Search

The large variation in vertebral shape and calcification observed among elasmobranch species prevents using a single method for enhancing growth bands and reading age. Further, estimating age and growth parameters can be difficult or impractical when samples are incomplete due to the bycatch of a size-selective fishery. Using a single and rapid method, age readings were obtained on the vertebrae of four batoid species, namely 53 individuals of Dasyatis pastinaca, 51 of Raja asterias, 15 of Torpedo marmorata, and 55 specimens of Torpedo torpedo, from the local small-scale trammel net fishery in the coastal waters (5–20 m depth) of the Central Tyrrhenian Sea during 2019–2021. Based on these data, a statistical routine was developed to obtain multiple estimates of age and growth parameters for incomplete samples due to size-selective fishing. The acceptable agreement between and within readers (intra and inter-reader disagreement < 5%) and the rate of increase in vertebral size with body size (differently ranked across species) demonstrated the consistency of the enhancing method. The parameters estimated by the Von Bertalanffy and Gompertz growth models matched the data available in the Mediterranean Sea for the species studied, with D. pastinaca, T. torpedo, and R. asterias showing the lowest (k = 0.05–0.12), intermediate (k = 0.112–0.19), and highest (k = 0.18–0.23) growth rates, respectively, in line with the life history traits of these species. Overall, the method proved effective both in delineating band pairs in vertebrae of different species and in reliably estimating the age and growth parameters of problematic samples due to size-selective fishing. The proposed method supports the collection of comparable demographic data from other areas where similar multi-specific assemblages are bycatch of size-selective fisheries impacting potential nursery areas and other essential habitats for elasmobranchs.

In recent years, the introduction of alien and invasive marine species in the Mediterranean Sea has rapidly increased. Laonome triangularis is a sabellid worm, native to the Australian coasts. Its first record in the Mediterranean Sea dates back to 2009 and, in this area, it is currently labeled as an allochthonous species. In the present work, we report the fìrst record of this polycheate in Italian waters and we provide some diagnostic features that are useful to identify the species.

The biocenosis of coarse sand and gravel exposed to bottom currents (SGCF) is the typical habitat of the amphioxus Branchiostoma lanceolatum (Pallas, 1774). This species and the habitat where it lives are threatened, and there are few reports of this biocenosis in the Italian and European waters. During a sampling survey carried out along the eastern Sicily coast (Ionian Sea) the macrozoobenthic community associated with this biocenosis was investigated. In this work, we report the presence of “Amphioxus sand” habitat in the Ionian Sicilian coast and the first record of the amphipod Megamphopus katagani Bakir, Sezgin and Myers, 2011 in the Italian waters.

Oenothera speciosa Nutt. is a non-indigenous plant that is widespread in Europe, South America, Asia, and Oceania. Although in its native range it is rarely pollinated by sphingid moths, in Europe and Asia, it was found to be associated with the hummingbird hawkmoth Macroglossum stellatarum (Linnaeus, 1758). However, the plant–insect interaction was negative, and the moths were found with proboscides stuck to the flowers of this plant. This interaction is a relevant conservation issue that requires further studies to assess its ecological impact. This work represents the first record of the negative interaction between O. speciosa and M. stellatarum in Italy.

In-depth studies on the effect of size and period in the diet of the hollow-snout grenadier Coelorinchus caelorhincus in the Mediterranean Sea are scant and incomplete. We obtained 75 specimens of this species from the discard of deep trawl fishing on the slope of the central Tyrrhenian Sea. As corollary data, we estimated the length–weight relationship, the size frequency distribution, and composition of sexual maturity stages of the sampled individuals. We deepened stomach content analysis aiming at the evaluation of size and period’s effect in the fish diet by Costello’s interpretation of dietary indexes and correspondence analysis. The corollary results suggested negative allometric growth (b = 2.69), an asynchronous reproductive strategy (paucity of mature individuals) and a size-related bathymetrical distribution for this species (prevalence of small and intermediate-sized specimens). The prey importance index (PII) revealed that the hollow-snout grenadier is a generalist feeder on cephalopods (PII: 0–1200), fish (PII: 0–1000), crustaceans (PII: 4000–6000), and polychaetes (PII: 400–1800), and a light specialist at population level on the dominant prey among them. At the micro-taxa level, the species was found to be a generalist feeder on 10 groups of rare prey and a light specialist at population level on amphipods (PII: 1300–3200). Overall, results indicated the presence of two feeding gradients that determined an intermingled effect of size and period on fish diet. In particular, intraspecific competition and stability of food resources appeared as the factors that significantly harmonize the diet of Coelorinchus caoelorhincus in the context of the ecotrophic constraints of a deep-sea species.

