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SPECIES PROFILE

American Paddlefish (Polyodon spathula)

Polyodon

IUCN STATUS

Vulnerable

American Paddlefish (Polyodon spathula) — Mississippi River basin from Montana to the Gulf of Mexico; now restricted to larger rivers and reservoirs in the central US

CONSERVATION STATUS

Vulnerable

CLASS

Actinopterygii

GEOGRAPHICAL RANGE

Mississippi River basin from Montana to the Gulf of Mexico; now restricted to larger rivers and reservoirs in the central US

DIET

Filter feeder

HABITAT

Large slow-moving rivers and reservoirs with open water for filter feeding; spawns over gravel bars in spring

🔬 Classification

PHYLUM

Chordata

CLASS

Actinopterygii

ORDER

Acipenseriformes

FAMILY

Polyodontidae

GENUS

Polyodon

📋 Description

SIZE

1.0–1.5 m body length (excluding paddle); 7–27 kg; paddle (rostrum) up to 30 cm long

COLORATION

Smooth grey skin with no scales; distinctive long spatula-shaped rostrum; large subterminal mouth; heterocercal tail like a shark

ADAPTATIONS

Rostrum is covered in electroreceptors detecting electric fields of zooplankton swarms; filter feeds by swimming with mouth open; can detect planktonic crustaceans from 9 m

🌿 Ecology

HABITAT

Large slow-moving rivers and reservoirs with open water for filter feeding; spawns over gravel bars in spring

DIET

Filter feeder

GEOGRAPHIC RANGE

Mississippi River basin from Montana to the Gulf of Mexico; now restricted to larger rivers and reservoirs in the central US

REPRODUCTION

Spring spawning migration to gravel bars; eggs broadcast over clean gravel; no parental care; late maturity (7–10 years)

DIET DETAILS

Almost exclusively zooplankton (copepods, Daphnia) filtered from the water column by fine gill rakers; occasionally small fish and insects

⚠️ Threats & Conservation

PRIMARY THREATS

Overharvest for caviar and meat; dam construction blocking spawning migrations; habitat degradation; invasive species competition

💡 Interesting Facts

1

The American Paddlefish is a living relic — an ancient fish lineage over 300 million years old whose relatives swam with dinosaurs; it is the largest freshwater fish in North America.

2

The Paddlefish's long rostrum is not used for digging but is packed with thousands of electroreceptors that can detect the faint electrical fields produced by zooplankton swarms from metres away.

🔭 Sighting Guide

📍 BEST PLACES TO SIGHT

Lake of the Ozarks near Osage Beach, MO, is a key Paddlefish habitat in the Osage River system

Keystone Lake near Mannford, OK, has documented Paddlefish populations with spring snagging season

Lower Missouri River near Kansas City, MO, has Paddlefish in deeper river channels and backwaters

🗓️ BEST TIME TO SIGHT

Spring. Spawning runs in March and April bring Paddlefish to tailwaters below dams on the Missouri and Mississippi River systems.

🎯 SIGHTING TIPS

March to April below Table Rock Dam on Lake Taneycomo in MO and Keystone Lake in OK for snagging season and guided viewing.