The composition and spatial distribution of the mollusc fauna on the subtidal soft bottoms of the Ría de Aldán (Galicia, north-western Spain) were studied by means of quantitative sampling and multivariate analyses. The faunal distribution was mainly conditioned by a sedimentary gradient that was defined by a decreasing grain size from the mouth towards the inner margins of the ría. Several assemblages were determined which could be defined according to the classic terms of ‘community’ and ‘facies’. A ‘Venus fasciata community’ and a ‘facies of Goodallia triangularis–Pisione parapari’ are present in coarser sandy sediments of the outer ría area. The communities characterized by ‘Venus gallina’ and ‘Tellina fabula–Tellina tenuis’ were found in the fine sand bottoms at the centre and margins of the ría. The shallower and muddier sediments in the inner ría showed a mix of typical species from the ‘Abra alba’ and the ‘Venus gallina’ communities, and in the Río Aldán's mouth could be distinguished a facies of a protected zone.

A first record of the genus Aciculites in the Mediterranean Sea and the description of Aciculites mediterranea sp. nov. are here presented from a faunistic survey in a dark shallow marine cave of the north-western Sardinian karstic area. The new species is characterized by a massive cerebellum-like growth form, and a peculiar distribution of inhalant and exhalant areas, respectively, in depressed and elevated portions of the sponge surface. Oscules show a long narrow atrial cavity. Ectosomal skeleton is made of tangential anisostrongyles on elevated areas, and more or less vertical tufts of anisostrongyles in depressed inhalant areas. Anisostrongyles are smooth or with tips ornated by irregular tubercles. Sigmaspire microscleres are lacking. Choanosomal skeleton with tubercled irregular rizhoclone desmas and few scattered and variably oriented anisostrongyles. A comparative analysis of Aciculites mediterranea sp. nov. versus morphological diagnostic traits, geographical range and habitat of the species hitherto ascribed to Aciculites confirms that the peculiar distribution of the genus supports its relic condition of an ancient Tethyan fauna in the Mediterranean Sea.

The mortalities and subsequent recolonization of a rocky shore in S.W. Ireland following a bloom of the toxic dinoflagellate, Gyrodinium aureolum in 1979 are described. Selective mortalities of key animal species notably grazing gastropods were followed by a marked increase in fucoid algae. Enteromorpha spp. blooms were a feature of vertical surfaces only. In general planktonic recruiting gastropods exhibited the most rapid recovery. Forty-two months after the red tide, fucoid algae still dominate both vertical and horizontal surfaces at the study area.

Introduction

Dinoflagellate blooms ('red-tides'), chiefly of Gyrodinium aureolum Hulburt have been recorded several times in Southern Ireland since 1976 (Ottway et al. 1979; Cross & Southgate, 1980; Jenkinson & Connors, 1980; Leahy, 1980; Roden, Ryan & Lennon, 1980; Wilson, 1982) and have resulted in mortalities of farmed rainbow trout in sea-cages in Dunmanus Bay (Parker, 1981). Other species of pelagic and demersal fish on the south coast were also affected by a toxic red-tide in 1976 (Ottway et al. 1979). Owing to the unpredictability of occurrence of dinoflagellate blooms, few studies on the effects of red tides on littoral fauna, and on the subsequent recolonization following the events have been carried out. Previous studies in Dunmanus Bay, Ireland (Leahy, 1980) suffered from a lack of the shores prior to the of information about the structure and dynamics occurrence of a red-tide.

Regular monitoring of the rocky shore biota at Dunmanus Bay (Myers, Southgate & Wilson, 1980) has been carried out since May 1978 and is continuing. The red tide of August 1979 caused dramatic mortalities of a wide range of taxa at Pointabulloge in Dunmanus Bay (Cross & Southgate, 1980).

Several morphological characteristics of the shell in cockles (genus Cerastoderma) were investigated. A significant inverse relationship between rib number and shell curve was revealed in Cerastoderma glaucum. Morphometric and meristic descriptors were correlated with some environmental factors, such as salinity and temperature. Analysis of allometry in C. glaucum and Cerastoderma edule revealed significant differences between the two species. The results are discussed from an adaptive perspective, providing possible hypotheses on the steps which might have driven the evolution of form of the studied species during the process of adaptation to coastal tidal and confined habitats.

