The Neptune Islands Group and Western Kangaroo Island Marine Parks were declared as part of South Australia’s representative system of Marine protected areas (MPAs) in 2009. Sanctuary zones, located within these MPAs, prohibited commercial fishing in the state’s Northern Zone Rock Lobster Fishery from 2014. In 2022, dedicated surveys were undertaken both inside and outside two of the sanctuary zones to estimate the relative abundance (catch per unit effort; CPUE) and size of southern rock lobster (Jasus edwardsii). Survey results were then compared to estimates of abundance obtained from long-term commercial fishery-dependent data within each area. The legal-size CPUE by weight of lobsters was 389% and 411% higher inside sanctuary zones of the Neptune Islands Group and Western Kangaroo Island, respectively, compared to outside, based on survey data. Survey catch rates inside the two sanctuary zones were also considerably higher than historical catch rates estimated from commercial fishing data. Lobsters inside both sanctuary zones were larger than those outside in terms of mean weight compared to historical estimates. However, surveys recorded similar mean size in lobsters both inside and outside the Neptune Islands Group sanctuary zone, indicating a possible spillover effect of MPA protection. The Northern Zone Rock Lobster Fishery is currently in a biomass rebuilding phase. The results highlight the productivity potential of temperate reef ecosystems within South Australia in terms of southern rock lobster abundances.

Hydrothermal vents are known to host unique faunal assemblages supported by chemosynthetic production; however, the fauna associated with inactive sulphide ecosystems remain largely uncharacterised across the global seafloor. In November 2023, a six-rayed starfish was collected from the Semenov hydrothermal field on the Mid-Atlantic Ridge. A combination of morphological and molecular methods has confirmed the identity of this species as Paulasterias mcclaini Mah et al. 2015 (Forcipulatida: Paulasteriidae), providing the first validated record of this family in the Atlantic Ocean. We present an updated morphological description of the species, alongside phylogenetic analysis of the COI, 16S, 12S, and H3 genetic markers. The biogeography of the family is discussed, and previously published records amended.

Bowmouth guitarfish (Rhina ancylostoma) is typically described in the literature as a coastal ray species that inhabits nearshore waters up to 70 m deep on the continental shelf, dwelling on or near the seafloor, primarily over sandy or muddy substrates and around coral reefs. However, the scientific monitoring programme aboard the Spanish and Seychellois tropical tuna purse seine fleets has documented 37 incidental captures of this species in open waters of the Indian Ocean, through onboard observers and electronic monitoring systems. All these captures occurred within the first 200 m of the water column, at locations where the maximum depth exceeded 2000 m. The study was conducted based on at-sea observations onboard the Spanish and Seychellois tropical tuna purse seine fleets operating in the Indian Ocean from 2017 to 2023. The observation coverage varied throughout this time-series, with more than 85% of fishing activity monitored since 2017. The interactions recorded were predominantly between January and May, and more frequent in the years 2018 and 2021. The captured individuals ranged from 150 to 250 cm in total length, with females recorded more frequently than males. These observations provide valuable insights into the large-scale movements of this neritic species beyond its typical coastal and inshore habitats in the Indian Ocean.

A new species of the genus Verdeia is described from the continental slope of the Potiguar Basin, Rio Grande do Norte, Brazil at a depth of 150 m. Verdeia setosa sp. nov. is readily distinguished from its congeners by the ornamentation of the larger gnathopod 2 in males and the densely setose basis of pereopods 6–7. This is also a new record of the genus from Brazilian waters. We presented an amended diagnosis of the genus to accommodate all Verdeia species and discuss these changes. Furthermore, an identification key to the family Melitidae from Brazil is provided.

The current study records a new distributional range for Elysia cf. leucolegnote Jensen, 1990, which was previously reported only from the Andaman and Nicobar Islands in India. The collection was carried out in the mangroves of Kali Estuary situated in Karnataka (14°50ʹ55.27″N, 74° 9ʹ44.04″E & 14°50ʹ16.36″N, 74°10ʹ8.81″E), southwest coast of India. Prior studies had documented the distribution of this species in the tropical West Pacific and East Indian Oceans; this study reports the first record of E. cf. leucolegnote in the Northwestern Indian Ocean, expanding its documentation of a wider distribution range. The species was first discovered in Hong Kong and described in 1990. It was identified by its distinctive morphological characteristics, which featured black eyes situated proximally at the base of the rhinophores and a flattened, generally green body with a distinct white border line along the rhinophores and parapodia.

