What is the Mobile-Tensaw Delta?

The Mobile-Tensaw Delta is the second-largest river delta in the contiguous United States, after the Mississippi: a vast wetland wilderness at the head of Mobile Bay in coastal Alabama, covering roughly 260,000 acres (cited in a 200,000 to 300,000-acre range) of bottomland hardwood forest, cypress-tupelo swamp, and freshwater and brackish marsh, about 45 miles long and up to 16 miles wide. It is fed by the Alabama and Tombigbee rivers, which join to form the Mobile River and then braid out into the Tensaw, Apalachee, Blakeley, and Spanish rivers before reaching the bay. Its biodiversity, including more than 120 fish species and hundreds of birds, earned it the nickname America's Amazon, and its 190,000-acre core was designated a National Natural Landmark in 1974.

How big is Mobile Bay?

Mobile Bay covers about 413 square miles, making it one of the largest estuaries in the United States. It is often called the fourth-largest, but that ranking is by freshwater inflow (about 62,000 cubic feet per second, drawing on the Mobile River basin, which is the fourth-largest US river basin by flow and sixth by drainage area), not by surface area, where the bay ranks somewhat lower. The bay is also strikingly shallow, averaging only about ten feet deep outside its dredged ship channel. That combination of huge freshwater and nutrient delivery into a broad, shallow, warm, brackish basin makes Mobile Bay extraordinarily productive and gives it one of the highest fish-species diversities of any US estuary.

What is a Mobile Bay jubilee?

A jubilee is a natural event in which bottom-dwelling fish and crustaceans, especially flounder, blue crabs, shrimp, and eels, crowd into the shallows along the shore, where they can be gathered easily by hand or net. It is caused by hypoxia: on a calm summer night the shallow bay stratifies and the bottom water loses its oxygen, and when a gentle east wind and rising tide push that oxygen-poor water toward the eastern shore, the bottom animals are squeezed against the beach into the last band of breathable, oxygenated water. Mobile Bay is, by the scientific record, the only body of water on earth where jubilees occur regularly and predictably. A jubilee is a natural, recoverable phenomenon, distinct from a pollution-driven fish kill.

Where and when do jubilees happen?

Jubilees happen on the eastern shore of Mobile Bay, the Fairhope, Daphne, and Point Clear stretch, in the summer, roughly June through September. They almost always occur in the pre-dawn and early-morning hours, on a rising tide, after a hot, calm, still stretch of weather with a light wind out of the east. They cannot be scheduled, but experienced eastern-shore residents learn to anticipate them by reading those conditions, which is why the local communities have a long tradition of watching the bay on still summer mornings and spreading the word when one begins. Fairhope in particular is strongly identified with the jubilee, though the tradition is shared across the whole Eastern Shore.

What fish can you catch in Mobile Bay?

The Mobile Bay and delta inshore fishery centers on redfish (red drum) and speckled trout (spotted seatrout), the bread-and-butter targets, along with prized southern flounder, plus sheepshead, tripletail, and cobia. The estuary also serves as a major nursery for these species. Out at the bay's mouth, Dauphin Island is a hub for both bay and Gulf fishing, and offshore, Alabama runs the largest artificial-reef program in the country, supporting one of the South's best red snapper fisheries. Tarpon move through the nearshore Gulf in summer. Up in the fresh delta, you can also catch largemouth bass, bream, and catfish, which is part of why the Mobile-Tensaw is described as offering six sporting verticals on one tank of gas.

What is the best inshore fishing season on Mobile Bay?

Redfish and speckled trout are catchable year-round, with redfish schooling and feeding hard in the cooler months. Flounder run on a tighter schedule, staging and migrating out to the Gulf to spawn in the fall, the classic October-to-December flounder run; note that Alabama closes the flounder season for the month of November to protect that spawning push, so confirm current dates. Sheepshead concentrate around structure in the cold months. Offshore, red snapper has a tightly regulated summer season, and tarpon run nearshore from roughly June into September, peaking around the July full moon. Always confirm current seasons, size and creel limits, and closures with the ADCNR Marine Resources Division.

Where do you base a Mobile Bay or delta trip?

The bay has two shores and a head, each with its own base. The Eastern Shore, Fairhope, Daphne, Point Clear, and Magnolia Springs in Baldwin County, is the jubilee coast and the genteel side, anchored by Fairhope's downtown and the historic Grand Hotel at Point Clear (a landmark since 1847); it is the base for eastern-shore fishing, the jubilee, and Weeks Bay. Spanish Fort, at the head of the bay across the Battleship Parkway Causeway, is the gateway to the delta and the Delta and Bay Conservation Center at 5 Rivers. Dauphin Island, at the bay's mouth, is the saltwater and offshore base, and Bon Secour and the Fort Morgan peninsula, with Bon Secour National Wildlife Refuge, anchor the southeast.

Why is the Mobile-Tensaw Delta called America's Amazon?

The nickname America's Amazon, popularized by biologist E.O. Wilson, reflects the delta's extraordinary biodiversity. The Mobile-Tensaw Delta and the broader Mobile River basin form one of the most aquatically biodiverse temperate river systems in the world, with more than 120 species of fish, hundreds of bird species, and exceptional diversity of turtles, snails, salamanders, and other aquatic life, including many species found nowhere else. The combination of a huge, intact bottomland-and-swamp wilderness and the convergence of several major rivers concentrates an Amazon-like richness of life into one coastal Alabama delta, which is why conservationists use the comparison and why the delta's 190,000-acre core was named a National Natural Landmark.

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Mobile Bay and the Mobile-Tensaw Delta Field Report: Inshore Redfish, the Second-Largest Delta, and the Jubilee Phenomenon

Aug 18

12 min read

Updated: Oct 21