Long-term population status of two harvested intertidal grazers (Patella aspera and Patella candei), before (1996–2006) and after (2007–2017) the implementation of management measures

Sousa, Ricardo; Vasconcelos, Joana; Henriques, Paulo; Pinto, Ana Rita; Delgado, J. M. P. Q.; Riera, Rodrigo

doi:10.1016/j.seares.2018.11.002

Cited by 25 publications

(35 citation statements)

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“…slow growth, late maturity, and high longevity) together with the occurrence of illegal harvesting, especially on Garajau and Rocha do Navio. Additionally, the harvesting regulatory measures were implemented in 2006 and they have contributed to a slight recovery of the exploited populations stocks in this region and a reduction of the differences in size between exploited zones and MPAs (Sousa et al, ).…”

Section: Discussionmentioning

confidence: 99%

“…The removal of organisms for food, bait, aquariums, and shell collection for decorative purposes are human activities that most affect the mollusc populations in coastal zones (Ramírez, Tuya, & Haroun, ), resulting in direct and indirect disturbance of intertidal populations (Addessi, ; Kingsford, Underwood, & Kennelly, ; Lindberg, Estes, & Warheit, ). These disturbances essentially focus on the abundance, size structure, and alterations on the reproductive output and replenishment of the exploited populations as a result of the size‐selective nature of harvesting (Kido & Murray, ; Lindberg et al, ; Martins et al, ; Riera et al, ; Sousa et al, ). Larger specimens are the more attractive, visible, and prone to be caught, adding to their higher commercial value (Kido & Murray, ; Lindberg et al, ; Ramírez et al, ).…”

Section: Introductionmentioning

confidence: 99%

“…Their slow growth rate and long life contribute to these species being extremely vulnerable to exploitation. As such, the enforcement of existing harvest regulations is essential to prevent future overexploitation of these keystone species (Henriques et al, ; Sousa et al, ; Sousa, Delgado, Pinto, & Henriques, ).…”

Section: Introductionmentioning

confidence: 99%

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The protection effects of marine protected areas on exploited molluscs from an oceanic archipelago

Sousa

Henriques

Vasconcelos

et al. 2020

Aquatic Conservation

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1. Limpets are one of the most successful intertidal algal grazers in the north-eastern Atlantic. They provide valuable ecosystem services, playing a pivotal role in maintaining rocky shore ecological balance and have an important economic value, being subject to high levels of exploitation in several oceanic archipelagos.Limpets represent one of the most profitable economic activities of small-scale fisheries in the Madeira archipelago. However, limpets are extremely vulnerable to anthropogenic impacts, such as overharvesting, habitat fragmentation, and pollution.2. The protection effects and the effectiveness of marine protected areas (MPAs) on the population dynamics of two historically highly exploited limpet species, Patella aspera and Patella candei, were analysed through a comparative study of size, reproduction, and biomass in the Madeira archipelago.3. The effects of protection from MPAs on limpet populations resulted in a differential increase on size at first maturity, shell size, and capture per unit effort according to the degree of protection. 4. Old and enforced MPAs showed the best-preserved limpet populations in the study area, and both variables (age and enforcement) best explained the observed variability among the MPAs studied. 5.A thorough and multidisciplinary study is necessary to obtain a reliable picture of commercial stocks of the two targeted species (P. aspera and P. candei). Genetic analysis and studies on the food source of limpets may shed light to develop integrative conservation strategies.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The protection effects of marine protected areas on exploited molluscs from an oceanic archipelago

Sousa

Henriques

Vasconcelos

et al. 2020

Aquatic Conservation

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“…Patella aspera Röding, 1798 is a true limpet species (Patellogastropoda) native from the Macaronesian Region (Sousa et al., 2017) and an important gastronomic and economical resource for the regional economy (Fernandes et al., 2019; Sousa, Vasconcelos, Henriques, et al, 2019). Currently, the limpet populations are compromised by the overexploitation (González‐Lorenzo et al., 2015; Núñez et al., 2003), and legal regulations and management measures were imposed to reduce the anthropogenic impact and restore the native stocks in Madeira (Sousa, Vasconcelos, Henriques, et al, 2019; Sousa, Vasconcelos, Riera, et al, 2019), Azores (Serrão et al., 2010) and the Canary archipelagos (DECRETO 182/2004; Núñez et al., 2003).…”

