Experimental studies of plankton luminosity have been made with specially designed photomultiplier equipment; this records (on a Servograph Recorder) the flashes given off either by a sample of plankton or by individual animals placed in a container in a dark observation chamber. The apparatus is described.

Apart from preliminary laboratory records on the flashing of Beroë, Pleurobrachia and Pyrosoma, and record of the general luminosity in the sea at a depth of 62 m (made with an underwater version of the apparatus), the main work has been a laboratory study of the luminescence of dinoflagellates and of the euphausiacean Meganyctiphanes norvegica.

The dinoflagellate experiments showed the inhibiting effect of light, both natural and artificial, on luminescence, and the stimulating effect of mechanical disturbance which may override the former inhibition. A rise in temperature increased luminosity and cooling reduced it. A difference in the pattern of the luminosity of plankton samples containing dinoflagellates was shown by the introduction of actively swimming animals of different kinds. The dinoflagellates in the samples were mainly Peridinium depressum, Ceratium horridum and C. tripos var. balticum.

The Meganyctiphanes experiments showed a spontaneous flashing in seventeen out of twenty-seven tests and in one test the animals maintained such activity for the greater part of a 24 h period. In addition to their bright flashing, the photophores would at times keep up a dull glow for long periods (especially see the observations of F. Körte in the Appendix). Spontaneous flashing does not only occur in the breeding season as had been suggested by Mauchline (1960).

Limacina retroversa (Flem.) has been known in the Channel for over twenty-seven years and was several times recorded by Gough (1907) and Bygrave (1911) in the plankton reports (see Marine Biological Association, Plymouth Marine Fauna, 1931, p. 265), both from inshore and from outside. In recent years the more frequent collecting in the waters round Plymouth has shown that it may be present throughout the year, although much the most abundant in summer. Not only is it found in the outside waters but it is also often present in the Sound and even at the mouths of the estuaries.

Freshly captured Nautilus macromphalus were observed to place new cameral liquid into emptied or partially emptied chambers, both at the surface and at 250 m, in response to sudden buoyancy increase. The sudden addition of buoyancy was accomplished either through removal of cameral liquid from chambers, removal of shell material from the apertural region of the body chamber, or by cementing buoyant corks on the sides of the shell. A maximal refilling rate of 100 μl/h was observed. The osmolality of refilled cameral liquid was observed to match closely the osmolality of the original cameral liquid. The refilling mechanism allows Nautilus to regain neutral buoyancy after sudden buoyancy gain, such as could be expected to occur from shell loss due to predatory attack on the Nautilus, or from shell breakage.

A survey of the sandy beach at Port Erin, Isle of Man, was made in. September, 1931. Observations were made, at a number of stations, involving simultaneous records of the macro-fauna and its density, and certain physical and chemical factors of the sand and interstitial water, as well as tidal level on the beach. The results enable certain general conclusions to be drawn as to the causes of the observed distribution of species, and of the differences between the faunas of this and some Scottish beaches. Plans are given, indicating tidal contours, salinity, and grade composition, in situ on the beach, together with frequency diagrams for five dominant species.

Ontogenetic and seasonal diet changes of the juveniles of the marine fish Micropogonias furnieri, a species inhabiting Bahía Blanca estuary (Argentina), were investigated. Two size-related dietary shifts, at 4·00 cm and 7·00 cm total length (LT), respectively, were found. Small juveniles (1·00–3·99 cm LT) ate mostly chaetognaths (Sagitta friderici); medium-sized juveniles (4·00–6·99 cm LT) fed intensively on mysid shrimps (mainly Neomysis americana) and polychaetes, whereas large juveniles (7·00–15·99 cm LT) fed almost exclusively on epibenthic crustaceans (primarily Peisos petrunkevitchi). Increased mouth gape was related to increased size spectrum and mean size of the most important prey items consumed by M. furnieri. Juveniles <510 cm LT ate prey items almost as large as their mouth opening, whereas juveniles >410 cm LT were capable of consuming larger prey items than those found in their stomachs, indicating that the maximum size of prey eaten was not constrained by mouth gape. Seasonal and selectivity dietary analyses showed that M. furnieri can be a highly opportunistic selective feeder. Juveniles relied on S. friderici and P. petrunkevitchi throughout the year, except in summer, when mysids abundance increased in the estuary. Electivity values also showed that prey size and prey relative abundance are important factors in prey selection mechanisms.

