Annual reproductive cycles of two commercially important bivalves, the razor clam Ensis siliqua and the clam Venus striatula were investigated. Specimens of both species were sampled monthly from a site off Vilamoura, south of Portugal, between June 1992 and May 1993. Gonadal development was monitored using standard histological methods. Observed gametogenic progression was categorized by six stages: (0) inactive; (I) early active gametogenesis; (II) late active gametogenesis; (HI) ripe; (IV) partially spawned; and (V) spent. Both males and females showed a synchronism in gonadal development. The gametogenesis in the razor clam began in December and by late April the gonads were characterized morphologically by an abundance of ripe eggs and sperm. Partially spawned individuals were first encountered in May. All were spent by July. The gametogenic activity in V. striatula began in the months of October/November and continued until March. Spawning occurred between April and early August. Both species reached maturity during the first year of life.

The demography of a lagoonal population of Lipophrys pavo over a four year period is described. This population exhibited high variability in recruitment and mortality and as a result, in age structure and density. During the study the average size at a given age decreased. This decrease was not linked to growth variation. Changes in demography and length structure are interrelated and could be linked to stressful environmental conditions and to reproductive patterns of this species.

Lipophrys pavo (Risso, 1810) is a common species in shallow waters of the rocky littoral of the Mediterranean sea (Zander, 1972; Patzner, 1984). This species differs from other Blenniidae by its ability to colonize biotopes where hard substrates are scarce (Moosleimer, 1980; Almada et al., 1994; Ruchon, 1995), and by its great euryhaline and eurythermal tolerance limits (Marion, 1890; Paris & Quignard, 1971; Zander, 1972; Müller et al., 1973; Moosleitner, 1988; Patzner & Seiwald, 1988). This euryvalence has allowed L. pavo to colonize brackish and soft-bottom lagoons of the Gulf of Lion where it is the single Blenniidae present (personal observation). Lipophrys pavo is a gonochoric species exhibiting strong sexual dimorphism (Zander, 1975; Papaconstantinou, 1979). Males are territorial nest breeders during the spawning season (Patzner et al., 1986), and females are batch spawners (Fishelson, 1963a; Patzner, 1985a).

Three specimens of the giant squid Architeuthis were by-caught in demersal trawls to the west of Ireland, between April and June 1995. All three specimens were mature males, of mantle length 975–1084 mm. Although some intraspecific variation in fin, beak and gill were noticed, all three specimens were tentatively assigned to the species A. dux. The three specimens had food remains in their stomachs and food items identified included Micromesistius poutassou, Trachurus trachurus, Nephrops norvegicus and Eledone cirrhosa. Age estimates were made by counting putative daily growth increments in ground statoliths, and ranged from 294–122 d, giving percentage daily growth rates of 2·96–4·25% indicating a short life cycle and extremely rapid growth.

Most fertile individuals of the apodid sea cucumber Polycheira rufescens, living in the intertidal zone near Iso Marine Station in southern Kyushu, Japan, spawned on day one and two before every full and new moon in the period from the second half of July until August or October from 1983 to 1989, the month differing in different years. Synchronous spawning associated with the same phases of the moon was also observed at Sakurajima Marine Station near Iso in 1991. Individuals ready to spawn were divided into four sexual types: two sorts of hermaphroditic males with small or larger growing oocytes and males and females. Further investigation revealed that some individuals changed from male to female or from female back to male in the two week interval between spawnings. Moreover synchronous gametogenesis occurred in association with sex changes throughout the breeding season, the period from initiation of spermatogonia proliferation to spermatozoa release was three weeks, and the period from initiation of oocyte growth to egg shedding was about five weeks.

