Use of larval supply in benthic ecology:testing correlations between larval supply and larval settlement

Conceptual models in manne benthic ecology have been reinforced with the use of larval recruitment as a key factor to predict fluctuations in the abundance and distnbution of sessile adult populations In turn, larval recruitment is determined uslng vanous indicators of planktonic larval abundance (larval supply) Based on plankton and settlement data collected over an entire settlement penod of the barnacle Sem~balanus balanoldes, we explore the vanability in the strength of the relationships between the abundance of newly settled individuals sampled dally at 3 shore levels and the daily larval abundance at 3 different depths over a 10 d study period The best correlation was obtained between the number of larvae collected near the bottom and the number of spat sampled in the low intertidal More than 75% of the vanability in the abundance of newly settled spat In the lower intertidal was explained by vanations in the larval abundance near the bottom Larval abundance integrated over the entire water column explained -50% of the vanability In low shore settlement, but failed to be significant All other comparisons showed a lack of correlations Our approach demonstrates that indicators of larval supply must be carefully and solidly documented to reflect the relationships between abundance of competent larvae settlement intensity and subsequently recruitment