Four distinct Franciscana Management Areas (FMAs) have been proposed based on several lines of evidence including genotype, phenotype, population response and distribution. To determine if differences in external morphology fit this division, a canonical variate analysis was carried out for males and/or females from FMAs I to IV using up to 14 characters. A total of 78 adult specimens were analysed. More than 90% of the differences between groups were summarized by three canonical variates. Females were larger than males in all areas. Females from FMA IV were of intermediate length between those from FMA I and FMA III and individuals from FMA II were smaller than those from all other areas. Position of dorsal fin and morphology of the anterior body region, differentiate individuals from FMA I and FMA III. Morphological differences found in this study give additional support for the proposed FMAs. Since habitat characteristics and franciscana feeding ecology vary regionally, it is possible that observed morphological differences are due to ecological divergence for niche occupation. The indication of a discontinuous distribution, consistency between genetic and morphological evidence, and a short time genetic divergence, might indicate that franciscanas inhabiting FMA I represent a distinct subspecies.

Blooms of the dinoflagellate, Gyrodinium aureolum have been recorded on the coasts of Europe and are fully reviewed by Tangen (1977) and Boalch (1979). The significance of these blooms is considerable, and with the increase in the eutrophication of inshore waters they are now an important factor influencing the ecology of coastal waters (Boalch, 1984). Their numbers increase to concentrations in excess of five million cells per litre during warm, stable conditions resulting in the waters becoming a greenish-brown colour, ‘slimy’ and with a characteristic smell (Boalch, 1979; Jenkinson, 1986). At these concentrations there are reports that local fauna may be adversely affected and certain species will die.

Sponge species are infamously difficult to identify for non-experts due to their high morphological plasticity and the paucity of informative morphological characters. The use of molecular techniques certainly helps with species identification, but unfortunately it requires prior reference sequences. Holotypes constitute the best reference material for species identification, however their usage in molecular systematics and taxonomy is scarce and frequently not even attempted, mostly due to their antiquity and preservation history. Here we provide case studies in which we demonstrate the importance of using holotype material to answer phylogenetic and taxonomic questions. We also demonstrate the possibility of sequencing DNA fragments out of century-old holotypes. Furthermore we propose the deposition of DNA sequences in conjunction with new species descriptions.

This paper aims to study the morphological and gonadal maturity of the swimming crab Callinectes danae in the Santa Cruz Channel, Brazil. Crabs of both sexes were measured at carapace width (CW), carapace length (CL), abdomen width (AW), length of the right chelipod (LRC), and dissected to visualize the gonads. The gonadal maturity was estimated based on the frequency of mature individuals per class of CW, and the determination of morphological maturity was based on the relationship between the structures LRC versus CW for males and AW versus CW for females. The sizes that 50% of females reached gonadal and morphological maturity were 62.5 and 59.5 mm CW respectively. In turn, the sizes that 50% of males reached gonadal and morphological maturity were 74.5 and 70.5 mm CW respectively. In the analysis of dispersion of points in relation to AW versus CW, it could be observed that juvenile females showed positive allometry and adult females showed negative allometry, indicating a higher growth rate during the juvenile phase, related to the need of expanding the abdomen for egg incubation at the adult phase. In the relation LRC versus CW, it was observed that both juvenile and adult males showed positive allometry, but changes in the degree of allometry were evident between the two phases. The exceeding growth of the chelipod of males may be related to the reproductive process, including courtship and agonistic interactions with other males.

