Methods for assessing the occurrence and recency of mating are important for the management and conservation of exploited brachyuran crabs. Using multiparous females of the snow crab Chionoecetes opilio, we evaluated by experiment the efficacy of three indicators of recent mating: a white deposit in the spermathecae, extended mate-guarding, and fresh grasping marks on the female pereiopods. This was done by contrasting sperm counts between the left and the right spermatheca of females that were exposed to males with the right gonopod ablated, at treatment sex ratios of 20[female]:3[male ] or 50[female]:3[male ]. We expected that sperm reserves would be balanced between the two spermathecae of non-mated females and larger in the right than in the left spermatheca of mated females. Although no mating indicator was infallible, the presence of a white deposit was the most accurate because it maximized the median difference of sperm counts between the two spermathecae for the group of presumably mated females and minimized it for the group of presumably non-mated females. The use of grasping marks overestimated the mating frequency and resulted in the misclassification of a large proportion of females. Extended mate-guarding was a slightly better mating indicator than grasping marks, but it is not practical for field studies. Classification errors associated with each indicator can be explained mostly by female and male behaviours and may vary in magnitude with sociosexual context.

This study compared the scaling of the glycolytic enzyme lactate dehydrogenase (LDH) and the Krebs cycle enzyme citrate synthase (CS) in the swimming muscle and tentacle tissue of the mesopelagic coronate scyphomedusa Periphylla periphylla in two populations living under different oxygen minimum layer conditions. The LDH and CS activities in these tissues of two other coronate scyphomedusae (Paraphyllina ransoni and Periphyllopsis galatheae) and the bathypelagic narcomedusa Aegina citrea were also studied. The scaling of these two enzymes along with total protein was investigated in whole organism homogenates of the surface-living scyphomedusa Aurelia labiata. Mass-specific LDH activities in swimming muscle showed positive scaling in relation to body size in Periphylla periphylla collected off California and Hawaii. Mass-specific LDH activities in tentacle tissue increased with regards to increasing mass only in specimens of P. periphylla collected off California. The LDH values of the scaling coefficient, b, in swimming muscle and tentacle were significantly higher in P. periphylla collected in the low oxygen waters off California than from those collected off the Hawaiian Islands in a higher oxygen environment. The LDH showed a significant decrease with body size in Aegina citrea swimming muscle and in Aurelia labiata whole animal homogenates. The largest species in this study, Periphyllopsis galatheae, had LDH activities similar to the smallest specimens of Periphylla periphylla. The results of this study suggest that the scaling of glycolytic activity is related to oxygen availability for P. periphylla. In Aurelia labiata, which is only exposed to episodic hypoxia, and Aegina citrea, scaling of glycolytic activity is not affected by oxygen availability.

Lindia gravitata, previously considered a synonym of L. tecusa by several authors is redescribed. Body shape and trophi structure show that both species are closely related, and unequivocally differentiated by e.g. toe shape, number of sensory papillae, and shape of subunci and epipharynx. Other related, but insufficiently described congeners are listed. The diagnostic features of the subgenus Halolindia are discussed.

The pilumnid crab Pilumnus limosus is known from Gonzaga Bay, Baja California, Mexico, to Zorritos, Paita, Peru. Larvae from a female collected in the intertidal rocky shore in Mazatlán, south-eastern Gulf of California, Mexico, were reared in the laboratory from Zoea I to megalopa. A complete description and illustration of larval features is provided and a comparison with closely related species showing known larval development is presented. As in most species of this genus, P. limosus larval development consists of four zoeae. All features observed in P. limosus are similar to those of P. reticulatus and P. sayi. All those larvae have lateral processes on abdominal somites 2–5 (2 or 3 in other species); posteromarginal denticles on abdominal somites 2–6 (absent in other species of the genus).

