RECONSTITUTING THE ESTUARINE COMMUNITY OF MAINLAND NEARSHORE SOUTH-CENTRAL BISCAYNE BAY

Joan A. Browder, Katarzyna Kulpa, Ian Zink, Gladys Liehr, Joseph Serafy, Diego Lirman, Sarah Bellmund, Thomas Jackson

Presentation for GEER 2017, April 17-19, Coral Springs, FL This project is based on monitoring data from the open water area adjacent to the Biscayne Bay shoreline, where CERP-related changes in freshwater flow to the bay will be most strongly reflected in changes in salinity and epifauna affected by salinity.

CERP aims to restore a more natural inflow volume and distribution in space and time, potentially increasing the area, frequency and duration of mesohaline and low polyhaline salinity conditions. IBBEAM Integrated Biscayne Bay Ecological Monitoring and Assessment

Long-term Objective of Project to be described today:

Visualizing the target nearshore estuarine epifaunal community

Developing community performance measures and targets to help us get there and know when we’ve arrived. MONITORING AREA IBBEAM Epifaunal Monitoring

47 sites

2007 - 2016

DRY season

January-March

WET season

July-September • A 1-m² throw-trap, cleared with a sweep net (4 sweeps), was used to sample epifauna in a 3-m² area at each site. • Samples consisted of small fish, shrimp, crabs, and echinoderms. • Salinity and other environmental variables were measured at each site. • Fish were identified to or higher taxa, weighed, and measured. Approach

• Fish community dynamics in relation to salinity is the main focus of this presentation.

• We assign fish species to halohabitat types based on the median salinity of the distribution of their members.

• Then we compare halohabitat groups for how they change over time and differ between 5-yr periods. This overview of fish species in relation to salinity covers the 10-yr period 2007-2016 and two 5-yr periods within it: 2007-2011 and 2012-2016.

Our hypotheses:

1. The nearshore epifauna fish community can be assigned to four halohabitat types that change differently in response to change in salinity.

2. Change in the fish community can be documented quantitatively in a 5-yr period. Total Collecting Period 2007-2016 2007-2011 Collections 2012-2016 Collections

Box plot components Box-plots were prepared to display the salinity of • Median distribution of all individuals of each species • 25 and 75 percentiles collected over the selected • 5 and 95 percentiles period. • Outliers

Species were classified to halohabitat based on median salinity of their distribution. Precipitation 2007-2016 100

90

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60

50 inches 40

30

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10

0

DRY 07 DRY 08 DRY 09 DRY 10 DRY 11 DRY 12 DRY 13 DRY 14 DRY 15 DRY 16 DRY

WET 07 WET 08 WET 09 WET 10 WET 11 WET 12 WET 13 WET 14 WET 15 WET 16 WET

Calendar year 10 year Calendar 13 year Calendar Calendar year 07 year Calendar 08 year Calendar 09 year Calendar 11 year Calendar 12 year Calendar 14 year Calendar 15 year Calendar 16 year Calendar

Total water year 07 year water Total 08 year water Total 09 year water Total 10 year water Total 11 year water Total 12 year water Total 13 year water Total 14 year water Total 15 year water Total 16 year water Total Salinity per site, Dry 2007-2011 Salinity per site, Wet 2007-2011 0 2 4 6 8 101214161820222426283032343638404244 0 2 4 6 8 101214161820222426283032343638404244 1 1 2 2 3 3 4 4 5 5 6 6 7 7 8 8 9 9 10 10 11 11 12 12 13 13 14 14 15 15 16 16 17 17 18 18 19 19 20 20 21 21 22 22 23 23

24 24 Site 25 Site 25 26 26 27 27 28 28 29 29 30 30 31 31 32 32 33 33 34 34 35 35 36 36 37 37 38 38 39 39 40 40 41 41 42 42 43 43 44 44 45 45 46 46 47 47 DRY 2007 Dry 2008 DRY 2009 DRY 2010 DRY 2011 WET 2007 WET 2008 WET 2009 WET 2010 WET 2011

