This study describes the structure, growth, mortality and stock status of Litopenaeus schmitti in north-eastern Brazil. A total of 1169 specimens were captured (491 males and 678 females) from August 2011 to July 2012. Specimens were weighed and the length of carapace (CL) and total length were measured. The biometric relationships were estimated through regression analysis and growth was described through the von Bertalanffy model. Additionally, total mortality (Z), natural mortality (M), fishing mortality (F), length at first capture (Lc), maximum yield per recruit (ERMY) and longevity were determined. Females were larger (3.07 ± 0.51 cm) than males (2.68 ± 0.25 cm) and dominant in the largest CL classes. The biometric relationships for males, females and both sexes grouped showed a negative allometric growth. Females showed larger L∞ (asymptotic length) and k (coefficient of growth) (L∞ of 5.00–5.16 cm and k of 1.20–1.26 year−1) when compared with males (L∞ of 4.25–4.30 cm and k of 1.00–1.02 year−1). In general, the mortality of males (Z = 1.93–5.48 year−1; M = 1.59–1.61 year−1 F = 0.32–0.3.89 year−1) and longevity (1.11–2.16 years) were higher than those estimated for females (Z = 1.84–3.76 year−1; M = 1.70–1.77 year−1; F = 0.07–1.99 year−1; 1.07–1.78 years). Results indicated that L. schmitti stock is relatively close to the state of full exploitation. Moreover, the CL of first capture of females (2.44–2.51 cm) is below the length of first sexual maturation of the species. The lack of legislation governing shrimp fishing in the area makes this stock even more vulnerable.

There is great difficulty in maintaining aquatic mammals in captivity, since the attempt to replicate the environment they live in poses an enormous challenge. Poor captivity facilities without environmental enrichment can lead to different consequences for animal health, including the appearance of stereotypical movements. The aim of this study was to identify these behaviours in three groups of animals, one group of manatees inhabiting a reintroduction oceanarium in Pernambuco (PE) state, and two other groups confined in corrals constructed in natural areas (estuaries), one located in Paraiba state and the other in Alagoas state, all in north-eastern Brazil. Observations were conducted using the focal animal sampling method. It was found that the animals inhabiting the reintroduction oceanarium with no environmental enrichment showed stereotypical behaviour such as ‘Back-and-forth’ movements, ‘Hitting head against the limiting structure’ and ‘Hitting the muzzle’, while animals constrained within estuaries did not. The ‘circle swimming’ behaviour was present in a higher percentage of the animals captive in the reintroduction oceanarium, although no significant difference between the sites was found. The number and frequency of occurrence of stereotypical behaviours was significantly higher in animals kept in the reintroduction oceanarium in PE than in those of other locations. Based on these results we recommend the use of appropriate environmental enrichment and the reduction of time manatees stay confined in the reintroduction oceanarium.

Lumbrinerids are amongst the most abundant and diverse polychaete families in worldwide continental shelves, and have received attention recently through the description of several new species and new occurrences. Herein, a total of four lumbrinerid species are firstly reported in the eastern and southern Spanish continental shelf, extending their biogeographic distribution to the western Mediterranean Sea and increasing up to 25 the number of species known in the Iberian Peninsula coasts. New insights on taxonomy, ecological and biogeographic preferences and an updated taxonomic key for Iberian coasts and surrounding areas are also provided.

A series of experiments (1963) illustrates the stimulatory effect of 5-hydroxytryptamine on the bioluminescence of Thysanoessa raschii (M. Sars). A further series (1966) shows the effect of 5-HT and of the cinnamanilide anti-serotonin, Squibb 10,643, on the bioluminescence of Thysanoessa raschii and of small Meganyctiphanes norvegica (M. Sars), with and without stimulation by a bright light flash. The suggestion that 5-HT, or something chemically similar, may prove to be a part of the natural control system of the bioluminescence in these euphausiids is endorsed.

