Hurricane Effects on Molluscan Death Assemblages and Their Facies

Home , Bailya, Cerithium litteratum, Cyrtopleura costata, Favartia cellulosa, Hemitoma octoradiata, Morum oniscus

HURRICANE EFFECTS ON MOLLUSCAN DEATH ASSEMBLAGES AND THEIR FACIES

ERIC J. WYSONG

(Under the Direction of Sally Walker)

ABSTRACT

Hurricanes are major agents in sediment transport, but modern coral reef studies indicate that limited transport occurs among molluscan death assemblages. Such studies were largely conducted in environments with partially restricted bays that may limit transport. In contrast, few studies have been conducted in open-coastal reef environments. Three open-coastal leeward reef sites were studied in San Salvador, Bahamas, four and eight months following Hurricane

Frances to determine the degree of out-of-habitat transport (habitat mixing) in molluscan skeletal assemblages. Results indicate that: (1) habitat mixing is the norm; (2) consequently, the taxonomic compositions of death assemblages do not vary greatly between substrates; but, (3) diversity metrics and frequency of fragmentation are better differentiators between substrates and temporal intervals following the hurricane. As a result of storms/hurricanes, these environments are constantly being mixed; therefore, interpretation of the ecological fidelity of molluscs within fossil patch reefs must proceed cautiously.

INDEX WORDS: Patch reef, Mollusc, Death assemblage, Hurricane, Spatial fidelity, Sediment transport

HURRICANE EFFECTS ON MOLLUSCAN DEATH ASSEMBLAGES AND THEIR FACIES

ERIC J. WYSONG

B.S., University of Cincinnati, 2004

A Thesis Submitted to the Graduate Faculty of The University of Georgia in Partial Fulfillment

of the Requirements for the Degree

MASTER OF SCIENCE

ATHENS, GEORGIA

2008

Eric J. Wysong

HURRICANE EFFECTS ON MOLLUSCAN DEATH ASSEMBLAGES AND THEIR FACIES

ERIC J. WYSONG

Major Professor: Sally Walker

Committee: Steven M. Holland L. Bruce Railsback

Electronic Version Approved:

Maureen Grasso Dean of the Graduate School The University of Georgia May 2008

ACKNOWLEDGEMENTS

I would like to thank my major advisor Sally Walker for the tremendous amount of time and support that she has put into this project. Her enthusiasm and excitement for geology in the field and classroom is second to none. I am greatly indebted to her for all that she has done for me in every aspect of my experience at the University of Georgia. Additionally, I would like to thank my committee members Steve Holland and Bruce Railsback for their continuous support.

I am tremendously grateful to have had the opportunity to learn from them through multiple field experiences, classes, and throughout this research project.

I would also like to thank Beatriz Stephens for her crucial guidance and assistance in administrative processes as well as for always lending a listening ear. Finally, data collection was facilitated by three exceptional field assistants who kindly sacrificed their time in the

Bahamas: Karla Hubbard, Lisa Gardiner, and Lauren Dale.

This work was funded by the generous support of the Wheeler-Watts Fund, the

Geological Society of America, the Levy Fund, and the Paleontological Society.

TABLE OF CONTENTS

Page

ACKNOWLEDGEMENTS...... iv

LIST OF TABLES...... vii

LIST OF FIGURES ...... viii

CHAPTER

1 Introduction...... 1

Purpose of Study ...... 1

Molluscan Skeletal Remains and Hurricane Studies...... 4

Hurricane Effects on Reefal Sediments...... 6

Spatial Fidelity of Molluscan Hardparts ...... 8

2 Methods...... 14

Geologic Setting...... 14

Hurricane Frances...... 15

Field Methods...... 16

Transect Substrate Descriptions ...... 18

Laboratory Methods ...... 20

Treatment of Molluscs in Relation to Spatial Fidelity ...... 21

Fragmented Ratios...... 21

Diversity Metrics...... 22

Statistical Analyses...... 23

3 Results...... 26

Dataset Composition ...... 26

Live:Dead Distributions by Time and Transect ...... 27

Contributions of Rare and Abundant Taxa...... 29

Out-of-Habitat Transport of Molluscan Skeletal Remains...... 32

Relative Contributions of Gastropods and Bivalves ...... 35

Patterns of Hermitting within the Dataset ...... 35

Patterns of Gastropod Fragmentation within the Dataset...... 36

Diversity Metrics...... 37

Ordination Techniques Compared...... 42

Cluster Analyses of Beach-to-Reef Transects...... 47

4 Discussion...... 51

Comparison of Transects...... 51

Comparison of Substrates...... 52

Post-Hurricane Temporal Differences in Death Assemblages...... 54

5 Conclusion ...... 57

REFERENCES ...... 59

APPENDICES ...... 64

A Detailed Site Notes ...... 65

B Molluscan Substrate Affinities ...... 69

C Percent of Molluscs by Substrate Preference...... 73

D Mollusc Counts ...... 75

LIST OF TABLES

Page

Table 1: Modern reef studies concerning spatial fidelity...... 13

Table 2: Length, number of sites, and depth range for each of the three transects...... 17

Table 3: Generalized descriptions of environment types...... 19

Table 4: Numbers of live molluscs and dead molluscs found by month and by transect...... 26

Table 5: Live-dead fidelity determined for all data combined, data for each individual reef sites,

and data for each substrate type ...... 28

Table 6: Abundances of individual taxa and their percent contributions to the entire dataset ...... 30

Table 7: Percent of molluscs collected with specific habitat preferences ...... 32

Table 8: Percent of gastropods shells found hermitted at time of collection...... 36

Table 9: Mean gastropod fragmented ratios and t-tests of January versus June...... 37

Table 10: Statistical comparisons of fragmented ratios between substrates types ...... 37

Table 11: Diversity metrics by transect and month ...... 39

Table 12: Statistical comparisons of mean diversity metrics between substrates using 95%

confidence intervals from Welch 2-sample t-tests ...... 41

Table 13: Pearson Correlations Coefficients and associated confidence intervals between MDS

and DCA axes for multivariate ordinations of abundant taxa only...... 46

vii

LIST OF FIGURES

Page

Figure 1: Map showing location of San Salvador within the Bahamas...... 3

Figure 2: Map showing the path of Hurricane Frances in relation to San Salvador...... 3

Figure 3: Figure showing expected orientation of strongest winds on Fernandez Bay associated

with Hurricane Frances ...... 4

Figure 4: Map showing orientation and substrate relationships for reef transects ...... 15

Figure 5: Depth profiles and substrate types for the three transects ...... 17

Figure 6: Sampling curves with colored points distinguishing samples collected from each of

four different substrate types...... 31

Figure 7: Plots displaying results from non-metric multidimensional scaling and detrended

correspondence analysis of dataset...... 44

Figure 8: AGNES style two-way cluster analysis based on relative abundances of taxa

representing >1% of the total dataset using Bray dissimilarity matrix created from

double-Wisconsin standardized dataset...... 50

viii

CHAPTER 1

INTRODUCTION

Purpose of Study

This study addresses the spatial fidelity of molluscan death assemblages within open- coastal backreef environments from beaches to patch reefs following a Category 3 hurricane

(Hurricane Frances, September 2005). Environments sampled consisted of beaches, hardgrounds, patch reefs, and sandy environments, which lie adjacent to one another within spatial scales of tens of meters and less. If disturbance or transport of biota and resulting death assemblage results from hurricane-force waves and surge, this begs the question of how long such disturbance may persist as recorded within sediments. To address whether spatial fidelity of skeletal death assemblages was consistent over time, sampling was conducted four and a half months after Hurricane Frances, and again nine and a half months after the hurricane.

If molluscs live, die, and their skeletal remains reside within the same habitat, their death assemblages could provide useful paleoenvironmental information such as spatial scale and extent of various substrate types as well as patchiness of habitats and communities. But, if hurricane disturbance mixes or redistributes skeletal spatial distributions, then paleoenvironmental reconstructions in hurricane-dominated regions must be analyzed with caution. Following the results of previous studies (Kidwell and Bosence, 1991; Miller et al.,

1992; Best and Kidwell, 2000), it might be expected that molluscan death assemblages, regardless of hurricane disturbance, will exhibit high spatial fidelity to their original habitats.

This study took place on the island of San Salvador, Bahamas, on the eastern edge of the

Bahamas Archipelago (Figure 1). When Hurricane Frances made landfall on San Salvador, the center of the storm passed roughly five kilometers south of Fernandez Bay (Figure 2). Most of the visible damage resulting from Hurricane Frances occurred on the north and east (windward) coasts of the island; damage to the west coast, the leeward side, was limited. As the large eye of

Hurricane Frances passed by San Salvador, wind patterns in Fernandez Bay would have been directed primarily south to southwest as the storm approached at its strongest, then west

(seaward) while the storm was directly south of the bay, and northwest to north as the storm traveled away with diminishing strength (Figure 3).

Fernandez Bay hosts three major reef sites, Telephone Pole, Snapshot and Lindsay Reef.

Both Telephone Pole and Snapshot Reef are oriented parallel to shore, while Lindsay Reef lies approximately perpendicular to shore. The orientation of Lindsay Reef would have baffled or trapped sediments moving southwest whereas the orientations of Snapshot and Telephone Pole

Reefs would have inhibited those moving west. It is my hypothesis that mixing will have occurred as a result of this hurricane and that assemblages consisting of mostly out-of-habitat molluscan skeletal remains may be commonplace in these nearshore, shallow environments with frequent tropical storms and hurricanes as was the case in the same area prior to, and after,

Hurricane Floyd (Gardiner, 2001). This apparent deviation from earlier cited findings of high spatial fidelity (Kidwell and Bosence, 1991; Miller et al., 1992; Best and Kidwell, 2000) is not contradictory in that this study focuses on small-scale environmental changes in an environment more susceptible to storm activity.

FIGURE 1A: Map showing location of San Salvador within the Bahamas

FIGURE 1B: Map showing location of study sites in Fernandez Bay in the southern half of the west coast of San Salvador

FIGURE 2: Map showing the path of Hurricane Frances in relation to San Salvador.

FIGURE 3: Figure showing expected orientation of strongest winds on Fernandez Bay associated with Hurricane Frances.

Molluscan Skeletal Remains and Hurricane Studies

Molluscs are the most diverse phylum in the marine realm (Bouchet et al., 2002) and consist of many species that are specific to distinct environmental parameters such as substrate type, or wave energy; some may even be found only in association with other live organisms

such as taxa that only live on live coral or gorgonians. Molluscan remains are often taphonomically robust and thus exhibit high preservation potential allowing them to be an important constituent of many post-Paleozoic fossil reef and shallow carbonate assemblages

(Kidwell, 2001).

While passing from the beach seaward towards patch reefs in the Bahamas, one traverses through several types of environments defined on the basis of substrate type, such as: hardgrounds, pocketed or smooth; sand, coarse or fine; or live reef. As each of these environments can support different types of molluscs, there exists the possibility that molluscan death assemblages could be recognized that denote each of these various environments; that these assemblages could be said to exhibit high spatial fidelity. In carbonate patch-reef environments, substrate types can be patchy and may occur in close proximity to one another.

Many of these environments are also frequently affected by hurricanes that are capable of moving large amounts of sediment (Hubbard, 1992; Scoffin, 1993).

Studies of the utility of molluscan death assemblages to resolve past communities and environments are usually restricted to temperate and subtropical localities which focus on soft- bottom habitats (e.g., Kidwell and Bosence, 1991; Kidwell and Flessa, 1995; Kidwell, 2001;

Kidwell, 2002). These studies have mostly concluded that the aforementioned habitats do exhibit high spatial fidelity. Studies in reef environments, although scarce, have also uncovered trends of high spatial fidelity (see Miller et al., 1992; Best and Kidwell, 2000).

Best and Kidwell (2000a) concluded that postmortem transport of bivalve shells was not a homogenizing factor in their study site and there was high spatial fidelity in five distinct environments (Best and Kidwell, 2000a). However, their study site was located outside the range of Caribbean hurricane tracks and most of their sites were protected by an outer band of

bedrock islands. Additionally, they mapped environments at kilometer-scales where most were depicted to be approximately five-kilometers wide. Kilometer-scale environmental changes may be near the limit of what can be resolved stratigraphically but my study meets a necessity of persistently pushing these limits by sampling environments at finer spatial scales.

In studying marine environments that lie within hurricane-affected regions, one could expect a greater potential for death assemblages to become mixed. Mixing can be compounded by the patchiness that can be typical of reef environments. Consequently, in areas where reefs lie only a few meters from sand, muddy areas, or smooth hardgrounds, death assemblages need not travel far to become mixed.

Hurricane Effects on Reefal Sediments

Hurricanes redistribute cobbles, skeletal material, and fine-grained sediment (Kobluk and

Lysenko, 1992; Scoffin, 1993). Damage and sediment transport resulting from hurricanes are controlled not only by the nature of the storm, but also by the geometry of the study site and its relationship to the storm track (Hubbard, 1992). The focus of most storm-effect studies has been on the large component of debris and skeletal material that is transported onshore during hurricanes (Ball et al., 1967; Collins et al., 1999; Gardiner, 2001). Volumes of sediment can be flushed offshore during large hurricane events and patterns of sediment transport and reef damage as a result of such storms are complicated and variable (Hubbard, 1992). From these studies, one could argue that large-scale sediment transport associated with hurricanes could have the potential to create appreciable out-of-habitat movement of molluscan skeletal remains in open-coastal, storm-dominated reef environments.

Various studies have approached the impact of transport by observing, weighing, or measuring the sediment and its biotic constituents determined to be transferred out of their original environment (e.g. Hoskin et al., 1986; Boss and Liddell, 1987; Perry, 1996; Hughes,

1999; Hubbard, 1992). Even when transport is directly observed, it may not be enough to mix death assemblages so extensively that they can no longer be recognized as discrete assemblages.

The transport of sediment may also be restricted within the same general sedimentary facies and therefore spatial fidelity of death assemblages to habitats or subenvironments is still maintained.

Sediment transport can also be induced by Coriolis driven geostrophic current flows directed nearly parallel to shore by the effect (e.g. Swift et al., 1986). The Coriolis-effect is strongest in higher latitudes and currents of short duration or slow velocity are also not as effected (Swift et al., 1986; Snedden and Swift, 1991). Other evidence suggests that inner- to middle-shelf deposits even in high latitudes do not show much preservation of geostrophic currents (Leckie and Krystinik, 1989). To the best of my knowledge, shallow subtidal carbonate environments and patch reefs have not been investigated with regard to these phenomena.

Hurricane winds and surges could provide powerful driving forces in sediment movement in these shallow environments.

Storm-generated disturbance influences patterns of modern and fossil skeletal accumulations and community structure by controlling topography. For example, a study in St.

Croix following Hurricane Hugo demonstrated that patterns of reef development and consequently, community structure were strongly influenced by the historical trend of hurricanes approaching from the south (Hubbard et al., 2005). At St. Croix, hurricane-influenced debris creates a topographically higher reef on the south side than on the north side of the island.

Hubbard et al. (2005) found more variable dead species compositions occurred on the southern

reefs than those in the north; they furthermore determined, using data from cores, that this condition has persisted throughout the Holocene (Hubbard et al. 2005).

A classic study on molluscan skeletal transport was done by Miller et al. (1992) in St.

Croix following Hurricane Hugo. Miller et al. (1992) found that molluscan death assemblages discretely clustered between five distinct reef environments based on their taxonomic composition. Their study was conducted within a protected bay over substrates largely consisting of seagrass beds that may baffle current flow and thus minimize skeletal transport.

Features such as enclosed bays and the ubiquity of sea grass would undoubtedly minimize shell transport.

Although in protected environments molluscan death assemblages may show spatial fidelity, few studies have examined molluscan skeletal transport in open-coastal reef settings that lack sea grass beds (i.e., Gardiner, 2001). Hardgrounds and areas with sand bodies not stabilized by seagrass beds may show substantially different trends as the effects of storm-generated currents will be uninhibited.

Spatial Fidelity of Molluscan Hardparts

The topic of how well death assemblages correlate with their associated living assemblages is nothing new to paleoecologists (Brett and Baird, 1986; Boss and Liddell, 1987;

Miller, 1988; Davies et al., 1989; Miller et al., 1992; Pandolfi and Minchin, 1995; Zuschin and

Hohenegger, 1998; Best and Kidwell, 2000a,b; Zuschin et al., 2000; Edinger et al., 2001;

Gardiner, 2001; Kidwell, 2002; Vin a-Herbon et al., 2002; Parsons-Hubbard, 2005; Ferguson and

Miller, 2007); their studies illuminate a topic of important consideration when determining how much ecological or environmental information can be gleaned from death or fossil assemblages.