Salinity per site 2007-2016

07D 07W 08D 08W 09D 09W 10D 10W 11D 11W 12D 12W Collection 13D 13W 14D 14W 15D 15W 16D 16W Mesohaline Polyhaline Euhaline Hyperhaline 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 Salinity (ppt) Southern sennet Gulf Stream flounder Goby sp. Puffer sp. sp. Chub sp. Collection 2007-2011 Banded killifish Crested blenny Lined sole Redear sardine Silver jenny Marsh killifish Distribution: Sheepshead minnow Checkered puffer Lined seahorse Hardhead silverside Median Jewel cichlid Clown goby Spaghetti eel Longsnout seahorse 25 and 75 percentiles Goldspotted killifish Gulf pipefish Bigeye mojarra 5 and 95 percentiles Jack sp. Rainwater killifish Code goby Crested goby Outliers Hogchoker Gray snapper Mosquitofish Sailfin molly Atlantic needlefish Highfin blenny fish Halohabitats: Dusky pipefish Bluestriped grunt Porgies sp. Mesohaline 5-18 Gulf killifish Grunt sp. Gulf toadfish Polyhaline Low18-24 Killifish sp. Redfin needlefish Pugnose pipefish Sargassum pipefish Polyhaline High 24-30 Unidentified Mangrove rivulus Frillfin goby Mojarra sp. Euhaline Low 30-35 Dwarf seahorse Yellowfin mojarra Florida blenny Euhaline High 35-40 Fringed pipefish Striped Mullet Pinfish Seahorse sp. Hyperhaline >40 Mullet sp. Mesohaline Polyhaline Euhaline Hyperhaline Spotted whiff 5-18 18-30 30-40 <40

0 5 10 15 20 25 30 35 40 45 salinity 2007-2011 Crested goby Least puffer Great Barracuda Tripletail Mayan Cichlid Collection 2012-2016 Goby sp. Killifish sp. Spotted whiff Beloniformes sp. Sheepshead minnow Distribution: Clown goby Hardhead silverside Median Sailor's choice Rainwater killifish Bandtail puffer 25 and 75 percentiles Lined sole Mojarra sp. Code goby 5 and 95 percentiles Pipefish sp. Pupfish sp. Outliers Mosquitofish Goldspotted killifish Gulf toadfish Pearl Blenny Percoidei*0 Gray snapper Halohabitats: Darter Goby Chain Pipefish Mesohaline 5-18 Gulf pipefish Seahorse sp. Sheepshead Polyhaline Low18-24 Dwarf seahorse Needlefish sp. Polyhaline High 24-30 Pinfish Checkered puffer Euhaline Low 30-35 Florida blenny Silverside sp. Unidentified Euhaline High 35-40 Halfbeak sp. Mangrove Gambusia Sailfin molly Hyperhaline >40 Fringed pipefish Mesohaline Polyhaline Euhaline Hyperhaline 5-18 18-30 30-40 <40

0 5 10 15 20 25 30 35 40 45 salinity 2012-2016 Cumulative species, by halohabitat, 2007-2011 65 60 55 50 45 40 35 30 25

#species of 20 15 10 5 0 07D 07W 08D 08W 09D 09W 10D 10W 11D 11W Total Me PoL PoH EuL Cumulative species, by halohabitat, 2012-2016 65 60 55 50 45 40 35 30

# of species of # 25 20 15 10 5 0 12D 12W 13D 13W 14D 14W 15D 15W 16D 16W Total Me PoL PoH Species added after indicated initial year, by halohabitat type.

Initial and after 2007 Initial and after 2012 35 35

30 30

25 25

20 20

15 15

10 10

5 5

0 0 Initial Dry Wet Initial Dry Wet Me PoL PoH EuL Me PoL PoH Species added after indicated initial year, by season

Initial and after 2007 Initial and after 2012 25 25

20 20

15 15

10 10

5 5

0 0 Me PoL PoH EuL Me PoL PoH Initial Dry Wet Initial Dry Wet Percentage by halohabitat 2007-2011 Percentage by halohabitat 2012-2016 Me EuL 3% 0% EuL PoH Me PoL 24% 33% 14% 36%

