The bluefish, Pomatomus saltatrix, is quite abundant in the Gulf of Gabes, off the south-eastern coast of Tunisia. It is commercially exploited by artisanal gears and trawlers all year round, and by purse seine nets from May to August (bluefish fishery season). Catches of bluefish, in the period 1996–2004 fluctuated between 365.6 t and 1240.1 t with an annual average of 805 t. This fluctuation, partially due to the migratory nature of the species, could be also attributed to the fleet activities that sometimes changed at the mercy of the operators. The analysis of the virtual population of bluefish in the Gulf of Gabes showed that, in 2002, the stock that had just recovered rightly after an excessive fishing in 1996–1997 was again subject to a fishing effort that passed its capacity (E=0.71; E>0.5). The biomass (B) estimated to be ~2178.9 t only tolerated the extraction of 713.4 t (more or less one-third of B). However, the three fleets in use removed 1029.1 t with a yield per recruit (Y/R) of 70.5 g. As a result of this over-fishing, the actual stock of bluefish in the Gulf of Gabes was characterized by individuals having a mean total length of 17.88 cm, a size which is much lower than the one at first sexual maturity (23.5 cm). The turnover (D/B) being of 75.23%, it did not allow the reconstitution of the stock. The total removals (~1639 t) due to both natural mortality (M=0.28) and fishing mortality (F=0.675) had to be compensated especially by individual growth (1534.2 t; 93.6%) because of the low weight of the recruits.

Continuous monitoring by scientists and volunteers of the Biological Working Group of the Dutch SubAqua Union and the ‘Anemoon’ Foundation over the past four years, yielded a surprising six new records of sponges for Dutch coastal waters. Oscarella lobularis, Celtodoryx girardae, Suberites virgultosus, Haliclona (Haliclona) simulans, Halisarca aff. dujardini, and a species identified as Leucosolenia somesii were unknown from Dutch coastal waters before 2000. The latter is a giant calcareous sponge, seemingly belonging to the common Leucosolenia variabilis, but here assumed to be an invader as well, as it has spicular characters well outside the variation found in the majority of Dutch L. variabilis specimens. It is likely a member of a ‘forgotten’ species, L. somesii. Habit photographs, SEM images of the spicules, and for O. lobularis and H. aff. dujardini, photographs of histological sections are provided to substantiate these new records. With the exception of C. girardae, most of the species resemble previously described widespread north-east Atlantic species, occurring in the area to the south and west of the Netherlands, so it is assumed pending future genetic research that at least several of the invaders comprise range extensions related to rising winter temperatures. Possibly, recent shellfish imports may be an additional causal agent. We also report the occurrence of unprecedented spicular deviations observed in three sponge species commonly occurring in Dutch waters, Halichondria (Halichondria) panicea, Hymeniacidon perlevis and Haliclona (Soestella) xena, which grew in small inland water bodies. Possibly, the limited space in these inland waters with possible stress factors for sponges such as reduced water exchange, and deviating chemistry, have caused the sponges to form stunted growth in spicules varying from rhabds with rounded endings to silica spheroids. We provide an updated list of sponges found in Dutch waters and a list of suspected or proven invaders of Dutch waters.

Skulls of 153 porpoises from the Sea of Azov and the Black Sea were studied. Thirty-seven skull measurements were examined. Skull growth in porpoises can be divided into five periods. The greatest changes in growth patterns occur after the first weeks of life. A ‘relay effect’ in growth of some structures (e.g. rostrum) was observed. Individual variation usually increases when a given structure grows intensively; however, some structures are highly variable over the entire lifespan. Sexual dimorphism is demonstrated in most of the measurements in adult animals. Temporal variation is minor. Skull structures are characterized by six types of allometry; three of them demonstrate drastic changes of allometry during lifespan, thus requiring two allometric equations to describe them. Skull proportions change critically during the first weeks of life. Six groups of correlated measurements differing in the pattern of correlation links during ontogeny were identified. Three factors play the most important roles in forming the definitive skull proportions: correlation between adjacent structures, impact of total skull size and inclusion in a certain functional complex.