Section: Introductionmentioning

confidence: 99%

Artificial maturation and larval production of the limpet Patella aspera Röding, 1798 (Patellogastropoda, Mollusca): Enhancing fertilization success of oocytes using NaOH‐alkalinized seawater

Castejón

Cañizares

Nogueira

et al. 2020

Aquaculture Research

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Patella aspera is a valuable limpet species native from the Macaronesian Region, which commercial exploitation is regulated due to overfishing. Aquaculture production of the species has the potential to be a sustainable alternative to the exploitation of this natural resource. This is the first study of the larval production of P. aspera with oocytes obtained from dissected gonads and artificially matured using NaOH‐alkalinized seawater. An artificial maturation experiment obtained the higher ratio of matured oocytes employing alkalinized seawater at pH 9.0 and 9.5 from 3 to 5 h. In vitro experiments combined similar artificial maturation conditions: pH 9 and 9.5 (plus pH 8 as control) during 1:30, 3:00 and 4:00 h; with three fertilization times (1:30, 3:00 and 24:00 h) to determine the combination of factors leading to higher larval production. Results show increased larval production, ranging from 50% to 75% total fertilized oocytes, using alkalinized baths at pH 9 from 3 to 4 h, followed by 24 h fertilization time at 19 ± 1°C. The present methodology ensures the production of P. aspera larvae, a mandatory step for further studies focused on the larviculture and aquaculture production of this limpet species.

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“…The harvest activity becomes progressively more intensive with the demographic increase of human settlement around the islands' coasts and with the technological progresses that simplify the access to the coast at previously inaccessible areas [1,2]. This long-term exploitation has changed the population dynamics, due to shifts on the abundance and/or size structure and density of the exploited marine gastropods over the years [3].…”

Section: Introductionmentioning

confidence: 99%

Artisanal Harvest of Shellfish in the Northeastern Atlantic: The Example of Limpet and Topshell Fisheries in the Archipelago of Madeira

Sousa¹,

Riera²,

Vasconcelos³

et al. 2020

Invertebrates - Ecophysiology and Management

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The harvesting of littoral benthic shellfish in the archipelago of Madeira dates back to the fifteenth century when the Portuguese discovered and colonized the archipelago. The consumption of littoral shellfish is part of the gastronomic cultural heritage of this region, appreciated by the local population and tourists, and has a high social and economic importance. Therefore, harvesting pressure on these resources is one of the greatest concerns, and as such, a sustainable exploitation based on proper regulation, considering the biological and ecological specificities of these species in their particular habitat, is crucial to promote the preservation of species and habitats at medium and long terms. This study presents the current harvesting management regime for gastropods in the archipelago of Madeira and characterizes the artisanal harvest through a period of 27 years providing new insights for future research in these topics. This artisanal harvesting operates mostly by small vessels (<10 m), with low tonnage and capacity, in nearby areas preferentially in the North coast of Madeira and around Desertas Islands. During the studied period, management actions resulted in the reduction of 50% of the vessels operating in the harvesting of limpets and in slight recovery of the stocks of limpets. The economic impact of limpets gradually increased over the years, representing in 2017 96% of the economic value landed for molluscs and 2% of the total landings in this region. The present characterization provides a comprehensive outlook of the evolution of the marine gastropod harvest in the archipelago of Madeira and allows future comparisons with other regions where gastropods are commercially exploited.

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Long-term population status of two harvested intertidal grazers (Patella aspera and Patella candei), before (1996–2006) and after (2007–2017) the implementation of management measures

Cited by 25 publications

References 35 publications

The protection effects of marine protected areas on exploited molluscs from an oceanic archipelago

The protection effects of marine protected areas on exploited molluscs from an oceanic archipelago

Artificial maturation and larval production of the limpet Patella aspera Röding, 1798 (Patellogastropoda, Mollusca): Enhancing fertilization success of oocytes using NaOH‐alkalinized seawater

Artisanal Harvest of Shellfish in the Northeastern Atlantic: The Example of Limpet and Topshell Fisheries in the Archipelago of Madeira

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