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| Joe Charlebois | Guest Columnist | Harry M. Covert | Norman M. Covert | Hayden Duke | Jason Miller | Ken Kellar | Patricia A. Kelly | Edward Lulie III | Tom McLaughlin | Patricia Price | Cindy A. Rose | Richard B. Weldon Jr. | Brooke Winn |

DOCUMENTS


The Tentacle


February 22, 2007

Atlantic Warming Thrice

Tom McLaughlin

The first part of this series showed conclusively Atlantic warming is occurring off the coast of Ocean City. The second section demonstrated that brown pelicans, a species normal in the south, have migrated north over the past 10 years and is directly affected by temperature variations. This section explores other biological indicators including fish and birds.

The Department of Natural Resources (DNR) in West Ocean City performs fish studies each year at 20 sites over the summer. Trawling, pulling a net behind a boat and seining, throwing a net and pulling it to shore in shallow waters are the methods used. Everything captured alive in the nets is counted and recorded.

On occasion a species appears in the Coastal Bays from the south that cannot be considered an indication of Atlantic warming. For example, a pompano, found only in the tropics, may be captured in the nets Storms and bizarre currents could force these fish into the inlet and they take up residence.

Non-commercial Back Bay species are unaffected by commercial and recreational fishermen. Rules and regulations imposed by governments obviously affect the numbers of fish caught. Catch reports are incomplete and inaccurate. Several commercial fishermen have reported most temperature-dependent species have arrived and departed on time over the past 10 year, except for the 2006-year.

Graphing the results of non-commercial fish catches by DNR demonstrates mixed results. Three species - white mullet, weak fish and silver perch - show a slight increase in the trend. The graph for menhaden remains flat from 1993 to 2001, while increases are noted from 2002-2006.

Three other fishes - Atlantic silver side minnows, hogchokers and pigfish - show no increase in numbers. Obviously, no conclusions about Atlantic warming for the Coastal Bays can be surmised with these species.

Cownose rays are the bane of oystermen. They have mouth plates capable of crushing oysters and clams, eating the insides. In a much-publicized account, the Army Corps of Engineers dumped one million oysters into Virginia's Wicomico River. Within a week, they became an all you can eat buffet for the rays, wiping out the $45 million project.

Not only do they attack oysters, they also entangle themselves in fishing nets, creating problems for the watermen. They are perceived to be a nuisance and some feel need to be eradicated.

However, they only produce one offspring per year and once they reach a danger level, they are unlikely to rebound. One idea taking hold is to find an economic use for them. They have been harvested and having cooks and chefs serve them in restaurants has been tried. "If we can find an economic use for them, then conservation will follow, the thinking goes." Wallets and purses (one Internet site sells them for $59) made from ray skins is also a possibility. As any Coastal Bay or Atlantic fisherman knows, the rays are ubiquitous.

One researcher who studies these creatures has noticed that some of the rays are beginning to arrive in the mouth of the Chesapeake Bay earlier and earlier. They are not the main school, but small groups. It would be presumptuous to state that some rays are arriving at the Back Bays earlier than normal because nobody seems to be studying them. However, this could be another biological gauge of Atlantic warming.

Black skimmer, royal, sandwich and gull billed terns are all possibilities for Atlantic Warming. However, it is difficult to determine when they arrive, where they nest and the number of offspring. There seems to be no central database where birders record observations for the Coastal Bays.

MSX, Dermo and SSO

Organisms MSX, dermo and SSO are responsible for the death of millions upon millions of oysters and the demise of a billion dollar industry in both the Chesapeake and Back Bays. Despite millions in research monies, nobody is quite sure of the ecology of MSX, how it's transmitted from oyster to oyster, or its life cycle. SSO (seaside organism) is located in saltier areas like our Coastal Bays and is similar to MSX. Dermo, a fungus, remains a mystery. All three work in the same way. They weaken the muscle of the oyster, cause the shells to open, making it easier for them to be eaten by other creatures.

Are these organisms temperature dependent? Some think so. After the inlet was cut in 1933, most of the oysters were wiped out because of salinity differences and hard clams replaced them.

But, some of the oysters returned and the famous Chincoteague oysters made a partial come back. However in recent times, in conjunction with the increase in temperature, dermo, MSX and SSO made a return, wiping out populations that were farmed or native to the area.

Do MSX, dermo and SSO remain dormant until bay temperatures reach a certain point, or do oysters become more susceptible at the higher temperatures? Probably a combination of both.

In the early 1900's, a thriving oyster industry in the Back Bays abruptly succumbed. The Chincoteague Oyster was lost, except for small pockets following Darwin's Theory of "survival of the fittest." People working in oyster shacks, where they were processed, found jobs on the mainland.

One effort to restore the population comprised of digging a trench from the ocean to the bays across Ocean City. The thinking was to "freshen" the bay water with ocean water. Hundreds of men were employed, tents erected for food and sleeping quarters.

Unfortunately, the results were not reported and it is not known if the inlet was completed. Had it been, the increased salinity would have destroyed the rest of the surviving population. There were no temperature buoys around and the cause of this malady remains a mystery. Could this be a biological cycle, or attributed to increased water temperature?

In the 1980'and 1990's where temperature data is more prevalent, there have been waves of oyster die offs in the farmed and the remaining populations. While Atlantic warming is certainly part of the problem, leaking septic tanks, discharge from poultry processing plants, run off from farms, applying fertilizers, and development make the Back Bays unsuitable for oyster farming.

The future holds the development of an oyster that is disease resistant, temperature tolerant and grown in large cages or flats. These filter feeders may make an economic comeback. However more scientific research will be required.

The major biological reactions to Atlantic warming in Northern Worcester County are tourists, pelicans, cownose rays and the three oyster parasites. Back Bay non-commercial fishes seem to show no reaction; the same as other bird species.

Of the three, the major increases in oyster parasites are the most troubling for the near future. Like viruses and flu that sweep the world, one cannot predict the effects of warming on other, yet unknown, parasites, lurking in the waters that may be triggered by warming and wreck havoc on the environment.

Acknowledgements:

I would like to thank the many individuals at the Maryland Department of Natural Resources, the Virginia Institute of Marine Science, the National Buoy Data Center in Mississippi, local commercial and recreational fishermen, and people at the Assateague Island National Seashore. Special thanks to my brother Jeff McLaughlin and friend Mike Lewis who checked and rechecked the data for me. I am also indebted to life long friend Dr. Harry Womack, of Salisbury University. The errors and omissions are my own and I take full responsibility for them.



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