Cephalopod prey of several cetacean species from Hawaiian waters were identified and quantified from the beaks in stomachs of stranded individuals. The different species of cetaceans all appear to target different species and sizes of cephalopods. Beaks from two sperm whales (Physeter catodon) included a total of 312 upper and 292 lower beaks (mandibles) of cephalopods. All of the cephalopods represented by lower beaks were oceanic squid belonging to 20 or more species in 14 families. The major constituents of the whale diet were Histioteuthis hoylei (45% by number and 10·9% by dry weight), Ommastrephes bartrami (7·6% by number, 30·6% by weight) and Architeuthis sp. (only 0·7% by number, but 26·5% by weight). In a Risso's dolphin (Grampus griseus) stomach, 1051 upper beaks and 1349 lower beaks were present. Eighteen or more genera of cephalopods in 15 families were present. The major constituents of the Grampus diet were Enoploteuthis spp. (36·1% by number and 30·1% by dry weight) and Abraliopsis spp. (23·6% by number, but only 4·9% by weight) and O. bartrami (1·3% and 32·1% respectively). The melon-headed whale (Peponocephala electra) eats fish as well as cephalopods which are represented by only six lower beaks belonging to five genera, Enoploteuthis, Teuthowenia, Abraliopsis, Abralia sp. and Bathyteuthis abyssicola. The beaked whale (unidentified) contained two lower beaks which were O. bartrami. Stenella attenuata also eats fish and the sample contained lower beaks, one of Enoploteuthis sp. and seven of an Abraliopsis sp.

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.

Allozymes and restriction fragment length polymorphisms (RFLP's) in genes of the NADH dehydrogenase complex (ND 5/6 genes) of mitochondrial DNA (mtDNA) were used to investigate the spatial genetic structure of Atlanto-Scandian herring (Clupea harengus). Samples (sample size=46–50/site) comprised Icelandic summer spawners, Norwegian spring spawners, and two fjord populations, Balsfjord and Trondheimsfjord, on the Norwegian coast. Fifty enzymes were assayed, and samples were routinely examined at 18 enzymes comprising 28 putative allozyme loci. Significant genetic differentiation (P < 0.001) was detected between Trondheimsfjord herring and all other samples, with apparent genetic homogeneity among remaining samples, including the Balsfjord; a region shown previously to contain an allozymically distinct population. Herring from the Balsfjord were shown allozymically to represent the Norwegian spring spawning group, suggesting the presence of two stocks, a deeper resident spawning (Balsfjord) and a shallower, non-native feeding population (Norwegian spring spawning). Variation at the ND5/6 genes using six restriction enzymes revealed 96 composite haplotypes in 196 fish. Mean haplotype diversity was high (0.92), though nucleotide divergence between samples was small (highest=0.00029, between Trondheimsfjord and Balsfjord samples; lowest=0.00003, between Icelandic summer and Balsfjord samples). Monte-Carlo %2 analysis of haplotype frequencies revealed no significant geographic heterogeneity among samples, thus revealing a discordant pattern of genetic differentiation produced by allozymes and mtDNA markers. The detection of a genetically divergent population in deeper waters of the Trondheimsfjord supports the existence of distinct deep-water resident populations in the Norwegian fjords.

Octopuses (Eledone cirrhosa (Octopoda: Cephalopoda)) held in an aquarium were subjected to varying conditions of feeding and starvation to evaluate putative indices of feeding and growth. Specific growth rate (%d−1) was linearly related to feeding rate (% of the body mass d−1) in animals with a mean body mass of 250 g at 15°C. Maximum growth rates varied between > 2% d−1 (body weights < 300 g) to < 1% d−1 (body weights ≤ 900 g) but specific growth rates were not related to body weight. Growth rates became negative (weight loss) after one week without food.

The digestive gland index (DGI) was significantly correlated with short and long-term feeding and specific growth rates, and with body weight. Muscle RNA concentration was linearly correlated with growth rate during the previous 1–3 weeks but not with feeding rate. RNA:protein ratios were not different between mid-arm and mantle sample sites but arm tip values were significantly higher. RNA:protein ratio was related to body weight only in feeding animals. It is concluded that DGI is an index of feeding rate and that RNA:protein ratio can be used as an index of recent (~ 4 weeks) growth rate.

