This article reports on a new species originating from the northern Chilean fjord region, which argued for the resurrection of Cornulotrocha, here classified as a new subgenus of Clathria, for sponges with choanosomal acanthostyles, ectosomal quasidiactinal monactines and rosettes of palmate (an)isochelae. Clathria (Cornulotrocha) rosetafiordica sp. nov. was collected at 23 m depth at Quintupeu fjord (∼42°S), and is unique within this very large genus, in possessing rosettes of palmate anisochelae. The new species is compared to the only other known Clathria (Cornulotrocha), viz. C. (Cornulotrocha) cheliradians n. comb.; to the single other Clathria known with anisochelae, viz C. (Thalysias) dubia; to other crustose Clathria from southern South America, the subantarctic and Antarctic areas; and also to other sponges bearing rosettes; and is considered clearly distinct from all. The phylogenetic significance of rosettes is discussed, a likely adaptive value being discarded in view of the variable location of such structures in the distinct poecilosclerid taxa in which they occur.

In the course of a study of the British Nuculidae the specific characters of a large number of specimens of N. turgida and N. moorei were re-examined. It was found that no distinction could be made between the two.

Examination of variation in shell colour showed that it was not possible to differentiate into two distinct types. There was a continuous graded seiies from a dark purple-grey in which the basic yellow colour was almost completely masked, through a series with decreasing numbers of purple-grey radiations, to shells in which the markings could not be differentiated as rays, and finally to shells without purple coloration. The purple-grey colour is not necessarily laid down continuously, and it does not develop until the end of the second year. As the shells get older an increasing percentage of them become coloured.

Although the two types of faecal pellets described by Moore were found they could not be associated with the radiate and non-radiate shell types. The five grooved faeces that he claimed were typical of the radiate variety, were found in only three of the fifty-six specimens examined. Only one of them was from a definitely radiate shell.

Shell measurements and growth rates were studied, and no feature was found on which two forms could be separated. Samples show that reproduction takes place at the same time in the rayed and unrayed shells.

As the name N. nitida Sowerby is preoccupied it is suggested that the name N. turgida Marshall should now be used with N. moorei a synonym of it.

Three new species of paramunnid isopods are described: Pentaceration pleonarietis sp. nov., Neasellus argentinensis sp. nov. and N. bicarinatus sp. nov. The three species were collected off Buenos Aires province, the last one was also collected off Chubut province, Argentine Sea. The species belonging to Pentaceration represents the first record of this genus in the Argentine Sea. The diagnostic characters of the genus Neasellus are revised and besides the inclusion of the two new species herein described, a new combination for the species Pelagogonium oculatum Schultz, 1977 is proposed.

During the summer of 1936 I obtained mature specimens of the medusa of Corymorpha nutans at Plymouth. An account of the early development of the hydroid reared from the fertilized eggs of these is given below. Young polyps of this species have been figured by Allman (1871) and by Hartlaub (1907). Allman found his young polyps developing apparently from the rooting filaments of the parent hydroid which had become free. Hartlaub figures and assigns young polyps which he found in the plankton at Helgoland to this species.

The absence of systematic records showing the variations of the floating fauna and flora, or plankton, of the Plymouth waters is much to be regretted. My observations on the amount of animal and plant life suspended in the sea from the surface to the bottom would show that in comparison with similar observations made elsewhere, the quantity of plankton in this locality was during the past summer surprisingly small. The absence of data upon which comparisons could be based between the state of the water in this season and that obtaining in former years is all the more to be deplored because the present season has in many respects been a remarkable one. In the first place, the Plymouth mackerel fishery has so far been a complete failure; it has further been found that dog-fishes (both Scyllium and Acanthias) were not obtainable during June and July; and lastly, Aurelia aurita, which in summer is usually common, was extremely scarce in the Sound and tidal waters of Plymouth. If my Burmise that the amount of plankton was for the locality exceptionally small proves correct, then these three salient instances of scarcity of animals which are directly or indirectly dependent on the plankton for their food will suffice to show the importance of a series of more or less continuous observations on the physical and biological condition of the inshore and Channel waters. Were accurate information on these points available, it would in all probability enable us to explain, and we might even in time be able to foresee, the occurrence of so important an event as the exceptionally sporadic appearance of the mackerel in 1892.