The Daily Egg Production Method (DEPM) was used to compute spawning biomass of Engraulis anchoita off Argentina. Estimates of the daily egg production (P0) for the northern stock ranged from 594 to 936 eggs m−2, whereas the annual means of the Patagonian stock ranged from 185 to 605 eggs m−2. The mean values estimated for the Argentine anchovy DEPM parameters were characterized by inter-annual differences greater than inter-regional differences with the exception of P0. For the northern population, the estimates of mean weight of mature females ranged from 15 to 26 g, the relative batch fecundity from 414 to 600 eggs g−1, the spawning frequency (S) from 0.078 to 0.179, and the females ratio from 0.519 to 0.622 of the spawning stock. The estimates corresponding to the Patagonian stock were similar being 15 to 24 g, 418 to 583 eggs g−1, 0.079 to 0.244, and 0.394 to 0.590, respectively. The annual estimates of the spawning biomass for the northern and Patagonian populations ranged between 1.6–3.5 and 0.3–1.5 million metric tons, respectively. A weakness in the application of DEPM was the low precision in the estimation of the daily egg production and the spawning fraction. Alternative methodologies to increase the precision of P0 and S are discussed. In spite of the high variance of the spawning biomass estimates, the use of DEPM offers valuable information to adjust acoustic estimates and provides time series of anchovy population size and biological parameters for basic research.

Two species of genus Squatina were recorded off the coast of Senegal and Squatina oculata is the most commonly caught in the area. Adult males and females studied were over 820 and 890 mm total length (TL) respectively, with the largest male and the largest female recorded being 1450 mm and 1570 mm and weighed 37 kg and 39 kg respectively. The females were significantly heavier than the males. Size at birth was between 226 and 266 mm and weight at birth between 129 and 159 g. Weight of ripe oocytes ranged from 87·65 to 117·60 g (mean SD 101·73±&;8·65). Gestation lasts one year minimum. Squatina oculata is a lecithotrophic species. Counts of ripe oocytes, eggs, embryos and fully developed foetuses showed that ovarian fecundity is significantly higher than uterine fecundity. The former ranged from 8 to 20 (mean SD 12·04±5·80), the latter from 3 to 8 (mean SD 6·22±3·41). There is no relationship between size and the categories of fecundity. Adult males and females were more common than the other categories of specimens landed. Among adults, females were more numerous than males, mainly gravid specimens.

A study was made of the efficiency of a commercially available hydraulic dredge design in use on the west coast of Scotland and of the annual biomass production of two different razor clam (Ensis spp.) beds within the Clyde Sea area. These two parameters, viz fishing efficiency and population annual production, are fundamentally important to any proper attempt to assess the long term sustainability of a fishery. The hydraulic dredge used in this study was found to have an absolute efficiency of 90.1% when expressed in terms of the collected wet weight biomass, representing the first time that the efficiency of a hydraulic dredge of this nature has been measured rather than simply inferred from track width. This indicates that this dredge design has the potential to remove the majority of a clam population, including undersized immature individuals, within a 45 cm swath in a single tow. Annual production estimates were also made for two separate razor clam beds. One population of Ensis siliqua was located in Irvine Bay and the other two populations (one E. siliqua and one E. arcuatus) occurred in a mixed bed on Hunterston Sands. Each location was sampled quantitatively on a regular basis using the same hydraulic dredge. Dredged areas were measured by SCUBA divers so that the population densities could be calculated for each sampling event. Size-classes within each population were identified from siphonal shell breadth measurements and production estimates were calculated using a size-cohort analysis procedure designed for stocks exhibiting recruitment but that do not have separable age-classes. Production of all three populations was low during the study (1.82–18.08 g AFDW 10 m-2) as were the production/biomass estimates (0.01–0.11). These data indicate that populations of Ensis spp. on the west coast of Scotland are slow-growing and typical of K-selected species. These data highlight the conflicting pressures facing any razor clam fishery: the design of extremely efficient hydraulic gear and the slow-growth of the target species. It is clear that the future commercial exploitation of these species will need very careful management to ensure sustainability and avoid fishery over-depletion.

