A hundred years ago, a simple farmer named George Perry caught the biggest largemouth bass on the record. The monster weighed 22.3 lbs (10.1 kg) and fiercely fought the apprentice fisherman until its last breath. Catching such a trophy is every fisherman’s dream, but how long does it take for this species to reach this size?
Largemouth bass can grow as fast as 2lbs (0.9kg) in the first year, but their annual growth decreases to 0.5lbs (0.2kg) in subsequent years. This growth rate is correlated with optimal environmental factors. Gender, weather, habitat, and food supply will also influence these fish’s annual growth.
But even at this optimal growth rate, reaching the size of George Perry’s beast would take about…41 years! Could this fishing feat ever be replicated, or was this giant a unique catch in human history? Let’s find out by digging deeper into the factors contributing to the largemouth growth, including environmental conditions, food supply, and species characteristics.
How Environmental Factors Influence the Growth of Largemouth Bass
A few environmental conditions need to be reunited to benefit the largemouth bass optimal growth.
Let’s take a look at the most critical factors that affect the growth rate of this species.
Water Temperature Requirements
Water temperature plays the most important role in the growth of the largemouth bass.
But depending on the life stage of the largemouth bass, water temperature requirements differ:
- Optimum range for adult growth is between 75-86℉ ( 24-30°C).
- Optimum range for fry growth is between 80-86℉ ( 27-30°C).
- Optimal survival range for eggs and embryos is between 50-86℉ (10-30°C).
- Optimum range for spawning and incubation is 68-70℉ ( 20-21°C).
In colder environments, the rapid growth of the fry is indispensable for their survival. If they get through their first winter, their growth will be positively correlated with water temperature during the hottest months of the year (June-August).
Here, you can take a look at the figure below, which clearly shows the relationship between temperature and growth rate of the largemouth bass:
However, keep in mind that these optimal water temperature ranges may not be met in all lakes inhabited by largemouth bass. Temperature and winter duration, combined with factors such as habitat requirements and food availability, will strongly influence the growth of largemouth bass.
This leads to the second and third most important factors in the growth rate of this species.
The largemouth bass is native to North America -United States, Canada, and northern Mexico- but has also been introduced to other parts of the world. They reside in all types of water -swamps, ponds, lakes, reservoirs, streams, estuaries, and large rivers.
They grow faster in new lakes than in old ones and prefer larger ponds of water to small ones. Habitats favoring the rapid growth of largemouth bass have low current and moderate water clarity. Indeed, largemouth bass prefer shaded areas and seek protection from light at all stages of their life.
The best lakes for finding largemouth bass have shallow shoreline areas and lots of submerged vegetation. For example, the largemouth bass of Sammamish Lake, in the state of Washington, thrives in shallow water, where there is a lot of aquatic vegetation and silt and sand substrate.
Food Supply Requirements
As mentioned above, the growth rate is generally faster in large bodies of water than in small ones. This is because of the density and food intake that can be found in larger bodies of water.
Young largemouth bass eats baitfish, small shrimp, and insects. Adults prefer little fish, frogs, worms, crayfish, snakes, salamanders, bats, and even small animals like mammals and turtle hatchlings.
If a forage population is made up only of large organisms, small bass can be undernourished. On the other hand, when bass feed on large organisms, they only eat one, so the daily food intake of small bass can be high, while that of big bass is small.
The growth of largemouth bass is also very dependent on population density.
Let’s take a lake where we find an abundance (density) of fish of the same species. They will have to compete with each other to be able to feed themselves adequately. On the other hand, if the fish density is low, the competition will be less fierce, there will be more food, and the growth rate will inevitably be faster. The maximum sizes will also be higher.
Other Characteristics Contributing to Largemouth Bass Growth
There are two subspecies of the largemouth bass: the Northern and Florida strain.
Northern subspecies are generally found in the Great Lakes, Mississippi, Florida, and coastal watersheds from Georgia to Virginia. The Florida subspecies are located in Florida and parts of Georgia.
