HUMAN IMPACT on QUEEN CONCH POPULATION DENSITY by Shelbey Rogers

HUMAN IMPACT ON QUEEN CONCH POPULATION DENSITY by Shelbey Rogers

A Thesis Submitted to the Faculty of The Wilkes Honors College in Partial Fulfillment of the Requirements for the Degree of Bachelor of Arts in Liberal Arts and Sciences with a Concentration in Marine Biology

Wilkes Honors College of Florida Atlantic University Jupiter, FL May 2019

HUMAN IMPACT ON QUEEN CONCH POPULATION DENSITY

by Shelbey Rogers

This thesis was prepared under the direction of the candidate’s thesis advisor, Dr. Jon Moore, and has been approved by the members of her/his supervisory committee. It was submitted to the faculty of The Honors College and was accepted in partial fulfillment of the requirements for the degree of Bachelor of Science in Liberal Arts and Sciences.

SUPERVISORY COMMITTEE:

______Dr. Jon Moore

______Dr. William O’Brien

______Dean Ellen Goldey, Wilkes Honors College

ACKNOWLEDGEMENTS

A special thank you goes to Dr. Moore for being an incredible thesis advisor as well as Dr. O’Brien for being my second reader. A special thank you also goes to Dr.

Wetterer for providing insight and guidance for my thesis during our Field Biology class.

I would also like to thank the staff and faculty at the Harriet L. Wilkes Honors College for providing four years of fantastic experiences that would not have been available on any other campus.

I would like to thank my great-grandmother Margie for sharing with me her love of the ocean and culturing an appreciation for zoological sciences.

I would also like to thank Morgan Schad, Arielle Routledge, Stephanie Brinez, and

Edwin Velasquez for providing a helping hand and assisting me in the field during the research portion of my thesis.

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ABSTRACT

Author: Shelbey Rogers

Title: Human Impact on Queen Conch Population Density

Institution: Wilkes Honors College of Florida Atlantic University

Thesis Advisor: Dr. Jon Moore

Degree: Bachelor of Arts in Liberal Arts and Sciences

Concentration: Marine Biology

Year: 2019

Queen Conch, Lobatus gigas, is considered a threatened species that is native to the Caribbean and Gulf region, including South Florida. This thesis examines Queen

Conch population density as affected by human activity in several areas along Florida’s

East coast. Areas that are heavily trafficked by humans have shown a sharp decline in

Queen Conch presence. Spot surveys were completed by the author in Tequesta, Boca, and Deerfield Beach. Community surveys published by Florida Fish and Wildlife were completed in The Florida Keys. Results showed a decrease in Queen Conch population numbers in areas heavily trafficked by humans.

TABLE OF CONTENTS

Section Page Number

Introduction………………………………………………………………………..1-4

Materials and Methods…………………………………………………………….4-9

Results……………………………………………………………………………..10-12

Discussion…………………………………………………………………………12-15

Bibliography……………………………………………………………………….16-18

LIST OF TABLES AND ILLUSTRATIONS

Figure A-1 shows an overhead view of the Tequesta site. The yellow line shows the length of the site and the red line shows the width. Image was created with the help of Google Maps……………………….……………..….5 Figure A-2 & A-3 shows one of several Queen Conch aggregations that were found at the Tequesta Site on March 2 nd, 2018. Figure A-3 shows Queen Conch moving further apart as the high tide comes in. Pictures were taken by Shelbey Rogers…………………………………………………………………..6 Figure A-4 displays the paths walked along the Boca Raton site for the spot surveys. A1 and A2 are both two different starting points, while B1 and B2 are two different end points. Image was created with the help of Google Maps……………………………………………………………………………..7 Figure A-5 displays the paths walked along the Deerfield Beach site for the spot surveys. A1 and A2 are both two different starting points, while B1 and B2 are two different end points. Image was created with the help of Google Maps……..……………………………………………………………………….8 Figure A-6 depicts every site that Queen Conch were counted at across the Florida Keys in 2017 and was created by Florida Fish and Wildlife (FWCC 2017)…………………………………………………..………………………….9 Figure A-7 displays the number of Queen Conch counted at the Tequesta site as well as the size class they fell into………………………………………...10 Figure A-8. Each orange spot indicates the estimated population of adult Queen Conch found at each site that was indicated in Figure A-6. Figure from FWCC (2017)..…………………………………………………………………..11 Figure A-9. Each orange spot indicates the estimated population of juvenile Queen Conch found at each site that was indicated in Figure A-6. Figure from FWCC (2017).…………………………………….………………………..11 Figure A-10 Each orange spot indicates the total estimated population of Queen Conch found at each site that was indicated in Figure A-6. Figure from FWCC (2017)………………………………………………………………..……12 Figure A-11. Each orange spot indicates the total estimated population of Queen Conch found at each site that was indicated in Figure A-6. Figure from FWC (2017)…….…………………………………………………………..12

INTRODUCTION

In 1992, the Queen Conch (scientific name Lobatus gigas) was officially listed under Appendix II of CITES international trade agreement, meaning it was recognized as a threatened species that would soon become endangered if there was not a quick reduction in overfishing (NOAA, 2014). Commercial fisheries for Queen Conch in the state of Florida had already been closed since 1975; and in 1986, a research program dedicated to monitoring the recovery of the species was started (Glazer, 2001).