Tapeta were examined of light- and dark-adapted dogfish. Scyliorhinus canicula. The tapetum in the eye of this fish is fixed; pigment processes in the tapetum do not move when a fish is changed from dark to light and vice versa. A black ventral field and a bright dorsal fundus are always present.

The Common Dragonet, Callionymus lyra L., is one of the commonest fishes in the Plymouth area, and is widely distributed in European seas. Recent reports indicate that it occurs also off the coast of West Africa (Fowler, 1936; Poll, 1949). This fish, like others of the genus, attracts attention because, although it has very little economic importance, it is strikingly coloured and the sexes are markedly different. Work has been done on the breeding by Holt (1897, 1898), and by Holt & Scott (1898); on ova and larvae by M'Intosh (1885), M'Intosh & Prince (1889), Cunningham (1891), Holt (1897), Ehrenbaum (1905–9), Fage (1918), Mielck (1925), Duncker, Ehrenbaum, Kyle, Mohr & Schnakenbeck (1929); on seasonal abundance and distribution of post-larvae off Plymouth by Russell (1930–47) and Corbin (1948); and on the skeleton by Günther (1861) and Ford (1937). The mature males are provided with remarkable secondary sexual characters both in coloration and in relative lengths of snout and of median fins, which render them so different from the females that they were originally regarded as different species and known as the Gemmeous Dragonet (male C. lyra L.) and the Sordid Dragonet (female C. lyra L.=C. dracunculus L.) respectively (Donovan, 1808; Yarrell, 1859; Couch, 1863). The sexual dimorphism and seasonal variation of this species has been much studied by Holt (1898), Smitt (1892–95), Gallien (1934), Letaconnoux (1949) and Desbrosses (1949). Very little information has so far been provided about its age and growth, with which the present paper deals.

Wood-boring bivalves of the families Teredinidae and Pholadidae are reported for the first time in Paraíba State, north-east Brazil. During one year, molluscs were collected from mangrove tree logs and from wood panels, along a salinity gradient. Four teredinid (Neoteredo reynei, Teredo bartschi, Nausitora fusticula, Bankia fimbriatula) and one pholad species (Martesia striata) were found.

A study has been made of the feeding activities and reproductive behaviour of the copepod Ascidicola rosea within one of its ascidian hosts, Corella parallelogramma.

Ascidicola rosea feeds on particles which it removes from the food string as the latter is passing through the oesophagus of the host. When active feeding is not taking place, the copepod remains quiescent in the oesophageal bend. An inverted position within the oesophagus is sometimes adopted; this is generally associated with a meagre development of the food string. Certain peculiar structural features—notably the spinous pad on the penultimate segment and the long endopodal setae—are considered to be adaptations which assist the copepod while clinging to the food string.

The eggs of A. rosea are deposited in the ascidian's stomach and the nauplii pass through the host's alimentary canal still enveloped by the inner egg membrane. On reaching the anus, hatching takes place and the nauplii are expelled from the atrial siphon. There are four naupliar and two copepodid stages. Free-swimming life lasts for about 6 days.

Many coral reef fish are assumed to be conspicuous in their natural environment due to their bold and distinct colour patterns. However there have been few attempts to quantify the conspicuousness of coral reef fish under natural photic conditions. In this study, the effects of incident light and background conditions on the potential conspicuousness of four species of Hawaiian reef fish (Chaetodon auriga, Labroides phthirophagus, Thalassoma duperrey, Zebrasoma flavescens) were examined. The optical properties of water, coral and fish colour patterns were measured with an underwater spectroradiometer. Potential conspicuousness was quantified by calculating luminance (brightness) contrast and spectral (colour) contrast within fish colour patterns, and between patterns and natural backgrounds, i.e. water and coral. Under different illuminating and background conditions, the contrast from these fishes was highly variable. Different incident light conditions resulted in significant differences in inherent spectral contrast for L. phthirophagus. All fish had significantly different luminance contrast when the optical properties of the water backgrounds varied. Against coral backgrounds, T. duperrey and Z. flavescens had significantly different luminance contrast and L. phthirophagus and T. duperrey had significantly different spectral contrast. These results have important implications for theories on the adaptive significance of reef fish coloration since the conspicuousness of reef fish appears to be highly dependant on local photic conditions and therefore, some colour patterns may not be conspicuous in the wild as is often presumed.

