H. Barnes

Oceanography and marine biology : an annual review

Confusion Reigns? A Review of Marine Megafauna Interactions with Tidal-Stream Environments Steven Benjamins, Andrew C. Dale, Gordon Hastie, James J. Waggitt, Mary-Anne Lea, Beth Scott & Ben Wilson Climate-Driven Trophic Cascades Affecting Seabirds around the British Isles Alan MacDonald, Michael R. Heath, Martin Edwards, Robert W. Furness, John K. Pinnegar, Sarah Wanless, Douglas C. Speirs & Simon P.R. Greenstreet Circumglobal Invasion by the Brown Seaweed Sargassum muticum Aschwin H. Engelen, Alexandra Serebryakova, Put Ang, Kevin Britton-Simmons, Frederic Mineur, Morten F. Pedersen, Francisco Arenas, Consolacion Fernandez, Henning Steen, Robin Svenson, Henrik Pavia, Gunilla Toth, Frederique Viard & Rui Santos Simple, Scale-Dependent Patterns Emerge from Very Complex Effects-An Example from the Intertidal Mussels Mytilus galloprovincialis and Perna perna Christopher D. McQuaid, Francesca Porri, Katy R. Nicastro & Gerardo I. Zardi The Contribution of the Genus Littorina to the Field of Evolutionary Ecology Emilio Rolan-Alvarez, Christopher J. Austin & Elizabeth G. Boulding Spatial, Temporal and Taxonomic Variation in Coral Growth-Implications for the Structure and Function of Coral Reef Ecosystems Morgan S. Pratchett, Kristen D. Anderson, Mia O. Hoogenboom, Elizabeth Widman, Andrew H. Baird, John M. Pandolfi, Peter J. Edmunds & Janice M. Lough

EGG SIZE, NAUPLIUS SIZE, AND THEIR VARIATION WITH LOCAL, GEOGRAPHICAL, AND SPECIFIC FACTORS IN SOME COMMON CIRRIPEDES

Where possible the eggs, separated from the egg-masses, were measured fresh; when the material had to be preserved Gilsons fluid was used. This helps to break up the egglamellae and, if they are reasonably ripe, eggs are separated on gentle agitation. Ova were shaken out of the ripe ovaries and allowed to round off for 30 min before being measured. Nauplii were measured lying on their dorsal side; for stage I the total length from anterior to posterior and the greatest width of the carapace were measured. The measurements were made under a binocular microscope using a scaled eye-piece which was read to the nearest 0 5 division; the magnification was such that the eggs were about 40 scale divisions, with 1 division -6-0 It. When focusing problems on ellipsoid eggs at higher magnifications are taken into account a moderate magnification of this order seems adequate even though higher magnification may give an appearance of greater accuracy. Where possible at least 200 eggs, obtained by pooling aliquots from a number of individuals, were measured.

Egg numbers, metabolic efficiency of egg production and fecundity; Local and regional variations in a number of common cirripedes

Abstract The various terms which have been used to describe some quantitative parameters of considerable importance in the reproductive cycle of marine invertebrates are discussed; egg number, fecundity and the metabolic efficiency of egg production are defined in a way applicable to animals such as many crustaceans in which the number of eggs produced is a function of adult size. The variation with tidal level and latitude of egg numbers as well as their changes from one season to another are described and discussed for a number of common cirripedes. Local factors may often obscure latitudinal variations. There is no evidence that egg numbers or fecundity are greatest under poor conditions or at the limits of distribution; indeed the reverse seems to be the case. The metabolic efficiency of egg production, namely, the weight of egg tissue produced per unit time per standard increase in body weight is relatively constant for many operculate species even when they are of different adult or different egg size. It follows that fecundity, the number of eggs produced per unit time per standard increase in body size, is largely a function of egg size. The importance of these factors to the ecology of the animals and to their distribution is discussed.

Seasonal changes in the acutely determined oxygen consumption and effect of temperature for three common cirripedes, Balanus balanoides (L.), B. Balanus (L.) and Chthamalus stellatus (Poli)

Abstract The QO2 of three common cirripedes has been measured at four temperatures and on each of four occasions during a year: dissected bodies were used. Statistical analysis indicates that only infrequently is the Q10 weight dependent. Such dependence seems to be related to the nutritional conditions in the environment rather than to the internal state or species habitat. Q10 varies widely even in a given species. In Balanus balanoides there is a marked homeostasis at certain seasons as there is in Chthamalus stellatus at other seasons: Balanus balanus shows somewhat less marked homeostasis. A low Q10 of basal metabolic rate in littoral invertebrates has been observed by others in a variety of animals. The results of some relevant previous work are critically examined and compared with those of the present investigation.

Studies on the reproduction of cirripedes. I. Introduction: Copulation, release of oocytes, and formation of the egg lamellae

Abstract A brief outline is given of the sequence of events leading to the production of egg lamellae in operculate and pedunculate cirripedes. Details are given of the copulatory act as regards random and possibly directed movements of the penis; the question of mutual ‘recognition’ is discussed. The time spent by a spermatozoon in the penis is estimated. The release of ripe oocytes is described and the results of some experiments suggesting the presence of an agent suppressing their release in the earlier stage of maturation are given. It is shown that seminal plasma can induce muscle contractions and the possible significance of this is discussed. The behaviour subsequent to copulation is described. Fully motile spermatozoa are found in the mantle cavity and may be expelled in the mantle cavity current. The bulk of the semen sets to a translucent jelly which is eventually lost from the mantle cavity. The formation of this gel is due to general autolysis. The production, properties, and functions of the egg membranes and the oviducal sac are discussed.

