Summary atlas of deep-living demersal fishes in the North Atlantic Basin

Data from 9 major trawling surveys made around the North Atlantic Basin at slope, rise and abyssal depths provide directly comparable information on deep demersal fish distribution and faunal composition. 338 species in 57 families and 189 genera are recorded, and semi-diagrammatic maps showing relative abundance both horizontally and vertically for 67 of these are presented. Alepocephalidae, Gadidae, Macrouridae, Moridae and Ophidiidae comprise nearly 2/3 of all species taken. 296 species were taken at slope depths (200–2250 m), 99 at rise depths (2250–4500 m), and 32 at abyssal depths (>4500 m). Diversity and the rate of endemism were highest on the slope. The Norwegian, Caribbean and Mediterranean Basins appear to harbor impoverished versions of the adjacent Atlantic Basin fauna. Each species distribution appeared to be rather exceptional and no repeatable pattern could be found amongst the maps.     

Rissoidae (Mollusca: Gastropoda) from northeast Atlantic seamounts

The gastropod family Rissoidae is revised at the species level for the Lusitanian seamounts, situated between Portugal and Madeira, and the Meteor group of seamounts, situated south of the Azores in the northeast Atlantic Ocean. Based on material obtained by dredging and trawling, 48 species are reported, of which 30 are described as new. There is very little overlap between the assemblages found on both groups of seamounts, with only two shared species. On the Lusitanian seamounts, 24 species were collected. Seven species (six with planktotrophic development) are shared with the mainland shelf or slope and are represented in low numbers. Eleven species are endemic to this seamount group as a whole and of these, three account for 75% of individuals. Of the species not shared with the mainland, only one is found on the four seamounts, eight (three new) are found on two or three seamounts and/or neighbouring islands, and six (all new) are endemic to a single seamount. On the Meteor group, 26 species were found, of which five are shared with the Azores and 20 (all new) are endemic to the seamount group as a whole. Most species are found on only two or three seamounts, whereas nine species are endemic to only one of the seamounts, and of these five are concentrated on Atlantis seamount. Eight endemic species of the Meteor group included in Porosalvania n. gen. have very different shapes and occupy discrete bathymetric intervals, but are best interpreted as a local radiation originating from a relatively old colonization of this seamount group. The endemic species, and among them the successful ones, all have a paucispiral protoconch denoting non‐planktotrophic development. As in the Macaronesian archipelagos, the Rissoidae are the most species‐rich molluscan family on the northeast Atlantic seamounts.     

Feeding ecology of the giant otter (Pteronura brasiliensis) and the Neotropical otter (Lontra longicaudis) in Jaú National Park,Amazon, Brazil

This study compares the diets of the giant otter and the Neotropical otter, two Lutrinae species which feed mainly on fish. The study was carried out through the analyses of faecal samples collected between 2006 and 2008 (82 giant otter and 75 Neotropical otter) in the Jaú National Park. The giant otter feeds mainly on Cichlidae, Erythrinidae and Characidae, while the Neotropical otter consumes Doradidae, Loricariidae and Cichlidae. The two otter species had low diet similarity (Pianka’s Index = 0.16). The giant otter consumed larger fish than the Neotropical otter, which probably explores shallow river parts in search of small catfish. Prey other than fish were more frequent in the diet of the Neotropical otter, whereas giant otters ate a greater diversity of fish families. Increasing knowledge of the feeding habits and interactions of these two top-order predators is vital to determine appropriate protection and management policies.     

Saproxylic beetles (Coleoptera) and hoverflies (Diptera: Syrphidae) from a Mediterranean forest: towards a better understanding of their biology for species conservation

This report represents the first integrative study on saproxylic Coleoptera and Diptera Syrphidae from a representative Mediterranean forest in Cabañeros National Park in Central Spain. We collected 107 beetles, representing 32 families, and 25 species of hoverfly. Two undescribed and numerous rare beetle species were recorded, as were four hoverflies considered to be threatened species in Europe. We compiled biological information for all of the taxa encountered and recorded new data on their feeding habits, breeding microsites, and known tree associations. We found that the saproxylic biodiversity in this National Park was characterized by a significant number of Central European and North African species. Our results on the saproxylic assemblage, comprising many rare and poorly known species, of a typical Mediterranean forest represent a first step toward improved understanding of the saproxylic community and establishing the basis for conservation strategies in this region.     