Northern largemouth bass will rarely reach more than 10 lbs (4.5 kg), while Florida bass can potentially reach 20 lbs (9.1 kg) or more. The two subspecies have a similar growth rate during their first three years. Still, the Florida largemouth will exceed the growth rate of the Northern subspecies after that.
Another difference between the two subspecies is tolerance to cold water. The Northern largemouth is cold acclimatized and can even be caught by ice fishermen. The Florida strain is unable to survive prolonged periods of cold water.
The growth rate is also generally higher in the southern regions. For example, in California waters, larger specimens are present because it is more difficult to capture them, and they live longer than southern subspecies. In cold climates, the southern subspecies don’t seem to survive as well as the northern subspecies.
Another characteristic that influences growth rate is the gender of largemouth bass.
Growth rates vary widely between males and females, but females are generally larger than males. They also tend to live longer.
Since males mature faster, breeding pairs often consist of a smaller male and a larger female.
Females of the Florida strain also tend to grow at a rate correlated with a warm climate. Still, males exhibit a growth rate approximately that of a population of the Northern strain.
How To Tell the Age of a Largemouth Bass
Now that you know the main factors contributing to the largemouth bass growth, you might be wondering how to determine the age of the monster you just caught.
There are two ways to find out (and one is slightly more accurate than the other).
Count the Rings
The first method is to count the number of annuli on the scales of the largemouth. But what exactly are annuli? Think about the growth rings in the trees.
Indeed, determining the age of a fish is similar to aging a tree -you just need to count the number of rings. In the case of fish, the growth rings are called annuli, and the spacing between the rings is proportional to the fish’s growth. To do that, you can follow this simple procedure:
- Remove about 10 scales. Use a knife and cut above the lateral line.
- Place the scales between two glass slides.
- Use a microscope to count the number of annuli. If you don’t have a microscope on hand, a simple magnifying glass will do.
However, even if this method is relatively straightforward and non-lethal, it is not the most accurate.
Look for the Otolith
Another way to estimate the age of the largemouth is by removing the otolith (ear bone).
The otolith has annual growth bands, which allows determining the age of the fish more accurately. However, be aware that the fish also needs to be sacrificed to retrieve the otolith, which is not the case with the annuli method.
Even if you become a master at determining your fish’s age, don’t expect to catch a 41- year-old largemouth bass anytime soon. Indeed, biologists estimate that the average life expectancy of bass is 10 to 16 years.
George Perry’s beast was either a dinosaur or a largemouth that grew tremendously during its lifetime. Either way, keep in mind that the average size of largemouth is 12.1 lbs (5.5 kg), which is still considered a trophy bass!
Under the best conditions, largemouth bass grows fast and well. Hitting two pounds in the first year is indeed impressive. Still, this optimal growth rate is heavily influenced by various factors, such as:
- Water temperature
- Food supply
- Characteristics of the subspecies
In all cases, the growth rate is highest in the first year and decreases each year after that.
- IGFA: World Record Holders
- Wikipedia: Largemouth Bass
- American Fisheries Society: Effect of Air Temperature on Growth of Largemouth Bass in North America
- PubMed.Gov: Growth and physiological responses in largemouth bass populations to environmental warming: Effects of inhabiting chronically heated environments
- Taylor & Francis Online: Patterns of Diet and Growth in Co-occurring Populations of Largemouth Bass and Smallmouth Bass
- FAO: Synopsis of Biological Data On the Largemouth Bass
- Bass Resource: Ponds, Climate and Largemouth Bass Growth
- Fecpl: Comparative thermal biology and depth distribution of largemouth
bass (Micropterus salmoides) and northern pike (Esox lucius) in an urban harbour of the Laurentian Great Lakes
- Fisheries and Oceans Canada Library: Biological Synopsis of Largemouth Bass (Micropterus salmoides)
- Fisheries and Oceans Canada: Largemouth Bass (Micropterus salmoides)
- School of Forest Resources & Conservation: Growth and Mortality of Largemouth Bass in Florida Waters
- Michigan State University: Determining the Age of Fish