Lobster larval transport in the southern Gulf of St. Lawrence

Abstract

A bio-physical semi-Langrangian model was developed to follow the drift and abundance of lobster larvae from hatching to settlement as post-larvae. The geographic domain encompasses Northumberland Strait and the areas surrounding Prince Edward Island in the southern Gulf of St. Lawrence. The model was run for ten larval seasons, 1983-87 and 1997-2001, representing two periods of egg production. The model was forced with tides, winds, heat fluxes, and marine and freshwater fluxes at open boundaries. Biological inputs were location, date, and density of larvae at hatching, development rates, a time window and a minimum bottom temperature required for successful settlement, and two scenarios of daily mortality. Net drift was west to east but stronger on the north than the south side of Prince Edward Island. The hatch was greater in the second 5-yr period, but the spatial patterns of settlement were similar. For both mortality scenarios, the same five of the 24 larval source areas were important in providing settlers. Horizontal shear of larval distribution indicates fishing communities were dependent on the hatch from fishing grounds of multiple upstream communities. Variation in daily and annual post-larval settlement was greatest north of Prince Edward Island. From the 24 source areas there was an eightfold range in the fraction of larvae surviving to settlement, with advection into deep water an important cause of mortality. Four to five possible fishery management areas were identified using multidimensional scaling to group sink areas having shared source areas. We hypothesize leaky discontinuity in connectivity between these groups.

The geography and bathymetry of American lobster benthic recruitment as measured by diver-based suction sampling and passive collectors

“…The significant correlation of youngof-year and older juveniles at the same sites, together with our longer-term time series at these locations and previous larval transport modelling , suggests spatial differences in recruitment are relatively consistent year to year, resulting in recruitment hot and cold spots. Advective processes influencing larval and postlarval transport could be responsible for consistent along-shore heterogeneity in settlement to coastal nurseries Xue et al 2008;Chassé & Miller 2010;Incze et al 2010). However, as has been shown for other benthic species (Burke 1986;Pearce & Figure 6.…”

Modelacion de la conectividad de las subpoblaciones de la langosta de Juan Fernandez (Jasus frontalis), a traves de un modelo biofisico

“…Este tipo de aproximación permite hacer inferencias sobre el nivel de homogeneización, conectividad y/o retención dentro de un sistema, producto de factores físicos y biológicos (Incze et al, 1999(Incze et al, , 2010Hinckley et al, 2001;Parada et al, 2003Parada et al, , 2008Parada et al, , 2010Grimm et al, 2006;Miller et al, 2006;Xue et al, 2008;Hinckley et al, 2009). Estos modelos hidrodinámicos acoplados a modelos biológicos ya han sido utilizados para estudiar la conectividad de varias poblaciones de crustáceos (Xue et al, 2008;Chassé & Miller, 2010;Incze et al, 2010;Parada et al, 2010) y han permitido establecer la estructura y dinámica espacio-temporal de las poblaciones. Este acoplamiento de modelos físico-biológicos constituye una herramienta esencial para abordar de forma robusta los complejos procesos que determinan la conectividad de las poblaciones en sistemas marinos.…”

Revisiting recent history: records of occurrence and expansion of the European green crab across Prince Edward Island, Atlantic Canada

“…Empty bins indicate sites and years in which no survey was conducted (e.g. Koutitonsky and Bougden 1991;Chassé and Miller 2010;Brickman 2014). Touring boat traffic, shellfish aquaculture transfers and fisheries are intense along both shorelines, so it is unlikely that these vectors could have resulted in the large difference in expansion between the north and south shores.…”