We analysed the stomach contents of 69 silky sharks Carcharhinus falciformis, 44 blacktip sharks Carcharhinus limbatus and 24 whitenose sharks Nasolamia velox caught in the Ecuadorian Pacific from August 2003 to December 2004. Prey included bony fishes, elasmobranchs, molluscs, crustaceans and turtles, with bony fishes being the most important to the diets of all three sharks, suggesting they are piscivorous predators. Based on the index of relative importance, the C. falciformis diet includes Thunnus albacares, Thunnus sp. and Auxis thazard, as well as some squid, fish and turtles. Similarly, the C. limbatus diet was dominated by T. albacares, Exocoetus monocirrhus, A. thazard, Katsuwonus pelamis, members of the Ophichthidae family and other elasmobranchs. Meanwhile, N. velox consumed mainly Dosidicus gigas, Larimus argenteus, Cynoscion sp. and Lophiodes spilurus. There is little competition for food between these tertiary carnivores: C. limbatus prefers prey from coastal-oceanic habitats; C. falciformis consumes mostly oceanic prey and N. velox focuses on prey from coastal habitats. The lack of information on the biology of sharks in Ecuador hinders the development of appropriate management and conservation plans to protect shark resources. This study increases our knowledge and understanding of sharks in Ecuador, thus contributing to their conservation.

Reproductive cycles were studied in seven natural populations of the intertidal bivalve Perumytilus purpuratus, distributed in a latitudinal gradient of ~2400 km along the Chilean Pacific coast (20–40°S). The results, both qualitative (gametogenic stages) and quantitative (GSI and GVF), over a period of 24 months, showed that these populations presented asynchrony in the reproductive cycle. Semi-annual cycles in Iquique (20°S), Antofagasta (23°S) and Montemar (32°S), and annual cycles in Caleta Bolfin (23°S), Taltal (25°S), Tumbes (36°S) and Pucatrihue (40°S) (2010–2012) were found. The results indicate that latitude does not have an effect on the development stage, but it does on the spawning date. However, there is a relationship between the reproductive cycles and temperature fluctuations. In addition, there was a significant negative linear correlation between gonadosomatic index and sea surface temperature in the populations studied. The decrease in temperature reduces the rate of development stages and, therefore, increases the reproductive cycles from semi-annual to annual, as evidenced in bivalve samples from Taltal, along a semi-decadal period (2007–2012). From these results, we discuss the likely biological and ecosystem consequences in connection to the effects of climate change in the South Pacific.

In marine crustaceans the polynuclear aromatic hydrocarbon benzo[a]pyrene undergoes changes mediated by benzo[a]pyrene mono-oxygenase (BPM), a cytochrome P-450 dependent enzyme system requiring molecular oxygen and NADPH as a cofactor: it has now been detected in several species (see O'Hara et al. 1982).

Lophius kidneys perfused with the heparinized blood (venous) of the fish secrete urine in which total non-protein nitrogen is concentrated, magnesium highly concentrated, and chloride only slightly so or not at all. Oxygenation of the blood, or lowering the temperature of the perfusate from c. 20° to c. 5° C. does not appear to influence secretion. The blood flow through the kidneys increases with the perfusion pressure, the increase often becoming disproportionately large. The urine flow, on the other hand, above a certain critical level is largely independent of changes in perfusion pressure.

Alectona species which bore into the scleraxis of several colonies of Corallium elatius and the stem of a stylasterid coral, Distichopora sp. have been studied. The genus Alectona consists of rarely collected species. Five species, of the eight known for the genus, are here recorded. Two new species of Alectona sorrentini and A. microspiculata and one uncertain species are described.

In recent reefs Cliona species are the predominant boring sponges while Alectona and Thoosa were common in the Eocene/Miocene coral reefs. The deep precious red coral communities of the western Pacific may be interpreted as refuge habitats of these ancient boring sponges.

