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ABSTRACT There is an apparent contradiction between the sedentary lifestyle and direct development of meiofaunal organisms and their widely observed distribution. This study is situated within the theoretical framework of ecological connectivity, metacommunities, and the impact of substrate type, particularly in the unique context of oceanic islands, offering a crucial perspective to unravel the complexities of meiofaunal dispersal and connectivity. We here studied the spatial distribution of meiofauna on natural and artificial beaches of an oceanic island, that is, Gran Canaria (Canary Is., NE Atlantic Ocean). The results revealed higher abundance and richness of meiofauna on artificial substrates compared to natural ones, with nematodes, copepods, and annelids being the dominant groups. The meiofaunal community composition differed significantly between natural and artificial beaches, suggesting colonisation of artificial beaches by natural beach communities. Notably, certain species were exclusively found on artificial beaches. The study highlighted the importance of substrate type in influencing meiofaunal composition, with artificial beaches providing new ecological niches and resources for meiofauna. The dissimilarity between beaches was attributed to morphospecies exclusive to either artificial or natural substrates, emphasising the role of dispersal mechanisms. These findings contribute to understanding the metacommunity dynamics of meiofauna in oceanic islands and call for further research on dispersal potential and biogeography. [ABSTRACT FROM AUTHOR]

ABSTRACT Free‐living marine nematodes play crucial roles in the benthic ecosystem and serve as valuable bioindicators for monitoring environmental stress. We explore the community structure of free‐living marine nematodes in the beach ecosystem near Bandar Abbas port city of Iran. The research focused on assessing the impact of domestic and industrial influences during winter and summer seasons in 2018 and 2019. Three coastal locations, namely KhurGursuzan (KG), Power Plant (PP), and Resalat (RE), were sampled, with KG under domestic wastewater influence, PP characterized by industrial activities, and RE serving as the control site. A total of 41 nematode genera were identified during the study, and dominant genera varied across locations, namely, Daptonema, Sabatieria, Promonhystera, Ptycholaimellus, and Eleutherolaimus at KG; Spirinia, Chromadorina, Terschellingia, Eleutherolaimus, and Promonhystera at PP; and Oncholaimus, Pomponema, Viscosia, Ptycholaimellus, Daptonema, and Eleutherolaimus at RE. These dominant genera accounted for 80% of the total nematode community during the sampling periods. The study revealed significant differences in abundance and genus diversity among the sites, with pollution‐affected sites exhibiting the lowest nematode diversity. Sediment granulometry showed a positive correlation with genus diversity across the sites, and the structure of the nematode assemblage was negatively influenced by polychlorinated biphenyls and total organic matter. Surprisingly, the spatial patterns in nematode assemblage structure and diversity remained consistent across both studied years. These findings contribute to our understanding of marine ecosystem health and the role of free‐living nematodes as bioindicators in the Persian Gulf. [ABSTRACT FROM AUTHOR]

Several artisanal fisheries target deepwater species. These stocks are highly sensitive to overfishing because of their slow growth and late maturation. This vulnerability is higher if species concentrate during spawning season in coastal areas, as occur with scabbardfish (Aphanopus spp.). In this paper, we explore if two Aphanopus species (A. carbo and A. intermedius) that coexist show migration patterns to coastal areas during spawning. We analysed specimens of both species throughout 4 years (2014-2017) in a weekly basis and compare morphological parameters with the distance of the coast (coastal (12 n.m.)). Both species showed coastal patterns of migration during the spawning season (October-December), with 65.90% of total specimens of A. carbo and 51.60% of A. intermedius being caught at Plusieurs peches artisanales ciblent des especes d'eau profonde, des stocks tres sensibles a la surpeche en raison de leur croissance lente et de leur maturation tardive. Cette vulnerabilite est plus grande si les especes se concentrent en zones cotieres durant la periode de frai, comme c'est le cas des sabres (Aphanopus spp.). Nous examinons si deux especes d'Aphanopus (A. carbo et A. intermedius) qui coexistent presentent des motifs de migration vers des zones cotieres durant la periode de frai. Nous avons analyse des specimens des deux especes pendant quatre annees (2014-2017) sur une base hebdomadaire et comparons des parametres morphologiques a la distance par rapport a la cote (zone cotiere (12 n.m.)). Les deux especes presentent des motifs de migration en zone cotiere durant la periode de frai (d'octobre a decembre), 65,90 % de tous les specimens d'A. carbo et 51,60 % des specimens d'A. intermedius etant peches a, Introduction Overfishing persists in many developed and developing countries worldwide (Pauly and Zeller 2016; Zeller et al. 2018). The effects of overfishing are not identical around the globe and are [...]