The authors have declared that no competing interests exist.
Conceived and designed the experiments: KLD LAM. Performed the experiments: KLD. Analyzed the data: KLD. Contributed reagents/materials/analysis tools: KLD LAM. Wrote the paper: KLD LAM.
Roads, bridges, and dikes constructed across salt marshes can restrict tidal flow, degrade habitat quality for nekton, and facilitate invasion by non-native plants including
It is well established that fish and swimming crustaceans (termed “nekton”) use vegetated intertidal salt marsh habitats for refuge, feeding, as nurseries, and for reproduction
Throughout the United States, >50% of tidal salt marshes have decreased in size and quality
Introduced
Previous studies in New England have used measures of faunal presence/absence, quantity, richness, and diversity to assess habitat quality in tidally restricted marshes invaded by
Several studies have acknowledged the need to move beyond the collection of community data (e.g., density, richness) to assess the functional response of nekton to tidal restrictions and restoration
Morphological and physiological indicators have been used to examine habitat quality for fish residing in different environments
Our study builds on earlier work by directly linking habitat quality to measurable attributes of fish health and productivity. We examined the influence of habitat quality on fish condition and growth using the above morphological and physiological indicators in order to address the following research questions: 1) Does the condition and growth of fish residing in tidally restricted marshes invaded by
Our study was carried out in strict accordance with the American Veterinary Medical Association Guidelines on Euthanasia and was approved by the University of Rhode Island Institutional Animal Care and Use Committee (protocol #AN09-05-020). Permission for collections were given by the Connecticut Department of Environmental Protection (#SC-10021), Rhode Island Department of Environmental Management (#2010-39), Massachusetts Division of Marine Fisheries (#159948), National Park Service Cape Cod National Seashore (#CACO-2010-SCI-0016), Rachel Carson National Wildlife Refuge (#53553-2009-05, 2010-05, 2011-10), and Maine Department of Marine Resources (#2009-53-00, 2010-60-01, 2011-45-02).
We selected four tidally restricted (hereafter, “restricted”) and four tidally restored (“restored”) salt marshes invaded by introduced
Hydrologic Status/Marsh Type | Site | Latitude/Longitude | Region | System Type | Purpose ofRestriction | YearRestricted | YearRestored | Marsh Size(ha) | Tidal Range(m) | Salinity (ppt) |
Restored | Barn Island (IP3),Stonington, CT | 41°20′22′′N, 71°52′29′′W | LIS | marsh meadow | waterfowl/hunting | 1947 | 1991 | 11 | 0.87 | 23.42 |
Restored | Drakes Island, Wells, ME | 43°19′49′′N, 70°33′30′′W | GOM | marsh meadow | agriculture | 1848 | 1988/2005 |
35 | 0.86 | 29.54 |
Restored | Galilee, Galilee, RI | 41°22′42′′N, 71°30′08′′W | LIS | marsh meadow | travel/commerce | 1956 | 1997 | 40 | 0.47 | 30.84 |
Restored | Hatches Harbor,Provincetown, MA | 42°03′56′′N, 70°14′09′′W | GOM | marsh meadow | mosquito/flood control | 1930 | 1999 | 40 | 0.55 | 31.69 |
Reference ( |
Barn Island (IP3),Stonington, CT | 41°20′22′′N, 71°52′29′′W | LIS | marsh meadow | n/a | n/a | n/a | 28 | 0.82 | 26.58 |
Reference ( |
Drakes Island,Wells, ME | 43°19′49′′N, 70°33′30′′W | GOM | marsh meadow | n/a | n/a | n/a | 28 | 2.12 | 31.47 |
Reference ( |
Galilee, Galilee, RI | 41°22′42′′N, 71°30′08′′W | LIS | fringing marsh | n/a | n/a | n/a | 11 | 0.59 | 30.73 |
Reference ( |
Hatches Harbor,Provincetown, MA | 42°03′56′′N, 70°14′09′′W | GOM | marsh meadow | n/a | n/a | n/a | 34 | 0.65 | 31.70 |
Restricted | Herring River,Wellfleet, MA | 41°55′54′′N, 70°03′49′′W | GOM | tidal riverine | travel/commerce | 1908 | n/a | 42 |
0.50 | 17.08 |
Restricted | Sluice Creek,Guilford, CT | 41°16′32′′N, 72°39′52′′W | LIS | tidal riverine | agriculture | 1847 | n/a | 31 | 0.70 | 16.40 |
Restricted | Stony Brook,Brewster, MA | 41°45′05′′N, 70°06′49′′W | GOM | tidal riverine | agriculture/salt works | 1700′s | 2011 |
8 | 0.60 | 11.13 |
Restricted | Sybil Creek,Branford, CT | 41°15′43′′N, 72°47′59′′W | LIS | tidal riverine | flood control | early 1900′s | n/a | 30 | 0.36 | 20.73 |
