Sandbar shark aggregation in the central Mediterranean Sea and potential effects of tourism

2021

An aggregation of sandbar sharks Carcharhinus plumbeus occurs every summer around the remote uninhabited islet of Lampione (Pelagie Islands Marine Protected Area, south-western Mediterranean Sea), attracting an increasing number of tourists for a shark watching experience. Despite the ecological and socio-economic importance of this rare occurrence in Mediterranean waters, there is a lack of scientific data and lack of information as to the potential impact of tourist activities on the presence and behaviour of this shark species. Using baited underwater videos, this study provides the first assessment of this shark aggregation, as well as a preliminary evaluation of the potential effects t…

Nest-mediated parental care in a marine fish: Are large-scale nesting habitats selected and do these habitats respond to small-scale requirements?

2018

Fishes have evolved various reproductive strategies including mechanisms that involve parental care and demersal eggs laid into nests. Symphodus ocellatus has a seasonal reproduction period during which large, dominant males become territorial and build nests with fragments of algae, where they attract females to spawn and provide care to the developing eggs. Based on the hypothesis that the S. ocellatus males choose the reproductive habitat based on some characteristics of the substrate, here we assessed whether, on a coastal area scale, the distribution of this species changes during the reproductive period because of the selection of some suitable sites or substrates, and whether the nes…

Ocean acidification affects somatic and otolith growth relationship in fish: Evidence from an in situ study

2019

Ocean acidification (OA) may have varied effects on fish eco-physiological responses. Most OA studies have been carried out in laboratory conditions without considering the in situ p CO 2 /pH variability documented for many marine coastal ecosystems. Using a standard otolith ageing technique, we assessed how in situ ocean acidification (ambient, versus end-of-century CO 2 levels) can affect somatic and otolith growth, and their relationship in a coastal fish. Somatic and otolith growth rates of juveniles of the ocellated wrasse Symphodus ocellatus living off a Mediterranean CO 2 seep increased at the high- p CO 2 site. Also, we detected that slower-growing individuals living at ambient p C…

Literature, social media and questionnaire surveys identify relevant conservation areas for Carcharhinus species in the Mediterranean Sea

2023

Sharks support ecosystems’ health, but their populations are facing severe declines worldwide. Knowledge gaps on shark distribution and the negative human perception of them still represent a barrier to the implementation of effective conservation measures. Here we carried out a regional-scale analysis in the Mediterranean Sea using data on requiem shark catches and sightings available in the scientific literature and on social media platforms to: 1) depict the distribution of Carcharhinus species across the basin, 2) identify potentially relevant areas for their conservation, and 3) evaluate people’s attitude toward shark protection. In addition, we administered 112 questionnaires in one o…

Mediterranean sharks and rays need action

2021

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Small-scale fisheries catch more threatened elasmobranchs inside partially protected areas than in unprotected areas.

2022

Elasmobranchs are heavily impacted by fishing. Catch statistics are grossly underestimated due to missing data from various fishery sectors such as small-scale fisheries. Marine Protected Areas are proposed as a tool to protect elasmobranchs and counter their ongoing depletion. We assess elasmobranchs caught in 1,256 fishing operations with fixed nets carried out in partially protected areas within Marine Protected Areas and unprotected areas beyond Marine Protected Areas borders at 11 locations in 6 Mediterranean countries. Twenty-four elasmobranch species were recorded, more than one-third belonging to the IUCN threatened categories (Vulnerable, Endangered, or Critically Endangered). Catc…

Limited behavioural effects of ocean acidification on a Mediterranean anemone goby (Gobius incognitus) chronically exposed to elevated CO2 levels

2022

An in situ reciprocal transplant experiment was carried around a volcanic CO2 vent to evaluate the anti-predator responses of an anemone goby species exposed to ambient (∼380 μatm) and high (∼850 μatm) CO2 sites. Overall, the anemone gobies displayed largely unaffected behaviors under high-CO2 conditions suggesting an adaptive potential of Gobius incognitus to ocean acidification (OA) conditions. This is also supported by its 3-fold higher density recorded in the field under high CO2. However, while fish exposed to ambient conditions showed an expected reduction in the swimming activity in the proximity of the predator between the pre- and post-exposure period, no such changes were detected…

Nest building in a Mediterranean wrasse (Symphodus ocellatus): are the algae used randomly chosen or actively selected?

