Mitochondrial dehydrogenases, antioxidant enzymes, transaminases and cytochrome P450 activity have been studied from the digestive gland of Mytilus galloprovincialis, reared in a non-polluted area of the Mar Grande of Taranto (Ionian Sea, Mediterranean).

A female Octopus macropus, the first ever observed spawning, attached eggs (4·0×1·2 mm, with a chorion stalk 4 mm in length) individually or in clusters to a hard substrate, and brooded them till hatching. Hatchlings measured 4·0 mm in dorsal mantle length, 5·5 mm in total length and were planktonic; their short arms had seven suckers each, the outer demi-branch of each gill had ten lamellae. The chromatophore pattern confirmed an earlier identification of young individuals from the plankton (Naef, 1923).

Phenoloxidase (PO) has been shown to be present in both invertebrates and vertebrates, yet little is known about the PO in Branchiostoma belcheri tsingtauense. The present study demonstrated that the PO activity existed histochemically the epithelial cells of the gill bar and intestine of adult animal, producing brown to black melanin deposits. Ultrastructural examination revealed that PO reaction products were localized in the cytoplasmic granules of the epidermal cells, the epithelial cells of gill bar and intestine and most of them were electron-dense and homogenous. Frequently, the PO reaction products were also observed in the secondary lysosomes.  The mucus from the body surface had little antibacterial activity against Escherichia coli, but it enhanced the antibacterial activity of L-dopa and the enhancement was suppressed by PTU, a PO specific inhibitor. This indicates that the active material inhibiting the E. coli growth in the mucus is PO.

The third record of the sharpnose seven-gill shark Heptranchias perlo (Selachii: Hexanchidae) north of the Bay of Biscay is reported. The 101 cm total length specimen, which was taken incidentally on a commercial bottom-set longline at a depth of 166 m, was an immature female. Beaks belonging to the short-finned squid Illex coindetii (Cephalopoda: Ommastrephidae) were recovered from the stomach, and an unidentified species of nematode was found parasitizing the stomach mucosa.

Ontogenic change patterns in otolith Sr:Ca ratios were examined in the Russian sturgeon, Acipenser guldenstadti in the Caspian Sea. Otolith Sr:Ca ratios fluctuated widely during the life history in accordance with the migration pattern from freshwater to brackish water habitats, i.e. all specimens exhibited a typical anadromous pattern in the ratio. Several specimens had two transition points in otolith Sr:Ca ratios from the low ratios to the high indicating that those specimens had a flexible migration strategy in the ambient water and had the possibility of migrating downstream to the Caspian Sea multiple times after spawning in a freshwater habitat.

The beryciform fish Hoplostethus mediterraneus (Beryciformes: Trachichthyidae) 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 and 618 m, more than 80% being taken at depths of between 234 and 422 m. Immature fish ranged from 4 to 13 cm in length and were present at all seasons. Of the mature individuals, males ranged from 7 to 17 cm and females from 7 to 21 cm. From autumn until spring, fish with gonads at various stages of maturation were present, although there were no specimens with mature gonads.

Time series of ichthyoplankton surveys targeted at herring larvae describe the distribution of spawning in the north Irish Sea by mapping the occurrence of very young larvae. The surveys suggest, that like other herring stocks, the spawning grounds of Irish Sea herring vary over the years. Currently, spawning at the Mourne location is greatly reduced whereas spawning has occurred at a newly described site to the north of the Isle of Man (off the Point of Ayre). Whilst spawning is dominated by autumn spawners in late September, some spawning occurs through to January.

Ectoparasitic crustaceans (Copepoda: Caligidae) occurred at considerable frequency in stomach contents of young specimens of Diplodus sargus and Diplodus puntazzo (Pisces: Sparidae) from two central Mediterranean coastal lagoons. This finding suggests that the ectoparasites might give a non-negligible contribution to the diet of the studied fish species and reveal a certain adaptive advantage of cleaning behaviour in coastal environments.

The Mediterranean parrotfish Sparisoma cretense is reported for the first time along the south-eastern coasts of Apulia (Ionian Sea, south-east Italy). Only juvenile specimens of S. cretense were observed during visual census surveys carried out in late August 2000, whereas adults were never observed in, or reported from, this region. Juvenile parrotfish were 3–4-cm long (TL), with a light-grey livery, pale-yellow heads and marked yellow margins around the eyes. They were recorded at 5–15 m depth, whereas they were absent near the surface (0–2 m depth) and in deeper areas (25–28 m depth). The possibility that climatic changes occurring in the Mediterranean basin (i.e. water warming) would be involved in the spreading of S. cretense outside its typical distribution range is discussed.

This study provides a description of the Mediterranean monk seal (Monachus monachus) diet from the Aegean Sea coast of Turkey. A total of 23 prey items belonging to five species were identified from the two stomachs examined. Cephalopods constitute the dominant prey group by weight (94·01%). Sarcotragus sp. (Porifera) and Posidonia oceanica (Magnoliophyta) are assumed to be incidental prey. Of the cephalopods identified, Eledone moschata and Bathypolypus sponsalis were encountered for the first time in a monk seal stomach.