Juvenile anemonefish Amphiprion ocellaris were tested in two behavioural laboratory set-ups for their ability to visually or chemically recognize conspecifics. Individuals of two other species of anemonefish, A. clarkii and Dascyllus aruanus, were also used as test specimens for recognition. The results indicate that juvenile A. ocellaris recognize conspecifics visually rather than by olfaction. This is contrary to their finding mechanism of their host anemone. However, the results also indicate that the juvenile A. ocellaris are neither attracted nor deterred by the presence of conspecifics. This is contrary to the settling mechanisms of the damselfish D. aruanus and D. reticulatus, and of the temperate herring Clupea harengus. Hence the results emphasize the variation of sensory abilities and behaviours in fish larvae and juveniles. It is not an area prone for generalizations.

Minke whale (Balaenoptera acutorostrata) distribution was derived from a 12 year observation programme in the Mingan Islands (Canada) and related to three geological features of the sea-floor: maximum depth, topography and geomorphology. Minke whale distribution was not uniform nor random in relation to maximum depth and topography, however, no evident trend was found. The most prominent factor was the presence of underwater sand dunes, where significantly more minke whales were observed than on any other bottom types. Because sand dunes are the favoured habitat of the minke whale major prey in the study area, an indirect link between minke whale distribution, geomorphology and substrate type is suggested.

Morphological development of larval Prolatilus jugularis from Bahia Independencia, Pisco, Peru is described. Two hundred and thirty-two specimens were collected with plankton nets in 2000; a developmental series of 40 individuals (2.5–25.9 mm: recently hatched through transformation) was assembled using morphological features and pigmentation. Prolatilus jugularis hatches at approximately 2.5 mm, notochord flexion begins at ∼5.7 mm and ends at ∼6.9 mm, and transformation begins at an unknown size between 14.2–20.3 mm (probably near 20 mm). Diagnostic features of the larvae include a robust body with large head bearing small preopercular spines that begin to form by late preflexion stage; preanal length just under half of body length early in the preflexion stage increasing to near two-thirds of body length in the postflexion stage; and pigmentation primarily on the snout, opercular region, dorsally on the head and gut, laterally above the hindgut, and on the ventral margin of the tail through early flexion stage. A broad mid-lateral stripe begins to form on the trunk and tail late in the flexion stage and dorsal pigmentation forms on the trunk and tail in the postflexion stage. Pectoral-fin rays are first to begin forming, in mid-preflexion stage, followed by principal caudal-fin rays, then by pelvic-, dorsal- and anal-fin rays which apparently begin to form simultaneously near the end of preflexion stage. The dorsal fin is long and continuous, with III–IV short spines and 27–29 soft rays, the anal fin contains 21–23 rays, the first one or two of which may be spine-like, the pelvic fins, with I spine, 5 rays, are below or slightly in front of the pectorals (18–20 rays), and there are 9+8 principal caudal-fin rays and 36–37 myomeres.

Samples of the widely distributed sand goby Pomatoschistus minutus have been investigated genetically from ten localities in the north-eastern Atlantic, North Sea, western Mediterranean and Adriatic Sea. Levels of genetic diversity and differentiation were assessed with starch (SGE) and cellulose acetate (CAGE) gel electrophoresis for 13 enzyme systems. Genetic differentiation between spatial samples points to a reduction or even absence of gene flow between the Adriatic and the other samples, including the western Mediterranean Sea (pair-wise FST=0.37 and 0.32 for SGE and CAGE respectively). The sample from the Adriatic Sea was clearly differentiated from the other samples at the lactate dehydrogenase loci LDH-A* (SGE and CAGE) and LDH-C* (CAGE). Values for genetic differentiation between Venetian and other sand gobies were of the same order of magnitude as between P. minutus and its closest relative P. lozanoi, suggesting allopatric speciation in the lagoon of Venice. At locations outside the Adriatic Sea, the sand goby has the typical features of a marine fish with a high level of gene flow and a low degree of genetic differentiation.

The full developmental sequence from egg to juvenile of Gobius paganellus under controlled conditions is described. Embryonic development lasted 9–10 days at 18.5–20.0°C and 10–11 days at 15.0–16.5°C. Newly hatched larvae measured 3.90 mm, had the mouth and anus opened, pigmented eyes and almost no yolk. They first settled 25 days after hatching (10.0–10.5 mm total length [TL]) and showed juvenile behaviour and body form 36 days after hatching (14.0 mm TL). However, they only showed full juvenile pigmentation patterns 15 days later (17.0 mm TL) (16.0–16.5°C). In addition, a preliminary differentiation between the newly hatched larvae of the most common Gobius species of south-western European shores is presented.