We examined recent arguments that leptocephali of the European eel, Anguilla anguilla, swim in an oriented manner, rather than drift, to reach the continental shelf of Europe and the Mediterranean Sea. There is a cline of increasing body length of leptocephali from south to north and from west to east from the Mid-Atlantic Ridge (30°W) to the continental shelf, which could represent migration from south-west to north-east, transport eastward at all latitudes, or increased growth rate with latitude. Evidence that this cline is a trend in age of arriving glass eels along the European coast, and that the duration of migration is less than one year, is weak. Ages reported in the literature for specimens from Morocco to The Netherlands were based on the unvalidated assumption that rings in otoliths were deposited daily. The assumption is unwarranted because of low metabolic rate and uncertainty of nutritional mode of leptocephali. If the assumption were accepted, calculated hatching dates of eels arriving at the European coast imply year-round spawning. Lengths of leptocephali in the Sargasso Sea at various times imply that eels spawn only in late winter and spring. Leptocephali contain tiny amounts of muscle, especially aerobic muscle for sustained swimming. They probably have insufficient capability to swim across the Atlantic in the less than 1–2 y reported by others.

A new South African species of the genus Chaperiopsis is described from material deposited in the Muséum National d'Histoire Naturelle, Paris. Chaperiopsis stephensoni is redescribed and figured from the original material.

The genus Chaperiopsis Uttley, 1949 is widely distributed in the southern hemisphere. Numerous species of this genus have been described in different works; notable amongst these are the works of Busk (1854, 1884), Kluge (1914), Uttley (1949), Gordon (1984), Hayward & Thorpe (1988), Reverter Gil & Fernández Pulpeiro (1995) and Hayward (1995). Some previous records of Chaperiopsis spp. from South Africa are included in the works of Jullien (1881), Busk (1884), O'Donoghue & De Watteville (1935), O'Donoghue (1957) and Hayward & Cook (1983).

This study provides the first quantitative description of the emetic reflex (vomiting) in the dogfish (Scyliorhinus canicula) by using veratrine HC1 (lOmgkg−1, i.p.), the sodium channel activator as a stimulus. Vomiting occurred within 10 min of injection. The most notable features of the response in the correct temporal sequence were: (i) head shaking with wide gaping of the mouth; (ii) lowering of the ventral buccal cavity and expansion of the pharyngeal cavity; (iii) contraction of the gill arches, the buccopharyngeal musculature and lowering of the jaw rapidly followed by the expulsion of gastric contents (pieces of fish). The expulsion sequence (ii and iii) took ~ 1 s. The significance of the vomiting reflex in the dogfish is discussed in terms of its protective function and as a component of normal feeding to periodically eject indigestible food residues.

The stomach of a female northern bottlenose whale, Hyperoodon ampullatus (Odontoceti: Ziphiidae) stranded at Hiddensee Island, western Baltic Sea, on 23 August 1993 contained 7465 cephalopod beaks (4934 upper and 2531 lower). The lower beaks were identified, their rostral lengths were measured and used to estimate size and mass of the cephalopods consumed by the whale. All lower beaks belonged to one species, the boreoatlantic gonate squid Gonatus fabricii (Cephalopoda: Teuthoidea) indicating a mean squid mantle length of 21·9 cm and a mean squid wet mass of 220·7 g. The total squid biomass in the whale's stomach represented by the lower beaks was 598·6 kg. Assuming that all upper beaks belong to G. fabricii, the squid biomass taken by the whale was estimated to be 1089 kg. Besides the beaks partly digested squid gladii, spermatophores and 15 specimens of the fish parasite Sphyrion lumpi (Crustacea: Copepoda) occurred in the stomach. No fish remains were found.