Reference ( |
Herring River,Wellfleet, MA | 41°55′54′′N, 70°03′49′′W | GOM | fringing marsh | n/a | n/a | n/a | 40 | 2.30 | 28.89 |
Reference ( |
Sluice Creek,Guilford, CT | 41°16′32′′N, 72°39′52′′W | LIS | marsh meadow | n/a | n/a | n/a | 29 | 1.70 | 22.36 |
Reference ( |
Stony Brook,Brewster, MA | 41°45′05′′N, 70°06′49′′W | GOM | marsh meadow | n/a | n/a | n/a | 36 | 1.40 | 30.80 |
Reference ( |
Sybil Creek,Branford, CT | 41°15′43′′N, 72°47′59′′W | LIS | marsh meadow | n/a | n/a | n/a | 14 | 1.80 | 22.14 |
Citations: [23,25,35,63–76; Dr. Michele Dionne, Wells NERR, unpublished data].
Drakes Island (restored): Unplanned partial restoration in 1988 (flapper gate fell off during storm); self-regulating tide gate installed in 2005.
Herring River (restricted): Total suitable habitat area for my study (upstream of Chequessett Marsh Rd., downstream of High Toss Rd); total area for potential restoration- 445 ha.
Stony Brook (restricted): Two failing culverts were replaced between year 1 and year 2 of my study (winter 2010–2011).
Site characteristics are reviewed in
We collected data on water column salinity (ppt), temperature (°C), and dissolved oxygen (mg/L) at each station using a YSI-85 (2010) and a YSI Pro-2030 (2011). Water quality data were spot measurements (n = 1 per station per time period) taken from approximately mid-way through flood tide to peak high tide (prior to ebbing) when fish were removed from the water column. We collected water quality data from all sites in fall 2010, summer 2011, and fall 2011, but only from the four southern sites in Connecticut and Rhode Island in summer 2010 (due to equipment malfunction). Sampling dates were as follows: summer 2010 (7/12–7/25, 7/29), fall 2010 (9/22–10/3), summer 2011 (7/11–7/23), and fall 2011 (9/25–10/7). Study sites were sampled along a south-to-north transect in summer, and then along a north-to-south transect in fall to account for seasonality changes in the marshes. For gravidity data, sites were sampled during one lunar cycle in summer 2010 (new moon on 7/11/10, full moon on 7/26/10), while sites were sampled during the days leading up to and just past full moon (7/15/11) in summer 2011.
On flood tide at each station on every sample date we deployed two minnow traps containing bait in enclosed mesh packets (to prevent consumption). All traps were placed within one meter of the salt marsh bank parallel to the shore in the main tidal creek of each system
In 2010 and 2011 we extracted whole-body lipid reserves from 1,920 adult fish (n = 960 fish/year). Powdered fish samples were packed into pre-weighed Whatman cellulose extraction thimbles, dried to a constant weight in a 50°C oven overnight, re-weighed pre-extraction, extracted for six hours using petroleum ether and a Soxhlet apparatus, dried in a 50°C oven overnight, and then re-weighed post-extraction
Radtke and Dean
To verify the relationship between otolith growth and somatic growth
During field collections, we recorded the fork length and wet weight of 1,487 fish in 2010 and 1,529 fish in 2011. We use a common morphometric index of fish condition, Fulton’s Condition Factor (K), to compare the condition of adult fish. It is calculated using the following equation:
In total, our main experiment included two paired marsh comparisons (restricted vs. reference; restored vs. reference). Each of the 48 Experimental Units (EU) were visited twice in 2010 (n = 96) and twice in 2011 (n = 96). Because we collected samples from each EU over time, we analyzed data using repeated measures mixed model ANOVA (Statistical Package SAS, v 9.2). To avoid pseudoreplication we took the mean of each response variable collected on each EU on each sampling date (i.e., the mean of 10 fish for proximate body composition, 5 for recent daily growth, 16 for morphology). The exception to this was water quality data, for which we had one data point per EU on each sample date (except the four sites in summer 2010, as discussed above). We used SLICES in the model to examine interaction effects to determine whether there were significant differences in the response after explanatory variables were incorporated into the model (i.e., marsh