%BWD : a measure of the dry weight of feed provided daily to fish held in captivity, in % of their weight.
: "lambda maximum": the wave length of light (in nm) to which the visual pigments in fish eyes are most sensitive.
: "beta": exponent in a relationship linking K1 and W. Also Bunsen coefficient for oxygen.
A : aspect ratio of the fish’s caudal fin, used as index of its level of activity, and defined by h2/s , where h is the height of the caudal fin, and s its surface area.
BL : body length: reference length for the swimming speed of fishes (BL ×
S-1). Also: an undefined measure of length, which may refer to SL, FL or TL.
BMP : generic Windows bitmap files.
B/W : black-and-white: refers here to pictures of fish.
C : parameter of the von Bertalanffy equation, modified to express seasonal growth oscillations, and expressing the amplitude of such oscillations. In practice, C ranges from C = 0 (no oscillations) to C = 1, when dl/dt = 0 at the winter point (WP).
°C : degree celsius, used for expressing temperature.
: calcium carbonate.
CD-ROM: Compact Disc-Read Only Memory; a standard for compact disc used as a digital memory medium for personal computers.
C.V. : coefficient of variation (=standard deviation/mean); often expressed as % of the mean.
D : duration of a larval stage; also, in eggs: time to hatching (in days).
dl/dt : growth rate in length; first derivative of the VBGF for length.
dw/dt : growth rate in weight; first derivative of the VBGF for weight.
: delta t: a time interval or period.
T : difference within an annual cycle of the highest mean monthly temperature (summer) and the lowest mean monthly temperature (winter).
DOS : Disk Operating System.
F : instantaneous rate of fishing mortality (time-1), i.e., F = Z – M. Also: absolute fecundity.
FL : Fork length; the length of a fish, measured from the tip of the snout to the tip of the shortest central rays of the caudal fin.
G : specific growth in weight, defined by where and are successive weights, and the growing period; used for fish larvae;
GIF : Graphic Interchange Format, used to store black-and-white pictures in FishBase;
h : hour, a unit of time. Also: height of a fish’s caudal fin.
: measure of genetic heritability; also height squared of caudal fin, used to compute its aspect ratio.
ha : hectare (100 m x 100 m).
Hg : used to express partial pressure as millimeters of mercury; e.g., in ‘mmHg of oxygen’ (from Latin ‘hydragyrum’ name for mercury, liquid silver).
JPEG : Joint Photographic Experts Group; an image compression standard; a format used to compress color photos.
K : parameter of the VBGF, of dimension time-1, and expressing the rate at which the asymptotic length (or weight) is approached.
: gross food conversion efficiency; ratio of growth increment/food ingested during a given period.
kg : kilogram.
l : liter.
L : symbol for the individual body length of a fish.
: median lethal concentration, i.e., concentration of a substance sufficient to kill 50% of the fish exposed to it during a specified period.
: asymptotic length (also Linf): a parameter of the VBGF, expressing the mean length the fish of a given stock would reach if they were to grow for an infinitely long period.
Lm : mean length at first maturity of the fish of a given population.
Lmax : maximum individual length on record for a species or one of its populations (depending on context).
ln : base e logarithms (also loge).
: base 10 logarithms (also log10).
Lt : mean length at age t predicted by the VBGF.
M : instantaneous rate of natural mortality (time-1), i.e., M = Z - F.
MDA : file extension denoting a Microsoft Access file holding user and security information.
MDB : file extension denoting a Microsoft Access data file.
mg : milligram.
M% : natural mortality in % (as recorded in aquaculture experiments).
s-1 : meter per second: used to express swimming speed of fish.
n : number of specimens used to derive length-weight, fecundity-length, or other relationship, or included on a graph.
NG : not given; refers here to length type.
: size (number) of a population of fish at a given time t.
nm : nannometers (thousandth of a millimeter).
OT : length OTher than FL, SL, TL or WD; used to express size in fish.
pH : a measure of the acidity (pH<7) or alkalinity (pH>7) of a liquid.
ppt : parts per thousand, used to express salinity (though salinity doesn’t really require such symbol).
Ø : a growth performance index, equal to log10 K + 2/3 log10 W¥
, where K and W¥
are parameters of the VBGF.
Ø : a growth performance index, equal to , where K and are parameters of the VBGF.
Q : amount of food consumed by a population of fish over a specified period; also: metabolic rate, i.e., consumption.
: weight-specific oxygen uptake.
Q/B : amount of food consumed per unit weight of an age-structured population of fish; generally expressed on an annual basis.
r : coefficient of (linear) correlation; where appropriate, this refers to linearized variates, e.g., log10 W vs. log10 L.
rm : maximum intrinsic rate of population increase, in year-1. A measure for the resilience of a population to withstand fishing pressure.
RAM : Random Access Memory; a set of chips in the computer in which information can be held for rapid access by the microprocessor.
: daily ration, i.e., the amount of food consumed by a fish of a given weight in one day, and often expressed as % of its own weight.
ROM : Read-Only Memory: a form of computer memory in which information is permanently recorded so that it cannot be erased or changed.
s : second, a unit of time. Also: surface area of a fish’s caudal fin.
S.D. : standard deviation (of a number of variates).
S.E. : standard error (of a mean).
SL : standard length; the length of a fish, measured from the tip of the snout to the tip of the hypural bone, or of the fleshy part of the caudal peduncle (i.e., excluding the caudal fin).
SL/s : standard lengths per second; used to express the swimming speed of fish.
T : temperature (in °C).
t0 : a parameter of the VBGF expressing the theoretical ‘age’ the fish of a given stock would have at length zero if they had always grown as predicted by that equation. The parameter t0 , which usually takes negative values, is often omitted from stock assessment models incorporating the VBGF.
TL : total length; the length of a fish, measured from the tip of the snout to the tip of the longest rays of the caudal fin (but excluding filaments), when the caudal fin lobes are aligned with the main body axis.
tm : mean age at first maturity of the fish of a given population.
: maximum age reached by the fish of a given species or population (i.e., longevity); hence also: age at exit (or de-recruitment) from a population.
tr : Troph, i.e., trophic level
: age at entry (recruitment) into a fish population.
ts : parameter of the VBGF, as modified to express seasonal growth oscillations, and expressing the time difference between t = 0 and the start of a sinusoid oscillation.
VBGF : Von Bertalanffy Growth Function, used to describe the growth in length or weight of fish.
VGA : Video Graphic Array: a graphics display system for computer monitors with a resolution of 640 x 480 pixels at 16 colors. We recommend using at least 256 (better 65,000) colors with FishBase
W : symbol for the individual body weight of a fish.
WD : width; the length, in rays, and skates from the tip of the left to the tip of the right ‘wing’.
WP : winter point: the period of the year, expressed as a fraction, where growth is slowest, i.e., dl/dt = 0 when C = 1.
: asymptotic weight (also Winf): a parameter of the VBGF expressing the mean weight the fish of a given stock would reach if they were to grow for an infinitely long period. Also: the weight corresponding to L¥
Wmax : maximum individual weight on record for a species or one of its populations (depending on context).
Wt : mean weight at age t predicted by the VBGF.
Z : instantaneous rate of total mortality (time-1), i.e., the sum of natural mortality (M) and fishing mortality (F).