Barnacle Research Articles

Influence of the heavy metals copper and cadmium on the behaviour of Semibalanus balanoides and Balanus crenatus

The effect of the heavy metals copper and cadmium on the behaviour of the sessile barnacles Semibalanus balanoides and Balanus crenatus over periods of 24 hours to 15 days has been studied using a photoelectric system to monitor cirral activity. In unstressed barnacles the amount of cirral movement remained fairly constant for several days although there was a marked decrease in the level of activity in animals kept in the laboratory for extended periods of time. In contrast to the response exhibited by bivalve molluscs, exposure to copper or cadmium did not elicit a rapid closure response in the barnacle. However, sublethal (80 ppb Cu, 100 ppb Cd) as well as lethal (500 ppb Cu, 500 and 1000 ppb Cd) levels resulted in a significant (P<0.05) overall reduction (averaging 30%) in the amount of cirral movement although at lethal levels there was often a period of increased activity prior to the onset of morbidity. Cirral beat frequency and duration were not often affected by exposure to 80 ppb of copper or 10...

Potential fishery for the gooseneck barnacle Pollicipes polymerus (Sowerby, 1833) in British Columbia

The gooseneck barnacle, Pollicipes polymerus, is an abundant organism on exposed foreshores of British Columbia and may support a modest fishery. Sexual maturity is attained in 1 year, harvest size in 5 years. Harvesting is limited by the tidal cycle and exposure to wave surges. Potential harvest rates are expected to be ∼70 kg per tide per person, about half the animals are of a suitable size for the European market. To provide live products to this market, the animals should be kept at temperatures of between 6 and 9°C, but even then will generally not survive for longer than 8 days without appreciable loss. A limiting factor to the long-term exploitation of P. polymerus is that resettlement may det taken place in harvested areas during the 7 years of this study. It appears that resettlement may depend on an initial settlement of the small sessile barnacle Semibalanus glandula and may thus be a slow process of ecological succession.

MARINE VEGETATION OF THE MUSERI AND ENTEDEBIR ISLANDS (DAHLAK ARCHIPELAGO, RED SEA)

The intertidal and shallow subtidal marine vegetation of two uninhabited islands in the Dahlak Archipelago, southern Red Sea, is described. The vegetation of these habitats is representative of the entire Archipelago, except for its seaward periphery. Under the highly sheltered conditions prevailing in most of this area, life in the intertidal and in the shallows is rather depauperated, the upper intertidal levels being mostly affected. On the rocky shores, the rarity of periwinkles is the most striking feature at these levels; a little lower down, barnacle belts are completely absent. Species diversity is rather low in the algal communities of the lower intertidal and the upper subtidal. Sciaphilic habitats at these levels harbor a more diverse vegetation, in which a number of species not previously reported from the Red Sea have been encountered. Mangal stands occur in the more sheltered sites. Avicennia marina belts are present in all mangal stands, Rhizophora mucronata belts occur in the highly sheltered sites on the leeward side of the Museri Island, while a single small stand of Ceriops tagal has been observed in a protected depression on the adjacent Desta Island. Bostrychietum, considered for a long time to be nonexistent in the Red Sea, has been found on A. marina aerial roots from an extremely sheltered location in the Melita Bay, Gulf of Zula, on the Ethiopian mainland coast. Caulerpetum serrulatae covers clayey bottoms in ca. 100 m deep troughs between the islands. It is exclusively composed of the low-light ecophene of Caulerpa serrulata , which differs from the normal, high-light form in bearing flat, ribbon-shaped assimilators.

Complemental Male in the Primitive Balanomorph Barnacle, Chionelasmus Darwini

A complemental male was found on a solitary specimen of the primitive sessile barnacle Chionelasmus darwini. It was located on the scutal apex of the hermaphrodite and accommodated by a notch in the tergum. Its resemblance to complemental males of Bathylasma adds weight to the classification of the genus in the family Pachylasmidae rather than the Catophragmidae. Phylogenetic implications are discussed.