PoH PoL 37% 53%

Percentage by halohabitat, 2007-2016

EuL Me 11% 8%

PoH PoL 39% 42% Crested goby Collection 2007-2016 Least puffer Great Barracuda Tripletail Mayan Cichlid Goby sp. Southern sennet • Median Gulf Stream flounder Bandtail puffer Puffer sp. Beloniformes sp. Sheepshead minnow Chub sp. Killifish sp. • 25 and 75 percentiles Banded killifish Crested blenny Lined sole Sailor's choice Redear sardine Silver jenny Marsh killifish • 5 and 95 percentiles Hardhead silverside Mojarra sp. Clown goby Lined seahorse Pipefish sp. Pupfish sp. • Outliers Mosquitofish Jewel cichlid Pearl Blenny Percoidei*0 Rainwater killifish Gray snapper Darter Goby Halohabitats Spaghetti eel Goldspotted killifish Longsnout seahorse Chain Pipefish Gulf pipefish Bigeye mojarra Jack sp. • Mesohaline 5-18 Code goby Checkered puffer Hogchoker Sheepshead Needlefish sp. Atlantic needlefish • Highfin blenny Polyhaline Low18-24 Sargassum fish Southern Puffer Spotted whiff Northern puffer Silverside sp. Dusky pipefish • Polyhaline High 24-30 Bluestriped grunt Gulf toadfish Dwarf seahorse Porgies sp. Seahorse sp. Halfbeak sp. Gulf killifish • Euhaline Low 30-35 Florida blenny Mangrove Gambusia Sailfin molly Grunt sp. Unidentified Redfin needlefish • Pugnose pipefish Euhaline High 35-40 Sargassum pipefish Mangrove rivulus Frillfin goby Yellowfin mojarra Pinfish Fringed pipefish • Hyperhaline >40 Striped Mullet Mesohaline Polyhaline Euhaline Hyperhaline Mullet sp. 5-18 18-30 30-40 <40

0 5 10 15 20 25 30 35 40 45 salinity 2007-2016 Cumulative number of species by halohabitat, 2007-2016 80 75 70 65 60 55 50 45

40 # of species of # 35 30 25 20 15 10 5 0

Total Me PoL PoH EuL Test of Hypotheses: Number of years to 80% of asymptote with nonlinear least squares equation for each halohabitat type based on 10 years of cumulative species presence data.

Results: Species richness reaches 80% of asymptote in less than 10 years for all halohabitat types except mesohaline, which may continue to increase beyond 10 years.

Meso ? PolyL Analysis: Curves with PolyH asymptotes were fitted to EuhL trajectories of cumulative Tot species added by collection 0 2 4 6 8 10 (year-season). Years to 80% asymptote Test of Hypotheses:

Result: No significant difference in distribution of species by halohabitat in 2012-2016 period compared to 2007- 2015 period.

2007-2011 vs. 2008-2016 species

25 20 15 10 5 2008-2016 0 2007-2011 Number of species species of Number Me PoL PoH EuL 2007-2011 2 25 24 8 2008-2016 6 20 15 2

n = 102; X2 =4.703; p > 0.1 Halohabitat Color Key Me PoL PoH EuL No fish

Classification consistent throughout: 7 Common Name Scientific Name 2007-2011 2007-2016 2012-2016 Clown goby Microgobius gulosus 353 556 203 Goldspotted killifish Floridichthys carpio 1768 3590 1822 Gulf pipefish scovelli 750 1352 602 Hardhead silverside Atherinomorus stipes 1038 6358 5320 Distribution Lined sole Achirus lineatus 7 14 7 Pipefish sp. Sygnathiidae 16 71 55 by halohabitat Sheepshead minnow Cyprinodon variegatus 69 133 64 type of fish Classification went from lower to higher salinity, contrary to halohabitat change: 2 Bandtail puffer spengleri 1 2 1 species Checkered puffer Sphoeroides testudineus 49 79 30 Classification went from higher to lower salinity, following halohabitat change: 13 common to Code goby Gobiosoma robustum 313 856 543 Crested goby Lophogobius cyprinoides 5 30 25 both 5-yr Dwarf seahorse Hippocampus zosterae 9 23 14 Florida blenny Chasmodes saburrae 1 7 6 periods Goby sp. Gobiidae 4 62 58 Gray snapper Lutjanus griseus 2 7 5 Killifish sp. Cyprinodontiformes 18 70 52 Mojarra sp. Gerridae sp. 37 595 558 Mosquitofish Gambusia affinis 3 37 34 Rainwater killifish Lucania parva 14949 26188 11239 Seahorse sp. Hippocampinae sp. 1 2 1 n = 26 Spotted whiff Citharichthys macrops 2 4 2 Unidentified 8 10 2 X2 =10.29 Classification did not change from 1st 5yr to 10yr: 4 Code goby Gobiosoma robustum 313 856 543 p = 0.0119 Fringed pipefish Anarchopterus criniger 10 12 2 Gulf toadfish Opsanus beta 345 433 88 Pinfish Lagodon rhomboidalis 75 84 9 Halohabitat Color Key Me PoL PoH EuL No fish Halohabitat Color Key Me PoL PoH EuL No fish

