Little is known about the early development stages of Parablennius ruber. In this paper the following stages are described, and illustrations provided for the first time: middle stage egg, late stage egg, yolk-sac larva and preflexion larva. Recently laid eggs were spherical and orange, attached to the substratum in rock crevices. Eggs measured 1.02 mm in diameter. Newly hatched larva measured 4.65 mm total length and had the mouth closed and the anus open, fully pigmented eyes and a big yolk sac. Pectoral fins were present, rounded and not radially pigmented. Yolk was absorbed in 2–3 days at room temperature. Preflexion larvae had pointed pectoral fins, bigger eyes, well developed lips and strong jaws. Operculae were open. Orange chromatophores began to be noticeable between the eyes.

The new species Abarenicola wellsi n. sp. from the Falkland Islands is described along with a re-description of Abarenicola brevior n. stat. with which it had previously been confused. The two species are distinguished using both morphological and molecular techniques, new characters are described and previously recognized characters are clarified, all of which support the assignment of species status as opposed to subspecies. Both species are part of the Abarenicola assimilis ‘group’ within which all taxa were originally described as subspecies. The group as a whole is re-evaluated and all members are elevated from subspecies to species status based mainly on the new characters of shape, distribution and pigmentation of the proboscidial papillae. The group now consists of six species: Abarenicola assimilis n. stat., A. brevior n. stat., Abarenicola devia n. stat., Abarenicola haswelli n. stat., Abarenicola insularum n. stat. and A. wellsi n. sp.

1. In the course of three trips to the herring grounds in the vicinity of St. Ives five seals were sighted. Seven others were also seen at various other times and places in the course of five days spent in that locality.

2. During a single night at sea in Port Isaac Bay eight seals were sighted.

3. It was obvious from the movements of certain of the seals observed on the fishing grounds that they were attracted to the herring nets.

4. Direct evidence that the seals actually remove fish from the nets was not obtained.

5. Damage done to drift nets by seals is negligible.

6. Grey Seals (Halichœrus grypus) are present in considerable numbers, and are probably the commonest seals in Cornish waters.

7. Brown Seals (Phoca vitulina) appear to be few—they may even be rare—around Cornwall.

8. There is at least one seal colony of considerable size in certain caves near Boscastle. This appears to consist of Grey Seals. Probably other such colonies exist on the Cornish coast.

9. Clupeoid remains have been found in two out of the three Grey Seal stomachs which have been examined.

10. Further and more exact knowledge of the habits and relative abundance of Grey and Brown Seals around the Cornish coast is desirable.

Scats (N=200) of harbour seals (Phoca vitulina) were collected from haul-out sites on the Island of Mousa, south-east Shetland, during July, August and September 1994. A total of 5,531 fish otoliths were identified in scats and measured to reconstruct fish lengths and weight. Gadid fishes dominated the diet of harbour seals on Mousa during the study period, both in terms of weight and the frequency with which they occurred. There was evidence for the existence of temporal trends. Over the period July–September the importance of gadids in the diet increased while that of sandeels declined. These temporal trends are probably associated with changes in prey availability. Comparisons of the size of sandeels, herring and whiting eaten by seals with trawl catches suggest that seals were probably not size-selective, but a corollary of this is that, while otolith size is reduced during passage through seal guts, application of correction factors derived from captive feeding experiments led to over-estimates of fish size.

An area in the central North Sea was surveyed in November 2011 in order to estimate the abundance and density of harbour porpoises (Phocoena phocoena). A total of 2833 km of pre-determined trackline were acoustically surveyed, of which 28% included visual effort. The poor sighting conditions during the survey limited visual effort and demonstrated the advantage of using acoustic techniques for studying harbour porpoise in winter months. Absolute abundance and density estimates were calculated from acoustic encounter rates using estimates of probability of detection and mean group size. The density of harbour porpoises in the west of the survey area was almost double that in the east, with UK waters to the south-west of the Dogger Bank having the highest density of the area surveyed. The overall acoustic encounter rate was higher than most other surveys in the North Sea. The mean density across the survey area of 0.63 (95% CI 0.27–1.52) individuals km−2 and distribution of porpoises was similar to that documented in the summer suggesting that high abundance of harbour porpoises in the west of the North Sea is not confined to summer months. This information is particularly relevant given plans for the construction of a large offshore wind farm on the UK section of the Dogger Bank; the resulting impacts, including acoustic disturbance from pile driving, will potentially affect substantial numbers of harbour porpoises.

