Much is unknown about humpback whale (Megaptera novaeangliae) song. The behaviour is limited almost exclusively to males, occurs almost exclusively on the calving grounds and is identical within a population, although it changes periodically throughout the season. Much of current thinking associates humpback whale song with breeding, although it is not clear if it is intended to attract a mate, fend off challengers, or a combination of the two. There is, however, very little information on the internal biology of these large, sea-going mammals, so the majority of hypotheses have not considered much in the way of physiological mechanisms. Nonetheless, we believe that there is enough information available to infer that a seasonal process of neurological development and atrophy similar to that found in other animals may be present in humpback whales. We believe this explains why humpback whale song is not produced between breeding seasons and also why it does not vary between seasons, while it does so within a season. It also adds additional weight to the idea that humpback whale song is an honest signal of fitness to a potential mate or competitor.

The population density, annual gametogenic cycle, and size at sexual maturity of two vermetid species, Eualetes tulipa (invasive) and Dendropoma corrodens was studied in the southern Caribbean at the Planta Centro power plant intake channel and at Punta Mayorquina, Morrocoy National Park, respectively. Minimal size of mature females of E. tulipa and D. corrodens was 5.0 and 0.7 cm in body length respectively. The gonad represented between 44 to 47% of total body length, while it represented between 15 to 18% of total body volume (for both males and females). Gonad volume was significantly related to total body volume. A significant quadratic relationship between the number of capsules and female body volume was obtained for E. tulipa, indicating that females measuring 6–10 cm in body length are those that have the highest number of egg capsules. Females larger than 11 cm have a lower fecundity in terms of brooded capsules. Gonad sections of males and females of both species showed that several gametogenesis stages are simultaneous within the same individual. In the female, germ cells, oogoniums and primary oocytes with yolk granules were observed simultaneously. In the male, the spermatogonium, primary and secondary spermatocytes, spermatids and sperm cells were also observed within one gonad. The same pattern was observed throughout the year, showing no maturation/resting period or annual cycle. The area covered by D. corrodens was about 700 m2 with a mean density of 13,000 ind/m2. The area covered by the invasive E. tulipa was at least about 1000 m2, with a density of 27,000 to 29,000 ind/m2 in the first 3 m of depth. A follow up of the E. tulipa population showed that its density is increasing in time and has doubled in 20 years. This population increment could be related to an increase in organic suspended matter as evidenced in the region.

A species believed to be more primitive than C. natans (Grontved) (type species of Calliacantha Leadbeater) has been described and illustrated by means of light and electron microscopy of dry whole mounts prepared in situ from freshly gathered sea water, mainly in South Africa but supplemented by one gathering from Britain.

To describe the age, growth, mortality and distribution of the garfish, Belone euxini and differences in these parameters from other populations, monthly samplings were conducted between December 2011 and July 2013 in the south-east Black Sea. Garfish catch decreased to its lowest levels in spring months, especially after May, and it was completely finished by the summer months. The mean total length (TL) of the female was significantly greater than the mean TL of the male (P < 0.05). The sex-ratio of female:male with size was skewed towards males up to 38 cm length-class, and skewed towards females above the 38 cm class (P < 0.05). The growth pattern of garfish was described by goodness of fit of the data and biological interpretation of growth parameters. The exponential (females: L∞ = 88.3 cm TL, K = 0.108 yr−1, males: L∞ = 71.9 cm TL, K = 0.151 yr−1) and von Bertalanffy (females: L∞ = 81.6 cm TL, K = 0.125 yr−1, t0 = −2.25 year, males: L∞ = 81.6 cm TL, K = 0.125 yr−1, t0 = −2.13 year) models were considered the most suitable growth models. Total instantaneous mortality rate, Z, was estimated as 1.04 yr−1 for females and 1.24 yr−1 for males. Instantaneous natural mortality ratio, M, was estimated higher for males than for females. The exploitation rate of both sexes was also higher than the optimum exploitation (E = 0.5) criterion, which is indicative of overfishing of the garfish population.

A steroid that binds with mammalian oestradiol-17β antibody has been detected in Calanus helgolandicus Claus, collected from Plymouth Sound, and in Calanus finmarchicus Gunnerus captured off the coast of Norway. The specificity of the antibody, together with the chromatographic behaviour of the steroid on Sephadex LH-20, supports the view that the compound is the sex hormone oestradiol-17β (E2). The antibody has been used in measuring the amounts of E2 in the animals by radioimmunoassay, a technique not previously employed in studies with zooplankton and therefore described in detail.

Ten stations were sampled in the shallow-water sand habitat of Strangford Lough using a naturalist's dredge. Sediment samples were analysed to determine median diameter (ranging from 1·13 to 3·23 ø), Phi quartile deviation (ranging from 0·17 to 0·65 ø) and Phi quartile skewness (ranging from –0·11 to –0·04 ø).