The life cycle of the South African gnathiid isopod, Gnathia pilosus, was studied using the common east coast tidal pool fish, Scartella emarginata and Antennablennius bifilum as hosts. Laboratory studies observing the feeding ecology of these temporary ectoparasites determined that the second and third unfed larval stages (zuphea larvae 2 and 3) took an average of 3 hours 52 minutes and 4 hours 19 minutes to feed respectively. After feeding, the second stage fed larvae (praniza 2) took 35 days to moult into the third zuphea form. Male and female praniza 3 larvae could be discerned before their final moults into adults which took place approximately 42 and 48 days respectively after their blood meals. Fertilization occurred within 24 hours after the female had completed her moult. It was thus estimated that the complete life cycle from the first larval stage to adult took between 134 to 140 days in water temperatures ranging between 20°C and 25°C. The length for this life cycle is unexpectedly long for gnathiids living in subtropical waters and may indicate that water temperature is not always the main factor in determining the duration of gnathiid life cycles.

Two razor clam populations from two shores in North Wales were identified on morphological grounds as Ensis siliqua (L.) and E. ensis (L.). Ensis siliqua occurs in fine sand on the exposed south-westerly facing shore of Newborough beach, whilst E. ensis inhabits the coarser sediment of Penmon beach, a sheltered north-easterly facing shore in the Menai Strait. At Penmon smaller E. ensis (<100 mm) inhabited sediments at mean low water of spring fides, whereas larger individuals (>100 mm) occurred almost subtidally at extreme low water springs. No small E. siliqua (<110 mm) were found on Newborough beach, where there has been a noticeable decline between 1990 and 1992 in the number of individuals larger than 175 mm. Growth of the two species was different. The von Bertalanffy growth constant, k, was similar in the two species, but E. siliqua had a larger asymptotic length than E. ensis.

This paper is the second of a series dealing with the annual cycle of growth andreproduction in British ascidians; a previous paper (Millar, 1952) dealt with the speciesDiplosoma listerianum (Milne Edwards), Ciona intestinalis (Linnaeus),Ascidiella aspersa (Muller), andBotryllus schlosseri (Pallas)

The present investigation is concerned with the growth, the course of sexual reproduction and establishment of new generations, and the histological changes in the gonad throughout the year, in the ascidianDendrodoa grossularia (family Styelidae).

Samples were examined from two widely separated localities: Fambridge in the River Crouch, Essex; and Farland Point, Isle of Cumbrae, in the Firth of Clyde. The specimens from Essex were dredged from a depth of about 2 m. (below L.W.O.S.T.), and were attached to the empty shells of the European oyster,Ostrea edulis L. and to the shells ofCrepidula fornicata L. The speci-mens from the Firth of Clydewere attached to stones on sheltered parts of the shore. The animals here extended over a zone of the shore from about Chart Datum+ 2.5 ft. (0.76 m.) to about Chart Datum+ 7.5 ft. (2.29 m.): Only in very sheltered positions, such as under large boulders, did Dendrodoa occur in abundance. The two habitats were thus very different in nature, one being sublittoral on the south-east coast of Britain and the other being littoral on the north-west coast. The value of comparisons is limited by the different nature of the conditions to which the sublittoral and the littoral populations were exposed.

The observations on growth in the Clyde extended over most of 1951 and 1952, and nineteen samples were taken.

The Pycnogonida of Plymouth have had very little attention and early records are few. Of the eight species recorded in the Plymouth Marine Invertebrate Fauna in 1904, two, Nymphon gallicum and N. gracile, are synonymous, and these two are also recorded in the 1931 edition which comprises only the same eight species. The scarcity of the records shows that little search was made for the members of this group, for on revising it at the present time it is found that thirteen species certainly occur, being five more than are shown in the Marine Invertebrate Fauna. Hodgson (1910) records thirteen species from Devonshire, but these are not all the same as the thirteen now recorded. He mentions eleven from Plymouth, three of which have not been found recently. These are Pallene spectrum, Nymphon brevirostre and Ammothea laevis.

