The salinity tolerance of herring 9-ca 24 cm in length was found to lie between 6‰0 and 40–45‰0.

Determinations of changes in weight and blood concentration (by measurement of the freezing-point), when herring were transferred from one salinity to another, demonstrated that extensive changes occurred in the blood. Under these conditions the herring experienced and survived blood concentrations equivalent to salinites of 13–22·5‰. A recovery to near normal (δ0·95 ≡ 15·8‰) took place in all the salinities within the tolerance range.

Badly descaled herring in sea water showed large increases in blood concentration before death.

A study of the kidney of the herring indicated that the ability to withstand the low salinities for long periods probably rested in the high glomerular count of the kidney.

The importance of damage to the skin for survival is discussed in relation to tagging experiments.

The results are also discussed in relation to the evolution of the herring.

Few observations on living pterobranch hemichordates have been published. Gilchrist (1915) and Andersson (1907) have observed living zooids of Cephalodiscus; while Sars (1874), Schepotieff (1907) and Burdon-Jones (1954, 1957) have observed living Rhabdopleura. No observations appear to have been published on living Atubaria. Recently R. compacta Hincks was discovered near the Plymouth Laboratory (Stebbing, 1968) and during our work (Dilly, 1971, 1972a, b; Stebbing, 1970a, b) we have made some observations on living specimens. Attempts to keep R. compacta alive for long periods have not been completely successful (Stebbing, 1970), although Burdon-Jones (1954) managed to study the salinity tolerances of/?, normani Allman for more than 2 months in the laboratory. He has also studied feeding behaviour in living zooids (Burdon-Jones, 1957) Our observations have been made on specimens maintained in recirculation systems over periods of up to 12 weeks.

The anatomy of some members of the family Calyptraeidae has been adequately described by previous workers (Kleinsteuber, 1913; Giese, 1915; Moritz, 1938), and aconsiderable amount of information has been published on the feeding and the unusual reproductive activities of Crepidula (Orton, 1912; Coe, 1944) Of the anatomy and way of living of the members of those other families of gastropods (Trichotropidae and Capulidae) that Thiele (1929) has unitedwith the calyptraeids in his Stirps Calyptraeacea, much less is known. Orton (1912) and Yonge (1938) have described the feeding mechanism of Capulus ungaricus; and the anatomy of Thyca, a parasitic member of the same family, has been briefly described by Koehler & Vaney (1912). Nothing seems to be known of the anatomy or way of life of members of the Trichotropidae. Yet an investigation of some of these points seems overdue in the lightof Lebour's discovery (1937) that Capulus passes through an echinospira larval stage. This stage does not occur in other members of the Calyptraeacea, although present in two other groups of the mesogastropods, the Lamellariacea and the Cypraeacea. The idea at once presents itself that the capulids may perhaps be more accurately classified as members of one or other of these two groups rather than as members of the Calyptraeacea. The work recorded in the following pages was directed towards answering this question, and would suggest that the original classification is the more correct. The names used are those of Winckworth (1932).

Age, growth and maturation of the temperate ‘mini-maximalist’ Idiosepius notoides from Tasmania is described and compared with those of its tropical congener Idiosepius pygmaeus. Using statolith increment analysis, growth of I. notoides was best described by a power curve with a maximum age of 115 days recorded. Males have a shorter lifespan than females, however growth rates were similar between the sexes. Idiosepius notoides grows to a larger size than its tropical counterpart. Onset of maturity in I. notoides occurred at an age of approximately 68 days for males and 88 days for females compared to 45–60 days for I. pygmaeus. Size at onset of sexual maturity was analogous between the two species, with males mature at approximately 6·5 mm mantle length (ML) and females at 14·0 mm ML. Idiosepius notoides, like I. pygmaeus, is a small short-lived sepioid with significant gender dimorphism and the capacity to spawn multiple times throughout its short life. This research supports the concept of similar cephalopod species living longer and growing larger in cooler environments.

This ultrastructural investigation of gametogenesis in a deep-sea anemone of the Bay of Biscay trawled around 2000 m depth, contributes to the knowledge of biology and strategy of reproduction of deep-sea benthos.

This sea anemone is dioecious. The sperm appears very similar to those of shallow water sea anemones of the genus, Calliactis. The ultrastructural investigation of oogenesis allows the characteristics of the stages of previtellogenesis and vitellogenesis to be defined. The latter begins with a period of lipogenesis correlated with the formation of a trophonema. Mature oocytes measure up to 180 (im in diameter. Study of spermatogenesis and oogenesis reveals that spawning occurs in April/May. In males, the main area of testicular cysts, full of sperm, reaches maximal development from March to May and, in females, the percentage of mature oocytes decreases from 33% in April to 1% in May.

