Molluscan shells showing phenotypic variations are ideal models for studying evolution and plasticity. In north-eastern Asia, genetic and morphological diversity of the gastropod, Monodonta labio, were assumed to be influenced by both palaeoclimatic changes and current ecological factors. In this study, we examined spatial variations in shell shape of M. labio using general measurement and geometric morphometric analysis. We also investigated whether shell shape variation is best explained by environmental gradients or by genetic structuring, based on our prior molecular phylogeographic study. Two common morphological forms were observed among Chinese populations and in the adjacent Asian areas. Both the analyses revealed separation patterns in morphological variations of shell shape among the clades and populations. Environmental modelling analysis showed a significant correlation between shape variations and local maximum temperatures of the warmest month, indicating the role of natural selection in the evolution of this species. Data obtained in this study, combined with the cytochrome oxidase subunit I (COI) molecular phylogenetic data from the prior study, showed that morphological variations in M. labio were constrained by both local adaptation and phenotypic plasticity. We hypothesized that geographic separation by the Dongshan Landbridge was the first step towards its diversification, and that the temperature gradient between the East China Sea and South China Sea probably was the selective force driving the divergence of its morphological variations.

Natural mortality (M) is a key parameter for understanding population dynamics, especially in relation to harvested populations. Direct observations of M in crustaceans are scarce, due to the moulting process. Indirect methods to estimate M with easier-to-obtain life history attributes are therefore used routinely. Given their theoretical background, we reviewed the applicability of these methods for crustaceans. We applied the selected methods to two crustacean species harvested in Chilean waters: the yellow squat lobster (Cervimunida johni) and red squat lobster (Pleuroncodes monodon). Uncertainty of each M estimate was incorporated in the life history parameters that input into the indirect method (trait-error) and parameters defining the indirect method (coefficient-trait-error). Methods based on the relationship between total mortality and maximum age, or with different ages and based on life history theory were the most appropriate for crustaceans since they apply across taxa. M estimates showed high variability between species, sexes and areas. Estimations of M for C. johni varied from 0.13 to 0.28 (year−1) for males and 0.17 to 0.51 (year−1) for females. For P. monodon values for the north varied from 0.26 to 0.37 (year−1) for males and 0.24 to 0.45 (year−1) for females. In the south, values of M were higher for both males (0.43–0.68 year−1) and females (0.41–1.06 year−1). High variability in the M estimates was associated with the method and number of parameters, their uncertainty, theoretical background and probability distribution. M estimates are not comparable, raising the need to propagate the uncertainty of M into the stock assessment of Chilean squat lobsters.

The generic name Ovulina was proposed by Anderson, Rogerson & Hannah (1996) to apply to the type and only species O. parva Anderson et al., 1996 based on laboratory cultured individuals isolated from sediments in the Firth of Clyde, Scotland and type specimen deposited in the British Museum of Natural History (registration number 1995:10:25:2). The name is a junior homonym and therefore invalid. Ovulina was proposed previously for a foraminiferan by Ehrenberg (1854) and used subsequently by Gruber (1884).

Ovulinata nom. nov. is proposed here as a replacement name for Ovulina Anderson, Rogerson & Hannah, 1996. The name signifies the ovoid shape of the test and the ovulate cell body as described in the original diagnosis and etymology (Anderson et al., 1996).

Amphipod traps baited with crab carrion caught significantly greater numbers of the specialist crab necrophage, Orchomene nanus in the South Basin of Lough Hyne than in the North Basin. The results can be explained with reference to the known distribution of crab species in the lough and also the hydrographical characteristics of the two basins.

Although the distribution of most coastal and oceanic fishes of the seas of northern Europe is relatively well-known extensions to known range are reported with moderate frequency as vagrant specimens are found or captured and recorded. Possibly it is partly because the fish fauna is well documented, with reliable literature to permit identification, that rare or unusual fishes are quickly recognized and attempts made to identify them. Most such specimens are housed in museum or other institutional collections and thus information about them can be retrieved long after their capture. However, the circumstances of the present report which records the stranding of a white marlin T. albidus Poey, 1860 on the Lancashire coast at Morecambe Bay are somewhat unusual in that the whole specimen was eaten and the only evidence remaining are two photographs and a small piece of skin. In view of the interest of this occurrence, which represents a northward extension of the range of the species by several hundred miles, as well as the first report of its occurrence in British seas, full documentation is given here and both available photographs are reproduced.

