Smalltooth Sawfish
Pristis pectinata
Profile / Morphology 2
All modern sawfishes appear in some respects to be more shark-like than ray-like, with only the trunk, and especially the head, ventrally flattened. The presence of an extended rostrum (snout) having laterally protruding teeth is the main feature that separates all sawfishes from sharks and rays. The rostrum has a saw-like appearance, hence the name of sawfish.
Diet 3
Smalltooth sawfish feed on benthic invertebrates and small schooling fishes. The saw is used for grubbing prey in the sediment and for attacking prey (usually schooling fishes) as well as for defense.
Average lifespan in the wild 3
40 - 70 years
Size / Weight 3
25 feet (7.6 meters) maximum (adult female) / 1200 lbs (544 kg) maximum
Habitat 3
Pristis pectinata is known from tropical and warm temperate nearshore ocean waters. Juveniles are common in very shallow waters, but adults occur to depths over 330 ft (100 m). They are thought to spend most of their time on or near the seabed, but they occasionally swim at the surface. There are many records from coastal lagoons, estuarine environments and the lower, brackish drainages of rivers. Different populations of smalltooth sawfish spend more or less time in freshwater areas, but they are less well-adapted to freshwater than other sawfishes. However, they are generally more tolerant than most fishes to a range of environmental conditions but they generally prefer soft-sediment habitats in nearshore areas.
Range 3
They occur in the Western Atlantic from North Carolina to the Gulf of Mexico and Brazil. They also occur in the Eastern Atlantic and Mediterranean Sea. Thus, this is possibly the most widespread Pristis species, even though populations are highly disjunct.
Reproductive / Life span 3
These sawfish are ovoviviparous, which means they have live birth but the young are nourished only with yolk provided to the egg at the beginning of development (i.e., there is no placenta). Females produce an average of 15 to 20 individual young per year. The gestation period is approximately 5 months. Maturity occurs around 10 years of age while size at maturity is estimated as 10.5 ft (320 cm) in length.
Maximum life span is estimated to be 40 to 70 years and generation times are approximately 27 years
Relatives 3
The smalltooth sawfish and the largetooth sawfish (Pristis perotteti) are similar in appearance and overlap in their ranges. The two species can usually be differentiated by noting the number of teeth on one side of the rostrum. P. perotteti can have between 14 and 21 rostral teeth on one edge of the saw, whereas P. pectinata usually has 23 to 34 teeth. These two species can also be distinguished by observing that in P. perotteti the first dorsal fin originates in front of the pelvic fins, while in P. pectinata the first dorsal fin originates along the same axis as the pelvic fins. The pectoral fins of P. perotteti are also proportionally larger than those of P. pectinata. Furthermore, only P. perotteti has a distinct lower lobe on its caudal fin (McEachran and Fechhelm 1998, Compagno and Last 1999).
Found in the following Estuarine Reserves 3
Mission-Aransas (TX), Grand Bay (MS), Weeks Bay (AL), Appalachicola (FL), Guana Tolomato Matanzas (FL), Sapelo Island (GA), ACE Basin (SC), North Inlet Winyah Bay (SC).
Water quality factors needed for survival 3
•Water Temperature: 18-30°C
•Turbidity: low to high
•Water Flow: no data, adults likely tolerant of high flows
•Salinity: varies
•Dissolved Oxygen: unknown
Threats 3
Threats •Excessive fishing
•Bycatch
•Habitat degradation
Sawfish populations are becoming increasingly rare and fragmented and all those that are known are severely threatened by target and bycatch fisheries and deterioration of habitats. Many populations have been extirpated or nearly extirpated from large areas of their former range. There have been no or only a very few observations reported in most range states since the 1960s, although sawfish were reportedly common in many inshore waters at the end of the 19th century and early 20th century. The portion of the population that used to disperse north along the eastern coast of the U.S. as far north as New York may have been completely lost. Bycatch rates in The Gulf of Mexico population of sawfish are severely reduced with isolated and very small populations, perhaps totaling a couple of thousand individuals, remaining off Florida and perhaps venturing to adjacent waters. This compares with estimates of hundreds of thousands in the late 1800s (Simpfendorfer 2002). Smalltooth sawfish are relatively common only in the Everglades region at the southern tip of the state. Louisiana shrimp trawlers declined steeply during the late 1950s and early 1960s and none have been reported since the 1970s (Simpfendorfer 2002).
Smalltooth sawfish have low intrinsic rates of increase, which means they experience slow population growth. This makes them particularly vulnerable to excessive mortalities and rapid population declines, because recovery from such events may take decades. Incidental commercial catch was likely the most significant factor in the decline of sawfish populations in U.S. waters. Sawfish are extremely vulnerable to overexploitation due to their exceptional propensity for getting entangled in net gear and because of their restricted preferred habitat. Habitat degradation likely impacts the species given their inshore distribution and human activities in those areas.
Juvenile sawfish use shallow habitats with a lot of vegetation, such as mangrove forests, as important nursery areas. This type of habitat has been greatly modified or lost due to development of the waterfront in Florida and other southeastern states. The loss of juvenile habitat has likely contributed to the decline of this species.
Conservation notes 3
Importance to Humans and Estuaries
There were small commercial and recreational fisheries for this species for both food and parts. There is a small curio trade for their unique rostrum (saw).
How to Help Protect This Species
Because this species uses estuaries and freshwater areas they are susceptible to water pollution and damage to and alteration of stream channels and riparian zones. Therefore, efforts to minimize runoff of pollutants, fertilizer, and sediment from your neighborhood into local streams are helpful to this species or other stream and estuary dwelling species in your area. Join a stream or watershed advocacy group in your area to protect your local estuary ecosystems including advocating for restoration of more natural water flow regimes. Support research into the ecology and conservation of the species. The states of Florida, Louisiana, and Texas have prohibited the "take," or possession, of sawfish
Sources and Credits
- (c) Cliff, some rights reserved (CC BY), http://www.flickr.com/photos/28567825@N03/2877072682
- Adapted by GTMResearchReserve from a work by (c) Wikipedia, some rights reserved (CC BY-SA), http://en.wikipedia.org/wiki/Pristis_pectinata
- (c) GTMResearchReserve, some rights reserved (CC BY-SA)
