In the present paper, we report the collection of a specimen of the West central Atlantic Stegastes variabilis in the shores of Israel, eastern shore of the Mediterranean. This record was preceded by a record of this species from Malta, in the central Mediterranean. The present record suggests that S. variabilis has established a small population in the Mediterranean.

Chromis chromis is one of the most abundant fish species on the Mediterranean rocky shores. Acting as a by-pass of nutrients from the pelagic to the rocky littoral system, it plays an important role as a resource provider and has a relevant function in the community assemblage. Chromis chromis has many of the characteristics required of an indicator species (e.g. it is easy to recognize in the field, small sized, widespread and abundant). In this study we focused on individual size, sex-ratio and body condition in a damselfish population occurring in a central Mediterranean marine protected area. Fishing trials on a monthly basis (April–November) allowed us to assess seasonal changes in population structure. Fish were measured and weighed and a subsample was aged and sexed. On average, males were larger than females. The allometric coefficient, b, for the whole population was 2.99; the maximum age recorded was 7.5 yr. Before reproduction sex-ratio was close to parity (M:F 1:0.78), while a larger proportion of females was captured during the reproductive period. In conclusion, our results show that the population dynamics of C. chromis is influenced by both sex and size. Since males and females have different behavioural strategies, and since the length of the spawning period is shorter in the smaller than in the larger-sized individuals, this is reflected in temporal changes observed in the population structure.

The stomach contents of 50 Cortez damselfish Stegastes rectifraenum captured at Los Frailes, Baja California Sur, Mexico were analysed to describe their diet. According to our results, S. rectifraenum is an omnivorous species with a preference for certain prey; invertebrates (benthic copepods) and algae (Bryopsis spp. and Ectocarpus spp.). Other animal components (Cerithium spp. and Olivella spp.) can also be found in their diet. No differences were observed between genders (analysis of similarity (ANOSIM), R = 0.002, P = 0.001) or among seasons (ANOSIM, R = 0.046, P = 0.001), therefore their food can be available all year at the rocky reef at Los Frailes.

Larvae of the coral reef damselfish Acanthochromis polyacanthus (Bleeker) were fed either unenriched Artemia nauplii or nauplii which had been enriched by pre-feeding with microcapsules containing either squid oil (SQO) or cod liver oil (CLO). Enriched nauplii contained elevated levels of the n-3 highly unsaturated fatty acids (HUFA) eicosapentaenoic acid (EPA; 20:5n-3) and docosahexaenoic acid (DHA; 22:6n-3) which made up 5.22 ± 0.34 and 2.62 ± 0.28 %, respectively, of total fatty acids in nauplii enriched with CLO, and 10.48 ± 0.36 and 3.43 ± 0.33 %, respectively, in nauplii enriched with SQO. In contrast, unenriched nauplii contained EPA (5.03 ± 1.04 %) but did not contain DHA. Survival differed significantly between treatments over the 18-d study; larvae receiving CLO enriched nauplii showed 100 % survival and those receiving SQO enriched nauplii showed 93.3 ± 6.6 % survival. In contrast, only 46 ± 6.7 % of larvae receiving unenriched nauplii survived to the end of the 18-d study. Wet weight, dry weight and proximate biochemical composition did not differ significantly between treatments at the end of the study. Mean standard length of larvae fed CLO enriched nauplii was significantly smaller than that of larvae fed SQO enriched nauplii; however, neither differed significantly from larvae fed unenriched nauplii. The fatty acid composition of A. polyacanthus larvae was significantly influenced by the fatty acid composition of the diet. The results indicate that A. polyacanthus larvae are unable to synthesise DHA from available dietary precursors and, as such, dietary DHA is required to maximise survival. Development of appropriate culture techniques for the larvae of coral reef fishes will allow controlled laboratory studies with these species and may eventually reduce pressure on wild populations exploited for the aquarium trade.