This table presents information on maximum length (Lmax ), weight (Wmax) and age (tmax) from various localities where a species occurs. The largest values from this table are also entered in the SPECIES table. The POPCHAR table also indicates whether the Lmax, Wmax and tmax values or various combinations thereof refer to the same individual fish.
Plotting histograms of the frequency of species against their maximum length, and interpreting the results seems to be a rather straightforward thing, but it is not. Thus, to be interpretable, histograms must have constant class intervals (here of length), and the number of classes must be neither too low, nor too high (i.e., 15-30, see Sokal and Rohlf 1995). The maximum length of fishes, however ranges from 1 cm (in e.g., gobies) to 14 m (in the whale shark Rhincodon typus), and using class intervals of, e.g., 50 cm (which would generate a suitable number of classes) would cause most fish species to occur in the smallest class, with most others being empty. [Note that we multiply maximum lengths by 1.1 when they were expressed as SL, to make them better comparable with FL and TL; the other length types remain unmodified.]
Using log(length) leads to a graph (see Fig. 16) far more interesting than its linear version: this generates what appears to be normal distributions of log(numbers) vs. log(length), with modes characterizing fishes in general (the typical fish species reaches a maximum length of about 25 cm; see peak of upper curve) and any group of interest (bold line).
We have never before seen plots of this kind for fishes, and we look forward to your opinions on their interpretation and potential applications.
Reference
Sokal, R.R. and F.J. Rohlf. 1995. Biometry. 3rd ed. W.E. Freeman, San Francisco. 887 p.
Daniel Pauly
The table contains over 1,800 records for over 1,000 species extracted from over 500 references.
FishBase users may consider this our answer to the Guinness Book of World Records (Foot 2000). We anticipate many ways for the data in this table to be used, e.g., for testing hypotheses from life-history theory.
Fig. 16. Length distribution of tropical fishes vs. all other species in FishBase.
You get to the POPCHAR table by clicking on the Population dynamics button in the BIOLOGY window and the Max. Sizes button in the POPULATION DYNAMICS window.
On the Internet version of FishBase, click on the Max. age & size link in the ‘More information’ section of the ‘Species Summary’ page to access the POPCHAR table.
Foot, T. 2000. Guinness Book of World Records 2001. Guinness World Records Ltd, 284 p.
Crispina Binohlan and Daniel Pauly