Extending Darwin's investigations on the barnacle life-history

Darwin's magnificent study of the stalked, sessile and fossil barnacles, perhaps his greatest work, was started not many years after the systematic position of cirripedes within the class Crustacea had been accepted. It was completed at a time when histology and microtomy were not developed and when living specimens could only be seen on occasional visits to the seaside. Yet 130 years later it remains the standard text. It was on a visit to Tenby that he observed that barnacles were sensitive to vibration and, in seeking an acoustic organ, he mistakenly seized upon the oviducal gland. This led to an ever increasing series of misinterpretations of the female generative mechanism. Associated with this error was the belief that the ovary and cement glands were homologous in both cyprid and adult. He later confessed to “having blundered terribly over the cement glands”, but it was probably his search for examples of organs changing their function during evolution that led to this blunder. Similarly, he convinced himself mistakenly that the ovigerous fræna, which hold fast the egg masses to the mantle lining in stalked barnacles, became modified to gills in sessile barnacles. Darwin's interest in barnacle reproduction led to his discovery of complemental males attached to hermaphrodite individuals. He proved that they were dwarf cirripedes and not parasites. His knowledge that male and hermaphrodite flowers could co-exist helped him to accept that these apparently unnecessary beings could be present also in barnacles. We now know that complemental males are not confined to stalked barnacles but are also present in certain balanids. Though Darwin did not include the dioecious parasitic group, the Rhizocephala, in his studies, he recognized the wide repertoire of sexual arrangements from hermaphroditism to dioecy which now provides challenging material to our further understanding of sex allocation, control and evolution. Since Darwin dealt mainly with dried or preserved specimens he did not describe any of the details of the liberation of nauplii or the searching behaviour of the cyprid. Current investigators have shown that the former involves a prostaglandin which activates the embryos. Searching cyprids have been shown to be able to recognize their own and other species. Charles would have seen in this phenomenon a relevance both to survival and to the evolution of epizoic barnacles. Despite Charles' belief that his barnacle work would be “for ever unapplied” it has in fact been the foundation on which all studies of commercially important barnacle fouling have been based.

THE LARVAL COMPOUND EYE OF BARNACLES

The compound eye of the cypris larva of Balanus crenatus comprises about 10 ommatidia. The ommatidia possess a crystalline cone formed by three cone cells, two distal pigment cells, and six retinular cells that together form the rhabdom. The compound eye of the cypris larva of Balanus exhibits similarities to that of branchiurans and ostracodes, but the latter two groups share more common characteristics. Adult barnacles have reduced nauplius eyes (Fahrenbach, 1965; Krebs and Schaten, 1976). Their sessile life requires little visually stimulated behaviour, the shadow reflex being the best known (Gwilliam, 1963). The planktonic larval forms, known as nauplii, have well-developed nauplius eyes (Kauri, 1962) capable of serving in light/dark perception. Between the planktonic nauplii and adult sessile forms, a short-lived cypris appears (Bookhout and Costlow, 1959), adapted for settlement. In contrast to all other stages, the cypris larva has a pair of small but morphologically well-differentiated compound eyes (Fales, 1928; Walley, 1969). The settlement behaviour has been analysed and the role of light guidance has been established (Barnes et al., 1951). Nothing is, however, known about the fine structure of the eyes of the cypris larva. Further, the kinship of the barnacles (Cirripedia) with related groups is poorly known as regards eye structure. The structure of the nauplius eye places the barnacles in the maxillopod-ostracode group (Elofsson, 1966). The present study was undertaken to elucidate the above problems.

Intrapopulation Variation in Growth of Sessile Organisms: Natural Populations of the Intertidal Barnacle Balanus balanoides

A dominance-suppression hierarchy has been invoked to explain changes in the size-frequency distribution of plants undergoing self-thinning in monospecific stands. Dominant individuals supposedly grow at the expense of suppressed individuals, causing a shift from a normal distribution of sizes to a log-normal distribution during the growth season. I examine the predictions of this model for natural populations of sessile barnacles growing under space competition. The general pattern of growth is consistent with self-thinning; individuals growing at high population density are smaller than those growing at low population density. The pattern of mortality is consistent with the development of a dominance-suppression hierarchy under conditions of crowding; small individuals die at higher rates than larger individuals. The pattern of individual variation in growth is however inconsistent with dominance and suppression; there are reversals in the rank order of sizes during the growth season, and the skewing of the size distributions does not increase over the growth period. The lack of a dominance-suppression hierarchy in relation to growth may be the result of random variation in capture of large food items; individuals which happen to ingest large food particles may grow rapidly while their neighbours do not.