Mapping aquatic faunal exchanges across the Sunda shelf,South-East Asia,using distributional and genetic data sets from the cyprinid fish Barbodes gonionotus (Bleeker, 1850)

The islands of Sumatra, Java and Borneo and mainland South-East Asia are encompassed by a shallow marine shelf, the Sunda shelf. The striking faunal similarities between countries bordering the Sunda shelf have been attributed to faunal exchanges across the shelf during Pleistocene glacial maxima when sea levels fell by up to 120 m and the shelf was exposed and drained by large river systems which connected many of today's rivers. The widespread distribution of fish species reflecting extensive faunal exchange across the area is predicted to be observed within species through the broad geographic distribution of genetic lineages. Here I report a discontinuous species distribution across the region for the cyprinid fish, Barbodes gonionotus. Mitochondrial DNA control region sequence and nuclear locus data from populations sampled across the species range, suggest that the present species distribution largely reflects faunal exchanges early in the Pleistocene and that these two regional population groupings have subsequently diverged in isolation. However, the mtDNA data present some evidence for limited genetic dispersal during more recent Pleistocene low sea levels. These results broadly confirm previous work from a catfish species and suggest that freshwater faunal exchanges may have been limited across the region during the Pleistocene despite extended periods during which the Sunda shelf was exposed.     

Alien polychaete species (Annelida: Polychaeta) on the southern coast of Turkey (Levantine Sea,eastern Mediterranean), with 13 new records for the Mediterranean Sea

The examination of benthic material collected from different depths and habitats along the southern coast of Turkey (Levantine Sea, eastern Mediterranean) in September and October 2005 revealed 30 alien polychaete species belonging to 15 families. Thirteen species (Pisione guanche, Linopherus canariensis, Onuphis eremita oculata, Lumbrineris perkinsi, Dorvillea similis, Timarete caribous, Pherusa parmata, Pherusa saldanha, Streblosoma comatus, Polycirrus twisti, Laonome triangularis, Branchiomma bairdi and Janua steueri) are new to the Mediterranean fauna, 24 species are new to the Turkish fauna and 27 species are new to the Levantine coast of Turkey. The specimens collected from the Levantine coast of Turkey and northern Cyprus that were previously identified as Linopherus acarunculata and Branchiomma boholense are reidentified as L. canariensis and B. bairdi, respectively. In the light of present knowledge, the previous reports of Lumbrineris inflata and Streblosoma hesslei from the Mediterranean (Italian coast) could refer to the species L. perkinsi and S. comatus, respectively. The species new to the Mediterranean Sea are redescribed and discussed.     

Aquatic vertebrate assemblages of the Upper Clear Creek Watershed, California

We sampled streams in the Upper Clear Creek Watershed in northwestern California in fall 2004 and fall 2005 to document assemblages of aquatic vertebrates and to provide resource managers with information on the importance of these assemblages in terms of regional biodiversity. We used single-pass backpack electrofishing to sample 15 sites in fall 2004 and the same 15 sites plus 4 new sites in fall 2005. We captured 10 fish taxa and 2 species of larval amphibians. Seven of the fish taxa were native species. Of the exotic species, only brook trout ( Salvelinus fontinalis ) occurred at more than 1 site. Ordinations by nonmetric multidimensional scaling indicated a gradient from sites with rainbow trout ( Oncorhynchus mykiss ), Pacific giant salamander ( Dicamptodon tenebrosus ), and tailed frog ( Ascaphus truei ) to sites dominated by riffle sculpin ( Cottus gulosus ), California roach ( Hesperoleucas symmetricus ), and Sacramento sucker ( Catostomus occidentalis ). The gradient in species composition was associated with changes in elevation, gradient, discharge, and substrate. The Upper Clear Creek Watershed represents a unique area of overlap between the North Coast California amphibian fauna and the Central Valley fish fauna with a notable paucity of exotic fishes and amphibians. Preservation of the integrity of native aquatic assemblages is an important goal for aquatic resource management in the region; our results provide a critcial baseline to gauge future management actions.     