Spawning may be induced by the advent in the deep-sea of the products of the spring phytoplankton bloom. This period of spawning, during the increased deposition of organic matter to the deep-sea floor, may be an advantageous strategy for early development of Paracalliactis.

The annual reproductive and somatic cycles of the brittlestar Acrocnida brachiata are described using gonad and gut indices for intertidal and subtidal populations in the Bay of Douarnenez, France. Oocyte size frequency diagrams complement the gonad study in the subtidal population. Clearly marked reproductive cycles are defined in both populations. Accelerated gonad growth takes place in spring and the gonads reach the peak of development in May-June each year. Spawning is completed by the end of August. Oocytes reach a mean diameter of 150 μm and a new generation of oocytes appaears in the ovaries during the spawning period. The gut indices show a clear inverse relationship with the gonad indices in the intertidal population, but this relation is not well revealed in the subtidal population.

Large catches of the snake blenny, Lumpenus lampretaeformis, have been made in the inshore waters of the west coast of Scotland. Analysis of these catches confirm the view that this species shows marked seasonal variations in abundance. The species lives for up to 9 years and has a rapid growth rate in the first 2 years. It feeds mainly on meiobenthic organisms, of which polychaetes, harpacticoid copepods, ostracods and nematodes are the most important. The reason for the seasonal variation in catch rate is discussed and it is speculated that it may result from the fossorial habit of the adults and the parental care of the eggs.

In a previous paper (Armstrong & Atkins, 1950), 201. samples from International Hydrographic Station England No. 1 (EI), about 10 miles south-west of the Eddystone in the English Channel, were filtered through collodion membranes of 1.09μ average pore diameter (A.P.D.).

Between June 1948 and November 1949 the residue from these surface samples, when dried and ignited, amounted to 0.45–2.77 g/m3 (or parts per million). These deposits consisted of 55–17 % silica, 28–3 % ferric oxide, 20 to under 1 % of alumina, and 70 (or, excluding one high value, 29) to 9 % calcium carbonate. A few determinations of insoluble organic matter gave to 1.15–1.77 p.p.m. when dried at 100° C. Pettersson (1934 b), using the glass niters of Schott (Jena), found 1.4 p.p.m. for the total organic and inorganic matter similarly dried, from surface water in the Gullmar Fjord during the spring outburst.

Using Irish strandings data collected between 2002 and 2014, seasonal and annual trends in the number of strandings for all strandings identified to species level (N = 1480), and for the five most frequently reported species: common dolphin (25.7% of records), harbour porpoise (22.2%), long-finned pilot whale (8.8%), striped dolphin (6.9%) and bottlenose dolphin (6.9%) were investigated. With the exception of bottlenose dolphins, there was a significant linear increase in the number of strandings across years for all species and for all strandings collectively, that were identified to species-level. Only common dolphins demonstrated a significant increase in the proportion of records relative to all other strandings, which may be indicative of a real rise in the number of strandings of this species. Common dolphins and harbour porpoises showed a similar significant difference in monthly strandings, with more strandings occurring during the earlier months of the year. Significant differences in the gender of stranded animals were found in common, striped, bottlenose and Atlantic white-sided dolphins and sperm and pygmy sperm whales. Live and mass stranding events were primarily comprised of pelagic species. Most strandings occurred on the south and west coasts, with two hotspots for live and mass strandings identified. The patterns and trends identified are discussed in relation to the caveats in interpreting strandings data. Specifically to Ireland, the findings highlight the urgent need to build on the current volunteer reporting network and augment this comprehensive dataset with post-mortem examinations to better understand the cause of the trends identified. The importance of strandings data in informing conservation and management guidelines of these species’ is discussed.

Several crab species are important fishery resources in Brazil and their overexploitation has lead to severe population declines in some regions. The management of populations of these species should take into account the degree of gene flow among populations in different estuaries. The goal of the present study is to assess the degree of geographical structure in the genetic diversity of the blue land crab, Cardisoma guanhumi, along the Brazilian coast. A fragment of the control region of the mtDNA (750 bp) was sequenced for 95 specimens collected across 5 Brazilian states. Analyses using F-statistics failed to indicate any evidence of geographical structure, a result that was corroborated by a nested clade analysis of the same dataset. Mismatch distribution analyses indicated that populations of the blue land crab have experienced an expansion during their recent evolutionary past. The obtained results are similar to those recently described for another sympatric crab, Ucides cordatus, particularly with respect to the extensive degree of gene flow. However, populations of C. guanhumi seem to be older than those of U. cordatus and do not show the north–south expansion found in that species.

