Retention-favorable timing of propagule release in barnacles and periwinkles

Abstract

Recent studies on the ecology of marine larvae suggest that retention near coastal areas and self-recruitment are probably much more common than previously thought. In light of this, the advective potential of pelagic stages can be partially determined by the timing of propagule release. We sampled the upper-shore levels of a subtropical coastline in southeastern Brazil to examine the temporal patterns of propagule release for the common barnacle Chthamalus bisinuatus and the periwinkle Nodilittorina lineolata. The release timing in both species was very consistent between sites a few kilometers apart. Barnacles released nauplii in a rhythmic pattern, mostly coinciding with neap tides, when the speed of tidal currents was lowest. There was no variation in propagule release in relation to diel or flood -ebb tidal cycles. Periwinkles released propagules in a very irregular pattern, which remarkably matched a time series of wave heights. Egg capsules were released during periods of rough seas, when onshore surface currents were expected to prevail. Eggs were released mostly during ebb tides, and there was no diel variation. Propagule release rhythms are usually viewed as a means to ensure fast offshore advection, thus avoiding presumed hazardous conditions for larvae. However, propagule release strategies in these upper-shore species would more likely contribute to the retention of offspring close to parental stocks. KEY WORDS: Reproductive timing · Propagule retention · Rocky shoresResale or republication not permitted without written consent of the publisher Mar Ecol Prog Ser 414: 155-165, 2010 gan 1995). In the case of intertidal brachyuran crabs, an extensive dataset suggests that hatching is timed with different environmental cycles, so that optimal release is expected to take place during spring tides, at nocturnal ebbing periods, ensuring a fast offshore advection to a habitat patch where predation risk is lower (Forward 1987, Morgan 1995. By this means, larvae may easily be transported off coastal retention zones. However, intertidal crabs are mobile animals which can undertake tidal excursions prior to hatching and larval development is relatively long, usually lasting from 3 to 10 wk (Hines 1986). In rocky shores, the most abundant organisms are sessile or sedentary, and their larvae develop relatively faster. Many of these animals also respond to environmental cues, which are far less predictable. For instance, phytoplankton blooms were shown to trigger spawning and larval release events in different marine invertebrates (Barnes 1962, Starr et al. 1990, and mechanical stimulation, which may simulate wave action, is frequently used to obtain gametes in mussels and polychaetes in the laboratory (e.g. Young 1945, Eckelbarger 1976. In such cases, ripe individuals must be capable of retaining their fully developed eggs until they perceive release-inducing stimuli. Because these environmental cues are highly stochastic, they are also very difficult to anticipate. Endogenous control in such species...

Reproductive cycles in tropical intertidal gastropods are timed around tidal amplitude cycles

“…However, it may be noteworthy that those studies based on observations of capsules and larvae released and collected in the field do not show such clear lunar or tidal amplitude patterns. For example, autocorrelation analysis of abundance of egg capsules of Nodilittorina lineolata collected along a Brazilian coast showed no relationship between capsule abundance and tidal height, but did show a close match to a time series of wave heights, with release occurring during rough seas (Bueno, Moser, Tocci, & Flores, ). This pattern was interpreted to support a pattern of propagule release that promotes onshore retention of capsules (Bueno et al., ).…”

“…For example, autocorrelation analysis of abundance of egg capsules of Nodilittorina lineolata collected along a Brazilian coast showed no relationship between capsule abundance and tidal height, but did show a close match to a time series of wave heights, with release occurring during rough seas (Bueno, Moser, Tocci, & Flores, ). This pattern was interpreted to support a pattern of propagule release that promotes onshore retention of capsules (Bueno et al., ). Egg capsules of Melarapha cincta and M. oliveri collected from tide pools also showed associations with rough weather, as well as high salinity, rather than any obvious lunar cycle (Pilkington, ).…”

“…A systematic survey of patterns of littorinid propagule release comparing release time in both the field and the laboratory would help determine whether intrinsic cycles tracking expected tidal height are modified by actual tidal height or wave exposure experienced in the field. Systematic comparisons could also assess the importance of the tidal height of the primary habitant occupied by each species (Berry, ), the magnitude of the tidal amplitudes, and/or the typical wave heights experienced by each species (Bueno et al., ).…”

Evidence for enhanced late-stage larval quality, not survival, through maternal carry-over effects in a space monopolizing barnacle

“…The species used in this study, the intertidal barnacle Chthamalus bisinuatus (Pilsbry), is the most common cirripede species along the subtropical Southeastern Atlantic, dominating the upper part of the eulittoral zone of rocky shores, where they frequently cover 80% or more of available substrates (Bueno et al, 2010). These filter feeding barnacles reproduce through cross fertilizationalthough some cases of self-fertilization have been reported for this genus (Barnes & Crisp, 1956;Anderson, 1994) -and the fertilized eggs are carried in the mantle cavity until the nauplius stage I is fully developed.…”

Chlorophyll-a and the Supply Side Ecology: Lessons from the Rocky Shores

“…Thus, it is common to observe peaks of larval release by rocky shore invertebrates synchronized with phytoplankton blooms (e.g., Refs. [28,29]). Some metabolites produced by phytoplankton are signs of favorable environmental conditions for the larval development, trigging the spawning activity of green sea urchins and blue mussels, for instance Ref.…”