Species present only in 2007-2011 period: 33 Species present only in 2012-2016 period: 17 Common Name Scientific Name 2007-2011 2007-2016 2012-2016 Common Name Scientific Name 2007-2011 2007-2016 2012-2016 Atlantic needlefish Strongylura marina 1 1 Beloniformes sp. Beloniformes sp. 1 1 Banded killifish Fundulus diaphanus 2 2 Chain Pipefish Syngnathus louisianae 1 1 Bigeye mojarra Eucinostomus havana 113 113 Darter Goby Ctenogobius boleosoma 1 1 Bluestriped grunt Haemulon sciurus 2 2 Great Barracuda Sphyraena barracuda 3 3 Chub sp. Cyprinidae 1 1 Halfbeak sp. Hemiramphidae 1 1 Crested blenny Hypleurochilus geminatus 4 4 Least puffer Sphoeroides parvus 1 1 Dusky pipefish Syngnathus floridae 1 1 Mangrove Gambusia Gambusia rhizophorae 4 4 Frillfin goby Bathygobius soporator 4 4 Mayan Cichlid Cichlasoma urophthalmus 1 1 Grunt sp. Haemulidae 8 8 Needlefish sp. Needlefish sp. 17 17 Gulf killifish Fundulus grandis 1 1 Pearl Blenny Entomacrodus nigricans 1 1 Gulf Stream flounder Citharichthys arctifrons 1 1 Percoidei Percoidei 1 1 Highfin blenny Lupinoblennius nicholsi 1 1 Pupfish sp. Cyprinodontidae 196 196 Hogchoker Trinectes maculatus 2 2 Sailor's choice Haemulon parra 1 1 Jack sp. Carangidae 1 1 Sheepshead Archosargus probatocephalus 2 2 Jewel cichlid Hemichromis bimaculatus 1 1 Silverside sp. Atherinidae 120 120 Lined seahorse Hippocampus erectus 2 2 Southern Puffer Sphoeroides nephelus 1 1 Longsnout seahorse Hippocampus reidi 2 2 Tripletail Lobotes surinamensis 1 1 Mangrove rivulus Rivulus marmoratus 1 1 Marsh killifish Fundulus confluentus 5 5 Mullet sp. Mugilidae sp. 1 1 Northern puffer Sphoeroides maculatus 2 2 Porgies sp. Sparidae 1 1 Puffer sp. sp. 4 4 Pugnose pipefish Bryx dunckeri 3 3 Redear sardine Harengula humeralis 1 1 Redfin needlefish Strongylura notata 1 1 Distribution by Sargassum fish Histrio histrio 2 2 Sargassum pipefish Syngnathus pelagicus 4 4 Silver jenny Eucinostomus gula 9 9 halohabitat type of fish Southern sennet Sphyraena picudilla 4 4 st Spaghetti eel Moringua edwardsi 1 1 species unique to 1 Striped Mullet Mugil cephalus 15 15 Yellowfin mojarra Gerres cinereus 2 2 (left) and 2nd (right) 5-yr n1 = 33; n2 = 17 periods. X2 = 8.02 p = 0.036 Test of Hypotheses: NMDS plots and 2-way PERMANOVA results comparing 1) 1st and 2nd 5-yr period and 2) seasonal differences in fish community species abundances

Result: Permanova suggests species abundance differs significantly between between 1st and 2nd 5-yr period and season. PERMANOVA results: Season F = 4.91, p = 0.004; 5-yr Period F = 2.84, p = 0.045 Perspective: NMDS plot and 2-way PERMANOVA results comparing salinity at sampling sites by 1) 1st and 2nd 5-yr period and 2) season.

