Browsing by Author "Fontes, Jorge"
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- Contrasting movements and residency of two serranids in a small Macaronesian MPAPublication . Afonso, P.; Abecasis, D.; Santos, Ricardo Serrão; Fontes, JorgeProtection inside marine reserves and the desired ‘reserve effect’ depend directly on the home rangeand sedentary behaviour of fishes throughout their lives. Benthic territorial predators are typically seenas major candidates to beneficiaries, but empirical evidence of short-versus long term residency is stillsurprisingly rare. We studied the inter-annual patterns of site fidelity and finer scale movements in twoof the most abundant benthic predators of the NE Atlantic coastal reefs, the dusky grouper (Epinephelusmarginatus) and the blacktail comber (Serranus atricauda), using passive acoustic telemetry inside andaround a small marine reserve in the Azores islands, central North Atlantic. Individuals of both speciesresided in the reserve year-round, occupying stable core activity areas within relatively small homeranges. Groupers were detected nearly every day (n = 11, median = 5.0 years) while combers were stilldetected in 2/3 of the days (n = 9, median = 2.0 years). Some dusky groupers underwent daily short-rangeforays during the summer, most probably related to spawning events, whereas combers appeared toforay for longer periods with no direct relation with reproductive activity. The two species also contrastin their diel pattern, strictly diurnal in the comber but crepuscular in the grouper. This study evidencesthat even small reserves within the size range of most coastal reserves can accommodate the multiple-scale patterns of space use of exploited benthic territorial species, and promote the recovery of theirlocal exploited populations in the long-term via the ‘reserve effect’ and, potentially, via the ‘larval export’effect.
- Global habitat predictions to inform spatiotemporal fisheries management: initial steps within the frameworkPublication . Bowlby, Heather D.; Druon, Jean-Noël; Lopez, Jon; Juan-Jordá, Maria José; Carreón-Zapiain, María Teresa; Vandeperre, Frederic; Leone, Agostino; Finucci, Brittany; Sabarros, Philippe S.; Block, Barbara A.; Arrizabalaga, Haritz; Afonso, Pedro; Musyl, Michael K.; Cortés, Enric; Cardoso, Luis Gustavo; Mourato, Bruno; Queiroz, Nuno; Fontes, Jorge; Abascal, Francisco J.; Zanzi, Antonella; Hazin, Humberto Gomes; Bach, Pascal; Sims, David W.; Travassos, Paulo; Coelho, RuiTuna Regional Fishery Management Organizations (tRFMOs) are increasingly interested in spatiotemporal management as a tool to reduce interaction rates with vulnerable species. We use blue shark ( Prionace glauca ) as a case study to demonstrate the critical first steps in the implementation process, highlighting how predictions of global habitat for vulnerable life stages can be transformed into a publicly -accessible spatial bycatch mitigation tool. By providing examples of possible management goals and an associated threshold to identify essential habitats, we show how these key areas can represent a relatively low percentage of oceanic area on a monthly basis (16-24% between 50 degrees S and 60 degrees N), yet can have relatively high potential protection efficiency (similar to 42%) for vulnerable stages if fishing effort is redistributed elsewhere. While spatiotemporal management has demonstrable potential for blue sharks to effectively mitigate fishing mortality on sensitive life stages, we identify inherent challenges and sequential steps that require careful consideration by tRFMOs as work proceeds. We also discuss how our single-species framework could be easily extended to a multispecies approach by assigning relative conservation risk before layering habitat model predictions in an integrated analysis. Such broader application of our approach could address the goals of tRFMOs related to reducing the ecosystem effects of fishing and pave the way for efficient fisheries co-management using an ecosystem-based approach.
- Intra- and interspecific associations in two predatory reef fishes at a shallow seamountPublication . Gandra, Miguel; Afonso, Pedro; Fontes, Jorgethe spatial dynamics of marine populations are shaped by habitat availability, environmental variability and individual interactions, particularly when multiple species share limited habitat such as patchy offshore reefs. the yellowmouth barracuda Sphyraena viridensis and the almaco jack Seriola rivoliana are the 2 most abundant bentho-pelagic reef predators in the Azores archipelago (central North Atlantic). They aggregate at shallow offshore seamounts, and largely share diet preferences, but very little is known about how habitat and resources are shared by these predators intra- and inter-specifically. Here we use long-term (over 3 yr) passive acoustic telemetry to investigate the patterns of activity, space use and associative behaviour at an isolated, small shallow seamount. By quantifying fine-scale spatiotemporal overlaps and performing null model randomization tests, we found evidence of non-random associations, mostly between conspecifics of both species, as well as shifts in diel and seasonal patterns of space occupancy. Both species were detected more often during spring, and appear to be more active during daytime, suggesting the absence of fine-scale temporal habitat partitioning. Additionally, we found evidence of size-dependent spatial behaviour in almaco jack, with similarly sized individuals co-occurring more often and larger specimens being more infrequently detected. This study quantitatively assesses individual associations using solely presence-absence data collected through passive acoustic telemetry, showing the potential of this approach in a broader application to a significant number of past and ongoing studies, even if many were not originally designed to study this important aspect of fish ecology.