In a study of the age and growth of Platycephalus indicus, a total of 1106 fish were collected from May 2011 to March 2012 in the coastal waters of Iran, Persian Gulf. The ages of 279 specimens were determined by sectioned otoliths. The ages of the females were estimated to be between 0+ to 7+ , while the ages of the males were from 0+ to 4+. The von Bertalanffy growth curve was well suited to the age/total length data of males and females as follows: Lt = 43.40{1–exp[−0.45(t + 0.328)]} for males, and Lt = 63 {1–exp[−0.50(t + 0.30)]} for females. linf = 43.40, k = 0.45, t0 = −0.328 for females and linf = 63, k = 0.50, t0 = −0.30 for males. The estimated values of natural mortality (M) were M = 0.886 yr−1 for females and 0.736 yr−1 for males, and the estimated Z values were 1.43 yr−1 for females and 1.62 yr−1 for males. The mean value of the gonadosomatic index for males and females was 0.82 ± 0.25 and 2.48 ± 0.59, respectively, in each year. The mean values of the hepatosomatic index (HSI) were 0.89 ± 0.20 for males and 1.28 ± 0.16 for females. The highest HSI values for this location were observed in January, and the lowest were in April.

Biometric relationships of size and weight were estimated for the Argentinean prawn (Artemesia longinaris), a new commercial penaeid prawn exploited in the south-western Atlantic. Morphometric and meristic traits were used to elucidate population structure of this species along its distribution area. The morphological relationships were estimated by a simple linear regression, considering total length (TL) as the dependent variable. The males collected in southern Brazil, an area under influence of the Subtropical Convergence, presented a slightly lower TL increment than females. A marked reduction in slopes of males between populations from southern Brazil was observed in autumn and winter. Additionally, relative growth in length of males from Argentina is similar to that observed during autumn and winter in southern Brazil. The other morphometric and meristic variables used also indicated higher similarities between southern Brazil and Argentina, which may be explained by relative growth associated to water temperatures or migration during winter, taking advantage of the oceanographic systems connecting both sites. Moreover, the population from Rio de Janeiro seems morphologically apart from the others, forming a separate unit stock.

Benthic habitat and epibenthic megafauna are described from seabed photographs taken in or near three potential deep-water Marine Protected Areas on the Hebridean Slope, surveyed in 1988, 1995–96 and 1998. Broad bathymetric zones are defined by visible substratum characteristics, and by cluster analysis using presence/absence of identified fauna. The shelf edge and upper slope (to 350 m depth) showed current-swept coarse substrata with a very sparse fauna. A transition to finer sandy sediments was apparent at 350–470 m, with a greater abundance of mobile epifauna. The brittlestar Ophiocten gracilis occurred at high density below 600 m depth in all three areas. Southern stations indicated an abrupt lower boundary for this zone at ca 1000 m. In the north, rippled sands with xenophyophores occurred below the O. gracilis zone at 1000–1100 m. Xenophyophores were also seen in smaller numbers at this depth in the south. From ~1300–1600 m a seabed of burrowed fine mud was recorded in both northern and southern areas. Bioturbated sediments on the Rockall Trough floor at ~2060 m supported more visible epifauna, principally the brittlestar Ophiomusium lymani and the octocoral Acanella arbuscula. The bathymetric pattern differs from a scheme proposed in 2010 for the deep north-east Atlantic in the lack of any obvious zonal boundary at 750 m. No cold-water corals or sponge aggregations were observed. Trawl marks were observed in all three areas, particularly in the 1998 northern survey, with highest frequency at 1300–1400 m.