There is no standard scale to define what represents high spatial fidelity versus what represents low spatial fidelity; this is apparently left to the judgment of the paleoecologist. In general, if distinct assemblages are found to correlate well with environments, that would show high spatial fidelity. If such assemblages do not correlate with the environment they are found in, then spatial fidelity does not exist at that scale. Although the majority of spatial fidelity research has been conducted in level-bottom shelf environments, there are several useful studies that have focused on reef environments (Table 1).

To address spatial fidelity, three different types of modern data are often used: taxonomic, taphonomic, and ecologic. With taxonomic data, researchers can use relative abundance data along with analytical manipulations to examine species patterns and then correlate those patterns to environmental patterns (e.g. Miller et al., 1992; Zuschin and

Hohenegger, 1998; Gardiner, 2001; Vin a-Herbon et al., 2002; Bouchet et al., 2002). For well- sampled modern environments, comparisons of living taxa with dead taxa (live-dead studies) are also used to determine if the death assemblage adequately represents the living community (e.g.

Zuschin et al., 2000; Pandolfi and Minchin, 1995; Edinger et al., 2001). Impedimentary to live- dead studies is a requirement of extensive sampling to adequately census the live community

(Kidwell and Bosence, 1991). Extensive sampling effort is necessary for evaluating the relationship between death assemblages and the communities they represent (Kidwell, 2002).

Researchers have also considered taphonomic signatures imparted on skeletal debris to compare consistency within environments and differences among environments (e.g. Brett and

Baird, 1986; Davies et al., 1989; Zuschin and Hohenegger, 1998; Best and Kidwell, 2000a,b;

Vin a-Herbon et al., 2002; Parsons-Hubbard, 2005). These techniques have proven useful in

delineating different depositional environments but concern can be raised as to how reliable these criteria are after burial and diagenesis.

The ecological approach includes methods such as considering individual habitat preferences within the death assemblage and comparing them to the environment in which they were collected to determine if they have been removed from their original life habitat (e.g. Miller et al., 1992; Gardiner, 2001). Other ecological methods involve comparing niche or feeding guild compositions among different modern environments to determine if unique assemblages are formed for unique environments (e.g. Zuschin and Hohenegger, 1998). When two or more strategies are combined to establish spatial fidelity, the conclusions become more robust and a wealth of information can be derived from death assemblages.

A pair of studies on molluscan assemblages from coral-reef associated hard and soft substrates found high spatial fidelity of live assemblages but not always for dead assemblages

(Zuschin and Hohenegger, 1998; Zuschin et al., 2000). When focusing on hard substrates related to coral reefs, there was a strong relationship between mollusc species found dead and those found alive; however, abundances were much lower for dead molluscs than for live and dominant taxa were also different between live and dead samples. These discrepancies were attributed to taphonomic preservation biases. Additionally, in correspondence analysis of samples based on taxonomic composition, live assemblages grouped according to substrate type but death assemblages did not (Zuschin et al., 2000). For soft substrates in proximity to coral reefs, studying taxonomic compositions as well as ecological niche compositions of molluscan death assemblages also revealed patterns of spatial fidelity (Zuschin and Hohenegger, 1998).

These studies were carried out in a bay within the northern tip of the Red Sea and may not have represented a high-energy setting nor is it affected by hurricanes. Another study outside of

hurricane-dominated regions found that in patch reef associated environments molluscan death assemblages also show spatial fidelity based on the proportions of ecological groups present

(Best and Kidwell, 2000a).

Most fidelity studies in reef environments focus on reef corals and molluscs as they are the most common organisms within macrofaunal assemblages in both modern and fossil reefs.

However, a study concerned with foraminiferal death assemblages in the Philippines showed that fidelity to reef habitat exists within these assemblages as well (Glenn-Sullivan and Evans, 2001).

In Jamaican fringing reefs, taxonomic compositions of all biotic constituents of sediments also revealed spatial fidelity (Boss and Liddell, 1987).

An important exception to findings supporting high spatial fidelity includes a study conducted on patch reefs and related environments in an open bay (Gardiner, 2001). Gardiner found that spatial fidelity of molluscan death assemblages did exist prior to the passing of a

Category 5 hurricane (Hurricane Floyd) over the north point of San Salvador, Bahamas. These assemblages, although, contained a high level of out-of-habitat organisms. Following the passage of the hurricane, distinct assemblages related to substrate type were no longer recognizable and exhibited little spatial fidelity.

A study comparing live-to-dead fidelity of reef coral in shallow fringing reefs had mixed results (Pandolfi and Minchin, 1995). Most coral species found in death assemblages were also found living; however, the coral species found alive were not found dead within the same habitat. Reef coral live/dead fidelity was lower in their two higher energy settings where assemblages were said to appear comparable to allochthonous assemblages (Pandolfi and

Minchin, 1995). Their finding is the opposite of what was discovered for molluscan assemblages from temperate climates (Kidwell and Bosence, 1991).

This study addresses spatial distributions of molluscan death assemblages in an open- coastal setting frequented by hurricanes. In these locations, soft and hard substrates lie within close proximity to one another and there are no seagrass beds or embayments to trap sediments.

Furthermore, three reefs were examined within the same bay to determine if molluscan skeletal material was distributed in similar ways among beach-to-reef transects. Differences or similarities within the same bay can provide insight into how broadly generalizations about spatial fidelity within molluscan death assemblages can be used.

TABLE 1: Modern reef studies concerning spatial fidelity. Organisms Reef Studied Method Findings References Studied Shallow fringing reefs (<4 m Reef Coral Live/dead fidelity; High energy areas: low fidelity; low energy Pandolfi and water depth) species counts areas: high fidelity Minchin, 1995

Restricted lagoon and patch Molluscs Abundance counts Pre- and post-hurricane samples showed high Miller et al., 1992 reef (<5 m water depth) spatial fidelity

Open bay and patch reefs (<5 Molluscs Abundance counts Pre- and post-hurricane samples showed low Gardiner, 2001 m water depth) spatial fidelity

Soft-bottoms on reef slopes Molluscs Abundance counts High spatial fidelity of assemblages Zuschin and (<40 m water depth) Hohenegger, 1998

Hard substrates on reef slopes Molluscs Live/dead fidelity Species found dead also found live; live/dead Zuschin et al., 2000 (<40 m water depth) abundances do not match; environmental patterns in live distributions were not found in dead

Patch reefs (12-29 m depth) Molluscs Proportions of High spatial fidelity of molluscan remains at Best and Kidwell, ecological groups the facies level 2000a

Steep-sided platform reef Foraminifera Abundance counts Abraded foram assemblages show fidelity to Glenn-Sullivan and habitat preferences; storms have little effect Evans, 2001

Fringing reefs down to forereef All biotic Abundance counts High spatial fidelity despite limited down- Boss and Liddell, slopes (1-75 m depth) constituents slope transport 1987

CHAPTER TWO

METHODS

Geologic Setting

San Salvador, Bahamas, is located about midway down and on the easternmost edge of the Bahamas archipelago (Figure 1a). The north-south oriented kidney-bean-shaped island is positioned at 24 o 3' N and 74 o 30' W where it is isolated from the rest of the Bahamas carbonate bank surrounded by 4000 meter-deep water. It is a small, carbonate island (11.2 km from east to west at its widest; 19.25 km from north to south at its longest) and covered with lakes (Figure

1b), elongate dune ridges, and caves. San Salvador is nearly surrounded by fringing and small barrier reefs; it has numerous offshore cays except in the region of Fernandez Bay located in the southern portion of the island’s west flank. The northward-flowing Antilles Current delivers warm, tropical water to San Salvador’s east coast and helps maintain seasonal surface temperatures of 22-32 oC in the summer and 17-27 oC in the winter. San Salvador receives most of its rain from September to November which coincides with the peak of the Caribbean hurricane season (Gerace et al., 1983).

This study was conducted within Fernandez Bay (Figure 1b), a gently curving bay which has little protection from the open ocean other than that it is located on the west (leeward) side of the island, while prevailing winds and waves come in from the east. The shoreline of Fernandez

Bay is dominated by cemented beachrock as is the extensive intertidal region that extends outward approximately 25 meters from an average high-tide shoreline. Seaward from the beachrock in the northern two patch reefs studied, the seafloor is dominated by hardgrounds

(Figure 4a). These consist of flat, smooth ancient beachrock as well as cemented Porites spp. rubble forming pocketed hardgrounds with small amounts of carbonate sand. Seaward beyond

Snapshot and Telephone Pole Reefs, carbonate sand dominates. A dominantly southward- flowing current sweeps the west side of the island and is strongest at the southern end of

Fernandez Bay where large-scale two-dimensional current ripples interfere with large-scale two- dimensional vortex ripples in the sands around Lindsay Reef, the southernmost patch reef that was studied (Figure 4b) (Gerace et. al 1998; personal observation).

FIGURE 4B: Map showing orientation and substrate relationships for Lindsay Reef.

FIGURE 4A: Map showing orientation and substrate relationships for Snapshot and Telephone Pole Reefs.

Hurricane Frances

The eye of Category 3 Hurricane Frances passed over the southwest corner of San

Salvador (Figure 2) on the afternoon of 2 September 2004 with wind speeds nearing 205 km/hr.

It had reached its maximum wind velocity of 231.5 km/hr approximately 14 hours prior to

making landfall but was declining in strength as it pummeled through the Bahamas (Bevin,

2004). A minimum surface pressure of 948.1 mb was recorded on San Salvador at 20:00 on

September 2 (Bevin, 2004). Most damage resulting from Hurricane Frances occurred on the north and east coasts of the island (in the right front quadrant of the hurricane) where extensive damage occurred in the United Estates settlement. Major structural damage to the west coast, or leeward side of the island, was limited although minor damage occurred (Neely, 2006).

Despite the fact that Frances came about an hour and a half before low-tide, the storm surge associated with Hurricane Frances on the southeast side of the island was shown to be more extensive than anything encountered in the last three hurricanes to hit the island including the Category 5 Hurricane Floyd that passed just north of San Salvador in 1999 (Thomason et al.,

2005). Storm surge at Sandy Point, the southwestern tip of the island, was estimated between 3-

4 meters (Parnell et al., 2004). Lying just north is Fernandez Bay, where rocks and sand on the road indicated storm surge was above the level of the sea wall (Parnell et al., 2004). This would require nearly 2 meters in storm surge above a typical low tide.

Field Methods

Three transects were sampled in Fernandez Bay including two very similar reef sites

(Snapshot and Telephone Pole) consisting largely of hardgrounds as well as one site with reef crests oriented oblique to shore and consisting mostly of fine sand (Lindsay Reef; Figure 4). The three transects range from 225-300 meters long and covered a water depth range from 0-6 meters

(Table 2; Figure 5). These sites were used to determine if reefs within the same bay were affected similarly by the hurricane.

TABLE 2: Length, number of sites, and depth range for each of the three transects.

Transect Length (m) Number of Sites Depth Range (m) Snapshot Reef 270 10 0-5.5 Telephone Pole Reef 300 11 0-6.1 Lindsay Reef 225 10 0-4.6

FIGURE 5: Depth profiles and substrate types for the three transects.

Snapshot Reef (Snap) and Telephone Pole Reef (TP) transects extended perpendicular from shore along an azimuth of 270 degrees. Transect lengths were 270-meters and 300-meters long for Snap and TP transects, respectively. These transects consisted of mostly hardground and reef substrates with Telephone Pole Reef including one sandy site. They were spaced approximately 350 meters apart in the central region of Fernandez Bay and were approximately six meters deep at their deepest part. Lindsay Reef (Lind) transect was oriented along an azimuth of 240 degrees extending oblique to shore and passing perpendicularly across two roughly linear-shaped patch reefs whose axes are oriented along an approximate azimuth of 330

degrees. Lindsay Reef transect consisted largely of sandy sites except for the patch reefs. This site is located in the southern end of the bay approximately 3000 meters south of Telephone Pole

Reef with a maximum depth just over 4.5 meters. A detailed description and field assessment was recorded at each sample interval describing substrate type, bedforms, algal cover, and bioturbating organisms (Appendix A).

Transects began at the high-tide watermark on the beach and ended on or just past the patch reefs. Sampling was evenly spaced at 30-meter intervals along the three beach-to-patch reef transects except at Lindsay Reef where additional samples were added within the 30-meter intervals in order to include sampling on the narrow patch reefs. Collections at each interval consisted of ten-minute equal time searches conducted by two researchers within a two-meter radius of the site marker. The researchers collected as much molluscan skeletal material as possible in the upper 5-centimeters of sediment within the sample circle. Samples were collected from the transects twice: the first collection was in mid-January 2005, four months after the passage of Hurricane Frances; and the second, in mid-June 2005, ten months after the passage of

Hurricane Frances. A total of 12,963 individual mollusc shells were collected using these methods.

Transect Substrate Descriptions

Four main substrate types were differentiated and include: beach, subtidal sand, subtidal hardgrounds, and live reef (Table 3). Beach sampling stations were centered on the high-tide mark. As a result, half of the sampling area was in uppermost intertidal and half of the area included supratidal sand. These samples were collected in sand at all three transects but were

TABLE 3: Generalized descriptions of environment types.

Substrate Description Live Molluscs Found

Beach Sand substrate located at the N/A high-tide water mark on the beach

Subtidal hardground Cemented surfaces; can be very Astraea caelata, Astraea phoebia, Batillaria minima, Cerithium atratum, flat or pocketed by Cerithium eburneum, Cerithium algicola, Cerithium guinaicum, cementing of coral rubble; < Cerithium litteratum, Columbella mercatoria, Conus jaspideus, Conus 1 cm sand veneer mus, Conus spurious, Crassispira nigrescens, Cymatium nicobaricum, Latirus sp., Mitra nodulosa, Natica canrena, Polinices lacteus, Tegula fasciata, Arca zebra, Chione pygmaea, Dentalium antillarum, Divaricella dentate, Glycymeris pectinata, Glycymeris undata, Lima scabra

Subtidal sand Unconsolidated sand; often Olivella minuta, Olivella nivea, Polinices hepaticus, Pusia albocincta, riddled with Callianassa sp. Divaricella quadrisulcata, Strigilla pisiformis burrows; large-scale, 2-D ripples common; sampled within upper 15 cm

Patch reef Topographic highs consisting of Astraea phoebia, Cerithium eburneum, Cerithium algicola, Cerithium high proportions of live guinaicum, Cerithium litteratum, Cerithium lutosum, Modulus coral; sampling conducted modulus, Nassarius albus, Natica sp., Polinices lacteus, Strombus within pockets on reefs or gigas, Tegula fasciata, Glycymeris pectinata, Glycymeris undata, sand immediately below Laevicardium laevigatum, Pectin sp., Strigilla pisiformis, Tellina reefs squamifera

near beachrock at both Snapshot and Telephone Pole Reef transects. Subtidal sand was listed as any sandy site below mean low tide; it should also be noted that all sand and hardground sites that were not beach sites were below low tide. Subtidal hardgrounds were often flat, cemented surfaces exposed on the seafloor. These hardgrounds frequently had algal turfs growing on them and sometimes trapped thin (<1 cm) veneers of sand. They also included varying amounts of pits and dead coral rubble. Hardgrounds yielded most of their death assemblages from sampling within rubble-filled pits in the hardground or from sediment trapped within algal turf. Live reef sites were those found on or very near live patch reefs. Sampling at live reef sites occurred either within rubble-filled pits on the reef, or debris piles directly adjacent and underneath live reefs.

Laboratory Methods

Individual skeletal fragments including live specimens (>2 mm) were identified to species level wherever possible using four standard references: Warmke and Abbott (1962),

Abbott (1974), Humfrey (1975), and Abbott and Morris (1995). Species that were often hard to differentiate were lumped into genera. Counts of identifiable fragments, whole individuals, and identifiable individuals were all recorded. Identifiable fragments were regarded as any fragments that could be positively identified. Whole individuals were those skeletal fragments that were complete, or roughly greater than 90 percent complete. Identifiable individuals were regarded as any gastropod or scaphopod, either whole or fragment, containing an intact apex; or, for bivalves, half the number of valves with umbos intact.

Treatment of Molluscs in Relation to Spatial Fidelity

Substrate preferences of the taxa were compiled from the following sources: Warmke and

Abbott (1962), Abbott (1974), Humfrey (1975), Stanley (1981), Hamilton and Winter (1984),

Miller et al. (1992), Abbott and Morris (1995), Gardiner (2001), and my own observations. Taxa were grouped depending on whether they lived on soft or sandy substrates, hardgrounds, live reef, or substrate preference not determined (Appendix B). For each sample, the percentage of individuals from each of the four categories of substrate preferences was calculated. Samples consisting of more than 50% mollusc individuals requiring a different substrate than that upon which they were collected were considered mostly allochthonous assemblages (out-of-habitat assemblage). Based on this 50% value, it was then possible to evaluate whether a particular reef site, environment type, distance from shore, or other environmental parameter more commonly yielded allochthonous assemblages.

