A female Octopus macropus, the first ever observed spawning, attached eggs (4·0×1·2 mm, with a chorion stalk 4 mm in length) individually or in clusters to a hard substrate, and brooded them till hatching. Hatchlings measured 4·0 mm in dorsal mantle length, 5·5 mm in total length and were planktonic; their short arms had seven suckers each, the outer demi-branch of each gill had ten lamellae. The chromatophore pattern confirmed an earlier identification of young individuals from the plankton (Naef, 1923).

The diets of marine predators are a potential source of information about range shifts in their prey. For example, the short-finned squid Illex argentinus, a commercially fished species on the Patagonian Shelf in the South Atlantic, has been reported in the diet of grey-headed, Thalassarche chrysostoma; black-browed, T. melanophris; and wandering, Diomedea exulans, albatrosses breeding at Bird Island, South Georgia (54°S 28°W) in the Southern Ocean. Tracking data suggest that these birds may feed on I. argentinus while foraging in Southern Ocean waters during their breeding season. This led to the hypothesis that I. argentinus may occur south of the Antarctic Polar Front. To test this hypothesis, we used stable isotope analyses to assess the origin of I. argentinus. We compared I. argentinus beaks from the diets of the three albatross species with beaks of cephalopod species endemic to the Patagonian Shelf and others from the Southern Ocean. Our results show that I. argentinus from the diet of albatrosses at Bird Island have δ13C values in the range −18.77 to −15.28‰. This is consistent with δ13C values for Octopus tehuelchus, a typical species from the Patagonian Shelf. In contrast, Alluroteuthis antarcticus, a Southern Ocean squid, has typically Antarctic δ13C in the range −25.46 to −18.61‰. This suggests that I. argentinus originated from warmer waters of the Patagonian Shelf region. It is more likely that the albatross species obtained I. argentinus by foraging in the Patagonian Shelf region than that I. argentinus naturally occurs south of the Antarctic Polar Front.

Breeding and population statistics were assessed from February 1993 to September 1995 in a mixed population of the mudsnails Hydrobia neglecta and H. ulvae in the intertidal zone of a macrotidal bay on the Atlantic coast of Brittany, France. The biology of H. neglecta in the mixed population was identical to that found earlier for the same species when living allopatrically elsewhere in the bay, and was also that generally characterizing directly-developing species of Hydrobia that occur in coastal lagoons. The population of the larviparous H. ulvae also showed various features otherwise typifying lagoonal populations of this species: very high juvenile mortality, repeated failure of whole cohorts to recruit, and an age structure dominated by large and relatively old individuals. The number of eggs per capsule was normal for an intertidal H. ulvae population but the number of capsules laid was remarkably low. Why both species should behave in this intertidal marine habitat as if it were lagoonal is unknown. The failure of the cohorts of H. ulvae deriving from spring eggs in the bay may help explain why the majority of lagoonal populations of this species are dominated by old mudsnails and show negligible recruitment. There was no evidence of competitive displacement of H. neglecta by H. ulvae in spite of received wisdom that H. ulvae is the competitive dominant under fully marine conditions; mortality of H. ulvae was more than three times that experienced by H. neglecta regardless of age of the snails.

Four new species of cheilostome Bryozoa from the hippothoid genus Antarctothoa (formerly subgenus Antarctothoa, Moyano 1987) are described. Antarctothoa bougainvillei (d'Orbigny) and Antarctothoa dictyota (Hayward) are re-described from material collected from Patagonia and South Georgia respectively.

Three species of cirrate octopod are reported from deep-sea collections around the coasts of Greenland and Iceland in the North Atlantic. Twenty-one specimens of Stauroteuthis syrtensis were caught from east and west Greenland at depths of 258–1321 m, representing a considerable geographic and bathymetric extension of the range. Nine specimens of a putative new species of the genus Opisthoteuthis are reported, and are the first records of this genus in the area. Nineteen specimens of the circum-Arctic species Cirroteuthis muelleri add significantly to our knowledge of the distribution this species. Latitudinal patterns in the bathymetric distribution of C. muelleri and S. syrtensis suggest temperature is the principal controlling factor.

The present study provides novel information on carapace width-weight (CWR) relationship and growth parameters of the mud crab Scylla olivacea (Herbst, 1796) inhabiting the Pichavaram mangroves, east coast of India based on length frequency data sets during June 2010 to May 2012. CWR revealed linear regression between carapace width and weight in both sexes, and overall CWR exponent (b) values acquired for males and females are 3.035 (r 2 = 0.962) and 2.925 (r 2 = 0.933) respectively. The growth parameters, CW∞, K and t o derived for males and females were 148.05, 0.762 year−1 and −0.637 and 138.80 mm, 0.856 year−1 and −0.681 respectively. The growth of S. olivacea was assessed through various methods in such a way that the outcome of one method functions as a rider, check and control over the other.