The genus Acanthogobius of gobiioid fish has been reported for six species from East Asia, and inhabits estuarine and coastal waters. Within this genus, Acanthogobius insularis is an endangered and endemic goby in the Amami-oshima and Okinawa-jima Islands, southern Japan, and its range is restricted to the lowermost course of a few river basins. Basic knowledge on this species is scarce in spite of its vulnerable conservation status. The purpose of this study was to elucidate the life history of A. insularis. Monthly sampling was conducted at five stations in the Taiho River, Okinawa-jima Island, from November 2014 to November 2015. Monthly standard length (SL) distributions were unimodal except in April during the recruiting period, suggesting that A. insularis is an annual species. Analysis of the gonadosomatic index and histological observations of the ovaries revealed that this species spawns from January to May. The beginning of the spawning season seems to be related to a decline in water temperature in December. Growth rates appeared to be lower from April to December and higher in winter months. From monthly collections, A. insularis was found to move upstream with growth, and gather at spawning grounds during the reproductive season. Acanthogobius insularis might be threatened by increasing water temperature due to climate change, since low water temperatures appear to be important for their reproduction and growth. Moreover, habitat diversity, from tidal flats for recruiting grounds to upstream sites with cobbles for spawning, is needed to complete their life cycle, and should be conserved.

This study examines global zoogeographic patterns of estuary-associated fishes using meta-assemblages compiled at the marine ecoregion scale. The classification of biogeographic regions based on estuary-associated fish species is assessed in relation to marine and freshwater zoogeographic patterns. Historical (palaeobiogeographic) and contemporary environmental factors that contribute to the establishment and maintenance of these regions are also discussed. Global patterns in estuary-associated fish species richness demonstrated that tropical ecoregions are more diverse and richer in species than temperate ecoregions; the tropical Indo-Pacific and the tropical western Atlantic were two major centres of high global species richness. Multivariate analyses identified several ecoregion groupings that broadly corresponded with both freshwater and marine biogeographic regions. These groupings could also be related to global marine palaeobiogeographic processes such as the closure of the Tethys Sea linkage during the Cenozoic as well as contemporary factors such ocean currents, upwelling areas and climatic factors, particularly rainfall and runoff.

Protozoan communities at three beaches on the Cantabrian Sea were studied. Four stations along a transect of 150 m at each beach were chosen for this study. The following parameters were measured: temperature, pH, oxidation–reduction potential, dissolved oxygen, conductivity, salinity, nitrate, phosphate, granulometry and amount of organic matter. Four groups of protozoa (ciliates, non-dinoflagellate flagellates, dinoflagellates and sarcodines) were analysed for their abundance and diversity, as well as the influence of the measured parameters on the communities. Temperature, pH, and dissolved oxygen were the main factors responsible for seasonal differences. Temperature increased at the beginning of spring and summer, coinciding with growth of the protozoan community. Flagellates and dinoflagellates increased during spring and early summer. The amount of organic matter subsequently rose. The final step of this succession was the development of the ciliate community. A comparison between the same areas in 1989 and in the present study was carried out.

Reproduction, diet and growth of silky shark Carcharhinus falciformis in the eastern Arabian Sea are described based on 473 specimens collected from the gillnet-cum-longline landings at the Cochin fisheries harbour during 2012–2014. The reproductive biology of 215 males and 258 females was examined while 113 stomachs were sampled to study the diet. The von Bertalanffy growth parameters estimated using length-based models were asymptotic length (L ∞) = 309.80 cm, growth coefficient (K) = 0.10 year−1 and age at zero length (t 0) = −2.398 year. The sex ratio was significantly skewed to females. Seasonality in reproduction was not evident and in males, sexual maturity was attained at 201–223 cm total length (L T) with the size at maturity (L T50) occurring at 217.0 cm, whereas in females sexual maturity was attained at 224–231 cm L T and L T50 occurs at 226.5 cm. In total 114 embryos, in the length range of 12.2–65.1 cm were recovered from 15 pregnant females. Numbers of embryos in females were in the range of 3–13, averaging 7.6. Silky sharks of the eastern Arabian Sea feed primarily on swimming crab Charybdis smithii, with juveniles feeding principally on swimming crabs, while adults feed on actively swimming prey like squids and teleost fishes. This preliminary information on the reproduction, diet and growth should be useful to identify management strategies for silky sharks in the eastern Arabian Sea.

