia, in recent years populations have declined elsewhere throughout the species’ range in the coastal waters of the Indian and western Pacific Oceans.
In 2006, the green sawfish was reevaluated from endangered to critically endangered—one step away from extinct in the wild, and two steps away from extinct altogether—by the International Union for Conservation of Nature and Natural Resources (IUCN). Trade in green sawfish was banned by an international wildlife treaty.
Only public aquariums are permitted to acquire them—made available in low, sustainable numbers by the Australian government—so that people can learn more about this magnificent animal and its plight.
This is the largest of the sawfish species, typically growing to a length of 18 feet; a record-setting male reached 24 feet. They grow fast: Ginsu, who was 6 feet long when she arrived at Shedd in 2003, is about 14 feet and still adding inches. (Aquarists couldn’t resist naming her for a kitchen knife that was marketed through late-night television ads that ran ad nauseam in the late 1970s.)
Although sawfish have sharklike bodies, they are more closely related to rays. All have cartilage skeletons instead of hard bones. The green sawfish is distinguished by its greenish brown skin and long, tapering saw, or rostrum. Either side of the saw is studded with 25 to 34 sharply pointed toothlike scales that stick straight out from the edge.
Swimming in shallow water, the fish swipes its saw from side to side to stir up crabs and prawns from the muddy sea floor or plows into schools of reef fishes, whacking and wounding them, then circling back to pick up the casualties. As if the saw were not enough, these fish also have small, rounded teeth in the mouth, probably good for grasping.
At Shedd, Ginsu has learned that five taps of a pair of long tongs against the side of her habitat means dinner is served. She also responds to a visual cue, a blue-and-white square placed in the water. She gets mullet (her favorite), herring, Spanish mackerel and bonito, all fortified with multivitamins.
For such large fish, it might be surprising that green sawfish prefer shallow inshore waters, including estuaries, bays and lagoons no more than 20 feet deep. Unfortunately, these are also heavily exploited commercial fishing grounds. Prawn trawls and gillnets take a high toll on green sawfish, which get entangled by the rostrum. And despite the trade ban, sawfish are also intentionally taken for their meat, fins and rostrums, the last sold as costly curios or used in traditional Asian medicine. Coastal development, resulting in habitat loss and pollution, has also contributed to this fish’s decline.
Green sawfish have few natural predators. And despite their fearsome appearance, they pose little danger to humans if they are left alone.
But don’t pass by Ginsu! She’s a breathtaking beauty and one of Shedd’s most amazing animals, definitely worth waiting to see.