2014

To increase their reproductive success, fish species have evolved various strategies, including both simple processes and more complex mechanisms that involve parental care by nest-building. In Symphodus ocellatus, a species that lives in rocky infralittoral zones of the Mediterranean Sea, during the reproductive period, the male builds a nest within a hole or crevice using fragments of algae and/or sand particles. Data on the nesting activity of wrasses are rare, and previous descriptions regarding the algal composition of nests have provided conflicting results. In this regard, it is unclear whether territorial males actively select algal species for nest construction or algal choice is r…

Nest guarding behaviour of a temperate wrasse differs between sites off Mediterranean CO2 seeps

2021

Abstract Organisms may respond to changing environmental conditions by adjusting their behaviour (i.e., behavioural plasticity). Ocean acidification (OA), resulting from anthropogenic emissions of carbon dioxide (CO2), is predicted to impair sensory function and behaviour of fish. However, reproductive behaviours, and parental care in particular, and their role in mediating responses to OA are presently overlooked. Here, we assessed whether the nesting male ocellated wrasse Symphodus ocellatus from sites with different CO2 concentrations showed different behaviours during their breeding season. We also investigated potential re-allocation of the time-budget towards different behavioural act…

Environmental DNA effectively captures functional diversity of coastal fish communities.

2020

Robust assessments of taxonomic and functional diversity are essential components of research programmes aimed at understanding current biodiversity patterns and forecasting trajectories of ecological changes. Yet, evaluating marine biodiversity along its dimensions is challenging and dependent on the power and accuracy of the available data collection methods. Here we combine three traditional survey methodologies (underwater visual census strip transects [UVCt], baited underwater videos [BUV] and small-scale fishery catches [SSFc]), and one novel molecular technique (environmental DNA metabarcoding [eDNA]-12S rRNA and cytochrome oxidase subunit 1 [COI]) to investigate their efficiency and…

Behavioural responses of fish groups exposed to a predatory threat under elevated CO2

2019

Most of the studies dealing with the effects of ocean acidification (OA) on fish behaviour tested individuals in isolation, even when the examined species live in shoals in the wild. Here we evaluated the effects of elevated CO2 concentrations (i.e. ∼900 μatm) on the shelter use and group cohesion of the gregarious damselfish Chromis viridis using groups of sub-adults exposed to a predatory threat. Results showed that, under predatory threat, fish reared at elevated CO2 concentrations displayed a risky behaviour (i.e. decreased shelter use), whereas their group cohesion was unaffected. Our findings add on increasing evidence to account for social dynamics in OA experiments, as living in gro…

CO2 EFFECTS ON SPAWNING RATES OF A MEDITERRANEAN NESTING WRASSE

2014

Some aspects of the reproductive behaviour of the ocellated wrasse Symphodus ocellatus (Forsskål 1775) were investigated in wild conditions along a pCO2 gradient. Our results show no differences in the number of females, sneakers and satellite males involved in the spawning phase under two pCO2 conditions. However, the spawning rate of nesting males was negatively affected in high pCO2, whilst exerted a normal reproductive pattern in ambient pCO2.

Effects of Ocean Acidification on physiology, behaviour and ecology of fish

CO2 concentration in the atmosphere is increasing at unprecedented rate since the last 800,000 years due to rising fossil fuel combustion, industrial processes and land use by humans. By absorbing part of this gas from the atmosphere, Oceans contribute to the mitigation of climatic changes, but at the cost of greater modifications of their physical and chemical characteristics. CO2 dissolved in the seawater leads to increased bicarbonate (HCO3 -) and hydrogen ions (H+) concentrations with a consequent pH drop, a phenomenon known as Ocean Acidification (OA). If global policy will not put in force mitigation measures to reduce CO2 emissions, it is projected that partial pressure of dissolved …

Supplementary material - Details on study area, species, methods and additional results from Ocean acidification affects somatic and otolith growth r…

2019

Ocean acidification (OA) may have varied effects on fish eco-physiological responses. Most OA studies were carried out in laboratory conditions without considering the in situ pCO2/pH variability documented for many marine coastal ecosystems. Using a standard otolith ageing technique, we assessed how in situ ocean acidification (ambient, versus end-of-century CO2 levels) can affect can affect somatic and otolith growth, and their relationship in a coastal fish. Somatic and otolith growth rates of juveniles from a population of the ocellated wrasse Symphodus ocellatus living off a Mediterranean CO2 seep, increased at the high-pCO2 site. Also, we detected that slower growing individuals livin…

