This study presents the first Korean records of two subtropical fish species, Pseudojuloides paradiseus and Diplogrammus xenicus, collected around Jeju-do Island, as well as one boreal fish species, Erilepis zonifer, collected in Busan (approximately 200 km away from Jeju-do Island). In this study, we discuss the implications of the species’ habitat range expansion. Previously, P. paradiseus was known as an endemic species of Japan, while D. xenicus was known to inhabit the Eastern Indian Ocean and the Pacific Ocean excluding around the equator, and E. zonifer was only known to inhabit the Pacific Ocean between eastern Japan and the western USA. Their habitat range expansions might be attributed to the expansion of the Tsushima Warm Current at the surface layer and/or the North Korean Cold Current at the bottom layer. Our findings may suggest that habitat of marine fish is being changed continuously by climate change or oceanic currents. Therefore, it needs to conduct integrated and systematic monitoring of fish fauna to response changing marine biodiversity.

Diapterus brevirostris (Sauvage, 1879) is a fish of the family Gerreidae, native to the tropical and subtropical waters of the Pacific coast of America. A specimen of this species was captured off the coast of Asturias, Spain. To the best of our knowledge, this is the first record of the genus Diapterus in the North Atlantic. Given its small size (6.4 cm), it is likely that the species was present in the area for a relatively short time. Although the introduction pathway is unknown, the species' native area and the proximity of a major port to the site of capture suggest that ship's ballast water is the most likely vector of introduction.

Here, we report the first validated record of the non-indigenous grouper species Epinephelus areolatus (Perciformes: Serranidae) along the Mediterranean coast of Syria. A single specimen of E. areolatus (Forsskål, 1775), was found on 29 September 2021 during a recurrent ichthyological survey, in a rocky habitat from the Mediterranean coast of Syria. This represents the first confirmed record of this species, native to the Red Sea, for the Syrian waters and the fourth for the Mediterranean Sea. The present record fills the gap with species distribution along the eastern Mediterranean and provides further evidence that the environmental alterations due to the combination of human activities and climate change render the Mediterranean waters increasingly likely to accommodate tropical species, possibly at the expense of the native ones.

The smallest fish of the Mediterranean Sea, pygmaean goby, Pomatoschistus nanus, and Massuti's goby, Buenia massutii, were obtained from new locations. While P. nanus specimens were collected from both the north-eastern and south-eastern Aegean Sea, B. massutii specimens were collected from two different sub-basins, Sea of Marmara and the Aegean Sea, representing the first report of this species in the eastern Mediterranean Sea. The species were identified by both morphological and molecular techniques. The present paper contributes to filling gaps in the knowledge of the limited distribution of these species in the eastern Mediterranean Sea.

Okenia aspersa is a north-eastern Atlantic species, only previously recorded as Okenia quadricornis from the Malta Archipelago in the Mediterranean Sea, and in juvenile forms, from Sicily and the Gulf of Naples. A second adult specimen is recorded in the present paper, which was found along the Noli Cape coast, in the western Ligurian Sea (Italy). It was found on pebbles at a depth of 10 m. In the same area, at a depth of 5.5 m, two specimens of Doto koenneckeri and three of their egg masses were found. This species, also described from Norway and Ireland, was only previously known to occur in the Mediterranean Sea off Spain and France. It is likely that the cold winter temperatures of the Ligurian Sea allowed this species to live and reproduce.

A red algal species, Polyneura bonnemaisonii (Delesseriaceae, Rhodophyta), is described for the first time in the Atlantic Ocean of Morocco. This is also the first reference of the occurrence of this species in Africa. This species was collected in the lower intertidal to subtidal zones, from Hyayda (north-west of Morocco). The Moroccan specimen is studied in detail and compared with other closely related species. Habitat, geographic distribution, description and illustration of the macroscopic and microscopic characters are presented and discussed in this work.

The occurrence of Cavernularia pusilla is reported for the first time from the Sea of Marmara, extending the range of the species in the eastern Mediterranean and providing the first report of the species from Turkish waters.

The northernmost record of the alien nudibranch Godiva quadricolor is reported here, about 400 km farther north than the previously published one and the farthest to be recorded from the equator. It is also the second published record of this species along the Italian coasts and the first record from the Ligurian Sea. A single specimen was reported during a scuba dive, crawling on small stones inside the Site of Community Importance ‘Fondali Noli – Bergeggi SCI’, at a depth of 3.5 m. The species, described in 1927 in South Africa, is considered to be rapidly expanding its original areal distribution thanks to maritime traffic. A review of the known actual distribution is also reported here.