type, time, region, parasitism status, gravidity, sex). We used Heterogeneous Autoregressive (1) as our covariance structure because it assumes that data that are farther apart in time will be less similar and that each time period has its own unique variance. Assumptions of normality and equality of variances within datasets were verified prior to all statistical analyses. We arcsine-square-root transformed our percent lipid, lean dry, and water data prior to analysis. For proximate body composition and growth rate data we incorporated mean fish length into the model as a covariate to ensure significant differences were attributable to marsh type and not differences in fish size
Proportions of gravid and/or parasitized fish were compared between habitats using Two Sample Tests for Proportions; data is reported as the mean ± proportional standard deviation. A continuity correction was conducted for the restricted vs. reference gravidity data to increase the quality of the normal approximation to the binomial distribution. To determine whether it was necessary to remove afflicted individuals from the analysis, we quantified the effects of parasitism and gravidity on fish lipid mass and morphology using repeated measures ANOVA. Due to unequal sample size (>2×), we analyzed the effects of parasitism/gravidity on recent daily growth using Welch’s t-tests. We used Simple Linear Regression to model the relationship between fish length and otolith radius in healthy fish (i.e., those without ecto/endoparasites or eggs present) and examined homogeneity of fish age class distributions using Chi Square Tests of Homogeneity. Lipid and lean dry mass results are presented as a percentage of fish dry weight, water mass as a percent of wet weight, growth as the mean recent daily growth increment of the otolith (in micrometers), and morphology as a unitless index value (K). Means are reported for each statistic ± standard deviation.
We collected 164 sets of water quality data from the 48 stations from 2010–2011 (
Response | Salinity (ppt) | Temperature (°C) | Dissolved Oxygen (mg/L) | N |
Restored | 28.62 (6.79) | 21.44 (3.62) | 6.98 (2.78) | 42 |
Reference ( |
29.89 (3.65) | 20.41 (3.25) | 7.15 (2.34) | 41 |
Restricted | 14.19 (9.65) | 21.98 (3.92) | 7.50 (2.44) | 39 |
Reference ( |
25.50 (4.78) | 21.17 (3.86) | 6.44 (2.55) | 42 |
Data is presented as the mean proportion ± standard deviation.
Ectoparasites | Endoparasites | Total | |
Restored | |||
Abundance | 68 | 29 | 97 |
Total Infected | 56 | 18 | 72 |
Infection Intensity | 1.21 | 1.61 | 1.35 |
Prevalence | 7.46% | 2.40% | 9.59% |
Weighted Prevalence | 9.05% | 3.86% | 12.92% |
Reference ( |
|||
Abundance | 62 | 42 | 104 |
Total Infected | 53 | 13 | 62 |
Infection Intensity | 1.17 | 3.23 | 1.68 |
Prevalence | 7.02% | 1.72% | 8.21% |
Weighted Prevalence | 8.21% | 5.56% | 13.77% |
Restricted | |||
Abundance | 91 | 396 | 487 |
Total Infected | 77 | 132 | 185 |
Infection Intensity | 1.18 | 3.00 | 2.63 |
Prevalence | 10.19% | 17.46% | 24.47% |
Weighted Prevalence | 12.04% | 52.38% | 64.42% |
Reference ( |
|||
Abundance | 83 | 195 | 278 |
Total Infected | 69 | 70 | 125 |
Infection Intensity | 1.20 | 2.79 | 2.22 |
Prevalence | 9.15% | 9.28% | 16.58% |
Weighted Prevalence | 11.01% | 25.86% | 36.87% |
We successfully extracted whole body lipids from 1,915 of 1,920 fish captured from 2010–2011. Approximately 14.67% (n = 281) of the fish analyzed for proximate body composition were parasitized. Incorporation of parasitism status into a repeated measures ANOVA revealed a significant negative effect on lipid stores when fish length was added as a covariate (p = 0.0181; F1,37 = 6.12), with lower lipid reserves in parasitized fish (
Using pooled data by sex across habitat/time periods, we found that fish in the Gulf of Maine had significantly more lipid than those in Long Island Sound (p<0.0001; F1,40 = 125.70), which was consistent by season and suggests influences of countergradient variation
Healthy fish only- data pooled across seasons, regions, and sex. Outlier circles represent the 5th and 95th percentiles and error bars the 10th and 90th percentiles for each population. (A) % lipid mass (dry weight). (B) % lean mass (dry weight). (C) % water mass (wet weight).
