Animal mimicry: Choosing when to be a cleaner-fish mimic

Mimicry in vertebrates is usually a permanent state — mimics resemble and normally accompany their model throughout the life stages during which they act as mimics. Here we show that the bluestriped fangblenny fish (Plagiotremus rhinorhynchos), which aggressively attacks other coral-reef fish, can turn off the mimetic colours that disguise it as the benign bluestreak cleaner wrasse, Labroides dimidiatus, and assume a radically different appearance. This opportunistic facultative mimicry extends the fangblenny's scope by allowing it to blend into shoals of small reef fish as well as to remain inconspicuous at cleaning station

Biofluorescence as a survey tool for cryptic marine species.

As ecosystems come under increasing anthropogenic pressure, rare species face the highest risk of extinction. Paradoxically, data necessary to evaluate the conservation status of rare species are often lacking because of the challenges of detecting species with low abundance. One group of fishes subject to this undersampling bias are those with cryptic body patterns. Twenty-one percent of cryptic fish species assessed for their extinction risk (International Union for Conservation of Nature [IUCN]) are data deficient. We developed a nondestructive method for surveying cryptically patterned marine fishes based on the presence of biofluorescence (underwater biofluorescence census, UBC). Blue LED torches were used to investigate how widespread biofluorescence was in cryptic reef fishes in the Coral Triangle region. The effectiveness of UBC to generate abundance data was tested on a data-deficient pygmy seahorse species (Hippocampus bargibanti) and compared with data obtained from standard underwater visual census (UVC) surveys. We recorded 95 reef fish species displaying biofluorescence, 73 of which had not been previously described as biofluorescent. Of those fish with cryptic patterns, 87% were biofluorescent compared with 9% for noncryptic fishes. The probability of species displaying biofluorescence was 70.9 times greater for cryptic species than for noncryptic species. Almost twice the number of H. bargibanti was counted using the UBC compared with UVC. For 2 triplefin species (Ucla xenogrammus, Enneapterygius tutuilae), the abundance detected with UBC was triple that detected with UVC. The UBC method was effective at finding cryptic species that would otherwise be difficult to detect and thus will reduce interobserver variability inherent to UVC surveys. Biofluorescence is ubiquitous in cryptic fishes, making this method applicable across a wide range of species. Data collected using UBC could be used with multiple IUCN criteria to assess the extinction risk of cryptic species. Adopting this technique will enhance researchers' ability to survey cryptic species and facilitate management and conservation of cryptic marine species

Ichthyofauna of the rocky coastal littoral of the Israeli Mediterranean, with reference to the paucity of Red Sea (Lessepsian) migrants in this habitat

The ichthyofauna of the shallow rocky habitats was studied at three different localities on Israel's Mediterranean coast, at three sites, Mikhmoret (45 kin north of Tel Aviv), Habonim (60 km north of Tel Aviv) and Rosh HaNiqra (Israel-Lebanese border). In total, 8387 individuals belonging to 79 species and 31 families were collected, including 35 species that were site attached, 23 resident species and 21 visitor species. The cluster analysis showed no significant differences between the three sites. The Euclidean distance was highest when all species were included, but dropped sharply when visitor species were omitted; the difference value was lowest when only benthic, site-attached species were considered. Seven Lessepsian (Suez Canal) migrant species were among the collected visitor species, two were among the residents, and there were none among the site-attached fish. We suggest that the low mobility and demersal spawning habits of the site-attached Red Sea species could hinder their invasion of the Mediterranean, as no continuous rocky habitat connects the northern Gulf of Suez, the Suez Canal and the southern Mediterranean coast of Israel. In addition, the re-colonization process following defaunation was examined. Monitoring of the study sites following the ichthyocide collections was possible in some cases and indicated that fish re-colonization was a fairly rapid process, complete after approximately 12 months, indicating that while single, small size defaunations can provide valuable information on the fish assemblage, they do not appear to cause long-term damage to such habitats