The newly liberated medusa of Perigonimus muscoides M. Sars has been found to be a Bougainvillia. A specimen from the plankton points to the extreme probability that it can be regarded as synonymous with a previously described medusa, B. nordgaardi (Browne). The name of both hydroid and medusa now becomes B. muscoides (M. Sars 1846).

The systematic importance of the above discovery is discussed, and the genus Rhizorhagium M. Sars 1877 is redefined to include all those species of “Perigonimus” with fixed gonophores, viz. Rhizorhagium roseum, R. sarsi, R. antarcticum, R. formosum, and a new species, R. album, from the Cornish coast.

Variations in the form of the hydroid of Leuckartiara octona are described. The newly liberated medusa of Perigonimus abyssi G. O. Sars is figured for the first time and the species referred to the genus Leuckartiara.

A new Bimeria-like hydroid, Thamnostoma russelli, is described. The characters of the medusa indicate that it belongs to the genus Thamnostoma Haeckel, and the characters of the hydroid show that the genera Thamnitis and Thamnostoma must be united.

Corymorpha annulicornis M. Sars is redescribed from living specimens and the medusa is shown to be Euphysa aurata Forbes. It must henceforth be known as Corymorpha aurata (Forbes).

A new species of Campanulina, C. paracuminata, with its young medusa is described from Plymouth.

Notes are included on Boreohydra simplex, Stauridium productum and Staurocoryne filiformis.

Certain points in the synonymy of all these species are discussed.

In the pelagic habitat, the bodies of resident animals provide much of the ecological substrate available for other organisms to attach, find shelter, and seek food. In Monterey Bay, California, the doliolid Doliolula equus provides substrate for multiple symbionts. These include a mutualist hydroid, commensal ciliates, and a parasitic amphipod. This new doliolid is described based on in situ observations from a remotely operated vehicle, and from the laboratory examinations of 43 colonies comprising hundreds of living, individual blastozooids. Doliolula equus differs from other members of the suborder Doliopsidina in the shape of its body, the length and configuration of its third muscle band, the size of its buccal siphon, and the position of the spiral gland. The new doliolid was found principally at depths between 300 and 400 m. This species is bioluminescent, hermaphroditic, and about one zooid in ten is peppered with orange pigment spots. A variety of other, obviously related, yet undescribed forms has been observed in the eastern Pacific.

Fibropapillomatosis (FP) can be an important conservation threat to green sea turtles (Chelonia mydas) due to its widespread distribution and complex aetiology. Thus, understanding the impacts of FP in sea turtle populations is a research priority towards conservation efforts. The body condition index (BCI), based on straight carapace length (SCL) and body mass (BM), is an accurate indicator of body-nutritional condition that can be used in routine green turtle health evaluations. This study aimed to compare BCI in FP-free (N = 369) and FP-affected (N = 518) green turtles from Brazilian feeding areas. Body condition indices were evaluated in terms of the South-west Atlantic Fibropapillomatosis Score – FPSSWA (mild, moderate and severe), study sites (five Brazilian states), origin (intentional capture, fishery, stranding and afloat) and sex (when known). Curved and straight carapace lengths, and body mass were recorded in order to calculate BCI. Statistical analysis revealed significant differences in BCI among green turtles from different study areas (P = 0.02), and lower BCI values in FP-free than in FP-positive individuals (P < 0.0001). With regards to origin, the highest BCI was found in the intentional capture group (N = 245; 1.47 ± 0.16), followed by fishery (N = 180; 1.46 ± 0.20). Analysis according to sex revealed a higher mean BCI among females than males (P < 0.017). This study provides relevant data on the health and nutritional status of green turtles along the Brazilian coast, in important feeding areas for this species.

