Elsevier

Journal of Sea Research

Volume 64, Issues 1–2, July–August 2010, Pages 34-44
Journal of Sea Research

Effect of nursery habitat degradation on flatfish population: Application to Solea solea in the Eastern Channel (Western Europe)

https://doi.org/10.1016/j.seares.2009.08.003Get rights and content

Abstract

Estuaries and coastal waters are essential nursery habitats for many marine species, and especially for flatfishes. Thus, investigating how anthropogenic disturbances affect the quality of these habitats is of major importance to understand their consequences on the population renewal of marine species.

The aim of the present study was to analyse the effects of estuarine habitat degradation on the population of the common sole in the Eastern Channel, a key species in the fish community and fisheries in this area. We especially focused on the drastic drop in the surface area and on the low water quality of the Seine estuary, the main river of the Eastern Channel.

A geographic Information System (GIS) was used to develop quantitative maps of sole nursery habitats in the Eastern Channel by using a habitat suitability model based on bathymetry and sediment structure. This approach indicated that juvenile densities are low in the Seine estuary with regards to other nursery sectors. Then, thanks to historical maps of the Seine estuary, habitat suitability maps were built for key dates in the modifications of this estuary since 1850. This backward predictive approach suggests that habitat loss in the Seine estuary has led to a 42% decrease of its nursery capacity. As the density of juvenile sole in the Seine estuary is low in comparison to other sectors, this represents only a 3% loss at the sole population scale, in the Eastern Channel. However, when we assumed that prior to anthropogenic disturbance the juvenile density in the Seine estuary might have been equivalent to the current density of adjacent sectors with higher quality, the loss in abundance could be nearly 23% (8–36%). Results suggest that the loss in habitat surface combined with habitat degradation has led to an important loss in the contribution of the Seine estuary nursery to the whole sole population in the Eastern Channel.

Introduction

Estuaries and coastal areas are essential fish habitat because they act as nursery grounds for various marine fish species (Able, 2005, Beck et al., 2001, Miller et al., 1984). Juvenile growth and survival are determined by both the capacity and quality of these nursery habitats (Gibson, 1994, Iles and Beverton, 2000, Rijnsdorp et al., 1992). The increase of human activities along rivers, estuaries and in coastal areas affects ecosystems, in particular by pollution and habitat destruction (Coleman et al., 2008, Diaz and Rosenberg, 2008, Halpern et al., 2008). Habitat degradation is one of the most serious threats for the recovery of fish stocks (Hall, 1998). Quantitative and qualitative factors related to anthropogenic disturbance (Meng et al., 2000, Phelan et al., 2000) influence the quality of coastal and estuarine nurseries and thus recruitment and renewal of populations (Burke et al., 1993, Cowan et al., 2000, Ferber, 2001, Johnson et al., 1998, Peterson et al., 2000, Scharf, 2000, Thrush et al., 2008).

The inshore waters of the Eastern Channel (ICES Division VIId; Fig. 1) support nursery areas for several commercially important species, especially the common sole (Solea solea, L.) (Riou et al., 2001). The Bay of Seine is the largest estuary in the Eastern Channel and is thereby a potentially important nursery ground. However, this sector is highly disturbed through channel dredging, constructions of dikes and harbour extensions, which have substancially reduced the estuary area and subsequently suitable juvenile fish habitats, such as shallow muddy areas (> 75% decrease; Lesueur, 1999). In addition, concentrations of organic chemical contaminants are high in this estuary, it being among the most contaminated in Europe (Gilliers et al., 2006), with episodes of oxygen depletion (Billen and Poulin, 1999). Thus, human disturbances have affected, perhaps reduced the nursery function of this estuary (Le Pape et al., 2007): its contribution to the renewal of flatfish stocks in the Eastern Channel is currently low (Riou et al., 2001) and fish growth performance and population density are significantly lower than in other nursery areas (Gilliers et al., 2006).

