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Cited by 184Marine and fisheries researchFish Ecology and Management StudiesOceanographic and Atmospheric Processes

Modelling potential spawning habitat of sardine ( Sardina pilchardus ) and anchovy ( Engraulis encrasicolus ) in the Bay of Biscay

Open access
PLANQUE, BENJAMIN, BELLIER, EDWIGE, LAZURE, PASCAL·2007·Fisheries Oceanography
DOI 10.1111/j.1365-2419.2006.00411.x
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Abstract

Abstract Large amplitude variations in recruitment of small pelagic fish result from interactions between a fluctuating environment and population dynamics processes such as spawning. The spatial extent and location of spawning, which is critical to the fate of eggs and larvae, can vary strongly from year to year, as a result of changing population structure and environmental conditions. Spawning habitat can be divided into ‘potential spawning habitat’, defined as habitat where the hydrographic conditions are suitable for spawning, ‘realized spawning habitat’, defined as habitat where spawning actually occurs, and ‘successful spawning habitat’, defined as habitat from where successful recruitment has resulted. Using biological data collected during the period 2000–2004, as well as hydrographic data, we investigate the role of environmental parameters in controlling the potential spawning habitat of anchovy and sardine in the Bay of Biscay. Anchovy potential spawning habitat appears to be primarily related to bottom temperature followed by surface temperature and mixed‐layer depth, whilst surface and bottom salinity appear to play a lesser role. The possible influence of hydrographic factors on the spawning habitat of sardine seems less clear than for anchovy. Modelled relationships between anchovy and sardine spawning are used to predict potential spawning habitat from hydrodynamical simulations. The results show that the seasonal patterns in spawning are well reproduced by the model, indicating that hydrographic changes may explain a large fraction of spawning spatial dynamics. Such models may prove useful in the context of forecasting potential impacts of future environmental changes on sardine and anchovy reproductive strategy in the north‐east Atlantic.

AI snapshot

Written from the paper’s full text.

TL;DR

Using 2000–2004 PELGAS egg and hydrographic data, this study models potential spawning habitat of sardine and anchovy in the Bay of Biscay with generalised additive models. Anchovy habitat is best predicted by bottom temperature, surface temperature and mixed-layer depth, while sardine relationships are weaker and less clear.

Key findings

  • Anchovy potential spawning habitat was best explained by bottom temperature (35% deviance, GCV 0.508), followed by surface temperature and mixed-layer depth; surface and bottom salinity played lesser roles. Anchovy spawning occurred mostly at 14.5–19°C surface and 12–15°C bottom, with a lower bottom-temperature limit near 12°C and an optimal surface temperature around 17°C; eggs were preferentially in low surface salinity (<34), shallow mixed layers, and either weakly stratified (PED <30 J) or highly stratified (PED >110 J) waters.
  • Sardine relationships were less clear: all hydrographic predictors had similar deviance and GCV scores, and deviance explained was generally lower than for anchovy. Sardine showed a surface thermal preferendum around 12.5–15°C, a bimodal bottom-temperature response with a first mode near 11.75°C and positive values beyond 12.5°C, and bimodal surface salinity effects (<33.5 and >35.25); eggs occurred across mixing depths, with higher presence for deep or very shallow mixed layers and decreasing presence as stratification increased.
  • Multiple-predictor GAMs for anchovy improved up to 5 predictors but gained little beyond a 3-predictor model (bottom temperature, surface salinity, surface temperature); the best sardine model included all six hydrographic predictors. Hydrodynamical simulations for 1999 reproduced seasonal spawning patterns, with anchovy potential habitat absent in late winter and extending in spring, while sardine habitat covered larger, more patchy areas and extended northward.
  • Adult biomass was almost unrelated to mean egg-presence probability for anchovy (r² = 0.02, n = 5); sardine showed a positive relationship (r² = 0.6, n = 4) but it depended on one year (2001), so the study could not conclude that year-to-year realised spawning habitat was directly linked to adult biomass.