The present study evaluated shell utilization and preference of two sympatric hermit crab species, Calcinus tibicen and Clibanarius antillensis, from Ilha Galheta de Dentro, Vitória Bay, south-eastern Brazil. Distribution of individuals and use and availability of shells were estimated in the field, where micro-habitat and shell partitioning were demonstrated between the two species of crabs. Calcinus occurred in higher numbers in the infralittoral fringe and shallow subtidal, while Clibanarius was found mainly in the midlittoral zone. The crabs used shells of different architectures and sizes. Calcinus used mainly globose and low spired shells (Tegula viridula and Cymatium parthenopeum), while Clibanarius utilized predominantly the elongated and high spired ones (mainly Cerithium atratum). Clibanarius used shells with smaller volume, weight, and aperture. Free access experiments were conducted in the laboratory and showed that Calcinus and Clibanarius had a high satisfaction rate, i.e. only 50% of the crabs exchanged their shells. From those that exchanged, they chose shells with higher internal volume than that used in the field, while shell weight did not present any increase. Clibanarius was found in shells closer to the preferred ones and in a very different proportion from shell availability, contrasting to Calcinus, which followed shell availability instead of their preferences. Shell internal volume was more important as a choice factor than the weight for both hermit crab species, showing that crabs optimized shell volume in relation to shell weight in the free access experiments.

The Istanbul Strait (Bosphorus) is a part of the Turkish Straits System, connecting the Aegean Sea and the Black Sea. There are three cetacean species in the Strait, namely the harbour porpoise (Phocoena phocoena), the common dolphin (Delphinus delphis), and the bottlenose dolphin (Tursiops truncatus). To monitor the presence of the cetaceans, a fixed stereo passive acoustic monitoring system (A-tag) was deployed in the middle of the Strait from July 2009 to September 2010. In total 26,814 click trains were detected. Presence, direction and inter-click intervals of phonating cetaceans were measured. Most click trains were detected during the night time. Diel presence pattern was prominent in March and April. In spring, the cetaceans were concentrated in one specific direction from the fixed monitoring system. In contrast, they were found in all directions for the rest of the year. Short range sonar (inter-click intervals (ICIs) less than 50 ms) was commonly detected in spring. During the rest of the year ICIs could reach up to 150 ms. All these findings suggest that they were feeding or socializing in spring and mostly travelling in the other seasons. It is well known that pelagic fish such as sprat and bluefish start their migration from the Aegean Sea to the Black Sea in spring. This study suggests that the cetaceans use the middle part of the Strait for feeding on the pelagic fish in spring when the fish migration has just started.

Samples collected from power station intake screens between 1972 and 1977 have been used to study aspects of the biology of the whiting in the Severn Estuary and Bristol Channel. 0+ whiting generally started appearing in the inner estuary in July, at which time their standard length was at least 38 mm. Their numbers peaked in October and subsequently declined particularly rapidly during the wet winter of 1976/7 when salinities were frequently below 10‰. The size of 0+ whiting in the late autumn and early winter was generally less in the shallows of the Inner Severn Estuary than in neighbouring deeper waters and in the Inner Bristol Channel. Growth rates of 0 + whiting fell within the range of those recorded for the North Sea, but below those generally found in inshore waters and sea lochs on the west coast of Scotland. Following their immigration into inshore waters in the Bristol Channel and Inner Severn Estuary, young whiting became infected with the copepod parasites Lernaeocera branchialis and Clavella adunca and the metacercariae of the heterophyid digenean Cryptocotyle lingua. Prevalence of infection was less in 0+ than older fish and infection by L. branchialis caused a significant decline in condition. As whiting became larger, the main site of attachment of Clavella adunca changed gradually from the wall of the branchial chamber to the primary rakers of the first gill arch. Vertebral counts suggest that the whiting which enter the Inner Bristol Channel and Severn Estuary are not representatives of the populations found in the Irish Sea.