Percentages of live species found dead, percentages of dead species found alive, gastropod-to-bivalve ratios, and percentages of gastropod shells that had been collected with hermit crabs living in them also were calculated for each sample; they were also pooled for environments and reef sites.

Fragmented Ratios

For gastropod data only, any identifiable fragment was counted as a fragment. Fragments were not totaled in the abundance counts for each taxon unless they had features to identify them as an individual; but, if they were identifiable as a member of that taxon, their counts were tallied as a fragment. Because fragment counts were often greater than the abundance counts of individuals for some taxa, direct percentages of the overall abundance that consisted of

fragments could not be obtained. Instead, a fragmented ratio was used; the fragmented ratio was calculated as follows:

Fragment ratio = fragment count / (fragment count + whole count)

Where:

Fragment count = total number of fragments counted regardless of whether they

represent an individual specimen

Whole count = total number of whole molluscs collected

By using this metric, no fragmented ratio values were greater than one. A fragmented ratio of zero means there were no fragments in that sample, only whole individuals. On the contrary, a fragmented ratio of one means there were no whole individuals in that sample, only fragments.

Diversity Metrics

Three main diversity metrics were calculated for each sample and then for data pooled by environments and reef sites: Species richness, Shannon entropy, and evenness. The following formulas were used for these calculations:

Species Richness (S):

S = total number of species identified

Shannon Entropy (H ′) (Margalef, 1958):

H′ = - ∑ pi ln pi

i = 1

where:

S = species richness

pi = ni / N

ni = number of individuals in each species

N = total number of all individuals

Evenness (E H) (Pielou, 1966):

EH = H ′ / ln S

Statistical Analyses

Multivariate ordinations were used to examine spatial variability of sample taxonomic compositions from beach-to-reef environments. Reduced datasets were created for multivariate analyses in order to eliminate the risk that the presence or absence of rare taxa was an artifact of limitations in sampling. Two different culling procedures were compared: (1) samples containing fewer than two taxa (depauperate samples) and taxa occurring in fewer than two samples (singletons) were removed; (2) the second reduced dataset eliminated many more rare taxa by only including taxa whose combined counts represented greater than one percent of the total dataset while also eliminating depauperate samples as in the first reduced dataset. Prior to multivariate analyses for both reduced datasets, abundance values for each taxon within samples

were transformed as a percentage of the total abundance for that taxon and then transformed as a percentage of the total abundance collected for each. The percent transformations were performed to avoid the possibility of calculated similarities being controlled by overall abundances rather than taxonomic compositions (Miller, 1988). Similarity coefficients for use in multivariate ordinations were calculated using the Bray-Curtis coefficient (Bray and Curtis,

1957).

Data analyses were performed using the R environment for statistical computing (R

Development Core Team, 2005). In particular, all multivariate analyses were performed using the Vegan package for R (Oksanen et al., 2005). Relative abundance data of identifiable individuals were analyzed with Detrended Correspondence Analysis (DCA) and Non-metric

Multidimensional Scaling (MDS) as each of these two ordination techniques have differing success rates in detecting, or failing to detect, ecological gradients (Holland and Patzkowsky,

2006). The double-standardization was preceded by a square-root transform for MDS analyses to further reduce the effects of samples and taxa with large abundances dominating the results of multivariate ordinations. All multivariate analyses were performed on similarity matrices using

Bray-Curtis distance for datasets from January and June separately, then for both months combined.

Procrustes tests (PROTEST) were also used to evaluate similarity in different ordination techniques. PROTEST is a superimposition technique that rotates and rescales a matrix for comparison to find maximum similarity with a target matrix (Mardia et al., 1979) while parameters are set to maintain the symmetry of each matrix. It also provides a correlation coefficient and has been shown to be a very powerful tool in comparing different ordinations

(Peres-Neto and Jackson, 2001).

Finally, agglomerative nesting cluster analysis (AGNES; Kaufman and Rousseeuw,

1990) was used in order to assess similarity-based groupings of samples and taxa using the

Cluster package for R-Cran (Maechler, 2005). Two-way R- and Q-mode cluster analyses were performed on a dissimilarity matrix using Bray-Curtis distance created from the double-

Wisconsin standardized dataset.

CHAPTER 3

RESULTS

Dataset Composition

The entire data set consisted of 128 samples covering 64 sample sites with two replicate samples collected from each site (Table 4); the size of combined replicates for each site (death assemblages) ranged from the smallest (most depauperate) consisting of two individuals up to the largest containing 2,342 individuals. Comparisons of January and June reveal that many more dead specimens were collected in January while live specimens were more abundant in

June.

Table 4: Numbers of live molluscs and dead molluscs found by month and by transect. # Live # Live # Dead # Dead Mollusc Mollusc Mollusc Mollusc # Sites Individuals Species Individuals Species Reef Sites Combined 64 123 32 12963 193 January 31 41 14 7685 172 June 33 82 26 5278 154

Snapshot Reef 20 52 19 2537 119 January 10 21 9 1140 96 June 10 31 13 1397 99

Telephone Pole Reef 22 59 18 1894 123 January 11 16 7 1087 104 June 11 43 14 807 102

Lindsay Reef 22 12 8 8532 172 January 10 4 3 5458 155 June 12 8 6 3074 125

Live-Dead Distributions by Time and Transect

Comparisons of percent live taxa found dead and percent dead taxa found live are fairly consistent across transect sites and substrate types (Table 5); the highest value for dead taxa found live is 16 percent. These numbers are all very low because there were so few live molluscs found during the study. However, percentages of dead taxa found live are consistently higher in June than January because many more live molluscs were collected in June.

Percentages of live taxa found dead are always higher (67%-100%) except at June Snapshot sand where the one live mollusc taxa was not also found dead. In all substrates for both months at

Lindsay transect, all taxa found live were also found dead. Snapshot hardgrounds had lower values for live taxa found dead (January: 78%; June: 73%) and June reefs had low values at

Snapshot and Telephone Pole transects (Snapshot: 67%; Telephone Pole: 80%).

June samples yielded a greater number of live individuals than January yielded for all substrate types except beaches (no live molluscs for either month). On the contrary, January samples produced many more dead individuals in almost all cases. The exception is the pooled data for Snapshot transect; the amount of dead shell material here was greater in June than it was in January. Some of the disparity between the numbers of dead individuals collected in January versus June can be explained by several Lindsay transect samples that yielded drastically greater numbers of molluscan hardparts in January. Two January Lindsay sample sites consisted of large-scale, two-dimensional current ripples whose troughs were filled 1-2 cm deep with small

(2-6 mm) shell material; only one analogous sample was found in June. Other current ripples in

June lacked the coarse skeletal debris in their troughs and were mostly stabilized by diatom mats.

In addition, two reef samples from Lindsay transect in January yielded larger amounts of shell material than did analogous sites in June.

TABLE 5: Live-dead fidelity determined for all data combined, data for each individual reef sites, and data for each substrate type. January % June % Live January % June % Dead % Live Taxa Live Taxa Taxa Found % Dead Taxa Dead Taxa Taxa Found Transect/Substrate* Found Dead Found Dead Dead Found Live Found Live Live

All transects combined 97 (31/32 spp.) 100 (14/14 spp.) 92 (24/26 spp.) 16 (31/193 spp.) 8 (14/172 spp.) 16 (24/154 spp.)

Snapshot Reef 84 (16/19 spp.) 78 (7/9 spp.) 79 (11/14 spp.) 13 (16/119 spp.) 7 (7/96 spp.) 11 (11/99 spp.) Hardgrounds 82 78 73 18 11 14 Sand ------No Sand Sites at Snapshot Reef Transect ------Reef 80 100 67 6 4 5

Telephone Pole Reef 100 (18/18 spp.) 100 (7/7 spp.) 86 (12/14 spp.) 15 (18/123 spp.) 7 (7/104 spp.) 12 (12/102 spp.) Hardgrounds 90 80 100 13 8 16 Sand 50 100 0 2 2 0 Reef 82 100 80 10 5 13

Lindsay Reef 100 (8/8 spp.) 100 (3/3 spp.) 100 (6/6 spp.) 5 (8/172 spp.) 2 (3/155) 5 (6/125 spp.) Hardgrounds ------No Hardground Sites at Lindsay Reef Transect ------Sand 100 100 100 3 2 3 Reef 100 100 100 3 1 5

* Beach samples not included; no live molluscs were collected on any beach

Overall, numbers of dead individuals were much greater at Lindsay transect than at any other transect: roughly 71 percent of the total dead molluscs in January were collected along

Lindsay transect; in June, only about 58 percent of the total dead abundance is represented at

Lindsay transect. Likewise, Snapshot and Telephone Pole assemblages accounted for 15 and 14 percent of the January dataset respectively. In June, Snapshot and Telephone Pole assemblages were responsible for 26 and 15 percent of the dataset respectively.

Contributions of Rare and Abundant Taxa

When the contributions of individual taxa to the whole dataset were calculated separately, it was found that 171 of the 193 taxa identified have abundances that, individually, contribute less than 1 percent of the total dataset. Additionally, the summed abundances of the 20 most abundant taxa account for 75 percent of all individuals counted with the top seven taxa comprising over 50 percent of the data set (Table 6).

Although rare taxa are ubiquitous throughout the data set, plots of number of taxa versus number of specimens for January and June both show a leveling off effect on the curves for sandy sites including beaches (Figure 6). This would suggest that upon sandy substrates, sampling was sufficient such that it would take exhaustive sampling measures to obtain a limited amount of additional information (see Foote and Miller, 2007).

Hard substrates, which include reef sites and hardgrounds, did not exhibit the leveling off effect in these plots. Two reef samples from the January dataset appear to level off, but these points represent samples collected in sand directly underneath the reef and therefore would be expected to contain reef or mixed sand and reef organisms. Thus, hard-substrates with pockets

of sand may yield significant additions to the data set although hard substrates on the whole were depauperate of skeletal debris compared to soft substrates.

TABLE 6: Abundances of individual taxa and their percent contributions to the entire dataset; includes only taxa with total abundances greater than 50. Cumulative Percentage of Abundance Percent of Dataset Dataset Cerithium litteratum 1709 13.2 13.2 Cerithium spp. 1327 10.2 23.4 Americardia guppyi 914 7.1 30.5 Barbatia cancellaria 720 5.6 36.0 Bulla striata 716 5.5 41.5 Transennella sp. 660 5.1 46.6 Columbella mercatoria 493 3.8 50.4 Divaricella sp. 449 3.5 53.9 Barbatia domingensis 371 2.9 56.8 Glycymeris pectinata 323 2.5 59.3 Tellina radiata 266 2.1 61.3 Olivella nivea 235 1.8 63.1 Polinices lacteus 235 1.8 64.9 Hipponix antiquatus 229 1.8 66.7 Conus jaspideus 223 1.7 68.4 Chione cancellata 199 1.5 70.0 Tegula fasciata 195 1.5 71.5 Astraea tecta 152 1.2 72.6 Linga pensylvanica 152 1.2 73.8 Modulus modulus 137 1.1 74.9 Strombus sp. 132 1.0 75.9 Tricolia sp. 129 1.0 76.9 Daphnella lymneiformis 121 0.9 77.8 Dentalium sp. 118 0.9 78.7 Nassarius albus 106 0.8 79.5 Natica canrena 103 0.8 80.3 Arca sp. 101 0.8 81.1 Strigilla sp. 95 0.7 81.8 Brachidontes domingensis 90 0.7 82.5 Chama sp. 79 0.6 83.2 Cymatium sp. 72 0.6 83.7 Fissurella barbadensis 70 0.5 84.2 Diodora minuta 68 0.5 84.8 Acmaea spp. 67 0.5 85.3 Petaloconchus sp. 67 0.5 85.8 Nerita sp. 62 0.5 86.3 Lima scabra 60 0.5 86.7 Tellina similis 55 0.4 87.2

A. B.

C. D.

FIGURE 6: Sampling curves with colored points distinguishing samples collected from each of four different substrate types for January (A) and June (B), followed by sampling curves excluding shell hash beds and beaches for January (C) and June (D).

When sample sites such as shell hash beds and beaches were removed from the data analysis, the sampling curves appear to show little distinguishable leveling off and plot similarly in January as they do in June for subtidal sands and hardgrounds (Figure 6). The rise in species richness as sample size increases is approximately constant with the possible exception of hardgrounds in June, but this observation is largely based on only one data point. Reefs, on the

other hand, plot very differently. January reef samples plot exclusively on the farthest and highest portions of the curve, indicating high abundance and species richness. Reef samples from June are uniformly dispersed throughout the curve. Thus the reef sample sites exhibited the biggest difference in terms of general sample size properties during the temporal intervals of this study.

Out-of-Habitat Transport of Molluscan Skeletal Remains

Overall Temporal Trends

Nearly 65 percent (8351 of 12963 molluscs) of all molluscs recorded in the study were taxa with specific substrate preferences (Table 7). Just over 35 percent (4612 of 12963 molluscs) of molluscs fell into the category of taxa for which no specific substrate preference was defined for one of three main reasons: (1) the taxa may be non-specific to substrate, (2) that literature was not found to support a particular preference, or (3) contradictory literature was found with respect to substrate preference.

In January, the percentage of molluscs found and described as not associated with a particular substrate type was always higher (from 3 to 14 percent greater) than was found in

June. Much of this difference can be accounted for by higher representation of Cerithium species in January, particularly from the shell hash beds in large-scale two-dimensional ripple troughs at Lindsay transect; shell hash beds in June were rare.

TABLE 7: Percent of molluscs collected with specific habitat preferences. % % % Month Site Abundance % N/A % HG Sand Intertidal Reef Both All 12963 35.6 25.4 36.9 2.0 0.8 January All 7685 42.6 24.5 31.8 1.2 1.1 June All 5278 25.4 26.9 44.4 3.3 0.5

Beach Samples

The most notable difference in molluscan death assemblages from beach substrates

(Appendix C) between the January and June collection intervals is that percentages of sand- dwelling molluscs dropped by about 10 percent (56.4% and 45.5% respectively) while the percentage of intertidal molluscs rose by nearly 10 percent (2.7% and 11.8% respectively).

However, beach samples contained over 88% and 97% molluscs that do not tolerate intertidal conditions for June and January respectively. As a result, beach sites contained the highest proportions of out-of-habitat molluscs within their death assemblages.

Hardground Samples

Within hardground samples, the percentage of hardground molluscs remained steady for both January and June. Furthermore, the two collection intervals showed remarkable similarity in the proportions of different types of molluscs found. An unexpected result for both January and June is that percentages of hardground-affiliated molluscs (17.9% and 17.5% respectively) were lower than those found in any other substrate grouping for either month. Moreover, the average percentage of sand-affiliated molluscs in January hardgrounds (40.8%) was higher than in January at sand sites (37.2%). Although these hardgrounds cannot be shown to have greater than 50% out-of-habitat molluscs, they are clearly mixed assemblages because their proportions of sand-affiliated molluscs are so much higher. Interestingly, proportions of molluscs from each group at hardgrounds were more consistent between January and June sampling than at any other substrate.

Subtidal Sand Samples

For subtidal sand samples, percentages of sand-affiliated molluscs greatly increased from

January to June (37.2% and 50.7% respectively) and were accompanied by a drop in percentages of non-affiliated molluscs (38.0% and 23.9% respectively); this can be attributed to a large decrease in the amount of individuals from Cerithium spp. collected at sand sites in June. The constituency of sand-affiliated molluscs in June (50.7%) was higher than all other averages except January beaches where the Lindsay beach sample inflated the average to 56.4%. This reflects the highest spatial fidelity detected in the data set using this method of molluscan habitat preferences. Greater than 50% of the collection could be unequivocally considered within habitat.

Reef Samples

Reef sites in January were characterized by the highest percentages of hardground- affiliated molluscs (32.8% for each month). Similar to sand sites, reef sites saw a drop in percentages of non-affiliated molluscs complimenting a rise in sand-affiliated molluscs. Overall, molluscan composition did not change greatly at reef sites. Assessing habitat fidelity with reef sites is not straightforward as they often consisted of hardgrounds with large pockets of sand; occasional sampling of sand directly below reef overhangs added to this tendency towards mixed substrates. Reef sites for both months were distinguished apart from other substrates for having the most evenly distributed proportions of non-affiliated, sand, and hardground molluscs.

Based on proportions of molluscs represented by substrate preference, June samples from beach and sand sites showed an increase in habitat fidelity with respect to January samples. At hardground and reef sites, little compositional change was observed between the two collection

intervals. Beaches and hardgrounds revealed the lowest recognizable habitat fidelity; high numbers of non-affiliated molluscs at hardgrounds leave a great deal open to interpretation whereas beaches certainly consist predominantly of transported skeletal debris.

Relative Contributions of Gastropods and Bivalves

Of the entire data set, nearly 60 percent of individuals collected were gastropods.

