Anyone who has examined the so-called “protective” spines of the various Zoæa larvæ must have been struck by their great tendency to develop in one straight line, parallel to the long axis of the body. Among the Macrura this is the case in the Zooæ of Peneus, in the larva attributed by Claus to Hippolyte, and in the Galatheidé. In the Brachyura the same result is attained in a slightly different way.

The sponge genus Strongylodesma is reviewed and redefined, and now accommodates eight closely related species. The type species of Strongylodesma Lévi is redescribed and an additional two new species are described from the Indo-Pacific: S. novaecaledoniae sp. nov. and S. tongaensis sp. nov. Several specimens previously identified as species of Batzella (Poecilosclerida: Chondropsidae) have been re-assigned to Strongylodesma, as the new species S. purpureus sp. nov. and S. nigra sp. nov. With the description here of new species from the Pacific Ocean and Caribbean Atlantic, the biogeographical distribution of Strongylodesma now appears to be generally tropical with a subtropical South African component, whereas previously it was only known from South Africa. Although species of Strongylodesma have not previously been recorded from the intermediate locations (Western Indian Ocean, South-east Asia, central west Pacific, and New Zealand), re-evaluation here will facilitate more readily the recognition of taxa in these intermediate regions, if they exist, in the future. The species are not widespread, except perhaps along the south-east coast of South Africa, and where they occur they are not abundant. Species occur over a wide depth range, from the intertidal in Tsitsikamma, South Africa, to 140 m in the Caribbean.

The numbers of fish eggs and planktonic stages of fish taken during a 5-year period by the Scottish research vessels in the northern North Sea have been associated with the presence of Sagitta elegans and S. setosa in the same collections and over an 11-year period with the presence or absence of S. elegans. The results confirm Russell's findings in the English Channel that fish larvae are more abundant when S. elegans is present than when S. setosa is present.

The total numbers of fish eggs do not show these differences; spawning does not appear to be any more productive in water associated with S. elegans, rather the reverse, and this is shown to be so for the eggs of those species separately examined. Numbers of the larvae were distinctly greater in the ‘mixed’ conditions indicated by the presence of S. elegans and a more abundant food supply is a possible cause. That the differences may signify a more fundamental effect, however, is suggested by the figures for cod and haddock eggs, which show the earliest stages to be more abundant where S. elegans was absent although later stages were more abundant when S. elegans was present.

The aim of this study was to analyse the genetic diversity and population structure in the razor clam Ensis siliqua along the European Atlantic coast taking into account their recent history of exploitation and the ‘Prestige' oil spill. To this end we examined the genetic variability of microsatellite markers in 211 razor clams from five populations in Ireland, Portugal and Spain. Microsatellite data revealed a low genetic differentiation between the Spanish and Portuguese populations (FST = 0–0.032) and a moderate differentiation of these populations and the Irish samples (FST = 0.071–0.100). Although we observed changes in genetic diversity in accordance with the level of exploitation and the distribution of the oil spill, these changes were mild and not significant after Bonferroni correction. This could be the result of a genuine low impact, lack of statistical power and/or the capacity of this species to recolonize quickly after the impact of anthropogenic stressors. Supporting the latter argument we found a significant temporal heterogeneity of allelic frequencies in samples coming from the same sampling locality that could be attributed to the movement of adults or larvae from unaffected source populations.

Age and growth of the snipefish was studied based on samples collected in the Portuguese continental waters between 1996 and 1998. Analysis was conducted for two species, Macrorhamphosus scolopax and M. gracilis and for both species combined. Total length ranged from 5.5 to 18.2 cm for M. scolopax and from 5.4 to 17.3 cm for M. gracilis. Length–weight relationships were described for M. scolopax (a=0.00401; b=3.127), M. gracilis (a=0.00459; b=3.006) and both combined (a=0.00240; b=3.282). Age estimation, based on otolith observations, resulted in six and five years maximum age attributed to M. scolopax and M. gracilis, respectively. Back-calculation analysis based on a polynomial relation of the otolith radius on total length provided significantly smaller lengths-at-age compared with observed lengths. The von Bertalanffy growth curves fitted to observed lengths-at-age provided parameters of L∞=15.7 cm, K=0.654, t0=−1.066 for M. scolopax; L∞=14.2 cm, K=0.694, t0=−0.954 for M. gracilis and L∞=15.8 cm, K=0.470, t0=−1.408 for both species combined.

