The ingestion of microplastics (MPs - plastic particles <5 mm) by planktivorous organisms represents a significant threat to marine food webs. To investigate how seasonality might affect plastic intake in oceanic islands' ecosystems, relative abundances and composition of MPs and mesozooplankton samples collected off Madeira Island (NE Atlantic) between February 2019 and January 2020 were analysed. MPs were found in all samples, with fibres accounting for 89 % of the particles. MPs and zooplankton mean abundance was 0.262 items/m³ and 18.137 individuals/m³, respectively. Their monthly variations follow the seasonal fluctuation of environmental parameters, such as currents, chlorophyll-a concentration, sea surface temperature and precipitation intensity. A higher MPs/zooplankton ratio was recorded in the warm season (May-Oct), reaching 0.068 items/individual when considering large-sized particles (1000–5000 μm). This is the first study to assess the seasonal variability of MPs in an oceanic island system providing essential information respecting its ecological impact in pelagic environments.

Existing marine bioregions covering the Pacific Ocean are conceptualised at spatial scales that are too broad for national marine spatial planning. Here, we developed the first combined oceanic and coastal marine bioregionalisation at national scales, delineating 262 deep-water and 103 reef-associated bioregions across the southwest Pacific. The deep-water bioregions were informed by thirty biophysical environmental variables. For reef-associated environments, records for 806 taxa at 7369 sites were used to predict the probability of observing taxa based on environmental variables. Both deep-water and reef-associated bioregions were defined with cluster analysis applied to the environmental variables and predicted species observation probabilities, respectively to classify areas with high taxonomic similarity. Local experts further refined the delineation of the bioregions at national scales for four countries. This work provides marine bioregions that enable the design of ecologically representative national systems of marine protected areas within offshore and inshore environments in the Pacific.

In the present paper it is presented application of Daily Egg Production Method (DEPM) to the anchovy (Engraulis encrasicolus L. 1758) stock in the open part of Montenegrin coast. This article is based on the research done within the frame of AdriaMed Project.

During the study we recorded narrow margins between zooplankton distribution and the ecological characteristics of water in Bokakotorska Bay (Adriatic sea, Montenegro). Various species show different vulnerability to environment quality. Some are defined as indicators, with low tolerance for the ecological variation of environment, and their distribution is limited to the particular type of water masses within the sea. The limiting factors are different for various species, and their indicator status is determined by their distribution. The indicator type, based on monitoring of particular species, may define a biotope, with the help of statistical analyses that identify the main time and spacial behavior patterns of a species, and my allow future ecosystem changes to be anticipated. In this paper we paid particular attention to the indicator species Oithona nana (Giesbrecht).