Fish assemblage structure following impoundment of a Great Plains river

Understanding the upstream and downstream effect of impoundments on stream fish assemblages is important in managing fish populations and predicting the effects of future human activities on stream ecosystems. We used information collected over a 41-year period (1960-2001) to assess changes in fish assemblage structure resulting from impoundment of the Laramie River by Grayrocks Reservoir. Prior to impoundment (i.e., 1960-1979), fish assemblages were dominated by native catostomids and cyprinids. After impoundment several exotic species (e.g., smallmouth bass [ Micropterus dolomieu ], walleye [ Sander vitreus ; formerly Stizostedion vitreum ], yellow perch [ Perca flavescens ], brown trout [ Salmo trutta ]) were sampled from reaches upstream and downstream of the reservoir. Suckermouth minnows ( Phenacobius mirabilis ) were apparently extirpated, and hornyhead chubs ( Nocomis biguttatus ) and common shiners ( Luxilus cornutus ) became rare upstream of Grayrocks Reservoir. The lower Laramie River downstream from Grayrocks Reservoir near its mouth retains habitat characteristics similar to those prior to impoundment (e.g., shallow, braided channel morphology) and is the only downstream area where several sensitive species persist, including suckermouth minnows, hornyhead chubs, and bigmouth shiners ( Notropis dorsalis ). Grayrocks Reservoir serves as a source of exotic piscivores to both upstream and downstream reaches and has altered downstream habitat characteristics. These impacts have had a substantial influence on native fish assemblages. Our results suggest that upstream and downstream effects of impoundment on fish assemblage structure are similar and that downstream reaches which retain habitat characteristics similar to pre-impoundment conditions may serve as areas of refuge for native species.     

Bathyal cumaceans of the Catalan Sea (North-western Mediterranean): faunistic composition,diversity and near-bottom distribution along the slope (between 389 and 1859 m)

Deep-water epibenthic/suprabenthic species of Cumacea were studied in the Catalan Sea (Western Mediterranean). Samples (21) were taken at depths from 389 to 1859m, using a Macer-GIROQ type sledge, 32 cumacean species were collected. Diastyloides serratus and Leucon longirostris were the commonest species on the upper slope and middle slope, respectively. On the lower slope (1250–1859 m) dominance by any single species was not apparent and Cyclaspis longicaudata, Procampylaspis bonnieri and Platysympus typicus were the most abundant species. Two leuconids (Leucon cf. serratus, and Leucon (Crymoleucon) sp. A) were recorded for the first time in the Mediterranean Sea. The highest total abundance of cumaceans was encountered over the middle slope. Highest values of species richness and diversity (H') were registered at intermediate depths on the lower slope (1250–1355 m). The low H' value on the middle slope was attributable to the dominance of L. longirostris. Swimming coefficients calculated from near-bottom samples revealed intraspecific differences in the most abundant species. Thus, while mancas, juveniles, immature males and females, and adult females were captured almost exclusively in the lower level of the sledge, adult males of L. longirostris swam in the water column indistinctly between 10 and 140cm above the bottom. Similar trends, although less evident, have been established for other deep-sea cumaceans.     

First record of Monobrachium parasitum Mereschkowsky, 1877 (Cnidaria: Hydrozoa) from Brazil,in the tropical southwestern Atlantic,and its implication for bipolarity concepts

Project HABITATS was recently initiated in the Campos Basin (20.5–24° S), state of Rio de Janeiro, to assess biological impacts of petroleum exploration and exploitation on the continental shelf and slope of Brazil. Among species discovered in benthic samples from the area is the hydroid Monobrachium parasitum Mereschkowsky, 1877, occurring in an epibiotic association with the pelecypod mollusc Mendicula ferruginosa (Forbes, 1844): this is the first report of an association between the two species. Monobrachium parasitum has always been reported from cold waters, and is generally considered bipolar. This report records the occurrence of M. parasitum at lower latitudes, where they have seldom been collected: it is also the first account of this species from South America and the southwestern Atlantic. Moreover, the bathymetric distribution of M. parasitum is extended to a depth of 998 m. No previous records exist of hydroids from the Brazilian continental slope.     

Spatial and temporal distribution of breeding anurans in streams in southeastern Brazil

Anuran communities were studied at eight permanent forest streams located in a preserved site in southeastern Brazil, from August 2003 to October 2004. Nineteen species were recorded in six families: Bufonidae (two), Centrolenidae (one), Cycloramphidae (one), Hylidae (12), Hylodidae (two), and Leiuperidae (one). Twelve species exhibited calling activities during the study period and 10 of these were assumed to be reproductively active. The number of species present in streams was negatively related to stream volume. The composition of anuran assemblages was related to stream volume and structural complexity of the streamside habitat. Levels of dissimilarity between anuran communities from different streams were not related to the geographical distance separating these streams. Rainfall and mean monthly temperatures were not related to anuran species diversity per month, which may be due to forested sites providing appropriate conditions for reproduction for many species year‐round and favouring anuran species with long breeding periods. The results obtained indicate that streams of varied sizes, as well as streamside habitats, should be preserved in order to maintain anuran diversity.     