Molecular analysis has become a powerful tool in cetacean ecology since it supports efficient conservation policies. Remote biopsy sampling is the most efficient method to obtain epithelial material for analysis purposes; however, as an intrusive technique it presents inherent costs, evidenced by behavioural reactions. Clarifying which factors influence these responses is essential to assess its impact and prevent possible long-term effects. For eleven winters, samples from humpback whales were collected in the Abrolhos Bank, the main breeding ground of this species in the western South Atlantic. We analysed the influence of several characteristics of the shot, vessels, groups and behaviour on the frequency and intensity of the whales' response. The majority of biopsied whales did not show any detectable response. Among those that responded, a low-level category of reaction was most frequent. The use of larger boats resulted in less intense responses. Responses were influenced by group size and behavioural state: large groups, which were involved in aggressive mating behaviour, reacted less frequently than smaller groups. Females with calves showed less intense reactions than non-lactating females. The behaviour of the animals prior to and during the boat approach also affected their response: resting whales responded more intensely than whales involved in social or travel activities. Comparison with previous studies confirmed that reactions vary in intensity according to location: whales biopsied in feeding grounds responded with more intensity than those in breeding grounds, which in turn responded more intensely than whales in migration. This study reinforces existing evidence that biopsy sampling is unlikely to have long-term effects and can thus continue to be used as one of the main tools to access information which is vital for conservation.

A new hake species, Merluccius tasmanicus sp. nov., is described from New Zealand waters and another species, Merluccius australis is redescribed. Merluccius tasmanicus sp. nov. differs from all other congeneric species in the following combination of characters: upper profile of the head slowly concave; lateral line slowly concave in the caudal region; body depth 4.9–5.9 times in standard length (SL); orbital diameter 6.1–7.1 times in head length, 2.1–2.2 times in snout length and 1.6–1.9 times in interorbital width; second dorsal fin rays, 42–43; anal fin rays, 42–44; lateral line scales ∼164. Merluccius australis is redescribed to clarify the identity of this species. Merluccius australis differs from all other congeneric species in the following combination of characters: upper profile of the head straight; lateral line straight in the caudal region; body depth 6.6–7.1 times in SL; orbital diameter 4.5–5.4 times in head length, 1.2–1.7 times in snout length and 1.0–1.3 times in interorbital width; second dorsal fin rays, 40–43; anal fin rays, 40–43; lateral line scales, more than 155. Merluccius tasmanicus sp. nov. is found in New Zealand and Patagonian waters and occasionally in Japanese waters; Merluccius australis is reported in both New Zealand and Patagonian waters.

Changes in the planktonic cyanobacteria structure, composition and diversity were followed over three consecutive years (2005–2006–2007) in the Gulf of Gabes (Eastern Mediterranean Sea, Tunisia). Cyanobacteria abundances, biomasses and cell lengths were measured together with selected environmental variables (pH, salinity, temperature and nutrients). The space and time variations of the cyanobacteria in relation to the environmental factors showed a close relationship between these plankton communities and the hydrographic structure of the water column. Cyanobacteria developed over semi-mixed conditions (May–June 2006) and during the thermal stratification (July 2005). The cyanobacterial abundance and biomass was evident between 20 and 35 m in inshore stations and between 20 and 25 m in deeper stations during the semi-mixing conditions and stratification. This thermocline level coincided with the euphotic layer (21.85 ± 3.76 m) allowing access of light radiation. The cyanobacteria bloom occurred during May–June 2006 when the N/P ratio (<10) was clearly below the accepted standard molar ratio of N/P = 16/1. Commonalities among cyanobacterial genera include being highly competitive for low concentrations of inorganic P (DIP) and the ability to acquire organic P compounds. Our study showed that both diazotrophic (N2-fixing) cyanobacteria such as Anabaena sp., Chroococcus sp., Trichodesmium erythraeum, Spirulina sp. and Spirulina subsalsa and non-diazotrophic cyanobacteria such as Pseudoanabaena sp. and Microcystis display a great flexibility in the N sources which allow formation of blooms.

Two new gammaridean amphipods, Crybelocephalus birsteini sp.nov. and Halicoides discoveryi sp.nov., and a new subspecies of hyperiid amphipod, Scina wagleri atlantis subsp.nov. are described from oceanic plankton samples taken off Fuertaventura, Canary Islands.

Several previous authors have shown that the food of the mackerel, when in coastal waters, is of two different kinds, and that the fish adopts two distinct methods of procuring it. In the first place it feeds by a system of filtration upon planktonic organisms, and secondly upon prey of a larger character which is hunted by sight.

The urine secretion of the kidneys of Lophius piscatorius perfused with heparinized Lophius blood is very sensitive to perfusion pressure below a critical level, above which it becomes insensitive. The response of the urine flow to pressure takes the form of an exponential curve.

The blood flow through the kidneys, while rising slowly at pressures of about 20–30 mm of water, responds arithmetically to pressure above such levels.

At present it is impossible to make out whether pressure or blood flow has the greatest influence on secretion.

Water secretion in the aglomerular kidney is an active process. The oxygen consumption of the Lophius kidney is unmeasurably low, yet remains a possible factor in secretion.