Methods

  • Five spring PELGAS cruises (2000–2004) sampled the Bay of Biscay continental shelf. Eggs were collected with a CUFES pumping seawater at 3 m depth at about 500 L/min, with 20-minute samples corresponding to about 10 m³ filtered seawater over about 3 nautical miles; sardine and anchovy eggs were identified, counted, standardised to eggs per 10 m³, and converted to presence/absence. Hydrographic profiles were taken at fixed stations at night with CTD; six parameters were derived: surface and bottom temperature, surface and bottom salinity, potential energy deficit, and mixed-layer depth; profiles deeper than 100 m were truncated to the first 100 m.
  • Egg presence and hydrographic parameters were interpolated on the same 1/8° grid by ordinary point kriging. Generalised additive models (GAMs) in R’s mgcv were fitted first with single predictors, ranked by deviance explained, GCV score, and confidence regions, then with multiple predictors (1–6) selected by GCV and deviance. Potential habitat was predicted from MARS3D hydrodynamical simulations (5 km horizontal resolution, 10 vertical sigma layers) for 1999, restricted to areas shallower than 1000 m, with no prediction where modelled predictors fell outside observed ranges.

Limitations

  • Stated: the field cruises were centred on spawning areas and timing, so they included only a fraction of non-spawning sites and a limited range of hydrographic situations; the description is limited to subsurface (3 m) egg presence, and vertical egg distribution was not modelled; simulations depend heavily on the hydrodynamical model’s realism; predicting potential spawning habitat is not predicting realised spawning or spawning success; and the biomass analysis could not establish a year-to-year link to realised spawning habitat for the period studied.
  • Evident from the text: individual GAM p-values could not be used because of strong spatial autocorrelation and unknown true degrees of freedom; the study covers only five years (2000–2004) and one simulation year (1999); and sardine relationships were weak and less clear, with all hydrographic predictors performing similarly and lower deviance explained than for anchovy.

Model-written summary. Check it against the paper before relying on it.

Integrity signals

Registry

Crossref · 10.1111/j.1365-2419.2006.00411.x

Cites

49 of 49 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Claims the paper makes

2 of 29 cited sources checked · 2 supported · 0 flagged

  • Premisecitation

    The cold pool structure is present from southern Brittany down to the latitude of the Gironde estuary, centred over the 100-m depth zone.

    “This structure is known to be present from southern Brittany, down to the latitude of the Gironde estuary, centred over the 100-m depth zone.”
    Quote in the paperNot a substantial claim1 of 2 sources checked
    • cites Vincent andKurc, 1969

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

    • cites Puillat et al., 2004 source
  • Findingnone given

    The influence of hydrographic factors on sardine spawning habitat is less clear than for anchovy.

    “The possible influence of hydrographic factors on the spawning habitat of sardine seems less clear than for anchovy.”
    Quote in the paperNot a substantial claim
  • Findingown data

    The seasonal patterns in spawning are well reproduced by the model.

    “The results show that the seasonal patterns in spawning are well reproduced by the model,”
    Quote in the paperSubstantial claim
    • Rests on an assumption: GAM relationships fitted on 2000-2004 egg presence and hydrographic data can be applied to hydrodynamical simulations to predict potential spawning habitat.
  • Findingown data

    Anchovy potential spawning habitat is primarily related to bottom temperature, followed by surface temperature and mixed-layer depth, while surface and bottom salinity play a lesser role.

    “Anchovy potential spawning habitat appears to be primarily related to bottom temperature followed by surface temperature and mixed-layer depth, whilst surface and bottom salinity appear to play a lesser role.”
    Quote in the paperSubstantial claim
  • Findingown data

    Anchovy egg presence shows a preference for either weakly stratified (PED < 30 J) or highly stratified waters (PED > 110 J).

    “This is combined with a preference for either weakly stratified (PED < 30 J) or highly stratified waters (PED > 110 J, Fig. 5f 10 left).”
    Quote in the paperSubstantial claim
  • May combine two claims. 32
  • Classified as probably not a substantial claim. 8

  • May combine two claims.

    Premisecitation

    Previous studies suggest that the vertical distribution of anchovy and sardine eggs is variable but in most cases a fraction of the eggs is always present in the first 5 meters.

    “Previous studies (Coombs et al., 1985, Olivar et al., 2001, Boyra 20 et al., 2003, Coombs et al., 2003) suggest that the vertical distribution of anchovy and sardine eggs is variable but in most cases a fraction of the eggs is always present in the first 5 meters”
    Quote in the paperSubstantial claim1 of 3 sources checked
    • cites Coombs et al., 1985 source
    • cites Olivar et al., 2001 source
    • cites Boyra et al., 2003 source

  • May combine two claims.

