Identifying key environmental variables of two seahorse species (Hippocampus guttulatus and Hippocampus hippocampus) in the Ria Formosa lagoon, South Portugal

AbstractAfter seahorse population fluctuations were revealed in previous studies, probably due to changes in their natural habitat, this study sought to determine the current status of the populations of the two existing seahorse species in the Ria Formosa lagoon, by revisiting previously surveyed sites, while assessing the main drivers for detected changes. Hippocampus guttulatus densities decreased significantly between 2002 and 2008, followed by a significant increase between 2008 and 2012 and a significant decrease between 2012 and 2018. There were no significant differences in H. guttulatus populations between the 2002 and 2012 surveys, and between 2008 and 2018. As for Hippocampus hippocampus, there were no significant differences comparing densities from all the different dates. Among the different variables tested in this study, holdfast coverage seems to have played a crucial role in seahorse decline. It is important to further assess the impact on seahorse populations of two recently reported events, the illegal fishing of seahorses and the expansion of Caulerpa prolifera algae in the Ria Formosa lagoon, South Portugal. Considering the existent threats and the probable causes behind the recent seahorse abundance decline, seahorses’ low densities make them even more susceptible to local extirpation due to continuous threats, which emphasizes the dire urgency to put in place mitigative actions to contribute to the conservation of these iconic species.

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Effects of anthropogenic noise as a source of acoustic stress in wild populations of Hippocampus guttulatus in the Ria Formosa, south Portugal

Aquatic Conservation Marine and Freshwater Ecosystems ◽

10.1002/aqc.3056 ◽

2019 ◽

Vol 29 (5) ◽

pp. 751-759 ◽

Cited By ~ 2

Author(s):

Jorge Palma ◽

Marisa Magalhães ◽

Miguel Correia ◽

José Pedro Andrade

Keyword(s):

Anthropogenic Noise ◽

Wild Populations ◽

Acoustic Stress ◽

Hippocampus Guttulatus ◽

Ria Formosa ◽

South Portugal

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Assigning Hippocampus guttulatus recruits to the populations of origin using microsatellites: results from a field study in the Ria Formosa (south Portugal)

10.7287/peerj.preprints.1794 ◽

2016 ◽

Author(s):

José P Andrade ◽

Céline Madeira ◽

Miguel Correia ◽

Jorge Palma

Keyword(s):

Software Package ◽

Genetic Data ◽

Pilot Scale ◽

Sampling Protocol ◽

Preliminary Results ◽

Hippocampus Guttulatus ◽

Ria Formosa ◽

Standard Procedures ◽

Polymorphic Microsatellite ◽

South Portugal

The deployment of Artificial Holdfast Units (AHU) has been demonstrated as an effective tool for creating holdfast and sheltering conditions for Hippocampus guttulatus in the Ria Formosa (South Portugal). Preliminary results obtained with a pilot-scale AHU showed a high settlement rate, with recorded densities of up to 13.1 individuals.m-2. With the present study, we aim to understand weather the AHU’s contributed to attract new H. guttulatus recruits or concentrate those previously existing in these areas. Prior to the deployment of the AHU’s in a total of four focal sites, a sample of the skin filaments was collected from each H. guttulatus (n= 70) sighted in those locations. The same sampling protocol was later carried out on the recruits (n=14) sighted in one pilot-scale AHU since its deployment. Upon DNA extraction the variation of 13 highly polymorphic microsatellite loci isolated for H. guttulatus (or obtained by cross-amplification in H. hippocampus) has been analyzed. PCR reactions with labeled primers were performed using standard procedures and amplified products were run on an ABI PRISM 3130 XL Genetic Analyser©. Based on the genetic data, ONCOR software package was used to estimate the population of origin of recruits. Preliminary results indicate that more than 90% of the recruits at the AHU were assigned to the sites located up to 500 meter apart. No assignment has been demonstrated for the other sampled locations, situated further away from the AHU.