Specimens and nests of Pomatoschistus pictus adriaticus have been caught for the first time along the French Mediterranean shore (Gulf of Lions). Six types of nests are found on sandy-gravelly bottom at 10 m depth and 25.3 to 27.5 g 1−1 salinity, using in 84.7% of cases, a valve of Cardium edule (3.3≤weight g≤40.6; 507≤surface mm2≤2490). Nest size, egg patch, surface area and nesting fecundity are positively correlated. Nesting fecundity varies between 669 and 4690 eggs. For a similar egg diameter, the egg height is less than that of P. minutus which spawns on the same bottom and localities. Larval length at hatching varies from 1.70 to 2.67 mm.

Young-of-the-year bass (Dicentrarchus labrax) were sampled from ten Bristol Channel sites during 1996, 1997 and 1998 to investigate whether the pattern of recruitment to south Wales nurseries observed following the ‘Sea Empress’ oil spill in spring 1996 was anomalous. Back-calculated egg fertilization (spawned) dates indicated that early spawning events (February–March) at the Trevose Head spawning area provide recruits to south Bristol Channel nurseries, and that the majority of recruits to south Wales nurseries arise from subsequent spawning events. Recruitment of post-larvae to all nurseries in the Bristol Channel starts in late June–early July. The late recruitment of 0-group bass to all nurseries in 1996 was attributed to lower water temperatures in February and March than in 1997 and 1998, and was not restricted to south Wales. However, 0-group bass were relatively less abundant in 1996 at sites nearest the ‘Sea Empress’ oil spill, suggesting a possible effect of the latter on survival of post-larvae in the nurseries, rather than during the offshore egg and larval stage.

Spatial distribution patterns of black anglerfish, Lophius budegassa were examined in relation to size category, bathymetry, locational covariates, and season. Data were collected during a 2-y period (1998–1999) of quasi-synoptic seasonal sampling using demersal trawl surveys in the Aegean Sea. Generalized additive models (GAMs) were used to test the hypotheses that there was size-related variation in species' habitat associations and that the study area might serve as a nursery ground for black anglerfish. The current results supported these hypotheses. Data are presented that reveal size-dependent aggregation patterns of black anglerfish and an important habitat utilization of the north-eastern Aegean area. The modelled anglerfish abundances showed a strongly non-linear dependence on the explanatory covariates. The different size-classes exhibited significant seasonal effects and preferences for specific regions and distinct water depths. The present results also suggested that 1-y-old fish and potential spawners appeared to concentrate in the vicinity of the same areas. Two main areas of juvenile aggregations were detected in the deeper water regions of the study area on a seabed of around 300 m depth; both emerged in the proximity of the locations of larger fish. The bathymetric distribution of intermediate size anglerfish followed an inverse trend, with fish captured mainly in shallower waters. Results indicated a preferential aggregation of 1-y-old L. budegassa in the study area that is hypothesized to influence the supply of recruits to distant regions of the Aegean Sea.

The embryonic and larval development of the pipefish Nerophis lumbriciformis is described. The full development sequence lasted 30 d (at 14–15°C), being shortened to 25–26 d at higher temperatures (16–17°C), and hatching occurred throughout a 2–3 d period. Unlike species of the genus Syngnathus, the newly hatched larvae presented a functional mouth apparatus and the yolk sac completely absorbed.

A comparison of body size and flipper size was carried out on green turtle (Chelonia mydas) hatchlings produced from natural nests at two beaches on Ascension Island, South Atlantic and one beach in northern Cyprus in the Mediterranean (N=18 nests; N=180 hatchlings). Hatchlings from Ascension Island were significantly larger and heavier than hatchlings in Cyprus, a likely consequence of maternal size effects. Incubation temperature appeared to influence body size of hatchlings on Ascension Island with higher temperatures producing smaller hatchlings. Both hind and fore-flipper area scaled positively with body size. In proportion to body size, hind-flipper area appears relatively consistent among the Atlantic populations but is smaller than hatchlings measured in Hawaii.

A line transect survey was conducted in July/August 1998 to investigate the distribution and abundance of cetaceans off north-west Scotland. Over 2156.5 km of survey effort, 304 sightings were recorded of which 184 were identified to species. Nine species were identified: Atlantic white-sided dolphin Lagenorhynchus acutus, fin whale Balaenoptera physalus, sei whale Balaenoptera borealis, long-finned pilot whale Globicephala melas, sperm whale Physeter macrocephalus, common dolphin Delphinus delphis, harbour porpoise Phocoena phocoena, white beaked dolphin Lagenorhynchus albirostris and Risso's dolphin Grampus griseus. The Atlantic white-sided dolphin was the most relatively abundant species. The relative abundance of large whales and dolphins was greatest in the Faroe–Shetland Channel. The continental slopes of this area are undergoing development by oil industries and concerns have been raised about the potential impacts of these activities on cetaceans. These waters are used year-round by cetaceans and provide feeding and breeding grounds and are a migration route for large whales.