    Findingown data

    The influence of bottom salinity on anchovy egg presence is less obvious, although there is a decline in the GAM function with increasing salinity.

    “The influence of bottom salinity is less obvious although there is a decline in the GAM function with 30 increasing salinity (Fig. 5b left).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingnone given

    By early spring, the potential spawning habitat has extended over a broader area but preserves a similar geographical structure.

    “By early spring the potential spawning habitat has extended over a broader area but preserve a similar geographical structure.”
    Quote in the paperNot a substantial claim
    • The authors state this as an assumption: If eggs are present in the water column, they will be found at 3 m depth where the CUFES operates; the presence/absence index used in the study can be considered a good proxy for presence or absence of eggs in the water column.
    • Rests on an assumption: The hydrodynamical model can realistically mimic hydrographic conditions.

  • May combine two claims.

    Findingnone given

    In late winter, most of the coast along northern Spain appears favourable for spawning, as well as the southern part of the Bay of Biscay up to 45N, excluding a narrow coastal strip.

    “In late winter, most of the coast along northern Spain 5 appears favourable for spawning, as well as the southern part of the Bay of Biscay up to 45N, excluding a narrow coastal strip.”
    Quote in the paperSubstantial claim
    • The authors state this as an assumption: If eggs are present in the water column, they will be found at 3 m depth where the CUFES operates; the presence/absence index used in the study can be considered a good proxy for presence or absence of eggs in the water column.
    • Rests on an assumption: The hydrodynamical model can realistically mimic hydrographic conditions.

  • May combine two claims.

    Findingnone given

    The six hydrographic parameters chosen provide complementary information and are not strongly correlated with each other.

    “The six hydrographic parameters chosen provide complementary information and although they can be well structured in space (spatial autocorrelation) they are not strongly correlated with each other.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    For anchovy, bottom temperature is the predictor that best explains egg presence, with the highest deviance (35%) and lowest GCV score (0.508).

    “For anchovy, the predictor that can best explain egg presence is bottom temperature, with the highest deviance (35%) and lowest GCV score (0.508).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    For sardine, there is a regular increase in model quality as the number of predictors increases, and the best model includes all hydrographic predictors.

    “For sardine, there is a regular increase in model quality (both in terms of GCV and deviance) as the number of predictors increases, and the best model includes all hydrographic predictors.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    For sardine bottom temperature, the response is bimodal with a first mode around 11.75°C, and positive coefficients beyond 12.5°C.

    “For bottom temperature the response is bimodal with a first mode around 25 11.75°C, and positive coefficients values beyond 12.5°C.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Sardine eggs are found throughout the range of mixing depths with higher presence probabilities for either deep or very shallow mixed layers.

    “and eggs found throughout the range of mixing depths with 15 higher presence probabilities for either deep or very shallow mixed layers (Fig. 5e right).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Anchovy spawning is related to mixing depth, with greater egg presence in shallow mixed layer conditions.

    “Anchovy spawning is related to mixing depth, with greater egg presence in shallow mixed layer conditions (Fig. 5e left).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingnone given

    The modelled potential spawning habitat of sardine generally covers larger areas and is more patchy than that of anchovy.

    “The modelled potential spawning habitat of sardine generally covers larger areas and is more patchy than that of anchovy.”
    Quote in the paperNot a substantial claim
    • The authors state this as an assumption: If eggs are present in the water column, they will be found at 3 m depth where the CUFES operates; the presence/absence index used in the study can be considered a good proxy for presence or absence of eggs in the water column.
    • Rests on an assumption: The hydrodynamical model can realistically mimic hydrographic conditions.

  • May combine two claims.

    Findingreasoning

    Along the coast north of the Gironde estuary, hydrographic conditions are outside the range of the GAMs, so no potential spawning habitat is predicted for this region.

