Ruđer Bošković Institute - Muča, Rovinj

Restoration Project

Ruđer Bošković Institute - Muča, Rovinj

Restoration Objective:

We tested whether F. virsoides can be grown ex situ in laboratory conditions and planted into a location previously hosting the species, reintroducing the species on a small scale in order to assess survivability. Furthermore, we also explored whether there are any differences in growth regarding the upper and lower positioning of planting plots in the intertidal zone.

Site Selection Criteria:

The recruited individuals were planted in Muča, Rovinj, which previously hosted F. virsoides settlements.

Cause Of Decline:

The implied reason for the regression of all fucalean algae since the 1960s was the ever-increasing pollution and eutrophication of coastal waters [20,21,22]. Fucalean biomass in general was presumed to be recovering in some localities during the late 1990s and early 2000s, with F. virsoides included [19,23,24]. However, while some fucalean species in the northern Adriatic were recovering well into the 2010s, F. virsoides regressed again, for example completely disappearing from the Slovenian coast [9,25].

Key Reasons For Decline:

Water Pollution

Scientific Paper

First Restoration Experiment for Endemic Fucus virsoides on the Western Istrian Coast—Is It Feasible?

Gljušćić, E., Bilajac, A., Smith, S. M., Najdek, M., & Iveša, L. (2023).https://www.mdpi.com/2223-7747/12/7/1445

Organisation:

Ruđer Bošković Institute

Site Observations:

Observation Date

1st Nov 2021 – 1st Nov 2022

Action Summary:

Fertile receptacles were collected from a surviving population, seeded onto limestone tiles ex situ, and outplanted to a nearby historical kelp site in two caged intertidal plots, where recruits were monitored for 12 months.

Approximately 30 fertile receptacles from multiple donor individuals were collected and suspended in aerated aquaria containing unfiltered seawater, allowing zygotes to settle naturally onto limestone tiles, which were then cultured ex situ at 16–18 °C under LED lighting (148 μmol photons m⁻² s⁻¹; 12 h light/dark cycle) before being transferred to outdoor flow-through basins with natural seawater and fluorescent lighting for ~2 months prior to outplanting.

Seeded limestone stones (4 stones within a 100 cm² plot) were attached onto bedrock at the upper mid-tidal zone and enclosed in a protective mesh cage (12 × 12 × 10 cm; 1 cm mesh opening) to exclude grazers, with cages repaired and cleaned as needed

Lessons Learned:

Grazing caused major losses when cages failed, indicating that simple, scalable grazer-exclusion strategies or refuge sites (e.g., rock pools) are critical for future large-scale restoration.

Project Outcomes:

We showed that ex situ cultivation and planting of this species using a simple method is possible, at least at the small-scale. This was primarily successful due to the unpredictably fast growth of the F. virsoides after the planting and the resilience of the grown thalli. Even though the growth of the planted F. virsoides showed some differences according to the positioning in the intertidal zone, this does not present an obstacle for the possible further restoration attempts on the Istrian coast.

Nature of Disturbance:

In late August 2022, the protective cage on the lower position was destroyed by unknown means and fully grown, fertile thalli were exposed to grazers, which consumed most of the algal fronds, leaving only holdfasts

Area of Restoration (Ha)

0

Indicator Data:

Indicator:

Ending Value:

Starting Value:

Length

0.0706
m
0.0040
m
Transplant Info:
Life Stage:Juveniles
Source:Culture

Observation Date

1st Nov 2021 – 1st Nov 2022

Action Summary:

Fertile receptacles were collected from a surviving population, seeded onto limestone tiles ex situ, and outplanted to a nearby historical kelp site in two caged intertidal plots, where recruits were monitored for 12 months.

Approximately 30 fertile receptacles from multiple donor individuals were collected and suspended in aerated aquaria containing unfiltered seawater, allowing zygotes to settle naturally onto limestone tiles, which were then cultured ex situ at 16–18 °C under LED lighting (148 μmol photons m⁻² s⁻¹; 12 h light/dark cycle) before being transferred to outdoor flow-through basins with natural seawater and fluorescent lighting for ~2 months prior to outplanting.

Seeded limestone stones (4 stones within a 100 cm² plot) were attached onto bedrock at the lower mid-tidal zone (~3 m from the upper plot) and enclosed in a protective mesh cage (12 × 12 × 10 cm; 1 cm mesh opening) to exclude grazers, with cages repaired and cleaned as needed.

Lessons Learned:

Grazing caused major losses when cages failed, indicating that simple, scalable grazer-exclusion strategies or refuge sites (e.g., rock pools) are critical for future large-scale restoration.

Project Outcomes:

We showed that ex situ cultivation and planting of this species using a simple method is possible, at least at the small-scale. This was primarily successful due to the unpredictably fast growth of the F. virsoides after the planting and the resilience of the grown thalli. Even though the growth of the planted F. virsoides showed some differences according to the positioning in the intertidal zone, this does not present an obstacle for the possible further restoration attempts on the Istrian coast.

Nature of Disturbance:

In late August 2022, the protective cage on the lower position was destroyed by unknown means and fully grown, fertile thalli were exposed to grazers, which consumed most of the algal fronds, leaving only holdfasts

Area of Restoration (Ha)

0

Indicator Data:

Indicator:

Ending Value:

Starting Value:

Length

0.0384
m
0.0040
m
Transplant Info:
Life Stage:Juveniles
Source:Culture
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