Movements of juvenile endangered smalltooth sawfish, Pristis pectinata, in an estuarine river system: use of non-main-stem river habitats and lagged responses to freshwater inflow-related changes

作者：Poulakis Gregg R^*; Stevens Philip W; Timmers Amy A; Stafford Christopher J; Simpfendorfer Colin A

来源：Environmental Biology of Fishes, 2013, 96(6): 763-778.

DOI：10.1007/s10641-012-0070-x

• Acoustic monitoring
• Caloosahatchee River
• Charlotte Harbor
• Elasmobranch
• Generalized additive model
• Ontogenetic niche shift
• Pristidae
• Telemetry

The smalltooth sawfish (Pristis pectinata) is one of seven critically endangered sawfishes worldwide that little is known about beyond their presence in estuaries and rivers primarily during early life history. Movements of 24 juvenile P. pectinata (%26lt; 3 years old) were monitored over more than 2 years using acoustic tags and an array of 33 acoustic receivers. The receivers were distributed in both main-stem river habitats, which are known to be used by this species, and non-main-stem habitats (i.e., natural mangrove-lined creeks, seminatural creeks, seawall-lined canals) of the highly altered, flow-managed tidal Caloosahatchee River, Florida to determine (1) the extent of non-main-stem habitat use and (2) responses to freshwater inflow-related changes by P. pectinata. Twenty P. pectinata used non-main-stem habitats, and 11 used these habitats more than 10 % of the time, which has implications for management within the federally protected nursery area. The daily activity space of P. pectinata was 0.7 km of river distance, which is similar to that of other demersal ray species. There was little evidence that P. pectinata left the river and returned; they remained in the nursery under a wide range of environmental conditions. The distribution of all P. pectinata combined was significantly related to 90-day lagged salinity; sawfish moved upriver as salinity increased. Salinity patterns within the river had a greater effect on the distribution (mean river position) of %26lt; 1-year-old P. pectinata (90-day lagged salinity) than on that of older individuals (120-day lagged salinity). These results provide further evidence of the importance of this system as a nursery and provide specific habitat use patterns that will be useful in the development of management strategies for sawfishes and their habitats.

• 出版日期2013-6