When Linnaeus established the binominal system of nomenclature with the 10^th edition of his Systema Naturae in 1758, he laid a strong foundation for taxonomic work: a unique combination of a generic and a specific name had to be assigned (fixed) to a specimen (the holotype), which thus became the ultimate reference point for a biological species. Unfortunately, this beautiful concept was confused by the subsequent acceptance of subspecies, also fixed to a specimen but declared a subunit of a species and thus described by three names (e.g., Oreochromis niloticus eduardianus). The original species then becomes Oreochromis niloticus niloticus and we have the confusing situation that its holotype now points to a subspecies as well as to a species supposed to include all other subspecies. This undermines the widely used biological species concept that explicitly includes populations by defining species as "groups of actually or potentially interbreeding natural populations, which are reproductively isolated from other such groups" (Mayr 1942, p. 120), and thus leaves no space for subspecies (see also Sinclair 1988 for an excellent discussion of marine populations).

Fisheries scientists work with the exploited part of populations which they term ‘stocks’. Similarly, aquaculturists work with ‘strains’, i.e., races or varieties of a certain species. Again, the distinction between a population or ‘race’ and a subspecies is unclear.

For the structure of a relational database, the conceptual confusion between species, subspecies and populations translates into unsatisfactory design.

In the current version of FishBase¾ as in the taxonomic literature¾ a subspecies is treated similarly to a species, i.e., with its own record in the SPECIES table, but with a two-word entry in the specific name field. If a subspecies has been entered then the original species itself also becomes a subspecies (see above). The downside of this approach is that a search for, e.g., Oreochromis niloticus will not find a record in the SPECIES table and the subsequent automatic search for Oreochromis niloticus* will find a total of seven subspecies with Oreochromis niloticus baringoensis being first because of alphabetic sorting; the user has to go through the list to find O. niloticus niloticus as record number five. From a design point of view it would be better to treat a subspecies as a stock or population; however, that would create incompatibilities with the taxonomic literature and create new design problems (e.g., synonyms of subspecies would have to be linked to populations). It probably would be best if taxonomists would make up their mind and either consider the characters of a subspecies distinct enough to raise it to the species level, or consider it a population of a species and synonymize it, as done by Kottelat (1997) for European freshwater fishes.

In order to be able to separate information for a stock or strain from that relating to the species in general, each record in the SPECIES table is linked to one or several records in the STOCKS table (a one-to-many relationship). All biological information that may differ between populations is attached to the STOCKS table and assigned a Level such as: species in general, subspecies in general, wild stock/population, cultured strain, hybrid.

In the CD-ROM version, if FishBase contains more than one stock or strain for a given species, the STOCKS table opens a tabular view with each row describing one stock or strain. Double-click on a row to switch to form view. Alternatively, use the up and down arrows to select a stock and press Enter to switch to form view.

The Stock definition field gives the distributional range for each of the above categories. For strains, it describes the origin and size of the founder stock and its common name. For hybrids, which are attached to the female species, it states the male species and other details. The field also points out doubtful range extensions and common misidentifications.

The Status field describes the status of threat following the categories defined by IUCN: Extinct; Extinct in the wild; Critically endangered; Endangered; Vulnerable; Lower risk; Lower risk: conservation dependent; Lower risk: near threatened; Lower risk: least concern; Data deficient; Not evaluated; Not applicable; Not in IUCN Redlist (Hilton-Taylor 2000). Note that the last two categories were added to accommodate, e.g., hybrids or artificial strains, and the many cases for which we have no information.

Biological information is categorized into Trophic ecology; Genetics; Reproduction; Population dynamics; Fish as food; Morphology and physiology. If a category is represented by a black button, the specific biological information is available (gray buttons represent information gaps).

The related buttons can be used not only to get that information, but also to avoid duplication of research. For a number of species such as Plectropomus leopardus, the buttons largely reflect the actual state of knowledge and thus can be used to identify research gaps. We expect that many of our users will provide us with hints, or reprints to help us cover as many species as completely as possible. Click any of the black buttons to open the respective tables.

To date the STOCKS table contains over 20,000 records, including 72 cultured strains, 9 hybrids and 9 populations/stocks. We expect the latter number to increase once we start incorporating the 160 stocks currently recognized by the International Council for the Exploration of the Sea (ICES), the stocks treated in R.A. Myers’ RECRUITMENT table (this vol.) and, e.g., the trout strains recognized by Kincaid and Brimm (1994).

You get to the STOCKS table by clicking on the Range (for the status of threat of the stock) or Biology (for biological information of the stock) buttons in the SPECIES window.

On the Internet version the fields of the STOCKS table are integrated in the ‘Species Summary’ page.

Hilton-Taylor, C. Compiler. 2000. 2000 IUCN Red list of threatened species. IUCN, Gland, Switzerland and Cambridge, UK. 61 p.

Kincaid, H. and S. Brimm. 1994. National Trout Strain Registry. US Fish and Wildlife Service’s Division of Fish Hatcheries, National Fishery Research and Development Laboratory and Office of Administration - Fisheries, USA. pag. var.

Kottelat, M. 1997. European freshwater fishes. Biologia 52, Suppl. 5:1-271.

Mayr, E. 1942. Systematics and the origin of species. Columbia University Press, New York. 334 p.

Sinclair, M. 1988. Marine populations: an essay on population regulation and speciation. University of Washington Press, Seattle. 252 p.