As a private tour guide in Portland, Angela Clark’s one-woman Working Waterfront Tours promise behind-the-scenes glimpses of Portland’s marine-dependent businesses. On a hot summer’s morning, the dead fish and live lobsters were definitely the highlights of a one-hour tour for 14 campers, ages 5 to 12, from the Portland Center for Cultural Exchange. While every child in this crowd resides here in Maine, surprisingly not a one had yet had the opportunity to tour the Fish Exchange. First Clark explained the concept of a fish auction. Then, upon entering, our tour gingerly walked over the slippery floor here — be careful! it’s slimy! — for this stop’s biggest highlight: an ice-filled container packed with 300 pounds of cod.

Then Clark whipped up a huge cod by its mouth with two fingers and patiently lectured her captivated crowd. “What do auctioneers look for when bidding on fish?” began Clark. “They look at the eyes to see if they’re clear, then they open the gills and it’s not really sticky it’s a pretty fresh fish.”

“Weird eyeballs,” noted Madeline, a seven-year-old shivering in her little pink T shirt — the Fish Exchange, of course, is a highly refrigerated warehouse.

“It’s like winter in here,” quipped several children, almost all of whom then bravely touched a dead fish or two.

Blinking, once again, in the bright sunshine outside, Clark’s tour then continued; her two favorite topics are Maine current fishing regulations and the history of Portland’s waterfront. From colonial days of molasses trading, when workers were paid in rum, she also loves to conjure images of 19th century landfill efforts, musing on what a modern-day architectural dig might turn up. Passing “Net Desert,” a lot along the waterfront where fishing nets get repaired, she tells of the time when train tracks snaked along this same waterfront, imagining the time when grain traveled by train from Portland to Canada. Zooming into the present, Clark attempts to engage this crowd’s interest in legislative efforts to keep Portland’s waterfront marine dependent, but the crowd seems more invigorated by the smell of potential lunch when Clark explains a new, thriving waterfront business, Morrison’s Clam Chowder. Then, in a moment of shade, Clark allowed her wilting crowd to cool, seizing the moment to explain the strenuous jobs and 24-hour-on-call lives of Portland’s five ship pilots.

“Anyone know the difference between a wharf and a pier?” tossed out Clark as we troop over to Maine Lobster Direct, which thanks to an agreement with our guide, welcomed us in. (A wharf, according to the Oxford English Dictionary, is parallel to the shore, while a pier is perpendicular.)

Then our Lobster 101 lesson began in earnest. The best-question award went to the little girl who pondered if lobsters had brains. When Angela hauled a four-pound lobster out of a tank, almost every child picked it up gently or “shook hands” with an appendage.

Clark wound up with an explanation of the amazing capabilities of the Maine Spill Response Corporation, but frankly at this point our group had turned fidgety. They glazed over as Clark informed them that we were now standing on Widgery Wharf, which dates back to 1777, making it Portland’s oldest wharf. Quickly summing up the mood of her crowd, Angela Clark switched gears, telling fascinating stories about the hordes of ravenous rats living under the luxury condominiums of Chandler’s Wharf, across the way. Pointing to the lobster traps piled high nearby, as Clark described these rats feasting on dried seafood remains, the tour definitely wound up on a child-appropriate note: lunchtime.

This summer marks Angela Clark’s fourth year of offering her customized Working Waterfront Tours, accommodating everyone from school children to cruise-ship passengers. For further information, contact Angela Clark at 207-415-0765; her email address is workingwaterfront@hotmail.com. Tours cost $10 for adults, $7 for children; group rates are available.