Some of the limits to the use of serology to identify prey species in the digestive tracts of cephalopods have been evaluated. Cuttlefish, Sepia officinalis, were given meals of krill slurry (Euphausia superba). Protein extracts of contents from four regions of the digestive tract, stomach, caecum, digestive gland and intestine, were tested for prey antigenicity. Digestion times (loss of antigenicity) ranged from 1 to 8 h depending on sampling site. Stomach and caecum emptied rapidly, but meal antigenicity persisted longer in the digestive gland. The Sepia experiments provide a basis for interpretation of results from natural predation by cephalopods).

Specimens of Opisthoteuthis grimaldii were video recorded in a shipboard aquarium and their behavioural traits, such as bottom resting, flat-spreading, web-inversion and ballooning response, were described. Ballooning, as defence response, has been recorded only for cirrate octopod families with an intermediate web (Cirroteuthidae: Stauroteuthidae), and this structure has been supposed to be essential for developing this behaviour. Members of the Opisthoteuthidae family lack an intermediate web, indicating that this is a common defence response in cirrates, expressed in a basic form in the Opisthoteuthidae, offering an illustration of how this behaviour can evolve.

In this study, polyploidy level was determined by flow cytometry analysis. The effect of polyploidy by colchicine treatment was examined on the growth parameters, malondealdehyde (MDA), as well as activities of antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) in response to different levels of salinity in Dunaliella salina. The results of algal growth indicated that 3 M NaCl was the optimal concentration of salt, since the highest enhancement in fresh and dry weight, chlorophyll and carotenoids, soluble sugar, glycerol, protein and starch content was observed in comparison to other concentrations. The amount of these metabolites declined in the concentrations under optimum salinity. The least and highest amounts of MDA were observed at 1 and 4 M NaCl respectively. Polyploidy in optimum concentration of salt, caused further increment of the above growth parameters. In relation to this, in most cases, treatment of 0.1% colchicine was most effective. The beneficial effects of polyploidy in non-optimal conditions were also found in some parameters such as biomass, chlorophyll, carotenoids, proteins and starch. Furthermore, the activity of antioxidant enzymes CAT, SOD and POD showed a positive significant correlation with salt stress and these were maximized at 4 M NaCl. Polyploidy (especially colchicine 0.1%) affected activity of these antioxidant enzymes in some concentrations of salt. Overall, our results suggest that the microalgae has significantly different responses to salt stress based on ploidy levels.

(1) The tidal cycle and that of solar elevation interact to produce patterns in seabed irradiance during the day which change over the springs-neaps cycle. In locations where high water springs is at midday, there is a single peak in seabed irradiance in the middle of the day at neap tides and two peaks in seabed irradiance (one in the morning, the other in the evening) at spring tides.

(2) These cycles also interact to produce a springs–neaps cycle of daily mean irradiance, which is relevant to the growth of benthic algae. The pattern of this cycle will also vary from place to place. In locations where low water springs is in the middle of the day the pattern is straightforward: maximum daily irradiance always occurs at spring tides. However, where high water springs is in the middle of the day, the cycle can reverse as the days get longer. The timing of the switch in the cycle depends upon the water clarity.

(3) Variations in attenuation over the springs–neaps cycle will also be important. In the Menai Strait, a springs–neaps cycle in K is often (but not always) observed, higher attenuations occurring at spring tides when seabed sediments are stirred up by the stronger tidal currents. This will reduce seabed irradiance at spring tides and tend to favour greater irradiance at neaps. In our model runs, K was kept constant because at present it is difficult to predict these changes. However, in our observations there is evidence of greater seabed irradiance at neap tides associated with greater water clarity. Variations in cloud cover during the day can also affect the regular cycles predicted by the model.

The authors are grateful to Professor Ernest Naylor for encouragement and for information on animal behaviour and light. Members of the Marine Optics Group at Menai Bridge helped with the sampling during the experimental work in July 1994.