The present study aims to quantify the effects of human disturbance on sole nursery grounds in the Seine estuary and establish their consequences on the sole population of the Eastern Channel. A habitat suitability model, constructed for the recent period, was used in combination with historical habitat maps to provide backward projections of the potential juvenile sole densities. A two-step approach was used: 1) A quantitative map of sole nursery habitats in the Eastern Channel during recent times was first developed in a Geographic Information System (GIS). A database was built by collating trawl surveys undertaken throughout the coastal and estuarine parts of the Eastern Channel during the three last decades. A generalized linear model (GLM) was developed to identify key factors explaining variations of juvenile sole densities in various habitats, featured by different subregions, bathymetry and sediment structure. Using this GLM and a GIS, key sites for the early life-history stages of sole were identified. 2) Historical maps of the Seine estuary were used to construct habitat suitability maps for key dates in the modifications of this estuary since 1850. Combining the historical suitability maps and the GLM model of sole densities, the historical productions of the Seine estuarine nursery were calculated and related to its contribution to the sole population.

Section snippets

Beam trawl survey data

From 1974 to 2007, different beam trawl surveys focused on juvenile flatfish species have been undertaken throughout the Eastern Channel coastal zone (Fig. 1, Table 1). Riou et al. (2001) collated these survey data until 1998. Data used in the present study were for a large part identical to this database, with an upgrade with the surveys undertaken between 1999 and 2007 (UK surveys on the English coast, French surveys in the downstream of the Seine estuary and in the Bay of Somme). In 2006,

Distribution of YoY in the Eastern Channel at the present time

All factors except the “sediment” had a significant effect in the two sub-models (Table 4). The “Sediment” effect was not significant (p = 0.4) in the sub-model for positive densities (Table 4). This factor was then excluded from this sub-model.

When considering the effect of the different factors obtained from the delta model (Fig. 4), differences between sectors are markedly pronounced (Fig. 4a): on average, the highest YoY densities (Rye Bay) reached tenfold the smallest ones (South Downs). The

An approach based on several hypotheses: overview of possible bias

To model the effect of habitat degradation in the Seine estuary, a habitat suitability model based on scientific surveys undertaken during the past 30 years was coupled with a GIS that incorporated actual and historical maps. Several methodological points could be discussed and improved in future research.

Acknowledgements

This project was supported by the French National Research Agency (ANR, Project SoleBeMol-Pop, ANR Vulnérabilité, Milieux et climat. Special thanks to Franck Coppin (Ifremer, Boulogne sur Mer, France) and Marie Laure Cochard (Ifremer, Port en Bessin, France) for their help on collection of trawl survey data, Mario Lepage and his colleagues (Cemagref, Bordeaux, France) for their help in gathering trawl data of the Water Framework Directive, Michel Bellouis and Benoit Loubrieu (Ifremer, Plouzané,

References (81)

  • B. Kuipers

    On the efficiency of a two-metre beam trawl for juvenile plaice (Pleuronectes platessa)

    Netherlands Journal of Sea Research

    (1975)
  • O. Le Pape et al.

    Quantitative description of habitat suitability for the juvenile common sole (Solea solea, L.) in the Bay of Biscay (France) and the contribution of different habitats to the adult population

    Journal of Sea Research

    (2003)
  • O. Le Pape et al.

    Quality of coastal and estuarine essential fish habitat: estimations based on the size of juvenile common sole (Solea solea L.)

    Estuarine, Coastal and Shelf Science

    (2003)
  • O. Le Pape et al.

    Relationship between interannual variations of the river plume and the extent of nursery grounds for the common sole (Solea solea, L.) in Vilaine Bay. Effects on recruitment variability

    Journal of Sea Research

    (2003)
  • D. Nicolas et al.

    Relationship between benthic macrofauna and habitat suitability for juvenile common sole (Solea solea, L.) in the Vilaine estuary (Bay of Biscay, France) nursery ground

    Estuarine, Coastal and Shelf Science

    (2007)
  • B.A. Phelan et al.