Ocean acidification affects fish spawning but not paternity at CO2 seeps

2016

Fish exhibit impaired sensory function and altered behaviour at levels of ocean acidification expected to occur owing to anthropogenic carbon dioxide emissions during this century. We provide the first evidence of the effects of ocean acidification on reproductive behaviour of fish in the wild. Satellite and sneaker male ocellated wrasse ( Symphodus ocellatus ) compete to fertilize eggs guarded by dominant nesting males. Key mating behaviours such as dominant male courtship and nest defence did not differ between sites with ambient versus elevated CO 2 concentrations. Dominant males did, however, experience significantly lower rates of pair spawning at elevated CO 2 levels. Despite the hig…

Effects of ocean acidification on embryonic respiration and development of a temperate wrasse living along a natural CO2gradient

2016

We assessed rising CO2 effects on metabolism and development of a nesting wrasse by reciprocal transplant experiments in the field. Offspring brooded under different CO2 conditions exhibited similar responses. However, embryos from High-CO2 site were resilient to a wider range of pCO2 levels than those belonging to current-day conditions.

CO2 effects on behaviour and reproduction of nesting fish species

2014

Ocean acidification is a global phenomenon linked to the CO2 absorption by the surface of the sea. This increasing process leads to a rise of the CO2 partial pressure (pCO2) that changes the seawater chemistry. It is known that such changes have negative consequences for many marine organisms. However, the effects of acidification on fishes are yet poorly understood. Fishes have been hypothesized to be more physiologically tolerant to elevated CO2. Nevertheless, many researches have described severe effects of altered pCO2 levels on fish behaviour, especially during early life history stages, and only few authors have focused on fish reproduction. The aim of my Ph.D. research is to investig…

Changes in fish communities due to benthic habitat shifts under ocean acidification conditions

2020

Ocean acidification will likely change the structure and function of coastal marine ecosystems over coming decades. Volcanic carbon dioxide seeps generate dissolved CO2 and pH gradients that provide realistic insights into the direction and magnitude of these changes. Here, we used fish and benthic community surveys to assess the spatio-temporal dynamics of fish community properties off CO2 seeps in Japan. Adding to previous evidence from ocean acidification ecosystem studies conducted elsewhere, our findings documented shifts from calcified to non-calcified habitats with reduced benthic complexity. In addition, we found that such habitat transition led to decreased diversity of associated …

Ocean acidification does not impair predator recognition but increases juvenile growth in a temperate wrasse off CO2seeps

2017

8 pages, 4 figures, supplementary data https://doi.org/10.1016/j.marenvres.2017.10.013

Living in a high CO2 world: a global meta-analysis shows multiple trait-mediated fish responses to ocean acidification

2018

International audience; Understanding how marine organisms will be affected by global change is of primary importance to ensure ecosystem functioning and nature contributions to people. This study meets the call for addressing how life‐history traits mediate effects of ocean acidification on fish. We built a database of overall and trait‐mediated responses of teleost fish to future CO2 levels by searching the scientific literature. Using a meta‐analytical approach, we investigated the effects of projected CO2 levels by IPCC for 2050–2070 and 2100 on fish eco‐physiology and behavior from 320 contrasts on 42 species, stemming from polar to tropical regions. Moreover, since organisms may exper…

Influence of fish aggregating devices (FADs) on anti-predator behaviour within experimental mesocosms

2015

Commercial fishers have used fish aggregating devices throughout the Mediterranean Sea for over 40 years. These devices attract numerous predatory and forage species in both coastal and offshore environments. This study examined the influence of fish aggregating devices on schooling and aggregating behaviour by small forage fish in quasi-natural mesocosms. Anti-predator behaviour was evaluated for juvenile Caranx crysos under a variety of treatment conditions. Results suggest that, in the absence of physical structure, C. crysos first respond to a predatory threat by forming a school. When a physical structure is present, however, C. crysos show an occasional tendency to aggregate near the …

Data from: Living in a high CO2 world: a global meta-analysis shows multiple trait-mediated responses of fish to ocean acidification

2018

Understanding how marine organisms will be affected by global change is of primary importance to ensure ecosystem functioning and nature contributions to people. This study meets the call for addressing how life-history traits mediate effects of ocean acidification on fish. We built a database of overall and trait-mediated responses of teleost fish to future CO2 levels by searching the scientific literature. Using a meta-analytical approach, we investigated the effects of projected CO2 levels by IPCC for 2050-2070 and 2100 on fish eco-physiology and behavior from 320 contrasts on 42 species, stemming from polar to tropical regions. Moreover, since organisms may experience a mosaic of carbon…

Data from: Ocean acidification affects fish spawning but not paternity at CO2 seeps

