Modulation of gregarious settlement of the stalked barnacle, <em>Pollicipes pollicipes</em>: a laboratory study

Abstract

Summary:Although recruitment patterns of Pollicipes pollicipes (Crustacea: Scalpelliformes) in the wild have been investigated, no studies have yet focused on the factors that affect settlement. In the present paper, settlement of P. pollicipes on conspecifics (gregarious settlement) was investigated in the laboratory as a function of environmental conditions (hydrodynamics, temperature, light and salinity), larval age and batch. This study aimed to understand how these factors modulate settlement in the laboratory and elucidate how they might impact recruitment patterns in nature. Maximum attachment on adults was 30-35%, with a one-week metamorphosis rate of 70-80%. Batch differences affected both attachment and metamorphosis. Attachment rate was higher at natural salinity (30-40 psu), with lower salinity (20 psu) decreasing metamorphosis rate. Cyprid attachment was stimulated by light conditions and circulating water. This might relate to a preference for positioning high in the water column in nature, but also to increased cyprid-surface contact in conditions of circulating water. Older cyprids (3 or 6 days) showed higher attachment than un-aged larvae, though fewer 6-day-old larvae metamorphosed. Temperature did not affect attachment rate, but the metamorphosis rate decreased at 14°C (compared with 17 or 20°C), implying that differences in temperature during the breeding season can affect how quickly cyprids metamorphose to the juvenile. Cyprids survived for prolonged periods (≥20 days; 40% survival), likely due to efficient energy saving by intercalating long periods of inactivity with fast bursts of activity upon stimulation.Keywords: stalked barnacles; larva; settlement; attachment; metamorphosis; cyprids; aquaculture. Modulación del asentamiento gregario del percebe, Pollicipes pollicipes: un estudio de laboratorioResumen: Aunque se han investigado los patrones de reclutamiento de Pollicipes pollicipes (Crustacea: Scalpelliformes) en la naturaleza, actualmente no existen estudios sobre los factores que afectan al asentamiento larval. En el presente trabajo, el asentamiento de larvas de P. pollicipes sobre adultos conspecíficos (asentamiento gregario) fue investigado en el laboratorio en función de las variables ambientales (hidrodinamismo, temperatura, luz y salinidad), la edad y los distintos lotes de larvas. Este estudio tuvo como objetivo comprender cómo estos factores afectaban al asentamiento en el laboratorio y elucidar el modo en que podrían afectar a los patrones de reclutamiento en el medio natural. La fijación máxima en adultos fue de 30-35%, con una tasa de metamorfosis de 70 a 80% en una semana. Las tasas de fijación y de metamorfosis variaron dependiendo de los distintos lotes de larvas. La tasa de fijación fue superior cuando la salinidad era la natural (30-40 psu), mientras que la tasa de metamorfosis disminuía cuando la salinidad era inferior (20 psu). La fijación de la larva cipris se estimulaba en condiciones de luz y agua circulante, lo que puede estar relacionado con la preferencia po...

Quantitative analysis of the complete larval settlement process confirms Crisp's model of surface selectivity by barnacles

“…All rights reserved. settlement, we can design more effective, environmentally benign antifouling coatings to which they choose not to attach [11] or, indeed, stimulate settlement where this is desirable such as in the aquaculture of food species [12]. In practice, however, quantitative analysis of barnacle cyprid behaviour is a complex theoretical and practical challenge, and the software and hardware tools available to the field have so far proven inadequate (see Alsaab et al [13] for detailed discussion).…”

Effects of culture conditions on larval growth and survival of stalked barnacles ( Pollicipes pollicipes )

“…As there are currently no viable protocols for ensuring settlement on artificial substrata of P. pollicipes larvae in the laboratory (see Kugele & Yule ; Franco et al . ), it would also be prudent to build upon the present results and further investigate the implications of larval culture conditions towards competence to settle and ability to complete metamorphosis.…”

“…The few published investigations into culture conditions for P. pollicipes (e.g. Goldberg ; Coelho , ; Molares, Tilves & Pascual ; Molares, Tilves, Quintana, Rodríguez & Pascual ; Candeias ; Cribeiro ; Franco, Aldred, Sykes, Cruz & Clare ; Franco, Aldred, Cruz & Clare ) have often identified larval production and settlement as the main bottlenecks to production. Hatchery production is essential to ensure a regulated supply of larvae throughout the year with controlled timing and yield (Franco et al .…”

Effects of age, salinity and temperature on the metamorphosis and survival ofCapitulum mitellacyprids (Cirripedia: Thoracica: Scalpellomorpha)

“…Franco et al . (2016) investigated the effects of several factors on P. pollicipes settlement on conspecifics. Their results showed that a few different effects of factors on settlement exist between P. pollicipes and C. mitella .…”

“…The sole purpose of the cyprid stage is to locate, explore and attach on a suitable substratum, from where a subsequent complex metamorphosis takes place. Cyprid attachment and metamorphosis is also called ‘cyprid settlement’ (Clare & Matsumura, 2000; Harder et al ., 2001 a ; Franco et al ., 2016). For barnacles, attachment refers to the cementation and fixation of a cyprid onto a surface (Høeg et al ., 2012; Maréchal et al ., 2012; Spremberg et al ., 2012; Dreyer et al ., 2018), whereas metamorphosis denotes the subsequent sequence of morphological, physiological and biochemical events that transform a permanently attached cyprid into a sessile juvenile (Thiyagarajan, 2010; Maréchal et al ., 2012; Maruzzo et al ., 2012).…”