The surroundings of the rocky island of Helgoland (German Bight, south-western North Sea) are one of the best-studied sites in European seas with species occurrence data available for nearly 150 years. As the area is strongly affected by global change (e.g. increase in mean sea surface temperature at Helgoland by 1.67°C since 1962), ecosystem structure and function are expected to change more than those of average marine systems. The paper presents a supplement to the local amphipod species inventory (5 nautical miles around the island). At least seven species of this ecologically important taxon seem to have newly established themselves at Helgoland since the late 1980s: Ampelisca typica, Amphilochus brunneus, Caprella mutica, Cheirocratus assimilis, Monocorophium acherusicum, Orchestia mediterranea and Orchomenella crenata. Most of them are not only new for the Helgoland area, but also for the German Bight; and two species (Amphilochus brunneus and Orchomenella crenata) are even new to the North Sea as a whole. Out of the seven new species, one (Caprella mutica) is a neozoon from the north-western Pacific. The other six species show clear warm water affinities (oceanic–Lusitanian species) which suggest a recent range expansion in the context of climate warming. The establishment of an increasing number of species formerly probably absent from the area does not seem to be compensated by losses of species, so that local species diversity is expected to increase.

A total of 168.4 hours of visual cetacean survey work was carried out in association with two geophysical surveys in Montserrat waters (eastern Caribbean) during December 2007 and May 2010, using a seismic vessel as a platform of opportunity. Nine cetacean sightings were recorded: pantropical spotted dolphin Stenella attenuata (N = 2), Fraser's dolphin Lagenodelphis hosei (N = 1), sperm whale Physeter macrocephalus (N = 1), humpback whale Megaptera novaeangliae (N = 1), and sightings of unidentified dolphins (N = 1) and large whales (N = 3). A total of 73.3 hours of acoustic monitoring effort was carried out during December 2007, resulting in 19 cetacean detections. Sperm whale (N = 10) and unidentified dolphin (N = 7) detections predominated. Two acoustic detections were of pantropical spotted dolphins, corresponding with visual sightings. An opportunistic sighting of 14 pygmy killer whales Feresa attenuata during October 2008 was reported. Although the humpback whale was known previously for Montserrat waters, the sightings of other species represent the first verified records for the state.

The population structure and biological aspects of the shallow water mysid Mesopodopsis orientalis were studied in the Versova mangrove, Mumbai, India. The monthly collections ranged from 0–2104 ind.m−3with an average of 78.6 ind.m−3. The sampled population was found in a wide range of temperature (25.5°C to 34°C) and salinities (20.3 to 37.1). Carapace length significantly correlated with total body length (P < 0.01). Mesopodopsis orientalis breed throughout the year but there is a seasonal variation in the intensity of breeding. The size of mature males and females was at maximum during the post-monsoon period. The species produced more than one generation per year and the number of embryos carried by a single female ranged from 6–18, and was correlated with female body length (R2 = 0.69). Egg size varied between 0.32 and 0.45 mm, with no correlation with length of females.

Length–weight relationships of four pipefish and two seahorse species from Tunisian waters are presented in this paper: the straight-nosed pipefish Nerophis ophidion, the black-striped piperfish Syngnathus abaster, the greater pipefish S. acus, the deep-snouted piperfish S. typhle, the short snouted seahorse Hippocampus hippocampus and the long-snouted seahorse Hippocampus. ramulosus. Overall, 2424 specimens of these six syngnathid species were weighed and measured. The sample size ranged from 14 for N. ophidion to 1773 for H. ramulosus. The values of the slope b in the length–weight relationships (W = aLb) varied between 1.836 (S. typhle) and 5.476 (N. ophidion). Linear regressions of length–weight relationships were significant for all species. We have calculated a positive allometry in weight versus length for N. ophidion, an isometry for H. hippocampus and H. ramulosus and a negative allometry for S. abaster, S. acus and S. typhle.