Deep-living demersal fishes in the Catalan Sea (western Mediterranean) below a depth of 1000 m

An extensive survey of the deep-living fishes of the Catalan Sea (western Mediterranean) recorded 31 species in 19 families and 29 genera from 100 samples at depths between 960 and 2251 m. Chlorophthalmidae, Moridae and Macrouridae accounted for nearly 85% of all specimens taken. In biomass terms, Hexanchidae, Moridae, Alepocephalidae and Chlorophthalmidae were the most important families. A quantitative model of the bathymetric distribution of the species is presented. The ‘centre of gravity’ of species’ distribution and the habitat width, a measure of the distribution heterogeneity, are also given. Out of the 31 demersal species caught, the distributions of only 13 are centered below 1000 m. The Mediterranean deep-sea ichthyofauna is very impoverished in comparison with the adjacent Atlantic Basin fauna.     

Is the occluded corolla of Antirrhinum bee-specialized?

This paper provides the first results of pollinator fauna associated to the reproductive biology of Antirrhinum charidemi, Antirrhinum graniticum and Antirrhinum braun-blanquetii. Censuses of over 16 hours spanning the flowering phenology of each species were drawn up. As previously hypothesized, the characteristic occluded (personate) corolla of Antirrhinum was exclusively pollinated by bees, but by a higher number (four) of bee families than predicted. Seven bee species (Bombus hortorum, Anthidium manicatum, Chalicodoma lefebvrei, Anthidium sticticum, Anthophora dispar, Xylocopa violacea and Anthidium cingulatum) account for over 90% of flower visits (2098). The flower visitation index varied between species (0.0126?0.0320), reaching relatively medium values compared to Mediterranean plants. In contrast, reproductive success was found to be high when estimated as both fruit (45.4–84.2%) and seed (75.4–98.4%) sets, suggesting that these bee guilds are effective pollinators of the three self-incompatible Antirrhinum species. Specialization of the personate flower of Antirrhinum is therefore interpreted for bees with both large bodies and high visitation indices.     

Marine biodiversity on the Algerian Continental Shelf (Mediterranean Sea)

The Mediterranean Sea is known as a biodiversity hot spot, with 16,848 species reported. Biodiversity is higher in coastal areas and decreases with depth. However, knowledge about the southwestern sector remains scarce. For the last three decades, sampling of soft-bottom communities along the 1180 km of the shallow Algerian coast (0–136 m) has recorded 1642 macrobenthic species. There is a decreasing west–east species-richness gradient, especially for the total species richness and the amphipods. In addition, quantitative sampling in Bou Ismail Bay in summer 1988 (98 sampling sites for a total of 841 species) shows that diversity indices (i.e. species richness, >100 species for 0.2 m^?2; Shannon diversity, >6.0; and ES₅₀, >34) are among the highest for similar sand and muddy-fine sand communities in the Mediterranean Sea and the northeastern Atlantic Ocean. Bou Ismail Bay appears to have the highest species richness among Algerian bays, probably because of its variety of benthic habitats and the absence of significant pollution in this area. Monitoring must be undertaken to survey this high biodiversity, and a national strategy should be proposed to preserve high diversity zones.     

Changes in the littoral macroinvertebrate assemblages of Oak Mere from 1980 to 1998

Data on the macroinvertebrate assemblages of Oak Mere, England are presented for the period 1980 to 1998. There was a marked fall in species richness and numbers of individuals associated with a fall in surface level. Correlations between surface level, areas of vegetation and aspects of the macroinvertebrate assemblages are demonstrated.     

Feeding behaviour of fifteen species of hermit crabs (Crustacea: Decapoda: Anomura) from the Otago region,southeastern New Zealand

Summary

The feeding behaviour of 15 species of hermit crabs from four families (Pylochelidae, Diogenidae, Paguridae and Parapaguridae) and from habitats ranging from rocky intertidal through continental shelf gravelly sediments to finer sediments on the shelf edge and continental slope, is described.

