Spatial distribution patterns of two small serranids, Serranus scriba and S. cabrilla, have been investigated in  June 2001 in north-eastern Sardinia (Tyrrhenian Sea, Italy). Density and size of both species were estimated by visual census on shallow (5–7 m) rocky reefs constituted by different mineralogical types (granites vs carbonates), at different locations (several kilometres apart from each other) and sites (hundreds of metres from each other). Serranus scriba was significantly more abundant on granite rocks (where it also showed a greater frequency of large specimens) than on carbonates, while S. cabrilla displayed opposite patterns.

The effect of temperature on growth of butterfish, Pholis gunnellus on the west coast of Iceland was studied from September 1995 to March 1997. Butterfish were collected monthly at two sites with different temperature regimes. According to otolith readings butterfish can reach 12 years. The fish in the area with higher sea temperature were larger at all ages but had similar growth rates. Higher temperature seems to result in a shorter incubation time of butterfish eggs and/or higher growth rate of the larvae, leading to larger larvae size at settlement.

Two Red Sea immigrant fish species, Fistularia commersoni (Fistularidae) and Sphyraena flavicauda (Sphyraenidae), are reported for the first time from the Anatolian coast (Turkey) and for the second time from the Mediterranean Sea. Occurrence of Lagocephalus suezensis (Tetraodontidae) at the southern Turkish coast is substantiated and a new record of this species in the Aegean Sea is presented.

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.

Diel feeding pattern of red mullet in the Hisarönü Bay was studied from samples collected by bottom trawl during a 24-h period in the summer of 1997. Feeding activity of red mullet commenced at dawn and reached its maximum value at noon. During the period between noon to early evening, feeding intensity slowed down and then showed a small increase towards sunset. After sunset, the feeding activity nearly stopped and fish with empty stomachs increased. At night almost all stomachs were empty. Polychaetes, decapods, bivalves and amphipods were the major prey groups in the diet of red mullet and no significant diel variations were observed in the relative importance of these groups.

The occurrence, meristic, length frequency, condition factor, length–weight relationship and day/night differences in catch are reported for a population of cuskeel Ophidionrochei at Duće-Glava (43°26′N 16°41′E, Croatian coast, eastern middle Adriatic) from April 2000 to March 2001. The highest catches in shallow water occurred in June, with a second peak in September and October, and were always at night, indicating this species as nocturnal predator.

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.

The capture of five specimens of Solea (Microchirus) boscanion (Osteichthyes: Soleidae), a species previously unrecorded in the Mediterranean, is reported from the Iberian coast (western Mediterranean). The main morphometric and meristic measurements of this species with data of the other sympatric, and morphologically very similar, soleids Microchirus variegatus and Buglossidium luteum are also given. The record is discussed in relation to climate change and competition between species.

Possible effects of ‘El Niño’ Southern Oscillation (ENSO) components ‘El Niño’ and ‘La Niña’ on populations of southern elephant seals, Mirounga leonina, were analysed. Changes in the cephalopod diet composition of moulting females at King George Island, Antarctic Peninsula were considered. The diet of female elephant seals sampled in 1991–1992 and 1992–1993 (El Niño years) were compared with those taken in 1995–1996 (La Niña year) at the same site and employing the same methodology. The squid Psychroteuthis glacialis constituted the main cephalopod prey of the seals. A reduction in the ‘Index of Biomass Ingested’ by female elephant seals (IBIF) of this prey species was observed in ‘El Niño’ years (1992, 1993) compared with the ‘La Niña’ year (1996). This reduction in biomass applied to all squid species in the seals' prey with the exception of Galiteuthis glacialis, which occurred in low numbers, but was more abundant during El Niño years than in the La Niña year.

The tolerance of the European sea bass to high salinities was determined through abrupt and gradual transfers to different hyperosmotic media. Mortality rate reached roughly 50% in fish abruptly transferred to 70 psu salinity and in fish gradually adapted to 90 psu salinity. All fish abruptly transferred to 90 psu salinity expired in less than three hours. A crisis and regulation type osmoregulatory pattern, related to the range of the osmotic shock, was recorded following abrupt transfers to the tolerable experimental media. The lethal level of blood osmolality in sea bass was determined.

The abundance of Calanus finmarchicus is known to have fallen between the present and the late 1950s in north-eastern Atlantic shelf waters. Further west in deeper water, however, long-term abundance of the copepod has risen.

An animal-borne video camera and data-logger was used to collect behavioural data on green (Chelonia mydas) and loggerhead (Caretta caretta) turtles in Western Australia. This technique provided novel insights into the behaviour of green turtles including an apparent self-cleaning behaviour. Also, ctenophores and jellyfish might be more important in the diet of these turtles than previously thought.

Most krill species undergo diel vertical migration (DVM) which is to some extent influenced by light intensity. During a solar eclipse (11 August 1999) the upward and downward movement of krill, Meganyctiphanes norvegica, inhabiting a Swedish fjord followed closely changes in light intensity. Here the eclipse was partial (77%) and the weather overcast and yet krill at 70–90 m depth were able to detect, and respond to very small changes in light. This observation of an event during mid-day which is not pre-programmed confirms light as an important triggering mechanism for krill DVM.

Two specimens of the Chinese mitten crab Eriocheir sinensis (Crustacea: Decapoda: Brachyura) were caught in the River Tyne, north-east England during 2001. The specimens were brought back to the laboratory, sexed, measured and stored in 95% ethanol. Unconfirmed reports of this species' occurrence in the River Tyne were first circulated in 1997.

The specimens of Melibe fimbriata were found during October 2001 in Stari Grad Bay (Island of Hvar, Croatia) in Cymodocea nodosa and Posidonia oceanica beds on sandy and sandy–muddy bottoms at depths of 2 to 15 m. Presently, this is the northernmost record of this lessepsian immigrant in the Mediterranean basin.

Egg masses of Loligo forbesi were encountered for the first time from a depth of 730 m at Gökova Bay (southern Aegean Sea), extending the known spawning depth in the Mediterranean Sea.

Surface occurrence of ocean sunfish (Mola mola) was recorded during summer (May–September) in the western English Channel off Plymouth over a six-year period between 1995 and 2001. Fifteen individuals of between 0.5–0.7 m estimated total length were sighted during 1651 hours of observation. Nearly all sightings (93%) occurred in June and July in water between 13 and 17°C. Sunfish were mostly associated with frontal and stratified water masses (86%) rather than in cooler, mixed water.