Drift-nets are known to result in high incidental catches of some cetacean species. Despite a UN moratorium on their use in the high seas and a ban in the Mediterranean by all European Union countries, including Italy (EC Reg. 1239/98), some fisheries continue to operate illegally. In 2002 and 2003 three line-transect surveys were conducted in the southern Tyrrhenian Sea around the Aeolian archipelago. These transects were designed to assess the presence, distribution and population size of cetacean species likely to be affected by accidental captures in this area. Data were only sufficient to estimate abundance for the striped dolphin. The best estimate (and first such estimate for this area) was 4030 individuals (CV=0.30, 95% CI=2239–7253) for May 2003. A rough estimate of striped dolphin by-catch, based on floating carcases, was calculated as 36 by-caught animals over a period of 12 days (CV=0.58, 95% CI=11–113). These results, although approximate, are a cause for concern. Conservation and management implications of the results are discussed.

The calcareous sponge Paraleucilla magna has been detected at different Mediterranean sites (Taranto, Porto Cesareo, Brindisi and Naples). Its record in well studied areas where several benthic surveys have previously been carried out suggests a recent introduction of the species into the Mediterranean Sea. Until now this sponge has only been recorded from the Brazilian coast. It shows different morphologies, varying from tubular to an irregular massive shape with several folds occurring on its surface. The colour is white-cream. The surface is smooth. The consistency is friable. The oscula are 10–20 mm in diameter and located at the top of tubular protrusions. The skeleton consists of cortical and subatrial triactines and tetractines, together with atrial triactines, differently distributed in the sponge body. Paraleucilla magna is abundant in eutrophic environments, where seasonally it may reach very high frequency values and large dimensions. It is resistant to pollution, but it is also able to live in clean waters. The inclusion of this species among Mediterranean alien invasive species is suggested.

This study provides the first compilation on age and growth of some delphinids in south-eastern Brazil (18°25′S–25°45′S). A total of 154 delphinids were reported: 44 Atlantic spotted dolphin Stenella frontalis; 36 bottlenose dolphin Tursiops truncatus; 26 ‘Brazilian’ common dolphin Delphinus sp.; 20 rough-toothed dolphin Steno bredanensis; 16 Fraser's dolphin Lagenodelphis hosei; 3 false killer whale Pseudorca crassidens; 3 unidentified Stenella sp.; 2 pantropical spotted dolphin Stenella attenuata; 2 short-finned pilot whale Globicephala macrorhynchus; 1 spinner dolphin Stenella longirostris; and 1 striped dolphin Stenella coeruleoalba. Age was estimated by counting the number of growth layer groups present in the dentine in 74.5% of the sample. The growth of 92 individuals of the first five species was determined by the Gompertz model to length-at-age data. Stenella frontalis—the oldest specimen was 23 y and the asymptotic length of 224.4 cm predicted by growth curve occurred at about 20 y; T. truncatus—the oldest specimen was 26 y and the asymptotic length of 301.3 cm predicted by growth curve occurred at about 20 y; Delphinus sp.—the oldest dolphin was 18 y and the asymptotic length of 215.9 cm predicted by growth curve occurred at about 5–6 y; S. bredanensis—the oldest specimen was 24 y and the asymptotic length of 258.1 cm predicted by growth curve occurred at about 10 y; L. hosei—the oldest specimen was 19 y and the asymptotic length of 231.2 cm predicted by growth curve occurred at about 7–8 y. Only age was estimated for the other species. The age-at-length data for S. frontalis, Delphinus sp., S. bredanensis and L. hosei were consistent, suggesting a good agreement with previous work on these species. For T. truncatus, the age at asymptotic length obtained in this study might be confirmed by increasing the sample size. The information currently presented will contribute to further life history research of delphinids on the western south Atlantic coast.

A detailed account of sponge knowledge in Greek antiquity is given on the basis of their records in the written documents of the historical periods it comprises. The analysis of the examined material revealed interesting information on various aspects of sponge biology, more or less consistent with their present scientific knowledge. The value of sponges for man at that time was evident in many of his activities, such as household, personal hygiene, pain relief, disease treatment, art and war enterprises. The significant role of sponges in medical practice is illustrated by the high number of their records in the medical works of the studied historical period. Furthermore, sponges appeared in legends, as well as in similes and metaphors that attributed their special qualities to human behaviour, various body parts or objects.

