Does global warming impact on migration patterns and recruitment of Allis shad (Alosa alosa L.) young of the year in the Loire River, France?

Abstract

The hydrological and thermal changes in the Loire River were investigated to test the influence of climatic changes on a short freshwater stage anadromous fish species, Allis shad, for the 1995-2004 period. The mean water temperatures during the adult migration and juvenile growth phases showed significant increase, and mean water flow during these two phases decreased significantly. The period below the threshold of 18°C shortened, and the period between 18°C and the maximum lengthened, while the temperature amounts (number of degree-days) received by aquatic organisms between 18 and 24°C showed an increase. The pattern of young-of-the-year downstream migration was modified. The first day when the juvenile catches reached 5% occurred 17 days earlier at the end of the 1995-2004 period than at the beginning. The first day when the juvenile catches reached 50% was related to the 18°C threshold (reproductive threshold) and the temperature amounts accumulated between the 18 and 20°C thresholds. The year-on-year levels of young-of-theyear abundance showed wide variations, which were not explained by environmental parameters, probably because of the long distance between the study site and the spawning grounds.

Influence of landscape and hydrological factors on stream–air temperature relationships at regional scale

“…There is therefore a growing interest in understanding the spatio-temporal variability of river thermal regime given the likely effects of climate change (increase of both the Ta and the evapotranspiration, shift in river flow regimes and of groundwater inflows, etc. The goal is to develop opportunities for mitigation and adaptive management of river systems (Boisneau, Moatar, Bodin, & Boisneau, 2008;Hrachowitz, Soulsby, Imholt, Malcolm, & Tetzlaff, 2010;Jackson, Malcolm, & Hannah, 2015;Kurylyk, MacQuarrie, Linnansaari, Cunjak, & Curry, 2015). The goal is to develop opportunities for mitigation and adaptive management of river systems (Boisneau, Moatar, Bodin, & Boisneau, 2008;Hrachowitz, Soulsby, Imholt, Malcolm, & Tetzlaff, 2010;Jackson, Malcolm, & Hannah, 2015;Kurylyk, MacQuarrie, Linnansaari, Cunjak, & Curry, 2015).…”

“…; Webb et al, 2008;Moatar et al, 2010). The goal is to develop opportunities for mitigation and adaptive management of river systems (Boisneau, Moatar, Bodin, & Boisneau, 2008;Hrachowitz, Soulsby, Imholt, Malcolm, & Tetzlaff, 2010;Jackson, Malcolm, & Hannah, 2015;Kurylyk, MacQuarrie, Linnansaari, Cunjak, & Curry, 2015).…”

Thermal tolerance of allis shad (Alosa alosa) embryos and larvae: Modeling and potential applications

“…In the specific case of allis shad, temperature is one of the main environmental driver of the species distribution (Béguer et al 2007) and regulates several phases in life history, such as adult migration (Rochard 2001), spawning (Cassou-Leins et al 2000), egg development (Taverny et al 2000b) and juvenile migration (Boisneau et al 2008). However, there have been no published studies on the survival and upper tolerance limits of the allis shad.…”

A multimodel comparison for assessing water temperatures under changing climate conditions via the equilibrium temperature concept: case study of the Middle Loire River, France

“…Not only does this parameter influence the O 2 content of water (Sand-Jensen and Pedersen, 2005), but it also affects the consumption rates of nutrients by organisms, potentially leading to alterations in water quality during instances of increasing temperatures. Warming also modifies the distributions and dynamics of aquatic species across hydrographic networks (Eaton and Scheller, 1996;Boisneau et al, 2008). For example, recent climate warming enhances thermal stress for fish populations and tends to restrict their summer habitats drastically (Headrick and Carline, 1993).…”