bluuebunny/crossref_metadata_2025_split huggingface dataset:
The grouping of herring populations
Authors: Cushing D. H. 
Published: May 2009

The work of Colebrook & Robinson (1965) has shown that there are three groups of seasonal cycle in production in the north-east Atlantic. There are three ‘races’ of herring in the same area, spawning in autumn, winter and spring. Taking the dates of spawning of each ‘race’ and the date by which the larvae must have food, a connexion can be made between the herring race and the production cycle in the area in which it lives. It is assumed that the date of spawning is fixed and does not vary with environmental conditions. Once the connexion between herring race and production cycle is made, certain comparisons can be made between races in growth rate, reproductive capacity and in the variability of recruitment. It was tentatively concluded that the magnitude of the year-class in the three north-east Atlantic races must be determined before metamorphosis. After metamorphosis, herring live on the beaches where the production cycle must have quite a different character.IntroductionHerring populations have been grouped as spring and autumn spawners ever since they have been examined scientifically. Autumn spawners have been further subdivided into early autumn (or summer) and late autumn (or winter) spawners (Johansen 1924). Since the discovery of sharp differences in fecundity and egg size between early and late autumn spav/ners (Polder & Zijlstra, 1959), the distinction between them has acquired the same status as that between autumn spawners and spring spawners. However, there are very marked differences between all three groups, and to relate them to then-calendar times of spawning it is proposed to name then ‘ autumn’ (formerly early autumn), ‘winter’ (formerly late autumn) and ‘spring’ spawners.
Phorbol Ester-Induced Metamorphosis in the Parasitic Barnacle,Loxothylacus Panopaei
Authors: Glenner Henrik , Brodin Birger 
Published: May 2009

In order to induce metamorphosis in cyprids of the parasitic barnacle Loxothylacus panopaei (Gissler) (Cirripedia: Rhizocephala: Kentrogonida), we tested a number of compounds (ZR-512, 20-hydroxyecdysone, 3-isobutyl-l-methylxanthine and phorbol-12,13- dibutyrate) all known to cause metamorphosis in thoracican barnacles. Only one agent, phorbol-12,13-dibutyrate, had an effect and induced cypris larvae to complete metamorphosis without previous attachment. This suggests that diacylglycerol-activated protein kinase C plays a role in the metamorphosis of kentrogonid rhizocephalans.Rhizocephalans are highly specialized crustaceans adapted for parasitic life on decapods. The juvenile parasite passes through an internal growth stage, where a root-like trophic organ invades the tissue and haemocoelic fluid of the host (for detailed information on rhizocephalan life history, see Haeg, 1992). As in free-living barnacles, a cyprid larva is the settling stage, and in thoracicans a juvenile barnacle is formed underneath the carapace of the cyprid larva. However, the rhizocephalans develop a so-called kentrogon, which accomplishes the injection of the primordial parasite (Glenner & Høeg, 1995). The degree of specialization towards a specific host means that the cypris larvae of rhizocephalans are extremely selective in their choice of substrata. They will not settle unless a specific host or part of a host, e.g. the gills, is offered. For this reason, the study of settlement and metamorphosis of these species has met with great difficulties.
The ethology of Crenilabrus melanocercus, with Notes on cleaning symbiosis
Authors: Potts Geoffrey W. 
Published: May 2009

Off the coasts of the Eastern Aegean Island of Chios underwater observations were made on the labrid Crenilabrus (= Symphodus) ntelanocercus (Risso).It was found that undisturbed observation could be made from 4 to 5 m away from the fish's territory, but if closer, then diver-orientated behaviour occurred. The fish might inspect the diver, or if alarmed, show fright reactions of different intensities. Conflict situations for the fish sometimes resulted in displacement chaffing. Pursuit caused the fish to show a series of escape reactions depending upon the intensity and persistence of the pursuit. Initially the fish showed avoidance reactions by fleeing or following set ‘escape routes’; further pursuit caused it to hide among the eel-grass, Posidonia; and finally aggregation and flight were resorted to.
An Investigation of Detritus in Southampton Water
Authors: Trevallion Ann 
Published: May 2009