    “Along the coast to the north of the Gironde estuary, the hydrographic conditions are not within the range of the GAMs, so there is no prediction of the potential spawning habitat for this region.”
    Quote in the paperNot a substantial claim
    • The authors state this as an assumption: If eggs are present in the water column, they will be found at 3 m depth where the CUFES operates; the presence/absence index used in the study can be considered a good proxy for presence or absence of eggs in the water column.
    • Rests on an assumption: The hydrodynamical model can realistically mimic hydrographic conditions.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingreasoning

    The five cruises took place in contrasted hydrographic situations as a result of changes in individual cruise timing and meteorological conditions.

    “In summary, the five cruises have taken place in contrasted hydrographic situations as a result of changes in individual cruise timing and meteorological conditions (e.g.high precipitation in 2001, strong solar heating in 2003).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingnone given

    By late May, potential spawning habitat has restricted towards shallower waters, but also along the shelf break.

    “By late May, 10 potential spawning habitat has restricted towards shallower waters, but also along the shelf break.”
    Quote in the paperSubstantial claim
    • The authors state this as an assumption: If eggs are present in the water column, they will be found at 3 m depth where the CUFES operates; the presence/absence index used in the study can be considered a good proxy for presence or absence of eggs in the water column.
    • Rests on an assumption: The hydrodynamical model can realistically mimic hydrographic conditions.

  • May combine two claims.

    Findingown data

    For sardine, there is a positive relationship between observed biomass and mean probability of egg presence (r2=0.6, n=4), but it results from one year of observation only, in 2001, when estimated biomass and mean probability of egg presence were both low.

    “For sardine there is a positive relationship (r 2 =0.6, n=4) but it results from one year of observation only, in 2001, when the estimated biomass was low and the mean probability of egg 10 presence was also low.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: Adult fish biomass can potentially influence the spatial extent of spawning.

  • May combine two claims.

    Findingown data

    For anchovy, model quality increases up to 5 predictors, although little is gained beyond the 3-predictor model which includes bottom temperature, surface salinity and surface temperature.

    “For anchovy, the quality of the models increases up to 5 predictors, although 5 little is gained beyond the 3-predictors model which includes bottom temperature, surface salinity and surface temperature.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Bottom temperature appears to be the best predictor for anchovy potential spawning habitat, followed by surface temperature and mixed-layer depth, whilst surface and bottom salinity appear to play a lesser role.

    “Surprisingly, bottom temperature appears to be the best predictor for anchovy potential spawning habitat, followed by surface temperature and mixed-layer depth, whilst surface and bottom salinity appear to play a lesser role (Tables 1 and 2).”
    • Also stated in: § DISCUSSION · plain
      “The moderate role of salinity in the Bay of Biscay is consistent with the findings of Reid (1966) at the scale of the global ocean.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Reid (1966)

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

    • The authors state this as an assumption: If eggs are present in the water column, they will be found at 3 m depth where the CUFES operates; the presence/absence index used in the study can be considered a good proxy for presence or absence of eggs in the water column.
    • Rests on an assumption: The hydrodynamical model can realistically mimic hydrographic conditions.

  • May combine two claims.

    Findingown data

    In late May, hydrographic conditions appear favourable over a wide area south of 46°N and more restricted towards the coast in the north.

    “In late May the hydrographic conditions appear favourable over a wide area south of 46°N and more restricted towards the coast in the north.”
    Quote in the paperNot a substantial claim
    • The authors state this as an assumption: If eggs are present in the water column, they will be found at 3 m depth where the CUFES operates; the presence/absence index used in the study can be considered a good proxy for presence or absence of eggs in the water column.
    • Rests on an assumption: The hydrodynamical model can realistically mimic hydrographic conditions.

  • May combine two claims.

    Findingown data

    At the end of April, the southern part of the Bay of Biscay appears less favourable for spawning, while north of the Gironde the potential habitat extends further towards the middle of the shelf.

    “At the end of April, the southern part of the Bay seems less favourable for spawning whilst to the north of the Gironde the potential habitat extends further towards the middle of the shelf.”
    Quote in the paperNot a substantial claim
    • The authors state this as an assumption: If eggs are present in the water column, they will be found at 3 m depth where the CUFES operates; the presence/absence index used in the study can be considered a good proxy for presence or absence of eggs in the water column.
    • Rests on an assumption: The hydrodynamical model can realistically mimic hydrographic conditions.

  • May combine two claims.