The Queen Conch is a large marine mollusk that lives inside a pink or orange shell that is made of calcium carbonate (Kreipl et al., 2011) and has a life span of up to thirty years (NOAA, 2014). Their age of reproductive maturity is reached at three, or four years depending on the resources available to them during their maturation process

(Stoner et al., 2012). Juvenile Queen Conch living in a nutrient rich environment will have to spend less energy on securing resources and will be able to use that energy instead to develop their shells.

Seagrass beds and sand flats are the habitats most associated with Queen Conch.

Here, they feed on seagrass detritus and serve as an important part of the overall trophic structure in seagrass beds (Stoner, 1989). They serve as important prey to other mollusks and marine reptiles (Jory and Iversen, 1983) and their empty shells are often repurposed by hermit crabs (Berg, 1975).

Queen Conchs are native to the tropical waters of the Caribbean, the Gulf of

Mexico, and South Florida (NOAA, 2014). It is here that they have been one of the most important human food staples since the pre-Columbus era of the Caribbean (Stoner et al.,

2018). This means it has been engrained into many of the native cultures of this region, and its importance has been passed down throughout generations—making the value of the Queen Conch cultural and economic.

Their importance to the Bahamas, for instance, has contributed to the need for government-sanctioned Marine Protected Areas, but there is growing evidence that these areas are not helping the overall population as previously planned (Tan, 2018).

Unfortunately, the Bahamas are not the only place witnessing the significant decrease of its Queen Conch populations. Countries throughout the Caribbean have suffered similar losses (Peel and Aranda, 2003).

Conch meat used to be harvested in South Florida at twenty-thousand to fifty- thousand pounds per year in the mid-1960s (Kumazawa, 1980). The harvests decreased significantly by the early 1970s, suggesting that the populations of Queen Conch that were previously an abundant staple in Florida were diminishing (Kumazawa, 1980).

For something that is so important to the culture, economy, and environment of several countries, there should be greater motivation to protect and ensure the survival of the Queen Conch.

In 2001, a study was conducted by the Florida Marine Research Institute in conjunction with a NOAA partner and the Caribbean Marine Research Center (Glazer,

2001). The purpose of the study was to compare the recovery of Queen Conch in the

United States with populations of Queen Conch in the Bahamas where the species is still heavily fished. What they found was the Bahamas still had higher population counts and the reason they concluded for this was the availability of larval Queen Conch.

A study that yielded similar results was done in the Marine Protected Area in

Exuma Cay in the Bahamas. Despite the no-fishing policy established in these areas, there was a 71% recorded decline in adult Queen Conch populations (Kough et al., 2017).

The decline in population supports the hypothesis that local Queen Conch populations are supported by larval recruitments from the metapopulation of Queen Conch in the

Bahamas. As long as overfishing of the general population continues, local populations will continue to suffer with it.

This research lead to a new experiment: raising Queen Conch in hatcheries and releasing them as juveniles with a better chance of survival (Glazer, 2001). This initiative was inspired by successful aquaculture work that was already done in the Turks and

Caicos (Davis et al., 1987).

There are several more issues contributing to Queen Conch decline other than overfishing. Despite their official status as threatened, there has been a serious lack of enforcement of CITES fishing laws that lead to illegal fishing and trade (Theile, 2001).

Poaching is not a strange concept to conservation work (Actman, 2019), but there still seems to be a lack of initiative or will when it comes to stemming the impact.

There is also the issue of biases in the industry that can further harm Queen

Conch population stability under the guise of management. For example, the minimum shell length for legal fishing in Belize is 17.8cm (Strasdine, 1988). This is a reproductive maturity minimum. However, most scholars in the area would agree that shell length is an inappropriate measure for adult conch (Wood and Olsen, 1983). The best way to determine maturity in Queen Conch is by checking for a flared lip and the thickness of said lip (Bahamas Reef Environment Educational Foundation, 2014).

The real issue with using the minimum as acceptable for conch harvest is that

Queen Conch are density-dependent spawners. A certain population size must be met for successful reproduction to carry on future populations (Stoner et al., 2012).

