While the recent cold snap and snowfall in Louisiana was an interesting sight to see, it had an extremely detrimental effect on the state’s saltwater fish. The Louisiana Department of Wildlife & Fisheries has estimated that some 40,000 fish succumbed to the brutal cold in 77 separate fish kills.
The trouble started on Jan. 20, when record cold temperatures engulfed Louisiana. The freezing conditions lasted for several days, with record snowfall, as well as freezing rain, touching even the southernmost parts of the state.
The saltwater fish species native to Louisiana start to die off when water temperatures dip below 40 degrees, and the effects worsen the longer that temperature stays that low. All basins in the state’s coastal waters saw water temperatures below 40 degrees. Some areas, particularly very shallow ones, dipped as low as 32 degrees. This resulted in the widespread fish kills.
Since the travel advisories were lifted on Jan. 24, LDWF has investigated fish kills statewide in the lead-up to the fisheries meeting held on Feb. 6. The data from those observations indicates the mortality events were coast-wide, with the majority of deaths occurring in shallow water. This is likely because the fish in those areas were not able to reach the relative safety of warmer, deeper waters less affected by the arctic blast. Some shallow marsh ponds even saw ice form around the edges in this event.
Though the fish kills were spread all over the Louisiana coastline, not all areas were affected to the same degree. LDWF reports that the highest overall mortality of a variety of species have been observed in the coastal marshes between the Mississippi and Atchafalaya Rivers, except for Striped Mullet, which had high observed mortality east of the Mississippi River.
The highest levels of spotted sea trout and black drum mortalities have been observed in the Terrebonne Basin and Timbalier Bay. The largest concentration of red drum and sheepshead mortalities were observed in the Barataria Basin, which is sure to hurt that fishery.
Fish Kill Totals
- Striped Mullet — 19,107
- Spotted Sea Trout — 12,552
- Red Drum — 6,568
- Sheepshead — 2,657
- Black Drum — 2,142
Such a freeze is unusual, but not unprecedented. LDWF points out a freeze that occurred in late December 1989. During that event, water temperatures dipped below 32 degrees for about 100 hours near Grand Isle. That resulted in ice forming on Lake Pontchartrain and other larger coastal water bodies.
There was also a freeze in 2018, which was similar to the one that just occurred. Based on data collected from the 2018 incident, and the current one, LDWF expects the upcoming season to be similar. Anglers should expect fishing for common and popular inshore saltwater species to be below average in the coming months.
LDWF biologists will continue to investigate fish kills and document dead fish to attempt to assess the damage to the fishery, but the full effects of the freeze may not be understood for a year or longer. Regular LDWF monitoring, which tracks the relative abundances of key species, should help quantify the damage in coming years.
Currently, the LDWF has not implemented any regulatory changes as a result of this event, but would like the public to notify them of any fish kills by calling 1-(800)-442-2511.