Edwardsiidae is one of the most speciose families within order Actiniaria with ~75 valid species of burrowing sea anemones. Five edwardsiids have been recorded in South Atlantic waters with only two species known for Brazil: Nematostella vectensis and Edwardsia migottoi. Such low diversity is probably the result of a historical small number of specialists in the region combined with difficulties in collecting and identifying these small burrowing animals. Although edwardsiids have been reported from Brazil since at least the 1960s, these reports did not include proper descriptions or specific identification, making comparison to other valid species impossible. Here we describe a new genus, Isoscolanthus gen. nov., and two new species: Isoscolanthus iemanjae sp. nov., Isoscolanthus janainae sp. nov. and we also describe Scolanthus crypticus sp. nov., the first species of the genus for Brazil. Isoscolanthus gen. nov. is easily distinguished from other edwardsiid genera by a combination of external (i.e. presence of periderm and nemathybomes in proximal end and 12 tentacles), microanatomical (i.e. four microcnemes) and cnidom features (i.e. pterotrichs in nemathybomes). In addition to the description of the new genus and species, we expand the range distribution of Nematostella vectensis and Edwardsia migottoi in the South-western Atlantic. The number of edwardsiids known from Brazil is raised from two to five species, substantially increasing the diversity of soft-bottom sea anemones for South Atlantic waters.

A massive toxic bloom ofChrysochromulina polylepis occurred along the Swedish west coast in May and June 1988 with severe effects on most biota in shallow marine habitats. In the present study, the effects on the common dog-whelk,Nucella lapillus was investigated in the archipelago at the mouth of the Gullmar Fjord.

Mortality varied throughout the archipelago, with extinction of populations in the inner parts and survivors found only on the outermost islands. Even on these sites, mortality could be as high as 98­99%. Extensive samples of survivors and dead animals were divided into five age groups dependent on size and wear of the shell. The cohort consisting of 3­4 year old individuals suffered the lowest mortality, while mortality was almost total in younger and older cohorts. In each age group, except the oldest, survivors were significantly larger than the dead.

The number of egg capsules laid per female in 1988 seemed normal, but about half of the capsules were empty. The number of young per capsule was significantly lower in 1988 compared to 1989, but the young were significantly bigger.

Wood-boring bivalves (Bivalvia, family Teredinidae), also known as shipworms, host dinitrogen-fixing and cellulolytic symbiotic bacteria in gill bacteriocytes, which may be a necessary adaptation to a wooden diet. Although oxygen (O2) inhibits nitrogenase in other species, symbionts are able to fix nitrogen (N) within the gill tissue and provide newly fixed N to the host shipworm. The recent direct evidence of new N incorporation into the host tissue indicates that there are potentially complex nutrient cycles in this symbiosis and uninvestigated controls upon these cycles.To elucidate the mechanisms of this unique N2-fixing symbiosis and determine whether symbionts can excrete newly fixed N, we measured rates of growth, N2-fixation, respiration, and inorganic N content for the cultivated symbiont Teredinibacter turnerae (γ-proteobacteria, strain T7901) under a range of headspace O2 conditions. In all conditions, headspace O2 did not affect maximum specific N2-fixation and respiration activity, but did influence the rate and timing of growth. These results are consistent with the development of microaerobic conditions through an oxygen gradient in the culture medium, which facilitates N2-fixation and growth. The medium accumulated a small amount of NH4+, which represented 0.5–2.5% of the total N fixed by the culture. We constructed a simple N budget for T. turnerae to assess the role of the major known N sources and sinks. The N budget was not closed, indicating that new N is allocated to currently unidentified sinks, which may include excreted dissolved organic nitrogen.

There are few records in the literature of the relative proportions of the sexes in natural populations of echinoderms, and the samples studied have mostly been small. Selenka (1867) has stated that in Holothurians in general males are rarer than females, and Becher (1907) found that males were very rare in Rhabdomolgus ruber. Koehler (1907) noted that in the ophiuroidOphiacantha vivipara there were more females than males.