Cytokines are important cell mediators involved in immune responses. Their expression can be modulated by numerous factors, including stress. The aim of this study was to compare cytokine mRNA expression from harbour porpoises exposed to different environments. Blood samples were taken from two healthy porpoises living in captivity at the Fjord and Belt Centre Kerteminde, Denmark, and from four wild porpoises accidentally caught in Danish waters. Real-time RT-PCR was used to quantify the transcription of interleukin-(IL)-1β, IL-2, -4, -6, -10, tumour necrosis factor-(TNF)-α, transforming growth factor-(TGF)-β and the acute phase protein haptoglobin. This revealed downregulation of the pro-inflammatory cytokines IL-1β, IL-2, IL-6 and TNFα, and a switch towards the T-helper-cell-(Th)2- and Th3-cytokines, IL-4 and TGFβ, in blood samples of the wild-captured animals. This indicated a shift towards immunomodulatory cytokines. In addition, cortisol levels were increased in the wild-caught porpoises. These results are suggestive of stress-induced modulation of the immune responses in the accidentally caught animals. The current study indicates that the expression pattern of these cytokines and the estimation of the Th1- to Th2- and Th3-cytokine mRNA ratios might be a useful indicator to analyse the influence of stress on the immune system in harbour porpoises.

Sympatric species need to avoid pervasive competition to counter its suppressor effects. Dietary divergence and habitat partitioning are strategies for coexistence. Golfo Dulce is a tropical fjord located in the southern Pacific waters of Costa Rica. This embayment is characterized by the mixture of neritic and oceanic-like features. Sympatric populations of spotted and bottlenose dolphins share this particular marine ecosystem. To analyse the means of coexistence among both dolphin populations, an approach using the marginality and specialization indices of ecological niche factor analysis was used to establish separation between realized niches of both species. Habitat partitioning is sustained by difference in habitat use; bathymetry and topography separated both species' ecological niches. Dietary divergence could not be concluded because of lack of accurate dietary information. Nevertheless, it is likely to be separated by consumption of demersal prey by Tursiops truncatus, and pelagic prey by Stenella attenuata, accordingly with the differences in habitat use. Golfo Dulce could be perceived as an area of conservation importance: a geographical unit considered to contain special conservation values for both dolphin species.

Line-transect estimates of abundance generally assume that distances and angles to animals are measured without error. Biased distance measurements will lead to corresponding bias in abundance estimates. Efforts to address this have been made, but measuring distance to cetaceans at sea remains problematic. Four distance-estimation experiments were conducted to explore relationships between estimated and measured distance. Heteroscedasticity was found in all four cases. Preliminary evidence suggested that an observer differed in the ability to judge distance to fixed, continuously-visible cues and ephemeral, cetacean cues, which calls into the question the common practice of using marker buoys as cetacean proxies in distance-estimation experiments. Two studies found visual estimates to be positively biased, and two studies found reticule measurements to be negatively biased. Suitable correction factors were developed to address systematic bias from visual estimates, but these varied widely among observers and were sometimes non-linear. Errors in three studies showed positive skew, suggesting that ranges were overestimated to a larger degree than they were underestimated. If reticule and photogrammetric measurements yield log-normally distributed errors generally, then a least-squares regression will always overestimate the correction factor, underestimate range, and overestimate abundance. Photogrammetric methods to measure range to cetaceans performed well, and their use is encouraged. When measurements cannot be made to all sightings, however, it is recommended that experiments be conducted that generate sufficient sample size (of the target species, across typical survey conditions, and beyond the maximum range that most estimates will be made during the survey) to assess error distributions, examine evidence for non-linearity, and to consider inter-observer differences. Distance experiments, and training on survey protocols, can be conducted using ships of opportunity prior to the beginning of a dedicated survey, which would improve observer efficiency while reducing the costs of dedicated vessel time.

A method was developed to assist in the photo-identification of individual grey seals (Halichoerus grypus). Fixed reference points of the eye and ear were used to define a rectangular area of pelage on the seal's head, termed the identifier patch (IP). Extracted IPs were converted to binary masks, and the percentage of black pixelation within each mask was evaluated. Multiple images of the same head profile gave masks with similar patterns and percentage of black pixelation (mean standard deviation 3.3% (±1.6%)). The low level of ‘within seal’ variability enabled ‘between seal’ images to be separated on the basis of percentage of black pixelation. Subsequent matching was achieved by eye using the mask pattern to complete the identification process. Successful matching of seal images, collected two years and nine months apart, at a North Wales field site was accomplished using this method. Pattern-matching trials using 88 untrained volunteers showed the extracted black and white mask to be a superior visual cue for separating individual seals compared to straightforward inspection of photographs. All volunteers identified a greater number of correct matches using the mask-matching method. This method shows promise in providing a cheap and accessible system to order and search image databases.

