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Environmental influences on the spatial ecology of juvenile smalltooth sawfish (Pristis pectinata): results from acoustic monitoring.

Simpfendorfer CA, Yeiser BG, Wiley TR, Poulakis GR, Stevens PW, Heupel MR - PLoS ONE (2011)

Bottom Line: The distance between 30-minute centers of activity was typically <0.1 km, suggesting limited movement over short time scales.Salinity electivity analysis demonstrated an affinity for salinities between 18 and at least 24 psu, suggesting movements are likely made in part, to remain within this range.Thus, freshwater flow from Lake Okeechobee (and its effect on salinity) affects the location of individuals within the estuary, although it remains unclear whether or not these movements are threatening recovery.

View Article: PubMed Central - PubMed

Affiliation: Center for Shark Research, Mote Marine Laboratory, Sarasota, Florida, United States of America. colin.simpfendorfer@jcu.edu.au

ABSTRACT
To aid recovery efforts of smalltooth sawfish (Pristis pectinata) populations in U.S. waters a research project was developed to assess how changes in environmental conditions within estuarine areas affected the presence, movements, and activity space of this endangered species. Forty juvenile P. pectinata were fitted with acoustic tags and monitored within the lower 27 km of the Caloosahatchee River estuary, Florida, between 2005 and 2007. Sawfish were monitored within the study site from 1 to 473 days, and the number of consecutive days present ranged from 1 to 125. Residency index values for individuals varied considerably, with annual means highest in 2005 (0.95) and lowest in 2007 (0.73) when several P. pectinata moved upriver beyond detection range during drier conditions. Mean daily activity space was 1.42 km of river distance. The distance between 30-minute centers of activity was typically <0.1 km, suggesting limited movement over short time scales. Salinity electivity analysis demonstrated an affinity for salinities between 18 and at least 24 psu, suggesting movements are likely made in part, to remain within this range. Thus, freshwater flow from Lake Okeechobee (and its effect on salinity) affects the location of individuals within the estuary, although it remains unclear whether or not these movements are threatening recovery.

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Environmental conditions within the study area.2005 was a wet year with high freshwater flows through the Franklin Locks (grey shaded area) of long periods with salinity at Cape Coral (black line) below 10 psu. 2006 was a moderately wet year with a short period of high flow, and 2007 was a dry year with very small flows and high salinity.
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pone-0016918-g002: Environmental conditions within the study area.2005 was a wet year with high freshwater flows through the Franklin Locks (grey shaded area) of long periods with salinity at Cape Coral (black line) below 10 psu. 2006 was a moderately wet year with a short period of high flow, and 2007 was a dry year with very small flows and high salinity.

Mentions: This study was conducted in the lower 27 km estuarine portion of the Caloosahatchee River in southwest Florida (Figure 1). The river connects Lake Okeechobee to the Gulf of Mexico and is the major source of freshwater to southern Charlotte Harbor. Water from Lake Okeechobee also flows to the east coast via the St Lucie River, and changes in the distribution between the two systems over time has affected the levels of freshwater flow. Freshwater flows in the Calooshatchee River during the current study were greatest during summer (Figure 2) and varied considerably between years depending on the magnitude of the wet season. The river has been substantially altered in the last 100 years [23], including an artificial link to Lake Okeechobee, extensive canal systems, three locks to permit boat passage, and dams to regulate water flow. The upper reaches of the study site had natural shoreline and native vegetation (primarily red mangroves Rhizophora mangle) while closer to the mouth the habitat was largely altered by urbanization including extensive canal developments and shoreline modification associated with the cities of Cape Coral and Fort Myers.


Environmental influences on the spatial ecology of juvenile smalltooth sawfish (Pristis pectinata): results from acoustic monitoring.

Simpfendorfer CA, Yeiser BG, Wiley TR, Poulakis GR, Stevens PW, Heupel MR - PLoS ONE (2011)

Environmental conditions within the study area.2005 was a wet year with high freshwater flows through the Franklin Locks (grey shaded area) of long periods with salinity at Cape Coral (black line) below 10 psu. 2006 was a moderately wet year with a short period of high flow, and 2007 was a dry year with very small flows and high salinity.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3037940&req=5

pone-0016918-g002: Environmental conditions within the study area.2005 was a wet year with high freshwater flows through the Franklin Locks (grey shaded area) of long periods with salinity at Cape Coral (black line) below 10 psu. 2006 was a moderately wet year with a short period of high flow, and 2007 was a dry year with very small flows and high salinity.
Mentions: This study was conducted in the lower 27 km estuarine portion of the Caloosahatchee River in southwest Florida (Figure 1). The river connects Lake Okeechobee to the Gulf of Mexico and is the major source of freshwater to southern Charlotte Harbor. Water from Lake Okeechobee also flows to the east coast via the St Lucie River, and changes in the distribution between the two systems over time has affected the levels of freshwater flow. Freshwater flows in the Calooshatchee River during the current study were greatest during summer (Figure 2) and varied considerably between years depending on the magnitude of the wet season. The river has been substantially altered in the last 100 years [23], including an artificial link to Lake Okeechobee, extensive canal systems, three locks to permit boat passage, and dams to regulate water flow. The upper reaches of the study site had natural shoreline and native vegetation (primarily red mangroves Rhizophora mangle) while closer to the mouth the habitat was largely altered by urbanization including extensive canal developments and shoreline modification associated with the cities of Cape Coral and Fort Myers.

Bottom Line: The distance between 30-minute centers of activity was typically <0.1 km, suggesting limited movement over short time scales.Salinity electivity analysis demonstrated an affinity for salinities between 18 and at least 24 psu, suggesting movements are likely made in part, to remain within this range.Thus, freshwater flow from Lake Okeechobee (and its effect on salinity) affects the location of individuals within the estuary, although it remains unclear whether or not these movements are threatening recovery.

View Article: PubMed Central - PubMed

Affiliation: Center for Shark Research, Mote Marine Laboratory, Sarasota, Florida, United States of America. colin.simpfendorfer@jcu.edu.au

ABSTRACT
To aid recovery efforts of smalltooth sawfish (Pristis pectinata) populations in U.S. waters a research project was developed to assess how changes in environmental conditions within estuarine areas affected the presence, movements, and activity space of this endangered species. Forty juvenile P. pectinata were fitted with acoustic tags and monitored within the lower 27 km of the Caloosahatchee River estuary, Florida, between 2005 and 2007. Sawfish were monitored within the study site from 1 to 473 days, and the number of consecutive days present ranged from 1 to 125. Residency index values for individuals varied considerably, with annual means highest in 2005 (0.95) and lowest in 2007 (0.73) when several P. pectinata moved upriver beyond detection range during drier conditions. Mean daily activity space was 1.42 km of river distance. The distance between 30-minute centers of activity was typically <0.1 km, suggesting limited movement over short time scales. Salinity electivity analysis demonstrated an affinity for salinities between 18 and at least 24 psu, suggesting movements are likely made in part, to remain within this range. Thus, freshwater flow from Lake Okeechobee (and its effect on salinity) affects the location of individuals within the estuary, although it remains unclear whether or not these movements are threatening recovery.

Show MeSH
Related in: MedlinePlus