The effect of starvation and feeding on the time of production of egg masses in the boreo-arctic cirripede Balanus balanoides (L.)

Abstract The effect of starvation for various periods and also at various times during the development of the ovaries of Balanus balanoides (L.), followed by feeding, has been investigated. The total feeding time to full maturation shows little variation. The time at which the egg masses are laid down can, however, be to some extent manipulated by controlling the starvation period.

A comparison of the annual growth patterns of Balanus balanoides (L.) with particular reference to the effect of food and temperature.

The annual growth in temperate waters of a number of cirripedes appears to be very similar: during the first year, rapid growth of the young spat follows the spring settlement and is succeeded by more moderate growth rates as the size increases during the summer; subsequently, in the autumn and winter little further growth takes place. This pattern is repeated annually as long as growth continues. Such a sequence appears to hold for Balanus balanoides (L.), B. balanus (L.) da Costa, B. crenatus Brug. and Verruca stroemia (0. Muller) (see BARNES, 1952-53, 1955 and 1958 a; BARNES and BARNES 1954; BARNES and POWELL 1953) at Millport, Scotland, and similar results have been obtained elsewhere (RUNNSTRbM 1925; HATTON and FISCHER-PIETTE 1932; MOORE 1934; HATTON 1938; BOUSFIELD 1954; CRISP 1954). When the effect of crowding, covering by mud or algae, and extent of intertidal exposure, are eliminated by semi-controlled raft exposures, the growth rate at any time of the year is seen to be particularly under the influence of the amount of food available. Food is particularly abundant during the planktonic phase and during the period when the young spat is growing vigorously. Indeed, it has been shown that in Balanus balanoides synchrony of nauplii release and the spring diatom outburst is achieved over the wide range of its distribution and the mechanism has been,

The rate of development of the embryos of Balanus balanoides (L.) from a number of european and American populations and the designation of local races

Abstract A summary is given of the distribution of Balanus balanoides (L.) and of earlier work on differences — racial and otherwise. The variation in the date at which different populations are fertilized is considered. Data are given on the time required for the development of the embryos of this species in vitro at 10 °C, with eggs from a number of populations from the eastern and western Atlantic and examined soon after collection, and also after transplantation and maintenance under ambient laboratory conditions over the next breeding season. Both aspects of reproduction are under genetic control. There is no correlation between the date of fertilization and the time required for development. Oocyte and egg size appear to be largely controlled by temperature. On both sides of the Atlantic there is a general tendency for the time of development to decrease with decreasing latitude. The population at Millport, Scotland appears unusual. The southernmost populations on European shores resemble those at the extreme south in North America. A study of the effect of temperature has shown that at lower temperatures the time of development of the embryos in vitro from all populations tends to be the same; the difference lies in the Q 10 values. The results are discussed relative to palaeontological data and the existence of clines in other features.

THE GENERAL BIOLOGY OF BALANUS BALANUS (L.) DA COSTA

as Maine on the east American coast and to the shores of Britain. While there is a good deal known about its distribution (see BROCH, 1924) with the exception of a recent study of its breeding habits in the Irish Sea -(CRIsP, 1954 there is little detailed information on its general biology. It is a common sub-littoral barnacle in the Clyde Sea Area, being found widely dispersed on suitable rough ground. It has been found at all depths down to 60 metres, and although more commonly between 20-30 metres, this may merely reflect the fact that it is at these depths that suitable substrata occur in this area. Observations have been made of its occurrence in the area, but the regular collections, on which this account is largely based, were taken between Little and Great Cumbrae at a depth of about 20 metres. The distribution does not appear to be regular even over quite a restricted area, but the population density at this point is very high (see later). Samples were taken with a small dredge, the stones and shells being usually covered with barnacles, often distorted from the typical shape because of overcrowding. The tidal currents at this point are quite strong, and this and the rough stony and shelly bottom appear to be excellent conditions for this species. On these grounds B. balanus is often, indeed usually, mixed with the other common sub-littoral cirripede in this area, B. crenatus. The other associated species are those commonly found on this type of mixed rough ground and the following list indicates those most commonly taken.

The morphology and histology of the cirripede pemis

The general morphology and detailed histology of the penis of two common boreo-arctic cirripedes, Balanus balanoides (L.) and B. balanus (L.) have been investigated. The penis is a highly extensible, annulated organ beset with four rows of sensory setae. The paired vesiculae seminales unite within the pedicel of the penis to give the single ductus. Distally, the exoskeleton is invaginated into this ductus. Circular muscles are present in the vesiculae seminales but do not continue into the penis. The histology of the ductus epithelium indicates a secretory nature as does that of a specialized group of cells, termed the ‘cushion’, towards the distal end: this group of cells is surrounded by circular muscle bands. Longitudinal muscles extend virtually the whole length of the penis; they give off fibres which are inserted at the junctions of the annulations. The muscles of the pedicel are described. Paired nerves in the pedicel give rise to four in the penis. The sensory innervation of the setae is described. The possible functional relations of the structure to the activities of the penis at copulation and during the emission of semen is discussed.