Freshwater Fishes of Iran
Introduction - Purpose
This work is meant to provide a guide to the freshwater fishes of Iran. There are no modern keys to this fauna, some available books are incomplete or cursory treatments or outdated, and the detailed and diverse scientific literature is widely scattered in time, languages and journals. Iran lies at a region of major zoogeographical interchange and has a diverse and interesting ichthyofauna about which comparatively little is known. An accurate identification is a pre-requisite for further scientific studies and this website aims to serve that purpose and to be an introductory guide to the fishes. The guide is aimed at a mixed audience, including scientists familiar with ichthyology to whom some introductory sections of this work will be superfluous, and those whose knowledge of fishes is embryonic or who may have limited access to literature sources.
This work has been carried out over a period of 40 years from my first studies on Iranian fishes in 1971 at the University of Ottawa on collections made by V. D. Vladykov along the Caspian coast, continuing during a three-year residence in Iran from January 1976. In that year, 7 articles were published strictly on Iranian fishes (3 on parasites, 1 on pesticides, 1 on fisheries, 1 describing the blind white fish and 1 a summary of the latter; 2 were in Farsi). In 2006, 160 articles on Iranian fishes appeared, along with many relevant works from neighbouring countries, works on the aquatic environment in Iran and works on taxonomy and systematics relevant to Iran. The study of fishes is now a very active field within Iran and the Middle East. Accordingly, 2010 is the last year that this work is updated although some systematic and taxonomic studies may still be incorporated.
Literature on fishes of Iran can be found in Zoological Record (Pisces) and at http://www.sid.ir/En/Index.asp which has lists of publications in Iranian journals and abstracts, both in English, as well as in Farsi.
The Introduction contains several explanatory sections. These sections include detailed methods of counting and measuring characters, an explanation of scientific names of fishes, details of fish structure so that keys can be readily understood, ways of capturing and preserving fishes and recording the all-important collection data, and how to identify fishes. This introductory part also includes a brief review of the history of research on Iranian fishes and descriptions of the environment including geography, climate, habitats, environmental change and drainage basins.
The bulk of the text is the "Species Accounts" which serve to identify, describe and map the distribution of each species. Families of fishes follow Nelson (2006) with genera and species arranged alphabetically within each family. Each Species Account is comprised of the following parts: the scientific name, common names, sections on systematics, key characters, morphology, sexual dimorphism, colour, size, distribution, zoogeography, habitat, age and growth, food, reproduction, parasites and predators, economic importance, conservation, further work, sources, and an illustration and a distribution map.
The biological information may be cursory. Many species are poorly known and their biology has not been studied, especially within Iran. Some information is available for species shared with Turkey and Iraq and I have tried to incorporate this literature as being less well known or accessible. Many Caspian Sea basin species are shared with Europe and the former U.S.S.R., are comparatively well-known and have an extensive literature, often summarised in books, bibliographies and synopses. It is not known in many cases if their biology in Iran is similar. Iranian populations are often referred to distinct subspecies and occur at the southern limit of the species range. Only a brief, summary account of their biology is therefore given from synoptic literature sources. Biological information generally is a brief summary of literature and readers should consult the original papers for more details.
Some anecdotal biological information is added from my field collections where spawning individuals were noted or gut contents examined superficially. Most fish spawn in the spring. Feeding habits can often be deduced from morphology. Fish with an arched and ventral mouth, horny jaw edge, elongate gut and black peritoneum are feeders on detritus and aufwuchs scraped from rocks. Most fish with a simple, s-shaped gut feed on invertebrates such as crustaceans and aquatic insect larvae. A few fish with molar pharyngeal teeth have a diet of molluscs whose shells are crushed by the heavy teeth. Some fish are piscivorous and have an appropriate jaw shape and streamlined appearance suitable for catching and holding their fish prey. Fish with elongate and numerous fine gill rakers filter phytoplankton or zooplankton from the water column. Very few fish feed on macrophytes (large plants).
"Checklists" summarise the diversity of the ichthyofauna. "Glossaries" explain both ichthyological terms for those new to the science and Farsi and geographical terms for those unfamiliar with that language. A "Bibliography" comprises books and papers referred to in the text and other relevant works, which form a good general basis for the serious student of Iranian freshwater fishes.
© Brian W. Coad (www.briancoad.com)