An apparatus is described which has been used at three sites in Southampton Water for the continuous collection of sedimenting detritus. The collected detritus was removed at monthly intervals for measurement, and for analysis of the organic carbon and nitrogen content.The total quantities of dry detritus varied from 4 mg/cm2/month to 980 mg/cm2/month, and because of the variable collection of resuspended bottom material show no clear seasonal variation. The carbon content was 0.1–7.3% of the total and nitrogen varied from 0.02 to 0.62%. The organic content did show some seasonal variation which tended to follow changes in the abundance of phytoplankton.The amounts of total detritus collected and the organic content are high compared with some other areas and this is thought to be due partly to the high primary productivity of the area and partly to the complex water movements in the estuary.IntroductionThe importance of detritus in suspension in the sea and as a superficial layer on the sediment is well recognized. The quantity of detritus in sea water has been measured (Armstrong & Atkins, 1950; Fox, Isaacs & Corcoran, 1952; Krey, 1950, 1961a, b, 1964; Krey, Banse & Hagmeier, 1957; Hagmeier, 1962) and usually exceeds the amount of living material in suspension by at least a factor of ten. Study of deposited detritus has mainly involved measurement of the amount of organic matter in bottom sediments (Waksman, 1933; Anderson, 1939; Southward, 1952; Morgans, 1956; Sanders, 1960).In studies of marine productivity it is important to know not only the amount of detritus present in the water column, but also its composition and rate of sedimentation.
The diet of the two-spot goby, Gobiusculus flavescens (Pisces)
Authors: Potts Geoffrey W. , Edwards Joan , Costello Mark J. 
Published: May 2009

Juvenile and adult two-spot gobies, Gobiusculus flavescens (Fabricius), were collected at three sites in the Plymouth area: the Plymouth Breakwater, Fort Bovisand, and the Yealm estuary. Fish were sampled by a diver-held grab-net, boat-towed zooplankton net, and beam-trawl, from early June until the end of September 1987.Percentage abundance and percentage occurrence dietary data are presented by a graphical technique, such that prey importance (rare or dominant) and fish feeding strategy (specialist or generalist), is visually apparent. It is applied to the different size groups of fish from each site.
Some observations on the behaviour of adult squids,Loligo forbesi, in captivity
Authors: Porteiro Filipe M. , Martins Helen R. , Hanlon Roger T. 
Published: May 2009

Thirty-four adult individuals ofLoligo forbesi(males and females with dorsal mantle lengths from 27–77 cm) were observed in captivity in a 3 m diameter closed sea-water system on Faial Island, Azores. Squids were caught by jigging and were fed with horse mackerel (Trachurus picturatus) and chub mackerel (Scomber japonicus), either alive or dead. The maximum survival was 73 days. Feeding behaviour was dependent upon both the size of prey and its state of preservation;e.g.the squid would eat the head of small fish (< about 15 cm), reject the head of medium-sized fish (about 15–35 cm) and would eat only the dorsal part of a big fish (> about 35 cm) or a fish poorly preserved.Seventeen chromatic, 9 postural and 6 movement components of body patterns were observed and described. Conspecific interactions considered to be aggression and dominance were observed among males; no such interactions occurred when one male and two females were kept together. Body patterns in relation to relaxation, stress, shock, feeding, locomotion and aggression are also described.
The relation between the dimensions of the cirral net, the beat frequency and the size and age of the animal in Balanus balanoides and Elminius modestus
Authors: Crisp D.J. , Maclean F.J. 
Published: May 2009

The expected allometry between the linear cirral length and animal volume or weight for isometry should be 0·33; similarly the rate of beating, db/dt, might also be expected to increase as −0·33 with volume. The average allometry index of cirral length is less in both Balanus balanoides (0·22–0·23) and in Elminius modestus (0·27–0·32). The segment numbers also rise less than expected.The rate of beat in Balanus balanoides correlates well with size (-0·28) and with temperature with a correlation coefficient of 0·898, significant for both variables. For a group of 11 species the relation between maximum rate of beating and size over 5 decades gives an approximate allometry of −0·24 which is also less than the expected −0·33 for an isometric linear appendage moving at constant velocity. It is suggested that the approximately reciprocal allometry index between cirral beating rate (−0·28) and cirral length (+0·22) may be mutually compensating, resulting in the cirri moving through the water at a constant rate during the growth of the animal. This rate may maximise the chance of prey being captured.
Beak Length Analysis of Moroteuthis Ingens (Cephalopoda: Onychoteuthidae) from the Falkland Islands Region of the Patagonian Shelf
Authors: Jackson George D. , Buxton Nicole G. , George Magnus J.A. 
Published: May 2009