The Atlantic–Mediterranean transition zone between the Alborán Sea and the Gulf of Cádiz constitutes the most prominent marine geographic barrier in European waters and includes known phylogeographic breaks such as the Strait of Gibraltar and the Almería-Oran Front. A genetic shift in this area has been previously documented for the European littoral shrimp Palaemon elegans. Here we carried out a phylogeographic analysis with the congeneric and sympatric species Palaemon serratus to test for similar intraspecific genetic differentiation and geographic structure. This littoral prawn is distributed in the Northeastern Atlantic Ocean, the Mediterranean Sea and the Black Sea. We compared DNA sequences from the mitochondrial genes Cox1 and to a lesser extent from 16S rRNA of several Atlantic and Mediterranean populations. Furthermore, sequences from the nuclear gene Enolase were included for corroborating differences between Mediterranean and Atlantic individuals. A pronounced genetic differentiation was detected between the Mediterranean and Atlantic populations, amounting to 10.14% in Cox1 and 2.0% in 16S, indicating the occurrence of two independent evolutionary lineages. Interestingly, specimens from the Atlantic Gulf of Cadiz cluster together with the Mediterranean individuals, indicating that a biogeographic barrier appears to be located west of the Strait of Gibraltar.

The present paper is the first annotated account listing all species of Cirripedia: Thoracica recorded from the Canary Islands (eastern Atlantic Ocean) together with notes on their distribution and ecology. Voucher specimens have been deposited as reference material in the collection of the Instituto Canario de Ciencias Marinas. Seventeen species are listed and seven of them are recorded for the first time for the Canaries: Lepas hilli, Conchoderma virgatum, Xenobalanus globicipitis, Chthamalus sp. (cf. C. proteus), Acasta cyathus, Balanus trigonus and Perforatus perforatus.

Shepherd's beaked whale Tasmacetus shepherdi is one of the most poorly known cetaceans, whose diet has created some speculation given that its dentition differs greatly from that of most other beaked whales that are primarily teuthophagous. The few stomachs examined previously have given seemingly conflicting dietary information. In this paper the stomach contents of a freshly stranded adult female on Tristan da Cunha have been examined through identification of trace elements and genetic analysis of soft parts. At least 13 cephalopod and 8 fish species were identified from beaks and otoliths respectively, but only undigested fish remains were present in the stomach and identified genetically as Beryx splendens. Reconstituted masses totaled 8809 g for cephalopods and 17,554 g for fish, with four species (Histioteuthis atlantica, Taningia danae, Ommastrephes bartrami and Pholidoteuthis ‘A’) comprising 78.6% of the cephalopods and one species (B. splendens) comprising 87.4% of the fish eaten. It is concluded that Tasmacetus may alternately exploit fish and cephalopods, depending on the time of day and access to seamount or continental slope areas.

Suspended organic matter in the oceans has been studied by many authors. In a review of the subject Parsons (1963) states that the occurrence of detritus particles in the oceans seems to be a universal characteristic of sea water. The greatest concentrations of suspended organic matter are to be found in turbulent inshore water masses.

The original descriptions of these two species are discussed and the material mentioned in Smith's description is examined. Discrepancies between Smith's description of Coscinodiscus concinnus and the present interpretation of this species are pointed out. Ways of typifying the two species so as to preserve current usage and still fulfil the requirement of the International Code of Botanical Nomenclature are given. Lectotypes for the two species are designated. Diagnostic characters distinguishing the two species in the living state as well as the cleaned valves are given.

The Marine Biological Association of the United Kingdom, to whom the Plymouth Laboratory belongs, is a corporate body of subscribing members, interested in scientific investigations concerning the habits and life-histories of food fishes and other marine animals. The Laboratory is managed by a Council elected annually by the members of the Association.

The Monstrilloida form an aberrant group of Copepoda, distinguished by the complete lack, in the adults, of gut and mouth-parts. Sars (1921) divided the group into two sections, one being the Monstrilloida Cyclopimorpha, comprising a single family, now called the Thespesiopsyllidae (see Wilson, 1932), with two genera. The larvae of Thespesiopsyllus are gut parasites of ophiuroids (Bresciani & Liitzen, 1962). The second genus, Orientopsyllus, was described by Sewell (1949) from the Indian Ocean.

The second section, the Monstrilloida Genuina, comprises the single family Monstrillidae, various authors (Malaquin, 1901; Sars, 1921; Rose, 1933; Davis, 1949) differing in their division of this into genera. The present author regards the family as consisting of three genera, Monstrilla Dana, 1848, Thaumaleus Kroyer, 1846, and Monstrillopsis Sars, 1921, separated according to the criteria listed in Table 1.

Mesoscale features within the Gulf of Mexico (GOM) are known to influence zooplankton dynamics. Here we describe the composition of the zooplankton assemblage off shelf during summer in relation to environmental conditions, with emphasis on hyperiid amphipods and salps. Zooplankton samples were collected in summer of 2015 and 2016 in the central and southern GOM and in the Yucatan Channel in 2015. Two anticyclonic gyres were present in the north and less intense coupled cyclonic-anticyclonic gyres in the south. Zooplankton abundances differed temporally and spatially. Copepods were the dominant group (>55% of total abundance), while several less abundant taxa contributed to inter-annual and spatial differences. Amphipods and salps comprised <3% and their abundances were positively correlated. Fifty-six hyperiid and 10 salp species were identified. The dominant amphipod species were: Lestrigonus bengalensis (summer 2015), Anchylomera blossevillei and Primno spp. juveniles (summer 2016). Dominant salp species were Ihlea punctata, Iasis cylindrica and Thalia spp. Lower salp and amphipod species richness and abundance were associated with anticyclonic structures. Spatial and temporal differences were partly associated with symbiotic relationships between the groups. This study supports previous evidence of high spatial and temporal variability in zooplankton abundance in off-shelf waters of the GOM.