Specific rations for the zooxanthellae-bearing medusa, Linuche unguiculata, were calculated using two approaches: (a) gut contents of field collected medusae combined with experimental measurements of digestion time; and (b) experimental feeding studies combined with estimates of ambient prey biomass. Estimates of specific daily ration from gut contents averaged 5% for carbon, 6% for nitrogen, and 4% for phosphorus for the dominant size of medusae. Of the 868 medusae examined, 86% contained recognizable prey with an average of 3.6 items per medusa. Copepods dominated the gut contents (51%) as well as the ambient zooplankton prey (82%), but there was an over-representation of shelled prey, larval molluscs and foraminifera, in the gut (33%) compared with their availability (4%). Digestion times for crustaceans ranged from 1—4 h with longer times for larger prey. Ambient prey concentrations in areas of abundant L. unguiculata ranged from 0.2—4.0 prey l-1, with an average of 1.7 and no measurable day—night differences. There were also no measurable day—night differences in ingestion rates for field or laboratory fed medusae. Feeding studies showed a linear relationship between ingestion and prey concentration up to 400 prey l-1. Rations determined from experimental feeding studies were higher but less than double the ration estimates based on field gut contents. Specific ration decreased with increased medusa size in both field and laboratory results. Heterotrophy was calculated to be a major source of both nitrogen and phosphorus, but only a minor source of carbon. Elemental budgets for carbon, nitrogen and phosphorus were calculated using measured inputs of photosynthesis, ingestion, and dissolved nutrients and measured outputs of respiration, excretion, reproduction and tissue growth. Total measured outputs balanced the inputs, within the uncertainty associated with egg production.

Two new species of Munida (M. gordoni and M. grieveae) and one new species of Agononida (A. nielbrucei) are described from volcanic seamounts off northern New Zealand (RV ‘Tangaroa’, National Institute of Water and Atmospheric Research [NIWA], New Zealand). Description of new species and preliminary examination of NIWA collections reveal unusually high endemism of volcanic seamount populations of Galatheidae.

Cytotoxic activity of the mollusc Mytilus galloprovincialis haemolymph was considered as a possible marker of mussel health status. An easy-to-use and low-cost cytotoxicity test was set up to assess whether cytotoxicity is influenced by environmental stress such as an increase in water temperature or a reduction in water pH or salinity. Experiments demonstrated that, despite great variability in cytotoxic activity among the mussel populations, changes in the water physical conditions reduce mussel cytotoxicity, making animals more vulnerable to pathogen aggression.

four captive specimens of sandbar shark carcharhinus plumbeus from the l'oceanogràfic aquarium (valencia, spain) were studied: one adult female (192 cm total length [tl]) reared for five months, her two new born pups (a female, 61 cm tl and a male, 60 cm tl), and one juvenile female, born in captivity, dead at nine months of age (90 cm tl). comparative measurements of length and diameter of vertebrae from three different regions of the vertebral column showed that vertebrae above the pelvic fins (nos. 59–63) are the biggest in this species. consequently, these vertebrae are preferred for age estimation given that growth marks are easier to identify. the only present mark in the vertebrae of the two neonate specimens was at the edge and was interpreted as the birth mark. a mark at a similar distance was present in the vertebrae of the juvenile and adult females.

adult female vertebrae analysis shows 23 marks without any variation in the banding pattern distribution during free-range growth and short period of captivity. the juvenile individual shows two clear growth marks developed after birth. the presence of these marks in a 9-month old individual suggests that the counting of all vertebral growth marks as annuli may result in the overestimation of age for this shark species.

Reproductive patterns such as gonad maturation, production and release of gametes, fecundity and moulting play a major role in the continuity of populations and their adaptations to the environment they inhabit. The present study assesses the breeding cycle, moult activity and egg production in the hairy crab Pilumnus vespertilio, a typical inhabitant of intertidal pebble and rocky substrates of East African coasts. A total of 930 crabs was collected between January and December 2002 at Inhaca Island, southern Mozambique. Both oogenesis and spermatogenesis exhibit a continuous and synchronized pattern. Maturation of the female and male gonads occurs from early winter to mid summer and spawning is in summer. Moulting females showed two major peaks (January–March and October–December) whereas a single peak was recorded in males (October–December). Pilumnus vespertilio breeds continuously with high incidence in March and December and a strong decrease from April to July. Results revealed that both temperature and rainfall were positively associated with the relative abundance of egg-bearing females. The number of eggs carried by ovigerous females increased with size, ranging from 300 to 8000. The high reproductive activity of P. vespertilio may enhance larval survival and development, which guarantees juvenile recruitment in the study area.