The purpose of this study is to show that despite various efforts, there is more contributing to Queen Conch population decrease than just fishing. Human activity, specifically near heavily frequented beaches disturbs areas that could be potentially inhabited by recovering Queen Conch populations.

MATERIALS AND METHODS

Three sites in Florida were surveyed by students of Harriet L. Wilkes Honors

College; data from the Florida Keys, published by the Florida Fish and Wildlife

Conservation Commission (FWC), are also analyzed in this study. In each surveyed site,

Queen Conch were counted and checked for sexual maturity by measuring a shell length of over 17.8 cm, as previously mentioned in the introduction. To ensure visibility, googles were kept on hand in case of the tide coming in and a flashlight was also brought along. The camera of the Samsung Galaxy S8 smartphone was used to take photographs of the Tequesta, Deerfield, and Boca Raton sites. Measuring tape was used to measure the shell length of the Queen Conch found, and a legal pad and pen were used to record the data for individual Queen Conch as well as the size of each. The size was used to determine the sexual maturity of each Queen Conch found.

Google Maps was later used to provide figures of the locations researched.

Tequesta

Figure A-1 shows an overhead view of the Tequesta site. The yellow line shows the length of the site and the red line shows the width. Image was created with the help of Google Maps. Coordinates to the site entrance: 26°57'46.54"N; 80° 4'45.79"W

Width of study area: 18.05 meters

Length of study area: 362.52 meters

A spot survey was done in the site in Tequesta, Florida on March 2nd, 2018. Two practice surveys were done before this so that the volunteers could get used to what they were looking at and for. This area is the least trafficked by humans out of all the sites examined by the author. This survey was done during low tide at 4:20 PM because low tide is the easiest time to spot Queen Conch. During low tide they tend to congregate in larger groups more out in the open, as displayed in Fig. A-2. As the tide starts to come in, they disperse and move closer to the large prop roots of the red mangroves that line the coast or the sea beds that are further out in the water (Fig. A-3). They become fewer and are further apart, thus making them more difficult to find.

A-2

A-3 Figure A-2 & A-3 shows one of several Queen Conch aggregations that were found at the Tequesta Site on March 2nd, 2018. Figure A-3 shows Queen Conch moving further apart as the high tide comes in. Pictures were taken by Shelbey Rogers. Every shell was measured in length before being examined to determine if there was a live snail inside. Dead shells were either empty or inhabited by hermit crabs. The data were later sorted into a table that accounted for live adults vs dead adults and live juveniles vs dead juveniles.

Boca Raton

Figure A-4 displays the paths walked along the Boca Raton site for the spot surveys. A1 and A2 are both two different starting points, while B1 and B2 are two different end points. Image was created with the help of Google Maps. Coordinates of A1: 26°21'44.58"N; 80° 4'5.29"W

Coordinates of A2: 26°21'44.56"N; 80° 4'4.28"W

Coordinates of B1: 26°21'55.74"N; 80° 4'4.81"W

Coordinates of B2: 26°21'55.60"N; 80° 4'3.74"W

Site Width: 26.45 meters

Site Length: 340.8 meters

A spot survey was done at Red Reef Park at Boca Raton on June 14th, 2018 at 10

AM with two people walking along the coast at two different distances searching for

Queen Conch. The first person was walking along the tidal line, the second person was walking about 25 meters out. The tide was high at 2.4 feet. Because of the area that the

survey was completed, the tide did not make a difference in the potential for conch spotting. The traffic in this area is higher than Tequesta, but lower than Fort Lauderdale.

This is because it is considered a protected park and there is a fee to access it. There was no living Queen Conch spotted in the area here, but there was shell debris.

Deerfield Beach

Figure A-5 displays the paths walked along the Deerfield Beach site for the spot surveys. A1 and A2 are both two different starting points, while B1 and B2 are two different end points. Image was created with the help of Google Maps. Coordinates of A1: 26°18'59.53"N; 80° 4'28.81"W

Coordinates of A2: 26°18'59.53"N; 80° 4'26.43"W

Coordinates of B1: 26°19'11.11"N; 80° 4'27.69"W

Coordinates of B2: 26°19'10.54"N; 80° 4'25.59"W

Site Width: 67 meters

Site Length: 352 meters

A spot survey was done at Fort Lauderdale Beach, a heavily trafficked area. A

spot survey was conducted with two people surveying along the coast at two different

distances searching for Queen Conch on May 29th at 8:20am during a low tide of 0.4 feet.

The surveyor moving from A1 to B1 was walking, the surveyor moving from A2 to B2

was snorkeling. There was no living Queen Conch or shell debris spotted here.