    Findingown data

    Aside from temperature effects, high egg abundance seems to prevail in either coastal well-mixed areas (shallow mixed-layer and low stratification energy) or highly stratified river plumes (shallow mixed-layer depth, high stratification and low surface salinity).

    “Aside from temperature effects, high egg abundance seems to prevail in either coastal well mixed areas (i.e.shallow mixed-layer and low stratification energy) or highly stratified river plumes (i.e.shallow mixed-layer depth, high stratification and 5 low surface salinity, Fig. 5).”
    Quote in the paperSubstantial claim
    • The authors state this as an assumption: If eggs are present in the water column, they will be found at 3 m depth where the CUFES operates; the presence/absence index used in the study can be considered a good proxy for presence or absence of eggs in the water column.
    • Rests on an assumption: The hydrodynamical model can realistically mimic hydrographic conditions.

  • May combine two claims.

    Findingnone given

    The late spawning at the shelf break north of 45°N is not well reproduced, although there are areas with high probability of egg presence but with very restricted spatial extension.

    “The late spawning at the shelf break north of 45°N is not well reproduced, although there are areas with high probability of egg presence but with very restricted spatial extension.”
    Quote in the paperNot a substantial claim
    • The authors state this as an assumption: If eggs are present in the water column, they will be found at 3 m depth where the CUFES operates; the presence/absence index used in the study can be considered a good proxy for presence or absence of eggs in the water column.
    • Rests on an assumption: The hydrodynamical model can realistically mimic hydrographic conditions.

  • May combine two claims.

    Findingcitation

    The modelled succession of spatial patterns for anchovy potential spawning habitat in 1999 is in agreement with field observations, with early spawning along the coast in the southern part of the Bay, followed by increasing spawning off the Gironde estuary and a gradual displacement towards northern coastal latitudes to the south of Brittany.

    “The modelled succession of spatial patterns for anchovy potential spawning habitat in 1999 is in agreement with field observations, as describe in Motos et al. (1996), with early spawning taking place along the coast in the southern part of the Bay, followed by increasing spawning off the Gironde estuary and a gradual displacement towards northern coastal latitudes to the South of Brittany.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Motos et al. (1996)
    • The authors state this as an assumption: If eggs are present in the water column, they will be found at 3 m depth where the CUFES operates; the presence/absence index used in the study can be considered a good proxy for presence or absence of eggs in the water column.
    • Rests on an assumption: The hydrodynamical model can realistically mimic hydrographic conditions.

  • May combine two claims.

    Findingown data

    Sardine appears to have a greater tolerance than anchovy for low bottom temperature, although it also appears to avoid cold pool waters.

    “Sardine appears to have a greater tolerance than anchovy for low bottom temperature (Fig. 5) although it also appears to avoid cold pool waters.”
    Quote in the paperSubstantial claim
    • The authors state this as an assumption: If eggs are present in the water column, they will be found at 3 m depth where the CUFES operates; the presence/absence index used in the study can be considered a good proxy for presence or absence of eggs in the water column.
    • Rests on an assumption: The hydrodynamical model can realistically mimic hydrographic conditions.

  • May combine two claims.

    Findingnone given

    Sardine eggs can be found in coastal waters (shallow mixing depth and low stratification energy), but contrary to anchovy they are also found in areas of deep mixing and low stratification energy which correspond to thermal rather than haline stratification in early spring.

    “Sardine eggs can be found in coastal waters (i.e.shallow mixing depth and low stratification energy), but contrary to anchovy they are also found in areas of deep mixing and low stratification energy which correspond to thermal rather than haline stratification in early spring.”
    Quote in the paperSubstantial claim
    • The authors state this as an assumption: If eggs are present in the water column, they will be found at 3 m depth where the CUFES operates; the presence/absence index used in the study can be considered a good proxy for presence or absence of eggs in the water column.
    • Rests on an assumption: The hydrodynamical model can realistically mimic hydrographic conditions.

  • May combine two claims.

    Findingown data

    The modelled succession of spatial patterns for sardine is consistent with existing field observations, with potential spawning habitat showing a more fragmented distribution and covering a larger area than for anchovy and progressively extending northward as the season progresses.