Biological invasions result in negative and unpredictable impacts on oceans worldwide. Non-indigenous macrophytes often synthesize secondary metabolites for defensive purposes and increased competition efficiency: this is the case of Caulerpa cylindracea, which has entered the Mediterranean Sea in 1990 and competed against local flora and fauna since. It was demonstrated that the white seabream Diplodus sargus (i) has included the algae into its diet, (ii) is subject to the peculiar Abnormally Tough Specimen (ATS) condition post-cooking, and (iii) suffers physiological and behavioral disturbances from caulerpin, one of the three major algal secondary metabolites. This paper confirms a feeding relationship between the fish and the algae, quantifies caulerpin accumulation in the liver, suggests a possible mollusk- and echinoderm-driven biomagnification, and highlights the fact that all ATS specimens were males. Multivariate analyses on a multi-biomarker panel reveals differential correlations to key cellular processes such as oxidative stress, metabolism, neurotoxicity, and lipid peroxidation as well as to condition indexes.

Ophelia roscoffensis Augener, 1910 is an opheliid worm identifiable by the number of anterior abranchiate chaetigers and the number of the gill pairs. Although it was already reported in the Mediterranean Sea, it has never been found in the Italian waters. This study represents the first record of Ophelia roscoffensis in the Italian waters. A total of 18 specimens were collected along the coast of Civitavecchia (Tyrrhenian Sea) in a Posidonia oceanica (L.) Delile bed at a depth of 7 m.

Goniadella bobrezkii (Annenkova, 1929) is a small goniadid worm identifiable by the number of anterior uniramous parapodia and by the position of the posterior spine-like notochetae arising dorsal to dorsal cirri. Although it was already reported in the Mediterranean Sea, it has never been found in the Italian waters. This study represents the first generic and specific record of G. bobrezkii along Italian coasts. A total of 25 specimens were collected in a Posidonia oceanica (L.) Delile bed, depth of 7 m, off Civitavecchia (Rome).

Marine plastic pollution is currently an issue of mounting concern around the world. Stomach content of marine fish has been increasingly used as a valid proxy for detecting the presence of such a pollutant in marine biota, both for coastal and deep-water environments. Although ingestion of microplastics has been reported in an increasing number of species, the patterns of ingestion still remain unclear, depending closely on the interaction between the species and types of microplastics involved. In this context, we analysed and compared the stomach contents of two bathyal dwelling opportunistic feeder species namely Galeus melastomus and Coelorinchus caelorhincus. In particular, we analysed microplastic items according to their dimension, morphology and colour, and diet’s variation with size obtained through prey identification. Both species showed a higher frequency of occurrence of the blue filament-like middle-sized microplastics (1.01–4.75 mm) compared with the other categories, although this pattern was much more marked in C. caelorhincus than in G. melastomus. The latter conversely showed a larger array of ingested plastic items in terms of shape and colour. Matching plastic ingestion with dietary data suggested potential predator confusion occurring in C. caelorhincus through active mis-selection of a defined type of microplastic instead of some particular family of polychaetes, which resemble in shape, size, and color to that type. Otherwise, G. melastomus appeared more prone to a random ingestion of a larger array of microplastic items because of a more generalistic and less selective feeding strategy. Although further validation is needed, stomach contents of the two species showed evidence strong enough to be considered as potential bioindicator species of microplastic pollution, as required by the Marine Strategy Framework Directive for monitoring this pollutant in the marine environment.