The Cirripede Anelasma squalicola (Lovén) is parasitic on the smooth dogfish, Etmopterus spinax (Linnæus). These fish, which are caught a depth of about 150–180 fathoms, were brought to the University of Liverpool as material for a chemical investigation by Professor Heilbronn and his colleagues. On finding that some of the fish were thus parasitised, Professor J. Johnstone and myself made a study of the general morphology of Anelasma (3).

Evidence is given which suggests that harbour seals use some form of echolocation. When visual cues are reduced, these seals make click vocalizations similar to those of animals which are known to echolocate. They are able to find live fish in total darkness, producing clicks while doing so.

Thermal stress events threaten coral populations by disrupting symbiosis between the coral animal and microalgal symbionts in its tissues. These symbionts are key players in the response of the coral holobiont to elevated temperature. However, little is known about the microalgal symbiont type in select corals in the north-western Philippines and how they contribute to the differential responses of coral species. Based on sequencing of major ITS2 bands from DGGE, the dominant algal symbiont in Acropora digitifera, A. millepora, A. tenuis and Favites colemani was identified to be closely related to ITS2 type C3u, Montipora digitata contained ITS2 type C15, and Seriatopora caliendrum hosted ITS2 types similar to C3-Gulf and D1. Thin branching corals, such as A. tenuis and S. caliendrum, exhibited the greatest reduction in photochemical efficiency (Fv/Fm) and symbiont density at elevated temperature, followed by M. digitata and A. millepora, to a lesser extent. A. digitifera and F. colemani were least affected by the temperature treatment. Reduction in Fv/Fm and symbiont density was more apparent in A. tenuis and A. millepora than in M. digitata and F. colemani, although these species all host ITS2 type C3u symbionts. These results suggest that the impact of elevated temperature is influenced by factors apart from symbiont type. This highlights the importance of further studies on the diversity of corals and their microalgal symbionts in the region to gain insights into their potential resilience to recurring thermal stress events.

A new species of the genus Onchidoris is described from the south-western Atlantic, on the coast of Brazil, in the States of Rio de Janeiro and São Paulo. To date, the genus Onchidoris is known almost exclusively from the northern hemisphere, especially the Atlantic coast of Europe and the Mediterranean Sea. The single previous record from the southern hemisphere is Onchidoris maugeansis, described from Australia. This is the first record of the family Onchidorididae from the coast of Brazil. Onchidoris brasiliensis sp. nov. is very similar to Onchidoris depressa, from England and the northern coast of Spain, but is distinguished by the presence of a triangular protuberance on the edge of the inner lateral radular tooth and a wide closed branchial circle with tubercles inside. Furthermore, the egg mass of O. brasiliensis sp. nov. contains a single row of eggs, whereas that of O. depressa has multiple rows. Onchidoris brasiliensis sp. nov. has lecithotrophic development, the first record of this type of development in the genus. There is a relationship between O. brasiliensis sp. nov. and the bryozoan Parasmittina protecta.

Dense populations of Prorocentrum micans are reported from the Galway Bay area in 1980 and 1981. At one location a density of llx106 cells dm-3 was found co-incident with a bright red colour in the water. High concentrations of chlorophyll a and high levels of dissolved oxygen were also associated with the blooms.

An appendicularian belonging to the family Oikopleuridae, subfamily Bathochordaeinae, Mesochordaeus bahamasi gen. nov., sp. nov., is described from a single specimen collected at mesopelagic depth in Bahamian waters. As the subfamily was founded with only one genus (Bathochordaeus), new descriptions are given for the subfamily and the two genera.

Eighty-seven specimens of Bathothauma lyromma from the ‘Discovery’ collections have provided new information on this unusual species. The size range represented is sufficient to trace the development from small larvae to near adult. Information on sexual development is also given. Twenty-nine specimens from opening-closing nets show that Bathothauma occupies the depth range 100–1250 m, with smaller specimens living at shallower depths than the larger ones.