Twenty-two species of amphipod belonging to thirteen families were identified; ten species were new records for Strangford Lough and the Family Phoxocephalidae was recorded for the first time. The average number of species per station was nine and average abundance was 660 amphipods per station. The most frequently occurring species was the caprellid Phtisica marina (present in 90% of the samples); the overall dominant species was the corophiid Corophium crassicorne representing 52% of all specimens recorded.

The young stages of the members of the family Eulimidæ are little known, the only reference to any species apparently being that of Loven (1844) who briefly notes and figures a veliger which he attributes to Eulima distorta (=Balcis devians). This has a very oblique shell and was probably a week or two old. A comparison of this figure with the apex of Balcis devians from Plymouth and its larvæ in the plankton makes one rather uncertain of its identity but shows that even in those early times it was known that a Eulima could remain some time in the plankton as a veliger.

The success of planktonic copepods in aquatic environments is dependent on efficient sensing of their three-dimensional surroundings. The detection of external cues is of importance for the localization of other organisms (prey, predators and mates), and is mediated by an array of mechano- and chemoreceptors located on the paired antennules (A1).

We investigated the morphology and distribution pattern of A1 sensory structures in the adult female of Clausocalanus furcatus (Copepoda: Calanoida) using different techniques (camera lucida, scanning and transmission electron microscopy and laser scanning confocal microscopy) each focusing on a specific aspect of the structures analysed. Integration of the information collected shows that C. furcatus possesses an array of mechanical, chemical and dual-function sensors over its A1, by which the copepod can detect different stimuli from the environment. Results are discussed in the light of the unique swimming behaviour displayed by this widespread epipelagic copepod.

These notes are intended to be explanatory of the record of tow-net stages of Teleosteans kept by Mr. S. D. Scott and myself. Although my own name appears alone under the title, it must be understood that the observations were in the sole charge of Mr. Scott until the beginning of March. The record of the 5th April is also Mr. Scott's. The rest were kept by myself. The credit of any scientific result that may accrue from the observations previous to the 30th March belongs therefore solely to Mr. Scott, since his notes and figures are so complete as to render my own share of this part of the work a very simple one.

This journal is not designed for the publication of such profusely illustrated papers as are best suited for the explanation of the earliest stages of Teleosteans. It so happens that in the present instance I am able in most cases to refer either to figures already published, or to others now in the press. A series of notes made at Professor Marion's laboratory at Endoûme, Marseilles, was prepared for the press during 1897. Observations made at Plymouth during the same period were found to have an obvious bearing on the subject-matter of my researches at Marseilles, and by the generous permission of Professor Marion I have been allowed to include in a paper shortly to be published in the Annales du Musée de Marseille a number of drawings made from Playmouth specimens. I am therefore able in many instances to eke out somewhat inadequate descriptions by references to figures in the Annales.

Three new species of echinoderid kinorhynchs are described from Daidokutsu, a submarine cave in Ryukyu Islands, Japan. Echinoderes gama sp. nov. is characterized by the presence of middorsal acicular spines on segments 4–8; lateroventral acicular spines on segments 7–9; lateroventral tubes on segment 5; sublateral tubes on segment 8; laterodorsal tubes on segment 10; and type-2 gland cell outlets in subdorsal and lateroventral position on segment 2. Echinoderes kajiharai sp. nov. is defined by the presence of middorsal acicular spines on segments 4, 6, 8; lateral accessory acicular spines on segment 9; lateroventral acicular spines on segments 6–8; lateroventral tubes on segments 2 and 5; midlateral tubes on segment 10; and type-2 gland cell outlets in laterodorsal position on segments 2 and 5, and subdorsal position on segments 8 and 9. Echinoderes uozumii sp. nov. is characterized by the presence of middorsal acicular spines on segments 4 and 6; lateroventral acicular spines on segments 6–9; lateroventral tubes on segments 2 and 5; sublateral tubes on segment 8; laterodorsal tubes on segment 10; type-2 gland cell outlets in subdorsal and lateral accessory position on segment 2; and blunt, short pectinate fringe teeth of primary pectinate fringe on segment 1. In addition, the Echinoderes multiporus species group including E. kajiharai sp. nov., and the Echinoderes bispinosus species group including E. uozumii sp. nov. are established. Furthermore, the distribution of the two species groups and the origin of Echinoderes species in Daidokutsu are discussed.