Collections of bottom-living animals from the continental slope of the northern Bay of Biscay contain a new species of Oligobrachia; this increases the number of species of Oligobrachia known from the North Atlantic to five. Oligobrachiids are quite frequently found incubating embryos and five individuals of the new species carry embryos. Oligobrachia embryos have been studied morphologically already (Ivanov, 1957, 1975; Southward & Southward, 1963; Brattegard, 1966; Ivanov & Gureeva, 1976) and should prove useful material for experimental studies in future. Incubation is also known in the family Siboglinidae, but neither embryos nor larvae have been seen in any other pogonophoran families. The Biscay collections also contain additional specimens of Oligobrachia ivanovi and these have been useful in revising the description of this rather rare species.

The three lobed paragnath of Palaemon serratus (Pennant) contains numerous rosette-type tegumental glands often arranged in clusters of up to ten glands. Each gland is made up of around ten cells most of which stain deeply with toluidine blue and whose contents have a reticulate appearance in electron micrographs. One, or occasionally two, cells stain faintly and have a fine granular appearance in electron micrographs. The central region of each gland contains the main drainage duct together with feeder canals from the vesicular storage areas. The actively secreting region of each cell is peripheral and typified by abundant rough endoplasmic reticulum and Golgi apparatus. There are nerves adjacent to the glands and their contents are probably discharged in response to a food stimulus. The structure and possible function of the glands are discussed in relation to those of other species The secretions could act as a lubricant and as a binding agent to aid in the ingestion of particulate food. There is no evidence for any direct digestive function.

The effect of light upon plant growth is a problem which has attracted many workers since the discovery of Priestly, in 1771, that a plant could purify fixed air, carbon dioxide, which was followed by the supplementary work of Ingen-Housz and Senebier, who showed that the phenomenon was associated with the nourishment of the plant, and took place only in sunlight and through the agency of the green portions of the plant.

The present paper continues the account of my experiments ou the capacity of fishes to form conditioned responses towards definite stimuli under strict experimental control. No change has been made in the method of recording the results except in the section on auditory discrimination in the wrasse. This slight variation is explained in the appropriate place.

All the experiments described in this part belong to Section A of the previous paper (1), in which food is the unconditioned stimulus. The work which has been carried out in Section B will receive fuller treatment at a later date.

The behaviour of lugworms in sand was studied by recording kymographically the water movements through their burrows and observing the timing of defaecation. The worms ranged in weight from 2 6 to 186 g. Three types of apparatus were used, differing in the amount of space allowed to the worms.

The worms often traced a characteristic pattern described elsewhere, consisting of regularly spaced diphasic excursions of the irrigation graph with a defaecation on the apex of each first phase. The interval between excursions was about 15–20 min. for worms weighing about 3 g. and increased with size to about 40 min.

The worms sometimes traced similar periodic bursts of irrigation activity without defaecation.

Many of the tracings were confused in pattern. The worms often defaecated—sometimes sporadically, sometimes at regular intervals—in the absence of the characteristic diphasic excursions. Restriction of a worm to a small space appears to favour the production of confused tracings.

The relation between the irrigation patterns and the timing of defaecation is discussed.

The effect of algal food concentration, substratum, light, salinity, cyprid density and ‘footprints’, cyprid age, films of organic biopolymers, bacteria and diatoms on the settlement of Balanus reticulatus cyprids were studied. The algal food quantity (from 7×104 to 4×105 cells ml−1) fed to nauplii had a significant effect on the settlement. Cyprids failed to settle on glass surfaces but would settle on polystyrene. Light, cyprid ‘footprints’ and age significantly affected the settlement, however, salinity (from 20 to 40 psu) and cyprid density (from 5 to 200 per 5 ml of seawater) had no effect on the settlement. Films of organic polymers, bacteria, and diatoms inhibited the settlement compared to control. It is suggested that cyprids of B. reticulatus can serve as an appropriate test material for antifouling bioassays in those areas where the former forms a dominant species.

Recent studies of the large cheilostome bryozoan genus Scrupocellaria have shown a greater degree of taxonomically informative morphological variation in zooids, opesia, and polymorphic structures than previously recognized. Only one subgenus has been named within the genus, Retiscrupocellaria d'Hondt, 1988, erected for Scrupocellaria jolloisii. In this work we further analyse S. jolloisii and its related species, resurrecting an earlier genus name, Licornia van Beneden, 1850 for Licornia jolloisii, and nine relatives, L. annectens, L. cervicornis, L. cyclostoma, L. diadema, L. ferox, L. gaspari, L. longispinosa, L. macropora, and L. prolata. Licornia jolloisii was originally described from the Red Sea, and most species of the genus occur in the Indo-Pacific region. The species, however, has now been found in the Western Atlantic, in the Florida Keys, US, and in Bahia de Todos Santos, Brazil.