The mysid Hemimysis lamornae mediterranea Bacescu, 1936 is described from specimens sampled in the Ebro Delta, Spain, north-western Mediterranean. To date, this subspecies was only known from the Gulf of Naples and Marseille; this is the first record of the H. lamornae mediterranea on the Iberian Peninsula coast. Hemimysis lamornae mediterranea is distinguishable from its closest congeners, H. lamornae typica (Couch, 1856) and H. lamornae pontica (Czerniavsky, 1882) by the number of setae, the shape of the maxilla, and the relatively smaller number of spines on the uropod endopod and on the lateral margin of the telson.

The ringed basket star Astrodictyum panamense is an ophiuroid resident of coral and rocky reefs from the central and southern Gulf of California and oceanic islands from the eastern Pacific. This paper presents new records of this species obtained from fieldwork and internet sources, and includes its northernmost and westernmost occurrence in the eastern Pacific (Adair Bay, Gulf of California, and Tortugas Bay, on the Pacific side of Baja California, respectively), as well as Roca Partida Island, in the Revillagigedo Archipelago.

In the past half century, a number of studies have described the general composition of the mesozooplankton of Southampton Water, but little attention has been paid to the occurrence of parasitic and commensal species. In order to fill this gap, the occurrence and distribution of parasitic/commensal species was investigated in three fixed stations along the estuary in 2001/2002. A total of 16 parasitic taxa were identified, including 11 new records for the zooplankton of Southampton Water. The most frequent and abundant parasitic taxa observed in the estuary were Peltogaster paguri, Sacculina carcini, Siphonostomatoida copepodites and cryptonistic forms of isopods. This study is the first report on ‘free-forms’ of parasitic/commensal species within the mesozooplankton of Southampton Water being also a reasonable indicator of the presence of the infected/associate host in the estuary or surrounding areas.

The present study reports new records of the invasive pygmy mussel Xenostrobus securis in six brackish-water localities in the western Mediterranean. Until now X. securis, whose native range includes southern Australia and New Zealand, was also known from the northern Adriatic Sea and southern France. Along the coast of northern Tuscany (Italy) X. securis invaded brackish-water canals in the area between the port of Leghorn and the mouth of the Arno River. Moreover, this mussel has been found in one inner site of the Gulf of Olbia (north-eastern Sardinia, Italy) and at the mouth of the Fluvià River (northern Catalonia, Spain). As an ecosystem engineer, X. securis is an ecologically important species, heavily altering pre-existing benthic communities. Given that its presence in other western Mediterranean sites is highly possible, we recommend a closer monitoring of brackish-water biotopes.

The occurrence of the merluccid Macruronus novaezelandiae from tropical waters off Bahia, eastern Brazil, is reported for the first time due to the capture of an adult of 712.3 mm standard length in May 2008, from a depth of 400 m. Until then no specimen had been reported north of 32°29′S on the South American Atlantic coast. This new record extends the species' range to about 2500 km northwards along the Brazilian coastline and is the first ever from tropical waters in the world. A comparison of the morphometric characters is provided.

Four specimens of the clingfish Tomicodon zebra were caught on the intertidal zone El Pital, El Salvador, Central America. This record extends its known range two latitudinal degrees southward in the Tropical Eastern Pacific.

Here we report the second and third known specimens of Cephalopholis fulva with partial melanic coloration, photographed at Fernando de Noronha Archipelago and Camamu Bay, south-western Atlantic. While the species exhibits a wide range of colorations, the melanic pattern is an aberration only recently reported. Since C. fulva is common within its area of distribution and is of importance to fisheries, increasing records of melanism can either result from higher frequency than previously thought or, alternatively, that this condition is becoming more common.

The capture of the species Bythocaris cosmetops in the Alboran Sea (southern Spain, western Mediterranean Sea), previously known from only two specimens from the Atlantic, Sierra Leone (south-west Africa) and the northern Bay of Biscay (north-west Europe), represents the first record of the genus and species in the Mediterranean Sea and Iberian Peninsula (south-west Europe). New data on morphology, biology and habitat are provided and discussed.

Habitat use of Manta alfredi and M. birostris was assessed at 20 localities in the Indian and Pacific Oceans based upon 3328 photographic observations. Geographical relationships of the two species were scored as either microallopatry, microparapatry or microsympatry at each locality. Our study revealed a mosaic habitat occupancy by the two species within their macrosympatric range.