Bottlenose dolphins (Tursiops truncatus) have been surveyed for at least two decades on the southern Brazilian coast. However, little is known about their distribution and habitat use in lower latitudes of the South-western Atlantic Ocean. Aiming to study the movements and distribution of the species along the south-eastern Brazilian coast, we made a comparison of photo-identified individuals of the species catalogued in 21 cruises conducted between 2012 and 2015. Additionally, we performed stable isotope analyses of carbon and nitrogen in skin samples (N = 35) to provide some insights of dolphin habitat use and trophic ecology through comparisons among individuals of distinct surveyed sectors (northern and southern) and sex. A total of 177 individuals were identified. Re-sightings (N = 24) occurred at intervals from 82 to 979 days at distances from 7 to 179 km. No individual was sighted in both sectors, suggesting spatial segregation. Isotopic comparisons showed no significant differences in carbon and nitrogen signatures between distinct sectors. However, ecological divergences were found when we divided the samples by gender. Wider isotopic niches were found for the northern bottlenose dolphins vs the southern ones, which could be related to temporal and spatial variation in the availability of resources, as well as possible differences in the home ranges of males and females in each region. This study represents a preliminary evaluation of ecological aspects of bottlenose dolphins along the Brazilian south-eastern coast, however, long-term studies on the feeding ecology and habitat use of this species are important to further improve our knowledge.

Cetaceans are prone to collisions with fast vessels, and in areas of high cetacean and vessel density such as in the Canary Islands, the sperm whale (Physeter macrocephalus) is of great concern. Sperm whales are highly vocal and can be localized with passive sonar, but, when at or near the surface, they tend to stop vocalizing, i.e. when they are most at risk. Regrettably, ship-borne active solutions have proven inefficient due to the short detection range and the ships' high-speeds. Our objective in this paper is to evaluate the efficiency of an original passive sonar solution that would use vocalizing whale clicks at depth as acoustic sources to detect silent whales. This solution could be a non-invasive complementary component of a more complex passive localization whale anti-collision system. To meet this aim, a simulation tool for 3D acoustic propagation was designed in which a wideband Nx2D ray solution of the wave equation simulates a passive solution consisting of an arbitrary number of active acoustic sources, an illuminated object, and a receiver, all positioned in a three-dimensional space with arbitrary bathymetry. Both curved and straight ray solutions were implemented, the latter providing greater computational speeds at the expense of temporal and angular precision. The software recreates the resulting sound mixture of direct, reverberated and target back-scattered signals arriving at the array sensors for any array configuration, any number of sources and one target. Simulations show the application of the concept for the Canary Islands, with a detection range upper bound of the order of one kilometre.

The activity rhythm of the cold seep shrimp Alvinocaris stactophila from the Gulf of Mexico slope (650 m depth) was investigated in the laboratory in relation to an artificial 12 h light-dark regime. Animals were sampled with a submersible and transferred into individual aquaria where their activity was monitored for 5 d by taking digital video snapshots every 30 s. An observer analysed the footage by counting the number of times an animal crossed two perpendicular lines drawn on a PC screen per 30 min interval. Resulting time series were represented over consecutive days and the waveform analysis was used to precisely assess the phase (i.e. the peak timing) and its limits (i.e. onset and offset) in relation to light ON and OFF. The majority (73%) of animals showed a marked nocturnal pattern of activity with number of movements close to zero during the photophase. Waveform analysis showed that the behavioural transition from activity to inactivity after light ON occurred within approximately 1 h. Considering the general lack of knowledge on the regulation of activity rhythms of crustaceans from subtidal areas, the present data provide a new insight on the role played by light in the regulation of animal activity rhythm in deep-water environments such as those of the cold seeps in the Gulf of Mexico.

The deep brine pools of the Red Sea comprise extreme, inhospitable habitats yet house microbial communities that potentially may fuel adjacent fauna. We here describe a novel bivalve from a deep-sea (1525 m) brine pool in the Red Sea, where conditions of high salinity, lowered pH, partial anoxia and high temperatures are prevalent. Remotely operated vehicle (ROV) footage showed that the bivalves were present in a narrow (20 cm) band along the rim of the brine pool, suggesting that it is not only tolerant of such extreme conditions but is also limited to them. The bivalve is a member of the Corbulidae and named Apachecorbula muriatica gen. et sp. nov. The shell is atypical of the family in being modioliform and thin. The semi-infaunal habit is seen in ROV images and reflected in the anatomy by the lack of siphons. The ctenidia are large and typical of a suspension feeding bivalve, but the absence of ‘guard cilia’ and the greatly reduced labial palps suggest that it is non-selective as a response to low food availability. It is proposed that the low body mass observed is a consequence of the extreme habitat and low food availability. It is postulated that the observed morphology of Apachecorbula is a result of paedomorphosis driven by the effects of the extreme environment on growth but is in part mitigated by the absence of high predation pressures.

Post-traumatic regeneration of arms in Cephalopods is a common occurrence. It was described by Aristotle and, in more modern times, by Steenstrup (1856). Féral (1978) summarizes the information on regeneration of arms, tentacles and suckers in cephalopods. He reports only one case, experimental, involving a Sepiolidae species, namely Sepiola atlantica.

