Aspects of Larval American Lobster (Homarus americanus) Ecology in St. Georges Bay, Nova Scotia

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Abstract
Lobster larvae first appeared in the neuston of St. Georges Bay, N.S., in 1978 on June 22 at a surface temperature of 12.5 °C. Abundances ranged from 0 to 243 × 103 larvae∙km−2 throughout the larval season with a seasonal average of 22.9 ± 37.9 × 103 larvae∙km−2 for the entire bay. Larval production in the bay equals the highest values reported in the literature for individual stations in nearby western Northumberland Strait. We derive the first survival estimate from larval stage 1 to recruits entering the fishery of 0.2–0.4%. On average 81.4, 14.1, and 4.5% of the larvae were caught within the upper 30-cm, 30- to 70-cm, and 70- to 110-cm levels beneath the sea surface, respectively. This daytime distribution of lobster larvae in the upper 110 cm is modified by cloud cover. The adult distribution in the bay and wind-driven surface drift are believed to be the two main causes of the observed large-scale horizontal patchiness. Lobster larvae have a significantly high probability of capture by our nets if patches of floating seaweed are encountered. A hypothesis is proposed that the observed small-scale patchiness of both larvae and weed is caused by Langmuir circulation.Key words: lobster larvae, Homarus americanus, ecology, Langmuir circulation, recruitment, survival, Nova Scotia

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