Response | Lipid(% of dry) | Total lipid(g) | Lean mass(% of dry) | Total leanmass (g) | Water(% of wet) | Totalwater (g) | Fish length(mm) |
Restored | 8.78 (2.69) | 0.08 (0.05) | 91.22 (2.69) | 0.84 (0.38) | 80.14 (1.66) | 3.62 (1.50) | 69.7 (9.5) |
Reference ( |
9.09 (2.63) | 0.06 (0.04) | 90.91 (2.63) | 0.63 (0.32) | 80.56 (1.62) | 2.81 (1.38) | 63.6 (9.4) |
Restricted | 7.48 (2.61) | 0.06 (0.04) | 92.52 (2.61) | 0.75 (0.32) | 80.54 (1.42) | 3.26 (1.29) | 67.0 (8.7) |
Reference ( |
8.62 (2.49) | 0.10 (0.07) | 91.38 (2.49) | 0.96 (0.46) | 80.04 (1.75) | 4.59 (5.21) | 71.6 (10.0) |
Gulf of Maine | 9.90 (2.20) | 0.10 (0.06) | 90.10 (2.20) | 0.92 (0.44) | 80.20 (1.58) | 4.23 (3.89) | 71.2 (10.4) |
Long Island Sound | 7.08 (2.33) | 0.05 (0.02) | 92.92 (2.33) | 0.67 (0.29) | 80.44 (1.67) | 2.90 (1.13) | 64.7 (8.0) |
Summer 2010 | 7.51 (2.22) | 0.06 (0.04) | 92.49 (2.22) | 0.76 (0.28) | 81.71 (1.54) | 3.63 (1.25) | 69.9 (7.1) |
Fall 2010 | 8.41 (2.50) | 0.08 (0.06) | 91.59 (2.50) | 0.85 (0.44) | 80.05 (1.51) | 3.60 (1.69) | 69.7 (10.7) |
Summer 2011 | 7.72 (2.25) | 0.07 (0.05) | 92.28 (2.25) | 0.86 (0.41) | 80.30 (1.10) | 3.72 (1.67) | 69.0 (9.4) |
Fall 2011 | 10.31 (2.74) | 0.08 (0.06) | 89.69 (2.74) | 0.71 (0.41) | 79.24 (1.28) | 3.33 (5.24) | 63.3 (10.3) |
Males | 8.23 (2.87) | 0.07 (0.05) | 91.77 (2.87) | 0.75 (0.38) | 80.18 (1.76) | 3.24 (1.46) | 66.9 (9.5) |
Females | 8.75 (2.42) | 0.08 (0.05) | 91.25 (2.42) | 0.83 (0.41) | 80.46 (1.48) | 3.89 (3.86) | 69.0 (10.1) |
% Lipid | % Lean Dry Mass | % Water | |||||
Model Terms | Sign. | t-statistic | Sign. | t-statistic | Sign. | t-statistic | d.f. |
Marsh | p = 0.0013 | 3.45 | p = 0.0013 | −3.45 | p = 0.5213 | −0.65 | 40 |
Marsh × Region | |||||||
GOM | p = 0.0116 | 2.65 | p = 0.0116 | −2.65 | p = 0.3746 | −0.90 | 40 |
LIS | p = 0.0305 | 2.24 | p = 0.0305 | −2.24 | p = 0.9907 | −0.01 | 40 |
Marsh × Time | |||||||
Summer 2010 | p = 0.0519 | 1.96 | p = 0.0519 | −1.96 | p = 0.4474 | 0.76 | 120 |
Fall 2010 | p = 0.0112 | 2.58 | p = 0.0112 | −2.58 | p = 0.3111 | −1.02 | 120 |
Summer 2011 | p = 0.0141 | 2.49 | p = 0.0141 | −2.49 | p = 0.3092 | −1.02 | 120 |
Fall 2011 | p = 0.1970 | 1.30 | p = 0.1970 | −1.30 | p = 0.5632 | −0.58 | 120 |
Marsh × Sex | |||||||
Males | p = 0.0068 | 2.85 | p = 0.0068 | −2.85 | p = 0.1892 | −1.34 | 40 |
Females | p = 0.0027 | 3.20 | p = 0.0027 | −3.20 | p = 0.7592 | 0.31 | 40 |
Marsh × Region × Sex | |||||||
GOM, Males | p = 0.0096 | 2.72 | p = 0.0096 | −2.72 | p = 0.0400 | −2.12 | 40 |
GOM, Females | p = 0.0801 | 1.80 | p = 0.0801 | −1.80 | p = 0.4887 | 0.70 | 40 |
LIS, Males | p = 0.1964 | 1.31 | p = 0.1964 | −1.31 | p = 0.8144 | 0.24 | 40 |
LIS, Females | p = 0.0088 | 2.75 | p = 0.0088 | −2.75 | p = 0.7863 | −0.27 | 40 |
We analyzed lipid-free dry mass (composed primarily of protein and bone/ash) in healthy fish to examine investment in body structure vs. lipid storage. Because we analyzed data on a dry weight basis, % lipid and % lean dry mass are the only two proportions in dry fish weight. Therefore, the statistics reported (
Our capture and fish selection methodology was designed to gather information from a range of fish sizes present at each site, so we analyzed whether the proportion of age classes differed between marsh systems. We report age data from 465 fish in 2010 and 479 fish in 2011. From 2010–2011, we captured five age classes of fish (ages 0, 1, 2, 3, 4). Although it was not our intent to capture fish in the age 0 class (i.e., those in their first year of life), we captured 31 fish in fall 2011 that had grown to at least 40 mm and were therefore included in our field collections. Chi Square Tests of Homogeneity revealed a significant difference in age class distributions between restored vs. reference marsh systems (p = 0.0280; χ24 = 10.8785; n = 473;