    Estuarine and habitat related differences in growth rates of young of the year winter flounder (Pseudopleuronectes americanus) and tautog (Tautoga onitis) in three northeastern US estuaries

    Journal of Experimental Marine Biology and Ecology

    (2000)
  • L. Pihl et al.

    Importance of exposure and habitat structure for the population density of 0-group plaice, Pleuronectes platessa L., in coastal nursery areas

    Netherlands Journal of Sea Research

    (1992)
  • L. Pihl et al.

    Shift in assemblage structure due to loss of seagrass Zostera marina habitat sin Sweden

    Estuarine, Coastal and Shelf Science

    (2006)
  • A.D. Rijnsdorp et al.

    Recruitment of sole stocks, Solea solea (L.), in the northeast atlantic

    Netherlands Journal of Sea Research

    (1992)
  • P. Riou et al.

    Relative contributions of different sole and plaice nurseries to the adult population in the Eastern Channel: application of a combined method using generalized linear models and a geographic information system

    Aquatic Living Resources

    (2001)
  • S.I. Rogers

    Environmental factors affecting the distribution of sole (Solea solea (L.)) within a nursery area

    Netherlands Journal of Sea Research

    (1992)
  • E.L. Shimps et al.

    Hypoxia tolerance in two juvenile estuary-dependent fishes

    Journal of Experimental Marine Biology and Ecology

    (2005)
  • C. Vinagre et al.

    Habitat suitability index models for juvenile soles, Solea solea & S. senegalensis, in the Tagus estuary: defining variables for species management

    Fisheries Research

    (2006)
  • C. Vinagre et al.

    Small-scale distribution of Solea solea and Solea senegalensis juveniles in the Tagus estuary (Portugal). Estuarine

    Coastal and Shelf Science

    (2009)
  • K.W. Able

    A re-examination of fish estuarine dependence: evidence for connectivity between estuarine and ocean habitats. Estuarine

    Coastal and Shelf Science

    (2005)
  • K.W. Able et al.

    Habitat quality for shallow water fishes in an urban estuary: the effects of man-made structures on growth

    Marine Ecology Progress Series

    (1999)
  • R.L. Allen et al.

    Distribution and microhabitat use by flatfishes in a Louisiana estuary

    Environmental Biology of Fishes

    (1997)
  • R. Amara et al.

    Growth and condition indices in juvenile sole Solea solea measured to assess the quality of essential fish habitat

    Marine Ecology Progress Series

    (2007)
  • Anonymous

    The final resolution of the symposium on the classification of brackish waters. Venice 8–14th April 1958

    Archivio di Oceanografia e Limnologia

    (1959)
  • Anonymous

    Report of the ad hoc working group on the 1984 and 1985 sole (Solea solea L.) egg surveys

  • Anonymous
  • Avoine, J., L'estuaire de la Seine: sédiments et dynamique sédimentaire. PhD thesis. Univ. Caen, (1981), 236...
  • J. Avoine et al.

    Evolution morphologique et couverture sédimentaire de l'estuaire de la Seine: actualisation et fluctuations

  • M.W. Beck et al.

    The role of nearshore ecosystems as fish and shellfish nurseries

    BioScience

    (2001)
  • G. Billen et al.

    L'oxygène. Un témoin du fonctionnement microbiologique

  • J. Burke et al.

    Morphological indices and otolith microstructure of Atlantic croaker, Micropogonias undalatus, as indicators of habitat quality along an estuarine pollution gradient

    Environmental Biology of Fishes

    (1993)
  • J.M. Coleman et al.

    Wetland loss in world deltas

    Journal of Coastal Research

    (2008)
  • M.J. Costa et al.

    Changes in the Tagus nursery function for commercial fish species: some perspective for management

    Aquatic Ecology

    (1999)
  • J.H. Cowan et al.

    Is density dependent growth in young of the year fishes a question of critical weight?

    Reviews in Fish Biology and Fisheries

    (2000)
  • C.P. Dahlgren et al.

    Marine nurseries and effective juvenile habitats: concepts and applications

    Marine Ecology Progress Series

    (2006)
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