The presence of potentially toxic elements (PTE) was determined in different tissues of five selected marine organisms. The As, Cd, Cu, Mn, Mo, Ni, Pb and Zn concentrations were measured in the seagrass Cymodocea nodosa, the green alga Cladophora echinus, the red alga Gelidiella lubrica, the marine topshell Phorcus turbinatus and the littoral crab Carcinus aestuarii, as well as in seawater from Makirina Bay. The levels of As, Cd, Cu, Mn and Zn in the biota were found to exceed those in previously analysed sediments, indicating the bioaccumulation of these PTE. The biota-sediment accumulation factor (BSAF) and concentration factor (CF) varied among different organisms. As regards the five selected species, C. nodosa, C. echinus and G. lubrica proved to be the strongest accumulators of Mn, while P. turbinatus and C. aestuarii showed a high capacity to accumulate As, Cd, Cu and Zn. These species can be considered as good ecological indicators in the assessment of PTE pollution in marine littoral environments.

Baited trap or pot fisheries are considered to have relatively few wider ecosystem effects on the marine environment, particularly when compared with towed mobile fishing gear. However, this assumption is rarely tested in the field. This study aimed to determine the composition of non-target species that occur in crustacean pots and to assess spatial and temporal differences in catches in the waters around the Isle of Man, Irish Sea. The data were collected using fishery independent surveys and a questionnaire study. Based on fishery independent surveys, a total of five taxonomic groups and 43 species occurred as by-catch. The dominant by-catch species was velvet crab Necora puber. The by-catch per unit effort (BPUE) for all of the non-target species was low particularly in comparison to towed bottom gear fisheries around the Isle of Man. BPUE of species composition varied considerably between different locations around the Isle of Man. The results of both the fishery independent and questionnaire data suggested that the by-catch rates varied with season with peak BPUE occurring in spring which then declined into autumn and winter. By-catch composition did not decrease significantly with an increasing target species catch. Overall, by-catch was low relative to target species catch which may be partially attributable to the use of escape panels in pot fisheries in the Isle of Man.

The sphaeromatid crustacean isopod genus Campecopea is revised, a new diagnosis given and the genus Anoplocopea Racovitza, 1907, is placed in synonymy; the type species Campecopea hirsuta is redescribed and Campecopea lusitanica comb. nov. is recorded from the Canary Islands and Azores. The four species of Campecopea differ from each other principally in the presence or absence of a prominent posteriorly directed dorsal process on the male pereonite 6, the ornamentation of the posterior pereonites, the shape of the uropods and also the fine details of the dactylus accessory spine (smooth or serrate).  The phylogenetic significance of dorsal process is re-evaluated here, and the character discussed in relation to Campecopea, Dynoides and Clianella, and several other sphaeromatid genera. It is regarded that the interpretation of this character as being of intrinsic generic merit has resulted in the over splitting of several genera and also the creation of paraphyletic genera. It is suggested that reappraisal of sphaeromatid generic characters in cladistic terms is a necessary first step in terms of establishing the monophyly of many sphaeromatid genera.

Calcareous green alga in the genus Halimeda are important contributors to the marine carbonate budget. Dongsha Island is located in the northernmost South China Sea and is a seagrass-dominated ecosystem with intermixed Halimeda macroloba patches, making it an excellent system to better examine the extent of carbonate contribution by H. macroloba in such an ecosystem. To this end, we examined the standing stock and actual CaCO3 contribution of H. macroloba in the seagrass-dominated ecosystem (herein Dongsha Island) and compared them with those in Halimeda-dominated ecosystems. The density, growth rate, calcification rate and CaCO3 content of H. macroloba at four life stages were investigated. The mean density of H. macroloba was around 8.82 ± 1.57 thalli m−2 and the estimated standing stock was 61,740 to 72,730 thalli. Thalli produced 1 to 2 new segments day−1, giving a growth rate of 0.003 ± 0.001 g dry weight thallus−1 day−1. Calculated algal biomass and annual areal production were 0.03 g m−2 and 9.66 g m−2 year−1. In each square metre of this area, H. macroloba produced 8.82 to 17.64 new segments day−1, accumulating 0.002 ± 0.001 g CaCO3 thallus−1 day−1 or around 6.44 g CaCO3 m−2 year−1. Mean CaCO3 content was 0.32 ± 0.05 g thallus−1. As expected, the growth rate and CaCO3 production of H. macroloba in Dongsha Island were lower than in other studies from Halimeda tropical ecosystems. Overall, this work provides the baseline of carbonate production of H. macroloba in Dongsha Island and relevant systems where the ecosystem is dominated by seagrasses.