An unusual mass settlement event of the grouper Epinephelus merra occurred on the fringing coral reefs of Reunion Island (south-western Indian Ocean) in April 1994. This major event coincided with stormy conditions associated with the new moon period. The abundance of new settlers was surveyed for 45 days following settlement on both the reef flat and the back reef area of the coral reefs of St Gilles, La Saline and St Leu. Mean densities of settlers were higher on reef flats (maximum 474 ind/20 m2 at La Saline) than on back reef areas (maximum 156 ind/20 m2 at La Saline). Seven weeks later, densities of settled E. merra had drastically decreased, and did not differ with site and zone (18.5 ind/20 m2). Percentages of post-settlement mortality at that period ranged from 85 to 88% in back reef areas and from 93 to 95% on reef flats. A strong correlation between density of recruits and per capita mortality suggests density-dependent early post-settlement mortality for E. merra. The limitation of food resources and shelters, perhaps combined with an increase of diseases due to high population densities of settlers, was probably the main cause of mortality just after the mass settlement. Predation by reef fish, including cannibalism between settlers, is probably responsible for most subsequent mortality.

Growth in ophiuroids is highly variable, and with increasing size and age of an ophiuroid specimen more and more of the innermost growth rings on the vertebral ossicles become overgrown and hence invisible. Two approaches to estimate individual age of slow growing brittle stars using the high Antarctic species Ophionotus victoriae are compared. One method interprets natural growth ring readings as size-increment data, whereas the second method compensates for growth ring overgrowth by means of an iterative corrective approach. Preconditions as well as advantages and disadvantages of both methods are discussed.

The ontogeny of evasive behaviours was examined in Atlantic menhaden (Brevoortia tyrannus, Clupeidae) and bay anchovy (Anchoa mitchilli, Engraulidae), with supplemental data for scaled sardine (Harengula jaguana, Clupeidae). Predicted relationships between ecology and behavioural ontogeny were tested using the different patterns of inshore vs offshore habitat utilization displayed by these species. In two of the species, menhaden and anchovy, the roles of vision, mechanoreception, and audition in evasive behaviours were examined ontogenetically and compared to the morphological development of these sensory systems. Anchovy early larvae were more responsive to a predatory stimulus than were menhaden; sardine early larvae were intermediate in responsiveness. By the end of the larval period most individuals tested in all three species responded. These results matched the pattern predicted by larval habitat. Ontogenetic trends in reactive distance did not match predictions based on habitat for these species but instead appeared to be more dependent upon changes in sensory morphology. In menhaden, ontogenetic changes in responsiveness were more dependent upon neuromast proliferation and cephalic lateral-line canal formation, while in anchovy these behavioural changes were more dependent upon ontogeny of the retina. Auditory stimuli were not implicated for either menhaden or anchovy in responding to the stimulus used.

Throughout lactation, pups of pinnipeds regularly vocalize, including during interactions with their mother. In all studied species of otariids and in some phocids, these calls exhibit sufficient acoustic variation for individual recognition. As female grey seals Halichoerus grypus (Pinnipedia: Phocidae) often pup in dense colonies, and regularly leave their offspring alone to go to sea, the selective pressure for mutual vocal recognition between mothers and pups could be high. To investigate call variation in pups of this species, 170 calls of ten individual pups were analysed. Out of seven acoustic features studied, location of maximum signal strength, the number of harmonics and the frequency and strength of the fundamental show the highest individuality. However, the apparent infrequent use of pup calls during mother-pup reunions suggests that vocal signals may not play the major role in pup discrimination by female grey seals, as observed in other phocids which females do not vocalize to their pup.

The fish Hoplostethus mediterraneus is a bycatch of the deep-water trawling in the north-western Ionian Sea. Data on its life history traits were collected during twelve trawl surveys carried out at two month intervals, between August 1993 and July 1995.

A vertical distribution according to size was observed for this species. The year's young were recruited mainly during the spring-summer period. Sex-ratio changed by size with females larger than males. Mature specimens were found mainly between May and November with a reproductive peak during late summer.

