SUBJECT: Recent status of the Adriatic ichthyofauna
AUTHORS: Jakov Dulčić and Lovrenc Lipej.
DATE: 10th April 2003

The Adriatic Sea is relatively well studied, with a centennial tradition of biological research. However, new taxa of marine flora and fauna are still being recorded each year, including numerous new first records of fishes have been made in the last thirty years in the Adriatic, including non-described species. The most important reason for the increase in preceived biodiversity of the Adriatic ichthyofauna is possibly the discovery of a large number of species outside their usual area of distribution. This may be due to an increase in the research effort (especially in the southern Adriatic basin), or to the use of newer techniques (visual census, underwater filming, use of narcotics, etc.) which allow the exploration of otherwise inaccessible habitats (Quignard & Tomasini, 2000).

By such methods new species of gobiids were discovered in the last thirty years, such as Speleogobius trigloides, Didogobius schlieweni and Gobius kolombatovici, all in the Northern Adriatic area (see works of Miller, Kovačić, Ahnelt, Patzner, Zander & Jelinek and others). Most new records made using these newer techniques are of the cryptobenthic fishes, those that always live inside burrows (such as caves, cavities, holes, clefts) or below cover (stones, boulders, shells) and are therefore not visible from above (Miller 1979, 1996; Patzner, 1999). Recently adopted techniques, such as visual census, non- destructive diving (Harmelin, 1987; Harmelin-Vivien & Francour, 1992), and the use of narcotizers, enabled recording of some apparently “rare” benthic fish species in the Adriatic.

However, few Adriatic institutes are currently using such techniques, and the majority of ichthyologists are unfortunately, only interested with economically important fish species. The mentioned increase in number of species is certainly correlated with climatic and oceanographic changes and to a lesser extent to biological invasion, as well. During the last decade, several papers have been published on the occurrence of new fish species in the Adriatic Sea, bringing up a number of the Adriatic fish species to 430, belonging to 118 families. Some of almost 30 new species to the area can be attributed to the northward spreading of southern, thermophilous species such as Thalassoma pavo, Xyrichthys novacula and especially, Sparisoma cretense. Up to date, seven species of Lessepsian migrants were recorded in the Adriatic.

Paradoxically, the Adriatic sea considered by many scientists as a pioneer area in ichthyological research with centennnial tradition, seems to be, at least at some levels, rather scarcely studied.

A contribution by:

Jakov Dulčić,
Institute for Oceanography and Fisheries, Split, Croatia

Lovrenc Lipej, Marine Biology Station, Slovenia