Separating the datasets by month showed that gastropods accounted for more than two-thirds of all individuals collected in January (66.9%) but they did not even amount to half of the total individuals in June (48.7%). The highest proportion of gastropods for January was found on sandy substrates (77%), followed by reefs (68%), and then hardgrounds and beaches (51% and

41% respectively). In June, the highest concentrations of gastropods were found on beaches

(62%), followed by reefs (52%), then hardgrounds (50%), and finally sandy substrates (42%).

The biggest differences between the two months are the result of many shell beds at Lindsay sands that contained high proportions of gastropods in January. Additionally, several reef sites at

Lindsay and Telephone Pole transects had high concentrations of gastropods in January.

Patterns of Hermitting within the Dataset

Live hermit crabs captured throughout the study easily outnumbered live molluscs with

191 in total. Live molluscs were represented by 101 gastropods, 21 bivalves, and one scaphopod. Live hermit crabs were more prevalent in January than June whereas the opposite is true for all live mollusc taxa. Hermitted gastropod shells were commonly found on hardground and reef substrates (Table 8). At reef sites, hermit crabs occupied over three percent of the gastropod shells; on hardgrounds, 15 percent and 21 percent of all gastropod shells were

occupied by hermit crabs in January and June, respectively. Lindsay transect had the lowest instance of hermitted gastropod shells; Snapshot transect had the highest overall hermitted percentages of 9.5 percent in January and 6.5 percent in June; Telephone Pole transect percentages were only half as high as Snapshot transect.

TABLE 8: Percent of gastropods shells found hermitted at time of collection. Percent of gastropods that were hermitted at time of collection By Substrate Combined Months January June Beach 0.0 0.0 0.0 Sand 0.5 0.4 0.9 Hardground 17.9 15.3 21.0 Reef 3.2 3.2 3.3

By Reef Site Combined Months January June Snapshot Reef 7.6 9.5 6.5 Telephone Pole Reef 3.8 4.5 2.8 Lindsay Reef 1.0 1.0 0.8

Patterns of Gastropod Fragmentation within the Dataset

Counting methodologies prohibited the finding of fragmented ratios for bivalves.

Therefore, all fragmented ratios are for gastropods and scaphopods only. Within beach, subtidal sand, and hardground substrates, mean fragmented ratios were higher in January than in June

(Table 9). Fragmented ratios for reefs were slightly higher in June. Beaches had the lowest fragment ratios in both January and June (0.485 and 0.275 respectively) and showed no statistically significant difference between the two months using two-sample t-tests. Sand and hardground sites showed the greatest disparity between the two months and differences in both cases were statistically significant (Table 7). Reefs had the highest average fragment ratios in

June (0.578) and second highest in January (0.553); the difference between the two months, like beaches, was not statistically significant.

TABLE 9: Mean gastropod fragmented ratios and t-tests of January versus June. Mean Fragment Ratios 95% Confidence Intervals* Substrate All Data January June Lower Upper All 0.538 0.628 0.450 0.102 0.254 Beach 0.376 0.530 0.222 -0.190 0.807 Sand 0.560 0.615 0.512 0.014 0.194 Hardground 0.528 0.638 0.398 0.098 0.381 Reef 0.586 0.660 0.527 -0.003 0.270

* 95% Confidence Intervals from Welch 2-sample t-tests Shaded boxes indicate statistically significant differences at alpha = 0.05

Two-sample t-tests were also used to compare fragmented ratios between substrate types within each temporal interval (Table 10). No statistically significant differences occurred with this comparison for either month.

TABLE 10: Statistical comparisons of fragmented ratios between substrates types. Lower and upper 95% confidence intervals between substrates* Beach Sand Hardground Sand -0.258 0.087 X X Hardground -0.271 0.055 -0.130 0.085 X

January January Reef -0.301 0.041 -0.172 0.083 -0.165 0.121 Sand -0.818 0.239 X X Hardground -0.665 0.312 -0.016 0.243 X June June Reef -0.823 0.213 -0.121 0.091 -0.263 0.006 * Confidence intervals from Welch 2-sample t-tests No statistically significant differences at alpha = 0.05

Diversity Metrics

When comparing diversity metrics of the death assemblages based on subsets of the data pooled by transects (Table 11a), Snapshot exhibited the lowest species richness (S) in January and June. Ironically, as Snapshot transect was the least diverse in terms of species richness for

molluscan death assemblages, it was the most diverse by the same metrics for live assemblages of molluscs. Values for Shannon entropy (H') and evenness (E) were intermediate with respect to the other two transects.

Telephone Pole transect was consistently more diverse and more even than the other transects in terms of Shannon entropy and evenness for both sample periods. However, its species richness was intermediate with respect to the other transects.

The highest species richness was found at Lindsay transect where January species richness was far greater than the next highest transect. Lindsay transect Shannon entropy was lowest among the transects in January and slightly higher than the lowest in June. Evenness values at Lindsay transect were conspicuously low within the dataset. This observation, as well as low Shannon entropy is due to the aforementioned shell hash beds that yielded very high numbers of the most common taxa, mainly Cerithium litteratum and other species of Cerithium , countered by a plethora of rare taxa.

When comparing diversity metrics for subsets of the data based on the substrate they were collected additional generalizations can be made (Table 11b). Beaches, in comparison with the other three substrates, consistently yielded mid-range abundance, evenness, and species richness values. Hardgrounds consistently had abundance and species richness values that were low while evenness was high when compared to other substrates. Sand sites had abundances and species richness values that were much higher than the other substrates while evenness was lowest in both months. Reefs had the highest Shannon entropy in January and June.

TABLE 11 A: Diversity metrics by transect and month.

Species Transect Month Richness Shannon Entropy Pielou’s Evenness Abundance All Both months 32 2.56 0.40 123 January 14 2.25 0.68 41 June 26 2.41 0.43 82 Snapshot January 9 2.05 0.86 21 June 14 2.21 0.65 31 LIVE Telephone Pole January 7 1.75 0.82 16 June 14 1.78 0.42 43 Lindsay January 3 1.04 0.94 4 June 6 1.73 0.94 8 All Both months 193 3.69 0.21 12963 January 172 3.58 0.21 7685 June 154 3.73 0.27 5278 Snapshot January 96 3.58 0.37 1140 June 99 3.49 0.33 1397

DEAD DEAD Telephone Pole January 104 3.69 0.38 1087 June 102 3.93 0.50 807 Lindsay January 155 3.40 0.19 5458 June 125 3.50 0.26 3074

TABLE 11 B: Diversity metrics by substrate type. Species Substrate Month Richness Shannon Entropy Evenness Abundance Beach January 0 0.00 Inf 0 June 0 0.00 Inf 0 Sand January 3 1.04 0.94 4 June 4 1.33 0.94 6

LIVE HG January 11 2.18 0.80 24 June 16 1.87 0.41 56 Reef January 4 1.27 0.89 13 June 14 2.45 0.83 20 Beach January 89 3.35 0.32 1026 June 87 3.45 0.36 1224 Sand January 139 3.36 0.21 3347 June 122 3.48 0.27 3009 HG January 76 3.42 0.40 609 DEAD DEAD June 74 3.38 0.40 523 Reef January 136 3.57 0.26 2703 June 91 3.91 0.55 522

TABLE 12: Statistical comparisons of mean diversity metrics between substrates using 95% confidence intervals from Welch 2-sample t-tests. Diversity Month Substrate Metric* Beach Sand Hardground S Beach H' n/a n/a n/a

EH S -23.89 35.56 Sand H' -0.54 0.56 n/a n/a

EH -0.30 0.08 S 0.16 56.76 6.31 38.94 Hardground H' -0.14 0.98 0.03 0.79 n/a

BOTH MONTHS MONTHS BOTH EH -0.40 -0.05 -0.24 0.01 S -15.37 41.64 -11.18 25.78 -26.39 -4.26 Reef H' -0.54 0.57 -0.36 0.37 -0.79 -0.02

EH -0.38 -0.01 -0.23 0.06 -0.08 0.14 S Beach H' n/a n/a n/a

EH S -51.49 51.01 Sand H' -0.87 0.66 n/a n/a

EH -0.39 0.14 S -34.46 92.35 0.55 57.82

JANUARY JANUARY Hardground H' -0.33 1.20 -0.04 1.12 n/a

EH -0.54 -0.04 -0.38 0.06 S -57.22 51.64 -33.08 27.98 -49.22 -14.26 Reef H' -1.11 0.58 -0.52 0.20 -1.24 -0.16

EH -0.35 0.14 -0.22 0.27 0.01 0.36 S Beach H' n/a n/a n/a

EH S -56.71 78.80 Sand H' -1.33 1.56 n/a n/a

EH -0.49 0.32 S -52.79 108.85 -6.32 40.30 JUNE JUNE Hardground H' -1.19 1.98 -0.24 0.80 n/a

EH -0.60 0.28 -0.26 0.11 S -54.23 103.20 -10.26 37.14 -13.81 6.72 Reef H' -1.23 1.67 -0.49 0.70 -0.67 0.32

EH -0.71 0.22 -0.33 0.02 -0.20 0.04 Shaded boxes indicate statistically significant differences at alpha = 0.05 * S = species richness; H' = Shannon entropy; EH = Shannon evenness

Diversity metrics for beaches, hardgrounds, and sand sites exhibited only minor differences between January and June. However, reef sites were very different between January and June (Table 11a). January reef sites had abundance and species richness values similar to the highest values found at sand sites while evenness was similarly low. In contrast to this, June reefs had the lowest abundance of any data subset along with species richness that was in the middle of the range. Shannon entropy and evenness for June reefs were higher than any other group.

The results of Welch 2-sample t-tests reveal that some statistically significant differences exist between diversity and substrate types (Table 12). Noteworthy results from these tests are that hardgrounds are significantly different from all other substrates in terms of species richness; evenness of hardground substrates is significantly different from that of beaches; Shannon entropy is significantly different from that found in reefs and sand sites; and, evenness between beach and reef sites is significantly different.

Ordination Techniques Compared

Multivariate analyses of the first reduced dataset, excluding taxa occurring fewer than two times and samples containing fewer than two taxa, revealed little recognizable organization based on transect location, substrate type, or month collected (Figure 7a). Seven labeled samples plotted far to the right in both ordinations. These samples represent seven of the nine least diverse samples in terms of species richness. The majority of hardground samples in MDS and

DCA were vaguely separated from the majority of the other three substrate types, suggesting that hardgrounds exhibited the greatest differences in taxonomic composition. This observation was more pronounced in multivariate analyses of the reduced dataset consisting only of taxa that

individually represent greater than one percent of the complete dataset (Figure 7b). This dataset included the 22 taxa that collectively represented approximately 77 percent of all individuals in the complete dataset. Individuals from the genus Cerithium were responsible for over 30 percent of the reduced dataset (Appendix D).

Ordinations using the dataset only including the 22 most abundant taxa revealed several other trends. Using this reduced dataset produced more simplified ordinations by reducing the

‘noise’ created by the plethora of taxa only found in a handful of samples and allowed for the multivariate analyses to compare patterns associated with more dominant (more likely to be collected) taxa. For MDS and DCA, the data plotted approximately linear along the third dimension of MDS (MDS 3) and the first dimension of DCA (DCA 1). Likewise, MDS 1 and

DCA 2 were relatively similar in that they displayed the same few sites as being distinct from the majority of the points (Figure 7b).

Pearson's R and Procrustes Tests (PROTEST) revealed strong correlations between DCA and MDS axes results; indicating that both ordination methods produced similar results for interpreting spatial distributions of molluscan hardparts. Pearson’s R values were calculated for all combinations of MDS 1-3 and DCA 1-3 to determine the similarity between the DCA and

MDS ordination analyses (Table 13). There were two very significant correlations (in terms of R and p-value) indicating that the correlated axes organized individual samples similarly: the first was between MDS 3 and DCA 1 (R = -0.76; p < 0.0001), and the second was between MDS 1 and DCA 2 (R = -0.86; p < 0.0001). When the plots from Figure 7b were visually compared,

MDS plots would bear close resemblance to DCA plots after being rotated 90 degrees clockwise and reflected across a horizontal plane. Procrustes tests confirmed the close similarity between

MDS and DCA. Comparisons using MDS axes 1 and 3, and DCA axes 1 and 2 revealed a

correlation coefficient of 0.84. These tests confirmed that the two ordination techniques produced similar results for sample scores although using different axes.

FIGURE 7A: Plots displaying results from non-metric multidimensional scaling and detrended correspondence analysis of dataset; all taxa with less than two occurrences and all samples with less than two taxa were removed. Plots on the left are color-coordinated by substrate type and plots on the right are color-coordinated by reef transect where they were collected.

FIGURE 7B: Plots displaying results from non-metric multidimensional scaling and detrended correspondence analysis of data only including taxa representing greater than one percent of the entire dataset. Plots on the left are color-coordinated by substrate type and plots on the right are color-coordinated by reef transect where they were collected.

TABLE 13: Pearson Correlations Coefficients and associated confidence intervals between MDS and DCA axes for multivariate ordinations of abundant taxa only. MDS 1 MDS 2 MDS 3 Lower Upper Lower Upper Lower Upper CI R CI CI R CI CI R CI DCA 1 0.16 0.40 0.59 0.07 0.39 0.52 -0.85 -0.76 -0.64 DCA 2 -0.91 -0.86 -0.77 0.07 0.31 0.52 -0.44 -0.21 0.04 DCA 3 -0.29 -0.05 0.20 -0.60 -0.41 -0.18 -0.43 -0.20 0.05

Highlighted regions represent significant correlations at alpha = 0.05

Multivariate ordinations did not organize the samples into clearly distinct groupings; but when examining plots where the data points have been colored based on what transect they are from (Figure 7b), MDS 3 and DCA 1 represented a gradient where Snapshot sites generally had the lowest values, Lindsay sites had higher values, and Telephone Pole sites had intermediate values along these axes. This indicated that Lindsay and Snapshot samples were most different from one another and Telephone Pole sites shared similarities with both. Plots where the data points were been colored based on what substrate they were collected on also show a gradient along MDS 3 and DCA 1 axes (Figure 7b). In general, hardgrounds had low axis scores, sands had high scores, reef scores spanned the widest range, and beaches have intermediate scores.

This corresponds with the pattern that Snapshot transect was mostly hardgrounds, Lindsay transect was almost all sand, and Telephone Pole transect had patchy hardgrounds and sand sites.

Reef sites had the broadest range of substrate variability because each reef sample consisted of varying ratios of pockets of sand and hardground surfaces.

The other dimensions that were also highly correlated between ordination techniques were MDS 1 and DCA 2. These axes had the greatest range of values and hence the widest range of dissimilarity even though the majority of samples plotted close together. Samples at the extremities of these axes all had a species richness of five or fewer except for JanTP-8, which

only had a species richness of one, and was not used in the analyses. Furthermore, it should be noted that these outlier sites were all collected in June; thus June sample scores exhibited more variability along MDS 1 and DCA 2 than their January counterparts.

Cluster Analyses of Beach-to-Reef Transects

Q-mode cluster analysis

Q-mode cluster analysis of the dataset using the top 22 taxa illustrated that all transects sampled in Fernandez Bay showed remarkable similarity despite their differences. Most of the main taxa were found in most samples and there is little dissimilarity. Snapshot transect stands out separately as having an overall lower species richness and abundance with the exception of its beaches; overall, differences are seemingly unsubstantial. Even remotely discrete clusters cannot be described based on cluster analyses and this was further substantiated by performing cluster analysis on the complete dataset as well as using different methods (e.g. unweighted pair- group average vs. Ward’s, and Euclidean vs. Manhattan metrics).

Q-mode cluster analysis grouped samples into five major groups (Figure 8, A-E) and several smaller associations (Figure 8, F). Cluster A consisted of hardground and reef site samples that were collected in June from Snapshot transect; it is dominated by Tellina radiata,

Cerithium spp., Transennella sp . and Americardia guppyi . Of these four unifying taxa, many occurred in other primary clusters. Although T. radiata was found in many samples from other clusters, its dominance in this cluster set it apart from others. Underlying cluster B reveals that

T. radiata was a dominant taxon found in every Snapshot sample except the two beach samples and was found in no other samples with such dominance.

Cluster B included the rest of the Snapshot samples and several Telephone Pole hardgrounds and reefs. Cerithium litteratum, Divaricella sp., Strombus sp., and Linga pensylvanica were found in all samples of this cluster in addition to Tellina radiata, also found throughout cluster A and C, and Cerithium spp. , found in every sample of clusters A-E.

Cluster C had the highest number of unifying taxa with 14 of 22 taxa that were relatively abundant in every sample within this cluster. Cluster C consisted of several sand sites from

Lindsay, all sand sites from Telephone Pole transect, and all beach sites from Snapshot and

Telephone Pole transects.

Cluster D also was marked by many unifying taxa. In this cluster, 12 taxa are found in every sample, but all of these taxa were found in every sample of at least one other cluster. Most samples in cluster D represented sand and reef sites from Telephone Pole and Lindsay transects.

