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The short-beaked common dolphin (Delphinus delphis) is regarded as notably rare or absent from the northern North Sea, but recent evidence suggests a rising frequency of the species in these waters with increasing regional sea temperatures. The following paper documents the presence of D. delphis in the Moray Firth in north-east Scotland and provides the first evidence for the sustained occurrence of these delphinids in this region during the warmer summer months at least. Sightings were collated during systematic surveys of the outer Moray Firth between 2001 and 2009 by independent research teams from the CRRU and WDCS. A total of 13 encounters (with group sizes ranging from 2 to 450+ animals) were recorded with the species across this period, the first of which was in June 2006, with annual encounters being logged thereafter between the months of May and August from 2007 to 2009 inclusive. The animals were recorded in water depths of 51 to 209 m (mean depth: 88.6+42.2 m) and at a distance from shore of 5 to 32 km (mean distance: 16.6 ± 8.0 km). New born calves were observed in June and July, and photographic recaptures of identifiable 'marked' adults were determined in 2009. The consistent presence of common dolphins in the outer firth post 2005 and the recapture of recognizable individuals suggest a comparatively recent colonization of these waters by the species over a relatively short period of time. The impacts resulting from such a range expansion upon the existing cetacean community and the subsequent implications for management are discussed. [ABSTRACT FROM AUTHOR]

Port Stephens, on the central New South Wales coast, provides ideal oceanographic and benthic conditions for the settlement and growth of larvae of tropical species delivered from the north by the East Australian Current. The popularity of the bay for recreational and scientific diving has facilitated extensive documentation of the biota over several decades, confirming its high biodiversity. Of the 313 species of heterobranch sea slugs recorded from Port Stephens to date, 30 are not known to occur further south. Our observations increase the number of taxa with a southern distribution limit at Port Stephens by 12 species and add to a growing list of marine taxa that are progressively extending their southern range, potentially as a result of climate change. [ABSTRACT FROM AUTHOR]

On 8 May 2010, a gray whale was sighted off the Israeli Mediterranean shore and twenty-two days later, the same individual was sighted in Spanish Mediterranean waters. Since gray whales were last recorded in the North Atlantic in the 1700s, these sightings prompted much speculation about this whale's population origin. Here, we consider three hypotheses for the origin of this individual: (1) it represents a vagrant individual from the larger extant population of gray whales found in the eastern North Pacific; (2) it represents a vagrant individual from the smaller extant population found in the western North Pacific; or (3) it represents an individual from the previously thought extinct North Atlantic population. We believe that the first is the most likely, based on current population sizes, on known summer distributions, on the extent of cetacean monitoring in the North Atlantic and on the results of a performed route analysis. While it is difficult to draw conclusions from such singular events, the occurrence of this individual in the Mediterranean coincides with a shrinking of Arctic Sea ice due to climate change and suggests that climate change may allow gray whales to re-colonize the North Atlantic as ice and temperature barriers to mixing between northern North Atlantic and North Pacific biomes are reduced. Such mixing, if it were to become widespread, would have implications for many aspects of the marine conservation and ecology of these two regions. [ABSTRACT FROM AUTHOR]

The current amendments to the Mediterranean marine Non-Indigenous Species (NIS) inventory for the period 2017-2019 are the result of a continuous literature search and update of the Hellenic Centre for Marine Research (HCMR) offline database. They take into account recent findings, previously missed records, back-dated records based on the re-examination of existing material or phylogenetic studies and changes in nomenclature. During the period 2017-2019, 70 new species were added to the inventory of established species, 25 that had escaped our attention in the past and 23 newly introduced, which have already established self-sustaining populations. Meanwhile, 22 species previously known only with casual records have established viable populations and a total of 36 species have expanded their distribution into new Marine Strategy Framework Directive regions, primarily the Central Mediterranean and the Adriatic Sea. Intensified research efforts, prompted by the reporting obligations created by recent legislation, complemented by ever expanding networks and initiatives involving citizen scientists have certainly contributed to higher rates of discovery of alien species presences. However, the expansion of tropical and sub-tropical species into the cooler waters of the Aegean, the Adriatic and the western Mediterranean indicates that the warming of Mediterranean waters due to climate change is also facilitating the geographic expansion of NIS in the region. The rate of new introductions in this 3-year period is 8 species per year for the whole Mediterranean, without taking into account casual records or species with reporting lags. Only 4 species per year enter through the Suez Canal, while a considerable number of species are introduced through shipping vectors and the aquarium trade. Acknowledging the dynamic nature of invasions and the uncertainty inherent in compiling check lists, we consider the present work as the most accurate and up-to-date NIS list to inform policy, management and decision-making. [ABSTRACT FROM AUTHOR]