A large (100 km) rocky coast intertidal was sampled several times (from 2004 to 2006) to assess the affection degree of invertebrate assemblages impacted by a continuous oil spill. Twelve locations and two intertidal heights were selected along the coast representing two spatial scales (kilometres and tens of metres). Univariate and multivariate analyses of variance were used to test whether faunal assemblages exposed to different intensities of oil disturbance differ in terms of diversity, total cover, key species cover and trophic guilds. Whereas no significant differences in midshore assemblages were noted, the low intertidal zone exhibited comparatively lower abundance values of the limpet Patella ulyssiponensis at worst affected sites. Besides, a generalized increasing diversity trend was found in the low intertidal from 2004 to 2006. Natural variability of communities is also discussed as the cause of the differences we observed. With respect to spatial and temporal scales of variation, mid- intertidal communities showed a more consistent structure, while lowshore assemblages were markedly heterogeneous in practically all the variables measured.

A Synopsis of the Aphroditidre of the English Channel by Mr. T. V. Hodgson is given in the Journal Marine Biological Association, Vol. VI, No. 2, 1900.

APhrodita aculeata, Lin. McIntosh, Mon. Brit. Ann., Vol. II, p. 247.

During the last four years collections of plankton from deep water have been made regularly on the cruises of R.V. ‘Sarsia’. The opportunity has been taken to study the biology of the scyphomedusa Atolla wyvillei. It was hoped that with material collected from the same area at different times of the year it might be possible to gain some information on the growth and length of life of this medusa. The collections have been supplemented by a number of specimens taken on recent cruises of R.R.S. ‘Discovery II’, and a total of nearly 300 medusae have been examined. The collections were made with the 2 m stramin ring trawl and the Isaacs-Kidd pelagic trawl mostly from the Bay of Biscay.

The sperm whale, Physeter macrocephalus, was the most captured great whale in the Azores Archipelago by land-based whaling and nowadays is the most appealing species for whale watching, one of the archipelago's principal sources of tourism. Our objective was to compare number of sightings during whaling and whale watching activities. Our main question to address the possible impact of past whaling in recent whale watching is: does a present-day eco-tourist sight more or fewer sperm whales than a whaler could sight in the past? For that, a compilation of data resulting both from past whaling records and recent whale watching records was conducted. We obtained a total of 727 independent sightings of sperm whales during a total of 280 different days of sperm whaling between 1947 and 1973. A total of 1767 sperm whale sightings were made during 1133 days of whale watching activities, between 1997 and 2008. The sperm whale sighting per unit of effort average was significantly higher in the past (35.68) than in the present (12.06). In the Azores, captures over the decades greatly decreased the number of sperm whales in the region and twenty years after the end of sperm whaling a reduced number of recent sightings were found.

When red blood cells are subjected to mechanical stresses, they change shape with very little resistance. Such deformability of erythrocytes plays a crucial role in their function and survival in the circulation since they must undergo large deformation whenever they pass through narrow capillary vessels. While this mechanical characteristic of erythrocytes has been attributed to their unique cellular structure, it has also been shown that considerable alterations in this property result from changes in cellular metabolism and in surrounding plasma physicochemistry (Weed, LaCelle & Merrill, 1969; Kikuchi & Koyama, 1984a, b). It might be supposed, therefore that red blood cell deformability would be modified, when animals are exposed to different environmental conditions, with significant effects on their acclimatization or survival under the varied conditions. However, little is known of this aspect of fish cardiovascular physiology.

Popularly known as blue land crab, Cardisoma guanhumi is heavily exploited as food and considered as an important economic resource in Brazil. In recent decades, the species has experienced a sharp population decline by the loss and/or degradation of its natural habitat and overfishing. The present study aimed to investigate the genetic variation and connectivity among 154 specimens of C. guanhumi sampled along the coast of Pernambuco in five different levels of tropical mangroves conservation. Nine ISSR primers were used for assessing the genetic variation of the species. The genetic diversity observed in C. guanhumi was high reinforcing the condition of a resilient species, indicating a good conservation status of this resource in Pernambuco. The hypothesis of panmixia was rejected in favour of a heterogeneous distribution of the genotypes of C. guanhumi (ФST = 0.19) despite the high gene flow observed in the study region. Such difference could be attributed to the candidate loci being under positive selection and differentially distributed between the geographic regions assessed. The genetic structure showed a pattern of fine-scale genetic structuring better fitted to a model of selection-mediated geographic cline. Cluster analysis and candidate loci under positive selection suggested that the populations of C. guanhumi in the North-central and South coasts of Pernambuco might be different management units and must be managed independently. In conclusion, exhaustion of natural stocks upon which fishing is totally dependent will lead to serious ecological and sociocultural impacts.

