Serological methods for prey identification have been applied to detection of residues of sandeel (Ammodytidae) protein in faeces of common seals (Phoca vitulina) and grey seals (Halichoerus grypus) from the Moray Firth, north-east Scotland. Antisera raised to muscle protein from Ammodytes marinus were evaluated by testing their reactions with protein extracts made from a range of North Sea fish species and protein residues in in vitro digestates, seal digestive tracts and seal faeces. It was concluded that, using fused rocket immuno-electrophoresis, linkage of precipitin peaks from unknown samples with peaks from standard sandeel extract was a reliable indicator of the presence of sandeel in the unknown sample. Seasonal variation in the incidence of sandeels in common seal diet in the Moray Firth was examined by identifying otoliths, bones, and proteins, and all three methods indicated that sandeels occurred in the majority of samples tested in the summer, but were less important during the winter. Proteins were detected in fewer samples than otoliths, particularly in February and March. Possible reasons for this difference are discussed. Serological identification of sandeel proteins is potentially applicable to dietary studies on all marine predators.

The effect of two 70 W underwater electric lamps on the catch rate of a commercial bottom otter trawl was determined by comparative trials both at night and in daylight. It was found that, although the overall numbers and weights of fish caught did not differ, most of the species which were caught in large enough numbers for a judgement to be made showed a reaction to light. Three species, Trachurus trachurus, Merlangius merlangus and Trisopterus minutus were attracted and four species, Eutriglagurnardus, Micromesistius poutassou, Merluccius merluccius and Limanda limanda were scared off by light.

The possible use of lights to further the development of selective commercial bottom trawling by attracting or scaring particular species is discussed.

Studies on the settlement and the subsequent recruitment of intertidal organisms are crucial steps in understanding their population structure in a particular bioregion. However, studying the recruitment of intertidal organisms such as barnacles, with two-phase life cycle, and understanding the determinants of recruitment is a complex problem. Many processes which operate during the pelagic pre-settlement phase and benthic post-settlement phase at different spatial and temporal scales can determine the fate of barnacle populations. In this study, observations were carried out on settlement and recruitment of the intertidal barnacle Balanus amphitrite from a tropical environment influenced by monsoons at spatial and temporal scales. Settlement and recruitment both showed significant temporal variations. In general, settlement and recruitment was lower during the monsoon season except during monsoon breaks. Consistency in settlement and recruitment was mostly observed during the pre-monsoon season, and it coincided with peaks in larval abundance observed during the same season. In general, settlement remained more or less similar on different types of substrata, whereas recruitment differed significantly. Temporal variations observed in settlement and recruitment of barnacles could be due to the influence of monsoons in this region, which leads to seasonal fluctuations in physical factors such as local hydrodynamics, that influence the retention and dispersal of larvae in the adult habitats, and could also be due to variations in the availability of food for the larvae and the settled populations.

The faunas of volcanic islands must necessarily be introduced, and more recent introductions can be recognized by the patterns of their distributions. This is obvious in the Canary Islands, where we have spent 30 days studying distributions of Spirorbidae. We now regard these as a distinct family following Pillai (1970). We sampled all the major islands, by shore collecting and diving to about 10 m, and on almost all we found nine Mediterranean species, namely Protolaeospira striata (Quiévreux, 1963) and the eight opercular incubators (species of Pileolaria and Janua) that have been recorded from both Marseilles (Zibrowius, 1968) and Chios (Bailey, 1969).

In the family Alepocephalidae there are ca. 19 valid genera (Markle, personal communication). Whilst luminescence has never been observed, there are four genera, Xenodermichthys, Photostylus, Rouleina and Microphotolepis, which contain species bearing structures that have been interpreted anatomically as photophores (Herring & Morin, 1978). Among these four there is a remarkable diversity of photophore structure. The photophores of Xenodermichthys and Photostylus are similar in having well developed central cores (reddish violet in Xenodermichthys) and reflector layers, yet those of Xenodermichthys are sessile whilst those of Photostylus are borne on stalks (e.g. von Lendenfeld, 1887; Best & Bone, 1976). Not all species of Rouleina have light organs but where they are present they are sessile. Photophore structure of Rouleina has been examined only in R. maderensis Maul and was found there to be rather degenerate in adults (Markle, 1978). The light organs of Microphotolepis multipunctata Sazanov and Parin differ yet again in being scale covered, which contrasts with the naked photophores in the other three genera (Sazanov & Parin, 1977). The abundance and distribution of photophores in adults also varies with genus and species. Thus in Microphotolepis and Xenodermichthys they are extremely numerous and regularly arranged but in Photostylus they are few and less ordered (Günther, 1887; Beebe, 1933; Sazanov & Parin, 1977). In different species of Rouleina photophores may be relatively abundant and regularly arranged or few in number without such regular pattern (Maul, 1948; Uyeno & Kishida, 1977; Markle, 1978).

