Utilization of Benthic Invertebrates as Salinity Indicators
in South Florida Rivers,
Lessons from the Peace and Alafia Rivers
Jim Culter
Mote Marine Laboratory
November 2013
Caloosahatchee Science
Workshop
Objectives




Peace & Alafia River Projects, Large & Intensive
Determine benthic components that will have greatest utility
for a possible long-term monitoring program.
 Species, communities, habitats or strata.
Evaluate relationships between the distribution and
abundance of important benthic components and salinity.
Conclusions Transferrable to Caloosahatchee River?
When
Peace River
 November 1998
 January 1999
 March 1999
 April 1999
 June 1999
Alafia River
 May 1999
 September 2001
end of wet season,
winter dry season,
spring dry season,
spring very dry season
end of dry season.
very low flow
end normal wet season
Level of Effort
 Peace

River – “Healthy River”
Mollusk survey – 61 sites, 2 visits
• 17,000 specimens

Infauna – 12 defined areas, 1,450 samples
•
•
•
•
•
•
4 zones intertidal / subtidal + 3 creeks + 1 SAV site
5 visits – 1 wet season, 4 dry season
Each area – 10 cores, 10 sweep nets, 1AS/km
+ 120 sediment samples for granulometry
60,936 benthic specimens
314 species
Level of Effort
 Alafia


River – “Impaired River”
Molluscs – 37 sites, 2 visits, 20 species
Infauna – 17 defined areas, 298 samples
•
•
•
•
•
•
2 Hillsborough Bay locations, 15 River locations
2 visits – 1 wet season, 1 dry season
Each area – 7 grabs & 2 sweep nets per season
120 sediment samples for granulometry
16,266 benthic specimens
222 species dry season, 132 species wet season
Level of Effort – 1994-1995
 Caloosahatchee



River – “Impaired River”
Infauna – 4 locations, 12 sample periods
192 samples
219 species identified from 26,269 organisms
Biologically Relevant Salinity Zones (NOAA)
used for strata for Peace River study
 Zone
I
 Zone II
 Zone III
 Zone IV
≤ 0.5 PSU freshwater
> 0.5 to ≤ 8.0
> 8.0 to ≤ 16.0
> 16.0 PSU estuarine
Peace River Zone Characteristics
Alafia River
60
40
20
10
27.88
Total Taxa - Dry Season
27.86
27.84
-82.44
-82.42
-82.40
-82.38
-82.36
-82.34
-82.32
-82.30
-82.28
60
40
20
10
27.88
Total Taxa - Wet Season
27.86
27.84
-82.44
-82.42
-82.40
-82.38
-82.36
-82.34
-82.32
-82.30
-82.28
Alafia River
Millions
27.88
7000
3000
1000
100
Total Amphipods per River km - Dry Season
27.86
27.84
-82.44
-82.42
-82.40
-82.38
-82.36
-82.34
-82.32
-82.30
-82.28
Millions
27.88
7000
3000
1000
100
Total Amphipods per River km - Wet Season
27.86
27.84
-82.44
-82.42
-82.40
-82.38
-82.36
-82.34
-82.32
-82.30
-82.28
Alafia River
Millions
27.88
600
300
100
10
Total Mysids per River km - Dry Season
27.86
27.84
-82.44
-82.42
-82.40
-82.38
-82.36
-82.34
-82.32
-82.30
-82.28
Millions
27.88
600
300
100
10
Total Mysids per River km - Wet Season
27.86
27.84
-82.44
-82.42
-82.40
-82.38
-82.36
-82.34
-82.32
-82.30
-82.28
0
Common
20
40
Rank of Abundance
Alafia River Taxa
ranked by
abundance vs.
weighted center
of salinity.
60
80
100
120
Rare
140
0
5
10
15
Salinity
20
25
Alafia River Alafia River
Area
downstream to
upstream.
River Area (ha) at -0.12m Elevation NGVD
6
5
4
3
2
1
0
0
1
2
3
4
5
6
7
8
9 10 11 12 13 14 15 16 17
River Kilometer
Caloosahatchee
River Substrate
Dial Cordy and Associates,
Inc. 2012
Observations
fauna – species rich & abundant
 Life history details for most species sparse
 Epifaunal transients very important to fisheries
 Seasonal movement upstream important
 Benthic
Observations, continued.
 Intertidal
river habitat is important
 Rare taxa important? But not useful…
 Abundant taxa too plastic?
 High spatial and sample variance

Large sample numbers needed to detect differences
 Molluscs


(other than oysters)
Point in time collection ≠ species spatial domain.
70% more species in Peace than Alafia*.
Observations, continued.
 Molluscs
(other than oysters)
 Point in time collection ≠ species domain
*
 70% more species in Peace than Alafia
 Crustaceans – mobile species “keystone”
 Sedentary species worms etc. record of recent
past conditions
 It’s Complicated – few simple effective tools
End