- On some interesting opisthobranchs (Mollusca, Gastropoda) from the AzoresPublication . Fontes, Jorge; Tempera, Fernando; Wirtz, PeterThe nudibranch Eubranchus farrani Alder and Hancock, 1844 is recorded from the Azores for the first time. The presence of the sacoglossan Placida cremoniana (Trinchese, 1892) in the Azores is confirmed. Pleurobranchus sp. from the Azores, Madeira and the Canary Islands is compared with P. garciagomesi Cervera et al. 1996; it probably is an undescribed species.
- ‘Solo datasets’: unexpected behavioural patterns uncovered by acoustic monitoring of single individualsPublication . Baeyaert, Joffrey; Abecasis, David; Afonso, Pedro; Graça, Gonçalo; Erzini, Karim; Fontes, JorgeA holistic understanding of the life-history strategies of marine populations is often hindered by complex population dynamics, exacerbated by an intricate movement ecology across their life history (Nathan et al. 2008; Parsons et al. 2008; Jeltsch et al. 2013). Movement patterns and spatial ecology can vary spatially and temporally for different reasons, mainly related to the organism’s life history and environmental variability (Abecasis et al. 2009, 2013; Afonso et al. 2009). Changes in spatial use and movement can occur daily when visiting feeding grounds or avoiding predators, or seasonally, when sexually mature individuals migrate to spawning/breeding grounds (Kozakiewicz 1995; Sundström et al. 2001). However, observed shifts in spatial use and movement patterns, as a result of behavioural plasticity, may also vary greatly from one individual to another of the same species and/or population (Afonso et al. 2009). Further, ontogeny can also play an important role and explain a possible change in individual spatial variation. Noticeable differences in the behaviour and movements of mature and immature individuals have been documented in various marine organisms (Lowe et al. 1996; Lecchini and Galzin 2005). Permanent habitat shifts have been associated with ontogenesis in pigeye sharks (Carcharhinus amboinensis), moving from inshore to offshore areas after reaching maturity (Knip et al. 2011).
- The multi-annual residency of juvenile smooth hammerhead shark in an oceanic island nurseryPublication . Afonso, Pedro; Gandra, Miguel; Graça, Gonçalo; Macena, Bruno; Vandeperre, Frederic; Fontes, JorgeThe increased risk of local extinction becomes critical for sharks depending on the narrow and isolated coastal habitats of oceanic islands. This includes large pelagic oceanic sharks that use such habitats as nurseries, as previously hypothesized for the smooth hammerhead Sphyrna zygaena, the least known of cosmopolitan large hammerhead sharks. We used a combination of acoustic and satellite telemetry in a juvenile population of Faial and Pico islands, Azores, mid-north Atlantic, to confirm if this isolated archipelago holds nurseries, and to answer questions related to their function and spatial-temporal stability. Our long-term acoustic tracking data showed a cluster of individual core home ranges in specific areas of north shore Faial, and surface positions from five Argos-linked tagged individuals also showed a clustering overlap in those areas for up to 1 year. These patterns seem to reveal a true habitat preference within the Faial-Pico island (sub) population of juvenile smooth hammerhead shark, and thus constitute strong evidence for this area to be considered a nursery. Some individuals remained in this nursery for up to 4 years, especially during summers. Sharks also showed a strong diel behavior, typically using the inshore nurseries during the day and moving further offshore during the night, during which they increased activity and dove deeper, most possibly to feed. We speculate that a combination of increased feeding opportunities, expanded trophic niche, and reduced predatory pressure may be a key evolutionary driver for the existence, prolonged use, and even preference of coastal nurseries at oceanic islands by juvenile smooth hammerhead shark. Given that these nurseries may constitute essential fish habitat for this species, they should be explicitly included in spatial management measures at the local and regional scales, as they may also play a role of greater importance to the north Atlantic population of this oceanic species.