The digestive system of sea spiders (Pycnogonida) presents peculiarities that have not been discussed in the context of their ecology or feeding behaviour. We investigated the digestive system of two Mediterranean species, a carnivorous species Ammothella longipes and a detritivorous Endeis spinosa, with special focus on its correlation with behavioural feeding habits. The midgut and hindgut sections did not present significant differences between the two species, but major differences were observed in the foregut, reflecting concordance to their diet and their feeding behaviour. Jaws, setose lips, the structure of the pharyngeal filter and musculature of the proboscis are the main differential elements when comparing feeding habits of A. longipes and E. spinosa. These elements are responsible for the reduction of the food pulp down to subcellular size. The digestion process observed in the species studied agrees with that observed in other pycnogonid lineages, but differs from most marine arthropods mainly because of the absence of midgut gland cells and the presence of a unique multifunctional type of midgut epithelial cell. Epithelial digestive cells are present in a small ‘resting’ form during starvation periods. During digestion, secretion granules possibly containing zymogen move to their apical border to be secreted to the midgut lumen, secondary lysosomes are formed and intracellular digestion occurs within them. Residual bodies are formed within the epithelial cell and released to the midgut lumen to be transported towards the hindgut. The characteristics of the digestive process of the pycnogonids studied seem to reflect a plesiomorphic state in arthropods.

This study was conducted in February, April and June 2009 at three stations in the southern Adriatic. Occurrence of the dinoflagellate Noctiluca scintillans and tunicates Salpa fusiformis and Salpa maxima in high abundances for the oligotrophic open sea, indicates the importance of physical forcing (vertical mixing) and inflow of nutrient-enriched Atlantic water, due to the Bimodal Oscillating System (BiOS) mechanism, into the Adriatic Sea thus creating an environment favourable for their rapid increase. This is the first time a bloom of N. scintillans has been recorded in the open southern Adriatic (OSA). High abundance of Noctiluca and salp populations in the OSA was characterized by low abundance of phytoplankton and other zooplankton, with obvious trophic implications (reduction of food availability to crustacean primary consumers). Moreover, during the S. maxima bloom in June 2009, calanoid copepods and appendicularians were almost completely absent (<1 ind. m−3).

A single maturity classification key applied to five common chaetognath species of the eastern Mediterranean is presented. The efficiency of the key was tested using biometrical data: body length (BL), ovary length (OL) and seminal vesicle width (SVW). For each species the key proved easy to use and efficient in the distinction of the maturity stages providing a satisfactory size separation between them.

Density and spatial distributions on an intermediate scale of two flatfishes—marbled flounder Pleuronectes yokohamae, and the brown sole Pleuronectes herzensteini (Pisces: Pleuronectiformes) within large (10,000–100,000 m2 patches of homogenous substratum (sand and silted sand)) were studied. Both species dominated in the demersal fish community. Densities of brown sole, were significantly higher in both types of habitat. Flatfish distribution was highly patchy and the mean fish densities in groups were as much as ten times higher than the mean fish densities in the area. More than 85% of all recorded flatfish were found within groups. Mixed groups with both species were most prevalent. The number of flatfish in one group ranged from 2 to 20. Brown sole was more abundant in the area and dominated in mixed groups. Levels of contacts between group members and densities within groups were inversely related to visibility condition. It is suggested that flatfish form a group and stay in the group, attracted by foraging movements of other flatfish and by plumes of upset particles caused by their bottom digging movements.

