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Capstone on the Bay

When I first sat down to figure out what my capstone project would be to fill in the last requirement for my degree in Marine Conservation and Policy at Stony Brook University (SBU), I felt overwhelmed with options. I was grateful to be offered a position as a Park Naturalist with Narragansett Bay National Estuarine Research Reserve (or NBNERR, for short) where I would be able to complete my capstone while working. The idea for which conservation project I would tackle came to me when I figured out the day I was relocating to the remote Prudence Island, that sits nestled in the geographic center of Narragansett Bay, June 1^st – right in time for spawning Atlantic horseshoe crab (Limulus polyphemus) season.

Prudence Island is only accessible by ferry which runs on a limited schedule, making it difficult for researchers to stay long enough in order to actually monitor the spawning horseshoe crabs that come to shore during the evening high tides occurring during the full and new moon. I was lucky enough to live on Prudence Island during my time of work, and therefore had all the time I needed to monitor the spawning horseshoe crabs in order to get an idea of the populations that may utilize this island’s shorelines for laying eggs. I was also grateful to have a wonderful co-intern, Elizabeth, to help with data collection.

The misnamed “horseshoe crabs” are actually not crabs, rather they are more closely related to spiders and scorpions than their aquatic crustacean counterparts. Being closely related to organisms often associated with danger and poison doesn’t help the horseshoe crab’s reputation out when it pairs with their fierce looks – pointy tail, hard shell, lots of legs with pinchers. However, horseshoe crabs cannot hurt you, and in fact, they help save our lives. Their blood has an important enzyme in it that is used in vaccination development for humans. The biomedical industry will, in a similar way to how humans donate blood, hook up the horseshoe crabs and take their blood to extract this enzyme. If you thought that was the only beneficial use of horseshoe crabs for humans, you’d be mistaken! They are also harvested for their use as bait within fisheries, primarily focused on eel and whelk fisheries (or conch, depending on your geographic name preference).

The popularity of horseshoe crabs within human cultures leaves them vulnerable to being exploited, removing too many before they have the chance to reach sexual maturity and reproduce. Luckily, there are many organizations across the Atlantic coast that monitor the spawning populations in order to inform law and policy makers on whether or not the populations need to be protected and set catch limits.

An additional aspect I included in my monitoring was the presence or not of the horseshoe crab’s obligate flatworm parasite, B. candida. Parasites are often thought of in a negative sense due to their undesirable effects upon their host and are widely ignored in ecological monitoring.

 I believe if an organization is attempting to conserve a certain species, it is also important to consider its associated parasites. Since parasites range vastly in shape and size, parasites can also prove difficult to monitor. However, B. candida can be easily seen on the underside of horseshoe crabs, moving around on the shell and on the legs. Although the scientific community does not believe that B. candida causes harm to the horseshoe crabs, they do lay their eggs within the horseshoe crab’s gills.  In large quantity, the eggs could potentially impair respiration. Unfortunately, there are just not enough studies done on the interactions between horseshoe crabs and B. candida. 

Therefore, I set out to determine the spawning horseshoe crabs and answer some questions. First, I wanted to see if there was a decreasing population gradient as I monitored beaches geographically northward into Narragansett Bay, because if the horseshoe crabs are migrating into the bay from the Atlantic Ocean, there should be more individuals on the southern end of Prudence compared to the northern end. Secondly, I wanted to determine if male and females will be equally distributed across all sites, because if they are here to mate there should be (at least) both males and females equally present. Lastly, I wanted to determine if the prevalence of B. candida infection in all adults, regardless of sex or location is 100%, which supports previous monitoring efforts out of SBU where 100% prevalence in adults compared to 0% prevalence in juveniles.

My findings were limited- there weren’t that many horseshoe crabs! After a short panic about “oh no, what am I going to change my capstone to this last minute” I remembered that any data, even if it’s a lack thereof, still shows something. With the minimal numbers I found, I was able to get a better picture of how horseshoe crabs within Narragansett Bay utilized the variety of beaches on Prudence Island as well as the associated parasitic reactions with B. candida. First, it was not suggested that there is a decreasing northward gradient of individuals. By comparing data collected from beaches at various points across the north /south gradient, the numbers remained higher per night on the northern site compared to middle and southern island locations.

These findings are challenging because there is no other data here to compare to. When comparing other (undisclosed) locations within Narragansett Bay, the variations of horseshoe crabs present varies by a few hundred. Perhaps the horseshoe crabs do not utilize this central island as much as anticipated, or other outside factors (e.g. previously exploited, sediment preference, bathymetry) have an effect. An explanation for the lower prevalence of B. candida infestation numbers to other datasets is that the horseshoe crabs studied on Prudence are widely dispersed and not mating, making it more difficult to spread parasites via direct contact. My hopes are that this research can be continued in future years in order to gain a better understanding of the horseshoe crabs population range and the role that B. candida may play within the horseshoe crab’s life.

