Near-shore distribution of phyllosomas of the two only lobster species (Decapoda: Achelata) present in Robinson Crusoe Island and endemic to the Juan Fernández archipelago

Abstract

Two lobster species coexist in the southeast Pacifi c Juan Fernández archipelago, Jasus frontalis (Milne-Edwards, 1837) and Acantharctus delfi ni (Bouvier, 1909). Like most lobster species they undergo a prolonged larval period, which is particularly long for J. frontalis (> 16 months). Though typical of Palinurids, this long larval duration is usually not thought to be conducive to local recruitment. While it is known that settlement is confi ned to the three islands of the archipelago (Robinson Crusoe, Alejandro Selkirk and Santa Clara) and Desventuradas Islands (aprox. 800 km to the north), it remains poorly understood how local larval supply allows such distribution pattern. The goal of this study is twofold. Firstly, we aimed to characterize the distribution and abundance of the larvae of these two species around Robinson Crusoe Island using plankton tows and systematic hydrographic records between October 2008 to March of 2011, thus providing the fi rst systematic and prolonged coupled biophysical observations in the nearshore of the archipelago. We hypothesize that spatial and temporal larval distribution patterns are associated to their retention around the archipelago, thus contributing to our knowledge of the physical and biological processes maintaining their extreme isolation. Secondly, using molecular genetics, we confi rm a simple taxonomic criteria to distinguish the larvae of the two species, thus aiding future studies of larval dynamics. Throughout phyllosomas of A. delfi ni were more abundant than that of J. frontalis. Both species were more abundant on the northern shores of Robinson Crusoe Island and generally associated with warmer and saltier waters and mostly present in the samples collected during spring and summer months. Phyllosomas of both species were more abundant during nighttime tows in the upper layer of the water column surveyed suggesting a diurnal vertical migration behavior which, for coastal dwelling meroplanktonic species, can be related to a nearshore larval retention mechanism. These preliminary results represent a pioneering effort to understand the mechanisms driving the endemism and extreme isolation of the two study species.

Exploring overlooked components of remote South‐east Pacific oceanic islands: Larval and macrobenthic assemblages in reef habitats with distinct underwater soundscapes

“…Zooplankton surveys carried out during different field campaigns have also explored the pelagic environments around the Archipelago (e.g. Acuña et al, 2009;Landaeta & Castro, 2004;Palma et al, 2011;Rivera & Mujica, 2004a), and reported a similar group of species and abundances compared to those recorded here (i.e. with amphipods, ostracods, and decapod larvae exhibiting the higher numbers).…”

“…Even although cryptic fauna can account for up to two thirds of the reef's richness and are crucial components of regional biodiversity and conservation studies regarding the design of marine protected areas (Pearman et al, 2018), information on their biology and ecology in isolated south-east Pacific environments remain unexplored. Around the Juan Fernandez Archipelago and the RN Ecoregion, various efforts have increased knowledge in some of these cryptic components at both, the community level (Gusmao et al, 2018) as well as in specific taxonomic groups, including crustaceans (Meerhoff, Mujica, García, & Nava, 2017;Palma et al, 2011;Rivera & Mujica, 2004a, 2004b, fish (Acuña, Cabrera, & López, 2009;Landaeta & Castro, 2004), and molluscs (Cárdenas, Viard, & Castilla, 2008;Carrasco, Meerhoff, Yannicelly, & Ibáñez, 2019). Therefore, a different scenario may emerge when considering smaller and poorly studied organisms.…”

Patterns of genetic variation and life history traits of Zeuxapta seriolae infesting Seriola lalandi across the coastal and oceanic areas in the southeastern Pacific Ocean: potential implications for aquaculture

“…Tubbs et al [ 20 ] suggested an optimal temperature of 17.5 °C for the in vitro fecundity of Z. seriolae because egg production decreases at other temperatures yet sexual maturity is reached more quickly at higher temperatures. The seawater in NCC varies between 18 °C and 20 °C in summer [ 77 ] and between 14 °C (winter-autumn) and 20 °C (spring-summer) in the waters of JFA [ 78 ]. Therefore, it is possible that the local environmental conditions can modify the biological traits of Z. seriolae populations across the SEP; however, it is also possible that genetic differences among the parasite populations are reflected in different biological traits.…”

Modelacion de la conectividad de las subpoblaciones de la langosta de Juan Fernandez (Jasus frontalis), a traves de un modelo biofisico

“…El acoplamiento de estos factores reproductivos con las condiciones oceanográficas y meteorológicas imperantes en el período de liberación larval, es relevante en términos de la posible capacidad advectiva o de retención que podrían caracterizar al sistema de archipiélagos en este período. Palma et al (2011) indican que la baja abundancia de larvas tempranas de J. frontalis encontrada en varias zonas cercanas a la costa, durante el período de liberación larval, podría depender de los niveles de advección que caractericen a las corrientes. El aporte de estos factores reproductivos al éxito del asentamiento está determinado principalmente por la sobreposición espacio-temporal que existe entre ellos y los factores oceanográficos imperantes en las Tabla 3.…”