Boring sponges are an important component of bioeroder assemblages in tropical coral reefs. They are considered as a potential threat for coral reef health, and the increase of dead corals is expected to promote their abundance. The relationship between the availability of dead coral substrata and the development of boring sponge assemblages was evaluated during El Niño 2015–16 at five reefs from Zihuatanejo, Guerrero, Mexico. Environment and substrate quality were assessed. Overall, environment conditions remained normal in relation to previous studies in the area. Only water temperature showed unusually high records at all sites and coincided with bleaching and mortality of corals, possibly caused by the effects of the El Niño event. Abundance of boring sponges in dead corals and coral rubble was lower than during previous studies. Although sponge abundance was not directly related to cover of both dead corals and coral rubble, cover of dead corals showed a high correlation with the variation in the structure of sponge assemblages across sites. Cliona vermifera dominated sponge assemblages at all sites, and its abundance was high under conditions of high cover of live corals and low cover of bleached corals. Since overall sponge abundance responded in a similar way, these results suggest that boring sponge assemblages dominated by C. vermifera are enhanced by conditions favourable for corals. Our results imply that El Niño events in the Mexican Pacific are not likely to cause immediate population outbreaks of boring sponges.

Allozyme electrophoresis was used to estimate the genetic divergence between three species of South African Helcion and the north-east Atlantic H. pellucidum (Patellidae). At a finer level the genetic relationships among South African Helcion were explored. Twenty-one loci were resolved for all the species. High values of expected heterozygosities (0·202–0·341) were found for the genus. Phenetic analysis (UPGMA (unweighted pair-group method with artihmetic averaging) and Distance Wagner Procedure) and cladistic parsimony methods (alleles as binary characters and loci as multistate unordered characters) agreed in showing the same topology for the tree which represents the genetic relationships among Helcion species. The north-east Atlantic H. pellucidum was the most divergent species showing high values of Nei's genetic distances (1·423–1·654) with its South African congeners. In the literature such values of genetic divergence have been associated with non-congeneric species. The degree of genetic divergence (0·351–0·615) found within the South African branch was characteristic for congeneric species. The results of this study supported the monophyletic condition of this branch, and showed H. pectunculus and H. pruinosus to be more closely related to each other than to H. dunkeri. Nevertheless, the monophyly of the genus Helcion is uncertain and therefore its taxonomic status was questioned. A possible independent origin for northern and southern hemisphere species of Helcion is considered.

Two species of large extension feeding barnacles are abundant on exposed tropical rocky shores of northern Australia. The cirri of many specimens carry varying numbers of a commensal diatom in some cases with as many as 2000 individuals on a single cirrus. The araphid diatom resembles the genus, Lichmophora within the family Fragilariaceae although no description has yet been published. Species of Lichmophora are common benthic diatoms in these waters as an epiphyte on macroalgae and common primary fouling diatoms on test panels. The diatom reported here has not been found on any substratum other than the barnacles Tetraclita squamosa and Australobalanus imperator, very rarely on Balanus amphitrite. Analysis of the diatom distribution on the cirri shows significantly higher numbers on the posterior captorial cirri. The effect of commensal diatoms on the feeding efficiency of the barnacles is discussed.

Five of 26 flathead mullet (Mugil cephalus) captured in the Seekoei River estuary in South Africa showed haemogregarine infections. Both trophozoites and gamonts were observed, and image analysis technology was used in parasite morphometric description. Gamonts were compared with those of Desseria mugili from Brazil and found to be different. The parasite mostly closely matched a haemogregarine previously illustrated, but not described from South Africa, and apparent lack of merogony suggested that it was a species of Desseria.

The paper describes the design and use of a tide machine capable of producing near-sinusoidal hydrostatic pressure cycles varying in period from 12 to 999 min and in amplitude from 0·4 to 3·2 m. In conjunction with infra-red detection units and a microprocessor logging system the apparatus can be used to detect and record the response of a variety of organisms to cyclic pressure changes.

The numbers of young fish, excluding clupeids, taken in a 2 m ring trawl in the plankton off Plymouth were as high in the year 1966 as they were during the 1920s and early 1930s. There is thus evidence that the period of decreased abundance which began after 1934 and has apparently persisted since then may have ended. The year 1966 was a very early year for spring spawners and this can be correlated with the high water temperatures prevailing in the early months of that year.