Hawaiian spinner dolphins (Stenella longirostris) feed offshore at night on mesopelagic prey and move to protected shallow waters in early morning to rest. We hypothesized that this behaviour would make them particularly sensitive to anthropogenic factors in these rest areas and would affect their overall behaviour and their population frequency. To test our hypothesis we collected data in a known rest area along the north-west coast of the island of Oahu during August of 2001, 2002 and 2003. Using land- and water-based surveys, we evaluated dolphin group size, counted boats, kayaks and swimmers in the vicinity of the dolphins (<40 m) and reported any changes in dolphin behaviour. Our results demonstrated a stable dolphin habitat frequency over the three summers, which emphasizes the critical value of this rest area for this spinner dolphin population. The results also showed an increase in dolphin-oriented activities, but we could not draw any definitive conclusion on their real impacts on spinner dolphin ecology and ethology.

Dasyatis chrysonota is perhaps the most common of the 14 whiptail stingray (Chondrichthyes: Dasyatidae) species known to frequent the temperate coastal waters of southern Africa and like other stingrays they possess life history characteristics that make them vulnerable to over-exploitation. First and 50% maturity (Dw50) were determined for 153 males and 204 females from the Eastern Cape Province of South Africa. Disc width (Dw) for first and Dw50 maturity was estimated at 392 mm and 395 mm Dw, respectively for males and at 500 mm and 505 mm Dw, respectively for females. The reproductive cycle of males, based on gonadosomatic (GSI) and hepatosomoatic (HSI) indices indicates that they are most active during the spring. Females appear to have an annual reproductive cycle with a maximum HSI occurring during the summer and autumn, but it declines steadily through the birthing season reaching a low in the late spring. Fecundity, following a nine month gestation period, averages 2.8 with a range of 1–7. Embryos at six different development stages are described. Dasyatis chrysonota, like other dasyatids, exhibit life history characteristics that make them vulnerable to overexploitation, therefore a precautionary management strategy is advised for this species.

There are various short and incomplete accounts of the capture of prey by Sepia scattered throughout the literature (Grimpe, 1928; Hertling, 1929; Holmes, 1940, are all typical and fairly recent), but I have not found any really satisfactory figures. Those I have seen are little better than rough sketches (Grimpe, 1928, p. 372; Naef, 1923, text-fig. 304b; Tompsett, 1939, plate i, fig. 2) and there do not appear to be any photographs at all. A few observations, and some photographs I have taken recently should therefore be of interest, especially as the photographs reveal some points that do not appear to have attracted attention previously. The final stages of the capture take place so rapidly that the eye fails to observe the details, whereas photographs can be studied at leisure afterwards.

The specimen of Sepia that forms the subject of these pictures was of medium size with a shell about 12 cm. long. It had been living in a tank, with others of about the same size, for several months, during which time it had been fed on living prawns. It was photographed in mid-November when the water temperature was 12.5° C. (in a later paper I shall show that below about II° C. Sepia often ceases to feed). The photographs were taken by flashlight on two evenings between 7 and 8.30 p.m., the tank being lit, for viewing purposes, by a 100 W. bulb in a reflector above one end (the left side in the pictures). Each photograph was taken at sec. with one Baby Sashalite bulb and a synchronizer of my own design, the shutter being released electrically.

When the free-swimming larva of the polychaete tubeworm Spirorbis spirorbis settles permanently on a suitable substratum, it forms a thin, mucous, anchoring tube, which covers only the posterior half of the body. Within 3 h the worm has built a comparatively thick, calcareous tube onto the anterior end of the initial, mucous tube, which later becomes a compressed and folded remnant (Nott, 1973). The volume of calcareous material forming the tube cannot be stored within the body of the larva before settlement and must, therefore, be taken up rapidly from sea water or ingested material.

This paper describes a new species, genus, and subfamily within the Scyphomedusae. Stellamedusa ventana is a relatively large scyphomedusa that reaches up to 9·4 cm in diameter. The medusa is rare, with only seven observations in over a decade of extensive surveys of the Monterey Bay and Sea of Cortez using remotely operated vehicles. Stellamedusa ventana continues the trend found in several other deep-sea semaeostome medusae in lacking marginal tentacles. The exumbrella and oral arms are covered with large nematocyst laden projections which are able to capture food items of various sizes in the laboratory. A large cydippid ctenophore was found in the gut of one captured specimen.