Halicarcinus planatus is the only species of the genus occurring at the southern tip of South America, in sub-Antarctic, cold-temperate waters. Previously it has been shown that the population from the estuary of the Deseado River presents a spatial segregation by sex, a complete overlapping of sizes among adolescents and adult females. Females go through two reproductive seasons, separated by a resting period during late summer and early autumn, and 7 to 8 spawns are produced following a single mating. The aims of the present work were to evaluate the duration of the embryonic development until hatching during successive spawning, to determine the fecundity and to discuss the adaptive reproductive strategies of this population. Breeding occurs from nearly 2°C to above 16°C. The incubation period lasts nearly 100 days in winter and between 30 and 40 days in summer. The fecundity ranged from 210 to 2150 eggs, it differs between successive spawning and a positive relationship was found between fecundity and carapace width. This population has the highest fecundity compared to other populations, but also compared to other species of the genus. The high number of successive spawns is directly linked to the increase of seawater temperature by the end of spring and during summer. This way, this species would be very well adapted to live in the more temperate waters of Patagonian coasts.

Various marking techniques have been used in ecological studies of starfish as well as other benthic animals (Nielsen, 1992). They include the attachment of tags (Feder, 1955), staining with dye (Hancock, 1958), inscription with sharp pencil (Scheibling, 1980), and branding (T.K, unpublished data). These methods have been used in mark-recapture surveys over durations of several days in order to study the diurnal activity rhythmn (Burla et al., 1972), movement after displacement (Pabst & Vicentini, 1978), and feeding and movement rates (Keesing & Lucas, 1992). However, these marking techniques on starfish have never been quantitatively evaluated for their durability and detrimental effects on the starfish.

Accordingly, in the present study, brand marks on Asterina pectinifera (Müller & Troschel) were examined in the laboratory in terms of their durability and impact on mortality and growth. For Echinodermata, branding has been used mainly on Holothuroidea like Stichopus japonicus (Arakawa, 1990). However, it can also be used for starfish to identify individuals by marking patterns on the body (T.K., unpublished data). The present study tested the effects on the growth and mortality of A. pectinifera. It also examined the durability of brands for distinguishing individuals of a branded group from individuals of an unbranded group, and the durability for identifying individuals with specific coded brand marks.

Two hundred starfish were collected in Maizuru Bay (35°29′N 135°22′E) in September 1995, and the size was measured. The five arms of each individual were measured from the centre of the disc to the arm tip (mm) to determine the mean radius (R0).

A new species, Aciconula tridentata sp. nov., is described from the Brazilian coast. The type material were collected from Praia de Suape, Cabo de Santo Agostinho, Pernambuco, Brazil. This new species differs from all its congeners in having the propodus palm of male gnathopod 2 bearing a 3-dentate projection. Additionally, A. tridentata sp. nov. can be distinguished from A. australiensis and A. miranda in lacking a setose hump proximally in article 1 of the peduncle of antenna 1; the outer plate of maxilliped reaching the end of palp article 1, and the female pereopod 4 is 3-articulate. A key to species of the genus is provided.

A meeting on Plant-Animal Interactions in the Marine Benthos was held in Liverpool in September 1990, organized by the Sy sterna tics Association in their Symposium Series, and supported by the Marine Biological Association. The following six papers were first presented at this meeting:

The wedge sole (Dicologoglossa cuneata, Moreau 1881) is a commercially important species for the artisanal fleet operating off the south-western Iberian Peninsula. During 2004 and 2005 a study was undertaken aiming to provide a scientific basis for management. Data collection included information on aspects of the fishery, spawning season, size at first maturity, tangle and gill-net selectivity. Seven nominal mesh sizes were used (40, 45 and 50 mm tangle nets and 40, 50, 60 and 70 mm gill-nets). Spawning lasts from December to June, with peaks in March and May. Length at first maturity for females was estimated at 18.5 cm. Catch rates decreased sharply with increasing mesh size, with tangle nets providing the highest yields. The log-normal selectivity model provided the best fit for specimens that were wedged. The higher catch-per-unit-effort of the smaller mesh sizes and the modal length of the fitted selectivity curve being below the size-at-maturity for wedge sole, suggests that the 50 mm nominal mesh size tangle net is the most appropriate for ensuring the fishery sustainability. Nevertheless, the minimum legal size should increase to at least 18 cm and a time–area closure should be implemented off the Guadiana River mouth.