Coastal ecosystems are particularly vulnerable to alien invasions. Regular, standardized, targeted monitoring of coastal areas helps to detect the arrival of non-native species early, identify sites most vulnerable to invasion, and assess potential for further spread. This study quantified the spread and changes in distribution of non-native oyster, Crassostrea gigas, populations around the coast of Ireland. In total 37 sites were surveyed, in areas which either currently or previously harboured cultivated C. gigas, for the presence and abundance of ‘wild’ C. gigas. Wild populations were identified at 20 sites and at four additional sites C. gigas was observed as recently discarded from aquaculture activity. Five of the invaded sites were identified as being highly suitable for a population expansion based on their current population status. Importantly, we also identified individuals of C. gigas and native European oysters, Ostrea edulis, co-occurring within the same shore at five sites. This is the first record to our knowledge of such co-occurrence within Europe. This evidence of co-existing oyster species raises concerns regarding the potential impact of C. gigas on recovering O. edulis populations. In Ireland, however, C. gigas does not typically spread extensively from introduction points, and although self-containing populations exist, they are currently sustained at a much lower density than those observed in other regions such as the Wadden Sea or French Atlantic coasts. We suggest, therefore, that to protect native oyster populations, C. gigas should be eradicated where co-occurring with O. edulis and recommend continuous monitoring of invaded sites.

Latreutes pymoeus is a poorly studied tropical and sub-tropical shrimp species that mainly lives on sea grass beds. Samples were collected from sea grass beds of Inhaca Island, Mozambique, during August 2005 at neap/spring and low/high tides. Specimens were identified, sexed, counted and morphometric measurements were made. Ovigerous females were classified as small (carapace length (CL): 2.7–3.2 mm), medium (CL: 3.3–3.8 mm) and large (CL: 3.9–4.4 mm). Embryo masses were carefully removed from the pleopods with forceps, eggs staged and counted. On average, about 20% more males were found than females (0.64 ±0.25 and 0.56 ±0.28 ind m-2, respectively), but males were significantly smaller (2.25 ±0.32 and 2.60 ±0.47 mm CL for males and females, respectively). At 3.1 mm CL at least 50% of the females found carried embryos in the pleopods. Average (±SD) brood size increased significantly with female length (76 ±18, 133 ±64 and 205 ±61, for small, medium and large ovigerous females). The number of embryos decreased significantly over the incubation period for each size-class of the shrimp. Brood loss from embryonic Stage I to Stage IV for small, medium and large shrimp were 19.8%, 36.5% and 41.8%, respectively. Although an increase in brood loss was observed with increasing shrimp size, senescence did not seem to occur since larger shrimps carried a higher number of embryos and negative allometry was not recorded. Mean embryo volume, in the same development stage, was not significantly different among the small, medium and large shrimp, increasing significantly from 0.014 mm3 to 0.029 mm3 from the first to last embryonic stages.

The taxonomy of the snapping shrimp Alpheus cristulifrons Rathbun, 1900, previously reported from the eastern Pacific and western and eastern Atlantic, is reviewed based on molecular data (COI), morphology and colour patterns. Three species are recognized in the A. cristulifrons species complex. Alpheus cristulifrons sensu stricto is restricted to the western Atlantic, ranging from Florida and the Caribbean Sea to southern Brazil. The eastern Pacific A. cristulifrons sensu Kim & Abele, 1988 corresponds to A. utriensis Ramos & Von Prahl, 1989, ranging from the Gulf of California to Colombia; this species can be separated from A. cristulifrons by the absence of balaeniceps setae on the male minor chela and the presence of bands on the antennular and antennal flagella. The eastern Atlantic A. cristulifronssensu Crosnier & Forest, 1966 is described as A. xanthocarpus sp. nov. based on recently collected material from the island of São Tomé in the Gulf of Guinea; this species differs from A. cristulifrons by the posteriorly more extending rostral carina and the presence of conspicuous yellow spots on the carpus and chela of the second pereiopod. Molecular data suggest that A. utriensis is the eastern Pacific sister clade to the amphi-Atlntic clade that includes A. cristulifrons and A. xanthocarpus sp. nov.

The general biology of the common starfish, Asterias rubens L., has recently been studied by Vevers (1949), whose investigations included observations on the growth-rate of this species. His material was collected in the Plymouth area largely by means of an otter trawl, supplemented by a few Agassiz and dredge hauls, and there are therefore few records in his data of the growth-rate of juvenile A. rubens under natural conditions. Vevers also made observations on the growth-rate of individuals kept in laboratory tanks, but again the results apply mainly to fairly large animals. The only other direct observations on growth-rate appear to be those of Bull (1934), who dealt with three small individuals kept in aquarium tanks, while Orton & Fraser (1930) give measurements made on a natural population taken, after one year's growth, from a buoy.