The only hardground site, JunTP5, was from a thin strip of hardground between a sand site and the beginning of patch reefs and this site could have contained a mix of taxa from adjacent substrates.

The final primary cluster, E, was the only cluster where every sample contains Hipponix antiquatus. This cluster also shared a common trait with cluster D in that every sample contained individuals of Astraea tecta . Samples in this cluster largely represented seaward reef and sand sites that were adjacent to reefs.

Section F was comprised of smaller clusters and singleton samples, and was therefore not considered a primary cluster. These represented the least diverse samples in the group. Samples in section F represented all samples with species richness less than ten and three other samples with species richnesses of 10, 11, and 12. These were the most dissimilar groupings in the cluster analysis. Interestingly, several site numbers in section F (e.g., TP2, TP3, TP8, Lind0, and

Lind3) were represented by both temporal intervals meaning that these sites had consistently low species richness. Section F included nearshore shallow sites as well as deeper, more seaward sites. Telephone Pole transect yielded two more of these sites in June than it did in January;

Lindsay transect yielded three more in June.

R-mode cluster analysis

Three primary clusters and one smaller cluster were distinguished with R-mode cluster analysis but these clusters of taxa revealed few interpretable results. All clusters had a high level of similarity and probably did not represent discreet biological groupings. Also, the three clusters did not contain similarities in substrate or mode of life.

FIGURE 8: AGNES style two-way cluster analysis based on relative abundances of taxa representing >1% of the total dataset using Bray dissimilarity matrix created from double- Wisconsin standardized dataset. Samples are named as follows: month, transect, sample number increasing seaward, and substrate (B = beach; S = sand; H = hardground; R = reef).

CHAPTER 4

DISCUSSION

Comparison of Transects

The three reef sites used in my study (Telephone Pole Reef, Snapshot Reef, and Lindsay

Reef) were examined previously by Peckol et al. (2003) for coral-coverage differences. Based on the presence and absence of stony corals, algae, and fish, they concluded that Lindsay Reef had much higher sediment input, vastly more filamentous/fleshy algae and much less coralline algae. Furthermore, they found that Snapshot Reef and Telephone Pole Reef coral colonies were larger than those at Lindsay Reef. Lindsay Reef, however, had the healthiest corals.

Observations throughout my study agree that Lindsay Reef hosted the fewest and smallest corals while lacking the most prevalent coral at Snapshot and Telephone Pole Reefs ( Montastrea annularis ).

Snapshot and Telephone Pole transects were remarkably similar in terms of location, depth profile, and number of hardground and reef sites. The Telephone Pole transect was sandier than the Snapshot transect but the orientation of Lindsay’s multiple patch reefs as well as

Lindsay’s prominent abundance of sand, sand waves, and Callianassa burrows made it seem the more different transect. Although the Lindsay transect appeared to be the most different among the three reef sites, the molluscan death assemblages showed little appreciable difference from those at Telephone Pole transect. For example, Telephone Pole samples plot closer to Lindsay samples in multivariate plots. Furthermore, reef sites and some hardground sites from Telephone

Pole transect plotted near sand and reef sites from Lindsay in all multivariate ordinations.

Cluster analyses on the data, as well, showed these sites all clustered similarly based on similar relative abundances of the major constituent molluscs.

Comparison of Substrates

The utility of molluscan death assemblages as proxies for life assemblages and for the demarcation of sedimentary facies has been well-established in recent literature (Miller et al.,

1992; Zuschin and Hohenegger, 1998; Zuschin et al., 2000; Best and Kidwell, 2000a; Kidwell et al., 2001; Kidwell, 2002). These studies have taken place in modern environments where sedimentary facies can be mapped out with their respective molluscan assemblages. Also, they have largely shown high spatial fidelity of death assemblages from different sedimentary facies

(Table 1). My study attempted to detect spatial fidelity within molluscan death assemblages at smaller spatial scales than previously documented. That is, I examined sediment-skeletal mixing from beach to patch reefs over a scale of 300 m, rather than shelf-edge fringing reefs to inner lagoon regions over scales of 1000 meters or more (i.e., Miller et al., 1992; Best and Kidwell,

2000a).

Beaches contained the highest proportions of out-of-habitat molluscs. This is where waves are breaking and more likely to carry shells up onto the beach (out-of-habitat). Because of the orbital motion of waves, wholesale transport cannot be associated with wave movement but there may be a net onshore transport of sediment in these shallow-waters. Breaking waves on the beach could push skeletal material onto the beach and while the water is returning through the beach sand, skeletal material gets trapped on the beach surface.

Within my death assemblages, hardgrounds have consistently low abundances and mid- range amounts of out-of-habitat molluscs. Species richness was also significantly lower at the

hardgrounds compared to all other substrate types. After death, molluscs living on hardgrounds may have been swept into adjacent pits and reef framework or they were being cemented over by coralline algae and other encrusters thus preserving the highest fidelity, although unrecognizable through surface sampling as skeletal material has been cemented over (see Zuschin et al., 2000).

Consistency at hardground sites, within the gastropod component of death assemblages could in part be attributed to hermit crabs. Hermit crabs keep proportions of gastropod shells active on the surface of hardground so they do not get cemented over or swept away.

Sand sites in my study showed the highest levels of measurable spatial fidelity based on habitat preferences for mollusc taxa. This may be attributed to the observation that at Lindsay transect and seaward, substrates primarily consisted of sand. This creates a condition in which molluscan skeletal fragments would have to travel farther to become out-of-habitat, thus reducing their odds of doing so. Another factor in helping sand sites maintain spatial fidelity is that it is more difficult to transport shells on sand than on hardgrounds. When a shell is subjected to current on sand, scours form in front of and around the shell and it settles into its scour pits, eventually becoming buried by further sand deposition (Messina and LaBarbera,

2004). Additionally, the orientation of Lindsay’s reef structures could have created a baffle to any kind of transport-inducing currents.

Gastropod fragmentation was high at patch reef sites in my study. A contrasting study conducted in a non-hurricane affected area found that fragmentation was low at patch reef sites

(Best and Kidwell, 2000a). Differences here are probably present because their study focused on bivalves and at patch reefs, many bivalves were cemented in place and not fragmented.

Throughout their other substrates, Best and Kidwell (2000a) found much higher percentages of fragmented bivalves. My skeletal fragmentation results agree more with those in the Northern

Bay of Safaga, Red Sea (Zuschin and Hohenegger, 1998). Numbers of molluscs that were fragmented in the Northern Bay of Safaga were higher in sands between patch reefs. This would be analogous to many of the sandy pits sampled in the present study that inflated my fragmented numbers at reef sites. Reefs showed the highest variability in species richness, Shannon entropy, and evenness metrics; this was probably as a result of the variability of the reefs sampled. As stated earlier, some of the reef samples were on areas with large and deep sand-filled pits while others were almost all smooth, hard surfaces with few pits. Reef sites also consisted of variable depths; some samples were high on the patch reef structure while others were low valleys within the reef complex. This is a variability that must be dealt with when sampling reefs.

Post-Hurricane Temporal Differences in Death Assemblages

Differences in live-dead fidelity and out-of-habitat percentages between January and June did not yield any consistent results. Percent of dead taxa found live was usually higher in June but this was probably an artifact of there being more live molluscs collected in June. The increase in intertidal molluscs within beach death assemblages could suggest a higher degree of habitat fidelity in June as compared to January as one would expect to find intertidal molluscs near the beach. Because the beach sampling sites included a portion of the supratidal, a proportion of these molluscs may technically be out-of-habitat. However, their close proximity to an ideal environment coupled with the fact that concentrations of skeletal material were generally highest at or below the high water mark suggest they had not been transported far.

However, the proportions of intertidal molluscs were still not very high, leaving about 88% of the assemblages out-of-habitat as those molluscs would not tolerate intertidal conditions.

In January, within four months of Hurricane Frances, more molluscan skeletal material was encountered than in June. These numbers were undoubtedly a result of the many coarse shell beds samples, especially along Lindsay transect. It is likely that these concentrated shell beds were the result of winnowing of finer-grained material to leave behind the coarser skeletal material and is possibly an effect of the hurricane that passed through. Fragmented molluscs were consistently higher in January than they were in June on all substrates except at reefs.

Pockets and patches between reefs could have offered protection from waves and finer grained sedimentation allowing for concentrations of skeletal material. Additionally, the productivity on reefs could be higher thus leaving behind more skeletal material; this is reaffirmed by the high numbers of live molluscs found on reefs. Also, hermit crabs were common on reefs and could have been transporting gastropod shells into these areas or at least keeping them from becoming buried, overgrown, or transported away.

Another difference in June was that most of the sand sites had diatom mats coating and stabilizing their large-scale, two-dimensional current ripples. Analogous mats were only noted at one site in January and it was located up against the second major reef complex. Despite the large disparity in abundances, diversity, and fragmentation, differences between collection intervals were not as prominent in multivariate ordinations and cluster analyses based on taxonomic composition. The taxonomic composition of death assemblages from all transects for both months did not change very much. Furthermore, differences in taxonomic composition alone are not distinct enough to consistently decipher various substrates.

The abundance of shell material deposited in troughs of large current ripples that were encountered at Lindsay in January must have been buried by sand when sampling took place in

June. The absence of the shell beds in June explains the drop in abundance of Cerithium species

that were found and also related to the drop in percent gastropods that was observed. It is probable that these were storm-related features as they contained wood fragments and asphalt chunks which clearly would have to be transported from a terrestrial source . This may have indeed been a true storm bed that was later covered by large-scale current ripples. If storm currents were generated flowing southward as predicted (Figure 3), Lindsay reefs could become sediment traps.

The strongest currents that affect San Salvador are documented as north-to-south flowing currents on the leeward side during the winter months (Gerace et al., 1998; personal field observations). These currents weaken in the summer and this could explain findings of current and wave ripples that were stabilized by diatom mats in June. The strong currents in January could have been responsible for the movement of shell material southward in Fernandez Bay.

This would both explain the abundance of shell material in January as well as the overall high sediment load that is attributed to Lindsay transect. As the current slows down in spring, the coarse material would be covered by finer sediments.

CHAPTER 5

CONCLUSION

In conclusion, it is not absolutely clear whether these data presented herein suggest that death assemblages are homogenized and do not retain spatial fidelity or whether major constituents in living communities are generally homogeneous at this scale within Fernandez

Bay. Although gradients seem to appear in multivariate ordinations, they appear more clearly as differences between transects, not substrates. It is clear that subenvironments based on substrate type in Fernandez Bay cannot be differentiated into discreet molluscan death assemblages based on taxonomic composition as was found in several northeastern Caribbean reef and lagoon systems (Miller, 1988; Miller et al., 1992). However, this study found that taphonomic differences do exist between sedimentary facies such as use of fragmented ratios; this is similar to findings of another Caribbean reef and lagoon study that found higher numbers of fragmented molluscs associated with reefs and was able to use many other taphonomic characteristics as well

(Parsons-Hubbard, 2005).

Temporal changes in death assemblages following a major hurricane did not affect taxonomic composition of death assemblages as greatly as was found following Hurricane Floyd

(Walker et al., unpublished work). Changes in patterns of fragmentation as well as abundances seemed to be affected but it is unclear whether this is a seasonal variation based on current patterns, or a result of hurricane-reworked sediments becoming redistributed or buried nine months later. Repeating this sampling regime following a quiet hurricane season could easily provide enlightenment on this question. Two studies in Smuggler’s Cove, St. Croix, separated

by nearly two-decades, found a large decrease in Cerithium litteratum as was also found in my study with sampling intervals separated by only five months (Miller, 1988; Ferguson and Miller,

2007). They were still able to detect environmental transitions based on taxonomic composition but could not explain a notable decline in the C. litteratum . In the present study, it is also unclear what happened to all the individuals of Cerithium species that were found in January but they were mostly associated with the concentrated shell beds.

Some cores would be helpful to see if these or other beds are buried as well as to determine if beds with large amounts of C. litteratum exist. Seasonal snorkeling trips for a few years could also determine if this is just an annual cycle where coarse material is moved in the winter and then covered with finer current ripples that are stabilized by diatom mats in the summer.

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APPENDICES

APPENDIX A

DETAILED SITE NOTES

Snapshot Reef (January 12-13, 2005) Depth (m)/ Live Hard Site Transect Description Algae Other Live Organisms Corals distance (m) 0 0/0 medium sand; 10' from the edge of none none none beachrock; lots of shell hash and cobbles

1 0.6/30 hardground with large sandy pit running UD, AC, PA, RH, DI, none Natica canrena, Cerithium through site; sand covered with Halimeda DA, NE, CH, DI, HA, litteratum, Columbella mercatoria, flakes TU Cerithium eburneum, CT, CS, BS

2 0.9/60 hardground with larger sand pits and a thin CH, LA, SA, DS, DI, SS BS, Columbella mercatoria, veneer of sand trapped in turf BA, HA, RH, MI, CO Chione pygmaea, PP, HB, CR

3 0.9/90 hardground with one large pit running CH, HA, UD, RH, GO, SS, PP, PA CS, Ps, CT, Cerithium eburneum, through site; pit is filled with sand; the DI Tegula fasciata, LS, HB usual green and brown turfs

4 1.5/120 hardground with shallow pockets SA, DI, PA, MI, UD, TU Ms, PA, SS Bs, CS, Ps, Cerithium eburneum, UH, AC, TB, HB

5 2.4/150 hardground with a thin veneer of sand and CH (most common), SA, none BS, OR, Cerithium eburneum, small pits MI, RH, AC, UD, CE, Conus spurius, PH, CT LA, BA

6 3.4/180 hardground with a few pits; most of the MI (most common), SA, SS BS, PU, UH substrate has a thin sand veneer over it AC, UD, RH, HA, CO

7 4.6/210 hardground on landward edge of reef flat MI (common), PG, SA, PP Conus mussa, Conus spurius, PP, with no pits; edge of reef about 20 m away; RH UH, BS thin sand veneer

8 4.3/240 hardground at landward edge of reef; large, MI, SA, NE SS, PP PG, CS, DI, SA, Ps, RS, CC, TB, live Montastrea head just seaward of site; SS, SV, SP, AC, CR, MN small pits have coral rubble in them

9 5.5/270 rubble area on reef between large PA, DI, SA, MI, LI, LO, SS, AA, MC, PG, ZO, PP, EC, Os, Tegula Montastrea heads CH, CO Ds, Es, PB, MA, fasciata, Cerithium litteratum, DC, MF, PA, MU ES, SS, HF, SP, AC, HS, SV

Telephone Pole Reef (January 8-9, 2005) Depth (m)/ Live Hard Site Transect Description Algae Other Live Organisms Corals distance (m) 0 0/0 coarse, sandy beach near beachrock; large cobbles of none none none Montastrea annularis, Siderastrea siderea , and eolianite

1 0.3/30 hardground with abundant Echinometra boreholes; SA, HA, UD, PA, CH SS, DC (rare) EC (common), PN, PO, coral cobbles 2-3" diameter; thin sediment veneer UH (rare)

2 1.2/60 hardground with urchin pits; covered in green algal DI, UD, AC, AV, HA, FF (common), SA, BS (common) mat C ladophora ; a thin veneer of sand over 1" turf LI, CL Ms, SS, Ps (rare)

3 2.1/90 hardground covered with a thin veneer of sediment MI, SA, AC, CH, CO, PA, Fs, SS BS, RS, Cerithium sp. HA, UD, AV, VA, NE, (rare) RH

4 3.7/120 sandy area between coral ridges; seaward edge of a TU none GO, US, DM, CS, Ds continuous hardground; lg. scale wave ripples (common)

5 4.3/150 hardground with large rubble-filled pits; thin veneer SA, MI, DI, TU AA, Ds, Ms, Es Ds, Polinices lacteus, CN of sand trapped in thin algal turf (rare)

6 3.7/180 hardground in reefy area; thick turfs MI, HA, JA, DI SS, SR, MC, PA, GO, PC (common), Ds, PP, AA, MA, PH, TP (rare) DS, FF, Is

7 4.6/210 rubble area next to reef; loose Porites rubble on DI (abundant), HA, JA, PP CS, PP, DV, Tegula coarse sand SA, PA, DI, RH, VA, fasciata (rare) CO

8 3.4/240 cemented Porites porites rubble covered in brown; AM (abundant), DI, PA (abundant), CS, GO, RS (common), sediment is absent and dead shell material is rare HA, MI, PA, VA, CH, PP, Ms, AA, PC (rare) CO MA, Ss, Fs

9 4.3/270 hardground with a few pits; small burrowers make 2 SA, MI, DI, JA, HA, Ds, MI, Ms, PA, CS, BS (common), Ps, cm tall mounds of sand RH, CO MA, SS UH, Cerithium eburneum (rare)