Seasonal and short-term variations in abundance of barnacle larvae near the South-West of the Isle of Man

Larvae of five species of sessile barnacles were found to be common within 4 miles of Port Erin, Isle of Man. These are Balanus balanoides, B. crenatus, B. balanus, B. hameri and Verucca stroemia. Larvae of other recorded species were very rare or absent. The major larval release of all the common species occurred in late winter and spring, but V. stroemia continued to breed throughout most of the year, and there was some evidence of autumn breeding of B. crenatus on a very small scale. The major release of nauplii by most of these species occurred at the time of the spring diatom outburst. The larval life of each of the four species of Balanus is estimated to last 3–5 weeks, that of V. stroemia 7–8 weeks. Some observations suggested that the larval release of B. balanoides may be stimulated by spring tides, but other observations seemed to contradict this. Larval release may be inhibited by turbulence.

NOTES ON THE DISTRIBUTION AND BIOLOGY OF GALATHEIDAE AND CHIROSTYLIDAE (DECAPODA: ANOMURA) FROM THE MIDDLE ATLANTIC BIGHT

ABSTRACT Twelve species of Galatheidae and one species of Chirostylidae numbering 6,928 individuals were retrieved from trawl collections made on the continental shelf, slope, and rise in the Middle Atlantic Bight. The most abundant species collected was Munida iris iris which constituted >90% of the total catch of galatheoidean anomurans. Three other species (Munidopsis rostrata, Munida valida, and Munida longipes) comprised > 1% of the total number of Galatheoidea. The bathymetric distribution of Munidopsis spp. was confined to depths >500 m, whereas all except two Munida spp. were collected from the continental shelf and upper slope. Munida spp. and Eumunida picta produced large numbers of small eggs, whereas eggs from Munidopsis spp. were large and few in number. Ovigerous females of all species examined, except Munida microphthalma and Eumunida picta, had larger carapace lengths than males and other females. For most species, there was little evidence of reproductive seasonality since ovigerous females were collected throughout the year; however, ovigerous females of Munida longipes, Munidopsis bairdii, and Eumunida picta were collected only in fall or winter. Parasites of Galatheoidea were mainly bopyrid isopods and rhizocephalan barnacles. The incidence of parasitism was low for all species examined.

A study of the oviducal glands and ovisacs of Balanus balanoides (L.) together with comparative observations on the ovisacs of Balanus hameri (Ascanius) and the reproductive biology of the two species

