Induction of hypochromic macrocytic anaemia in Oreochromis hybrid (cichlidae) exposed to 100mg/l (sublethal dose) of aluminium

The haematology of Oreochromis hybrid locally cultured for human consumption was investigated after exposing the fishes for 8 weeks to a sublethal dose of 100mg/L aluminium. The haematological changes based on the examination of blood variables during the 2, 4, 6 and 8 weeks of exposures have been reported. The physiological changes brought by the sublethal dose of aluminium in Oreochromis hybrid direct towards a normochromic microcytic anaemia which gradually progresses upon prolonged exposure to a normochromic macrocytic one, eventually becoming hypochromic macrocytic after 8 weeks (long term) exposure. In this instance, these changes have been attributed to the swelling of the red blood cells, haemodilution and impaired haemoglobin synthesis as a result of persistent low haematocrit and haemoglobin concentration recorded.Keywords: Oreochromis hybrid, fish, anaemia, aluminium, sublethal, haematology

Discovery of New Hydrothermal Activity and Chemosynthetic Fauna on the Central Indian Ridge at 18°–20°S

Indian Ocean hydrothermal vents are believed to represent a novel biogeographic province, and are host to many novel genera and families of animals, potentially indigenous to Indian Ocean hydrothermal systems. In particular, since its discovery in 2001, much attention has been paid to a so-called ‘scaly-foot’ gastropod because of its unique iron-sulfide-coated dermal sclerites and the chemosynthetic symbioses in its various tissues. Despite increasing interest in the faunal assemblages at Indian Ocean hydrothermal vents, only two hydrothermal vent fields have been investigated in the Indian Ocean. Here we report two newly discovered hydrothermal vent fields, the Dodo and Solitaire fields, which are located in the Central Indian Ridge (CIR) segments 16 and 15, respectively. Chemosynthetic faunal communities at the Dodo field are emaciated in size and composition. In contrast, at the Solitaire field, we observed faunal communities that potentially contained almost all genera found at CIR hydrothermal environments to date, and even identified previously unreported taxa. Moreover, a new morphotype of ‘scaly-foot’ gastropod has been found at the Solitaire field. The newly discovered ‘scaly-foot’ gastropod has similar morphological and anatomical features to the previously reported type that inhabits the Kairei field, and both types of ‘scaly-foot’ gastropods genetically belong to the same species according to analyses of their COI gene and nuclear SSU rRNA gene sequences. However, the new morphotype completely lacks an iron-sulfide coating on the sclerites, which had been believed to be a novel feature restricted to ‘scaly-foot’ gastropods. Our new findings at the two newly discovered hydrothermal vent sites provide important insights into the biodiversity and biogeography of vent-endemic ecosystems in the Indian Ocean

Behaviour and habitat of the Indian Ocean amphibious blenny, Alticus monochrus

Alticus monochrus Bleeker is an amphibious blenny that inhabits exposed and  moderately exposed rocky shores of Mauritius and other islands of the southwestern Indian Ocean. It remains above the water line on moist or wet substrata over which it migrates vertically and/or horizontally with the tide. Rapid terrestrial locomotion is accomplished by leaping during which the entire body leaves the substratum. When chased into water, it immediately re-emerges. A. monochrus feeds on emerged  microscopic algae scraped from the rocks. An ethogram based primarily on field observations is presented. Although A. monochrus performs all feeding, reproductive and agonistic behaviours in air, and consequently is one of the most terrestrial intertidal fishes, its behaviour patterns are similar to those described for other intertidal blennies.Key words: Blenniidae, behaviour, ethogram, fish

Life history characteristics of Alticus monochrus , a supratidal blenny of the southern Indian Ocean

The blenny Alticus monochrus Bleeker inhabits exposed rocky shores of Mauritius and other islands of the southwestern Indian Ocean. A. monochrus is an amphibious species and remains almost exclusively above the water line, migrating vertically with the tide while feeding on a thin algal layer scraped from the moist substratum. Spawning activity peaks were observed at Pointe aux Caves, Mauritius, during the full moon periods of October and November and two corresponding oocyte size cohorts were identified in excised ovaries collected over the breeding season. Larvae hatched in approximately four days and otolith ring counts showed that settlement occurred 28 days later. Initial post-settlement growth was rapid but growth rate in length declined linearly beyond 50 mm. Length frequency time series showed that the 1991 cohort reproduced at age one, but that none of this cohort survived into the 1993 breeding season, consistent with annual semelparity. By contrast, other expected correlates of semelparity were not observed: fecundity in A. monochrus was lower than in some iteroparous blennies, and there was no obvious physical deterioration of adults following the breeding season, despite their high mortality rate.Keywords: Blenniidae, age, growth, ecology, amphibious, fis

Effect of different light regimes and predation on the sexual behaviour of the Guppy, Poecilia Reticulata (Pisces, Poeciliidae)

No Abstrac

Global introductions of crayfishes: Evaluating the impact of species invasions on ecosystem services

10.1146/annurev-ecolsys-111511-103919Annual Review of Ecology, Evolution, and Systematics43449-47