Distribution of fur seals Arctocephalus australis has been studied in October 2007 on the western, southern and eastern Falkland shelves during the survey of spawning grounds of the red cod, Salilota australis. Fur seals presence/absence, numbers and sex were recorded at every oceanographic station. Animals were found foraging on the shelf edge south-west of the islands, in a productive zone with quasi-stationary eddies at a periphery of upwelling. It was also the zone of maximum abundance of lobster-krill, Munida spp.—an important food source of fur seals and aggregations of both red cod and blue whiting, Micromesistius australis. No fur seals were found in waters of the relative cold and saline Falkland Current as well as in the relatively warm, fresh and oxygen-rich waters of Argentine Drift. It allows supposing that position and extension of the foraging grounds are caused by oceanographic features determining distribution of prey species.

Suspected viral erythrocytic necrosis (VEN) was detected in two specimens of the intertidal fish Mauligobius maderensis (Teleostei: Gobiidae) from Madeira, Portugal. While one host was lightly infected, the other showed intraerythrocytic cytoplasmic inclusions within all mature erythrocytes examined. The inclusions were round to oval, 0·8–2·0 μm in diameter, and most were associated with dense eosinophilic granular areas of various sizes and shapes. Up to three of these granular regions accompanied each inclusion body, but they were sometimes widely separated from it. In a number of infected erythrocytes, a granular halo was observed surrounding the nucleus. The cytoplasm enclosed by the halo often had a different refringence from that outside. None of the 120 other fishes examined from Madeira, representing 43 species of intertidal, pelagic, and deep-sea origin, had detectable infections.

In order to determine optimal feeding regimes for captive corals, prey capture by the scleractinian coral Galaxea fascicularis was determined by measuring clearance of prey items from the surrounding water. Colonies of G. fascicularis (sized between 200 and 400 polyps) were incubated in 1300 ml incubation chambers. Nauplii of the brine shrimp Artemia sp. were used as the prey item. A series of incubation experiments was conducted to determine the maximal capture per feeding event and per day. To determine maximal capture per feeding event, total uptake of nauplii after one hour was determined for different prey item availabilities ranging from 50 to 4000 nauplii per polyp. To determine maximal capture per day, the corals were subjected to four repetitive feeding events at three different prey item densities (50, 100 and 150 nauplii per polyp). Alongside these quantitative experiments, it was tested to what extent the feeding response of corals is triggered by chemical cues. One hour after food addition, extract of Artemia nauplii was added to the incubation chambers to test its effect on subsequent prey capture rates. In all experiments, prey capture was expressed as the number of nauplii consumed per coral polyp. Total capture of Artemia nauplii by G. fascicularis after a single feeding event increased linearly up till a prey item availability of 2000 nauplii per polyp. Maximal capture per feeding event was estimated at 1200 nauplii per polyp, which is higher than rates reported in previous studies. It became apparent that at high densities of Artemia nauplii, the clearance rate method does not discriminate between active capture and passive sedimentation. Repetitive feeding with 50 nauplii per polyp resulted in a constant total prey capture per feeding event. At a supply of 100 nauplii per polyp, total capture decreased after the first feeding event, and remained constant during the subsequent feeding events at a level comparable to the lower food availability. However, at a supply of 150 nauplii per polyp, total capture per event was higher throughout the entire four-hour incubation period, which obfuscates an accurate estimation of the maximal daily food uptake. In all incubations, a decrease in capture efficiency was observed within the course of the feeding event. In all repetitive feeding experiments, capture efficiency increased immediately upon addition of a new batch of food. This increase in efficiency was not caused by a priming effect of extract of Artemia. The inconsistencies in the data show that estimates of prey capture based on clearance rates should be interpreted with caution, because this method does not take into account potential dynamics of prey capture and release.

During the two years which I spent at Plymouth I collected a number of notes on the occurrence and distribution of the Hydroidea of the district, with the intention of giving a full account of the representatives of the group in the Plymouth area. My unexpected departure has prevented my carrying out this intention, but it has seemed to me worth while to publish my notes, fragmentary as they are, in the hope that they may be useful to my successors, and particularly because the list of the Hydroidea given in Part ii of the first series of this Journal is very imperfect. The list of species now given is incomplete, and had I had the time to search more closely for the inconspicuous and deep-water forms I should have been able to add largely to it. One species, which I only succeeded in obtaining twice, appears to be new to science.