10 6.1/300 rubble area at seaward edge of reef; rubble covered SA (common), PA, MI, PA, MA, SS, MI, CS, RS, Cerithium with green and brown turf PS, JA, DI, RI, PA, CO AA, PP eburneum, Cerithium litteratum, Ps (common), pectin scallop (rare)

Lindsay Reef (January 10-11, 2005) Depth (m)/ Live Hard Site Transect Description Algae Other Live Organisms Corals distance (m) 0 0/0 medium-size sand with no cobbles; this beach has no none none none beachrock near the water line

1 1.5/30 sandy, about 8 m from shoreline, sm. scale interference none none none ripples (4 cm); many shells and small coral debris

2 2.4/60 sandy with ripples (height: 25 cm; wavelength: 80 cm), none none CS, UH (rare) troughs are filled with coarse shell and coral debris

3 2.7/90 5 m from small reef; sandy with lg. scale ripples parallel to none none CA shore; little debris over 2 cm

3.5 1.5/108.9 18.9 m from site 3; depression in reef; scant live coral PA and DI SS, Ds, FF, YS, BA (common), UH, cover; mostly algal turf with a thin veneer of sediment (common), HA, PA, PP Ps, Cerithium UD, CH, MI, JA, eburneum(rare) SA

4 2.4/120 sandy, seaward side reef ridge; site extends under coral CH, MI, JA, TU PA Cs (abundant), CA, RS, ledge; shell debris concentrated directly under; sand has lg. BA (common) scale ripples

5 4.0/150 sandy site between two reef ridges; lg. scale ripples oriented none none CA (common) parallel to shore; Halimeda flakes in sediment

6 4.3/180 sandy site; two sand bodies meet; one older, with coarse none none DM, CA (common); DV, sand; newer sand body is fine and overriding the older one; UH (rare) where they meet there are plant debris, wood, and old gorgonians

7 4.3/210 coarse rippled sand about 1.5 m from reef; lg. scale ripples HA none DM, CA (common), DV, oriented perpendicular to reef and parallel to shore; troughs Ps (rare) are filled with shell and small coral rubble

8 4.6/225 sandy area at base of reef; rubble and dead coral heads HA, UD, DI, JA, AA, PP, PA, Ps (abundant), CS, YS, BA (Montastrea annularis ); coarse sand with Halimeda flakes SA, MI, LO, CH, SS, Es, Fs (common), Cerithium VA eburneum (rare)

Abbreviations: Live hard coral: EC = Echinometra Live alga: AA = Agaricia agaricites ES = Epinephelus striatus AC = Acetabularia DC = Diploria clivosa GO = Gorgonians AM = Amphiroa DS = Diploria strigosa HB = Halichoeres bivittatus (sp??) AV = Avrainvillia Ds = Dichocoenia sp. HF = Haemulon flavolineatum BA = Batophora Es = Eusmilia sp. HS = Haemulon sciurus CE = Ceramium FF = Favia fragum LS = Large sponge CH = Chaetomorpha Fs = Favia sp. MN = Melichthys niger CL = Cladophora Is = Isophylastrea sp. OR = Ophionereis reticulata CO = Other coralline algae MA = Montastrea annularis Os = Ophioderma sp. DA = Dasycladus MC = Montastrea cavernosa PC = Paguristes cadenati DI = Dictyota MF = Montastrea faviolata PG = Pseudopterogorgia sp. DS = Dictyosphaeria MI = Millipora sp. PH = Phimochirus holthusii GO = Goniolithon Ms = Manicina sp. Ps = Paguristes sp. GR = Other green algae MU = Mussa angulosa PL = Polinices lacteus HA = Halimeda PA = Porites astreoides PN = Platynereis JA = Jania PB = Porites branneri PO = Polychaete LA = Laurencia PP = Porites porites PP = Paguristes punticeps LI = Liagora Ps = Porites sp. Ps = Paguristes sp. LO = Lobophora SR = Siderastrea radians PU = Pencil urchin MI = Microdictyon SS = Siderastrea siderea RS = Red/orange encrusting sponges NE = Neomeris Ss = Scolymia sp. SA = Sabellid PA = Padina SP = Stegastes partitus PG = Pseudopterogoria Other live organisms: SS = Sargocentron spiniferum PS = Pseudoplexaura AC = Acanthurus chirugus SV = Sparisoma viride RH = Rhipocephalus BA = Briareum asbestinum TB = Thalassoma bifasciatum RI = Ricordea Bs = Briareum sp. TP = Teribellid polychaete SA = Sargassum BS = Black/brown sponges UH = Unknown hermit crab TU = Other turfs CN = Crassispira nigrescens US = Unidentified sponge UD = Udotea CA = Callianassa sp. YS = Yellow sponge VA = Valonia CC = Chromis cyanea ZO = Zoanthu CR = Caranx ruber Cs = Calsinnus sp. CS = Clionid sponges CT = Calcinnus tibescens DC = Decorator crab DI = Diadema sp. DM = Diatom mat Ds = Dardanus sp. DV = Dardanus venosis

APPENDIX B

MOLLUSCAN SUBSTRATE AFFINITIES

Molluscan taxa found in study that primarily live on soft substrates.

Soft-Bottom Molluscs

Gastropods Acteocina candei Haminoea sp. Persicula fluctuata Bulla striata Modulus modulus Pyramidella dolabrata Cerithidea scalariformis Nassarius albus Strombus sp. Enaeta cylleniformis Oliva sp. Triphora sp. Fasciolaria tulipa Olivella nivea

Bivalves Americardia guppyi Divaricella sp. Tellina fausta Americardia media Laevicardium laevigatum Tellina gouldii Cardiomya perrostrata Linga pensylvanica Tellina listeri Chione cancellata Lucina sp. Tellina magna Codakia costata Macoma sp. Tellina radiata Codakia orbicularis Papyridea soleniformis Tellina similis Codakia orbiculata Pinna sp. Tellina sp. Codakia sp. Pitar fulminatus Trachycardium magnum Cyrtopleura costata Semele sp. Transennella sp. Diplodonta semiaspera Strigilla sp.

Molluscan taxa found in study that primarily live on hard substrates.

Hardground Molluscs

Gastropods Acmaea spp.* Emarginula pumila Mitra nodulosa Arene riisei Engina turbinella Mitrella argus Calliostoma jujubinum Favartia alveata Morula nodulosa Capulus sp. Fissurella barbadensis* Morum oniscus Cerithium litteratum Fissurella sp. Nerita sp.* Cerithium spp. Fossarus orbignyi Nitidella nitida Cheilea equestris Heliacus bisulcatus Nodilittorina tuberculata* Cittarium pica Hemitoma emarginata Planaxis nucleus Colubraria lanceolata Hemitoma octoradiata Puncturella sp. Conus mus Hipponix antiquatus Puperita pupa* Conus regius Leucozonia ocellata Tectarius muricatus* Coralliophila abbreviata Littorina angustior* Tegula fasciata Coralliophila caribaea Littorina messpillum* Tegula lividomaculata Cyclostrema cancellatum Littorina nebulosa* Thais rustica* Diodora minuta Littorina ziczac* Tricolia bella Diodora sp. Lucapina sp. Turbo sp. Emarginula dentigera Mitra barbadensis

Bivalves Anomia simplex Brachidontes sp. Lima pellucida Arca sp. Caribachlamys imbricata Lima scabra Barbatia cancellaria Chama sp. Pinctada imbricata Barbatia candida Coralliophaga coralliophaga Plicatula gibbosa Barbatia domingensis Isognomon sp. Pododesmus sp. Barbatia tenera Lima lima Spondylus americanus Brachidontes domingensis

Others Chiton

* Molluscs known to live in intertidal ranges

Molluscan taxa found in study that primarily live around live coral. Molluscs Associated With Live Coral Gastropods Calliostoma jujubinum Coralliophila abbreviata Mitra barbadensis Conus mus Coralliophila caribaea Morum oniscus Conus regius Favartia alveata

Molluscan taxa found in study not associated with a substrate type.

Molluscs Not Affiliated With Substrate

Gastropods Anachis spp. Dolicholatirus cayohuesonicus Opalia sp. Arene cruentata Drillia sp. Petaloconchus sp. Astraea caelata Epitonium albidum Phalium granulatum Astraea phoebia Favartia cellulosa Philippia krebsii Astraea tecta Heliacus cylindricus Polinices lacteus Atlanta peronii Hyalina albolineata Pseudostomatella erythrocoma Atys caribaea Hyalina tenuilabra Pyrene ovulata Bailya intricata Kurtziella sp. Pyrene ovuloides Bailya parva Latirus A Pyrgocythara candidissima Cantharus lautus Latirus B Retusa bullata Cerion sp. Latirus infundibulum Risomurex rosea Cerithiopsis emersoni Latirus sp. Rissoina sp. Chicoreus sp. Litiopa melanostoma Seila adamsi Columbella mercatoria Mangelia sp. Siliquaria squamata Conus cardinalis Marginella sp. Terebra sp. Conus daucus Murex sp. Tonna sp. Conus jaspideus Muricidae A Tricolia sp. Conus spurius Nassarina minor Tripterotyphis triangularis Crassinella sp. Nassarina monolifera Trivia sp. Crassispira sp. Natica canrena Turbonilla sp. Cymatium sp. Natica livida* Turritella exoleta Cyphoma sp. Neodrillia cydia Vermicularia sp. Cypraea sp. Ocenebra emipowlusi Vexillum sp. Daphnella lymneiformis Ocenebra minirosea

Bivalves Arcopsis adamsi Glycymeris decussata Ischadium recurvum* Chlamys sp. Glycymeris pectinata Lyropecten antillarum Chione pygmaea Glycymeris undata Mysella sp.

Others Dentalium sp.

* Molluscs known to live in intertidal ranges

APPENDIX C

PERCENT OF MOLLUSCS BY SUBSTRATE PREFERENCE

% % % % % Substrate Month Site Abundance N/A HG Sand Intertidal Reef Lind-0 61 9.8 14.8 75.4 0.0 0.0 Snap-0 593 28.3 21.6 45.4 4.7 0.3 TP-0 372 27.2 21.0 48.4 3.5 0.3 January January Average 342 21.8 19.1 56.4 2.7 0.2 Lind-0 25 0.0 16.0 76.0 8.0 0.0

Beach sites Beach Snap-0 895 32.5 26.6 28.9 12.0 0.2

June June TP-0 304 23.4 29.6 31.6 15.5 2.0 Average 408 18.6 24.1 45.5 11.8 0.7 Snap-1 42 33.3 26.2 40.5 0.0 2.4 Snap-2 46 15.2 23.9 60.9 0.0 2.2 Snap-3 43 32.6 2.3 65.1 0.0 0.0 Snap-4 66 34.8 16.7 48.5 0.0 1.5 Snap-5 58 44.8 15.5 37.9 1.7 0.0 Snap-6 71 36.6 18.3 45.1 0.0 1.4 Snap-8 72 26.4 13.9 59.7 0.0 0.0 TP-1 69 34.8 21.7 43.5 0.0 1.4 January January TP-2 16 50.0 18.8 31.3 0.0 0.0 TP-3 38 50.0 21.1 28.9 0.0 0.0 TP-5 47 40.4 23.4 36.2 0.0 0.0 TP-8 2 100.0 0.0 0.0 0.0 0.0 TP-9 39 35.9 30.8 33.3 0.0 2.6 Average 47 41.1 17.9 40.8 0.1 0.9 Snap-1 53 35.8 22.6 41.5 0.0 0.0

Hardground Sites Hardground Snap-2 123 52.8 13.0 34.1 0.0 0.0 Snap-3 34 47.1 17.6 35.3 0.0 0.0 Snap-4 49 26.5 26.5 46.9 0.0 4.1 Snap-5 39 48.7 17.9 33.3 0.0 0.0 Snap-6 35 37.1 0.0 62.9 0.0 0.0

June June Snap-7 74 25.7 12.2 60.8 1.4 0.0 TP-1 13 30.8 7.7 53.8 7.7 0.0 TP-2 10 30.0 30.0 40.0 0.0 0.0 TP-3 25 52.0 8.0 40.0 0.0 0.0 TP-5 68 22.1 36.8 39.7 1.5 0.0 Average 48 37.1 17.5 44.4 1.0 0.4

% % % % % Substrate Month Site Abundance N/A HG Sand Intertidal Reef Lind-1 107 24.3 37.4 35.5 2.8 2.8 Lind-2 2125 55.7 17.6 25.9 0.8 0.9 Lind-3 17 35.3 17.6 47.1 0.0 5.9 Lind-5 73 35.6 21.9 41.1 1.4 2.7 Lind-6 140 41.4 19.3 38.6 0.7 0.7 January January Lind-7 740 41.1 35.0 23.8 0.1 1.5 TP-4 145 32.4 19.3 48.3 0.0 0.7 Average 478 38.0 24.0 37.2 0.8 2.2 Lind-1 177 17.5 30.5 46.3 5.6 0.6 Lind-2 57 8.8 19.3 71.9 0.0 0.0 Sand Sites Lind-6 7 28.6 14.3 57.1 0.0 0.0 Lind-7 20 30.0 15.0 55.0 0.0 5.0 Lind-8 153 39.2 25.5 35.3 0.0 1.3 June June Lind-9 2342 20.3 26.0 53.5 0.2 0.3 Lind-10 94 22.3 50.0 27.7 0.0 0.0 TP-4 159 24.5 16.4 59.1 0.0 0.0 Average 376 23.9 24.6 50.7 0.7 0.9 Lind-3.5 222 45.5 41.4 12.2 0.9 2.3 Lind-4 1291 55.3 16.0 28.0 0.7 1.2 Lind-8 682 20.7 48.5 28.7 2.1 1.3 Snap-9 73 38.4 20.5 41.1 0.0 0.0 Snap-10 76 26.3 26.3 47.4 0.0 1.3

January January TP-6 125 24.0 39.2 36.0 0.8 0.0 TP-7 147 40.8 44.9 14.3 0.0 0.7 TP-10 87 40.2 25.3 34.5 0.0 1.1 Average 338 36.4 32.8 30.3 0.6 1.0 Lind-3 29 24.1 51.7 24.1 0.0 0.0 Lind-4 47 31.9 44.7 21.3 2.1 2.1 Lind-5 8 0.0 0.0 100.0 0.0 0.0 Reef Sites Reef Lind-11 115 20.9 59.1 20.0 0.0 1.7 Snap-8 61 32.8 23.0 44.3 0.0 1.6 Snap-9 34 23.5 26.5 50.0 0.0 0.0

June June TP-6 73 28.8 34.2 37.0 0.0 0.0 TP-7 54 33.3 29.6 37.0 0.0 0.0 TP-8 7 57.1 14.3 28.6 0.0 0.0 TP-9 22 31.8 45.5 22.7 0.0 0.0 TP-10 72 25.0 31.9 43.1 0.0 1.4 Average 48 28.1 32.8 38.9 0.2 0.6

APPENDIX D

MOLLUSC COUNTS

January dead mollusc counts only including 22 most abundant taxa.

June dead mollusc counts only including 22 most abundant taxa.