Marsh Guides

 The National Estuarine Research Reserve (NERR) system was created for the collective goal of protecting and studying estuarine systems in the U.S. Unfortunately, estuaries are being threatened by the dangerously-rapid rate of sea level rise (SLR). Salt marsh habitats are especially at risk due to increasing water levels. Because they naturally build peat layers by trapping sediment from the tides and accumulating decomposing plant matter, marshes are generally able to keep pace with historic rates of SLR. However, current SLR is far outpacing the normal vertical marsh growth. Thus, coastal salt marshes are at risk of “drowning.” The drowning of these saline grasslands is alarming for numerous reasons. Without healthy marshes, the many ecosystem services marshes normally provide, including nurseries for economically important fisheries, improved water quality, and reduced flooding and erosion, are lost. The loss of healthy marshes also means the loss of an important carbon sink. Marshes act as carbon sinks by trapping carbon dioxide in the sediment and plants. As marshes drown, two issues arise: previously trapped carbon dioxide is released back into the atmosphere and atmospheric carbon dioxide is no longer removed and stored. If more carbon dioxide sits in the atmosphere, climate change will continue to worsen. Worse climate change will then lead to greater SLR, which will result in the loss of more marshes. It’s a distressing and self-perpetuating cycle.

    In order to gain greater insight into the effects of SLR on salt marshes, and in turn work toward our shared mission of protecting and studying estuarine systems, a group of New England reserves and other research institutions have developed two “How to” guides. These guides are designed to advance the research and monitoring of salt marsh vegetation, which is integral to understanding the impacts of rapidly rising oceans. As water levels rise, plant composition shifts, and marshes migrate further inland. Low marsh plants begin to take over areas previously inhabited by high marsh plants. However, high marshes often can’t move due to man-made barriers and, as a result, begin to shrink. By creating unified methods of studying vegetation, the two guides serve as a tool to track these and other SLR-related changes in salt marshes. Dr. Kenneth Raposa, NBNERR’s Research Coordinator, took part in this joint effort along with researchers at the University of New Hampshire and the Great Bay, Waquoit Bay, and Wells National Estuarine Research Reserves.

The first guide, titled “A Guide to Integrate Plant Cover Data from Two Different Methods: Point Intercept and Ocular Cover,” addresses the lack of consensus on how to estimate plant cover in tidal marshes. There are currently two common methods of cover estimation: point intercept (PI) and ocular cover (OC). The PI method calculates cover by noting the type of vegetation present at 50 fixed points within a 1-m² plot. The OC method uses visual estimates of vegetation abundance within a 1-m² plot that add up to 100% (e.g., “I see 90% salt marsh hay and 10% sea lavender in this plot”). Both methods are widely used for vegetation monitoring, which can confound interpretation when making comparisons across methods.  This guide uses a statistical relationship between the two methods to transform PI data to be more compatible with OC data, thus allowing data from either method to be compared and analyzed effectively. 

   The second guide, titled “‘How to’ Guide for Synthesizing NERRs Marsh Monitoring Data” demonstrates how to synthesize salt marsh plant community data from the national reserve system. Since understanding the effects of climate change is a top priority, the guide spotlights the NERR Sentinel Sites Program (SSP). This program monitors long-term changes in plant distribution with water level changes associated with SLR. Reserves across the nation participate in the SSP, so methodologies can vary at each site (think PI vs. OC estimates). This guide addresses these discrepancies and breaks down the steps to catalogue, standardize, and summarize data from one or multiple sites. 

   Although they focus specifically on plant community data from NERRs, these guides may also be beneficial in designing protocols and analyses for other monitoring projects. It is the ultimate hope of the authors that they provide instructive, user-friendly tools to help further study and mitigate the effects of climate change on tidal salt marshes. 

2020 Sustainable Fishing Contest

This year’s Annual Sustainable Fishing Contest will be a little different due to COVID restrictions, but we’ve got a great virtual event planned in its place! Check out the information below for all the details:

You’ll have an entire week to fish! The fishing contest will officially start on Sunday, August 9^th at 11am and end on Sunday, August 16^th at 1pm (the traditional day of the contest).

Fish anywhere from the shoreline or T-wharf dock on Prudence Island (submissions from boat fishing are not allowed); to submit an entry (no limit on how many) into the contest, you must submit a photo showing the fish and its length, to ensure all state regulations are being followed. Each photo entry must also have a time/date stamp on it and have been caught during the official contest timeframe. Also include the name of the fisherman/fisherwoman, the location, and the species. All photo entries must be received by 2pm on Sunday, August 16^th and should be emailed to Maureen Dewire at Maureen.dewire@dem.ri.gov.