This paper presents information on the stomach contents of four northern bottlenose whales Hyperoodon ampullatus (Odontoceti: Ziphiidae) from the north-east Atlantic, an area for which there are few recent data on the feeding ecology of this species. Two of these whales were relatively recent strandings, a female stranded in August 1993 at Hargen (the Netherlands) and a male stranded in February 1997 on the island of Tåsinge (Denmark). Stomach content samples were also examined from a juvenile male stranded in November 1885 at Dunbar (Scotland) and a female stranded in August 1956 on the island of Texel (the Netherlands).  Food remains from the four samples consisted almost entirely of cephalopod beaks. Some fish remains were also found in the stomach of the Hargen and Tåsinge whales, and the latter also had crustacean remains in the stomach. The cephalopod prey consisted mainly of oceanic cephalopods: Gonatus sp. (probably G. fabricii, Cephalopoda: Teuthoidea), Taoniuspavo and Histioteuthis sp. for the Dunbar whale; Gonatus and Teuthowenia megalops for the Texel whale; Gonatus for the Hargen whale and Gonatus, T. megalops and Taonius pavo for the Tåsinge whale. Other prey species found in the Tåsinge specimen included the squid Histioteuthis reversa, H. arcturi, and the octopods Vampiroteuthis infernalis and Vitreledonella richardi. Based on the size of the lower beaks, the squid eaten included juvenile and mature individuals of the most important species (Gonatus and Teuthowenia megalops). The fish remains consisted of vertebrae of Gadidae and fish eye lenses (Hargen whale) and two Trisopterus otoliths (Tåsinge whale).  The results from this study are in agreement with those of previous authors in that cephalopods in general, and G. fabricii in particular, are the main prey of the northern bottlenose whale and other toothed whales in northern latitudes.

Oxygen consumption was measured in squid (Illex illecebrosus) ranging from 42·7 to 443·0 g. Ambient temperature increased from 8·3 °C to 18·2 °C during the experimental period. Resting rates were calculated by correcting for the percentage of time not spent in the resting posture. A 100 g squid resting at 13 °C has a predicted oxygen consumption of 31·3 ml/h, while a continuously swimming squid has an oxygen consumption of 125·0 ml/h. Oxygen consumption is almost directly proportional to body size. A 10° increase in environmental temperature would increase oxygen consumption for a squid of given mass by 6·7 times.

Changes in dietary lipids (fatty acids, sterols and fatty alcohols) during herbivory and coprophagy by the annelid worm Hediste (Nereis) diversicolor (O.F. Müller) were modelled in laboratory feeding experiments. The dinoflagellate Scrippsiella trochoidea (Stein) was used as the food in herbivory; faeces from the crustacean Neomysis integer (Leach) after feeding on this same alga, were used as the food in coprophagy.

Nereis is extremely efficient in its assimilation of dietary lipids and produces faeces with very low fatty acid:sterol (FAST) ratios in both herbivory and coprophagy. The net decrease in total lipid in both modes of feeding with this species suggests that annelids, where present, are as important as other invertebrate groups in affecting the flux of lipids through marine food chains.

Columbus crabs, Planes minutus (L.) (Crustacea: Brachyura) are often found on the postero-ventral surfaces of sea turtles, particularly the loggerhead Caretta caretta (L.) (Testudines: Cheloniidae). There has been a general acceptance of a hypothesis that the crabs feed upon turtle faeces. However, evidence is presented here to demonstrate that Planes has a ‘cleaning’ role, feeding on other epibionts (e.g. barnacle cyprids, parasitic amphipods) during daylight hours. At night it is likely that the crabs feed on neustonic animals (e.g. euphausids). The species is also cannibalistic.