Recordings of a group of foraging sperm whales usually result in a mixture of clicks from different animals. To analyse the click sequences of individual whales these clicks need to be separated, and for this an automatic classifier would be preferred. Here we study the use of a radial basis function network to perform the separation. The neural network's ability to discriminate between different whales was tested with six data sets of individually diving males. The data consisted of five shorter click trains and one complete dive which was especially important to evaluate the capacity of the network to generalize. The network was trained with characteristics extracted from the six click series with the help of a wavelet packet-based local discriminant basis. The selected features were separated in a training set containing 50 clicks of each data set and a validation set with the remaining clicks. After the network was trained it could correctly classify around 90% of the short click series, while for the entire dive this percentage was around 78%.

Laboratory breeding of the dog-whelk, Nucella lapillus, has established that the male-sterilizing Dumpton Syndrome (DS)—underdevelopment, or non-development (aphally), of the penis, incomplete formation (non-closure) of the vas deferens, resulting in a split prostate—can be readily observed in male F1 progeny. Cultivated under high ambient concentrations of the antifouling agent tributyltin (TBT), DS-carrying females can be recognized by their lesser degree of masculinization (imposex): sterilization is thereby avoided. When Dumpton females are crossed, under high ambient TBT, with individuals from a non-DS-affected population (Bude, North Cornwall) DS is absent from both sexes. Crosses of these F1 progeny result in F2 progeny exhibiting the classic DS symptoms in both sexes. A Mendelian mechanism for DS inheritance is suggested by the data.

There are 290 described species in the tube-dwelling family Sabellidae (Fauchald, 1977), but our knowledge of their reproductive biology is limited, in whole or in part, to no more than 30 species (McEuen, Wu & Chia, 1983; Knight-Jones & Bowden, 1984). In the monogeneric subfamily Myxicolinae, the diminutive Myxicola aesthetica (=dinardensis) (Claparède) is known to undergo scissiparity (Caullery & Mesnil, 1920; Okada, 1934; Knight-Jones & Bowden, 1984). For the larger species, M. infundibulum (Reinier), the only information on reproduction is: an illustration of the sperm (Claparede, 1870), the conclusion that it spawns during the autumn in the Bay of Fundy and adjacent waters (MacKay, 1977 a, b), and that autotomy has not been observed and regeneration is limited to the branchial plume (Wells, 1952).

(1) The asymmetrical development in Hydroides opercula is due to the growth difference between two sides in the same kind of organs. The presence of a functional organ holds its mate in check. Therefore, taking off the functional operculum results in the development of the rudimentary side.

(2) This phenomenon of compensatory regulation cannot be considered to be brought about by a nervous reflex set in motion by the stimulation of damaged nerves in the operated operculum, since, for example, the inhibitory influence to a certain extent depends on the degrees of injury.

(3) It is also not proved to be due to the production of a certain chemical substance which stimulates the rudimentary organ to grow, while the wound itself affects directly the inhibitory action of the functional operculum.

(4) The inhibitory influence is only localized in the operculum and not outside of it. Therefore, cutting off the gill filaments or other parts of the body does not bring a reversal of asymmetry.

(5) Within the limit of the operculum there is no special centre of the inhibitory influence, which depends on the intactness of the internal constitution of the organ. Those peripheral parts outside the limit of direct blood supply can be cut off, without the resulting reversal of asymmetry. A simple puncturing with a fine needle also has no effect. But greater injury accompanied by an outflow of blood always starts the rudimentary organ developing.

(6) The functional operculurn has no regenerative capacity, while the rudimentary one still has. The injured operculum is thrown off sooner or later from the body, and a new start repeats from the beginning the original development. By accelerating this regenerative development of the old functional organ, or properly controlling the growth of the rudimentary organ on the opposite side, a symmetrical animal with two large opercula can easily be derived. On the other hand, if both rudiments antagonistically check each other's development, a symmetrical animal with two small rudimentary opercula is produced.