A new species of cirrate octopod, Opisthoteuthis borealis sp. nov. is described from specimens caught at depths of 957–1321 m off the coast of Greenland. Opisthoteuthis borealis sp. nov. is the most northerly of the Atlantic species of the genus and can be distinguished from the other species by the form of the digestive gland and the arrangement of enlarged suckers on the arms of mature males.

Ctenophores are important members of planktonic communities that are often abundant in dysaerobic environments. Previous studies have shown that ctenophores are not adversely affected by extended periods of hypoxia. The three species used in this study, Pleurobrachia bachei, Bolinopsis infundibulum, and Mnemiopsis leidyi, were all able to oxyregulate to very low partial pressures of oxygen (PO2s). These species were found to have mean critical oxygen tensions of 7.7, 10.6, and 7.2 hPa respectively. In general, ctenophores are better oxyregulators than medusae and many species of shrimps, fish and squid. Intragel oxygen was measured using a fibre optic oxygen optode. All these ctenophores have intragel subsurface [O2]s of 5–10% below that of the surrounding seawater. Intragel oxygen measurements of P. bachei showed a gradient of decreasing PO2 from surface tissues to the gut. Specimens of P. bachei over 14 mm in diameter had anaerobic guts. Survival times in anoxia ranged from 0 h for M. leidyi to up to 6 h for P. bachei. Ctenophores rely on aerobic metabolism to tolerate hypoxia.

The rainbow pearl oyster Pteria sterna is distributed along the Mexican Pacific coasts and Gulf of Baja California, where it represents a great economic potential. Five sampled populations collected in Baja California were used to screen two mitochondrial DNA genes that have proven useful in population genetics studies of several other bivalve species. The lack of polymorphism detected in these samples suggests a recent event of very low population size, most likely a founder event, which is congruent with the absence of P. sterna in the fossil records in Baja California.

Laboratory breeding of the dog-whelk, Nucella lapillus, has established that the male-sterilizing Dumpton Syndrome (DS)—underdevelopment, or non-development (aphally), of the penis, incomplete formation (non-closure) of the vas deferens, resulting in a split prostate—can be readily observed in male F1 progeny. Cultivated under high ambient concentrations of the antifouling agent tributyltin (TBT), DS-carrying females can be recognized by their lesser degree of masculinization (imposex): sterilization is thereby avoided. When Dumpton females are crossed, under high ambient TBT, with individuals from a non-DS-affected population (Bude, North Cornwall) DS is absent from both sexes. Crosses of these F1 progeny result in F2 progeny exhibiting the classic DS symptoms in both sexes. A Mendelian mechanism for DS inheritance is suggested by the data.

one of 353 port jackson sharks, heterodontus portusjacksoni, caught off the southern coast of western australia, was a hermaphrodite. the female reproductive tract consisted of a large (functional) right ovary with three large yolked ova, a small non-functional left ovary and two well-developed uteri and oviducal glands. the male tract comprised two conspicuous but undeveloped testes, two vas deferens and two calcified claspers with grooves. this individual represents the first published example of hermaphroditism in the order heterodontiformes and is a rare example of an elasmobranch with a complete suite of both male and female reproductive structures.

A first trial to recognize gelatinous zooplankton using an immunochemical method was carried out. Polyclonal antibodies (rabbit IgG) raised against three cnidarians and four pelagic tunicates were purified and tested for their specificity against various sympatric zooplankton and micronekton. While antibodies to cnidarians were species-specific or at least distinguishable by means of the patterns of the bands appearing, antibodies to the pelagic tunicates cross-reacted with the antigen from the other tunicate species although these did not cross-react with other animal taxa. These results suggest that the present cnidarian antibodies can be applied to the predator identification at the species level. Antibodies to pelagic tunicates would also be effective tools for basic scanning at higher taxonomic levels, i.e. pelagic tunicates or other animals. The antibodies were applied to the identification of the ‘barrel’ of Phronima, indicating that the ‘barrels’ originated from tunicates but not from cnidarians. The present study indicates that the immunochemical method using polyclonal antibodies is a powerful tool for the detection of gelatinous zooplankton.

