Cocahoe Minnows – Freshwater Aquaculture

Chris Green, Assistant Professor of Aquaculture, Louisiana State University AgCenter

Cocahoe minnows (photo courtesy of Chris Green, Louisiana State University AgCenter).

Cocahoe ninnows (Fundulus grandis) are top minnows native to the intertidal marshes of the Gulf of Mexico waters. They are known by other names including: mud minnows, bull minnows, and Gulf kilifish. As a common estuarine species, it is often consumed by game fish, thus making it a popular live baitfish for marine anglers. Throughout their range, they are used to target flounder, speckled trout, red drum, and other game species. Gulf killifish spawn throughout a protracted spawning season with biweekly peaks in spawning activity that coincide with the peak spring tides from March through October. During the peak tidal events, eggs are deposited in flooded marsh grass, where they are left stranded when the tide recedes. The tough, desiccation-resistant eggs are able to be air incubated, whereby they incubate at an accelerated rate due to the high level of atmospheric oxygen. During the following peak tide, the eggs are inundated and simultaneously hatch due to the decrease in the level of oxygen in the water. This ensures that the majority of eggs across multiple clutches hatch at the same time. This evolutionary adaptation to spawning provides an opportunity for potential producers to coordinate the hatch of multiple cohorts into large groups for growout. After the water temperatures fall below ideal spawning conditions (26-28°C) during the winter months, adults transition to the deeper, more saline waters of the intertidal channels where they are more difficult to collect by bait harvesters. Because the majority of marine baitfish are wild-caught, the ability to culture Gulf killifish represents a potential revenue stream for growers and marinas that supply wild bait to anglers, especially at times when wild harvest is limited by environmental conditions. Additionally, cultured Gulf killifish could be size-graded to ensure a steady, healthy supply of live baitfish at various size classes for particular target species.