Friday, May 16, 2014

Atlantic Sturgeon Migration Research

For a third year the NJDEP Division of Fish and Wildlife has deployed 19 acoustic receivers in Delaware Bay to track migration patterns of Atlantic sturgeon.

With the endangered species listing of Atlantic sturgeon, effective April 6, 2012, research on this species has gained significance. The Division's portion of the project is to purchase, assemble, deploy and maintain 19 receivers in the Delaware Bay. Data is downloaded monthly from each receiver to detect movement of Atlantic sturgeon tagged with acoustic telemetry tags.

The shortnose sturgeon, Acipenser brevirostrum, and its cousin, the Atlantic sturgeon, Acipenser oxyrhynchus, are ancient fish species that originated more than 70 million years ago. Of the seven species of sturgeon in North America, two are found in New Jersey.

Common names in the mid-Atlantic region:
Shortnose sturgeon - shortnosed, little sturgeon, roundnoser and mammose
Atlantic sturgeon - sea sturgeon, common sturgeon, sharp-nosed and big sturgeon

Sturgeon have a skeleton made of cartilage, not bone. These fish have flattened, elongated bodies covered with five rows of bony plates called scutes. Sturgeon tails are heterocercal, meaning the upper lobe of the tail is much longer than the lower lobe.

Shortnose sturgeon have short, blunt snouts. Their upper body is olive-yellow to gray-blue; the underside is milky white to dark yellow.

Atlantic sturgeon snouts are tapered in the young but broad as adults and noticeably upturned. Their upper body is gray to blue-black with white spines on the scutes.

Both sturgeon species have two pairs of barbels (feelers) projecting from their lower jaw and used to detect food. Sturgeon are toothless and extend their tube-like mouths to ingest prey, which then is ground in the stomach.

Shortnose sturgeon is the smallest sturgeon along the East Coast. They grow to about 56 inches and can weigh up to 15 pounds, but average closer to 10 pounds.

In contrast, Atlantic sturgeon reach an average mature length of 10 feet, but can grow to 15 feet and 800 pounds.

New Jersey's recreational state record Atlantic sturgeon, caught off Sandy Hook in 1994, weighed 82 pounds.

Those fishing inshore waters may encounter white buoys marking the receivers which are set at depths generally less than 20 feet. Buoys are labeled "NJDEP Research" and should be avoided.

 As part of a multi-state collaborative effort, the Division has partnered with several states to develop a multi-year effort directed at providing state, federal, and regional management authorities with information necessary to successfully conserve and ultimately restore the population of sturgeon in the mid-Atlantic region.

The receivers complement the existing receiver array within Delaware Bay, specifically on the NJ side, to ensure complete coverage of the sampling area. The additional coverage allows for greater detection of Atlantic sturgeon and provides the ability to monitor immigration and emigration from the Delaware Bay.

In 2013, the receivers recorded 31,401 detections from 233 different fish. Over 61 percent of the fish detected were Atlantic sturgeon, while 22 percent were sand tiger sharks. Other species detected included an American shad, a sandbar shark, a spiny dogfish, and a black drum tagged in March, 2011, at the Kennedy Space Center in Florida. The majority of Atlantic sturgeon were detected in May and had been tagged by Delaware State University.

Reports of sturgeon sightings and interactions are also important to this research; please see for information on submitting a report.

Large Atlantic sturgeon captured in the Atlantic Ocean for research.

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