The first record of Lebetus guilleti for the Italian seas is reported here. The finding is based on photographic records of specimens located in shallow waters off the Conero Promontory (An) along the Adriatic coast of Italy. This record expands the distribution range of this species in the Mediterranean and moves its southern limit in the Adriatic Sea 170 km further south, adding to the suspicion that the distribution of this cryptic species might be wider than previously described. Recreational SCUBA diving focused on biodiversity observations and underwater photography proved instrumental again in providing information about the presence and distribution of marine fauna, including the most easily overlooked species.

This paper reports seven species of opisthobranchs from the intertidal zone of the south Saurashtra coastline off the Arabian Sea, Kathiawar Peninsula, west coast of India. Field surveys were undertaken along the intertidal zones of south Saurashtra coast during 2012–2014. In this study, seven species belonging to six families were recorded, of which Haminoea ovalis, Flabellina bicolor, Phidiana militaris, Baeolidia palythoae and Sakuraeolis gujaratica are new records from this coastline.

The cookiecutter shark, Isistius brasiliensis, is confirmed for the first time from the eastern North Pacific Ocean. The shark, a female 432 mm in total length, was caught in a sablefish pot at a depth of 1132 m off San Nicolas Island, California, USA (32°59′05″N 120°25′99″W).

Even though very few biological data on dinoflagellates from Iraqi aquatic ecosystems are available to date, there are none on the genus Scrippsiella. For this reason, the survey was conducted along four sites in the Shatt Al-Arab River between November 2009 and July 2010. A dense population of Scrippsiella-like dinoflagellate was observed in the studied samples during November and December 2009. Less dense population of the same taxon was encountered in the downstream sites in July 2010. Based on observations of thecal plate pattern in epifluorescence microscopy, the species was attributed to Scrippsiella trochoidea. The occurrence of S. trochoidea is reported for the first time in Iraqi waters from a wide range of temperature (17.9°C–35.2°C) and salinity (2.3–16.7).

The stalked barnacle Dosima fascicularis is reported from Uruguayan waters for the first time based on stranded specimens. It is suggested that the Subtropical Front is the main area of occurrence of D. fascicularis in the South Atlantic and its occurrence on the Uruguayan coast was found to be sporadic and mainly related to singular atmospheric and oceanographic factors that cast ‘blue plankton’ ashore (e.g. easterly and south-easterly winds, and prevalence of tropical waters).

This is the first record of the black scorpionfish Scorpaena porcus being found in the eastern English Channel. A specimen was caught on 15 October 2012 off the port of Courseulles-sur-mer. It measured 31.6 cm and weighted 800 g. From a study of its sagittal otolith, this specimen appeared to be 9 years old.

The Red pandora Pagellus bellottii was recorded for the first time in the south-eastern Mediterranean in Haifa Bay, Israel, on 20 January 2010. Apparently, this eastern Atlantic Ocean species has recently started to disperse into the eastern Mediterranean. After an initial record from Syria in 1992, this is the second record from the eastern Mediterranean, which indicates the possibility that small populations may have established themselves there.

Five living specimens of the Aglajidae Spinoaglaja wildpretii are reported from north-eastern Sardinia (Tyrrhenian Sea); these are the first records from Italian shores, the first record of living specimens in the entire Mediterranean and they noticeably enlarge the known range of the species. Some ecological notes are added.

The African brown snapper Lutjanus dentatus is a fish native of the West African coastal zone of the Atlantic Ocean. Here we document the first recorded capture of this species in the Canary Islands, an archipelago close to Africa, in August 2013.

Two specimens of Stegastes fasciolatus of total length 110.1 mm and 112.2 mm were collected from gillnet at Visakhapatnam fishing harbour, north-east coast of India on 5 January 2013. The morphometric and meristic characters of the recorded specimens are described and discussed.

This is the first record of Grammonus robustus from Indian waters. Five specimens measuring 132–233 mm standard length were collected from the by-catch landed by a deep sea trawler from waters 150 to 200 m deep off the Tuticorin coast in the Gulf of Mannar. The detailed morphometric and meristic characters are compared to known G. robustus material.

The capture of one specimen of Chilomycterus spinosus mauretanicus from the Andalusian coast (Alboran Sea, western Mediterranean) represents the first record in Mediterranean waters.