During the period from April to September for the years 2014–2016, 998 swordfishes caught by the Moroccan artisanal longline fishery in the Strait of Gibraltar were sampled to study the reproduction of this species in this mixing area between the Mediterranean Sea and the North Atlantic. The results showed that the sex ratio is slightly in favour of males for sizes smaller than 130 cm LJFL (Lower jaw-fork length), whereas females are more numerous in sizes larger than 140 cm LJFL. Fifty per cent of females were estimated to be mature at 170 cm LJFL, while for males, the size at first maturity was estimated to be 95 cm LJFL. The swordfish spawn from June to September, probably in the Mediterranean Sea. The findings of this study suggest that the reproductive characteristics of swordfish caught in the Strait of Gibraltar are similar to those of the Mediterranean swordfish, and a high mixing rate between the Mediterranean and the North Atlantic stocks occurs in the study area.

Morphological abnormalities were observed in a population of the stauromedusa Haliclystus auricula in southern Chile. A total of 144 abnormal specimens was observed out of 3790 Stauromedusae sampled. The following abnormalities are described: individuals lacking arms (73%), with more than eight anchors (11%), more than eight arms (8%), lacking anchors (4%) and one individual with tentacles in abnormal locations. An individual with two peduncles, one with two mouths and one twin-like individual are recorded for the first time in this species. Their possible causes are discussed.

Direct observations on the reflecting layers in the tapetum of the spur dog Squalus acanthias confirm the orientations of the tapetal reflecting cells which were previously found histologically (Denton & Nicol, 1964). Surface views of the tapetum show the outlines of the exposed surface of the tapetal plates as ‘polygons’. The long axes of these polygons are parallel with the plane of the tissue on which they lie and the polygons are only inclined to this plane across their short axes. The angle to which they are inclined increases as we move towards the periphery of the eye.

A review of the literature indicated a lack of quantitative data on cell division in macroscopic algae in the laboratory and particularly in situ. By means of SCUBA techniques selected red algae were collected from their in situ location on a 24 h basis through the seasons of the year. The varied oceanographic and meteoro-logical conditions on the southern tip of Vancouver Island provided shore habitats of adequate contrast. Rhodomela larix was found to be a suitable test species for quantitative work, and differentials in mitotic activity in the growing parts of this plant were explored. Using squash techniques a method of quantitative estimation of mitotic activity employing a point-counting method was developed. It was found necessary to define the limits of mitotic phases in R. larix to facilitate quantitative analysis which was carried out over 24 h periods both in July and in February. Mitotic activity in R. larix showed a well-marked periodicity, although only the July data are statistically significant. The distribution of mitotic activity throughout the day was similar both in July and in February despite the dissimilarity of photo-period, temperature and tidal factors, which suggests the presence of a circadian rhythm. This preliminary work is being continued by further in situ investigations correlated with laboratory cultures under controlled environmental conditions.

This is the first study of the metabolic enzyme activity and energy state of the dwarf oyster Ostrea stentina (Payraudeau, 1826) in Tunisia and in the Mediterranean region. The main purpose of this study was to examine the modulation of the physiological status of the oyster O. stentina depending on the season and the presence of parasite Marteilia refringens. The prevalence of bonamiosis and marteiliosis were established by PCR. Bonamia exitiosa was detected only in 2.91% of oysters while the prevalence of M. refringens was 100% (30 Ind./30) in February and 93.93% (28 Ind./30) in March. A 42–87% mortality rate was reported during the study period. Biochemical analyses were carried out to evaluate the management of the energy resources in regard to the biochemical changes of lipids and carbohydrates. The enzyme activity of pyruvate kinase (PK), citrate synthase (CS) and cytochrome c oxidase (CCO) were measured and the mean level of enzyme activity was respectively 20.31 mU mg−1 protein; 12.06 mU mg−1 protein and 3.59 mU mg−1 protein. Carbohydrate contents of O. stentina were very low all year round with an average of 15.18% in dry weight, and lipid contents remain similar (11.77% in dry weight) compared with the values reported for most other temperate bivalves. Enzyme activity significantly decreased over time (P < 0.001). The energy resources of the oyster O. stentina wherein much of the energy was devoted to reproduction seem to affect the defence system.