2016

Fish exhibit impaired sensory function and altered behaviour at levels of ocean acidification expected to occur owing to anthropogenic carbon dioxide emissions during this century. We provide the first evidence of the effects of ocean acidification on reproductive behaviour of fish in the wild. Satellite and sneaker male ocellated wrasse (Symphodus ocellatus) compete to fertilize eggs guarded by dominant nesting males. Key mating behaviours such as dominant male courtship and nest defence did not differ between sites with ambient versus elevated CO2 concentrations. Dominant males did, however, experience significantly lower rates of pair spawning at elevated CO2 levels. Despite the higher r…

Ocean acidification affects fish spawning but not paternity at CO2 seeps

2016

Fish exhibit impaired sensory function and altered behaviour at levels of ocean acidification expected to occur owing to anthropogenic carbon dioxide emissions during this century. We provide the first evidence of the effects of ocean acidification on reproductive behaviour of fish in the wild. Satellite and sneaker male ocellated wrasse (Symphodus ocellatus) compete to fertilize eggs guarded by dominant nesting males. Key mating behaviours such as dominant male courtship and nest defence did not differ between sites with ambient versus elevated CO2 concentrations. Dominant males did, however, experience significantly lower rates of pair spawning at elevated CO2 levels. Despite the higher r…

Seawater carbonate chemistry and somatic and otolith growth relationship of Symphodus ocellatus

2019

Ocean acidification (OA) may have varied effects on fish eco-physiological responses. Most OA studies have been carried out in laboratory conditions without considering the in situ pCO2/pH variability documented for many marine coastal ecosystems. Using a standard otolith ageing technique, we assessed how in situ ocean acidification (ambient, versus end-of-century CO2 levels) can affect somatic and otolith growth, and their relationship in a coastal fish. Somatic and otolith growth rates of juveniles of the ocellated wrasse Symphodus ocellatus living off a Mediterranean CO2 seep increased at the high-pCO2 site. Also, we detected that slower-growing individuals living at ambient pCO2 levels …

Effects of ocean acidification on embryonic respiration and development of a temperate wrasse living along a natural CO2 gradient

2016

Volcanic CO2 seeps provide opportunities to investigate the effects of ocean acidification on organisms in the wild. To understand the influence of increasing CO2 concentrations on the metabolic rate (oxygen consumption) and the development of ocellated wrasse early life stages, we ran two field experiments, collecting embryos from nesting sites with different partial pressures of CO2 [pCO2; ambient (400 µatm) and high (800-1000 µatm)] and reciprocally transplanting embryos from ambient- to high-CO2 sites for 30 h. Ocellated wrasse offspring brooded in different CO2 conditions had similar responses, but after transplanting portions of nests to the high-CO2 site, embryos from parents that sp…

Database from Ocean acidification affects somatic and otolith growth relationship in fish: evidence from an in situ study.

2019

Ocean acidification (OA) may have varied effects on fish eco-physiological responses. Most OA studies were carried out in laboratory conditions without considering the in situ pCO2/pH variability documented for many marine coastal ecosystems. Using a standard otolith ageing technique, we assessed how in situ ocean acidification (ambient, versus end-of-century CO2 levels) can affect can affect somatic and otolith growth, and their relationship in a coastal fish. Somatic and otolith growth rates of juveniles from a population of the ocellated wrasse Symphodus ocellatus living off a Mediterranean CO2 seep, increased at the high-pCO2 site. Also, we detected that slower growing individuals livin…

Seawater carbonate chemistry and nest guarding behaviour of a temperate wrasse

2021

Organisms may respond to changing environmental conditions by adjusting their behaviour (i.e., behavioural plasticity). Ocean acidification (OA), resulting from anthropogenic emissions of carbon dioxide (CO2), is predicted to impair sensory function and behaviour of fish. However, reproductive behaviours, and parental care in particular, and their role in mediating responses to OA are presently overlooked. Here, we assessed whether the nesting male ocellated wrasse Symphodus ocellatus from sites with different CO2 concentrations showed different behaviours during their breeding season. We also investigated potential re-allocation of the time-budget towards different behavioural activities b…

Seawater carbonate chemistry and fish communities properties off CO2 seeps in Japan

2020

Ocean acidification will likely change the structure and function of coastal marine ecosystems over coming decades. Volcanic carbon dioxide seeps generate dissolved CO2 and pH gradients that provide realistic insights into the direction and magnitude of these changes. Here, we used fish and benthic community surveys to assess the spatio-temporal dynamics of fish community properties off CO2 seeps in Japan. Adding to previous evidence from ocean acidification ecosystem studies conducted elsewhere, our findings documented shifts from calcified to non-calcified habitats with reduced benthic complexity. In addition, we found that such habitat transition led to decreased diversity of associated …