A spinetail devilray (Mobula japanica) was recorded for the first time in the western waters of Australia. The beach-stranded individual was observed in March 2013 on the southern coast of Western Australia (latitude 34.8811°S, longitude 118.4079°E). This is the southernmost record of this species in Australian waters. Previous Australian records of this species have been restricted to the east coast, where sightings have been within the latitudinal range of 14–33°S. The individual observed in Western Australia was a mature male, with a disc width of 257 cm. The occurrence coincided with the maximum recorded summer sea surface temperature (22.0°C) along the southern coast of Western Australia and an abnormally strong flow in the Leeuwin Current for that time of year. [ABSTRACT FROM PUBLISHER]

The decapod Hippolyte prideauxiana is a cryptic commensal of the crinoid Antedon bifida, giving rise to its common name ‘the feather star shrimp’. In 2010 and 2013 H. prideauxiana was recorded in the Shetland Islands and the Orkney Islands (‘north isles’), northern Scotland. These observations widen the known geographical distribution of this species by 400 km north from the west coast of Scotland where it was first recorded in 1997. Whilst it is possible that these new records are the result of a range expansion due to climate change it is more likely that this species has been overlooked due to its cryptic coloration, limited awareness of this species and increase in survey effort in the north of Scotland using SCUBA. [ABSTRACT FROM PUBLISHER]

New distribution records from Britain and Ireland for six species of rare goby from nearshore areas are reported. The value of photographic records obtained by recreational SCUBA divers using digital cameras in underwater housings is demonstrated. The six species included are Buenia jeffreysii, Gobius couchi, Gobius cruentatus, Gobius gasteveni, Lebetus scorpioides and Lebetus guilleti. [ABSTRACT FROM AUTHOR]

The inter-relationship between the pea crab Pinnotheres sinensis and its bivalve host Septifer virgatus was studied from July 2002 to December 2004. The infested bivalve generally contained a single crab (72.4–94.7%), but multiple infestation was also observed in some cases (5.3–27.6%). Seasonal fluctuations in the prevalence rate, sex ratio and ovigerous rate were examined. The prevalence rate and sex ratio increased in autumn and decreased from spring to summer. By contrast, the rate of the ovigerous female increased in summer and decreased in autumn. The carapace width of females was larger than that of males, and seasonal fluctuation in the carapace width was observed in the female crabs. All the females had a soft carapace whereas most males had a hard carapace. No females were observed outside the host, though a small number of males were observed outside it. Mating probably took place inside the host where females remained stationary, with males visiting different bivalves as well as spending much time outside the bivalves. [ABSTRACT FROM PUBLISHER]

The occurrence of the tropical seagrass species Halophila stipulacea (Hydrocharitaceae) is reported within the harbour of Palinuro (Salerno, central Tyrrhenian Sea, Italy). The bottom covered by the seagrass has been evaluated in about 16 m2, fragmented in various small patches distributed in a narrow belt between 0.5 and 5 m depth, and all settled on dead matte of the endemic Mediterranean seagrass Posidonia oceanica. Mean density was 10,500 shoots m−2. This record documents a displacement of about 180 km north of the previously documented limit of Halophila stipulacea in the western Mediterranean, likely mediated by pleasure boat traffic and anchoring, and favoured by climate change. This record illustrates a further example of the changing Mediterranean Sea biogeography: north–south patterns in biotic ranges will probably replace the presently well established west–east patterns in the Mediterranean Sea of tomorrow. [ABSTRACT FROM PUBLISHER]