Spatial distribution of Greenland halibut Reinhardtius hippoglossoides in relation to abundance and hypoxia in the estuary and Gulf of St. Lawrence

Abstract

Annual bottom‐trawl surveys (1990–2010) were used to examine associations between environmental conditions, spatial distribution, and size‐specific abundance of Greenland halibut Reinhardtius hippoglossoides in the estuary and Gulf of St. Lawrence (EGSL), and to test the influence of hypoxic conditions on habitat selection. Size classes representing juvenile, immature and adult fish were used for the analyses. The highest concentrations of fish were found in the St. Lawrence estuary at both high and low levels of stock abundance. The areas occupied by 50, 75, and 95% of juvenile fish expanded with higher population abundance. However, contrary to our predictions, densities in marginal habitats did not increase at a higher rate than in optimal habitats. Fish longer than 32 cm were distributed over a broader area than juvenile fish. Their abundance explained a limited proportion of the variability in spatial distribution. The spatial dynamics of Greenland halibut in the EGSL is best described by a proportional density model where the rate of increase in local density is associated with population abundance. Habitats selected by Greenland halibut were characterized by low dissolved oxygen (DO) levels. The strong association between high fish densities and low DO concentrations indicates a high tolerance of Greenland halibut to hypoxia. It also indicates that negative effects, if present, could be compensated by other factors such as food availability and/or refuge from predation. The results of this study also clearly define the St. Lawrence estuary as the major nursery area for the EGSL population.

Putting Temperature and Oxygen Thresholds of Marine Animals in Context of Environmental Change: A Regional Perspective for the Scotian Shelf and Gulf of St. Lawrence

“…Note that the AR12 Northern shrimp experiments were conducted at two temperatures (6.7 and 9.5 C), with a decreased development rate observed only at the lower temperature. References are coded as follows: AR12 = [80]; BE06 = [81]; BE11 = [82]; CH13 = [12]; FO03 = [83]; FO06 = [84] (FO06 did not maintain constant pH: here, time mean pH values are plotted); FR13 = [85]; KE12 = [86]; ME09 = [87]; MO11 = [88]; MU11 = [29]; RI09 = [89]; YO13 = [90]. GSL = Gulf of St. Lawrence; SLE = St. Lawrence Estuary.…”

Quantifying the influence of geography and environment on the northeast Atlantic mackerel spawning distribution

“…While geography is often found to control spawning habitat in demersal species, e.g., Greenland halibut (Ait Youcef, Lambert, & Audet, ), walleye pollock (Bacheler et al., ), plaice (Loots et al., ), and whiting (Loots et al., ), the habitat of pelagic species is more often thought to be structured by physical or hydrographic features, e.g., Atlantic bluefin tuna (Reglero et al., ), sardine and anchovy (Giannoulaki et al., ; Planque et al., ). Reglero et al.…”

Impact of hypoxia on the metabolism of Greenland halibut (Reinhardtius hippoglossoides)

“…Greenland halibut, Reinhardtius hippoglossoides (Walbaum), is an important commercial species in the North Atlantic, and for the last 20 years it has been the most important commercial demersal fish in the Estuary and Gulf of St. Lawrence (EGSL), accounting for 58% of fish catches in terms of biomass (DFO 2011). Recently, Ait Youcef et al (2013) have shown that the St. Lawrence estuary is the major nursery area for the EGSL population and that habitats selected by Greenland halibut are characterized by low dissolved oxygen (DO) levels. The strong association between higher fish densities and the low DO concentrations suggest a high tolerance of Greenland halibut to hypoxia.…”