Chiroteuthis picteti (Joubin, 1894) is an oceanic squid previously documented from both the Pacific and Atlantic oceans. This is the first report of C. picteti from Andaman Sea. Three specimens were collected from seashore of Corbyn’s Cove, Port Blair, Andaman and Nicobar Islands. All three specimens were identified using morphological characteristics and the COI gene was used for molecular identification. Both morphological and molecular analysis confirmed this species. Our study also suggests the possibility of genetic differentiation within this species since the phylogenetic analysis showed two well-supported clades within C. picteti. One clade consists of sequences from the Indian Ocean (sequences generated in this study), while the other includes sequence from the Pacific Ocean. Further studies are needed to confirm the presence of cryptic groups within this species.

Medusozoa comprise a diverse group of marine invertebrates that includes cubozoans, hydrozoans, staurozoans, and scyphozoans, which play a fundamental role in marine ecosystems. In Cuba, with exceptions, most of the studies of the phylum Cnidaria have focused on the scleractinian corals. However, their close relatives, the jellyfish have been poorly addressed, limiting themselves to isolated records of some species. In this study, we aimed to update the list of medusozoan species registered in Cuba and compare it with the registries in the Greater Caribbean region. Peer-reviewed publications, museum collections, field-trips, global repositories, and social networks were accomplished to compile a species list. Twenty-one new species are recorded, and the distribution of 11 species previously reported is expanded. Cuba, with 361 species is the country with the highest species richness in the Caribbean region: 342 species of Hydrozoa are distributed in 69 families, 16 species of Scyphozoa are distributed in 10 families, and three species of Cubozoa each belong to one family. Analysing the studies of Medusozoa reveals significant heterogeneity in jellyfish species composition across the Caribbean region, where Cuba, Puerto Rico, Mexico, and the USA are the countries with the highest species richness. A high similarity was observed between the assemblages from Cuba and the USA. The number of jellyfish species reported for Cuba constitutes a baseline for ecological studies of their integrated role in marine ecosystems. Studies in the Caribbean region are heterogeneous, with an imbalance in the sampling effort in time and space and probably underestimate the number of species known.

This study investigates the accumulation of glycogen, amino acids, and fatty acids in male Mytilus coruscus during different stages of gonadal development and explores their relationships with reproductive processes. Glycogen levels were highest during the resting phase, decreasing progressively during the proliferation and maturation phases. A positive correlation was observed between glycogen and carbon content, indicating a close association between energy storage and metabolic processes. Amino acid content, particularly essential amino acids (EAAs), increased during gonadal development, reflecting the higher demand for protein synthesis and cellular metabolism. Branched-chain amino acids (BCAAs) such as isoleucine, leucine, and lysine were key in activating protein synthesis and supporting gametogenesis. Non-essential amino acids like aspartic acid, glutamic acid, and glycine also accumulate, supporting cellular function and reproductive regulation. Fatty acids, especially unsaturated fatty acids (UFAs) and polyunsaturated fatty acids (PUFAs), progressively accumulated in the testes, highlighting their role in energy supply and membrane integrity during gametogenesis. Phosphorus (P) accumulated in parallel with fatty acids, supporting DNA and RNA synthesis, energy metabolism, and cell membrane function. This study emphasizes the crucial role of these biochemical components in supporting gonadal development in male M. coruscus, providing insights into the metabolic pathways involved in marine bivalve reproduction.

San Sebastián Bay, in southern South America, is an emblematic area because it represents a conflict of interest between the conservation of migratory birds and marine species and the exploitation of hydrocarbons. Given the little information available about the intertidal benthic communities in this bay, this study aims to analyse shell assemblages recovered from the beach, examining drilling and crushing predation on mollusc shells. Two bivalves, Darina solenoides and Mactra fuegiensis, are being preyed upon by three potential drilling predators: the naticid Falsilunatia limbata and the muricids Xymenopsis muriciformis and Trophon geversianus. The intensity of drilling predation was high in both bivalve prey, being higher in M. fuegiensis (27.4%) than in D. solenoides (18.8%). Additionally, there was no preference observed for a particular prey size and there was also no significant correlation between the size of the prey and the predator. However, site selectivity indicated that the predator showed a preference for the central sector in D. solenoides and the umbonal sector in M. fuegiensis, that could be explained by the life modes of both prey and how they are manipulated by their predators. Finally, regarding crushing predation, the shell condition of a significant number of muricids indicates damage most probably caused by decapod crabs. This work provides valuable insights into the biotic interactions within the intertidal communities of San Sebastián Bay, located in the cold-temperate Magellanic Region. It highlights the necessity for continued research and monitoring, particularly in an already conflictive context aggravated by climate change.

