Search results for " marine"
showing 10 items of 1338 documents
Aggressive interactions between juvenile swordfishes and blue sharks in the Western Mediterranean: a widespread phenomenon?
2019
There are numerous reports of billfishes spearing objects, marine organisms, and even humans. Whether or not this behaviour is intentional and, if so, what is its functional meaning, are open questions. In 2016, an adult blue shark (Prionace glauca) was found to be killed by a juvenile swordfish (Xiphias gladius) in the western Mediterranean. Here we report on three more recent cases involving both species in the same area. In February 2017, an adult male blue shark was found stranded in Garrucha (Spain) with a fragment of a juvenile swordfish’s rostrum (18cm long x 2cm wide at proximal end) inserted in its cranium. In March 2017, an adult pregnant female blue shark was stranded alive on th…
Ultra- and microplankton assemblages as indicators of trophic status in a Mediterranean lagoon
2016
International audience; The seasonal abundance distribution of heterotrophic prokaryotes, pico-and nanophytoplankton, was investigated in connection with environmental variables and microplankton abundance at five stations in Ghar El Melh Lagoon (northeastern Tunisia). Flow cytometry analysis of ultraplankton resolved (i) five heterotrophic prokaryote groups labelled LNA1, LNA2 (low nucleic acid content), HNA1, HNA2 and HNA3 (high nucleic acid content) and (ii) at least 14 ultraphytoplankton groups assigned to picoeukaryotes, picoprokaryotes, nanoeukaryotes, cryptophyte-like cells and some unknown communities. Redundancy analysis (RDA) revealed (i) autumn-summer outbreaks of heterotrophic p…
Boat anchoring on Posidonia oceanica beds in a marine protected area (Italy, western Mediterranean): effect of anchor types in different anchoring st…
2004
Seagrasses worldwide are noted for suffering from mechanical damage caused by boat anchoring. This is particularly so in sites highly frequented by boaters (marine protected areas or coastal urbanised areas). In the last decades, different strategies have been put into practice to reduce such impacts on seagrasses (i.e. by anchoring bans or by deploying boat moorings), More recently, in consideration that few marine protected area (MPA) management bodies or local administrations have the resources to enforce their anchorage regulations, the self-regulatory approach based on education and information of boaters has been preferred in several cases. At present, however, very little is known on…
The increasing temperature as driving force for spatial distribution patterns of Parapenaeus longirostris (Lucas 1846) in the Strait of Sicily (Centr…
2020
Abstract The deep-water rose shrimp Parapenaeus longirostris (DPS), a demersal decapod representing the most important component of crustacean landings in the Mediterranean Sea, has been suggested as a species that may exhibit temperature-driven changes in the spatio-temporal dynamics. Considering that Mediterranean waters are warming up faster than oceans, understanding the relationships of DPS populations with temperature variations and the related changes in spatial patterns is absolutely key for its management. Using a long-term dataset covering 13-years from scientific surveys (International Bottom Trawl-Surveys in the Mediterranean, MEDITS; Italian national trawl surveys, GRUND) in th…
<strong><em>Grandidierella</em> <em>bonnieroides</em> Stephensen, 1948 (Amphipoda, Aoridae)—first record of an establis…
2016
The first record in the Mediterranean Sea of the invasive aorid amphipod crustacean Grandidierella bonnieroides is presented. A widespread circumtropical species, recorded off the Saudi coast of the Arabian Gulf, the Red Sea and the Suez Canal, it may have been introduced into the Mediterranean through the Suez Canal. This tube-builder species of soft bottoms recently established a population in the polluted Haifa Bay, Israel. Further, this is the first Mediterranean record of the genus.
First assessment of the rose shrimp, Parapenaeus longirostris (Lucas, 1846) in the central Mediterranean
1995
Abstract Between June 1989 and May 1990 a 1 year programme based on commercial samples and statistics was carried out to assess Parapenaeus longirostris in the Sicilian Channel (Central Mediterranean), since most trawl-fishing occurs outside the area currently covered by trawl surveys of the National Research Council Institute based in Mazara del Vallo. Fishing takes place on three distinct grounds, where three different sub-stocks belonging to the same population could be identified based on length and maturity data. Length-based methods allowed calculation of all parameters needed to fit Beverton and Holt's (1957) and Thompson and Bell's (1934) models, while natural mortality could be est…
Influence of the conservation status on carbon balances of semiarid coastal Mediterranean wetlands
2020
Permanent freshwater and brackish marshes are the typical wetland type of the Mediterranean Spanish coast. Historically, alterations to the original morphological and hydrological characteristics o...
Tropical CO2 seeps reveal the impact of ocean acidification on coral reef invertebrate recruitment
2017
Rising atmospheric CO2 concentrations are causing ocean acidification by reducing seawater pH and carbonate saturation levels. Laboratory studies have demonstrated that many larval and juvenile marine invertebrates are vulnerable to these changes in surface ocean chemistry, but challenges remain in predicting effects at community and ecosystem levels. We investigated the effect of ocean acidification on invertebrate recruitment at two coral reef CO2 seeps in Papua New Guinea. Invertebrate communities differed significantly between 'reference' (median pH7.97, 8.00), 'high CO2' (median pH7.77, 7.79), and 'extreme CO2' (median pH7.32, 7.68) conditions at each reef. There were also significant …
Effects of nutrient addition, recovery thereafter and the role of macrophytes in nutrient dynamics of a Mediterranean shallow lake: a mesocosm experi…
2017
Eutrophication in coastal wetlands has increased greatly because of human impact, reducing water quality and affecting aquatic plants. The aim of the present study was to investigate the eutrophication of Mediterranean wetlands and their possible recovery. An in situ mesocosm nutrient enrichment experiment was performed in a coastal shallow lake from eastern Spain, holding dense Chara meadows. In this lake, 36 mesocosms were installed and fertilised weekly with four levels of N and P addition over an 8-week period from June to August. Mesocosms fertilised with the two higher levels (N:P ≥5:0.5mgL–1) shifted to turbid status with macrophyte loss before Week 4. Saturation concentrations were…
Recruitment patterns in an intertidal species with low dispersal ability: the reef-building Dendropoma cristatum (Biondi, 1859) (Mollusca: Gastropoda)
2016
In the Mediterranean, the gastropod Dendropoma cristatum (sin. D. petraeum (Monterosato, 1884)) is the primary builder of the vermetid reef, an intertidal bioconstruction of exceptional ecological importance. Despite awareness of the need for conservation of this key species, the biology of D. cristatum remains poorly understood. The recruitment of D. cristatum deserves particular attention because the absence of a planktonic larval stage limits its dispersal ability. We examined the temporal pattern of recruitment during the breeding season of D. cristatum from June to September in 2013. Specifically, we compared the two portions of the vermetid reef (i.e. the inner edge and the outer edge…