Carpet shell clam populations on the Tunisian coastline are susceptible to several microbial pathogen challenges. In this study we report the results of five years' surveillance, conducted from January 2004 till June 2009, for detection of Perkinsosis and brown ring disease (BRD). The survey covered three sites of natural populations of Ruditapes decussatus in a Tunisian lagoon, the North Lake of Tunis. Perkinsosis was detected preferentially in winter periods from the external and marine site, BRD was detected more frequently in the summer periods in a more proximal collection site (in the lake) and was positively correlated with concentrations of heterotrophic Vibrio sp. Our results suggest that several factors other than temperature and salinity might explain spatial distribution variability and natural intensities for these infections in carpet shell clam populations.

Crab species had not been exploited until recently in the San Matías Gulf. An experimental trap fishery plan was developed to provide information on the feasibility of their potential extraction. Sampling was carried out using an artisanal shellfish boat in the San Matías Gulf. Nine baited traps, three of each type (cubical, tubular-conical and tubular-pyramidal) were intercalated along a master line. The total number of crabs of each species caught was compared among lines (N=27), types of trap and soaking times (6, 24 and 48 h). A total of 137 traps of 243 traps employed caught crabs. More crabs were caught in the cubical traps than in the other types. Comparisons of numbers of crabs among lines allowed identification of areas having different relative abundances, with an average of 3.56 crabs per trap. The catch of Ovalipes trimaculatus was significantly greater in lines on the 10-m isobath. Two lines, on the 50-m isobath, showed the best results for Platyxanthus patagonicus. The total number of crabs per trap obtained during a soaking time of 6 h was significantly less than the number caught with longer soaking times. Only individuals exceeding 50 mm in carapace width were caught. The size-frequency distributions differed significantly between sexes for the two species, with males larger than females. In O. trimaculatus, males made up 29% of the catch and the remainder was constituted of non-ovigerous females; mean carapace width was 92.93 mm for females and 105.93 mm for males. Forty per cent of P. patagonicus were males (mean carapace width: 99.33 mm). Females bearing eggs amounted to 45% of the total females. Females' mean carapace width was 90.58 mm. Based on the results obtained, preliminary suggestions for management of a potential fishery for these species are made within a precautionary approach.

A new species of the cold-temperate austral amphipod genus Carangolia (Gammaridea: Urothoidae) is described from bathyal depths of the Bay of Biscay (north-east Atlantic). It was occasionally sampled in the south-eastern part of the Bay with sledges towed over muddy bottoms between 522 and 924 m water depth. This depth range falls mainly below the mud-line where the proportion of organic carbon increases in response to the deposition of silts and/or clay sediment. Most specimens were sampled by the lower net of the sledges, indicating a close association with the bottom. Abundance was relatively low, ranging between 0·18 and 4·90 ind 100 m−2, latter recorded below 700 m depth. The unusual massive appearance of Carangolia mandibles and its preference for bathyal foraminiferal oozes suggest that it is a specialized foraminifer consumer. The antitropical distribution pattern currently displayed by the genus could be an artefact due to equatorial submergence.

The sea urchin Diadema africanum is considered a key herbivore in sublittoral ecosystems of the Canary Islands. Spatial and temporal variability in population structure was carried out at Gran Canaria. We performed a morphometric and population density analysis during 2005, 2006 and 2007 at four sites in zones of Gran Canaria. The study considered a vertical gradient (5, 10 and 20 m depth) during both seasons, the cold season (February and March) and the warm season (October and November). The sea urchin D. africanum in Gran Canaria exhibited an overall density of 7.59 ± 2.92 urchin m−2. A two-way ANOVA evidenced spatial differences in mean abundance of the species, while seasonality was not relevant. The vertical analysis of the abundance of D. africanum showed differences, the smaller sizes appeared at greater depths. The Aristotle's lantern width decreased in a vertical gradient, being remarkable between 10 and 20 m. Findings of uniformity in size over time, a stable range of high densities and the lack of a relationship between the size of the sea urchins and the season reveals that the density–size strategy displayed by D. africanum which explains in turns the high stability of the urchin barrens, which, once developed, remain as areas of permanent desertification in subtidal depths throughout the Canary Archipelago.