Result: Permanova did not find significant differences in site salinities, separated by season, between 5-yr periods. PERMANOVA results: Season F = 4.06, p = 0.039; 5-yr Period F = 1.51, p = 0.222 • More than 5 years of data are required to confidently assign species to halohabitat type based on the species’ median salinity; 10 years of data appear more reliable. • Saturation curves fit to cumulative species curves explained more than 90% of their variance and reached 80% of their asymptote in less than 10 years. • A contingency table test found no sig. diff. in distribution of species among halohabitat types in 2nd vs. 1st 5-yr periods. • Halohabitat type distributions differed significantly (↓ salinity) in the 26 spp. common to both 5-yr periods. • Halohabitat distributions differed between the 1st period unique spp. (n=33) and 2nd period unique spp. (n=17) (↓ salinity). • A 2-way PERMANOVA test found a significant difference in species abundances between both 5-yr periods and seasons. • A 2-way PERMANOVA test found a significant difference in site salinities between seasons but not between 5-yr periods. • Investigate species-specific contributions to community differences between 5-yr periods. • Further investigate community structure relative to environmental gradients (i.e., expand NMDS analyses). • Use other sources of information beyond present dataset to develop a comprehensive list of species that could potentially colonize a more consistent nearshore Biscayne Bay estuarine habitat. • Investigate food web structure of nearshore Biscayne Bay and how this structure is affected by differing halohabitats and associated spp. THANK YOU ! • The BBEAM Team Halohabitat Color Key Me PoL PoH EuL No fish

Common Name Scientific Name 2007-2011 2007-2016 2012-2016 Atlantic needlefish Strongylura marina 1 1 Banded killifish Fundulus diaphanus 2 2 Bandtail puffer Sphoeroides spengleri 1 2 1 Beloniformes sp. Beloniformes sp. 1 1 Bigeye mojarra Eucinostomus havana 113 113 Bluestriped grunt Haemulon sciurus 2 2 Chain Pipefish Syngnathus louisianae 1 1 Checkered puffer Sphoeroides testudineus 49 79 30 Chub sp. Cyprinidae 1 1 Clown goby Microgobius gulosus 353 556 203 Code goby Gobiosoma robustum 313 856 543 Crested blenny Hypleurochilus geminatus 4 4 Crested goby Lophogobius cyprinoides 5 30 25 Darter Goby Ctenogobius boleosoma 1 1 Dusky pipefish Syngnathus floridae 1 1 Dwarf seahorse Hippocampus zosterae 9 23 14 Florida blenny Chasmodes saburrae 1 7 6 Frillfin goby Bathygobius soporator 4 4 Fringed pipefish Anarchopterus criniger 10 12 2 Goby sp. Gobiidae 4 62 58 Goldspotted killifish Floridichthys carpio 1768 3590 1822 Gray snapper Lutjanus griseus 2 7 5 Great Barracuda Sphyraena barracuda 3 3 Grunt sp. Haemulidae 8 8 Gulf killifish Fundulus grandis 1 1 Halohabitat Color Key Me PoL PoH EuL No fish

Common Name Scientific Name 2007-2011 2007-2016 2012-2016 Gulf pipefish Syngnathus scovelli 750 1352 602 Gulf Stream flounder Citharichthys arctifrons 1 1 Gulf toadfish Opsanus beta 345 433 88 Halfbeak sp. Hemiramphidae 1 1 Hardhead silverside Atherinomorus stipes 1038 6358 5320 Highfin blenny Lupinoblennius nicholsi 1 1 Hogchoker Trinectes maculatus 2 2 Jack sp. Carangidae 1 1 Jewel cichlid Hemichromis bimaculatus 1 1 Killifish sp. Cyprinodontiformes 18 70 52 Least puffer Sphoeroides parvus 1 1 Lined seahorse Hippocampus erectus 2 2 Lined sole Achirus lineatus 7 14 7 Longsnout seahorse Hippocampus reidi 2 2 Mangrove Gambusia Gambusia rhizophorae 4 4 Mangrove rivulus Rivulus marmoratus 1 1 Marsh killifish Fundulus confluentus 5 5 Mayan Cichlid Cichlasoma urophthalmus 1 1 Mojarra sp. Gerridae sp. 37 595 558 Mosquitofish Gambusia affinis 3 37 34 Mullet sp. Mugilidae sp. 1 1 Needlefish sp. Needlefish sp. 17 17 Northern puffer Sphoeroides maculatus 2 2 Pearl Blenny Entomacrodus nigricans 1 1 Percoidei Percoidei 1 1 Halohabitat Color Key Me PoL PoH EuL No fish