This study compared the sizes of zooids in colonies of the cheilostome bryozoan Cribrilina annulata collected from two differing substrata (stones and algae) in three regions of the White and Barents Seas. Zooids of the colonies growing on stones were larger than those in the colonies growing on the thalli of the red alga Odontalia dentata. Size differences of the zooids in the colonies growing on the same substratum in different regions were minor. Three possible explanations for these dimensional differences of zooids are discussed: (1) larvae of different sizes settle on different substrata; (2) ancestrulae of different sizes survive on different substrata; and (3) substrata influence the ancestrulae's size.

A towed trawl simulator sledge (TTSS2) for collecting quantitatively small macrobenthic animals disturbed by the passage of otter trawl groundrope typical of the local fishery is described and illustrated. The TTSS2 was towed from a surface vessel at a speed within the range of commercial trawls, incorporating three sampling nets that open and close by means of an electro-mechanical system. An odometer in contact with the seabed provided a continuous record of the trawled ground. The degree of efficiency of the TTSS2—by means of the attached groundrope that stirs up the surface of the bottom ahead of the nets—was tested in the northern continental shelf of Crete (eastern Mediterranean). Additional trials with a much heavier groundrope were also performed. Analysis and comparison of TTSS2 samples with endobenthic, hyperbenthic and planktonic samples collected by means of conventional sampling gears indicate the presence of a well-defined and distinct fauna in the plume of resuspended sediment behind the groundrope.

Reports from anglers and divers indicated that in late August and September 1978 a substantial mortality of the bottom fauna and fish had occurred in the bays along the south coast of Cornwall, particularly in the St Austell area. It was therefore decided to carry out an investigation by diving and at the same time collect water samples from affected areas for further analysis. The following notes record the observations made during the period 19–28 September at various localities but mainly in St Austell Bay (see Fig. 1).

In the course of work on the life-history and biology of the Raiidæ in the English Channel, and especially of R. clavata, the most important species commercially (4, p. 9 et seq.), it has been found necessary to attempt to disentangle the migrations of sexually mature fishes from those of juvenile individuals by means of marking experiments. In both sexes sufficiently small individuals could with safety be written down as juveniles and the largest of both sexes as adults. There remained, however, a considerable but ill-defined range of sizes (different in the two sexes) within which might be found fishes of all stages—juveniles, adolescents and adults.

INTRODUCTION

Until recently saturated sterols – stands – were not thought to play an active biochemical or physiological role in organisms. They were generally considered to be diagenetic products of the microbiological reduction of the common natural product Δ5sterols and as such have been reported in sediments (e.g. Gaskell & Eglinton, 1975).

Prior to the regular use of capillary gas liquid chromatographic (GLC) and gas chromatographic-mass spectrometric (GC-MS) techniques the majority of sterol analyses had been performed on packed column GLC. It is now well known that in the analysis of some of the complex mixtures of sterols which commonly occur in the marine environment, the use of packed column GLC techniques alone is an inadequate procedure (e.g. Ballantine; Roberts & Morris, 1976; Ballantine et al. 1977). Certainly complete resolution of the sterol-stanol pairs cannot normally be achieved on packed columns and identification of the components within each peak has to be made by multiple mass spectral scans across each peak (Ballantine et al. 1976). With the advent of techniques with better resolving powers, significant amounts of natural product stands have been found in a wide spectrum of phyla including molluscs, sponges coelenterates, echinoderms, annelids and tunicates (Morris & Culkin, 1977 and references therein; Ballantine et al. 1976; Ballantine, Lavis & Morris, 1979, 1981; Voogt, 1976; Ballantine et al. 1977; Ballantine et al. 1978; Gupta et al. 1979). In some instances the stanols have been found to account for over 50% of the animals component sterols.

As the sterol profile of marine invertebrates becomes better understood it is clear that stanols are important biochemical constituents of many of these organisms; but little is known of their significance in any biochemical or physiological role.