This special issue of JMBA papers on the gelatinous plankton is dedicated to Sir Frederick Russell, Director of the Plymouth Laboratory of the Marine Biological Association from 1945 to 1965 and pioneer in the study of gelatinous plankton.

The complete larval development of the lobster shrimp Leonardsaxius amurensis (Kobjakova, 1937) (Decapoda: Axiidea: Axiidae) is described and illustrated for the first time. The first zoeae of this species were collected from the plankton samples and reared in the laboratory before moulting to the megalopa. A molecular genetic analysis based on comparison of partial mitochondrial COI, 12S rDNA and 16S rDNA sequence data confirmed the identity of axiid larvae found in the plankton and L. amurensis adults collected in the same area. The larval development of L. amurensis includes five zoeal stages and a single megalopa. Zoeae I of L. amurensis are characterized by the presence of one short posterodorsal spine on the fifth pleonite in contrast to the larvae of related sympatric species Boasaxius princeps having four posterodorsal spines on the pleonites 2–5. Leonardsaxius amurensis occupies an intermediate position between lobster shrimps with abbreviated pelagic development (2–3 zoeal stages) and species with long development (up to eight zoeal stages). Thus, the number of zoeal stages in the family Axiidae varies widely, similarly to that in the families Callianassidae and Upogebiidae.

The rocky intertidal communities of Ireland contain a mix of cold- and warm-adapted species, however the spatial distribution of these communities has not been investigated in a systematic way. Based on a benthic community dataset collected in 2003 at 63 sites, several statistical analyses were combined with the aims of (i) detecting groups of similar communities and their spatial arrangement, (ii) relating these groups to environmental factors and (iii) identifying the species that drive the different community groups. Sørensen's index suggested two marine community groups, one of the east and south-east (termed ‘east’) and the other in the west, south-west and north (termed ‘west’). A second partition based on combined wave exposure and sea surface chlorophyll comprised four groups, as did a further partition based on combined sea surface and air temperatures. The spatial arrangement of wave height plus chlorophyll conditions agreed reasonably well with the binary marine community partition, but the temperature partition did not. The ‘east’ community appeared to be associated with low wave height and chlorophyll conditions. The species that were most influential to the ‘east’ community were Balanus crenatus, Austrominius modestus and Fucus vesiculosus. The ‘west’ sites were associated with high wave height/low chlorophyll (with some variation in this due to local shelter) and the species Paracentrotus lividus, Chthamalus stellatus, Alaria esculenta and Himanthalia elongata. A longitudinal pattern rather than one associated with latitude was evident in this marine community and local drivers rather than temperature clines appeared most important for the dominant community patterns.

The effects of winter flooding on the intertidal macrobenthic assemblages in the Guadiana estuary were studied by analysing several ecological parameters (abundance, biomass, species richness, diversity, degree of dominance of annelids and deposit-feeders species and number of predator species) as well as changes in the composition of the assemblages. Significant and systematic differences were found in the values of the ecological parameters, especially between winter and summer. We found a significant interaction between the factors ‘time’ and ‘site’, attributable to changes in abundance and composition of the assemblages. The assemblages showed a predominance of some opportunist species in most of the estuary after the flooding, suggesting that these species benefited from the new environmental conditions. Conversely, the assemblages in the mouth of the estuary were severely affected as was shown by the negative changes in biomass, species richness and diversity. These converse responses of the intertidal estuarine assemblages represent effects of flooding different from both catastrophic and negative effects on macrofaunal assemblages.

