This table contains relationships for the conversion of one length type to another for over 2,000 species of fish, derived from different publications, or from fish pictures. The relationships, which always refer to centimeters, may consist either of a regression linking two length types, of the form:

Length type (2) = a + b × Length type (1)          …1)

or of ratio b’ , viz

Length type (2) = b’ × Length type (1)               …2)

The available length types are, as elsewhere in FishBase,

TL = total length;

FL = fork length;

SL = standard length;

WD = width (in rays);

OT = other type (to be specified in the Comment field).

When a version of equation (1) is presented, the length range, the number of fish used in the regression, the sex and the correlation coefficient are presented, if available.

When a version of equation (2) is presented, the range and the correlation coefficient are omitted, as the ratio in (2) will usually be estimated from a single specimen, or a few fish covering a narrow range of lengths.

Sources are presented in either case, through a MainRef or, for ratios, by reference to one or several fish pictures.

You get to the LENGTH-LENGTH table by clicking on the Biology button in the SPECIES window, the Population Dynamics button in the BIOLOGY window, and the L-L relation button in the POPULATION DYNAMICS window. The internal name of this table is POPLL table.

On the Internet, you can access this table by clicking on the L-L relationship link in the ‘More information’ section in the ‘Species Summary’ page.

Crispina Binohlan, Rainer Froese and Daniel Pauly