A detailed analysis of beak length to body length and weight measurements was carried out for the onychoteuthid squid Moroteuthis ingens, in the Falkland Islands region of the South Atlantic. Lower and upper rostral lengths were both good predictors of mantle length and body weight. In addition, the relationships of freshly dissected beaks to mantle length and body weight were significantly different to those of beaks dried before measuring, with dried beaks being better predictors of both variables.A considerable amount of information on Southern Ocean squid biology has been obtained from analysis of beaks in the stomach contents of predators (Clarke, 1980,1983). Beak analysis can be particularly useful as it provides information on the species preyed upon as well as estimates of squid size and biomass ingested (Clarke, 1983, 1986).
A ‘Hyaline’ Layer in the Skin of Squids
Authors: Madan J.J. , Wells M.J. 
Published: May 2009

The skin ofLoligo vulgarisandIllex illecebrosuscontains a thick layer of amorphous material. InLoligoit lies above and inIllexbelow the chromatophore layer. We can find no mention of this layer in the considerable literature on squid skins despite its potential importance as a protection to underlying tissues and as a possible barrier to cutaneous oxygen uptake.Cephalopods have soft complicated skins. Embedded in the skin, most species have chromatophores, small bags of pigment that can be expanded by muscles that are under direct nervous control from the brain. There is an extensive literature on the physiology of chromatophores (Packard, 1988) and on their function in the behaviour of the animals (Hanlon & Messenger, 1996; Packard & Hochberg, 1977). Further cutaneous structures concerned in the determination of the colour of living cephalopods, the reflecting iridophores and leucophores (Cloney & Brocco, 1983), and the light generating photophores (Herring, 1988), have been the subject of a number of reports but other skin features such as the distribution of blood vessels have attracted little attention.
Alectona Species From North-Western Pacific (Demospongiae: Clionidae)
Authors: Bavestrello Giorgio , Calcinai Barbara , Cerrano Carlo , Sarà Michele 
Published: May 2009

Alectona species which bore into the scleraxis of several colonies of Corallium elatius and the stem of a stylasterid coral, Distichopora sp. have been studied. The genus Alectona consists of rarely collected species. Five species, of the eight known for the genus, are here recorded. Two new species of Alectona sorrentini and A. microspiculata and one uncertain species are described.In recent reefs Cliona species are the predominant boring sponges while Alectona and Thoosa were common in the Eocene/Miocene coral reefs. The deep precious red coral communities of the western Pacific may be interpreted as refuge habitats of these ancient boring sponges.
On the feeding habits of Aphrodita aculeata and commensal polynoids
Authors: Mettam C. 
Published: May 2009

A recent review of polychaete diets (Fauchald & Jumars, 1979) considered aphroditids to be slow-moving carnivores, taking microscopic prey if nothing else is available but specializing in slow-moving or sessile prey. This opinion was based on remarks by Day (1967) and on two documented gut analyses of Aphrodita aculeata (Blegvad, 1914; Hunt, 1925). Other reports in the literature were either derived from these few original statements or else gave unsubstantiated accounts of the type of food taken.In 1964 the late Gunnar Thorson told me that he had seen a specimen of A. aculeata swallowing a large Nereis virens and likened it to a hedgehog eating a snake. This vivid analogy puts Aphrodita in a rather different light, as an active predator capable of dealing with relatively large, powerful prey. In fact Hunt (1925) had recorded remains of ‘Pectinaria, Lumbriconereis, Polynoidae and Nereidae’ in 24 out of 26 specimens containing food. Very young crabs and hermit crabs were recorded in five guts and a nemertean in one. Blegvad (1914) recorded the chief food to be other worms, especially sabellids and terebellids, besides nemerteans, from examination of 50 specimens, 35 of which were empty.I have kept A. aculeata, obtained from Millport and from Plymouth, in bowls containing several centimetres depth of beach sand in a closed-circuit sea-water system. Worms without sand took no interest in items offered as food, neither did worms which had emerged from the sand and were wandering over the surface, but buried worms fed readily. A variety of living animals was given as potential food including Macoma balthica, Corophium volutator, Nephtys hombergi and Nereis diversicolor.
The vertical distribution and diurnal migrations of calanoid copepods collected on the Sond cruise, 1965 IV. Systematic account of families Lucicutiidae to Candaciidae. the relative abundance of the numerically most important genera
Authors: Roe H. S. J. 
Published: May 2009

