The Grayling Research Trust

Grayling Weight Survey

The GRT has launched a project to record the length and weight of grayling. The length/weight (condition factor) of a grayling may vary across the country/continent. There will be seasonal variation, as fish lose and gain weight depending on the food availability and the onset of spawning. This study is being undertaken because there is little information on the condition factor of grayling. It is hoped that the findings from this study will be used to gain a better understanding of grayling populations. To make reporting fish lengths and weights easy, a short submission form is available below or simply tweet (@GRT_Updates or #graylingweight).

Please fill in all required fields:


Fulton's condition Factor

Fulton’s condition factor is a measure of an individual fish’s health that uses standard weight.

As fish grow in length, they increase in weight. The relationship between weight and length is not linear. The relationship between length (L) and weight (W) can be expressed as: W = aL^b\!\, where W is the whole body wet weight in grams and L is the length in centimeters; the factor 100 is used to bring K close to a value of one.

Fulton's condition factor is used as a basis for comparison to assess the health of an individual or group of fish.

Generally, fish that are heavier than the standard weight for their length are considered healthier, having more energy reserves for normal activities, growth and reproduction.

Generally, fish that are less than the standard weight for their length are considered in poor health, having less energy reserves for normal activities, growth and reproduction. Possible reasons for a poor Fulton's condition factor maybe the lack of food/prey, increased competition, habitat unsuitability or an infection.

To calculate the condition of your grayling your fish weight needs to be in grams, we have developed the tool below to convert weights in pounds into grams. Enter your weight and click calculate.

Weight converter tool

Pounds: Ounces: Grams:

To calculate the condition of your grayling enter your values into the boxes below and click calculate.

Condition calculator tool

Weight (grams):
Length (mm):

Fulton's Condition Factor:
This Means: