Life-history characteristics such as growth, mortality, and size at sexual maturity of the seahorse Hippocampus reidi were investigated in situ in north-eastern Brazil from August 2006 to July 2007. The von Bertalanffy growth constant K was estimated at 1.195 year−1 and L∞ was set as 20 cm according to Taylor's relationship, using a Lmax of 19 cm. The smallest male with a brood pouch and the smallest male with a fully mature pouch measured 9 and 9.5 cm (height), respectively, while the smallest mature female measured 8.8 cm. Appropriate reproductive individuals were recorded throughout the study, with peaks from May to November. The size of first effective reproduction (carrying embryos) was 12.4 cm for males, a value higher than previously reported. Estimated instantaneous rate of natural mortality ranged from 1.43 to 1.58 year−1. The estimated life span for the species was 30 months.

During a study of the reproductive cycle of a subtidal population of Chaetozone setosa Malmgren at an 80 m station off the Northumberland coast (Christie, 1981), the discovery of morphological and reproductive differences in an intertidal population lead to an extended comparative study of three Northumberland populations. The two additional populations chosen for comparison are situated at Low Newton by the Sea and Holy Island, Northumberland. All three populations are located within a maximum distance of 65 km from each other which makes these populations very close on a geographical scale.

In the present study, chthamalid barnacles of the Persian Gulf and Gulf of Oman were collected from the coastal zone of Iran. Extensive collecting of different habitat types resulted in finding two species: Chthamalus barnesi and Microeuraphia permitini. In addition to the Persian Gulf and Gulf of Oman, the former species was also collected from the Red Sea and Gulf of Aden. Both species are described and compared for their key characters with some representative members of the genera from other parts of the world.

Ontogenesis of the eyestalk structures in Palaemon serratus has been studied during the larval and postlarval life by means of scanning electron microscopy (SEM) and light microscopy (LM). At hatching, a larval sensory pore is observed in the zoea. The organ of Bellonci is present with its typical onion bodies. During larval life, this organ grows and differentiates. Vacuolization in the organ of Bellonci starts in stage 4. At the same time, the giant neuron appears, but the sinus gland cannot be recognized before stage 5.

During larval life, vesicular cells are present in the optic medullae with an increase during stages 4 and 5. The differentiation of the neurosecretory cells of MEX (medulla externa X-organ) and MTGX (medulla terminalis ganglionaris X-organ) occurs with metamorphosis. The main sensory pore appears with metamorphosis and becomes clearly visible in postlarval life.

The movements of the structures, which occupy different positions in larvae and adults, are described in relation to the longitudinal axis of the eyestalk. A schematic representation explains the torsion of the eyestalk and the dynamics and growth during the formation of the eyestalk structures.

During the year 1918 several young fish brought in alive from the tow-nets were kept in small aërated aquaria at an even temperature and fed on plankton. In this way feeding habits were noted and some post-larval fish went through a metamorphosis into the adult form, notably Labrus bergylta the Ballan Wrasse, Solea vulgaris the Sole, Solea lascaris the Lemon Sole, and three species of Lepadogaster. Young Whiting and Pollack were also kept alive for some months and fed eagerly on most of the food that was given to them.

A cytochrome P-450-dependent benzo[a]pyrene mono-oxygenase enzyme system (BPM) has been identified and partially characterized in males of the shore crab Carcinus maenas (L.). Apparent Km values obtained at 30 °C using microsomal preparations from the antennary glands of animals collected during summer were in the range 1.61–2.11 µM. The cytochrome P-450 content was 0·022 nmol/mg microsomal protein when BPM activity in the same preparation was 0·085 nmol/mg protein/min.

A numerical model is used to demonstrate wave trapping of the diurnal tides on Porcupine Bank and Rockall Bank. These waves have wave lengths of about 300 km and travel along the sloping topography with shallow water on their right. On the slopes of Porcupine Bank the shorter period K1 wave has a longer wavelength than the O1 wave and so here the trapped diurnal spring-neap signal propagates in a direction which is opposite to the phase velocity.

Here we report novel data on the ecology and diversity of West African estuarine biological communities, with emphasis on the opisthobranch gastropod, Haminoea orbignyana. Macrofaunal samples were obtained from five intertidal flats within Bodo Creek in the lower Niger Delta during two years (May 2006–April 2008) to investigate diversity and community assemblages of epimacrofauna. A total of 601 individuals belonging to 18 species were recorded, with density varying between 4 ind.m−2 and 660 ind.m−2. Gastropods (predominantly Pachymelania aurita and H. orbignyana) accounted for 92.3% of the community abundance, followed by malacostraca crustaceans (7.7%). Diversity varied (P < 0.05) between locations, with the mangrove swamp station having higher richness, diversity and evenness values than the open intertidal flat locations. The species H. orbignyana was only found on downstream sampling sites reaching a maximum density of 52 ind.m−2. The species seems to recruit during November/December and likely attains a maximum life span of about 18 months.

Length–weight relationships, sex-ratio, maturity patterns, size at first maturity, reproductive outputs, fecundity and spawning period of horned octopus Eledone cirrhosa in north-west Iberian coast are presented for the first time. Samples were collected between February 2009 and July 2011 in four fishing ports along the north-west Iberian coast: Burela in north Galician waters (NGW), Ribeira or Bueu in western Galician waters (WGW), and Aveiro in western Portuguese waters (WPW). A total of 4127 individuals (1042 males, 3079 females and six undetermined) were sampled. Individuals ranged from 45 to 191 mm dorsal mantle length (ML) and 15–1159 g body weight (BW). The overall sex-ratio was biased towards females, accounting for 74.71% of whole sample. Main spawning season of this species in north-western Iberian waters extends from May to June. Size at first maturity (ML50%) of males was 108.9 mm in NGW, 99.25 mm in WGW, and 91.4 mm in WPW, whereas ML50% for females were 134.5 mm, 121.4 mm and 100.8 mm, respectively. Potential fecundity was 2452.88 ± 36.4 oocytes per ovary (N = 697). Mean oocyte length was 3.89 ± 0.025 mm (N = 697). The average number of fully developed spermatophores in mature males was 86.55 ± 1.9 (N = 223) with a mean length of 44.97 ± 0.29 mm (N = 224). Potential fecundity in females was significantly (P < 0.05) correlated with ML and BW. Results obtained suggest that energy for gonad growth comes from the diet rather than endogenous reserves.

In a previous paper (Lebour, 1933) the eggs and larvæ of Philbertia (Comarmondia) gracilis were described, showing lens-shaped sessile eggcapsules and a planktonic larva with elaborately sculptured shell and large brightly spotted velum, which remained as a veliger until it had attained several whorls and was of a large size before metamorphosis. Lens-shaped capsules are apparently typical of the group (Jeffreys, 1867, and observations at Plymouth) and finely sculptured embryonic shells with several whorls are already known in many species (Jeffreys, 1867; Cossmann, 1895; Thiele, 1929). Researches in the Plymouth plankton show that members of this family are common and are some of the largest and most conspicuous gastropod larvæ. They are therefore of considerable economic importance in the sea.

Diet and food resources of marine-feeding otters (Lutra lutra, Mammalia) were studied along the coast of central Norway, where otters breed in all seasons. The fish and crab fauna in the 0–10 m depth zone where otters forage were sampled and otter spraints collected monthly for three years. Results were compared with published data from Shetland where otters breed mainly in summer. Most of the main prey species showed significant seasonal variation in numbers or biomass, which tended to be low in late winter or spring. The variations during the rest of the year were not synchronized between species. The combined density of the main prey species of Shetland otters, which peaked during summer, was low in Norway. This species group, eelpout (Zoarches viviparus), butterfish (Pholis gunnellus) and rocklings (Ciliata sp., Gaidropsarus sp. ), also constituted a smaller fraction of the total catch in Norway than in Shetland.) and bullrout (Myoxocephalus scorpius), constituted a larger fraction of the catch in Norway than in Shetland. Thus the otter's food resources on the Norwegian coast were seasonal, being minimal during the early months of the year, but with no clear maximum season as there is in Shetland. This may explain the differences in reproductive timing in the non-seasonal or autumn and winter species, cod (Gadus morhua.