Annual gametogenic cycle in ocean quahog, Arctica islandica, was investigated using specimens collected regularly from a near shore population in north-western Iceland from December 1997 to November 1998. Gonads from 450 adult quahogs with shell length ranging from 65 to 106 mm were examined after being prepared by standard histological techniques. Observed gametogenic progression was categorized by five phases: (EA) early active; (LA) late active; (R) ripe; (PS) partially spent; (S) spent. All phases of the gametogenic cycle were present in the samples all the year around except in May and June when no spent individuals were seen, and in June and July when no individuals in the early active phase were observed. Morphologically ripe specimens predominated in the samples from May until August when partially spawned individuals dominated the population and did so until February. Spawning activity as inferred from the histological examination appears to be all the year around but most intense from June until August.

Fisheries by-catch is considered to be a major threat to loggerhead turtles in the Mediterranean Sea. Technical differences in both gear configurations (e.g. hook and bait type) and fisheries operations carried out by the Spanish Mediterranean surface longline fleet could have an effect on by-catch rates and size selectivity. The aim of the present study was to test the differences in by-catch per unit effort and body size of loggerhead sea turtles caught using different gear types in the Mediterranean surface longline fishery. Our results suggest that differences in the gear type used have an effect on catch rates and size selectivity. Thus, surface longliners targeting albacore (LLALB) using smaller hooks tend to capture smaller loggerheads but have the highest by-catch per unit of effort (BPUE), whereas other longlines, such as surface longliners targeting bluefin tuna (LLJAP) and traditional surface longliners targeting swordfish (LLHB), using larger hooks tend to select the larger animals; moreover, LLHB had the lowest BPUE. Disproportionate rates of fisheries-induced mortality on certain size/age-classes can differentially affect sea turtle populations, as each sea turtle age-class contributes differently to current and future reproduction. Thus, fisheries management should not only be focusing on preserving the large juvenile and mature turtles, but also on reducing the total by-catch. Thus, we recommend encouraging the use of LLHB versus other surface gears. We suggest that it is very important to take into account the gear type (and its particular catch rates) when making inferences about the impact of longline fisheries on sea turtle populations.

Factor analyses have been carried out on the total data for 134 planktonic forms sampled during the 1965 SOND cruise by R.R.S. ‘Discovery’. Species assemblages are largely consistent with the intragroup analyses carried out previously (Angel & Fasham, 1973). Factor score plots for the separate day and night series confirm the rather limited number of categories of vertical distribution patterns that occur despite the occurrence of vertical migration. The analysis of the combined day and night data confirms the rather limited number of patterns of vertical migratory behaviour. Size spectra of euphausiids in some of the assemblages associated with each category suggest that there may be resource partitioning. The trophic relationships within the assemblages appear to be structured and are discussed in the light of the limited knowledge of the feeding behaviour of many of the species involved. Diurnal vertical migration behaviour in planktonic species appears to be limited to the top 700 m.

A Galway Bay population of the dragonet Callionymus lyra (L.) was investigated between March 1978 and November 1979. Monthly collections were made on board commercial fishing vessels. A total of 3302 fish was examined. The male to female sex ratio in the catch was 1·14:1 and it departed significantly from a 1:1 ratio. Males grew significantly faster than females, when measured by length and by weight, and attained a greater maximum length, but females had a longer life span. Females were significantly heavier than males for any body length. The spawning season was protracted, lasting from January to August and peaking during February-April. Callionymus lyra is a carnivore, feeding mainly on polychaetes and crustaceans, but molluscs and echinoderms were also eaten in abundance. A yearly cycle in feeding intensity was observed, showing reduced feeding during the colder months. The feeding index expressed as gut weight / body weight was significantly higher for females.

Himanthalia elongata (=H. lorea (L.) Lyngb.), although a common brown seaweed on parts of the British coast, does not occur in sufficient quantities to render it of commercial importance. As a result, the work of Colin & Ricard (1930) appears to be the only investigation on the chemical composition of this species. Their material was collected in August 1929, but they give no indication of the size or condition of the plants which were analysed.

The life-histories of the erycinaceans Montacuta substriata and M. ferruginosa were investigated with special reference to the initiation of their ‘commensal’ associations. The planktotrophic larvae are released in summer as veligers after incubation within the adults, and they may spend several months in the plankton before settlement and metamorphosis. Larvae of both species, isolated from the Plymouth plankton, were reared to post-larval stages that were comparable with spat found associated with spatangoids. Some corrections are made of the identifications of planktonic larvae, of these and other Erycinacea, by previous authors. Experiments showed that, apart from being more active, the responses of walking post-larvae are similar to those I have described previously with adults. It is considered that the reactions operate, in an integrated manner similar to the adults, in initiating their associations with spatangoids; the behaviour of the adults in maintaining and re-establishing their associations would thus represent a retention of larval faculties. Possible reasons for the restriction of M. substriata to superficial burrowers and the less specific occurrences of small M. ferruginosa amongst spatangoids—including both deep and shallow-burrowing species—are discussed.