The vertical distributions and diurnal migrations are analysed for nineteen species of calanoid copepods in the families Lucicutiidae up to and including the Candaciidae. The relative abundance, both vertical and horizontal, is given for each species.With few exceptions most of these species show little or no vertical migration. There is some suggestion of a reversed (downward) migration for Paracandacia bispinosa andP. simplex but since there are difficulties in analysing the surface samples the evidence is inconclusive. The species which are abundant in the family Heterorhabdidae all have little or no vertical migration and are at least partially vertically segregated by both day and night. Phyllopus impar and P. helgae are clearly vertically segregated and Haloptilus acutifrons and, to a lesser extent, H. ornatus each have two vertically separated populations by both day and night. Two size groups are present in each sex of Lucicutia flavicornis.The vertical distributions and numbers throughout the water column are analysed for 203 and 176 species in the day and night series respectively; it is concluded that while many species are relatively abundant at one or more particular depth most of them are numerically relatively insignificant in the water column as a whole. Only two species (day) and four species (night) formed more than 5 % of the total numbers caught in their respective series.The relative abundance, both vertical and horizontal, of the commonest genera are analysed. In the whole water column the relative abundance of most of the genera is constant by both day and night, and, as with the individual species, most of them are relatively scarce.
On the nutrition and metabolism of zooplankton XIII. Further studies of steroids inCalanus
Authors: O'Hara S. C. M. , Gaskellf S. J. , Corner E. D. S. 
Published: May 2009

The presence inCalanus finmarchicusof the sex hormone oestradiol-17β has been confirmed by gas chromatography-mass spectrometry (GC-MS) using the trimethylsilyl and heptafluorobutyrate derivatives.Levels of the sex hormone testosterone have been measured by radioimmunoassay inCalanus helgolandicuscollected from Plymouth Sound, and inC. finmarchicuscaptured off the Norwegian coast. Concentrations inC. helgolandicusvaried during the year from 150 to 626 fg/animal, accounting for 2.3 to 437 x 10-7% of the lipid content and 10.8 to 64.8 x 10-6%percnt; of the total sterol fraction. The mean level in Stage V C.finmarchicus,captured during spring, was 196 fg/animal.Testosterone was identified in C.finmarchicusby GC-MS of thetert-butyldimethylsilyl derivative.
Fish otoliths from the stomach of a thresher shark, Alopias vulpinus
Authors: Pascoe P. L. 
Published: May 2009

INTRODUCTIONOn the 16 June 1982 a thresher shark, Alopias vulpinus (Bonnaterre, 1788), became entangled in a gill net at Bigbury Bay, S. Devon. The stomach contents were found to consist solely of teleost otoliths. The soft tissues of prey taken by large marine predators are often macerated and digested very rapidly or, as in this case, regurgitated during capture or stranding. Identification of the prey is therefore only possible from the hard parts which often remain, e.g. teleost otoliths, bones and scales, and cephalopod beaks, statoliths and gladiuses. The regular seasonal occurrences in the waters off south-west England and south-west Ireland make the thresher the most common of the large sharks in this area. Their accidental capture or collisions with nets are not rare and they have been taken by rod and line on several occasions.
Occurrence, composition and function of intracellular calcium phosphate granules in the musculature of nephtyid polychaetes (Annelida)
Authors: Bryan G. W. , Gibbs P. E. 
Published: May 2009