Mating behaviour of the leucosiid crab Pyrhila pisum was studied in the laboratory and tidal flats in Japan. Most males actively approached females. Males started guarding females without any courtship behaviour (pre-copulatory guarding). Males began copulation within several minutes. The copulation continued for about 1–2 h, following which males began post-copulatory guarding. This guarding lasted from almost 0 to over 3 days, but its duration was generally much longer than that prior to copulation. Release of guarding was not linked to ovulation by females. Long-term rearing experiments revealed that both sexes of P. pisum could copulate multiple times with various mates. Developmental stages of the embryos recorded from copulating ovigerous females widely varied; their timing of copulation may not be fixed. In the tidal flat, wandering males frequently contacted with other individuals, but without distinguishing single males, single females and pairs of P. pisum, or Hemigrapsus takanoi. Male P. pisum cannot recognize female conspecifics, and they approach their mates relying only on vision, without using any attractive cues from females. In cases in which males encountered pairing crabs, they successfully stole the females when the guardians were smaller than the challengers, suggesting that effectiveness of guarding depends on male size. Among the mating pairs, males tended to be larger than females, and the tendency of size-assortative mating was weak or absent. Therefore, the mating behaviour of P. pisum is not elaborate, although their guarding behaviour may contribute to improve success to some degree.

A new species of physonect siphonophore, Halistemma transliratum sp. nov., is described from two specimens collected at mesopelagic depths in Bahamian waters by the submersibles ‘Johnson-Sea-Link’ I and II, and comparisons are made with the established species of that genus.

Several poorly known species of the family Syllidae (Annelida) have been revised and re-described. New diagnosis and taxonomic remarks are provided for Erinaceusyllis erinaceus, Opisthosyllis neglecta comb. nov., Parapionosyllis parapionosylliformis comb. nov., Prosphaerosyllis semiverrucosa comb. nov. and Amblyosyllis granosa.

Actions to rescue, rehabilitate and release calves of manatees are the main initiatives and strategies for conservation of the species in Brazil. The survival rate of animals in a natural environment and the reproductive success, identified by birth records, are some of the indicators used to estimate the release success for manatees. This study evaluated the effectiveness of releases of West Indian manatees based on the reproductive success of rescued animals that were released back into the wild in Brazil. Twenty-two female manatees were released in the states of Alagoas (into an extinct area) and Paraíba (into an existent population) from 1994–2020. Six females gave birth to 13 calves, all in Alagoas State. The average age of the first calving event was 11.7 (±1.49) years and 8.0 (±1.41) years after release. Among the females that had more than one calving, the average was 3.6 (±1.18) years between each calving. All calves observed were born alive; nevertheless, three (23.1%) died a few weeks after birth. In general, females rehabilitated in captivity and released in the wild were able to reproduce, especially in protected areas. This study emphasizes the need to intensify actions for the conservation of manatees and their habitats in order to achieve healthier wild populations.

The compilation of data on alien Sipuncula species reported from the Mediterranean Sea to date yields a total of eight species belonging to four families. Four species have become established in the area, while two species are classified as casual and two as cryptogenic. The pathways of the introduction of alien Sipuncula species were shipping and the Suez Canal. The eastern basin had the higher number of alien Sipuncula species (seven species) mainly due to its proximity to the Suez Canal and dense shipping traffic. Among these species, Aspidosiphon (A.) mexicanus has a wide distributional range in the region, but was considered as a cryptogenic species. The majority of alien Sipuncula species were found on soft subtrata in the region. Brief descriptions of the alien Sipuncula species and their distributional and ecological characteristics are given.

The study of the digestive epithelium in Sagitta setosa, S. serratodentata, and S. pacifica revealed only a few morphological and cytological differences among the three species. The gut was divided in two main regions. The first is the cephalic region where the epithelium is composed of three distinct cell types (S1, S2, and S3), the ultrastructure of which is probably specialized either for the synthesis of mucosubstances (S1), or enzymes (S3), or both (S2). The second region of the gut extends to the trunk and is mainly composed of the intestine and a short vertical rectum. No intestinal diverticula were observed. The intestinal epithelium displayed two ciliated cell types, anteriorly, a secretory cell type (S4) containing large mucus-like granules, and a second cell type (A) predominated in the posterior part of the intestine. A-cells appear to have two main functions. Although they exhibit secretory granules, they also display typical endocytotic features in their upper half, i.e. coated vesicles, a well-developed tubulo–vesicular network and two distinct types of digestive vacuoles corresponding to an endosome–lysosome-like system. From the distribution and presumed function of the cells, the gut may be divided in two main functional units, i.e. the cephalic and trunk units.