The aim of this study is to investigate the possibility of using the tensile strength and the elasticity as two, among others, objective criteria for the evaluation of the quality and commercial value of two ‘Elephant Ear’ commercial sponges (Mediterranean and Philippine). These criteria could also provide additional taxonomic characters for the distinction of ill-defined species. The average tensile strength of the Mediterranean Elephant Ear was found equal to 2.88 ±0.19 kg cm-2 and that of the Philippine Elephant Ear equal to 6.88 ±0.77 kg cm-2 while the corresponding values for elasticity were 26.1 ±0.79% and 7.8 ±0.6%. This difference is related to the structure and arrangement of the spongin fibres as seen under the scanning electron microscope. The arrangement of the secondary fibres (very compact and regular structure) as well as the abundance and the orientation of the primary fibres (arrangement in the form of bars perpendicular to the external surface) give to the Philippine Elephant Ear a higher tensile strength value, a roughness to the touch and consequently inelasticity and stiffness. In contrast, the large number of smooth secondary fibres in the Mediterranean Elephant Ear, their loose arrangement and the limited number of primary fibres give to this sponge a higher elasticity and a smaller tensile strength value.

There is very little documentation on the economic importance of locally available marine sponges (Porifera) in north-western Europe. From Iceland and the Faroe Islands there are records of naming and using the so-called mermaid's glove sponge (Isodictya palmata) especially for cleaning purposes. As late as in the 1940s, school children in the Faroe Islands gathered this sponge and used it to clean the slate.

Using a large passenger cruise-ship (MV ‘Discovery’) as a platform, a cetacean survey was conducted between 1 August and 3 September 2005 across the northern North Atlantic Ocean and back, covering waters between the UK, Iceland, Greenland and Canada. The objective was to collect sightings data for all cetacean species encountered to begin to collate information for a large-scale sightings database. Two observers employed standard-distance sampling techniques and visual observations (naked eye) to scan for cetaceans during daylight hours and favourable weather conditions. Approximately 112 h were spent surveying over 23 d. A total of 13 cetacean species were encountered, with 173 separate sightings recorded, totalling over 2000 animals. The most commonly sighted species were minke whales (Balaenoptera acutorostrata: N=44), Atlantic white-sided dolphins (Lagenorhynchus acutus: N=34, with group sizes of up to 600), and humpback whales (Megaptera novaeangliae: N=31). The distribution of minke whales, Atlantic white-sided dolphins and fin whales was linked to underlying oceanographic variables. Overall patterns of distribution were consistent with our understanding of the summer distributions for the species encountered. The survey highlighted the cetacean diversity of the northern North Atlantic region. Repeat work using this methodology will allow an examination of species' distributions and estimation of their relative abundance.

In the present study, carried out in the Spermonde Archipelago, south Sulawesi, Indonesia, an assessment is presented of the farming potential of six sponge species (out of nine candidates considered) possessing pharmacologically promising compounds, i.e. Aaptos suberitoides, Amphimedon paraviridis, Callyspongia (Euplacella) biru, Hyrtios reticulatus, Ircinia ramosa and Pseudoceratina cf. verrucosa. A total of 350 cuttings was threaded on a polyethylene rope and attached to horizontal mooring structures at three experimental sites. Growth and survival were monitored for a period of six months and for some explants for an additional period of ten months. All cuttings were photographed at regular time intervals and growth was measured as increase in length and dry weight. With the exception of P. cf. verrucosa, survival rates were high (80–96%) during the mariculture period. Size increases were too little to be measured in A. suberitoides and P. cf. verrucosa cuttings. Significant growth was only observed for C. biru. The high growth potential and high survival rate of this sponge species suggest that it is a promising candidate for further mariculture development.

Most North Sea cetacean species are wide-ranging and consequently poorly studied. Spatial and temporal trends in the distribution of the harbour porpoise Phocoena phocoena, white-beaked dolphin Lagenorhynchus albirostris, and minke whale Balaenoptera acutorostrata were assessed at a coastal North Sea study area in Aberdeenshire, Scotland. Between March 1999 and October 2001, cetacean data were collected using both land- and vessel-based survey methods. A total of 174 sightings of these three cetacean species was recorded during approximately 330 h of combined survey effort (228 h land-based and 102 h vessel-based). Harbour porpoises were present throughout the year with peak occurrence during August and September. The presence of white-beaked dolphins and minke whales was strictly seasonal, with a peak in occurrence during August. The fine-scale distribution of all three species varied within the study area, with an apparent preference for sections of coast adjacent to deeper water. Most porpoise calves and juveniles were recorded between June and September, when 35% of harbour porpoise groups contained immature animals. The proportion of calves amongst porpoise sightings was higher during June than any other month. White-beaked dolphin calves were present in 32% of groups, and occurred in all three months that the species was recorded. Group size was higher in white-beaked dolphin pods containing immature animals. The strong seasonality in occurrence of all three species may relate to requirements for breeding habitat, movements of shared prey species and/or inter-specific competition with other species.