This paper gives an account of regeneration of the copulatory arm in three wild-caught male sepiolid squids, two of which were Sepietta oweniana (d'Orbigny, 1841) and one Sepiola ligulata Naef, 1912 (Sepiolidae: Sepiolinae). The copulatory arm, or hectocotylus, is the left dorsal arm in Sepiolinae. It represents a most important means of species identification (Naef, 1923; Bello, in press). The squids were caught by bottom trawl in the southern Adriatic Sea during routine sampling. Measurements and observations were made on preserved specimens.

This paper describes the organism–organism relationship between a bivalve host and larval digeneans. The studied population of the stout razor clam Tagelus plebeius from the mixohaline Mar Chiquita lagoon (37° 32′S 57° 19′W) showed 100% of prevalence of infection by a larval digenean (metacercaria) of the family Gymnophallidae. The larvae occupied the extrapallial space just below the hinge of the bivalve. The tissue reaction against larval digeneans by T. plebeius consisted of hyperplasia and metaplasia of the outer layer of the mantle epithelium adjacent to parasites, forming an invagination to generate a sac that surrounded gymnophallid larvae. According to the intensity of infection, each sac progressively enlarged to harbour a variable number of larvae. In highly infected clams, a great number of sacs are formed. Eventually, the older sacs containing larvae may become closed, losing their communication with the extrapallial space and sinking into the dorsal part of the visceral mass. Larvae within sacs grow and remain alive until they reach an appropriate definitive bird vertebrate host. Older lesions commonly showed remains of dead larvae which had undergone resorption. As a result, an orange to brownish amorphous material accumulated in the space once occupied by the larvae leaving conspicuous orange marks on the inner surface of the valves. In some cases, calcifications in the form of pearls or blisters were observed.

Polychaete worms obtained by RRS ‘Discovery’ from 200 to 4850 m north-west of Africa in 1979 contained 24 species of which five: Macellicephala violacea, Bathyeliosona abyssicola, Laetmonice filicornis, Maldanella harai and Potamilla torelli were present in the abyssal zone (>2000 m). Macellicephala violacea is widely distributed in the Arctic and the present record is the southern-most record of this species. Fifteen species were recorded from the bathyal zone, many of which have a wide distribution in the oceans. A Neopolynoe species from the bathyal zone is new to science.

Wounds caused by predation and/or physical disturbances to sessile marine animals are common. Consequently, these organisms had to develop strategies to endure such injuries and survive in such a dynamic environment. Sponges are known to possess one of the greatest capacities of regeneration among living metazoans, but this feature has been largely studied only in Demospongiae. In Calcarea, very few species have been investigated. Hence, we analysed the regeneration and speed rates from two regions (osculum and choanosome) of the body of a calcareous sponge: Ernstia sp. Only the osculum regenerated until the end of the experiment, while the choanosome simply cicatrized. Calcareous sponges seem to have a polarized regeneration closely related to their external morphology and level of individuality and integration. A brief review of the regeneration capacity in Calcarea is presented.

We studied biochemical characteristics and the response to low salinity at short and long-term after feeding of alkaline phosphatase (AP) activity in hepatopancreas of the osmoregulator crab Neohelice granulata from Mar Chiquita coastal lagoon (Buenos Aires Province, Argentina) (37°32′–37°45′S 57°19′–57°26′W). The hepatopancreas exhibited a levamisole-insensitive and a levamisole-sensitive AP activity with distinct characteristics. Levamisole-insensitive activity was similar within the range of pH 7.4–9.0 and exhibited a Michaelis–Menten kinetics. Levamisole-sensitive AP activity appeared to be maximal at pH 8.5 and appeared to exhibit an allosteric kinetics. In crabs acclimated to 10 psu (hyper-regulation conditions) levamisole-insensitive and levamisole-sensitive AP activity increased (about 16-fold) over time from short term (2–4 h) to long term (120 h) after feeding while no changes occurred in crabs acclimated to 35 psu (osmoconforming conditions). The changes of AP activity along with the higher values at 120 h after feeding in 10 psu compared with those in 35 psu, and the concomitant changes in proteolytic activity, suggest a role of AP in digestive and metabolic adjustments at the biochemical level upon hyper-regulatory conditions.

Two new species of Poecilosclerida Crella (Crella) aurantiaca sp. nov. (Crellidae) and Mycale (Aegogropila) denticulata sp. nov. (Mycalidae) are described on the basis of material collected during the XX Italian Expedition (2004–2005) in Antarctica. Crella (Crella) aurantiaca sp. nov. is based on presence of acanthostyles of two size-categories. Mycale (Aegogropila) denticulata sp. nov. is characterized by the presence of palmate anisochelae and styles.