Growth Rate of Adult Great White Sturgeon in the Fraser River
(from 100cm to 200cm in length)
As with most all of the animal kingdom, growth rates are higher in the juvenile phase of life. The White Sturgeon is no exception. Many studies have shown the pre-reproductive years include a significantly higher average growth rate. In order to estimate the age of a sturgeon, it is important to know how the growth rates change over the lifespan of this magnificent fish.
White Sturgeon Guide / conservation advocate, Yves Bisson, has tagged and / or recorded approximately 20,000 White Sturgeon over the past 20 years in the Lower Fraser River & tributaries in British Columbia. The data collected has been used for numerous studies, including the calculation of growth rates in this report.
A general rule in the White Sturgeon community is that a juvenile is below 100cm, and an adult White Sturgeon is anything over 100cm in length, measured from nose to tail fork, along the medial line. Based on calculations done, the age of a White Sturgeon at 100cm averages 15 years of age.
White Sturgeon Age of Maturity
The accepted age of maturity for a White Sturgeon ranges based on literature.
Based on the Department of Fisheries & Oceans Canada, the spawning age is around 15 years of age for males, and 20+ years for females ref.
The California Department of Fish and Wildlife states that White Sturgeon are said to be 10 – 16 years old before being able to reproduce (with males maturing earlier than females). ref
The British Columbia Ministry of Environment, Lands and Parks indicate an age of between 15 and 30 years before reaching sexual maturity. ref
Taking into account these sources above and other sources and local knowledge, an estimate of 15 years and 100cm in length should be a good guess as to when a White Sturgeon reaches a reproductive age.
Key Results
The average growth rate of the Fraser River Great White Sturgeon between 100 and 200cm was 4.4 cm per year ± 1.5cm/yr (2.9 to 5.9cm/yr). While the growth rates can be assumed to lessen over time (and therefore more logarithmic than linear), a linear model fit well (a 0.968 correlation coefficient).
| Measured | Parameter |
| 4.4 | Avg growth rate (cm/yr) |
| 1.5 | Standard Deviation (cm/yr) |
| 9.1 | Max growth rate (cm/yr) |
| 1.5 | Min growth rate (cm/yr) |
| 4.2 | Median growth rate (cm/yr) |
| 52 | Number fish used in study |
| 495 | Number measurements |
| 9.5 | Avg # measurements per fish |
The following chart shows the summarized growth rate of Adult White sturgeon between 100 & 200cm, as a function of age, with upper and lower one standard deviation (67% of the sturgeon should fall within this range).
As a quick measurement in the field, an average Young Adult White Sturgeon grows 1.5 inches per year and reaches 200cm at age 38.
Growth Rate of Adult White Sturgeon – Comparison with Published Data
Results from this study of Fraser River Adult White Sturgeon below 200cm in fork length compare well with data from the Department of Fisheries & Oceans, who state that the average White Sturgeon grows at approximately 5cm/yr from 5 to 25 years of age, then 3cm/yr from 150 to 170cm (Ref 2: Life Cycle of A White Sturgeon)
Growth rates from a common white sturgeon growth chart used in the industry shows a fairly aggressive growth rate in comparison to what was found in our study. This Growth table starts at 94 cm, with a 7.3cm/year growth rate, compared to a more modest 4.4cm/year in this present study between 100cm and 200cm.
The most aggressive growth rate reported was from OregonFishingInfo.com, where the Columbia White Sturgeon is said to grow by 4 inches (10cm) per year up to 3ft, then 3 inches (7.5cm) per year until maturity. The Fraser River fish measured in this study showed a much lower growth rate.
In 1963, a comprehensive study of the Age and Growth of the White Sturgeon in the Fraser River was put together by Masters Candidate, Saul Nelson Semakula for the department of Zoology at UBC.
Mr Semakula studied mainly juvenile sturgeon, with the majority being caught in salmon nets in New Westminster, or by gill nets at the Dewdney Slough near Mission. Growth rates were determined by establishing a relationship between the growth of the first pectoral fin ray and the fork length of the fish, then back-calculated to calculate growth at particular years, much like rings in a tree. It was found that the females grow much faster than males after the age of 16, however the number of samples above 100cm was very limited.
The chart below compares the literature results with the measured results from the current study.
Conclusions – Growth Rates of Adult White Sturgeon
As was expected, as the White Sturgeon reaches maturity, the growth rate slows. But the sturgeon continues to grow. Between 100 and 200cm in length, the growth rate was reduced from 5.2 to 4.4cm/year.
Assuming a sturgeon reaches 100cm at age 15, it will be 38 when it reaches 200cm in length. This is only an average, and actual values can very considerably depending on the fish.
White Sturgeon Growth Rates