Parorchis acanthus is a Trematode described by Nicoll (1907) from the bursa Fabricii and rectum of the Herring Gull, Larus argentatus; in 1906 he first described it as Zeugorchis acanthus. Originally found at St. Andrews, it is now known to be common at Millport and also occurs in gulls from the Northumberland coast, and probably is abundant elsewhere. Nicoll found it once in the Common Gull, Larus canus. In 1907 (Lebour, 1907) one of the present writers described a cercaria occurring in rediæ from Purpura lapillus. This was named Cercaria purpurœ sp. inq., and afterwards identified with young stages of Parorchis acanthus in the Herring Gull (Lebour, 1914). It was thus shown that the first host of this Trematode is Purpura lapillus and the final host the Herring Gull, but the intermediate host was unknown. Localities for the cercaria were Loch Ryan, Wigtownshire; Budle Bay, Fenham Flats and Cullercoats in Northumberland; Robin Hood's Bay in Yorkshire; and Millport. Adults occur at St. Andrews, Northumberland coast and Millport, as already stated.

The Cercaria appeared to be closely related to Echinostomum cercariæ, and it was suggested (Lebour, 1914) that the intermediate host would probably be some marine bivalve, as it is often so with Echinostomum (e.g. E. secundum in Mytilus edulis and Cardium edule, E. leptosomum in Scrobicularia tenuis). This suggestion now proves to be correct, and we are able to show that the intermediate host of Parorchis acanthus is Mytilus edulis or Cardium edule.

On August 13th, 1921, at the Millport Station some larval cercariæ were noticed by Elmhirst swimming in a small glass aquarium, which contained a collection of Purpura lapillus, Cardium edule and Mytilus edulis.

The phenotypic shell shape variation of Mactra isabelleana was tested using the geometric morphometric method. Four localities were sampled along the Río de la Plata estuary and the coast of Buenos Aires province. Principal component analysis and canonical variates analysis of the first principal components were performed to reveal the shell variation and differences among localities, respectively. The specimens from different microhabitats mostly overlapped, although differences in shape were observed in the development of the umbo, the enlargement of the dorsoventral axes and the elongation of the posterior end. The ecological and physical parameters that could influence shell shape variation are discussed.

Individual growth histories of the shortfin squid Illex argentinus were reconstructed in 1512 individuals obtained during seven years of commercial exploitation in southern-south-eastern Brazil. Growth increments were directly measured on the gladius dorsal surface from the anterior part to posterior end in two-thirds of the entire length. Gladius growth increments were deposited at the same rate as statolith rings and the daily nature of the growth increments was supported. Because gladius length is strongly related to mantle length, growth increments closely approximated mantle length growth rates, allowing the reconstruction of both size- and age-dependent growth. Individual reconstruction was possible between 4 and 347 mm of gladius length, almost the entire life cycle of the species. The variability of the acceleration in gladius growth evidenced four life history transitions where the most noticeable occurred between paralarval/juvenile stages, delimiting male/female size differentiation. The changes in acceleration in growth throughout the size-range may be influenced by the thermal gradients experienced by individuals during life history events transitions in Brazilian waters.

The exposure to discharging nematocysts of the eolid nudibranch Cratena peregrina feeding on polyps of the hydroid Eudendrium racemosum was examined. The smaller size-class of microbasic eurytele mastigophor nematocysts is located on the tentacles of the hydroid polyps, while the larger size-class of holotrichous isorhiza nematocysts is located on long cnidophores and basal rings of some polyps. Discharging nematocysts of the tentacles do not appear to have damaging effects on the dorsal appendages of the snail, the cerata. In contrast, contact of a cnidophore with a ceras elicits massive discharge of nematocysts, which results in adherence, membranolysis and local destruction of the epidermis within seconds. The differential locations and effects indicate that the small tentacle nematocysts serve for capturing prey, while the large cnidophore nematocysts serve for the hydroid's defence. Both small and large, discharged and intact nematocysts were found in the pharynx and stomach of the snail after feeding. Thus, the alimentary tract appears to be efficiently protected against discharging nematocysts. Small and large intact nematocysts, which were capable of discharge, were also found in the cnidosacs.

