The behavior of the larval and adolescent stages of the American lobster (Homarus americanus)

Abstract

261 3. Mechanics of body-orientation 263 A. The effect of direct lighting and shading B. The effect of screens and backgrounds.. 289 IX. LIST OF REFERENCES..

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

“…In our experiments, the newly hatched lobster larvae reacted immediately to light Á irrespective of the direction Á even if it came from the bottom and responded with a downward vertical swimming speed of about 4Á5 cm s (1 (including the sinking rate of 1.7 cm s (1 ). The same positive phototatic reaction was observed in the first larval stage of the American lobster, Homarus americanus (Hadley 1908). Furthermore, other crustacean larvae respond equally in their first Zoea stage, e.g.…”

“…Additionally, the low sinking rate of Zoea I facilitates their positive phototactic behaviour before they tend to swim to the deeper layers in the later stages. Moreover, Hadley (1908) found that phototactic responses of larvae of H. americanus changed both within and between each stage. He reported that larvae in early second and third stages are negatively phototactic, but again respond positively to light shortly (Âone day) before moulting.…”

“…The locomotion ability of larvae changes during their larval development (Ennis 1995) and the major swimming appendages of the pelagic larvae are the exopodite branches of the third maxillipeds, the chelipeds and the four pairs of pereipods (Neil et al 1976). By beating of the exopodites, the larvae carry forward, backwards or upwards; when their motion ceases, however, the larvae sink towards the bottom (Hadley 1908). The distribution of larvae is controlled by environmental factors such as currents systems, pressure, the lightÁ dark regime, temperature, predators, and food abundance; and by behavioural components such as swimming ability and the active orientation to these environmental cues (Ennis 1983;Hudon & Fradette 1993).…”

“…In previous experiments, larvae oriented through perception of hydrostatic pressure and showed specific phototactic (Ennis 1973) and rheotactic behaviour (Ennis 1986). Hadley (1908) described phototactic responses of larvae of H. americanus and found that larvae changed their phototactic behaviour both within and between each stage. Mileikovsky (1973) summarized the larval swimming speed of bottom invertebrates with different methods employed.…”

Biogeographic, ontogenetic, and environmental variability in larval behaviour of American lobster Homarus americanus

“…Development of larvae, and thus pelagic larval duration, is temperature dependant (Mackenzie 1988, Quinn et al 2013, lasting several weeks to 2 months across the species range depending on local conditions. Because planktonic stages are extremely capable swimmers (Hadley 1908, Templeman 1936, Ennis 1986, with swim speeds estimated at ~20 cm s −1 during the post-larval stage (Cobb et al 1989), they span other invertebrates and fishes in terms of potential active contributions to dispersal. This behavioural capacity, coupled with an expected interaction between temperature and behaviour (i.e.…”