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- Pilot studies for stock enhancement of purple sea urchins (Paracentrotus lividus, Lamarck, 1816): usefulness of refuges and calcein marking for the monitoring of juveniles released into the natural environmentPublication . Correia, Maria João; Lopes, Patrícia Mega; Santos, Pedro M.; Jacinto, David; Mateus, David; Maresca, Francesco; Quintella, Bernardo Ruivo; Cruz, Teresa; Lourenço, Sílvia; Pombo, Ana; Costa, José LinoIn the framework of stock enhancement, field experiments were conducted between March and July 2021 in rocky shores of Central Portugal to test the usefulness of refuges and calcein marking for juvenile sea urchins releases. Individuals with 10–20mmin test diameter were captured in nature and tagged through immersion in a calcein bath with a concentration of 150 mg L 1, during 48 hr. Artificial shelters were used to provide refuge and an acclimatization structure for the released sea urchins, and in situ monitoring was carried out by counting the marked specimens over three months. Results point out to the importance of using shelters to provide protection to sea urchins, and validated the efficiency of the calcein tagging protocol for in situ monitoring. Sea urchins’ test diameter growth during the experiment was estimated to be 0.470mm month 1 (SD = 0.181).
- Modulation of different kelp life stages by herbivory: compensatory growth versus population decimationPublication . Franco, Joao N; Wernberg, Thomas; Bertocci, Iacopo; Jacinto, David; Maranhão, Paulo; Pereira, Tânia; Martinez, Brezo; Arenas; Francisco; Sousa-Pinto, Isabel; Tuya, FernandoPartitioning the efects of herbivory on diferent life stages of primary producers is key to understanding the population-wide consequences of herbivory. We assessed the performance of microscopic (MiS <1 mm) juveniles, macroscopic (MaS) juveniles and adult kelp (Laminaria ochroleuca) under contrasting herbivory regimes through a herbivore exclusion feld experiment. The abundance of MiS and the survival of MaS decreased by 67 and 63%, respec tively, when herbivorous fshes and sea urchins were present. Blade growth (linear and area) of adult kelp displayed con trasting patterns under herbivore pressure: a 60% increase and a 46% decrease, respectively. These results indicate that while herbivory severely reduces juvenile survival, it may also induce compensatory growth (measured as linear growth) in adult kelp. In summary, we here demonstrate how herbivory afects all sporophyte life stages of the kelp L. ochroleuca. This is likely to have important implications for situations where historical patterns of herbivore presence and herbivory are changing, such as is increasingly the case in many temperate regions due to warming around the world.