Science Wednesday: A Case of Crabs and People

About the author: Steve Jordan’s environmental career is rooted in a childhood spent in the woods and creeks of suburban Maryland and along the shores of Chesapeake Bay. After graduate school and a couple of decades working in Chesapeake Bay science and management, he joined EPA’s Office of Research and Development as a scientist and manager at the Gulf Ecology Division.

Before the 1970s, intense development of our coastal areas was limited mostly to scattered resort cities separated by large areas of sparsely populated or undeveloped land. As population grew and roads improved, coastal development exploded—and sprawled.

Beach front high-rises are the most obvious result of all that coastal development, but the whole complex of barrier islands, back bays, bayous, and tidal rivers along our Atlantic and Gulf coasts is now arrayed with homes, businesses, roads, golf courses, docks, bulkheads, and everything else that comes with development. Gulf of Mexico coastal watersheds lost over 370,000 acres of wetlands from 1998 to 2004, mostly to development (see: U.S. Fish and Wildlife Service).

Except for the occasional hurricane, the coastal zone is wonderful habitat for humans. It is also essential habitat for many kinds of animals and plants, including the fish and shellfish that shore residents cherish.

Do the habitat needs of humans conflict with the habitat needs of other coastal residents? Our research at EPA’s Gulf Ecology Division indicates that they can. With my coauthors, Lisa Smith and Janet Nestlerode, I developed a mathematical model to simulate how loss of seagrasses and salt marshes could affect the important blue crab fishery in the U.S. Gulf of Mexico.

The model used information from many existing small-scale studies of how tiny, young (juvenile) crabs depend on aquatic vegetation until they are large enough to avoid predators. We linked data from these studies to electronic maps of the essential habitats and long-term, Gulf-wide commercial fishery data.

Putting it all together, we were able to predict that minor, local losses of essential habitats, multiplied many times in many places, could have serious negative effects on the future of the crab fishery. The main scientific advance in this work has been to make a connection between small-scale ecological studies and large-scale population modeling as it is used in fishery science.

With colleagues from the Pacific Coast and elsewhere, we are extending this type of research to other species and coastal areas. We hope this research will contribute to better understanding of the cumulative effects of coastal development on ecosystems and valuable ecological resources.

graph
Figure caption: Simulated U. S. Gulf of Mexico hard blue crab landings 2004-2050. The two lower curves show different scenarios of habitat loss: SAV = submersed aquatic vegetation (seagrasses); hardened shore = loss of salt marsh edge to shoreline structures.

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Maryland Without Crabs?

About the author: Lina Younes has been working for EPA since 2002 and chairs EPA’s Multilingual Communications Task Force. Prior to joining EPA, she was the Washington bureau chief for two Puerto Rican newspapers and she has worked for several government agencies.

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In my nightly Web surfing, I came across an article on the “Top 25 Things Vanishing From America.” As expected, the loss of some “old technologies” like the VCR, dial-up internet access, phone landlines, analog TV, made the list. However, what struck me enough to write about it in today’s blog was the mention of the Chesapeake Bay Blue Crabs and honey bees.
Maryland has been my home for nearly 28 years. The blue crab, is practically a state icon. I must note that my family and I enjoy eating crabs in many ways. In this era of going “local” in our culinary habits, you would think that living in the Free State, eating crabs is the right thing to do. Yet this Internet article has made me reflect and question—should we keep crabs off the menu for a while?

Overfishing, water pollution and excessive nutrients are threatening the blue crab and aquatic wildlife that live in and around the Chesapeake Bay, the largest estuary in the United States. This important watershed spans six states—Maryland, Virginia, Delaware, Pennsylvania, West Virginia, New York and the nation’s capital, Washington, DC. EPA and its state partners work closely together to accelerate progress towards a healthy Bay. Through the Chesapeake Bay Program, EPA is trying to make a difference in restoring the blue crab habitat by working to improve water quality and submerged aquatic vegetation. In the meantime, the role of setting harvest regulations for the blue crab lies primarily on the states along the Bay.

