NJ Outdoor Women's League Meeting Eels Revealed March 2006

	"Among the first ready-made foods were eel pies," read the slide. Not exactly burgers and fries, but for centuries eel has been a part of diets around the world and continues to be to this day. Japan alone consumes about 2 billion dollars worth a year. In response to worldwide concern that this commercially desirable food is in decline, research has been under way to confirm this decline, discover its possible causes and learn more about eels in general. Dr. Mark Sullivan who received his doctorate in Marine Biology and works for the Rutgers University Institute of Marine and Coastal Sciences, came to our May meeting to share with us how some of these studies are conducted, the interesting interpretations of their results and at the same time gave us a glimpse into the complex life cycle of the American eel.	Elvers - click image to enlarge
	Simply put, the life of the American eel, Anguilla rostrata, begins and ends in the Sargasso Sea, a plankton rich area in the North Atlantic Ocean south of Bermuda. Biologists believe that the abundance of necessary nutrients in this area and its proximity to the Gulf Stream are major factors for it being the spawning grounds for the eel.

When eels become sexually mature (which can be anywhere from 8 to 30 years from their birth), they make their way out of the freshwater ponds, lakes, streams and estuaries toward the Atlantic Ocean. At this point the changes in their body color as well as other physical changes signal the silver eel stage and on their journey to the Sargasso Sea they cease to eat. At the journey's end, a female eel will lay as many as 15-20 million eggs; a male eel fertilizes these eggs. Their task completed, the spawning adults die.

The leptocephalus larva, which emerges from the egg, is less than 2 inches long, has a leaf-shaped transparent body through which only the eyes are visible and has markings reminiscent of the veins in a leaf. The larva is transported by the Gulf Stream northward taking as long as a year to reach the coastline of the United States. Its European cousin will continue on north and then veer east to the continent of Europe.

By the time the larva reaches the estuaries of North America it has changed into the glass eel stage; it is still transparent and is about 2½ inches long. After being in the freshwater environment, it takes on pigmentation. The male "elver" eels will stay in the estuaries while the females will continue upstream to find their way into rivers, lakes and streams. An elver not only has the capacity to live an extended time out of water, but can also, amazingly, crawl over land, up dams, spillways, and rapids to reach its destination. Once there, an eel, now in the yellow eel stage, will continue to grow (females will be about 5 feet long and the males half that length) and as adults will remain there (up to 30 years) until they reach sexual maturity.

Although throughout its lifetime an eel faces many threats to its survival, it is during the glass eel stage that the eel is most desirable and subject to heavy harvesting for markets in Asia (Japan in particular) for the expressed purpose of being raised there to supplement that country's own declining population of eel. According to Dr. Sullivan this over-fishing prompted the passage of a law in 1999 prohibited the taking of glass eels. The decline in the numbers of the European eel, the crash of the eel population in the St. Lawrence River and data showing a decline in North America from 1980 through 2000 has precipitated dialog about putting the American eel on the Endangered Species List. Dr. Sullivan has been involved in ongoing studies to determine trends for the population of all life stages but particularly the glass eel, and also to discover reasons for those trends.

At present he is conducting studies out of the Rutgers University Marine Field Station in Tuckerton, NJ in conjunction with similar studies being done in Beaufort, North Carolina. One way of collecting data, that is fishing, is with the use of a medium plankton net in the Great Egg Inlet near the Mullica River. The net is placed in the water during the incoming floodtide at night; tied to the guardrail of the bridge over the water and left there for a half hour. It is then removed from the water, the contents dumped into a bucket and sorted according to species of sea life. Data collected were combined with those done in Beaufort, NC.

The data from both areas between 1986 and 2004 showed no decline in eel populations but does not take into consideration studies between 1980 and 1986. It also showed that in New Jersey eel were accessing the estuaries later and later each year. Some explanations might be global warming and the intensity of Gulf Stream plus the lack of an adequate food supply. The results at Beaufort, on the other hand, showed little change but since it is closer to the Sargasso Sea the eel's journey would be shorter. It also showed that the size of the glass eels is declining in both inlets. There was also a correlation between the amount of winter rainfall and the number of eels present in both inlets, (the odor of fresh water is a signal to the eel to look for an inlet). The increase also peaked during the lunar phase prior to the full moon due to a higher tide.

Another method being used to collect data in the Mullica River-Great Egg Harbor/Great Bay Estuaries is an "eel catcher". Made of unraveled rope fibers attached to a PVC and ceramic base, it can be used in a variety of habitats and excludes most other species of fish. The eel will seek it out to hide from predators and as many as 1000 eels a night can be caught, counted and measured.

Dr. Sullivan supplemented his talk with slides and we thank him again for spending the time to give us an up to date account of what is being done to learn more about this unusual and commercially important creature.

- Sandy Norman

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