The palatability of organic chemical extracts from ten of the most abundant sponge species along the Israeli (shallow) coast, eastern Mediterranean Sea (Axinella sp., Axinella polypoides, Chondrilla nucula, Ircinia sp., Psammocinia sp. 1, Psammocinia sp. 2, Psammocinia sp. 3, Psammocinia sp. 4, Sarcotragus sp. and Tetilla sp.) was tested. To examine the generality of the phenomenon, it was evaluated with two types of potential predators, a fish and a gastropod. It was determined that the extracts of only two species (Psammocinia sp. 1 and Psammocinia sp. 3) deterred feeding of the omnivorous ornate Mediterranean wrasse Thalassoma pavo. On the other hand, extracts of five other sponges (Chondrilla nucula, Axinella sp., Ircinia sp., Sarcotragus sp. and Psammocinia sp. 2) were non-palatable to the omnivorous gastropod Strombus persicus (the extracts that deterred the fish did not deter the gastropod and vice versa). We also determined the capacity of extracts from six Red Sea sponges to deter T. pavo, and compared it with these extracts' effect on the Red Sea wrasse T. klunzingeri. All the extracts that deterred the Red Sea wrasse (from Amphimedon chloros, Crella cyatophora, Negombata magnifica and Theonella swinhoei) were also non-palatable to the Mediterranean wrasse. In addition to these four species, also Diacarnus erythraenus deterred Thalassoma pavo while being palatable to T. klunzingeri, whereas food pellets with extracts of Niphates rowi were eaten by both wrasse species.

The occurrence, distribution and structure of cetacean communities in the tropical South Atlantic beyond the shelf edge are poorly known with little dedicated research occurring within this region. At 15°58′S 005°43′W, the island of St Helena is one of the few areas of land within this region and the only one that lies in the tropical south-eastern Atlantic. As a result, St Helena offers a unique opportunity to study cetaceans within this area using small boats and land-based observations. This paper describes the results of a preliminary, short-term survey of the cetacean community around St Helena in the austral winter of 2003. Pan-tropical spotted dolphins (Stenella attenuata) were the most numerous species recorded, followed by bottlenose dolphins (Tursiops truncatus) and rough-toothed dolphins (Steno bredanensis), a species not previously reported from St Helena. This last species was only recorded occurring in mixed groups with bottlenose dolphins. Pan-tropical spotted and bottlenose dolphins differed in their spatial distribution around St Helena. While pan-tropical spotted dolphins were primarily recorded resting in large groups in the lee of the island during daylight hours, bottlenose dolphins and rough-toothed dolphins were recorded closer to shore and on both the windward and lee sides. Humpback whales (Megaptera novaeangliae) were also recorded once during the survey, but interviews with local fishermen suggest that this species regularly occurs in the waters around St Helena in small numbers during the austral winter. The results of this preliminary survey suggest that the cetacean community around St Helena during this survey was relatively simple, consisting of up to three species that are present year-round and one seasonally occurring species in the nearshore waters, with a small number of additional species occurring occasionally in deeper offshore areas.

In order to investigate seasonal changes in cetacean relative abundance, a series of surveys were conducted between the French mainland and Corsica. From February 2001 to February 2004, thirty similar transects were conducted monthly, using the same dedicated boat and a consistent sampling protocol, including visual observation and passive acoustic sampling. A total effort of 5759 km was sampled, conducted at the same speed and in good sighting conditions. Relative abundances of striped dolphins (Stenella coeruleoalba) and fin whales (Balaenoptera physalus) were determined using standard line-transect methodology. The relative abundance of striped dolphins peaked in May and September (>1.3×10-2 ind.km-1), while a consistent minimum value (<0.6×10-2 ind.km-1) was obtained from December to April. A maximum relative abundance of fin whales occurred in August with 5.6×10-2 ind.km-1 and decreased to almost zero from November to January. For sperm whale (Physeter macrocephalus), a long diver species, frequency and abundance indices were determined using acoustic sampling. The highest acoustic relative abundance was observed from August to October, with more than 2×10-2 ind.km-1. Environmental parameters (sea surface temperature and chlorophyll) were computed for the sampling area from remote sensing imagery and pooled on a monthly basis, to correlate with relative abundance indices of the three species.