An organism's maximum gonad investment (MGI) typically indicates its reproductive season and is often measured by the peak of the gonadosomatic index. Since external sexual dimorphism is often not evident, intrinsic sex differences remain unstudied. We analysed the reproductive seasonality of each sex of the broadcast-spawning sea cucumber Holothuria (Halodeima) inornata in two populations (Caleta de Campos, Michoacán ‘CC’ and Puerto Madero, Chiapas ‘PM’) in the southern coast of the Mexican Pacific by examining: intensity and duration of MGI, frequency of each gonadal developmental stage (GDS) through time, sexual asymmetry in GSI, sexual asymmetry in GDS, and adult sex ratio. We observed a trade-off between the intensity (%) and duration (months) of each sex's MGI: as intensity decreases, duration increases and conversely. The frequency of ripe and spawning stages was consistently higher in females than males. Sexual asymmetry in GSI was slightly female-biased in the PM population, but male-biased in the CC population. Sexual asymmetry in GDS showed a more recurrent sexual equality at PM than at CC. The adult sex ratio of each population did not differ significantly from unity, but showed a near-significant trend for male bias in the CC. Although H. inornata exhibited different MGI responses between males and females and more markedly in CC than in PM, it also showed a synchronized relation between its mass investment (GSI) and physiological investment (GDS), possibly reflecting an optimum reproductive strategy. Lastly, changes in GSI were not underpinned by changes in local temperature, but rather by regional temperature.

A second species of angler-fish, Lophius budegassa Spinola, 1807, is reported from British waters. This species has hitherto been reported only as far north as the Bay of Biscay. This is not thought to be an active extension of the range of this fish but to be due rather to failure to identify it, for specimens (misidentified as L. piscatorius) dating from the last century have been found in the British Museum (Natural History) collection.

The distinctive characters of both species are given.

Patterns of genetic and morphological variation among eight populations of Patella barbara along the coast of South Africa were examined to see whether reported differences in shell morphology and behaviour between the west and east coasts were mirrored by other morphological and/or genetic differences. Morphological analyses of radular structure, gut-loop coiling and sperm microstructure revealed no differences between the populations. Discriminant functions analysis based on shell morphometrics showed major overlap between populations and failed to separate them. Electrophoretic analysis of 17 enzyme loci gave an overall genetic identity (Nei) value of 0.995, a value which lies within the generally accepted range for conspecific populations. In two of the populations, at Dwesa and Arniston, individuals were found to be ‘gardening’ algal resources. At Clovelly, a ‘normal’ form of P. barbara was found on the rocks, whereas a reduced and tall-shelled form occurred on the ascidian Pyura stolonifera, demonstrating phenotypic morphological plasticity. It was concluded that different populations of Patella barbara are both morphologically indistinguishable and genetically homogenous along the coast of South Africa, thus providing good evidence for widespread gene flow.

Intracellular granules have been isolated from the digestive gland of the shore crab Carcinus maenas (L.). These granules are normally shed from this tissue during the digestive cycle and are shown to occur in considerable numbers in the faecal strands. The granules are amorphous to x-ray diffraction and remain in this state in sea-water for several weeks, although they will transform into crystalline apatite in simpler saline solutions. The fate of these deposits in the marine environment is discussed in relation to their contribution to sediments and phosphorites.

Enoplometopus callistus is reported for the first time from the Cape Verde Islands. In January 2001 two specimens were captured in depths of 100–150  m as by-catch in the lobster fisheries. One of them was dissected and kept in alcohol for future reference, the second one was put into an aquarium. The existing data on the distributions of the two Atlantic species of this genus, E. antillensis and E. callistus, indicate that the latter is restricted to the waters of the East Atlantic.

To date, the oedicerotid amphipod Monoculodes gibbosus Chevreux, 1888 is known in British seas from only two individuals collected from Loch Fyne and lodged in the Robertson Collection at Millport (Moore, 1984). Recent intensive research on other species in this family in the Clyde Sea area by one of us (D.J.B.) has resulted in the sporadic capture of further individuals of M. gibbosus (128 individuals in total) from Inchmarnock Water, southern Loch Fyne. This material allows us to expand our knowledge of the species' morphology, live colour, population structure, fecundity, egg size, breeding season, diet and behaviour. Notes on these topics are presented below.

In ecological studies of benthonic organisms it is advisable to sample the water immediately above the sediment-water interface rather than centimetres or metres above the bottom. The standard oceanographic water samplers cannot be relied upon to sample at the required level so a new instrument was designed. The instrument here described is a strengthened and simplified version of that described for use in shallow waters (up to 4 m) by Murray (1963). It has been successfully used in waters of up to 60 m deep but should withstand depths of up to 180 m.