In Ireland the purple sea urchin Paracentrotus lividus (Echinoidea) typically inhabits intertidal bored holes. At Lough Hyne, Co. Cork, a population occurs associated with rock scree in the shallow subtidal zone. This study provides unequivocal quantitative evidence to demonstrate diurnal migration in a population of P. lividus at Lough Hyne, Ireland. Most size groups/age-classes did not to migrate, the youngest always and oldest never occurring under rocks. Those that did migrate between the lower and upper surface of rocks (2+, 3+ and 4+ age categories) did so in exactly the reverse circadian pattern to those described from the Mediterranean Sea.

Luminescence in Amphipholis squamata has only been observed from chemically stimulated individuals, and the present laboratory study assessed the natural expression of luminescence following interaction with co-occurring organisms. The luminescence occurred only in response to (mechanical) stimulus and ranged from weak to intense reaction depending on the contact organism. Only crustaceans triggered an intense luminescence. Brachial autotomy also occurred after prolonged interaction and the luminescence continued only from the autotomized arm, which could lure the crustacean. The study showed that A. squamata luminescence could be naturally stimulated by co-occurring organisms, and the light produced sufficiently intense to be detected.

The diet of common wolffish Anarhichas lupus from the North Sea is described, from a total of 143 wolffish stomachs, of which 112 contained food. The main prey were crustaceans and molluscs, together representing almost 70% of diet by relative frequency of occurrence in stomachs. Wolffish >55 cm preferred polychaetes and gastropods while wolffish <55 cm preferred sea urchins and brittle stars. The occurrence of empty stomachs was significantly less in spring than in summer or in autumn/winter. Meal size was lowest in winter and highest in spring. These data reflect a period of low food intake in winter during spawning and tooth replacement, followed by a recovery feeding episode in spring.

Aberrant statolith microstructure was observed in an immature female of the squid Todarodes sagittatus (Cephalopoda: Ommastrephidae) caught in the Moroccan shelf. The paralarval statolith, (a central part of adult statolith that developed at paralarval stage), showed the first 12 growth increments outside the nucleus was reversed to the posterior side of the adult statolith, and its main axis was turned perpendicularly to the main axis of the adult statolith. However, further statolith growth followed the common pattern, and the statolith acquired its normal shape at the level of 55–60 growth increments. Such aberrance in a direction of the paralarval statolith can be explained by its complete detachment from the macula statica princeps (MSP) during strong impact to the head of the paralarva (e.g. by a predator) and further occasional re-attachment of the statolith to the MSP again.

The systematic position of the giant squid Architeuthis remains unresolved but comparison of beak morphometrics is an approach that has not been attempted before. Additional data for the relationship between mantle length (ML) and lower beak rostral length (LRL) suggest that Architeuthis sp. in the North Atlantic, South Africa and New Zealand are parts of the same asymptotic relationship. Comparison of beak dimensions of Architeuthis from the North Atlantic, South Africa and New Zealand with those of two distinct species of Todarodes, from the Mediterranean and southern Africa, indicate that there may be only one species of Architeuthis in these three regions. No consistent morphological evidence has yet been found to indicate more than one species of Architeuthis in the Atlantic or in the southern hemisphere.

The intertidal insect Anurida maritima (Apterygota: Collembola) has a circatidal rhythm of locomotory activity on the soil surface which was observed during both the day and the night. The main function of this activity was foraging for food. When a superabundant food supply was provided on the upper shore, this completely repressed the usual migration to the lower shore. There was a clear rhythm in feeding activity which was highest shortly after the sea uncovered the insects' shelters and declined rapidly during the intertidal period. The circatidal rhythm of locomotory activity persisted in the laboratory in constant light for seven days (15 cycles). A free-running rhythm underlying the degree of aggregation was also detected.