Feeding mechanisms found include various methods of deposit-feeding, browsing, suspension-feeding, predation and scavenging. Each species employs one or two primary feeding mechanisms but also a number of secondary mechanisms. Depositfeeding techniques include scooping up detritus-rich sediment, scrubbing detritus from the surface of small granules, scraping it from larger surfaces, picking it out of crevices and other irregularities, and brushing out and ingesting material which adheres to the general body setation. A few species browse on algae and sedentary colonial invertebrates which they slice or pluck off with the chelae. A number of species filter particles out of suspension using either the general setation of the body and/or specially modified appendages which are swept through the water. Predators either capture and ingest small organisms they encounter more or less accidentally, or actively search for prey. The latter include two species which excavate pits in the sediment in search of burrowing invertebrates. All the species studied fed upon carrion although some fed much less readily than others.

Feeding behaviour in the species studied is discussed in relation to their morphology and habitat. Previously published work on feeding in hermit crabs is reviewed. It is concluded that the broad range of feeding techniques shown by most species is probably of adaptive significance as it enables the crabs to deal with a variety of different foods and substratum types.     

Deep-water amphipods from the Catalan Sea slope (western Mediterranean): Bathymetric distribution,assemblage composition and biological characteristics

Deep-water epibenthic/suprabenthic species of Amphipoda were studied in the Catalan Sea (north-western Mediterranean) at depths from 389 to 1859 m. In four cruises 20 samples were effected during 1991–1992, covering four different seasonal periods (March, April, July and December). A minimum total of 82 species was collected. Ampelisca uncinata and Eusirus leptocarpus were newly recorded as components of the Mediterranean fauna while three other species collected (Bathymedon sp. A, Autonoe sp. and Rhachotropis cf. gracilis) had distinct possibilities to be new species. The Gammaridae Carangoliopsis spinulosa and the Oedicerotidae Synchelidium maculatum were the two main dominant species on the upper slope level (389-506 m). On the middle slope (between 549-601 m), dominance by any few species was not apparent; the Eusiridae Rhachotropis glabra and R. caeca together with Bathymedon acutifrons, Scopelocheirus hopei and Andaniexis mimonectes were the most abundant species. On the lower slope, at depth below 1000 m, R. caeca was the largely dominant species. The highest species richness (S_T) was reported at intermediate depths over the middle slope (63 species), decreasing with depth increase, and being particularly low at 1808–1859 m (19 species). Total amphipod densities were also higher at the upper and middle slope levels (1760.2–2613.9 amphipods/1000 m³) than below 1000 m (376.4–679.2 amphipods/1000 m³). The low swimming coefficients (K_t) of bathyal Gammaridea, ranging between 0 and 0.336, indicate their relationship to the water-sediment interface although interespecific differences in K_t in relation to species size were also reported. Almost all the dominant amphipods had recruits (=smallest juveniles) in two or three of the three seasons sampled (mainly in March and December), and the smallest juveniles were often only abundant in two of these seasons. This indicates that most species had more than one generation per year, probably suggesting bivoltinism, a commonly adopted biological strategy among intertidal, littoral and shallow water amphipods, as the commonest strategy adopted by the mid-bathyal amphipods in our study.     

Composition of meiobenthonic Platyhelminthes from brackish environments of the Galician and Cantabrian coasts of Spain with the description of a new species of Djeziraia (Polycystididae,Kalyptorhynchia)

From 1997 to 1999, the fauna of free‐living Platyhelminthes of the rias ecosystem was studied along the Galician and Cantabrian coast in northern Spain. In total, 72 platyhelminth species are listed in this study. Forty‐two species represent new records for the Iberian Peninsula, three of which represent new genera records. A new species belonging to the genus Djeziraia (Polycystididae, Kalyptorhynchia), Djeziraia longistyla sp. nov., is described in this paper. In this broad‐scale study, a large data set (27 localities) of the estuaries of northern Spain allowed an analysis of the turbellarian species assemblages and the relation of species distributions to salinity, conductivity, oxygen, temperature, and sediment characteristics. Species assemblages (species diversity) of each habitat of the brackish water ecotone are shown. The present study contributes to knowledge on the ability of adaptation of free‐living Platyhelminthes to regimes of brackish water ecotones.