Information on the chemical ecology and bioactivity of chemical compounds present in the sea cucumber Psolus patagonicus is provided through an interdisciplinary approach. The specimens studied were collected from two different and very distant sampling localities: Bridges Islands (Beagle Channel, Ushuaia, 54° 48′57″ S 66° 25′00″ W) at depths of 4 to 10 m by SCUBA diving, and from the scallop beds of Zigochlamys patagonica (39° 27′10″ S 55° 56′76″ W), at depths of 110 m and 115 m (43° 47′84″ S 59° 56′80″ W) by means of non-selective dredge in the South Atlantic Ocean.The secondary metabolites were isolated from complete adults by a combination of chromatographic methods and purified by high-performance liquid chromatography. They were characterized as triterpene glycosides through extensive spectroscopic analyses (nuclear magnetic resonance and fast atom bombardment mass spectroscopy) and chemical methods. A purified fraction containing Patagonicoside A as the main triterpene showed a high level of mortality against the brine shrimp Artemia salina and revealed different antifungal activity of Patagonicoside A and its desulphated glycoside (ds-Patagonicoside A) against the fungi Cladosporium fulvum, Fusarium oxysporum and Monilia sp., compared with a potent commercial antifungal product.

The residency behaviour of six specimens of spangled emperor, Lethrinus nebulosus, was studied by acoustic telemetry in the mooring area (3–6 m depth) of a marine protected area (MPA) in New Caledonia. The 3 smaller fish (34–49 cm FL) remained within the study site less than 6 hours. The 3 larger individuals (51–54 cm FL) were regularly detected within the study site during the survey (6.5 months). These fish followed similar diurnal patterns of detection. They use the study site as a resting area during the day and migrate each night to feeding grounds after sunset. However, their presence was higher when wind speed was low (<10 knots) during weekends and school holidays. These links reflect a possible impact of human feeding activity. Consequently, management policies should include measures to control feeding activities within MPAs to maintain marine communities in a state unaltered by human activities.

From June 2004 to May 2006, 1040 Caranx rhonchus (Carangidae) ranging from 6.5 to 30.6 cm in total length (TL), fished in the Gulf of Gabes (south Tunisia, central Mediterranean), were used to investigate feeding habits of the species. This study was based mainly on the evolution of the index of relative importance (IRI) with respect to sex, fish size and season. Among 1040 stomachs examined, 595 were empty (%VI = 57.2). The vacuity index (%VI) differed significantly across months and declined slightly with season. A total of 13 species representing 12 different families belonging to four major groups: teleosts, crustaceans, molluscs and annelids, were identified in stomach contents of Caranx rhonchus.

Caranx rhonchus is primarily an opportunistic piscivorous fish with a diet characterized by a wide range of species. Teleosts occurred in the majority of stomachs, with a total of the relative importance (%IRI) of 52.7%. The anchovy Engraulis encrasicolus were the most important teleost species (%IRI = 11.2), while crustaceans were the second most important food category consumed (47.1%).

There were no significant differences in the diet between males and females, but significant differences were found with season and among size-classes.

Age and growth of the common guitarfish (Rhinobatos rhinobatos) were estimated from the north-eastern Mediterranean coast of Turkey. A total of 115 common guitarfish (66 females and 49 males) were sampled. Age determinations were carried out using vertebral sections. Alcian blue dying techniques were used to enhance the visibility of the band on vertebrae. The techniques have been used for the first time on elasmobranchs vertebrae successfully in this study. A total of 97 vertebrae of 115 were visible on the vertebral band in this study. Male and female common guitarfish ranged in age from 1 to 15 and 1 to 24 y respectively. Total length ranged from 42 to 147 cm for females and 39 to 124 cm for males.

The relationships between total length (TL) and total weight (TW) were presented as TW = 0.0014*TL3.1672 (R2 = 0.98) for females, TW = 0.0012*TL3.1947 (R2 = 0.98) for males and TW = 0.0012*TL3.1915 (R2 = 0.98) for both sexes. The parameters for von Bertalanffy growth curves were estimated as Linf  = 137.70±9.38 cm, K = 0.159±0.047, to = −2.180 ± 0.90 for pooled data.

Water, carbon, and nitrogen contents were analysed in both juvenile and adult specimens of Diaphus theta, Stenobrachius leucopsarus, and S. nannochir, which are the dominant myctophid species in the subarctic and transition waters of the North Pacific. The relationship between body length and dry weight, carbon content, and nitrogen content of these three species were expressed as double logarithmic equations. The differences in chemical content among the different size-classes of each species may be associated with reproductive biology.

I observed shark mackerel demonstrating multiple search and attack strategies. Strategies were categorized as three distinct types: (1) a linear search by single or groups of fish along reef features; (2) ambush from a stationary position on the seafloor; and (3) ambush from resting schools of co-occurring predators. Together these strategies were consistent with both information-sharing and producer–scrounger models of group foraging and indicate significant flexibility in individual fish foraging behaviour based on proximate conditions.

Food of Seriola lalandi was mainly composed of juveniles of horse mackerel (Trachurus lathami) (%IRI = 99.66) showing the species as carnivorous feeders predating on small pelagic organisms.

This paper presents data on the incidental catch of sea turtles in both the Brazilian exclusive economic zone and adjacent international waters (both areas are located mainly in the south-western Atlantic) by Brazilian commercial pelagic longliners targeting swordfish, tuna and sharks. Data were obtained by on-board observers for 311 trips carried out in 2001–2005, totalling 7385 sets and 11,348,069 hooks. A total of 1386 sea turtles were incidentally captured in the five years (some of them were considered dead at capture): 789 loggerheads (Caretta caretta), 341 leatherbacks (Dermochelys coriacea), 45 green turtles (Chelonia mydas), 81 olive ridleys (Lepidochelys olivacea) and 130 of unknown species. Taking into account the distribution of the fishing effort in the study area and the incidental catch of sea turtles, four regions were highlighted for the analyses: Zone 1 is located off the northern Brazilian coast; Zone 2 is located off the central Brazilian coast; Zone 3 is the region off the southern Brazilian coast; and Zone 4, located in the open sea almost totally within international waters, is the region around a chain of undersea mountains known as the Rio Grande Rise (Elevação do Rio Grande). There is no information on the origin (nesting areas) of the captured olive ridleys, but there is some evidence, obtained through genetic and demographic analyses, that loggerheads, leatherbacks and green turtles inhabiting the open ocean around Brazil originate from nesting areas in several countries. Together with the fact that the south-western Atlantic is fished by longliners again from several countries, this places the conservation of sea turtles in that part of the ocean in an international context. Some conservation actions carried out by Brazil concerning the interaction between pelagic longlines and sea turtles in the study area are described.