Gammaridean amphipods are a major component of macrobenthic communities, but information on their distribution and ecology in subtidal habitats of northern Japan is limited. We present the species composition and community structure of benthic amphipods in the subtidal bottoms (5–32 m deep) of Akkeshi Bay, eastern Hokkaido, Japan, and examine whether spatial variability of amphipod assemblage is related to local environmental gradients and biogeographic affinities of the component species. Amphipods were collected at nine sites in 2020 and identified to 40 species consisting of 21 families. Similarity analyses showed that the amphipod community differed among the three habitats: (1) marine soft-bottom substrate, (2) gravelly estuarine substrate, and (3) marine hard-bottom substrate. Distance-based redundancy analysis revealed that variation in the soft-bottom community was related to that of depth and sediment composition. The biogeographic affinities of 15 identified species were categorized as two groups, “Arctic and surroundings” and “Northwestern Pacific,” by similarity analysis with global occurrence records in marine ecoregions. Differences in species composition were related to the biogeographic affinities of the component species, with species grouped as Arctic and surroundings occurring at deeper sites than the Northwestern Pacific species. Changes in community structure along the depth gradient reflected variations in environmental factors, such as temperature, as well as differences in the suitable temperature ranges of the species as determined by their biogeographic history. This study highlights the importance of considering both environmental gradients and macroecological features of component species in interpreting variations in amphipod community structure on the local scale.

Microplastics are found in all oceanic environments and represent a growing concern for researchers and managers of marine environments. A systematic review was carried out to investigate the accumulation of microplastics (MPs) in filter feeders, focusing on the potential relationship between the feeding mechanism and MPs’ accumulation. The accumulation of microplastics was compared among marine benthic filter feeders that use different filtering mechanisms. Rayyan® software was employed to screen the articles, and data extraction was subsequently carried out. The review followed well-structured protocol PRISMA 2020 guidelines to guarantee methodological rigor and minimize biases. Due to the high heterogeneity (Higgins I2 test, I2 > 95%) of data methodologies, a narrative synthesis was used as the output of the review. Most publications report microplastics in mollusks (oysters, mussels, and clams), and bivalves were the group most studied (76.67%). Sponges (91 to 612 items g – 1 DW) and polychaetes (1 to 880 items g–1 WW) had the highest number of MPs. Although it is possible to establish relationships between feeding mechanisms and MPs accumulation, using distinct methodologies makes comparing the results of different studies difficult, leading to an urgent call for standardizing methods for microplastic studies in marine organisms.

Morphological examination of recently collected barnacle specimens confirms the presence of Tesseropora atlantica (Cirripedia, Balanomorpha, Tetraclitidae) along the coastlines of Lanzarote and Fuerteventura, the easternmost islands of the Canary Archipelago. This constitutes the first documented occurrence of T. atlantica in the Canary Islands and establishes a new southern range limit for this relict species in the eastern Atlantic Ocean. Additionally, 16S and COI mitochondrial gene sequences were obtained for the first time for this species, allowing comparisons with related taxa. The study also explores plausible hypotheses concerning the species’ arrival in the Canary Islands.

This study aims to determine the age and growth of Anguilla anguilla from Lake Bafa, Türkiye. A total of 128 samples of European eel were purchased from a small-scale fisherman who caught them in Lake Bafa in November 2016 and 2017, using 34-mm mesh size and 15-m-long fyke nets. The total length (TL) and total weight were measured, and the sex, age, and life stage were identified. The mean TL for females was 54.1 ± 10.1 (36.1–76.2) cm, and for males 43.6 ± 3.7 (35.7–47.8) cm. Yellow and silver eel mean TLs were 48.9 ± 6.6 (35.7–63.7) and 61.9 ± 10.8 (39.9–77.2) cm, respectively, and for pooled data 53.3 ± 10.3 (35.7–77.2) cm. The growth for pooled samples was positive allometric. The age of eels varied from 2 to 9 years. The Von Bertalanffy growth parameters for pooled specimens were determined as L∞ = 71.9 cm, K = 0.25, and t0 = −0.11. The sex ratio (M:F = 1:11.2) was biased in favour of females. It is inferred from this and other studies that eels in Türkiye have comparable length and age distributions in similar habitats.