(7) Since, however, either the right or the left or even both rudiments can be made to develop into a functional organ, the inhibitory influence must act at first on both alike, unless a threshold value is assumed. In the present species of Polychsete it is as a rule the right-handed one that grows more quickly than the other.

(8) With regard to the nature of the asymmetry in Hydroides it seems to be quite different from that in the male Gelasimus in which the asymmetry of the chelas is said to be derived from the symmetrical condition relatively late in development, and the relation, once attained, becomes fixed.

(9) In Hydroides norvegica at least, the opercula show a tendency to right-handed growth from the beginning of their development, but this condition of asymmetry is very unstable and is easily reversible by an external influence even in the adult state, i.e. there is no critical stage at which it is irreversibly determined.

The swimming behaviour of Corophium volutator from Wales and East Anglia was investigated to establish whether differences apparent from two previous studies are real or artefacts of the different techniques used. Swimming C. volutator were caught in a Welsh estuary in the summer, but only rarely in the autumn and winter, and in both daylight and darkness. In simulated tidal conditions in the laboratory C. volutator from two sites in East Anglia never swam, while those from Wales swam whenever the substratum was immersed, in daylight and darkness, mostly on the ebb tide and in winter. The unnatural swimming in winter may have been stimulated by laboratory conditions, but the East Anglian amphipods were not so affected. The tidal swimming rhythm is different to east coast C. volutator which only swim at night. This difference may be related to the time of spring tides, when most swimming occurs. In Wales high water of spring tides may occur only in daylight in summer and nocturnal swimming may not be possible. The ebb tide swimming by C. volutator in Wales contrasts with the flood and ebb swimming of east coast amphipods and may reflect differences in their habitats. The former were collected close to the sea while the latter were 15 km up a narrow estuary and may represent a sub-population of amphipods with a disposition to swim early (on the flood tide) enabling them to colonise upstream habitats.

The largest recorded specimen of the mesopelagic scyphomedusa, Stygiomedusa fabulosa Russell 1959, was taken in the North Atlantic (49° 53' N, 33° 18' W). Umbrella diameter was 140 cm with an oral arm length of 164 cm. This specimen is morphologically intermediate between the nominal species of the genus, S. fabulosa and S. stauchi. This suggests that S. stauchi is not a distinct species. The midwater fish Thalassobathia peligica was captured in the same haul and could live in association with large scyphomedusae.

A hydraulic dredge survey was conducted during January – June 1994 in north-west, north and east Iceland, to provide a first assessment of ocean quahog, Arctica islandica (Mollusca: Pelecypoda) resources in these areas. Ocean quahog was found in significant concentrations and high density. The combined high-density areas were 91.7 km2 with a minimum biomass (live weight) of 304.80 tonnes. Information on population structure and meat yield were also provided. The population in the areas was characterized by unimodal size distributions comprised of mostly larger-sized individuals. Most quahogs were between 70 and 90 mm with no individuals <17 mm which might be due to the selectivity of the dredge or because of poor recruitment in the population. Little difference was observed when comparing the mean shell length for the quahogs from the three areas. The mean shell length in the north-west area was 75.4 mm and 74.8 mm in the north and east areas. The shell length frequency distribution for the north-west area was different in shape from the two others which were not significantly different from each other. Mean quahog meat yields in the areas were from 30.1 to 33%. The meat yield was highest in the 50.55 mm size class in all areas.

Dinophysis sacculus (Dinophyceae) is a potential producer of diarrhoeic shellfish poisoning (DSP). Population dynamics of this dinoflagellate was followed in the Varano lagoon, south-east Italy, with the objective of determining the seasonal abundance of D. sacculus and the relationship to environmental factors. The seasonal occurrence of this dinoflagellate showed a rather wide temporal distribution and increases in cell numbers were observed in late June and November. Dinophysis numbers seasonal changes appeared to be dependent on chemico–physical factors and dissolved nutrients. Three morphologically distinct forms of D. sacculus were found during the sampling period (March 1997–February 1998) related to the life history of the species and not to environmental conditions. In this mussel fishery, D. sacculus presence and proliferation were not associated with biotoxicity.