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The Scoop on Shellfish

Written on: May 17th, 2024 in Education and Outreach, Natural Resources, Wetland Animals

By Ashley Tabibian, DNREC’s Shellfish and Recreational Waters Program

What do you think of when you think of oysters, clams, and mussels? For being so small, they are somewhat complex creatures with almost superhero like abilities. Do you think of how nutritious they are? According to WebMD, shellfish are low in calories, high in protein and contain omega-3 fatty acids and other nutrients. Do you think about their ability to clean up the water? Shellfish are filter feeders that help remove excessive nutrients and other compounds from the water. Do you think about their structure? Shellfish beds can stabilize shorelines and reefs, and can sequester carbon while providing habitat for other animals. Do you think about the jobs that are centered around shellfish? The National Oceanic and Atmospheric Administration (NOAA) published in 2018 that oysters and clams accounted for $315 million of marine aquaculture, and in 2022 estimated a global market of $108.4 billion

Shellfish are a major food source across the world but can present a unique risk of foodborne illness if not harvested and handled properly. Their relatively large surface area allows them to warm up quickly after harvest, allowing bacteria to reproduce at a faster rate if shellfish are not kept cool. As filter feeders, they concentrate pathogens at a higher rate than surrounding waters which is why it is important to be sure they come from Approved, or safe to harvest, waters. When eaten raw or partially cooked, any pathogens inside shellfish are not killed during the cooking process making it important to not only keep them under the proper temperature and get them from Approved water, but also to keep them from contacting other foods and surfaces that could cause cross-contamination.

So, who keeps track of all this health stuff? That is where we come in – the DNREC Shellfish Program. We are part of the Department of Natural Resources and Environmental Control (DNREC) within the Division of Watershed Stewardship, and our main mission is to protect public health by minimizing the risk of foodborne illness due to the consumption of shellfish. The University of Cambridge defines shellfish as an animal that lives in water and has a shell, but our program deals exclusively with bivalve shellfish that pose a certain and specific risk to human health due to how they are consumed. Although scallops, crabs and conchs are, by definition, shellfish, they are not usually consumed raw and whole. For example, scallops are usually shucked and cooked, so you are just eating the adductor muscle and the foodborne pathogens are killed by heat during the cooking process. However, if you consume the scallop whole and raw, the same special foodborne illness risks apply. Meanwhile, an oyster is often shucked and kept on ice to be eaten raw and whole.

The DNREC Shellfish Program works in three ways to ensure product meant for human consumption are delicious and nutritious for healthy persons when harvested and handled properly.

First, it is necessary to make sure the animals come from Approved waters. Since shellfish are filter feeders, you eat what they eat, so it is important they come from a clean area. DNREC tests the water and maintains an interactive, online map on our website showing where the harvest of shellfish is Approved, Seasonally Approved, or Prohibited. You can also find this map published in the Delaware Fishing Guide. You can use this map to determine Approved areas to recreationally harvest clams and mussels. Please note the Division of Fish and Wildlife manages acreage in the Inland Bays for leases for shellfish aquaculture.

Second, our program staff conduct routine inspections of all shellfish shippers and processors to ensure compliance with national food safety requirements and those specific to the shellfish industry. Delaware is a member of the Interstate Shellfish Sanitation Conference (ISSC) and must follow all requirements set forth by the organization. The ISSC made up of state, federal and industry representatives working in cooperation with the U.S. Food and Drug Administration to ensure compliance of state programs with national standards.

The third part of the program is enforcement which is handled by DNREC Fish and Wildlife Natural Resources Police who regulate catch limits and harvesting methods for both commercial and recreational harvesters.

Harvesting in Delaware

There are numerous species of bivalves in Delaware, however, the four primary species are the Eastern Oyster, Hard Clams, Razor Clams and Ribbed Mussels. The Eastern Oyster is harvested commercially but is illegal to harvest recreationally to protect the populations. Hard Clams are harvested both commercially and recreationally. The Razor Clams are harvested only recreationally. Ribbed mussels are typically not harvested commercially or recreationally. Want to harvest some? Reference that interactive, online map to see where the Approved areas are.

Below are some simple tips, tricks, and things to keep in mind to make sure you can enjoy raw shellfish from Delaware waters and markets.

1. If you are at risk or immunocompromised, eat only fully cooked shellfish. The at-risk community can include those with liver disease, diabetes, alcohol use disorder, kidney disease/failure, stomach disorders, cancer or any other condition or treatment that weakens the immune system. If you are unsure, consult your doctor.
2. Keep it cold! Keep shellfish below 45℉. Immediately refrigerate/ice shellfish. If they exceed this temperature, harmful bacteria can reproduce into an infectious dose.
3. Keep it clean! Wash your hands, surfaces and equipment before and after handling shellfish. If you have an open wound, avoid contact with the water and seafood. If you get a wound while working with shellfish, clean it thoroughly and use a waterproof bandage.
4. Keep it separate! Do not allow the shellfish to contact other foods such as in coolers containing water that has fish or crabs in it or other non-ready to eat items. Do not allow shellfish to contact water from a non-Approved harvest area.

Looking for more information about the Delaware Shellfish Program? Visit our webpage and browse through our educational material, regulations, maps, and more.

Tags: Animals, DNREC, Tidal Wetlands