Due to unclear daily growth rings or other structural abnormalities in the otoliths (e.g., irregular accretion of calcium carbonate along the edge, resulting in a scalloped morphology) we initially discarded 263 fish from our study, with an additional 155 discards due to a >10% difference between the first and second growth readings. In total we analyzed growth rate data from 542 fish from 2010–2011 (56.5%). Our approach is consistent with other studies that have selected only the clearest otoliths for microstructure analysis (top 15.7%)
An analysis of the effects of parasitism and gravidity did not reveal significant negative effects on fish growth rate (p = 0.7739; t94.26 = −0.288); however, we removed an additional 81 parasitized and/or gravid individuals from the growth rate analysis to be consistent in our interpretation of results across physiological and morphological analyses, resulting in growth rate data for 461 healthy fish. Using simple linear regression we found a highly significant relationship between fish length and otolith radius for healthy fish (p<0.0001; r2 = 0.6628; Otolith radius = −2.77341 + 0.09572* fish length;
(Otolith radius = −2.77341+0.09572*fish length; p<0.0001; r2 = 0.6628).
Using the healthy individuals in the population and fish length as a covariate, we found that females grow significantly faster than males (p = 0.0461; F1,38 = 4.25;
Response | Daily Growth(µm) | Otolith Radius(µm) | Otolith Length(µm) | Otolith Height(µm) | Fish Length(mm) | Fish Wet Weight(g) |
Restored | 2.16 (0.66) | 719.16 (102.21) | 1496.63 (207.74) | 1351.16 (157.28) | 66.2 (11.9) | 3.88 (2.20) |
Reference ( |
2.26 (0.74) | 669.96 (99.81) | 1393.41 (212.99) | 1271.54 (167.68) | 61.7 (11.5) | 3.09 (1.84) |
Restricted | 2.21 (0.79) | 692.70 (86.86) | 1450.01 (193.28) | 1324.26 (134.89) | 61.2 (11.1) | 2.98 (1.78) |
Reference ( |
2.26 (0.75) | 726.75 (107.94) | 1559.24 (227.14) | 1391.76 (158.14) | 67.8 (12.7) | 4.29 (2.79) |
Gulf of Maine | 2.20 (0.64) | 681.37 (99.97) | 1451.10 (229.76) | 1317.49 (172.15) | 67.0 (13.0) | 4.05 (2.59) |
Long Island Sound | 2.24 (0.81) | 721.39 (102.13) | 1495.87 (209.91) | 1348.28 (153.15) | 62.0 (10.7) | 3.18 (1.81) |
Summer 2010 | 3.03 (0.64) | 720.36 (92.25) | 1501.03 (188.93) | 1355.08 (134.94) | 67.7 (10.0) | 4.06 (1.96) |
Fall 2010 | 2.09 (0.37) | 719.18 (107.44) | 1520.13 (250.34) | 1362.19 (179.38) | 66.0 (13.5) | 3.91 (2.77) |
Summer 2011 | 2.39 (0.54) | 728.15 (103.99) | 1521.30 (209.17) | 1380.89 (153.29) | 67.6 (10.6) | 3.77 (1.85) |
Fall 2011 | 1.53 (0.19) | 655.91 (93.36) | 1384.16 (202.22) | 1261.84 (156.15) | 58.4 (11.3) | 2.84 (2.10) |
Males | 2.21 (0.71) | 691.85 (96.71) | 1461.51 (207.13) | 1330.16 (157.45) | 62.8 (10.8) | 3.23 (1.72) |
Females | 2.23 (0.75) | 712.53 (108.28) | 1487.33 (233.71) | 1336.65 (169.28) | 66.1 (13.1) | 3.99 (2.67) |
By marsh type, we did not detect differences in the growth rate between fish residing in restored vs. reference marshes (p = 0.2506; t40 = 1.17), nor between fish in the restricted vs. reference marshes (p = 0.5153; t40 = 0.66;