Deep-sea trawl samples collected from the west coast of India have revealed several previously undetected species inhabiting the deep waters. This study reports the first record of Bathycongrus nasicus from the western Indian waters and the second record from the entire western Indian Ocean. A single specimen of B. nasicus was collected from the Neendakara fishery harbour in southern Kerala. The species identity was confirmed morphometrically by comparing it with previous records, and the study provides the first molecular identification of this rare congrid eel. The presence of B. nasicus in the western Indian waters suggests its potential distribution throughout the northern Indian Ocean, with prior records from the Bay of Bengal and the western Arabian Sea. This new record indicates that there might be occurrences of several previously unknown fish species in the non-commercial fishery of this region, underscoring the importance of survey collections of non-commercial fishes, which play a crucial role in marine ecosystems.

We are in the early stage of a revolution in the field of comparative genomics. Within the past five years, thousands of animal, plant, and fungal genomes have been sequenced and assembled to high quality. There is even serious discussion around sequencing the genomes of every eukaryotic species on earth. Here, I explain why this genomic revolution is happening and discuss the feasibility of sequencing genomes on a massive scale. Having a very wide diversity of genome sequences will accelerate applied research in biomedicine, biotechnology, aquaculture, agriculture, and conservation, and facilitate fundamental research in areas such as ecology, physiology, developmental biology, and evolutionary biology. In this article, I explore new findings and new questions in evolutionary biology emerging from animal genome analyses. Examples are drawn from marine animals such as polychaetes, bivalves, cephalopods, fish, and bryozoans, plus unusual terrestrial groups such as gerbils, moths, and bee-flies. I highlight patterns of mutation, the dynamics of gene families, and chromosomal organisation of genomes as areas ripe for further research. An even wider diversity of genome sequences will be needed to fill the knowledge gaps or investigate emerging puzzles, and a case is made for sequencing the genomes of over 100,000 species.

We report the introduction of Juxtacribrilina mutabilis, a nonindigenous marine encrusting bryozoan, to eastern Canada. Previously reported as a nonindigenous species (NIS) in Europe and Maine, USA, this species is of potential ecological concern due to its propensity to foul eelgrass (Zostera marina), an ecologically important habitat-forming coastal species. By compiling prior unpublished records, re-evaluating existing specimens, and collecting new records of J. mutabilis, we discovered that the species has a widespread distribution in eastern Canada. Specimen reclassification efforts in our study indicate that J. mutabilis has been present in eastern Canada since at least 2013, but the species largely escaped notice until 2024, likely due to its similarity to other encrusting bryozoan species and other factors inhibiting its detection. In light of the distributional and genetic data collected in this study, we reconstruct the possible invasion history of J. mutabilis in eastern Canada, including potential introduction mechanisms, timing, and source regions. We also discuss the ecology of J. mutabilis in eastern Canada, evaluating the factors influencing the morphology of the bryozoan, assessing its potential to detrimentally impact its eelgrass substrate, and estimating its environmental niche. Further research into the distribution, ecology, and potential impacts of J. mutabilis in eastern Canada is recommended. This case study highlights the importance of diversity in the habitats surveyed and methods used when monitoring for marine NIS, the need for horizon scanning to raise awareness of potential NIS, and the advantages of multi-party collaboration and citizen science for early detection of such species.

This study is the first report on the monotypic Codonaria cistellula (Fol, 1883) Kofoid & Campbell, 1939 from the North-Eastern Arabian Sea (NEAS), Indian Ocean. The species was recorded at a water temperature of 25–26 °C and a salinity of 36‰, from a depth of 75–100 m in the NEAS. Two morphotypes were encountered from the region, yet the lorica opening diameter (LOD) remained within a narrow range of 46–50 µm. Moreover, as the original description lacks information on LOD, the circumscription of the species is difficult due to the lorica polymorphism, warranting further genetic analyses.