The spatial and temporal patterns of variation of a tropical soft-bottom fish community sampled by a shrimp trawl and a fish trawl were compared at two sites, North and South Bay, of St Vincent Bay, New Caledonia. Results indicated that the species richness and particularly the species composition were related to the type of trawl. However, the overall density and biomass, species diversity, and evenness did not vary significantly as a function of gear type. The same species dominated the catches of the two trawl types, but differences appeared between density, biomass and mean weight of particular species, calculated from the shrimp and the fish trawl catches. The spatial variations of the community structure were comparable between the two gear types, though the composition of the species assemblages were not the same. Differences appeared for the temporal structures. These differences were insignificant in one of the sampled sites (North Bay), but more important in the other site (South Bay), where species diversity, size range of the individuals, and shape diversity of fishes were more important. However, the major differences between the community structures remained the same, independent of sampling gear type. These results validate studies comparing spatial and temporal patterns of variations in general characteristics (i.e. number of species per haul, density, biomass, species diversity and evenness) of tropical soft-bottom fish communities determined by shrimp and fish demersal otter trawls. This also validates the determination of species assemblages especially spatial assemblages. However, important problems may arise when more particular points are studied, such as species composition of the communities, determination of the characteristic species of the assemblages, or study of a particular species.

In order to provide a better characterization and understanding of the brine shrimp Artemia salina life-cycle, different ecological and biological parameters were taken out monthly during two periods from November 2005 to April 2006 and from November 2006 to April 2007 in Sabkhet El Adhibet (south-east Tunisia). Variation of water temperature, salinity, pH, dissolved oxygen, nutrients (orthophosphate, nitrites, nitrates and ammonium) and phytoplankton density were monitored. The Artemia population was also surveyed. Artemia were present in the site with salinity between 32.2 and 281.7 g l−1 and water temperature between 12.1 and 25.4°C. The pH ranged from 7.6 to 9 and dissolved oxygen concentration from 3.4 to 17.5 mg l−1. Minimum and maximum values of phytoplankton density were 0.19 and 14.59 106 cell l−1. In addition, the nutrient analysis registered showed that nitrate and ammonium represent the major nutrient. The Artemia population density fluctuated between 0.22 and 38.57 individuals per litre. The male:female ratio was dominated by the males. Artemia from Sabkhet El Adhibet showed variability in fecundity (total offspring and brood size) as well as in the ratio encystment/oviviparity. The individual fecundity fluctuates between 29.4 and 70.2 cysts and 17.8 and 69.8 nauplii. Finally, the influence of physical and chemical parameters as well as phytoplankton density over the Artemia population was noticed.

Seasonal distribution of the ciliated protozoa was studied in the west part of Kaštela Bay during 1995. These are the first data of the annual distribution of four size categories of non-loricate ciliates and tintinnines in the coastal area of the central Adriatic Sea. The maximum densities of ciliated protozoa were recorded during the spring and autumn, when they could act as important factors of ‘top-down’ control. Contributions of non-loricate ciliates and tintinnines to the total of ciliated protozoa were 72 and 28%, respectively. The highest density of non-loricate ciliates was registered at the surface in September (1400 ind l−1). Annual variability of the non-loricates density was mostly influenced by changes in numbers of the second (103–104 μm3) and third (104–105 μm3) size categories and they constituted 86% of the total non-loricate counts. Non-loricates with biovolume <103 μm3 were the most abundant during the colder part of the year while those with biovolume >105 μm3 dominated during the summer. The highest density of tintinnines (718 ind l−1) was recorded at 5-m depth in May. Quantitatively, the most important tintinnin species was Helicostomella subulata. The results suggest a complex influence of biotic and abiotic factors on the annual distribution of ciliated protozoa.

Two hydrographic cruises have been carried out in the Irish Sea during the winters of 1965 and 1966. It has been found that near the Welsh Coast reactive silicate concentrations were remarkably constant and lower than expected. In contrast, near the Irish coast there were marked variations in reactive silicate concentrations and the values found were considerably higher than those for the Welsh coast.