This study describes species of the genus Hymedesmia from three areas of cold-water coral reef: Mingulay Reef Complex (Scotland, UK) and Rockall and Porcupine Banks (off UK and Irish coasts). Five new species are described: Hymedesmia (Hymedesmia) gibbosa, H. stoneae, H. tendali, H. xavierae and H. valentinae. Records are provided of other poorly known Hymedesmia species: H. bocki, H. cohesibacilla, H. curvichela, H. ebria, H. gustafsoni, H. simillima, H. irregularis, H. proxima, H. hibernica and H. primitiva. Information on distribution of other Hymedesmia species occurring in Britain and Ireland is presented. The sites studied represent a variety of depth-ranges and the data collected suggest that some Hymedesmia species may be restricted to particular bathymetric zones.

The hypothesis investigated in this paper is that the interstitial polychaete Saccocirrus sonomacus is excluded from beaches impacted by tailing disposal as a result of the blocking of the interstitial space and not by a response to the toxicity of elevated copper concentrations. Field evidence suggested that abundances of S. sonomacus on beaches where they would be expected to occur under natural conditions are lower when a beach has received a significant amount of tailings. In choice experiments, S. sonomacus always preferred an open coarse sand matrix to one where the interstitial spaces had been blocked by fine sand (a tailings substitute). Using invitro bioassays, we found that the LC50 for S. sonomacus with copper was 44 μg Cu l−1, this being higher than the values of interstitial labile copper measured on the beaches investigated in this study. We therefore accept the hypothesis of a physically mediated exclusion rather than a toxically mediated one.

Since the incursions of the introduced green macroalgae Codium fragile ssp. tomentosoides and ssp. atlanticum on European shores, the abundance and distribution of the native congeners C. tomentosum and C. vermilara have come under closer scrutiny. Hypotheses regarding the reported declines in the native(s) are largely speculative due to the paucity of quantitative information on the natives, the cryptic nature of the invaders and the unknown processes regulating Codium assemblages. As part of a field-based Codium study on north-eastern Atlantic shores, our surveys on Guernsey shores, Channel Islands, in September 2002 have revealed two unexpected and noteworthy results: (1) thriving populations of C. tomentosum are quite abundant on mid to low littoral shores; and (2) in marked contrast, sparse populations of C. fragile ssp. tomentosoides are restricted primarily to upper mid-littoral rock pools. Native Codium has not been displaced or eliminated from the southern end of the British Isles.

INTRODUCTION

Members of the leucosiid genus Ebalia are typical oxystomatous crabs which live on subtidal coarse sediments at depths ranging from a few metres to over 2500 m. Although this genus has an almost worldwide distribution, no studies of the population biology of any species has been made.

Five species of Ebalia occur round British coasts (Ingle, 1980), four of which have also been recorded from the Clyde Sea area (Allen, 1967). During dredging surveys in this region, a sizeable population of Ebalia tuberosa (Pennant) was located in the vicinity of the University Marine Biological Station on Great Cumbrae Island, and regular sampling of this population over a period of two years provided the data on which this study is based.

Apart from a few references to the occurrence of female crabs in berry (Lebour, 1928a, b; Marine Biological Association, 1957; Allen, 1967) and to the occurrence of larvae in the plankton (Jorgensen, 1923, 1925; Lebour, 19286; 1947; Rees, 1952; Williamson, 1956; Marine Biological Association, 1957; Bruce, Colman & Jones, 1963; Crothers, 1966), no other information on the population biology of E. tuberosa is available.

This paper is the first attempt to study the recruitment of Serpuloideans in a Mediterranean marine cave through the use of artificial substrates placed in three different positions, from the entrance to the interior of the cave. This study provides qualitative and quantitative data concerning Serpuloidea recruitment on panels removed successively after one, three, six and 12 months of permanence in the cave. A homogeneous distribution of juveniles Spirorbidae throughout the cave axis had already been detected after one month of panel immersion. Spirorbids were recorded also on panels removed after three months as well as serpulids, which began to be detected during this sampling time, even though represented by just one species. A significantly different pattern of distribution throughout the cave axis was observed after only six months, while other serpulids were detected for the first time. The pattern of species distribution seemed to reflect the biotic and environmental conditions of the cave. The highest serpuloidean species abundance and diversity was found on panels placed in the intermediate position within the cave. After only one year of panel immersion, a total of 20 taxa (11 Serpulidae and 9 Spirorbidae) was recorded, including five species listed for the first time in the marine caves of the Salento Peninsula.