Analysis of morphology data using Fulton’s K in our repeated measures ANOVA revealed no overall negative effect of parasitism/gravidity on fish condition (p = 0.7453; F1,40 = 0.11). However, to be consistent in our interpretation of results across analyses we removed all afflicted individuals from the analysis (n = 517). Using only healthy fish (n = 2,499), we found no significant difference between the restored vs. reference (p = 0.6273; t40 = −0.49) or the restricted vs. reference marsh fish (p = 0.4962; t40 = 0.69). Analysis of possible interactions between marsh type, region, time, and sex revealed only one significant difference between the reference and restricted marsh fish in fall 2010 (p = 0.0458; t120 = 2.02), with Fulton’s K indicating that reference marsh fish were in better condition than those in restricted marshes. We did find a difference between the summer and fall seasons in 2010 (p = 0.0016; t120 = −3.22) and a marginal difference in 2011 (p = 0.0570; t120 = −1.92), but the effect was in the opposite direction, with Fulton’s K labeling summer fish (post-reproduction) healthier than those in fall (pre-hibernation) in both years. In addition, this morphological index did not detect trends in condition between sexes (p = 0.3804; F1,40 = 0.89) or regions (p = 0.7849; F1,40 = −0.27) found using physiological indices.
We analyzed length-weight relationships using Multiple Linear Regression (with categorical variables for the marsh types). Examination of fit statistics (AIC, AICC, BIC), output from the regression coefficient hypothesis tests, adjusted R2, and multicollinearity statistics (tolerance, variance inflation factor) revealed that quadratic models best explained the length-weight relationships for the restored, restricted, and reference marsh fish (
Data pooled across seasons, regions, and by gender. (A) Restored vs. reference fish. (B) Restricted vs. reference fish.
There was a strong positive linear relationship (p = 0.0058) as well as evidence of a curvilinear relationship (p<0.0001) between fish length and weight, with the intercept not significantly different from zero (p = 0.2329). For the restricted vs. reference marsh fish, one regression line again best explained both populations (adj. R2 = 0.9602; p<0.0001;
There was a strong positive linear relationship (p = 0.0009) and evidence of a curvilinear relationship (p<0.0001) between fish length and weight, with no difference in intercept (p = 0.0668). Combined with results using the Fulton’s K condition factor, results indicate that fish at our study sites are morphologically indistinguishable.
Our study demonstrates that fish residing in tidally restricted marshes invaded by
Access to the marsh surface is ultimately influenced by the frequency, depth, and duration of tidal flooding, with nekton exhibiting a positive relationship between marsh selection and flooding duration
Our data suggest that with reduced or limited access to the marsh surface,
A second potential reason for reduced lipid reserves relates to increased movement of fish due to predation risk and reduced habitat refugia at high tide. For
We found gravidity in
Restoring hydrologic flow to salt marshes to decrease the cover and height of introduced
Notably, fish using the reference
Over time, nekton patterns in the restored marshes can mimic those in reference areas as the hydrologic connection between habitats allows greater faunal and prey exchange
Tidally restricted salt marshes invaded by introduced
We thank Penelope Pooler for her assistance with and review of our analysis and results. We also thank Peter August and the University of Rhode Island Environmental Data Center for drafting the map of our study sites.