Long Island Sound Oyster Health

Six scientists wearing waders stand at a folding table with a tidal stream to the right of them and a beach and Long Island Sound behind them. They are measuring and sorting oysters. Two orange buckets are visible. The weather is cloudy. — Scientists count and measure oysters at Fence Creek in Madison, Connecticut. Photo Credit: NOAA Fisheries/Kristen Jabanoski

Overview

Project Goals

Collect baseline data on Eastern oyster population health in Connecticut and New York
Develop science-based guidance for effective oyster restoration in Long Island Sound

Project Description

Oysters provide benefits beyond sustainable seafood. Natural, restored, and farmed oysters can improve water quality and provide habitat for fish. Oyster restoration efforts are increasing in Long Island Sound to maximize these benefits, also called ecosystem services. Connecticut Sea Grant recently released a state guide to shellfish restoration, and restoration projects are already underway in New York. We are collecting baseline data that will help promote the sustainable growth of oyster populations.

Restoration and Disease Dynamics

Expanding natural oyster populations can benefit people and the environment. However, scientists do not know how unmanaged oyster populations affect the spread of oyster disease in Long Island Sound. Oyster diseases can intensify as oysters age. Early harvest, as is done in aquaculture, can be an effective strategy to manage disease. Natural and restored oysters often live longer, and scientists do not know how this affects the prevalence of disease in these populations.

Research Sites

Map of Connecticut and Long Island, New York, with orange dots indicating Ash Creek and Fence Creek in Connecticut and Cold Spring Harbor and Huntington Harbor on Long Island. — Map of four research sites used in the Long Island Sound oyster health project. Credit: NOAA Fisheries/Gillian Phillips

Working with local partners, we are taking a comprehensive look at oyster population health in natural and restored oyster populations. We will assess the health of oysters at four sites monthly over multiple years. Two sites are in Connecticut, one at Ash Creek in Fairfield, and the other at Fence Creek in Madison.

The other two sites are on the north shore of Long Island at Cold Spring Harbor and Huntington Harbor.

Oyster Population Health

Two scientiest on oyster bed at low tide,collectint oysters in white basket.

We are collecting baseline data on the age, size, and reproductive status of oysters. We want to find out whether oyster populations are declining, stable, or growing. We are measuring the prevalence and intensity of three pathogens that previously caused oyster die-offs in the region: Dermo, MSX, and SSO. At each research site, we are also continuously recording environmental water quality data.

Together, these data will improve our understanding of how the population structure, disease burden, and environment interact to affect the overall health and success of the oyster population.

Understanding population dynamics and the current disease prevalence in natural and restored oyster populations will help us predict oysters' disease resilience. It will help scientists and communities restore oyster beds in a way that supports population growth while minimizing the spread of disease. Our data will also help restoration projects plan for climate change to make sure projects are sustainable over the long term.

Study Methods

Monthly Sampling

We sample each of our four research sites monthly from March to November. During monthly sampling, we measure oyster shell size and body condition. We also take tissue samples from up to 30 adult oysters for disease diagnostics and reproductive staging. We use histology to track gonad maturation and time of spawning. This helps us understand the reproductive fitness of an oyster population.

Two hands wearing purple nitrile lab gloves removing tissue samples from a shucked oyster using metal forceps and dissection scissors and placing the samples on a piece of paper towel. The samples are separated into pools of tissue using a metal scalpel. — Shellfish Health and Disease Technician Mariah Kachmar takes samples from an oyster for disease diagnostics.

Disease Surveillance

We use a novel molecular method called triplex quantitative polymerase chain reaction to measure the prevalence and severity of Dermo, MSX, and SSO. This method can be more efficient than traditional methods. We are validating our molecular methods with traditional methods to improve our comparisons with historical oyster disease data for Long Island Sound.

Biannual Population Surveys

We do a population survey at each site biannually. During the survey, we collect data on:

Oyster bed area, height, and rugosity
Oyster population density
Survival of all oyster sizes
Size distribution of oysters

We also collect data annually on the presence and survival of young oysters and the juvenile oyster growth.

Environmental Data

We are collecting water quality data during each sampling trip and placing instruments at our sites to collect data continuously. The data we’re collecting includes:

Water temperature
Salinity
Dissolved oxygen
Chlorophyll-a, a measure of algal growth in the water
pH, a measure of how acidic or basic the water is

Our research will determine whether water quality and physical reef characteristics relate to the population health and/or disease prevalence. It will also improve our understanding of the seasonal dynamics of oyster health, disease, and reproduction.

Understanding the Health Of Long Island Sound's Oyster Beds

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