The spatfall in 1924, as in 1923, was very slight and from the point of view of the oyster-producer was a failure, and was little better in 1922.

The growth of oysters in the summer of 1924 was unusually great; this has had the effect of bringing a large proportion of small oysters to a legally takeable size.

The dredging results have, therefore, been much better than they were expected to be in the season of 1924–25, but the effect has been to deplete the beds still more of reserve stocks of small.

Practically all the present stocks of small oysters are of a size between 2 and 2½ inches.

With only average growth in 1925 and 1926 a large majority of these small oysters will have attained a size which will not pass through a 2½-inch ring; hence the beds are in a dangerous state.

If, therefore, dredging continues under the present conditions, almost the whole of the present stock of small will have grown to large oysters and be cleared off the beds in the season of 1926–27.

It is shown that although oysters may grow to a size of 2½ inches at Falmouth in small numbers in three summers, yet four summers are required before a fair proportion of spat can be expected to attain a size of 2½ inches.

The taxonomy and distribution of sipunculan species in the shallow-water zone (< 200 m depth) of European seas are fairly well-documented. One notable exception is Phascolosoma intermedium, a small-sized species described by Southern (1913 a) from material dredged off the west coast of Ireland at 44–143 m depth. Since its description, no further specimens of P. intermedium have been reported in the region and the species was not considered by Stephen (1960) in his synopsis of the British species.

The rhabdocoele turbellarian Paravortex scrobiculariae (Graff) was first described, but not named, by Villot (1878) who discovered this parasite living in the gut of Abra tennis (Montagu) in Brittany. In naming the species, Graff (1882) did not add to Villot's description. Wahl (1906) erected the genus Paravortex to include this form which he had found in Scrobicularia plana (da Costa) and Venerupis decussata (L.) at Trieste and Naples. The first record of P. scrobiculariae in British waters was supplied by Freeman (1957) who, working at Whitstable, Kent, found 8 specimens in 3 out of a sample of 40 S. plana he examined. No further British record appears to have been made.

A recent survey has shown Paravortex to be common and widespread in S. plana inhabiting the estuaries of south-west England. As noted by previous workers, Paravortex can be readily seen through the semi-transparent gut wall of its host on account of its pinkish colour; observation is facilitated if the bivalve is maintained in clean sea water for 3–4 days to allow evacuation of some of the gut contents and is most easily performed during the winter months when gametes are not present in quantity. In this study, counts of the Paravortex were made by removing the gut from the surrounding foot tissues and releasing the Paravortex by cutting the gut longitudinally. From each locality, 20–30 S. plana, all within the length range of 30–50 mm, were examined. Paravortex is viviparous, the newly-hatched young being 120–150 μm long; at this stage they are transparent and are easily overlooked amongst the gut contents; thus counts relate chiefly to adults 0·5–1·5 mm in length.

Activities of phosphomonoesterases were measured at acid and at alkaline reaction (pH 4–5 or 9–65) in homogenates of elasmobranch tissues especially lymphomyeloid structures. The animals were dogfish (Scyliorhinus caniculd) and two species of ray (Raja brachyura, R. naevus). Acid phosphatase activity was high in the epigonal tissue, Leydig's organ, the spleen and the thymus. High activity was also found in the pancreas and the kidney, whereas skeletal and cardiac muscle showed low values. The activity of alkaline phosphatase was very high in the kidney and relatively low in other tissues. Ultrasonification of homogenates from the dogfish resulted in increase of acid phosphatase activity but had little effect on alkaline phosphatase activity. The high activity of acid phosphatase in lymphomyeloid tissue may be due to the presence of large numbers of various types of leucocytes.