In a former paper (1922) it was shown that the pH value of stored sea water decreased owing to the production of carbonic acid by organisms in it, and the oxidisable matter as indicated by this biological method appeared to be higher than the result obtained by oxidation with permanganate, according to various analyses available for comparison. These, however, were not done on the same water, so an attempt was made to determine this quantity on water of the English Channel off Plymouth. As is well known the permanganate method gives results which vary appreciably, according to the conditions of the experiment.

The bluefish, Pomatomus saltatrix, is quite abundant in the Gulf of Gabes, off the south-eastern coast of Tunisia. It is commercially exploited by artisanal gears and trawlers all year round, and by purse seine nets from May to August (bluefish fishery season). Catches of bluefish, in the period 1996–2004 fluctuated between 365.6 t and 1240.1 t with an annual average of 805 t. This fluctuation, partially due to the migratory nature of the species, could be also attributed to the fleet activities that sometimes changed at the mercy of the operators. The analysis of the virtual population of bluefish in the Gulf of Gabes showed that, in 2002, the stock that had just recovered rightly after an excessive fishing in 1996–1997 was again subject to a fishing effort that passed its capacity (E=0.71; E>0.5). The biomass (B) estimated to be ~2178.9 t only tolerated the extraction of 713.4 t (more or less one-third of B). However, the three fleets in use removed 1029.1 t with a yield per recruit (Y/R) of 70.5 g. As a result of this over-fishing, the actual stock of bluefish in the Gulf of Gabes was characterized by individuals having a mean total length of 17.88 cm, a size which is much lower than the one at first sexual maturity (23.5 cm). The turnover (D/B) being of 75.23%, it did not allow the reconstitution of the stock. The total removals (~1639 t) due to both natural mortality (M=0.28) and fishing mortality (F=0.675) had to be compensated especially by individual growth (1534.2 t; 93.6%) because of the low weight of the recruits.

The shrimp Hippolyte sapphica has a unique and sharp rostral dimorphism: morphotype A with a well-developed dentate rostrum, and morphotype B with a short, juvenile-like toothless rostrum. Previous research has shown that both morphotypes/forms belong to the same species and co-occur in the same habitat. Both forms occur in both sexes; however, form B individuals have a higher tendency to become males. Moreover, form A females are characterized by prolonged viability. The present comparative morphometric study concentrates on the changes induced by the rostral dimorphism and interprets them in terms of eco-morphological adaptations. Results showed that (i) the rostral length was the most isometric among the studied morphometric variables; (ii) males of A and B forms were not significantly different morphometrically; (iii) unexpectedly, form A non-ovigerous females had more developed carapace, abdominal somites and appendages in comparison with form B and, finally (iv), form B ovigerous females had higher tail and scaphocerite lengths, suggesting that they overcome higher turbulent force during the rapid backward movements and that the long rostrum improves hydrodynamic streamlining and stability. In conclusion, the previous finding that form B individuals tend to become males receives an adaptational explanation. The gene(s) responsible for the short rostrum accumulate in males, where their micro-evolutionary disadvantage is minimal or even absent.

Reproductive aspects of the sea cucumber Athyonidium chilensis were studied over a year in Valdivia, Chile, through gonad index (GI) analysis, macro- and microscopic analysis of the gonads, fecundity and size at first sexual maturity estimations. We also explored the reliability of live size estimators for their use in fisheries. Athyonidium chilensis showed continuous gametogenesis and spawning individuals could be found throughout the year. However, spring was the main reproductive time, where an important GI decrease coincided with enhanced spawning activity evidenced through histology. GIs recovered in summer, and new signs of enhanced spawning activity were observed towards autumn (April 2008). GI peaks were observed in August 2007 and March 2008 for females (22.8 and 24.4% respectively) and September 2007 and March 2008 for males (31.9 and 25.9% respectively). Low mean GIs occurred in May and December 2007 for females (15.2 and 11.6% respectively) and May and October 2007 for males (12.7 and 14.1% respectively). Males reached sexual maturity at a smaller size than females (males: 21.2 g, females: 43.7 g eviscerated weight), and mature females showed a high mean absolute fecundity for a species with lecithotrophic larval development (6.31 × 105 ± 1.97 × 105 SD). For fisheries, we recommend a minimum catch size over 237.89 g drained weight to ensure that caught individuals are sexually mature. This study provides relevant information for the conservation and fishery management of A. chilensis. Continuous gametogenesis and high fecundity make this species particularly suitable for aquaculture in southern Chile.