The Booming Texas Snook Population: Coming Soon To A Bay Near You?​

Joel Anderson | Perry R. Bass Marine Fisheries Research Station
The Booming Texas Snook Population: Coming Soon To A Bay Near You?​

Figure 1. The abundance of snook in TPWD gill nets through time.The orange bars represent the annual catch of all three Texas species of snook combined.

If you’ve ever caught a snook in Texas, you’re among a select group of anglers. Fishes in the snook family (of which there are 12 recognized species) usually have a tropical distribution, occurring most commonly in South and Central America. However, three species of snook occur in Texas, including the common snook, the fat snook, and a third more rare species called the Mexican snook. In Texas, these species are encountered frequently in the Lower Laguna Madre, but are relatively rare elsewhere.

There are multiple unique features of snook biology that distinguish these species from other sport fish in Texas. First, they are equally tolerant of both fresh and saltwater, and are found commonly in rivers year round. Second, snook species in general (including those in Texas) display a form of hermaphroditism in which males transition into females as they grow older. If you catch a very large snook, it is likely a female. Third, hybridization, which is otherwise rare in Texas’ marine fishes, is widespread in the snook family. In fact, a collaborative genetic study conducted by researchers at Texas Parks and Wildlife (TPWD) and Texas A&M Corpus Christi has shown that most fat snook caught in Texas are actually hybrids with Mexican snook. Finally, despite being a tropical family of fishes, there is evidence that snook populations in Texas are actually expanding. It is this last point that requires more examination, as the expansion of snook in Texas’ waters may present increased opportunities for Texas’ anglers.

The TPWD long-term gill net data indicate a 3 to 5-fold increase in the number of adult snook present in Texas’ bays since the 1980s. Although abundance is episodic (meaning there are peaks and valleys in abundance through time), the long-term trend is upwards. Warmer summers and mild winters have likely resulted in resident snook, whereas in the past Texas may have harbored only a migrant population.

In addition to gill nets, TPWD uses shoreline seine nets to measure the abundance of small organisms (think smaller than 4 inches) in the bay. Recent seine samples also paint a fairly rosy picture regarding the snook trend.In the years 1980 – 2004, 14 juvenile snook were observed in seine samples coast-wide.Since 2005, that number has skyrocketed, with 60 juveniles observed, including 12 in a single Laguna Madre sample in the fall of 2017. Although these numbers may not seem overwhelming, the increasing presence of juvenile snook in Texas is significant because it suggests that adults are sticking around to spawn, rather than going elsewhere. This implies the potential for a future population boom, as juveniles that are spawned in Texas may themselves stick around and contribute to the local population when they mature.

As it turns out, the population boom may be upon us. The fall 2017 TPWD sampling season produced a record number of adult snook, which were observed further north than ever before.Record gill net catches occurred in almost every bay system in Texas, including the first ever encounter of a common snook in Texas’ northernmost bay, Sabine Lake. To give you an idea of just how extreme the numbers were in 2017, more snook were caught coast-wide last year in gill net samples (100, total) than were caught in the entire decade of the 1980s (93 total). Furthermore, the 25 juveniles encountered in 2017 bag seines more than tripled the previous single-year record of 7, which occurred in 2014.

Given the rapidly increasing abundance of snook in Texas, the pending question is whether we can expect this to continue into the future. One notable trend in that regard is that other tropical marine species, such as gray snapper, tarpon, and green sea turtles, have also increased significantly in abundance in Texas within the past 20-30 years, suggesting a tropical invasion, perhaps driven by a warming trend. In concert with an overall general increase in Gulf of Mexico water temperatures, average shoreline water temperatures in Texas bays have risen approximately 1-2 degrees (F) since 1980. This is very likely the driver of the range expansion of tropical species, and if water temperatures continue to increase, so will the likelihood that these populations will continue to expand. One caveat to all of this is extreme cold winter temperatures, such as those experienced coast-wide in early January 2018. Extreme cold can negatively impact tropical species that are not well adapted to cold winter conditions, causing mortality or otherwise driving them southward where temperatures are more tolerable. Coast-wide fish kills associated with the January freeze may result in a temporary decrease in abundance of snook and other tropical species for the next few years.

So what’s the outlook going forward? Snook populations in Texas are larger than ever before, they’re growing, and the range of these species in Texas may slowly be expanding northward. Cold winter temperatures might occasionally stem the tide, as snook are famously intolerant of cold water. But each time this has happened over the last 30 years, the species seems to have recovered in record fashion. If the recent population boom is any indication, soon the Laguna Madre may not be the only place that anglers can target snook in Texas.

Next month intern Danielle de Vacque will answer some questions heard at boat ramps.