Florida Keys

Figure A-6 depicts every site that Queen Conch were counted at across the Florida Keys in 2017 and was created by Florida Fish and Wildlife (FWCC 2017). The FWC conducted community-based surveys to estimate how many Queen Conch were found in different sites across the Florida Keys. Each site is displayed by a blue dot in Figure A-6 above. Adults were determined by the development of their flared lips. The information from each survey was gathered and compiled in 2017 (FWCC 2017).

RESULTS

Tequesta

Figure A-7 displays the number of Queen Conch counted at the Tequesta site as well as the size class they fell into. In total, ninety-three Queen Conch were counted. Of those ninety-three, thirty- four were live adults, fifty were live juveniles, and nine were dead juveniles. No dead adults were found. Adult shells were measured with a range from 17.9 centimeters to

24.2 centimeters. Total juveniles were measured with a shell length of 3 centimeters to

17.6 centimeters.

Boca Raton

While no live Queen Conch specimens were found in the Reed Reef Park, Boca

Raton survey, several pieces of Queen Conch shell debris were found by the person doing the shore survey.

Deerfield Beach

No live specimen or shell debris was found.

The Florida Keys

Figure A-8. Each orange spot indicates the estimated population of adult Queen Conch found at each site that was indicated in Figure A-6. Figure from FWCC (2017).

Figure A-9. Each orange spot indicates the estimated population of juvenile Queen Conch found at each site that was indicated in Figure A-6. Figure from FWCC (2017).

Figure A-10 Each orange spot indicates the total estimated population of Queen Conch found at each site that was indicated in Figure A-6. Figure from FWCC (2017).

Figure A-11. Each orange spot indicates the total estimated population of Queen Conch found at each site that was indicated in Figure A-6. Figure from FWC (2017). The results of the surveys done in The Florida Keys show a strong correlation between human activity and Queen Conch population density. Each of the largest spots on the charts are in areas where there is low human impact, or the site is further away from the coast. The smallest dots correlate to highly frequented areas, or places that are closer to human activity.

DISCUSSION

During both training surveys with the volunteers and the final spot survey at the

Tequesta site, not a single other human was documented as being within the site parameters. The Tequesta site had a hidden entrance that is not easy to find. There is a popular strip of beach just south of the mapped site, but there was an obvious increase in

Queen Conch shell size as we went further north, away from the human activity. The lack of human activity in the surveyed area could be contributing to the higher numbers of

Queen Conch that were seen here in comparison with any other site.

However, another contributing factor could be the seagrass beds and the mangroves that filled the area. These features provide hunting grounds and space to hide from predators for the Queen Conch. These environmental factors were also something not seen at any of the other sites that were measured.

The Boca Raton site has a different way of stemming human activity in comparison with other sites. Because it is considered a protected area, it charges visitors for access to the park. Thus, in comparison to a free access beach, it has a smaller amount of human activity. There was still at least one human for every meter measured along the site parameters. There were no live Queen Conch spotted as this site, but there was a lot of shell debris. This hints at a possible offshore population living in deeper waters.

Whether it is the human activity that contributes to the lack of Queen Conch spotting in this site, or the lack of seagrass beds and mangroves has not been determined. If seagrass beds or coral reef was found offshore that would be an indicator that the difference is more habitat-related than human-related.

The map picture chosen for the Deerfield Beach site was zoomed out a bit more than others specifically to capture the amount of human activity nearby. Boardwalks lined with active restaurants and shops are bound to draw in even more human activity and create a high amount of light and noise pollution, as well as, high amounts of beach littering. The beach here is also open access and had more than one human for every meter that was counted for the site parameters. There was no live specimen found here and no shell debris to indicate an offshore population either. This could either be due to the high amount of human activity, or the lack of habitat.

Figure A-11 was included for the Florida Keys data to show the sites from a more zoomed-in view. From this view it is evident that the larger populations are further offshore than nearshore, which is especially true in Key West where the closest large population is quite a few miles out. Most of the sites closer to the shore held no Queen

Conch at all. This is consistent with the Glazer (2001) report.

It is also important to note that population size decreases the closer we get to

Miami, a major city with a high human population. There was no evidence of the

Biscayne Bay population that was previously recorded by Glazer (2001) in the data reported in 2017 (FWCC 2017). However, there were also no sites directly inside of the bay. Seventeen sites were surveyed just outside of the bay and out of all seventeen, only two Queen Conch were spotted (FWCC 2017).

Each of these sites display a pattern of increasing Queen Conch numbers in places where the human population is diminshed and in decreasing Queen Conch sightings in places where humans are more active. Whether or not this is heavily contributed to by human activity or environmental factors cannot be conclusively determined from this

data. Further research into sites with similar environments and varying human activity would be a useful continuation of this study. It would also be useful to look for a potential offshore population at the Boca Raton site and sites inside Biscayne Bay.

Having more surveys done in different parts of each site would also be useful for developing more conclusive results.

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