Additional taxa and their abundances for January samples:

JanSnap-0: Acmaea pustulata 2; Acmaea spp. 3; Acteocina candei 2; Americardia media 1; Anachis spp. 3; Arca sp. 5; Arcopsis adamsi 2; Bailya parva 1; Barbatia candida 1; Brachidontes domingensis 3; Calliostoma jujubinum 1; Cerion sp. 1; Chama sp. 6; Cheilea equestris 1; Chione pygmaea 10; Chiton 1; Codakia costata 1; Codakia orbiculata 1; Colubraria lanceolata 1; Crassispira sp. 1; Cymatium sp. 2; Cypraea sp. 2; Dentalium sp. 3; Diodora minuta 8; Diodora sp. 2; Fissurella barbadensis 11; Glycymeris decussata 2; Glycymeris undata 2; Hemitoma octoradiata 1; Kurtziella sp. 2; Laevicardium laevigatum 2; Lima lima 1; Lima pellucida 1; Lima scabra 1; Litiopa melanostoma 1; Littorina mespillum 1; Littorina ziczac 2; Marginella sp. 1; Mitra nodulosa 1; Morum oniscus 1; Muricidae A 1; Nassarius albus 5; Nerita sp. 11; Nitidella nitida 1; Petaloconchus sp. 3; Phalium granulatum 1; Pitar fulminatus 2; Risomure rosea 1; Rissoina sp. 1; Strigilla sp. 8; Tegula lividomaculata 4; Tellina gouldii 1; Tellina listeri 1; Terebra sp. 2; Turbonilla sp. 1

JanSnap-1: Acmaea pustulata 1; Cheilea equestris 1; Cittarium pica 1; Codakia orbiculata 1; Dentalium sp. 1; Laevicardium laevigatum 2; Lima pellucida 1; Lima scabra 1; Lucapina sp. 1; Morum oniscus 1; Tellina fausta 1

JanSnap-2: Arcopsis adamsi 1; Cerion sp. 1; Chione pygmaea 2; Coralliophila caribaea 1; Glycymeris undata 1; Lima scabra 1; Mitra nodulosa 1; Strigilla sp. 1; Tegula lividomaculata 1

JanSnap-3: Codakia costata 1; Codakia orbicularis 1; Dentalium sp. 1

JanSnap-4: Chione pygmaea 3; Codakia orbicularis 2; Lima lima 1; Lima scabra 1; Mitra barbadensis 1; Phalium granulatum 1; Semele sp. 1

JanSnap-5: Astraea phoebia 1; Chione pygmaea 1; Conus spurius 1; Cymatium sp. 2; Dentalium sp. 3; Fasciolaria tulipa 1; Fissurella barbadensis 1; Nassarius albus 1; Spondylus americanus 1; Strigilla sp. 1; Tellina listeri 1

JanSnap-6: Calliostoma jujubinum 1; Chlamys sp. 1; Codakia costata 1; Dentalium sp. 1; Diodora minuta 1; Laevicardium laevigatum 2; Mitra nodulosa 1; Mysella sp. 1; Nassarius albus 1; Semele sp. 1; Strigilla sp. 1; Tegula lividomaculata 1; Trivia sp. 1; Veillum sp. 1

JanSnap-8: Anachis spp. 1; Arcopsis adamsi 1; Chama sp. 1; Chione pygmaea 1; Codakia costata 1; Cymatium sp. 2; Cyphoma sp. 1; Dentalium sp. 1; Laevicardium laevigatum 1; Mitra nodulosa 1; Phalium granulatum 1; Pitar fulminatus 1; Strigilla sp. 2; Tellina listeri 1; Terebra sp. 1

JanSnap-9: Acmaea pustulata 1; Arcopsis adamsi 3; Cheilea equestris 1; Codakia costata 1; Cymatium sp. 1; Diodora sp. 1; Fasciolaria tulipa 1; Glycymeris decussata 1; Glycymeris undata 1; Kurtziella sp. 1; Laevicardium laevigatum 3; Lima scabra 1; Pitar fulminatus 1; Semele sp. 1; Strigilla sp. 1; Tegula lividomaculata 1; Veillum sp. 2

JanSnap-10: Americardia media 1; Arca sp. 1; Astraea caelata 1; Astraea phoebia 1; Calliostoma jujubinum 1; Chama sp. 3; Chlamys sp. 1; Cymatium sp. 1; Dentalium sp. 1; Emarginula pumila 1; Fasciolaria tulipa 1; Glycymeris decussata 1; Laevicardium laevigatum 1; Lima scabra 2; Petaloconchus sp. 2; Phalium granulatum 1; Pododesmus sp. 1; Semele sp. 1; Tellina fausta 1; Tellina gouldii 1; Tellina listeri 2

JanTP-0: Acmaea spp. 5; Acteocina candei 2; Arca sp. 2; Arcopsis adamsi 2; Astraea phoebia 1; Cerion sp. 2; Chama sp. 5; Cheilea equestris 1; Chione pygmaea 3; Chiton 2; Chlamys sp. 1; Cittarium pica 1; Codakia costata 1; Codakia orbicularis 1; Crassispira sp. 3; Cyphoma sp. 1; Dentalium sp. 3; Diodora minuta 4; Fissurella barbadensis 2; Glycymeris decussata 1; Glycymeris undata 1; Lima pellucida 1; Littorina ziczac 3; Mitra barbadensis 1; Mitra nodulosa 4; Morula nodulosa 1; Neodrillia cydia 5; Nerita sp. 2; Plicatula gibbosa 1; Puperita pupa 1; Rissoina sp. 1; Tellina gouldii 1; Terebra sp. 3; Veillum sp. 3

JanTP-1: Acmaea pustulata 1; Brachidontes domingensis 1; Codakia orbicularis 3; Cymatium sp. 1; Dentalium sp. 1; Fasciolaria tulipa 1; Glycymeris decussata 1; Glycymeris undata 1; Hemitoma octoradiata 1; Laevicardium laevigatum 1; Mitra nodulosa 1; Morum oniscus 1; Nassarius albus 2; Neodrillia cydia 1; Strigilla sp. 2; Tegula lividomaculata 1; Tellina listeri 1

JanTP-2: Cypraea sp. 2

JanTP-3: Anachis spp. 1; Codakia orbicularis 1; Cymatium sp. 1; Dentalium sp. 1; Laevicardium laevigatum 1; Lima scabra 1; Macoma sp. 1; Nassarius albus 1; Tegula lividomaculata 1

JanTP-4: Acmaea pustulata 1; Americardia media 1; Anachis spp. 3; Arca sp. 1; Arcopsis adamsi 2; Astraea phoebia 1; Brachidontes domingensis 1; Cheilea equestris 2; Chione pygmaea 1; Chlamys sp. 1; Codakia costata 1; Codakia orbiculata 1; Cymatium sp. 2; Dentalium sp. 6; Kurtziella sp. 2; Laevicardium laevigatum 1; Lima pellucida 1; Lima scabra 2; Lucina sp. 1; Lyropecten antillarum 1; Mitra barbadensis 1; Nassarius albus 1; Pinna sp. 1; Plicatula gibbosa 1; Rissoina sp. 1; Strigilla sp. 1; Tegula lividomaculata 1; Tellina gouldii 3; Tellina listeri 4; Tellina similis 1; Triphora sp. 1

JanTP-5: Acmaea pustulata 1; Brachidontes domingensis 1; Chama sp. 1; Codakia orbiculata 1; Cymatium sp. 1; Cyphoma sp. 1; Dentalium sp. 1; Nassarius albus 1; Tellina listeri 1

JanTP-6: Americardia media 1; Arca sp. 4; Arcopsis adamsi 2; Arene cruentata 1; Bailya intricata 1; Chiton 1; Chlamys sp. 1; Codakia orbicularis 1; Codakia orbiculata 4; Cyphoma sp. 1; Cypraea sp. 1; Dentalium sp. 2; Diodora sp. 1; Emarginula pumila 3; Fasciolaria tulipa 1; Laevicardium laevigatum 1; Latirus A 1; Lima pellucida 1; Lima scabra 1; Littorina nebulosa 1; Macoma sp. 1; Mitra nodulosa 1; Nassarius albus 1; Papyridea soleniformis 1; Petaloconchus sp. 2; Pyrene ovulata 1; Strigilla sp. 1; Tegula lividomaculata 1; Tellina gouldii 2; Tellina listeri 2; Tellina similis 2; Tellina sp. 1; Trivia sp. 1

JanTP-7: Acmaea pustulata 3; Arcopsis adamsi 1; Arene riisei 2; Chama sp. 2; Cheilea equestris 3; Chlamys sp. 2; Codakia orbiculata 1; Conus mus 1; Cyphoma sp. 1; Cypraea sp. 2; Daphnella lymneiformis 4; Dentalium sp. 4; Diodora sp. 1; Emarginula pumila 2; Haminoea sp. 1; Laevicardium laevigatum 3; Lima lima 1; Lima pellucida 2; Lima scabra 4; Nassarius albus 1; Papyridea soleniformis 1; Retusa bullata 1; Rissoina sp. 1; Siliquaria squamata 1; Tegula lividomaculata 5; Tellina gouldii 1; Tellina listeri 1; Trivia sp. 2; Veillum sp. 1

JanTP-8: No additional taxa

JanTP-9: Americardia media 1; Arca sp. 2; Arcopsis adamsi 1; Barbatia candida 1; Cheilea equestris 1; Codakia orbicularis 1; Codakia orbiculata 1; Coralliophila caribaea 1; Lima scabra 2; Mure sp. 1; Nassarius albus 1; Phalium granulatum 1; Tegula lividomaculata 1; Tellina listeri 1

JanTP-10: Americardia media 1; Arcopsis adamsi 2; Astraea caelata 1; Barbatia candida 1; Chama sp. 1; Cheilea equestris 1; Chlamys sp. 1; Codakia costata 2; Codakia orbicularis 4; Codakia orbiculata 1; Conus daucus 1; Coralliophila caribaea 1; Cymatium sp. 1; Cyphoma sp. 1; Cypraea sp. 1; Dentalium sp. 1; Diodora sp. 1; Enaeta cylleniformis 1; Fasciolaria tulipa 2; Laevicardium laevigatum 2; Lima scabra 1; Mure sp. 1; Phalium granulatum 1; Pyrene ovulata 1; Tellina listeri 1

JanLind-0: Americardia media 1; Arca sp. 1; Brachidontes domingensis 1; Capulus sp. 1; Chione pygmaea 2; Dentalium sp. 1; Diodora minuta 1; Laevicardium laevigatum 1; Lima scabra 2; Nitidella nitida 1; Phalium granulatum 1; Strigilla sp. 4; Tellina gouldii 1

JanLind-1: Acmaea pustulata 1; Arca sp. 2; Arcopsis adamsi 1; Calliostoma jujubinum 2; Chama sp. 1; Chione pygmaea 1; Chiton 1; Codakia costata 1; Cypraea sp. 1; Dentalium sp. 1; Engina turbinella 1; Heliacus cylindricus 1; Latirus infundibulum 1; Morum oniscus 1; Nerita sp. 2; Petaloconchus sp. 1; Tellina listeri 1; Thais rustica 1

JanLind-2: Acteocina candei 12; Anachis spp. 9; Arca sp. 17; Arcopsis adamsi 6; Arene cruentata 4; Astraea caelata 2; Astraea phoebia 2; Bailya parva 1; Brachidontes domingensis 1; Brachidontes sp. 1; Calliostoma jujubinum 3; Cerion sp. 1; Cerithidea scalariformis 1; Chama sp. 5; Cheilea equestris 4; Chione pygmaea 2; Cittarium pica 2; Codakia costata 1; Conus cardinalis 1; Coralliophila abbreviata 1; Coralliophila caribaea 3; Crassispira sp. 6; Cymatium sp. 12; Cypraea sp. 4; Dentalium sp. 6; Diodora minuta 4; Diodora sp. 1; Dolicholatirus cayohuesonicus 2; Emarginula pumila 1; Engina turbinella 4; Fasciolaria tulipa 3; Favartia alveata 1; Favartia cellulosa 4; Glycymeris decussata 1; Heliacus cylindricus 3; Hyalina albolineata 2; Hyalina tenuilabra 1; Kurtziella sp. 10; Latirus infundibulum 1; Lima scabra 2; Littorina mespillum 2; Littorina nebulosa 1; Littorina ziczac 1; Lucina sp. 1; Mangelia sp. 1; Marginella sp. 1; Mitra barbadensis 7; Morula nodulosa 2; Morum oniscus 5; Mure sp. 3; Nassarina minor 2; Nassarina monolifera 1; Nassarius albus 24; Natica canrena 27; Natica livida 5; Nerita sp. 3; Nodilittorina tuberculata 2; Opalia sp. 1; Persicula fluctuata 5; Petaloconchus sp. 18; Pitar fulminatus 1; Plicatula gibbosa 1; Puncturella sp. 1; Puperita pupa 1; Pyramidella dolabrata 1; Pyrene ovulata 5; Retusa bullata 1; Risomure rosea 4; Rissoina sp. 8; Siliquaria squamata 1; Strigilla sp. 2; Tectarius muricatus 1; Tegula lividomaculata 5; Tellina gouldii 1; Trachycardium magnum 1; Tricolia bella 1; Triphora sp. 1; Trivia sp. 2; Turbo sp. 1; Turbonilla sp. 2; Vermicularia sp. 1; Veillum sp. 6

JanLind-3: Calliostoma jujubinum 1; Mure sp. 1; Strigilla sp. 1

JanLind-3 5: Acmaea pustulata 1; Acteocina candei 1; Anachis spp. 2; Arca sp. 3; Arcopsis adamsi 1; Atlanta peronii 1; Chama sp. 1; Cheilea equestris 1; Chione pygmaea 1; Codakia sp. 3; Conus mus 1; Cymatium sp. 3; Cypraea sp. 1; Dentalium sp. 11; Diodora minuta 2; Fasciolaria tulipa 1; Isognomon sp. 1; Lima scabra 2; Litiopa melanostoma 1; Littorina nebulosa 2; Mitra barbadensis 1; Morula nodulosa 1; Morum oniscus 3; Natica canrena 1; Strigilla sp. 1; Tegula lividomaculata 1; Tellina similis 1; Trivia sp. 1; Turbo sp. 2; Vermicularia sp. 1; Veillum sp. 1

JanLind-4: Acmaea spp. 2; Acteocina candei 9; Arca sp. 7; Arcopsis adamsi 1; Arene cruentata 3; Astraea phoebia 2; Bailya intricata 1; Calliostoma jujubinum 3; Cerion sp. 2; Cerithidea scalariformis 1; Cheilea equestris 1; Chiton 1; Codakia orbicularis 1; Colubraria lanceolata 1; Coralliophila caribaea 2; Cymatium sp. 3; Cypraea sp. 1; Daphnella lymneiformis 25; Dentalium sp. 9; Diodora minuta 1; Drillia sp. 1; Emarginula pumila 2; Enaeta cylleniformis 1; Engina turbinella 2; Favartia cellulosa 2; Haminoea sp. 2; Heliacus cylindricus 1; Hyalina albolineata 4; Kurtziella sp. 9; Latirus A 2; Latirus infundibulum 1; Latirus sp. 1; Litiopa melanostoma 1; Lucina sp. 1; Mitra barbadensis 4; Morum oniscus 7; Nassarius albus 23; Natica canrena 21; Natica livida 7; Ocenebra minirosea 1; Opalia sp. 3; Persicula fluctuata 6; Petaloconchus sp. 11; Phalium granulatum 2; Plicatula gibbosa 1; Pyrene ovulata 2; Pyrene ovuloides 2; Pyrgocythara candidissima 1; Rissoina sp. 3; Siliquaria squamata 2; Strigilla sp. 4; Tegula lividomaculata 6; Tellina similis 3; Terebra sp. 1; Triphora sp. 1; Tripterotyphis triangularis 1; Trivia sp. 2; Turbo sp. 3; Turbonilla sp. 1; Vermicularia sp. 1

JanLind-5: Acteocina candei 1; Anachis spp. 1; Arca sp. 1; Arcopsis adamsi 1; Cymatium sp. 2; Dentalium sp. 1; Favartia alveata 1; Morum oniscus 1; Nassarius albus 3; Natica canrena 2; Natica livida 1; Petaloconchus sp. 1; Tellina similis 1; Trivia sp. 1

JanLind-6: Acteocina candei 1; Arca sp. 2; Astraea phoebia 1; Bailya parva 1; Calliostoma jujubinum 1; Cerion sp. 3; Codakia orbicularis 1; Cymatium sp. 1; Cypraea sp. 1; Daphnella lymneiformis 4; Diodora sp. 1; Fasciolaria tulipa 1; Favartia cellulosa 1; Haminoea sp. 2; Isognomon sp. 1; Kurtziella sp. 1; Lima scabra 1; Littorina ziczac 1; Marginella sp. 1; Nassarius albus 3; Petaloconchus sp. 1; Phalium granulatum 1; Strigilla sp. 3; Tonna sp. 2; Tricolia bella 1; Triphora sp. 1; Tripterotyphis triangularis 1; Turbonilla sp. 2

JanLind-7: Acteocina candei 4; Anachis spp. 2; Anomia simple 1; Arca sp. 2; Arcopsis adamsi 4; Astraea phoebia 3; Atlanta peronii 1; Bailya intricata 1; Barbatia candida 2; Capulus sp. 1; Cerithiopsis emersoni 1; Chama sp. 6; Colubraria lanceolata 2; Conus mus 2; Crassinella sp. 1; Crassispira sp. 2; Cymatium sp. 5; Cyrtopleura costata 1; Daphnella lymneiformis 15; Dentalium sp. 9; Diodora minuta 2; Emarginula pumila 2; Engina turbinella 4; Glycymeris decussata 1; Heliacus bisulcatus 1; Hyalina albolineata 2; Kurtziella sp. 4; Latirus infundibulum 1; Littorina nebulosa 1; Lucina sp. 3; Marginella sp. 2; Mitra barbadensis 9; Morula nodulosa 3; Nassarina minor 1; Nassarina monolifera 2; Nassarius albus 2; Natica canrena 5; Ocenebra minirosea 1; Persicula fluctuata 1; Petaloconchus sp. 5; Plicatula gibbosa 2; Pyrene ovuloides 9; Risomure rosea 8; Rissoina sp. 8; Seila adamsi 1; Semele sp. 1; Siliquaria squamata 1; Tegula lividomaculata 2; Tellina gouldii 2; Tellina listeri 2; Triphora sp. 3; Tripterotyphis triangularis 1; Trivia sp. 1; Turbo sp. 1; Turbonilla sp. 1; Turritella eoleta 11; Veillum sp. 1