As usual, we will award the Prudence Island Scupmaster prize to the person who catches the most Scup of legal size (9” & max of 30/person/day). In addition, we will be awarding trophies in the following categories: Biggest Fish; Greatest Diversity of Fish Species; Most Unusual/Unique; Most Fish Caught in a Single Day; Best Overall Photo; Best T-shirt Design.

We will not be providing t-shirts this year, but we are encouraging anyone to design their own t-shirt and show it off in your photos. Think tie-dye, puffy paint, sparkles…anything goes! One of the six sought-after trophies will be awarded to the best t-shirt design, so be sure to submit a photo of your t-shirt to Maureen.dewire@dem.ri.gov with the artists’ name for consideration.

The NBNERR staff will hold a Facebook live event on Sunday, August 16^th at 3pm to announce the winners. Winners will also be notified via email and schedule a time to pick up their trophy. 

Please remember to follow all State of RI rules and regulations regarding catch and size limits and to have a current fishing license.

Fish on!

Salt Marsh Wildlife

A Great Blue Heron strides through high tide. A coyote on the hunt trots in the dark of the night. A Green Heron stands poised amidst the wetland vegetation. These are but a few of the scenes observed this past year during a field experiment. Dr. Kenneth Raposa, the reserve’s Research Coordinator, and I, Alaina Bisson, the reserve’s 2019 Seasonal Research Assistant, developed a project examining how wildlife use salt marshes undergoing thin-layer sediment placement (TLP). TLP is a strategy involving the placement of sediment or dredged material on top of a marsh to simulate the accumulation of sediment and organic material that naturally occurs in salt marshes. TLP rapidly increases the elevation of salt marshes allowing them to withstand accelerated rates of sea-level rise.

Two salt marshes in Charlestown, RI underwent TLP: Quonochontaug (Quonnie) marsh and Ninigret marsh. Quonnie marsh had dredge material applied from December 2018 to January 2019 and Ninigret marsh had dredge material applied from December 2016 to January 2017. Quonnie marsh is considered an “early stage TLP” site when compared to Ninigret marsh, a “late stage TLP” site. At both marshes, areas where no sediment was applied are considered “control marsh.” We questioned whether wildlife would use these distinctive TLP and control marsh areas differently. In an attempt to answer this question, we set up a total of 9 motion-sensor wildlife cameras across all sites: early stage TLP in Quonnie marsh, late stage TLP Ninigret marsh, and control marsh in both. We set up the cameras in July 2019 and collected photos and videos until November 2019. Once the cameras were collected from the field, the fun began! Hundreds of hours and thousands of photos and videos later, a total of 40 species were observed across all sites. Among the most abundant species were Tree Swallow, Eastern Cottontail, European Starling, White-tailed Deer, Great Egret, and Coyote. More wading and shore birds were observed in control marsh areas, while mammals dominated both early and late stage TLP areas.

We expected the cameras to have captured a number of informative photos and videos during their deployment, but in fact, the quality of said photos far surpassed our expectations! The images captured gave us an up close look at many species, particularly those that often evade human observation, like the American Bittern, or are nocturnal, such as the Yellow-crowned Night Heron and opossum. So take a look for yourself, and virtually immerse yourself in the salt marshes of Charlestown, RI! Check out some of the many interesting snapshots and video clips captured of wildlife in action.

New Chlorophyll Lab

Bob Stankelis, former NBNERR Manager, was always seeking opportunities to increase our capability to understand estuarine processes and ecological linkages by promoting sound research and monitoring. A great example relates to the long-term System-Wide Monitoring Program (SWMP), which requires all 29 Reserves around the country to collect water samples on a monthly basis to analyze for concentrations of chlorophyll and several nutrient species. At NBNERR, these samples have always been contracted out for analysis since the program’s implementation in 2002. 

Bob’s vision for NBNERR was to have the ability to perform chlorophyll analyses in-house, those required as part of SWMP analyses as well as those part of other research and monitoring projects. Due to budget constraints, Bob’s vision was on hold until early 2019 when funds were allocated to equip a new chlorophyll analysis lab at NBNERR’s headquarters. 

To move his vision forward, Bob teamed with Dr. Kenny Raposa and Dr. Daisy Durant (Research Coordinator and Marine Research Specialist II at NBNERR, respectively) to plan and design the NBNERR chlorophyll lab. Dr. Durant, who oversees the SWMP at NBNERR, researched and purchased all of the needed equipment and materials and is already analyzing chlorophyll samples in parallel with our contracted lab for comparison. After a few months of comparison, Dr. Durant will be running chlorophyll analyses exclusively at NBNERR. Unfortunately, due to a serious and sudden illness, Bob passed away in January 2020 before the project was completed. However, it was Bob’s forward thinking and drive that inspired and guided the project and ultimately made it happen.