Cultivation of the geoduck Panopea zelandica (Quoy & Gaimard, 1835) requires knowledge on embryonic development to produce spat in hatcheries. This study investigated the development of P. zelandica embryos at 15°C and 35 ppt and the optimal sperm:egg ratios for fertilization under hatchery conditions. Panopea zelandica broodstock were induced to spawn by serotonin injection. Sperm and eggs were collected and fertilization was conducted at sperm:egg ratios of: 50:1, 100:1, 500:1, 1000:1 and 10,000:1 over 40 min. The optimal sperm:egg ratio was <500:1 and the normal embryo yield at 3 and 18 h post-fertilization (hpf) ranged from 83–96%. Panopea zelandica eggs (~80 μm diameter) developed the first and second polar bodies within 15–20 and 50–55 min post-fertilization, respectively. The blastula appeared at ~8 hpf, including the XR and XL cells and the presumptive shell field depression. Gastrulation occurred at 12–18 hpf with organic material apparent at the shell field depression. The mid-stage trochophore, which appeared at around 35 hpf had an apical plate with an apical tuft. The shell field spread to form the periostracum, which expanded and folded into right and left segments covering the late trochophore. The early D-stage veliger appeared at 45 hpf with the soft body being enclosed by two valves and the appearance of the velum. These observations will serve as the basis for future analyses of P. zelandica embryogenesis and for optimization of commercial production of D-veliger larvae.

The present paper investigates standing stock variations of Halimeda opuntia on a sandstone reef of the South-west Atlantic Ocean, in order to better understand the role of this seaweed as a CaCO3 producer. The study was conducted over two 3-month periods, using photo quadrats to analyse the coverage area, and destructive sampling to quantify area-specific biomass and CaCO3 percentage. The alga occupied 2.4% of the substrate (4464 m2), growing as clumps with an average biomass of 1.59 kg m−2, resulting in a standing stock of 7097.8 kg of alga. This standing stock varied with environmental conditions, particularly wind speed. Assuming an exponential model for these variations, H. opuntia produced at least 13,050.14 kg (54.37 g m−2 day−1) of carbonate sediments. There was a positive correlation between changes in standing stock and coverage, but not with area-specific biomass. This suggests that net algal growth results in the occupation of new spaces, with minimal increases in height or segment density. Therefore monitoring coverage should complement traditional individual-based methods for estimating Halimeda growth and production. Combined, these approaches should result in more accurate models of the role of this alga on marine carbonate budgets.

The present study investigated the effects of a fish weir, a fixed trap used by artisanal fisheries, on the intertidal macrobenthic infauna of a macrotidal sandy beach on the Amazon coast. Biological and sediment samples were collected from within the weir and at five points of increasing distance (10 cm, 50 cm, 1 m, 2 m, 5 m and 50 m) from the external portion of the trap. The sediments from the weir and at 10 cm were dominated by mud, with a gradual decline in fine grains, water content and organic matter with increasing distance from the weir to 50 m (control). Taxon abundance and richness were significantly higher in the weir and at 10 cm than at the other sampling points. There was a trend of decreasing density and richness of the infauna from the weir to 1 m (which was a point of transition between the muddy and sandy sediments), after which the biological descriptors tended to increase once again. A shift was also observed in the dominant trophic groups, with a decrease in the abundance of the deposit feeders with increasing distance from the weir. By contrast, predators were more abundant at the points further from the weir. Our results indicate that fish weirs alter the associated sedimentary habitats, due to the increased protection from the action of waves and currents, with a micro-scale (from a few centimetres to 1–2 m) influence on the local macrofauna.

A species of balanomorph barnacle with solid plates and basis, Solidobalanus fallax, is recorded for the first time in the English Channel off Plymouth, at 44–56 m depth. It occurs exclusively on the valves of the queen scallop, Aequipecten opercularis. Only one out of 15 scallops carries the barnacle. Morphological details of the species are re-described in comparison with Balanus crenatus and B. spongicola, with which it co-occurs. Solidobalanus fallax ranges from Angola through West Africa and Morocco to Algeria but has not been reported previously from Europe. Some specimens were incubating embryos in late May, indicating a potential for local recruitment. Solidobalanus fallax is unlikely to be a recent immigrant but its abundance may have increased as a result of changing climate.

An investigation of the oil spill after the wreck of the tanker ‘Erika’ on 16 December 1999 showed that the maritime area around the town of Le Croisic (between the Vilaine and Loire river estuaries) was severely contaminated by the resulting black tide. Samples of sediment, oil and water were collected during several missions to the Le Croisic headland and analysed. The toxicity of the oil was tested on two organisms, the harpacticoid copepod Tigriopus brevicornis and the alga Enteromorpha intestinalis. The tests showed only slight degradation of the oil after three months. In laboratory conditions, the toxicity of the sediment contaminated by the oil was apparent on the copepod after four days of exposure. Seawater in contact with the oil also had an effect on the alga.