JanLind-8: Acmaea spp. 3; Anachis spp. 2; Arca sp. 6; Arcopsis adamsi 1; Astraea caelata 2; Atys caribaea 1; Bailya intricata 1; Barbatia candida 4; Brachidontes sp. 1; Calliostoma jujubinum 1; Cardiomya perrostrata 1; Chama sp. 9; Cheilea equestris 3; Chione pygmaea 2; Chiton 2; Chlamys sp. 1; Codakia costata 3; Codakia orbicularis 6; Codakia orbiculata 3; Conus mus 1; Conus regius 1; Coralliophila caribaea 1; Crassispira sp. 2; Cymatium sp. 4; Cyphoma sp. 2; Cyrtopleura costata 1; Daphnella lymneiformis 5; Dentalium sp. 9; Diodora minuta 4; Diodora sp. 4; Emarginula pumila 3; Engina turbinella 1; Favartia cellulosa 1; Fissurella barbadensis 5; Haminoea sp. 2; Isognomon sp. 1; Laevicardium laevigatum 1; Latirus infundibulum 1; Leucozonia ocellata 1; Lima scabra 14; Littorina nebulosa 4; Lucapina sp. 1; Lucina sp. 2; Marginella sp. 2; Mitra barbadensis 3; Morula nodulosa 1; Morum oniscus 2; Mure sp. 1; Nassarius albus 3; Natica canrena 4; Persicula fluctuata 1; Petaloconchus sp. 2; Plicatula gibbosa 2; Pyrene ovuloides 5; Risomure rosea 1; Rissoina sp. 1; Siliquaria squamata 1; Spondylus americanus 1; Strigilla sp. 3; Tellina fausta 6; Tellina listeri 3; Tellina similis 6; Thais rustica 2; Triphora sp. 1; Trivia sp. 1; Turbo sp. 3; Turritella eoleta 3; Vermicularia sp. 1; Veillum sp. 3

Additional taxa and their abundances for June samples:

JunSnap-0: Acmaea spp. 35; Acteocina candei 1; Arca sp. 9; Arcopsis adamsi 8; Arene cruentata 1; Astraea phoebia 1; Barbatia candida 1; Brachidontes domingensis 15; Chama sp. 7; Cheilea equestris 1; Chione pygmaea 3; Chiton 3; Chlamys sp. 1; Cittarium pica 1; Codakia costata 1; Codakia orbiculata 1; Conus mus 1; Cymatium sp. 5; Cypraea sp. 3; Diodora minuta 6; Diodora sp. 5; Emarginula pumila 3; Favartia cellulosa 2; Fissurella barbadensis 28; Glycymeris decussata 1; Glycymeris undata 2; Hemitoma octoradiata 1; Isognomon sp. 1; Latirus A 1; Lima lima 1; Lima pellucida 1; Littorina angustior 3; Littorina ziczac 3; Lucina sp. 2; Mitra nodulosa 3; Mitrella argus 2; Morula nodulosa 2; Morum oniscus 1; Nassarius albus 2; Natica livida 2; Nerita sp. 28; Nitidella nitida 3; Nodilittorina tuberculata 6; Petaloconchus sp. 5; Phalium granulatum 1; Philippia krebsii 1; Planaxis nucleus 1; Plicatula gibbosa 2; Puperita pupa 2; Pyramidella dolabrata 1; Strigilla sp. 2; Tegula lividomaculata 3; Tellina gouldii 1; Terebra sp. 1; Vexillum sp. 2

JunSnap-1: Arcopsis adamsi 1; Chama sp. 1; Chione pygmaea 3; Codakia orbicularis 1; Cymatium sp. 1; Dentalium sp. 2; Laevicardium laevigatum 1; Lima scabra 1; Phalium granulatum 1; Plicatula gibbosa 1; Tegula lividomaculata 1; Tellina gouldii 2

JunSnap-2: Arca sp. 1; Chama sp. 1; Codakia orbicularis 4; Hemitoma octoradiata 1; Laevicardium laevigatum 2; Lima scabra 1; Nassarius albus 2; Semele sp. 1; Strigilla sp. 1; Tegula lividomaculata 1; Tellina gouldii 1; Tellina listeri 1; Tellina magna 1; Trivia sp. 1; Vexillum sp. 1

JunSnap-3: Arcopsis adamsi 1; Chione pygmaea 1; Dentalium sp. 1

JunSnap-4: Anachis spp. 1; Astraea caelata 1; Chama sp. 1; Chione pygmaea 1; Codakia orbicularis 2; Conus mus 1; Conus spurius 1; Dentalium sp. 1; Hemitoma octoradiata 1; Mitra barbadensis 1; Mitra nodulosa 1; Nassarius albus 1; Terebra sp. 1

JunSnap-5: Chione pygmaea 2; Cymatium sp. 1; Dentalium sp. 1; Laevicardium laevigatum 1; Lyropecten antillarum 1; Pinna sp. 1; Pitar fulminatus 1; Tellina gouldii 1

JunSnap-6: Americardia media 1; Chione pygmaea 1; Dentalium sp. 1; Glycymeris undata 2; Lucina sp. 1; Pinna sp. 1

JunSnap-7: Acmaea spp. 1; Codakia costata 1; Cypraea sp. 1; Dentalium sp. 1; Fasciolaria tulipa 1; Laevicardium laevigatum 1; Lima scabra 1; Morula nodulosa 1; Nassarius albus 1; Strigilla sp. 1; Tellina gouldii 1; Tellina magna 1

JunSnap-8: Arca sp. 1; Arcopsis adamsi 1; Bailya intricata 1; Chama sp. 1; Cittarium pica 1; Cyphoma sp. 1; Cypraea sp. 2; Lima pellucida 1; Lima scabra 1; Lucapina sp.1; Mitra barbadensis 1; Phalium granulatum 1; Tellina magna 3; Tonna sp. 1

JunSnap-9: Brachidontes domingensis 2; Brachidontes sp. 1; Cittarium pica 1; Codakia orbiculata 1; Cymatium sp. 1; Laevicardium laevigatum 2; Lima scabra 1; Lucapina sp.1; Nassarius albus 1; Strigilla sp. 1; Tellina gouldii 1; Tellina listeri 1; Vermicularia sp. 1; Vexillum sp. 1

JunTP-0: Acmaea pustulata 3; Acmaea spp. 14; Arca sp. 6; Arcopsis adamsi 1; Calliostoma jujubinum 1; Cerion sp. 1; Chama sp. 5; Chione pygmaea 2; Chiton 2; Cittarium pica 1; Codakia orbicularis 1; Codakia orbiculata 2; Cymatium sp. 2; Cypraea sp. 2; Dentalium sp. 1; Diodora minuta 1; Diodora sp. 1; Fasciolaria tulipa 1; Fissurella barbadensis 16; Glycymeris decussata 2; Glycymeris undata 3; Hemitoma octoradiata 1; Latirus A 1; Lima lima 1; Lucapina sp.2; Mitra barbadensis 1; Mitra nodulosa 2; Morum oniscus 4; Nerita sp. 14; Nodilittorina tuberculata 2; Oliva sp. 1; Petaloconchus sp. 1; Phalium granulatum 1; Puperita pupa 1; Pyramidella dolabrata 1; Rissoina sp. 1; Tegula lividomaculata 1; Tellina gouldii 1; Tellina listeri 1; Terebra sp. 1

JunTP-1: Codakia orbicularis 1; Fissurella barbadensis 1; Lucina sp. 1

JunTP-2: Chione pygmaea 1; Laevicardium laevigatum 2; Pinctada imbricata 1

JunTP-3: Anachis spp. 1; Cymatium sp. 2; Dentalium sp. 2; Epitonium albidum 1; Glycymeris undata 1; Nassarius albus 1; Petaloconchus sp. 1

JunTP-4: Acmaea pustulata 1; Arca sp. 3; Arcopsis adamsi 1; Brachidontes domingensis 1; Chama sp. 2; Chlamys sp. 1; Codakia orbicularis 2; Codakia orbiculata 2; Codakia sp. 1; Cyphoma sp. 1; Dentalium sp. 5; Diplodonta semiaspera 2; Dolicholatirus cayohuesonicus 1; Glycymeris undata 1; Kurtziella sp. 1; Laevicardium laevigatum 4; Lima scabra 2; Nassarius albus 2; Phalium granulatum 1; Plicatula gibbosa 2; Rissoina sp. 1; Strigilla sp. 4; Tegula lividomaculata 1; Tellina fausta 1; Tellina gouldii 1; Tellina listeri 4; Tellina similis 3; Terebra sp. 1

JunTP-5: Americardia media 2; Arca sp. 2; Brachidontes domingensis 2; Cantharus lautus 1; Chama sp. 2; Chicoreus sp. 1; Cypraea sp. 1; Dentalium sp. 1; Dolicholatirus cayohuesonicus 1; Fissurella barbadensis 1; Lima pellucida 2; Lima scabra 1; Nassarius albus 1; Spondylus americanus 1; Tellina fausta 1; Tellina listeri 2; Tellina similis 1; Tellina sp. 1; Turbo sp. 1

JunTP-6: Americardia media 1; Arca sp. 1; Astraea caelata 1; Chama sp. 1; Cheilea equestris 2; Codakia costata 2; Crassispira sp. 1; Cyphoma sp. 2; Emarginula pumila 2; Laevicardium laevigatum 1; Lima pellucida 1; Lucina sp. 1; Petaloconchus sp. 1; Pinna sp. 1; Tegula lividomaculata 1; Tellina fausta 1; Tellina gouldii 3; Tellina listeri 2; Tellina similis 1; Tellina sp. 1; Trivia sp. 2

JunTP-7: Acmaea pustulata 2; Americardia media 1; Chama sp. 1; Cheilea equestris 1; Codakia orbicularis 3; Cypraea sp. 1; Daphnella lymneiformis 1; Dentalium sp. 3; Emarginula pumila 2; Haminoea sp. 1; Laevicardium laevigatum 2; Latirus B 1; Lima scabra 1; Lucina sp. 1; Mysella sp. 1; Strigilla sp. 1; Tegula lividomaculata 1; Tellina fausta 1; Tellina gouldii 1; Tellina listeri 2; Tellina similis 1; Tonna sp. 1; Triphora sp. 1; Trivia sp. 1

JunTP-8: Mitra nodulosa 1; Papyridea soleniformis 1

JunTP-9: Astraea caelata 1; Chama sp. 1; Dentalium sp. 1; Hemitoma octoradiata 1; Lima pellucida 1; Tegula lividomaculata 1

JunTP-10: Acmaea pustulata 1; Americardia media 2; Anachis spp. 1; Arcopsis adamsi 1; Calliostoma jujubinum 1; Chama sp. 3; Chlamys sp. 3; Codakia costata 2; Codakia orbicularis 2; Codakia orbiculata 2; Cyphoma sp. 1; Cypraea sp. 1; Diodora sp. 1; Hemitoma octoradiata 1; Hyalina albolineata 1; Laevicardium laevigatum 1; Lima scabra 2; Lucina sp. 1; Lyropecten antillarum 1; Mitra nodulosa 1; Petaloconchus sp. 1; Tegula lividomaculata 1; Tellina gouldii 1; Tellina listeri 2; Tellina similis 1; Trivia sp. 1

JunLind-0: Acmaea spp. 2; Chlamys sp. 1; Lucina sp. 1; Strigilla sp. 2

JunLind-1: Acmaea spp. 2; Acteocina candei 1; Calliostoma jujubinum 1; Caribachlamys imbricata 1; Chama sp. 3; Chione pygmaea 1; Codakia orbicularis 1; Codakia orbiculata 1; Cymatium sp. 4; Dentalium sp. 1; Fissurella barbadensis 4; Glycymeris undata 2; Hemitoma emarginata 1; Hemitoma octoradiata 2; Kurtziella sp. 1; Laevicardium laevigatum 1; Latirus infundibulum 1; Lima pellucida 1; Lima scabra 1; Littorina ziczac 1; Lucina sp. 1; Nassarius albus 1; Nerita sp. 2; Nodilittorina tuberculata 1; Petaloconchus sp. 2; Pyrene ovulata 1; Strigilla sp. 1; Tegula lividomaculata 1; Terebra sp. 1

JunLind-2: Codakia orbicularis 1; Diodora minuta 1; Emarginula pumila 1; Laevicardium laevigatum 1; Lima scabra 1; Strigilla sp. 2; Tellina similis 1

JunLind-3: Astraea caelata 1; Coralliophaga coralliophaga 1; Cymatium sp. 1; Favartia cellulosa 1; Tegula lividomaculata 1

JunLind-4: Chama sp. 1; Cittarium pica 1; Cymatium sp. 2; Littorina angustior 1; Macoma sp. 1; Morum oniscus 1; Risomurex rosea 1; Turbo sp. 1; Turritella exoleta 1; Vermicularia sp. 1

JunLind-5: Lucina sp. 1; Strigilla sp. 2; Tellina similis 1

JunLind-6: Chiton 1; Strigilla sp. 2; Tellina similis 1

JunLind-7: Arca sp. 1; Calliostoma jujubinum 1; Lucapina sp.1; Papyridea soleniformis 1; Petaloconchus sp. 1; Strigilla sp. 4; Tellina similis 1

JunLind-8: Acteocina candei 1; Anachis spp. 3; Arca sp. 3; Conus regius 1; Dentalium sp. 3; Fossarus orbignyi 1; Kurtziella sp. 1; Lima scabra 2; Lucina sp. 1; Mitra barbadensis 1; Natica canrena 1; Risomurex rosea 1; Rissoina sp. 8; Strigilla sp. 2; Tellina gouldii 3; Tellina magna 1; Tellina sp. 1; Terebra sp. 1; Tonna sp. 1; Tricolia bella 1; Triphora sp. 3; Vermicularia sp. 1

JunLind-9: Acmaea pustulata 7; Acteocina candei 2; Anachis spp. 3; Arca sp. 14; Arcopsis adamsi 2; Astraea phoebia 6; Atys caribaea 4; Bailya intricata 2; Bailya parva 9; Barbatia candida 4; Barbatia tenera 3; Brachidontes domingensis 62; Brachidontes sp. 1; Calliostoma jujubinum 3; Cardiomya perrostrata 1; Cerion sp. 2; Chama sp. 2; Cheilea equestris 3; Chione pygmaea 3; Chlamys sp. 1; Codakia orbicularis 1; Codakia orbiculata 3; Codakia sp. 22; Cyclostrema cancellatum 1; Cymatium sp. 7; Cypraea sp. 1; Daphnella lymneiformis 67; Dentalium sp. 14; Diodora minuta 33; Diodora sp. 1; Emarginula pumila 27; Engina turbinella 3; Favartia cellulosa 1; Fissurella barbadensis 1; Haminoea sp. 3; Heliacus cylindricus 2; Hemitoma emarginata 4; Hemitoma octoradiata 3; Ischadium recurvum 1; Kurtziella sp. 1; Laevicardium laevigatum 1; Lima lima 1; Lima scabra 3; Lucapina sp.3; Marginella sp. 5; Mitra barbadensis 4; Morula nodulosa 1; Morum oniscus 1; Nassarina monolifera 2; Nassarius albus 2; Natica canrena 39; Natica livida 2; Nitidella nitida 3; Papyridea soleniformis 1; Persicula fluctuata 3; Petaloconchus sp. 9; Plicatula gibbosa 1; Pseudostomatella erythrocoma 1; Pyramidella dolabrata 7; Pyrene ovuloides 8; Pyrgocythara candidissima 1; Semele sp. 3; Siliquaria squamata 2; Strigilla sp. 34; Tellina gouldii 7; Tellina listeri 4; Tellina similis 29; Tricolia bella 6; Tripterotyphis triangularis 1; Trivia sp. 4; Turbo sp. 3; Turritella exoleta 3; Vermicularia sp. 2

JunLind-10: Arca sp. 2; Barbatia candida 1; Barbatia tenera 1; Chama sp. 6; Chiton 1; Codakia orbiculata 1; Engina turbinella 1; Hyalina albolineata 1; Nassarius albus 1; Natica canrena 3; Plicatula gibbosa 2; Risomurex rosea 1; Tellina gouldii 2; Tellina similis 1; Terebra sp. 1; JunLind-11: Arca sp. 2; Astraea caelata 1; Bailya parva 1; Barbatia candida 1; Chiton 1; Codakia orbicularis 1; Conus mus 1; Cymatium sp. 2; Dentalium sp. 3; Diodora sp. 1; Hemitoma octoradiata 1; Isognomon sp. 1; Lima pellucida 1; Lima scabra 3; Lucina sp. 1; Mitra barbadensis 1; Nitidella nitida 1; Tellina fausta 1; Tellina listeri 3; Trivia sp. 1; Turbo sp. 1; Vermicularia sp. 1

January live mollusc counts for all taxa found.

June live mollusc counts for all taxa found.