Observed Weights of Florida’s Common Snook From Known Length and Weight Data

Prior to 2000, it was a rare event that any angler reported catching, or even seeing, a common snook much larger than 36 inches total length, especially on the gulf coast. As the benefits of restrictive harvest regulations on this species begin to accrue, however, many lunker snook are currently reported in the catch from south Florida. Because scales are expensive, and it is human nature to want to know the weight of even nonlegal fish, anglers from all across Florida commonly request that we provide the weight of a snook larger than the legal maximum total length of 34 inches. The formula that uses length times girth squared divided by 800 to calculate an estimated weight of a generalized fish does not fit the highly variable length-weight relationship for common snook, so we provide a table of mean observed weights of snook of known lengths.

The numbers in the table represent the known weights and lengths of snook measured by fishery biologists during the past 15 years. The data consist of over 5,000 observations per coast that were taken during the snook life history study, the Fishery-Independent Monitoring seine project, the catch-and-release study, and from various red tide and cold kill events. The coast-wise difference is the most important variable because common snook from the Atlantic coast are significantly heavier at a given length than are snook from the gulf coast. Additionally, because it is currently impossible to distinguish a female from a male snook, we have combined the weights of both sexes and merely output the weight of a sexually generic snook.

Understanding the Table
In the table below, the first variable to consider is the coast from which the snook was caught. The reported weights are the means of all observed weights of common snook, plus or minus one half inch of the size category. Hence, the weight reported for a 33-inch snook is the mean of all weights for snook between 32½ and 33½ inches.There is no reason to interpolate! The observed weights are reported in pounds and tenths of pounds-not inches. Thus, 10.4 pounds is ten pounds and four tenths of an additional pound. To calculate the ounce equivalent of the number on the right side of the decimal point, multiply that number by 16. Using the previous example, 0.4 multiplied by 16 is about 6 ounces, so the snook in the example weighs 10 pounds, 6 ounces. The choice of season refines the estimated weight because snook have different weights during the winter and during the spawning season. Remember, the spawning season on the Atlantic coast occurs during May through October, while on the gulf coast it is during April through September.

If the determined weight of the snook in question falls outside the limits, i.e., the minimum and maximum observed, this is understandable and highly likely because of the high variability associated with length, weigh, and age of common snook. Snook from certain areas of southern Florida may not fit the table values at all because there were no snook from these areas in the data set, particularly the Broward-Dade-Monroe region and counties north of and including, Volusia County. If the length of your snook matches only a single choice in the table, there was but a single snook of that size in the data. Finally, the longest snook is not necessarily the heaviest snook. Size and weight vary in snook just like they do in humans-a six-foot man may weigh 200 pounds, while a five-foot man may weigh 250 pounds. The heaviest snook on the Atlantic coast weighed 37.5 pounds but was only 43 inches; the longest snook was 45 inches and weighed only 35.4 pounds.

As the numbers of lunker snook increase, there will be a greater need for information regarding the size-weight relationship of these fish. Anglers who care to contribute to the development of a more robust table, and even expand the size limits of the relationship, are invited to submit their length and weight data to snook biologists. If enough snook anglers contribute known weight and length data, we will provide the fishing community with a more exact table. You may submit your measured observations to snook biologists at the following e-mail addresses:

ron.taylor@myfwc.com
alexis.trotter@myfwc.com
jim.whittington@myfwc.com

Thank you for your help and continued support! rt

Observed Weights From Known Lengths of Florida's Common Snook