I suppose it's as they say sometimes -- it's complicated! It depends somewhat on which aspect of it you're thinking about.
Both Purple Sea Urchins and Giant Green Anemones are broadcast spawners, with males and females releasing gametes into the water. The gametes need to find each other, so one possibility is that being in a pool might make that easier -- but if it's high tide, or if there's lots of wave action, the gametes will likely be swept out into the ocean (and away from the pool).
Both species also have planktonic larvae -- in the case of the urchins, the larval stage might last for ~6 weeks or longer -- making it likely they'll be swept out and away from the original pool with spawning adults. Giant Green Anemones have a shorter larval duration -- I'd need to look it up, but perhaps less than 1 week -- so although it's possible the larvae could remain closer, because of tides and wave action there are factors that would probably send them away from the original pool.
Another piece of this would include whether the planktonic larvae respond to cues from adults when they're searching for a place to settle (i.e., when they undergo metamorphosis and become a juvenile that will live on the rocks)...or just whether incoming larvae respond to the same cues as the adults that originally settled there. Either of those things could result in new larvae settling in the same pool, but those larvae/juveniles might not be related to the adults that are there (see above re: the effects of broadcast spawning, tides and wave action, and larval duration).
So you might see juveniles in the same pool, but it's hard to tell whether they're related to the adults or not (and in most cases with broadcast spawners, it's probably not likely). However, a high density of adults indicates good conditions for that species, as well as potential for reproduction, larval settlement, and juvenile survival.
Is that tidepool serving as a nursery for those urchins & anemones?
ReplyDeleteHi!
ReplyDeleteI suppose it's as they say sometimes -- it's complicated! It depends somewhat on which aspect of it you're thinking about.
Both Purple Sea Urchins and Giant Green Anemones are broadcast spawners, with males and females releasing gametes into the water. The gametes need to find each other, so one possibility is that being in a pool might make that easier -- but if it's high tide, or if there's lots of wave action, the gametes will likely be swept out into the ocean (and away from the pool).
Both species also have planktonic larvae -- in the case of the urchins, the larval stage might last for ~6 weeks or longer -- making it likely they'll be swept out and away from the original pool with spawning adults. Giant Green Anemones have a shorter larval duration -- I'd need to look it up, but perhaps less than 1 week -- so although it's possible the larvae could remain closer, because of tides and wave action there are factors that would probably send them away from the original pool.
Another piece of this would include whether the planktonic larvae respond to cues from adults when they're searching for a place to settle (i.e., when they undergo metamorphosis and become a juvenile that will live on the rocks)...or just whether incoming larvae respond to the same cues as the adults that originally settled there. Either of those things could result in new larvae settling in the same pool, but those larvae/juveniles might not be related to the adults that are there (see above re: the effects of broadcast spawning, tides and wave action, and larval duration).
So you might see juveniles in the same pool, but it's hard to tell whether they're related to the adults or not (and in most cases with broadcast spawners, it's probably not likely). However, a high density of adults indicates good conditions for that species, as well as potential for reproduction, larval settlement, and juvenile survival.
I hope this helps!
:) Jackie