A mainly microscopical study has been carried out on the oviducal glands and ovisacs of two hermaphroditic sessile barnacles, Balanus balanoides and Balanus hameri . In both species each gland secretes an ovisac, once a year, for a very restricted period before copulation. The morphology of the glands of B. balanoides has been worked out from serial sections and a Plasticine model. Three regions have been established within the glands; two are ectodermal in origin, namely the main chamber and exit canal, while the third, the proximal chamber, is mesodermal. The exit canal is always lined with cuticle, but the main chamber for most of the year is not. However, in both species main chamber cells begin to secrete the ovisacs several weeks before copulation. Ovisacs are undoubtedly cuticular structures. The cytology of B. balanoides main chamber cells during the sequence of events leading to the formation of ovisacs has been followed by means of transmission electron microscopy. The cells each develop a long apical cytoplasmic extension; from these extensions and the apical cell surfaces secretions pass out to form the ovisac wall. This wall has two zones, an outer electron-dense zone 14 pm thick and an inner flocculent zone 6 pm thick. When fully formed the ovisac is released from the main chamber cells to lie in the oviducal gland lumen, although the neck of the ovisac continues to be firmly attached to specialized anchor cells. The cytoplasmic extensions of the main chamber cells break away with the ovisac as it is released and eventually form the pores in the ovisac wall. Scanning electron microscopy was used to examine such unstretched sacs. In B. balanoides the main chamber cells then partially retrogress, shedding secretions and portions of cytoplasm into the gland lumen. It is proposed that these ‘formed bodies’, by their osmotic activity, draw water and low molecular mass solutes into the gland lumen from the haemolymph. The ‘formed bodies ’ swell and burst, thereby accumulating fluid in the lumen of the gland, which becomes highly swollen. It is this fluid that has the activating factor(s), thought to be the ammonium ion, needed to activate inseminated sperm. In this condition B.balanoides becomes a receptive female. In B. hameri , although there is some retrogression of the main chamber cells with secretion of ‘formed bodies’, there is much less accumulation of fluid and so the oviducal glands do not become so highly swollen. The copulatory act of B. hameri was observed closely and comparison was made with that of B. balanoides . In B. hameri a single male is involved and a single insemination is sufficient for egg laying to commence, while in B. balanoides more than one male may be involved and multiple inseminations are needed before egg laying begins. Oocytes (eggs) pass from the ovaries down the oviducts and into the elastic ovisacs lying in the oviducal glands. As the ovisacs distend with eggs they first expel the oviducal gland fluid into the mantle cavity and then they themselves are forced out into the mantle cavity. As the stretching continues the ovisac wall becomes very thin and the pores enlarge. Although B. balanoides sperm, which are 0.5 pm in diameter, can easily pass into the 0.7 to 1.6 pm diameter pores of an unstretched ovisac, those of B. hameri , which are also 0.5 pm in diameter, need the ovisac to stretch and the pores to enlarge from their original diameter of 0.2 pm before sperm can pass through and fertilize the eggs. Inseminated sperm, in both species, are deposited as gelled masses. In B. balanoides the expelled oviducal gland fluid activates such sperm, but inseminated sperm of B. hameri become active in seawater. At any one time, only those sperm on the outer surface of the masses are active, and so a staggered release takes place. This is essential when egg laying takes more than 30 min and the sperm of B. balanoides and B. hameri are active for only 5-6 min and 12-13 min respectively. The fully formed egg masses are finally freed from the anchor cells within the glands and moved to the bottom of the mantle cavity, where egg development takes place.

Absence of gregarious settling Behaviour by female cypris larvae of British parasitic rhizocephalan barnacles

Barnacle cypris larvae, the specialized settlement stage of the life-cycle, are classical examples of larvae showing gregarious settlement. Gregarious settlement is shown when the larva is induced to settle by established individuals of its own or of a closely related species, reflecting the ability of the larva to recognize its own type, usually by chemo-tactile detection of a particular settlement inducing factor (see Crisp (1974) for review). Sessile barnacles such as species of Balanus or Chthamalus are typically hermaphrodite and gregarious settlement is of selective advantage in promoting the possibility of cross-fertilization, in addition to allowing a settling larva to identify a habitat providing all the necessary conditions for barnacle growth and development.

The morphology of the central nervous system of the barnacle, Semibalanus cariosus (Pallas).

The central nervous system of the sessile barnacle, Semibalanus cariosus (Pallas), has been studied with the particular aim of determining the locations of neuron somata in relation to peripheral nerves. This was accomplished by tracing peripheral nerves using dissection and methylene blue staining techniques, histological methods, and by permitting cobaltous chloride to diffuse via axons into ganglia ("backfilling"). The neuron maps resulting from the study reveal some well-defined sub-systems, a considerable degree of functional clumping of neuron somata, and some unexpected projections of neurons in the CNS. Neurophysiological studies based on these findings are in progress.

The biochemical composition ofLepas anatifera(L.) cement (Crustacea: Cirripedia)

In an earlier study of the biochemical composition of barnacle cement, Walker (1972) found that the cements of two sessile barnacles,Balanus hameriandB. crenatuscontained small amounts of lipid (&lt; 1% of total dry wt.) and carbohydrate (♎ 2% of total dry wt.) but were mainly composed of protein ( &gt; 85 % ° of total dry wt.). Lindner &amp; Dooley (1973) similarly found that a large proportion ofB. crenatuscement was protein (80%), but Cook (1970) found only 70% protein, lipid (27.4%) being the other major constituent. There is therefore general agreement that barnacle cement is mainly a proteinaceous secretion, but controversy still exists over the amount of lipid present.