In 1959 and 1960 eight surveys were made in an area about 54 x 83 km in the English Channel immediately south of Plymouth (Armstrong & Butler, 1962b). Measurements of temperature and salinity and of phosphate and silicate concentrations showed a good deal of variation from place to place so that it would be difficult to accept results from any one station as typical of the area. The density distributions suggested a general eastward movement in the winter and, in summer, a movement of surface water offshore from the English coast, with a corresponding onshore movement of deeper water.

Merluccius merluccius is an economically and ecologically important demersal species inhabiting the Atlantic Ocean and the Mediterranean Sea; however, reproductive knowledge about this species, along the North African coast is still missing. Monthly samples were collected from November 2010 to October 2011 along the North Tunisian coast. Morphometric parameters were measured, and histological preparations of gonadic tissues provided detailed information on the reproductive biology. Ovary maturity data showed a protracted spawning season throughout the year, with peaks in January, April and August. In females of M. merluccius, seasonal variability in weight and length were noticed, with higher values in the first part of the study period (November–April) than from May to October. Analysing separately these two periods, significant relationships were observed between gonadic maturation indices and the somatic and gonadic indices, suggesting a seasonal differential use of energy intake. From November to May the fish alternate the use of their energy for body growth and reserves for later uses (i.e fat, muscle and liver mass) or for gonadic growth. From June to October the energy is converted mainly into gonad weight and less to somatic growth. The maturity ogives obtained by macroscopic and histological maturity staging methods showed significant differences; however, in both cases the length at first maturity estimates were around 29 cm. Nonetheless, when selecting the main spawning period, the L50 estimation was heavily reduced to 24 cm, suggesting careful attention in the selection of the samples to be used specially for fishery management purposes.

The macrofauna of the benthic boundary layer (macrozooplankton and suprabenthos) was studied at six stations in May–June 1993 in the English Channel over sediments ranging from medium sand to pebble. The fauna collected consisted of 227 taxa in 30 suprabenthic sledge hauls. Numerically, the macrozooplankton was dominated by euphausids, chaetognaths, the holoplanktonic amphipod Apherusa spp. and fish larvae, and the suprabenthos by mysids (Anchialina agilis, Gastrosaccus spp.), amphipods (Stenothoe marina) and cumaceans at both medium sand stations. Suprabenthos species richness and diversity were significantly higher at western stations, in contrast to the pattern for macrozooplankton. The density of macrozooplankton was significantly higher, and suprabenthos significantly lower, at the western stations. The biomass of macrozooplankton was similar at the six stations, except in the middle of the Dover Strait which had a low biomass. The biomass of the suprabenthos was highest in the eastern part of the Channel. Two main assemblages were distinguished in relation to planktonic production and sediment composition: three western stations with two subgroups (stations 1 and 3 along the coasts of Brittany and station 2 off Plymouth); and the eastern stations also with two subgroups (station 4 in the Bay of Seine and stations 5 and 6 in the Dover Strait). For the macrozooplankton, two types of trophic structures could be distinguished: stations 1 and 4 where suspension-feeders dominated and the other stations (2, 3, 5 and 6) where carnivorous plankton feeders, omnivorous and scavengers predominate. For the suprabenthos, the plankton feeding, omnivorous and carnivorous trophic guilds dominated each station.

The small free-swimming scallops, Chlamys hastata and Chlamys rubida, are frequently encrusted by the sponges Mycale adhaerens and Myxilla incrustans. It is unclear why this association exists. We hypothesized that living on scallop valves increases sponge survival by reducing the effects of sediment accumulation. Scallops were collected to measure correlations between sediment load and encrusting sponge mass. In the laboratory, the survival of sponges on living scallops and empty scallop valves was measured. Time-lapse video was used to quantify spontaneous swimming and clapping of C. hastata. In the field, both scallop size and sponge mass were significantly greater in high turbidity sites. In the laboratory, sponges on empty scallop valves experienced near complete mortality after five weeks. Manually clearing sediments increased survival but did not duplicate the high survival of sponges on living scallops, which regularly swam or clapped their valves.

