Abundance and Distribution of Lobster Larvae (Homarus americanus) in Northumberland Strait

Abstract

A method is described for catching the planktonic larval stages of the lobster (Homarus ame,icanus Milne Edwards). Estimates are made of the abundance and distribution of each of the four stages in the surface waters of part of the Northumberland Strait (southern Gulf of St. Lawrence) fir the years lg4g-6l,with a more critical analysis for the year 196I-Both abundance and survival of the larvae lr.ry irorn year to year, although they do not appear to be related with measured hydrographical conditions. It is suggested that the distribution of stage I larvae reflects the iocation of the parent stock and that surface drift carries the developing larvae to possible areas of settlement.There is no conclusive relationship between the larvae and the subsequent stock, although a possible relationship between the abundance of stage I larvae and parent stock density is de' scribed and briefly discussed. lReceived for publication December 30' 1963' 661 J. Frsn. Rrs. Bo. CANAoe, 2l(4)' 1964. Printed in Canada.

Crude oil effects to developmental stages of the American lobster

“…This seawater concentr atio n i s within the range measured in surface waters beneath recently deposited oil slicks (Grose and Mattson, 1977;Law, 1978;Mackie et al, 1978) and because of the abundance of all larval stages in near surface waters (Scarratt, 1964; Lu nd and Stewart , 1970), would be encountered by l arva l lobsters immediately fo llowing a spi ll . Accumulation of hydrocarbons in a planktonic food so urce provides an alternative route of exposure to larval lobsters.…”

Vertical distribution and daily movements of larval lobsters Homarus americanus over Browns Bank, Nova Scotia

“…2). Sirmlarly, our results could also explain the greater proportion of stage IV larvae found in New England surface waters (Collings et al 1981, Bibb et al 1983, Grabe et al 1983, Lux et al 1983, Matthiessen & Scherer 1983 compared to that expected from estimates of natural mortality (Scarratt 1964, Harding et al 1982). Another explanation is that larvae could be advected away from the 'spawning' sites so that the developmental stages are segregated from each other by drift and dilution.…”

Vertical positioning and swimming performance of lobster larvae (Homarus gammarus) in an artificial water column at Helgoland, North Sea

“…However, the older larvae tend to hold their position near the bottom where current speeds are considerably lower and may thus be able to remain in the favoured habitat. In contrast, Scarratt (1964) suggested that surface drift carries the larvae of H. americanus from parent stock to possible areas of settlement. This may be seen as an advantage in a more homogeneous environment.…”

“…Templeman 1937;Harding et al 1987), whereas only few studies on larvae of H. gammarus exist (Nichols & Lawton 1978;Tully & Ó Céidigh 1987). Larvae of H. americanus of all stages were found in large numbers in the plankton (Templeman 1937;Scarratt 1964). In contrast, larvae of H. gammarus are generally rare in the plankton, and most commonly the first and the fourth larval stages were found (Dunn & Shelton 1983;Minchin 1984).…”