The present study aims to apply a growth model to a species with a conditional reproductive strategy, the grass goby Zosterisessor ophiocephalus (Pisces: Gobiidae), in order to evaluate the adoption of alternative tactics by this species under the constraints of different dates of birth. The model describes the growth pattern (based on age, weight and gonadosomatic index data) of an individual, assumed to be representative of a given cohort, while also taking into account the energetic loss due to parental care. The most important parameters have been calibrated by comparing the results with a set of data collected in the lagoon of Venice. The comparison between the growth pattern of a parental male and that of a late-born male suggests that the birthday could be one of the major constraints affecting the adoption of an alternative tactic during the first breeding season.

Lights were attached to the headline of a bottom trawl during a series of tows at 1000 m depth in the Rockall Trough (north-east Atlantic). There was no significant difference in the overall numerical abundance of demersal fish between the trawl catches with light and the controls with no light. A principal components analysis based on the total fish catch between the experimental and the control stations showed no segregation. At the individual species level significant differences in catch rate were found for eight species. These are discussed in relation to the small amount of available information on the visual systems of deep-sea demersal fish and their diet.

The distribution and bathymetric zonation of deep-sea ophiuroids off the Japanese Pacific coast were analysed. Samples were collected using beam trawls between depths of 60 and 6382 m. In 154 samples, 139 ophiuroid species were found. Data were clustered based on Morisita–Horn similarity index and a dendrogram was constructed. The Japanese Pacific coast can be divided in two major zones. One in the northern part off the Japanese Pacific coast, and another in the region off the central Japanese Pacific coast. In the northern region, five bathymetrical zones were detected at depths of 130–250, 300–500, 500–650, 1100–1500, and 2000–3000 m. In the central region, eight bathymetrical zones were detected at 100–140, 150–250, 200–300, 220–300, 300–400, 400–500, 800–1000, and 1000–1500 m depth. Representative species for each bathymetrical zone are reported.

Eicosatetraenoic acid (20:4(n-6)), a polyunsaturated fatty acid (PUFA), was found in deep-sea holothurians at a depth of nearly 5000 m in the temperate north-east Atlantic. It has been suggested that deep-sea animals may be able to synthesize this compound de novo. Since this fatty acid is typical of Rhodophyceae, which has previously been found incorporated in gelatinous material captured in the deep sea, an alternative origin of this fatty acid in the deep-sea holothurians is proposed.

Anchovy larvae, collected at 107 stations in the north-west Mediterranean were analysed, in relation to three possible variables, the diurnal or nocturnal time of sampling, the location of sampling stations in relation to the neritic and oceanic domain, and the assignation of anchovy samples to each of the two main anchovy spawning grounds in the region. Feeding activity appeared to be mainly diurnal, stomach contents consisting mostly of copepod eggs, nauplii and copepodites. The stomachs of larger larvae showed an increase in the size range of prey, together with a parallel increase in the incidence of copepodites in the diet.

The beryciform fish Hoplostethus mediterraneus is a species discarded from the southern Portuguese coastal fisheries. It is taken as by-catch by deep water trawls, at depths of between 234 m and 618 m. This species is a benthopelagic feeder, preying mainly on crustaceans. The dominant prey species encountered were the euphausid Meganyctiphanes norvegica and the amphipod Anilocra physodes. It seems that H. mediterraneus is an opportunistic rather than a selective feeder.