A male specimen of Tripedalia cystophora (Cubozoa: Tripedaliidae) was collected from Lake Wyman, Boca Raton, Florida, USA. This is the first report of this species from the continental United States and brings the total known number of cubozoan species living in this region to four. Lake Wyman is a natural lagoon/estuary ecosystem which is part of the Atlantic Intracoastal Waterway. The box jellyfish was found in shallow water around the roots of the red mangrove, Rhizophora mangle, where it was observed feeding on copepods attracted to light. This finding may indicate a local population in the waters of south Florida, USA, but an isolated occurrence cannot be ruled out.

The rare ophichthid eel Asarcenchelys longimanus is reported for the first time from Bahia State, north-eastern Brazil. To date, only two specimens of A. longimanus, the holotype and a paratype, were known. The new finding extends its distribution to about 2400 km southwards along the Brazilian coastline and provides a new maximum size for the species. Comparisons of the morphometric and meristic data between our specimens and those used in the original description are provided.

Here we report on intraspecific cleaning behaviour between two adult bluestreak cleaner wrasse Labroides dimidiatus of similar size on coral reefs surrounding Lizard Island, Great Barrier Reef, Australia. During a SCUBA dive, we observed these individuals posing and the resulting cleaning interactions. While aggression in this species is common between adults of similar size and social class, our observation suggests that these individuals may also cooperate and partially rely on conspecific individuals for cleaning.

Syngnathus rostellatus is a nearshore pipefish species whose distributional range extends along the European Atlantic coast between Bergen (NO) and the Bay of Biscay (ES). Several recent articles suggest that this species has experienced a major range expansion of more than 4000 km into the eastern Mediterranean, but a critical review of these studies indicates that the majority of these reports are based on specimen misidentifications. Considering a reliable report of S. rostellatus from the Mediterranean coast near Gibraltar, it appears that the current distribution of this species is restricted to the north-eastern Atlantic Ocean and the southern Mediterranean coast of the Iberian Peninsula.

In August 2009 six specimens of the ovulid gastropod Xandarovula patula (Pennant, 1777) (formerly known as Simnia patula Pennant, 1777), were found in dredge samples from a locality west of Smögen in western Sweden (58°22′N 11°05′E). In June and November 2010 a total of three specimens of the same species were found in dredge samples from near Svelgen Bridge, Øygarden, Hordaland, western Norway (60°27 ′N 04°57 ′E). Several small colonies of the presumed prey species, Alcyonium digitatum Linnaeus, 1758 and Tubularia indivisa Linnaeus, 1758, were found in the same dredge hauls. Xandarovula patula has been recorded from the Atlantic coast of southern Spain to the western end of the English Channel, with scattered records from the west coasts of Ireland and Britain, as far north as the Orkneys. More recently it has been reported from most Irish coasts, several parts of the Scottish coast and also from some places in the North Sea. Until now there have been no confirmed records from Scandinavian waters. The specimens recorded here may indicate recent immigration of a southern species due to warmer water temperatures.

Two jellynose fish captured in southern Brazilian waters were identified and compared with the previous descriptions of ateleopodid species to improve our understanding of the diversity and distribution of these fish off Brazil. The body of each individual is elongate, tapering, and posteriorly compressed, with a large, robust head with relatively small eyes (~7% head length), a short trunk and a long tail. Radiographs of the specimens show two undeveloped pelvic rays buried in integument and five caudal rays originating from the last vertebrae which are exclusive characteristics of Ijimaia antillarum.

The pan-tropical spotted dolphin Stenella attenuata is typically found in deep tropical and warm temperate waters and has been previously confirmed from the waters of most of Pakistan's neighbouring countries. However, to date, there has been no record of this species from Pakistan. This paper reports the first confirmed occurrence of this species in Pakistani waters, specifically a mass stranding event of 200–250 animals on 6 March 2009. The animals live stranded and all except two were rescued. These possibly died as a result of being stranded for a long time on the beach in hot, arid conditions that generally prevail along the coastline of Pakistan. All the animals appeared healthy but the exact cause of this mass stranding event could not be determined. Being the first confirmed record of this species in Pakistan, this information is an important addition and consideration for the Pakistan Biodiversity Action Plan.