Rainbow Smelt Declining in Great Bay

Jeff Barnum

Are we losing yet another piece of our Great Bay ecosystem? After two winter seasons of declines in rainbow smelt, most recreational fishermen would likely say “yes.” The smelt run seems to be going the way of the Great Bay oyster – downward.

Every winter, ice fishermen haul their shacks onto the rivers feeding Great Bay to await the return of rainbow smelt, catching this local delicacy through the ice on hooks baited with sea worms. Their only concern is whether or not there will be enough ice. This year there has been plenty of ice, but for the second year in a row, there are few smelt.

Fishermen wonder where the rainbow smelt have gone. Early reports for this season have been so dismal that most fishermen have not even bothered to pull their shacks on to the ice. Only a few very optimistic anglers set up on the Squamscott River in Stratham. The local bait shop isn’t even carrying sea worms this year – not wanting to get stuck with the inventory. No one, not even the New Hampshire Fish and Game Department, has a definitive answer as to why the number of smelt returning is so low.

Smelt shacks on the Squamscott River

Smelt shacks on the Squamscott River

Adult rainbow smelt typically overwinter in estuaries and bays and then spawn in early spring in pool and riffle areas above or in the head-of-tide areas of coastal streams and rivers. Juvenile smelt remain in the estuary, bay, or sheltered coastal areas through the summer, and sometimes through late fall. They stay closer to shore generally unless they need to go in search of cold waters during warm months. Their relatively small size – six to eight inches – precludes them from being netted at sea.

The geographic range of rainbow smelt has been constricting for the last few decades, no longer extending south to the Chesapeake. Is the problem ocean temperature? Are smelt abandoning Great Bay for northern waters? Maybe, but even in Maine, smelt numbers have reportedly declined by 50%. Climate change may be a factor. Temperature, dissolved oxygen, pH, turbidity, total nitrogen and phosphorus, and periphyton are also all suspected of playing a role in spawning success.

While we may not have too much immediate influence over the big picture at sea, we do have control locally—especially with water quality in the spawning grounds of Great Bay. The future of the iconic smelt run in the Great Bay estuary is yet another reason to reduce pollution and restore the health of our waters.

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