Common Name Scientific Name 2007-2011 2007-2016 2012-2016 Pinfish Lagodon rhomboidalis 75 84 9 Pipefish sp. Sygnathiidae 16 71 55 Porgies sp. Sparidae 1 1 Puffer sp. Tetraodontidae sp. 4 4 Pugnose pipefish Bryx dunckeri 3 3 Pupfish sp. Cyprinodontidae 196 196 Rainwater killifish Lucania parva 14949 26188 11239 Redear sardine Harengula humeralis 1 1 Redfin needlefish Strongylura notata 1 1 Sailfin molly Poecilia latipinna 9 14 5 Sailor's choice Haemulon parra 1 1 Sargassum fish Histrio histrio 2 2 Sargassum pipefish Syngnathus pelagicus 4 4 Seahorse sp. Hippocampinae sp. 1 2 1 Sheepshead Archosargus probatocephalus 2 2 Sheepshead minnow Cyprinodon variegatus 69 133 64 Silver jenny Eucinostomus gula 9 9 Silverside sp. Atherinidae 120 120 Southern Puffer Sphoeroides nephelus 1 1 Southern sennet Sphyraena picudilla 4 4 Spaghetti eel Moringua edwardsi 1 1 Spotted whiff Citharichthys macrops 2 4 2 Striped Mullet Mugil cephalus 15 15 Tripletail Lobotes surinamensis 1 1 Unidentified 8 10 2 Yellowfin mojarra Gerres cinereus 2 2

• Site

• Latitude and longitude

• Time

• Date

• Salinity

• Temperature

• Dissolved oxygen (DO)

• Conductivity

• pH

• Water depth

• Sediment depth

• SAV species-specific and community % cover (10-0.25 m² quadrats) Salinity per site 2007-2011

07D

07W

08D

08W

09D

09W

Collection 10D

10W

11D

11W Mesohaline Polyhaline Euhaline Hyperhaline

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 Salinity (ppt) Salinity per site 2012-2016

12D

12W

13D

13W

14D

14W

Collection 15D

15W

16D

16W

Mesohaline Polyhaline Euhaline Hyperhaline

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 Salinity (ppt) Halohabitat Categories, with upper and lower salinity bounds:

Lower salinity Upper salinity Halohabitat boundary boundary Oligohaline 0.000 5.000 Mesohaline 5.001 18.000 Polyhaline Low 18.001 24.000 Polyhaline High 24.001 30.000 Euhaline Low 30.001 35.000 Euhaline High 35.001 40.000 Hyperhaline 40.001+ • Oligohaline 0-5 • Mesohaline 5-18 • Polyhaline 18-30 – Poly Low 18-24 – Poly High 25-30 • Euhaline 30-40 • Hyperhaline >40 HYPOTHESES 1. The favorable salinity range for a fish species in a study area is reflected in the distribution of individuals with respect to salinity.

2. The fish community changes over time in response to change in salinity.

3. Change in the fish community can be documented quantitatively in a 5-yr period.

Hypotheses Tests with Contingency Tables Nonlinear least-squares regression Test of Hypotheses 2 and 3: NMDS plot and PERMANOVA results comparing first (2007-2011) and second (2012-2016) fish community species abundances

Result: At p ≤ 0.10, Permanova suggests species abundance difference between the first (2007-2011) and second (2012- 2016) 5 years.

PERMANOVA test result: p = 0.062 NMDS plot and PERMANOVA results of comparison of dry and wet season fish species abundances over 10-year period, 2007-2016

Result: Difference between dry season and wet season species abundance distributions are significant at p ≤ 0.05.

PERMANOVA results: p = 0.004 This overview of fish species in relation to salinity covers the 10-yr period 2007-2016 and two 5-yr periods within it: 2007-2011 and 2012-2016.

Our hypotheses: 1. The favorable salinity range for a fish species in a study area is reflected in the distribution of individuals with respect to salinity.

2. The nearshore fish community can be assigned to four halohabitat types that change differently in response to change in salinity.

3. Change in the fish community can be documented quantitatively in a 5-yr period.