Whether you’re concerned about the Chesapeake Bay or your local watershed, there are simple steps you can take in your home, school, community or the workplace to protect these precious aquatic resources. For example, conserve water! Don’t pour used motor oil down the drain! Used oil from a single oil change can ruin a million gallons of fresh water—A year’s supply for 50 people. Use greenscaping techniques in your garden. Bottom line—learn and get involved.

¿Maryland sin cangrejos?

Sobre la autor: Lina M. F. Younes ha trabajado en la EPA desde el 2002 y está a cargo del Grupo de Trabajo sobre Comunicaciones Multilingües. Como periodista, dirigió la oficina en Washington de dos periódicos puertorriqueños y ha laborado en varias agencias gubernamentales.

En mis viajes por Internet, encontré un artículo sobre las “Principales 25 cosas que están desapareciendo de América”. Como era de esperarse, la pérdida de algunas “viejas tecnologías” como los VCR, las líneas telefónicas terrestres, la TV análoga figuraban en la lista. Sin embargo, lo que me chocó y motivó a escribir el blog de hoy fue la mención de los cangrejos azules de la Bahía de Chesapeake y las abejas de miel.

Maryland ha sido mi hogar durante casi 28 años. El cangrejo azul es casi un ícono estatal. Debo destacar que a mi familia a mí nos encanta comer cangrejos de diversas formas. En esta era de abogar por los hábitos culinarios locales, uno pensaría que viviendo en Maryland, el comer cangrejos sería aconsejable. Sin embargo, con este artículo del Internet, me he puesto a pensar–¿acaso debemos eliminar los cangrejos del menú por algún tiempo?

La pesca en exceso, la contaminación del agua, y los nutrientes excesivos están amenazando el cangrejo azul y la vida silvestre acuática en y alrededor de la Bahía Chesapeake, el estuario más grande en Estados Unidos. Esta importante cuenca fluvial abarca seis estados—Maryland, Virginia, Delaware, Pensilvania, Virginia Occidental, Nueva York y la capital federal, Washington, DC. EPA y sus socios estatales trabajan estrechamente para acelerar el progreso hacia una bahía saludable. Mediante el Programa de la Bahía de Chesapeake, EPA está tratando de hacer una diferencia en la restauración del hábitat del cangrejo azul al trabajar para mejorar la calidad del agua y la vegetación acuática sumergida. Entretanto, el rol de establecer las regulaciones para la cosecha del cangrejo azul recae primordialmente sobre los estados vecinos a la bahía.

Independientemente de su interés en la Bahía del Chesapeake o su cuenca fluvial local, hay pasos sencillos que puede tomar en su hogar, colegio, comunidad o lugar de trabajo para proteger estos preciados recursos acuáticos. Por ejemplo, ¡conserve agua—cada gota cuenta! ¡No eche el aceite de motor usado por la alcantarilla! El aceite usado de un simple cambio de aceite puede contaminar un millón de galones de agua fresca—el suministro de 50 personas para un año. Utilice técnicas de jardinería verde en su jardín. A fin de cuentas—aprenda y participe activamente en la protección ambiental.

Editor's Note: The views expressed here are intended to explain EPA policy. They do not change anyone's rights or obligations. You may share this post. However, please do not change the title or the content, or remove EPA’s identity as the author. If you do make substantive changes, please do not attribute the edited title or content to EPA or the author.

EPA's official web site is www.epa.gov. Some links on this page may redirect users from the EPA website to specific content on a non-EPA, third-party site. In doing so, EPA is directing you only to the specific content referenced at the time of publication, not to any other content that may appear on the same webpage or elsewhere on the third-party site, or be added at a later date.

EPA is providing this link for informational purposes only. EPA cannot attest to the accuracy of non-EPA information provided by any third-party sites or any other linked site. EPA does not endorse any non-government websites, companies, internet applications or any policies or information expressed therein.