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Assigning Hippocampus guttulatus recruits to the populations of origin using microsatellites: results from a field study in the Ria Formosa (south Portugal)

10.7287/peerj.preprints.1794v1 ◽

2016 ◽

Author(s):

José P Andrade ◽

Céline Madeira ◽

Miguel Correia ◽

Jorge Palma

Keyword(s):

Software Package ◽

Genetic Data ◽

Pilot Scale ◽

Sampling Protocol ◽

Preliminary Results ◽

Hippocampus Guttulatus ◽

Ria Formosa ◽

Standard Procedures ◽

Polymorphic Microsatellite ◽

South Portugal

The deployment of Artificial Holdfast Units (AHU) has been demonstrated as an effective tool for creating holdfast and sheltering conditions for Hippocampus guttulatus in the Ria Formosa (South Portugal). Preliminary results obtained with a pilot-scale AHU showed a high settlement rate, with recorded densities of up to 13.1 individuals.m-2. With the present study, we aim to understand weather the AHU’s contributed to attract new H. guttulatus recruits or concentrate those previously existing in these areas. Prior to the deployment of the AHU’s in a total of four focal sites, a sample of the skin filaments was collected from each H. guttulatus (n= 70) sighted in those locations. The same sampling protocol was later carried out on the recruits (n=14) sighted in one pilot-scale AHU since its deployment. Upon DNA extraction the variation of 13 highly polymorphic microsatellite loci isolated for H. guttulatus (or obtained by cross-amplification in H. hippocampus) has been analyzed. PCR reactions with labeled primers were performed using standard procedures and amplified products were run on an ABI PRISM 3130 XL Genetic Analyser©. Based on the genetic data, ONCOR software package was used to estimate the population of origin of recruits. Preliminary results indicate that more than 90% of the recruits at the AHU were assigned to the sites located up to 500 meter apart. No assignment has been demonstrated for the other sampled locations, situated further away from the AHU.

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Salt marshes adjustment to anthropogenic pressures and sea-level rise

10.5194/egusphere-egu21-9107 ◽

2021 ◽

Author(s):

A. Rita Carrasco ◽

Katerina Kombiadou ◽

Miguel Amado

Keyword(s):

Sea Level Rise ◽

Sea Level ◽

Salt Marshes ◽

Anthropogenic Pressures ◽

The Past ◽

Ria Formosa ◽

Sediment Loads ◽

Human Interventions ◽

South Portugal ◽

And Sea Level

It is predictable that salt marshes in regions, where sediment loads are high, should be stable against a broader range of relative sea level scenarios than those in sediment-poor systems. Despite extensive theoretical and laboratory studies, additional syntheses of marsh &#8216;persistence&#8217; indicators under human interventions and accelerated sea-level rise rates are still needed. This study investigates the recent lateral changes occurring in lagoon-type marshes of the Ria Formosa lagoon (south Portugal) in the presence of human interventions and sea-level rise, to identify the major drivers for past marsh evolution and to estimate potential future trends. The conducted analysis assessed the past geomorphological adjustment based on imagery analysis and assessed its potential future adjustment to sea-level rise (~100 years) based on modelled land cover changes (by employing the SLAMM model within two sea-level rise scenarios).Salt marshes in the Ria Formosa showed slow lateral growth rates over the last 70 years (<1 mm&#8729;yr-1), with localized erosion along the main navigable channels associated with dredging activities. Higher change rates were noted near the inlets, with stronger progradation near the natural inlets of the system, fed by sediment influx pulses. Any potential influence of sea-level increase to an intensification of marsh-edge erosion in the past, could not be distinguished from human-induced pressures in the area. No significant sediment was exchanged between the salt marshes and tidal flats, and no self-organization pattern between them was observed in past. The related analysis showed that landcover changes in the salt marsh areas are likely to be more prominent in the future. The obtained results showed evidence of non-linearity in marsh response to high sea-level rise rates, which could indicate to the presence of critical thresholds and potential negative feedbacks within the system, with significant implications to marsh resilience.

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