The reproductive cycle of the purple clam (Amiantis purpurata) northern Patagonian population was studied throughout a 19-month period (September 1993–March 1995) using standard histological techniques and quantitative indicators (oocyte diameter distributions, oocytes per ocular field and relative oocyte area). In this species gametogenesis is a continuous process involving a complete gonadal restitution after the end of the reproductive season (no resting period). The proliferation phase occurs during the coldest half of the year (April to September) and maturation takes place during spring (September to December). Several partial emissions of gametes, with subsequent restitution of the gametogenic series, occur during the summer months. During the total maturation stage, oocytes never filled the whole alveolar area: maximum per cent of alveolar sections occupied by oocytes (46%) was observed in late spring–early summer. Implications of the reproductive pattern in the context of palaeogeographic history of northern Patagonia, and the isolation of this population are discussed.

the reproductive biology of 1045 female (9.5–67 cm (total length (tl)) and 1007 male (9.4–64.3 cm tl) blackmouth catsharks, galeus melastomus, was investigated. the sharks were caught off southern portugal by bottom crustacean trawlers at depths from 209 to 754 m. the sex ratio was 1:1, and this species is sexually dimorphic with males approaching maturity at smaller size than females. sexual segregation appears to be given for the stock within the study area. sexual maturity was reached at a total length above 49 cm in males and above 56 cm in females. mating and egg-deposition take place all year round, with two reproductive peaks of activity, in winter and summer. egg capsules are, on average, 54 mm long and 21 mm wide, with a maximum of 63×25 mm encountered. morphometric measurements of claspers, testes, ovaries, and oviducal glands were suitable for determining sexual maturity of blackmouth catshark.

The population structure and fecundity of the hermit crab Dardanus deformis were studied. Monthly samples were obtained between January and December 2003 at Costa do Sol, Maputo Bay, southern Mozambique. A total of 604 individuals was analysed of which 273 were males, 164 non-ovigerous females and 167 ovigerous females. The overall size–frequency distributions were unimodal, with males reaching larger sizes than both ovigerous and non-ovigerous females. Females were slightly more abundant than males, but the overall sex ratio did not differ significantly from 1:1. Dardanus deformis showed continuous reproduction throughout the study period. A small number of juveniles was obtained, suggesting that recruitment may take place in a different habitat than that occupied by the adults. The egg number increased with female size, and the high incidence of ovigerous females, may suggest a higher reproductive activity probably as a result of the rapid embryonic development in the study area.

Shell growth of the whelk Nassarius (=Hinia) reticulatus was studied in the Ria de Aveiro (north-west Portugal) between 1995 and 1998. Temporal analysis of shell height frequency distributions demonstrated that growth occurs during the first five years of life, whelks attaining a size of 6·7–7·8 mm in the 1st year, 12·1–14·5 mm in the 2nd year, 18–19·5 mm in the 3rd year, 22·7–23·6 mm in the 4th year and by the 5th year males have achieved an average size of ∼25 mm whilst females have reached ∼27 mm. Age estimates from internal microscopic annual growth lines present in the shell lip suggest that large whelks may achieve a longevity of at least 11 years. External annual rings become less discernible as the whelks increase in size and estimates of their age based solely on ring counts can underestimate their age. In males sexual maturation is reached between the 3rd and 4th years whilst in females it is attained between the 4th and 5th years. Imposex was visible in ∼2 year old females and attained maximum development by the 5th year.

Leaf litter, pneumatophores, saplings and patches of macro-algae are common characteristics of habitats in mangrove forests. The amounts of these vary among different parts of mangrove forests. In Port Jackson, some parts of forests under the canopy of trees appeared to have more saplings, longer pneumatophores and greater amounts of leaf litter and macro-algae than did other similarly shaded parts of the forest. The former also appeared to have greater densities of snails, Ophicardelus spp. and Salinator solida, which was confirmed by quantitative sampling. Two field experiments were carried out, in which the amount of litter or algae and the length of the pneumatophores, were manipulated to test six alternative models about influences of these features of habitat that might explain these patterns. In each experiment, both species decreased rapidly in plots with reduced litter and showed no response to the length of the pneumatophores. In the first experiment, there was no response to reductions of algae, but in the second experiment, each species showed a decrease in density when algae were reduced. The implications of these rapid responses to changes in small-scale features of habitat are discussed with respect to managing disturbed habitats.