Stimulation by aldosterone of the sodium efflux in barnacle muscle fibres

Es wurde gezeigt, dass die Natrium-Ausscheidung in der Muskelfaser von Entenmuskeln auf aldosteron reagiert.

Sensitivity of the Na efflux in barnacle muscle fibres to the microinjection of troponin-C.

Nachweis, dass eine Microinjektion von Troponin-C den Na-Ionen-Ausfluss aus Einzelfasern des Entenmuschel-Muskels steigert.

The influence of thymol on the sodium efflux in barnacle muscle fibres.

Nachweis, dass Thymol sowie Coffein in der Barnakel-Muskelfaser eine primare Hemmung mit nachfolgender Stimulierung des Natrium-Auswartsstromes hervorruft.

A Study of the Effects of the San Francisco Oil Spill on Marine Organisms

ABSTRACT The San Francisco oil spill occurred on January 18, 1971, during the early morning hours when two Standard Oil vessels collided almost directly under the Golden Gate Bridge, releasing 840,000 gallons of Bunker C fuel. This asphalt-like oil was washed up on intertidal shores of the area. Duxbury Reef, northwest of the Golden Gate Bridge, is literally the “backyard” of the author and the College of Marin's Bolinas Marine Station staff. Baseline transects have been established on this reef since 1958. The oil was heavily deposited on the reef's mussel beds and high tidal berm rocks. From comparative transect and laboratory observations, it was determined that marine organisms died from being smothered by the oil, with certain species, such as acorn barnacles and limpets, suffering the highest mortality at Sausalito and on Duxbury Reef. Comparison of pre-oil and post-oil transect counts showed there was a significant decrease in marine life after the oil spill on the reef Marine snails suffered less mortality than the sessile barnacles and other sedentary animals. The normally large population of striped shore crabs is missing from the rocky crevices. Finally, marine algal blooms were also observed in certain reef localities. The present condition of Duxbury Reef (December, 1971) is one of apparent good health; the recruitment of some marine animals appear to be approaching normal levels. The oil has disappeared from much of the reef surfaces and is barely discernible in the most heavily deluged areas. Continued studies will be aimed at watching the effects of oil on the recruitment of marine life throughout the afflicted areas of the Marin County coastline.

Inhibition of the CO2-sensitive Na efflux in barnacle muscle fibers by micro-injection of ethacrynic acid

Es wird gezeigt, dass die Mikroinjektion von Athacrynsaure [2,3-Dichloro-4(2-methylenbatyryl)-phenoxyacetsaure] in die isolierte Muskelfaser der Entenmuschel nur dann den Natriumausstrom herabsetzt, wenn die Badelosung vorher angesauert wird.

THE HEBREW UNIVERSITY—SMITHSONIAN INSTITUTION COLLECTIONS FROM THE SUEZ CANAL (1967–1972)

ABSTRACT Results of a recent collection of marine fauna and flora from the Suez Canal are reported. The data on the samples and the taxa sorted from them are summarized in table form, for basic reference. Identification lists for several taxa are included: Hydrozoa, Cirripedia, Mysidacea, Cumacea, Amphipoda-Caprellida, Decapoda, Echinodermata—Echinoidea, Asteroidea, Ophiuroidea, Holothuroidea; Tunicata—Ascidiacea. Comparison is made with the 1924 Cambridge Expedition to the SuezCanal. Zoogeographic conclusions are presented, indicating the relative stability of the Suez Canal biota in the past 50 years, the predominance of Red Sea species over Mediterranean ones and the presence of an estuarine element.

Sensitivity of sodium efflux in barnacle muscle fibers to the microinjection of calcium chloride.

Nachweis, dass der Auswartsstrom von Natrium aus Muskelfasern der ArthropodenBalanus nubilus undBalanus aquila in kunstlichem, kaliumfreiem Meerwasser durch Mikroinjektion von Kalziumchlorid aktiviert wird.