INTRODUCTIONIntracellular calcium granules rich in phosphorus are found throughout the animal kingdom and occur in a wide range of different tissues (Simkiss, 1976; Mason & Nott, 1981). However, few examples of the natural occurrence of such granules in muscle cells have been recorded and thus the discovery of abundant granules composed of calcium phosphate within the muscle fibres of the polychaeteNephtys, described by Gibbs & Bryan (1984), is of considerable interest, particularly regarding the formation and function of these unusual sarcoplasmic inclusions.
Modalities of brooding and morphogenesis of larvae in Ostrea puelchana (D'Orbigny) under experimental rearing
Authors: Castro Nora Fernandez , Pennec Marcel Le 
Published: May 2009

Ostrea puelchana is a larviparous oyster from the S.W. Atlantic coasts. This species is not being commercially exploited at present. Because of its high food qualities, however, it may constitute a resource of economic interest in the future.Until now larval development and characteristics of the incubation period have been poorly known. This study describes the characteristics of the mode of brooding under laboratory rearing conditions and, using scanning electron microscopy, the morphogenesis of the hinge until larval release from the parents.The larva develops two anterior and two posterior denticles during brooding. A comparison with larvae of other species of the genus Ostrea reveals that the main differences among them do not lie so much in the pattern of hinge dentition as in the rate of evolution of the hinge components, which is faster in Ostrea puelchana. This species has fully developed denticles at the time of release, which places the larva of this oyster as particularly evolved within the genus Ostrea.
Disappearance of the warm-water hermit crab Clibanarius erythropus from south-west Britain
Authors: Southward A. J. , Southward Eve C. 
Published: May 2009

The hermit crab Clibanarius erythropus first reported from Britain in 1961 is no longer present. There appears to have been no further recruitment since the late 1950s when there was a favourable combination of climate and hydrographical factors that led to successful invasion of Devon and Cornwall.The population appears to have succumbed to the combined effect of age and declining temperatures. Additional contributory factors in the decline could be the mortalities resulting from the ‘Torrey Canyon’ disaster; the reduction in numbers of the dog-whelk (whose empty shells are the favoured home of the crab in Britain) as a result of organotin antifouling paints; and increased public pressure on the habitat.
A New Method for Growing Hydroids in Small Aquaria by means of a Continuous Current Tube
Authors: Browne Edward T. 
Published: May 2009

The simple piece of apparatus, to which I give the name “Currenttube” was made last year in the Marine Laboratory at Plymouth. I designed it especially for growing Hydroids, and for them it has proved to be a success; but it should also be useful for other fixed organisms, such as sponges, polyzoa, and ascidians.The previous methods which I had used for growing Hydroids in bell-jars or small aquaria never gave complete satisfaction. Occasionally a success was recorded, but there were too many failures, which frequently involved a great waste of labour.
On Phellia murocincta (Gosse)
Authors: Walton Chas. L. 
Published: May 2009

P. H. Gosse described this beautiful little species in his British Sea Anemones and Corals, in 1860, from two specimens obtained from a pool at Petit Tor, near Torquay.I recently collected two specimens at Zennor, some five miles along the coast south of St. Ives, Cornwall.An examination of these proved that Gosse's examples were young and immature, as shown by the difference of size and number of tentacles.
Morphological Variability in Illex Coindetii (Cephalopoda: Ommastrephidae) Along the North-West Coast of Africa
Authors: Hernández-García V. , Castro J.J. 
Published: May 2009

This paper gives morphometric variations and dorsal mantle length–total weight (DML-TW) relationships for Illex coindetii in the eastern Central Atlantic area. Positive allometry was observed in males and negative in females of the species. The most variable body measurements between males and females were width and perimeter of the head. In the study area, divergence of morphometric measurement starts at 95 mm. The point of divergence, however, varies with latitude; fluctuating from 104 mm in the north (Morocco and Sahara) to 76 mm in the central area (Mauritania and north of Senegal) and 73 mm in the south (Gulf of Guinea).The relationships between DML and TW showed that sexual dimorphism due to differential growth between males and females starts to occur at 56 mm ML. The starting point of sexual dimorphism (56 mm) varies according to the zone; the higher the latitude, the later it occurs. Thus, sexual dimorphism occurs at 49 mm in the south (Gulf of Guinea), at 54 mm in the central area (Mauritania and north of Senegal) and at 74 mm in the north (Morocco and Sahara). Females grow larger than males, but males were heavier at any given length. As latitude decreased, a slow down in the increase in weight-at-length was observed in both sexes.