Seasonal growth was detected in the otoliths; the maximum ages of 11 and 10 y were observed in females and males respectively. Von Bertalanffy growth parameters for the whole population were: L3C=287–08 mm, k=0–127 y, to=-2–131. No significant differences were detected between the growth patterns of the sexes. Overall growth perfomance depicted through size-distribution analysis was not significantly different from that obtained by otolith reading.

Estimates of natural mortality rate for the whole population ranged from 0–14 to 0–20. Population structure, growth pattern, age at first maturity and low natural mortality rate indicate a life history mainly constituted by k-strategy characters and regulated by density-dependent mechanisms.

This study sheds light on the evolution of aquatic and terrestrial feeding modes in vertebrates, using two aquatic turtles as models. The estuarine aquatic diamondback turtle Malademys terrapin has a feeding mechanism that is similar to the basic feeding mechanism of terrestrial tetrapods (jaw gape cycles incorporate slow opening, fast opening, fast closing and slow closing phases). Strikes upon prey also involve neck extension and cycles of the forelimbs. Malademys terrapin modulate their feeding behaviour and jaw action in relation to the nature of the prey item. Mussels are approached by walking on the substratum, and limb cycles are of small amplitude during the strike. Crabs, whether encountered in mid-water or on the substratum, are approached by swimming, and the strikes partly produced by vigorous upstrokes of the forelimbs, that occur simultaneously with neck extension. Crabs are dangerous prey, and the turtles often strike with the gape already at maximum, minimizing the time needed to bite a limb or other part of the crab. The tongue is not involved in food capture, but has a major role in food manipulation and transport prior to swallowing. Although transport cycles are similar to ingestion cycles, ingestion and transport are easily separable in the species. Malademys terrapin exhibit great distension of the throat during the strike, but this does not appear to generate adequate suction to aid capture of hard-shelled prey; it is suggested that throat distension reduces pressures in front of the advancing snout, thus preventing pressure waves displacing or alerting prey. The pelagic marine turtle Dermodielys coriacea, which specializes in gelatinous prey, relies heavily on suction for ingestion, which overlaps considerably with transport.

The present study examines the feeding habits of Alepocephalus rostratus, the only species of the family Alepocephalidae in the Mediterranean Sea and the second most important fish species, in terms of biomass, inhabiting the deep slope of the Catalan Sea. Samples were obtained at depths between 1000–2250 m. Diet was analysed for two different size-classes (immature and mature specimens) at three different bathymetric strata during two different seasons. The feeding habits of A. rostratus included a narrow range of mobile macroplanktonic organisms (e.g. Pyrosoma atlanticum and Chelophyes appendiculata) and some material of benthic origin. Pyrosoma atlanticum was the preferred prey item in spring at 1000–1425 m, being very scarce in summer at the same depth as a consequence of its scarcity in the environment during this season. There were some ontogenic differences in the diet of A. rostratus at 1425–2250 m. Adults ingested more and larger prey than juvenile specimens. The scarcity of resources below 1200–1400 m fostered a more diversified diet, as well as passive predation of sedimented material.

Fucus vesiculosus was transplanted from one locality with an impoverished flora to another with a species-poor but different vegetation. Discs of Fucus thallus incubated in culture showed a significant increase in epiflora in the transplants. The possible applications to routine monitoring of polluted estuaries are discussed.

Harmful effects of pollution on the algal biodiversity of estuaries have been reported in numerous floristic studies (e.g. Edwards, 1972). The species-list approach suffers from a number of quite serious flaws: it is highly labour intensive; the absence of sampling rigour makes it difficult to interpret the results; and it is unsuitable as a basis for routine monitoring. In order to overcome these objections, it was decided to see if Fucus vesiculosus L. (Algae: Fucophyceae) a perennial macrophyte with high tolerance to pollution, can function as a trap for spores of smaller algae in the same locality and so express, in some way, the species richness of the surrounding vegetation. The method adopted to test this idea was simply to transfer Fucus from one locality with an impoverished flora to another with a species-poor but different vegetation, and then to quantify the effects of transference on the diversity of the epiflora.