Libidoclaea granaria was collected as part of the by-catch of the Zygochlamys patagonica (Bivalvia: Pectinidae) fishery, between 36° and 39°40′S and at 80 to 128 m depth. Crab densities ranged from 0 to 150 individuals 100 m−2, with a mean of 9·8±20·4 individuals 100 m−2. Mature males and females ranged from 24 to 61 mm, and from 16 to 48 mm, carapace width (CW), respectively. The largest immature female measured 22·5 mm CW. The number of eggs carried by a female ranged from 1200 to 9300. Sponges were the most frequent epizoic organisms, followed by the lepadomorph cirriped Ornatoscalpellum gibberum, Serpulidae and Spirorbidae worms. Since all these organisms were reported on Z. patagonica beds, crabs are camouflaged to match their habitat. Small crabs usually had naked carapaces, indicating a high moult frequency. Larger crabs instead, had epibionts on their carapaces, suggesting a lesser moult frequency. The erosion of carapace spines and the heavy epibiosis of large specimens suggest the existence of a terminal anecdysis.

The eggs of Gobius minutus and Gobius microps are already known, Petersen (1892, 1917) having distinguished between them and figured them. Apparently the only mention of those of Gobius pictus is by Holt and Byrne (1901) who give the size of the eggs as about 0.80 mm. high by 0.65 mm. broad. Gobius minutus and pictus often occur together in the Sound and at the mouth of the Cattewater, but pictus is chiefly to be found near coarse sandy bottoms such as one gets near Duke Rock and New Grounds. Gobius microps occurs usually higher up the rivers, but the eggs and young are to be found occasionally in the Sound in the same localities as minutus and pictus.

Shells with eggs on them are commonly dredged in the Sound, those between Plymouth and the Breakwater are usually minutus, but pictus eggs are dredged from New Grounds and microps sometimes in the Catte-water.

In order to distinguish the eggs of these three species, and especially to obtain the eggs of G. pictus, adults of all three species were isolated in separate tanks with shells on the bottom on which the fish laid their eggs. The adults of minutus were from the Cattewater, those of pictus from New Grounds, and microps from Chelson Meadow, which opens into the Laira and where the water varies much in salinity, from almost fresh to ordinary sea-water strength. G. minutus and pictus were put into the tanks into ordinary running sea-water, straight from the vessel in which they were brought in from the dredge.

The thin-walled setae on the outer rami of the antennules of decapod Crustacea are considered to be chemoreceptors. It is not known whether stimulatory molecules enter each seta through the cuticular wall or via an apical pore. In this paper evidence is presented that the antennular chemoreceptors of the brown shrimp, Crangon crangon (L.), bear apical pores. In some field and laboratory populations, however, the pores are blocked by an epizooic, blue-green alga and this provides a direct means of testing the hypothesis that the apical pore is important in the sensory process.

1. Details are given of the results of a series of hauls with the 2-metre stramin ring-trawl fished at six different depths in daylight, at dusk, in the dark, at dawn and again in daylight on June 3rd–4th, 1926.

2. A comparison is given of the results obtained on the four nights July 15–16th, 1924; June 17–18–19th, 1925, and June 3rd–4th, 1926.

3. The importance is stressed of the effects on the type of behaviour shown by any animal produced by the depth at which it is living in the daylight and the speed at which it can swim upwards.

Spatial distribution patterns of two small serranids, Serranus scriba and S. cabrilla, have been investigated in  June 2001 in north-eastern Sardinia (Tyrrhenian Sea, Italy). Density and size of both species were estimated by visual census on shallow (5–7 m) rocky reefs constituted by different mineralogical types (granites vs carbonates), at different locations (several kilometres apart from each other) and sites (hundreds of metres from each other). Serranus scriba was significantly more abundant on granite rocks (where it also showed a greater frequency of large specimens) than on carbonates, while S. cabrilla displayed opposite patterns.