    “The modelled succession of spatial patterns for sardine is also consistent with existing field observations, with 5 potential spawning habitat showing a more fragmented distribution and covering a larger area than for anchovy and progressively extending northward as the season progresses.”
    Quote in the paperSubstantial claim
    • The authors state this as an assumption: If eggs are present in the water column, they will be found at 3 m depth where the CUFES operates; the presence/absence index used in the study can be considered a good proxy for presence or absence of eggs in the water column.
    • Rests on an assumption: The hydrodynamical model can realistically mimic hydrographic conditions.

  • May combine two claims.

    Premisecitation

    Anchovy spawning occurs preferentially close to the coast and sometimes at the shelf break or in oceanic slope water eddies.

    “Anchovy spawning occurs preferentially close to the coast and sometimes at the shelf break or in oceanic slope water eddies (Motos et al., 1996).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Motos et al., 1996

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Premisenone given

    The impact of salinity has been little described for sardine populations.

    “The impact of salinity has been little described for sardine populations.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Stratification, retention and plankton production have been proposed as other controlling factors for anchovy spawning or spawning success in the Bay of Biscay.

    “Stratification, retention and plankton production have been proposed as other controlling factors for anchovy spawning (or spawning success) in the Bay of Biscay (Motos et al., 1996).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Motos et al., 1996

  • May combine two claims.

    Premisecitation

    Anchovy spawning is constrained by thermal environment, with reported thermal windows varying among studies (14-20°C, 16.5-19°C, 14-18°C).

    “Intensity of spawning appears to be constrained by thermal environment : Arbault and Lacroix (1977) have reported anchovy spawning within a thermal window of 14-20°C, Sola et al. (1990) have found a thermal window of 16.5-19°C whilst according to Motos et al. (1996) the thermal range is between 14 and 18°C.”
    Quote in the paperSubstantial claim0 of 3 sources checked
    • cites Arbault and Lacroix (1977)

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

    • cites Sola et al. (1990)

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

    • cites Motos et al. (1996)

  • May combine two claims.

    Premisecitation

    In the Bay of Biscay, sardine spawning occurs within a thermal window of 12.5-15°C according to Sola et al. (1990) and 10-16°C according to Arbault and Lacroix (1977).

    “In the Bay of Biscay, sardine spawning occurs within a thermal window of 12.5-15°C according to Sola et al. (1990) and of 10-16°C according to Arbault and 5 Lacroix (1977).”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites Sola et al. (1990)

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

    • cites Arbault and Lacroix (1977)

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim: may not pass S4 (based).

    Study design and conductnone given

    The simulations of potential spawning habitat rely heavily on the capability of the hydrodynamical model to mimic realistically hydrographic conditions.

    “The simulations of potential spawning habitat relies heavily on the capability of the hydrodynamical model to mimic realistically hydrographic conditions.”
    Quote in the paperNot a substantial claim
    • Rests on an assumption: The hydrodynamical model can realistically mimic hydrographic conditions.

  • May combine two claims.

    Interpretationreasoning

    It is likely that anchovy are not directly dependent on temperature close to the bottom, but because temperature displays little gradient below the thermocline, bottom temperature appears as a good proxy for conditions between the bottom and the thermocline.

    “It is likely that anchovy are not directly dependent on temperature close to the bottom, but since temperature displays little gradient below the thermocline, bottom temperature appears as a good proxy for the conditions between the bottom and 25 the thermocline.”
    Quote in the paperSubstantial claim
    • The authors state this as an assumption: If eggs are present in the water column, they will be found at 3 m depth where the CUFES operates; the presence/absence index used in the study can be considered a good proxy for presence or absence of eggs in the water column.
    • Rests on an assumption: The hydrodynamical model can realistically mimic hydrographic conditions.

  • May combine two claims.

    Study design and conductreasoning

    The field cruises are centred on the area and timing of spawning of anchovy and sardine and therefore include only a fraction of non-spawning sites and are limited in the range of hydrographic situations encountered.

    “Since the field cruises are primarily designed to monitor anchovy and sardine populations, they are centred on the area and timing of spawning of the two species and therefore include only a fraction of the non-spawning sites and are limited in the range of hydrographic situations encountered.”
    Quote in the paperSubstantial claim

  • Classified as probably not a substantial claim.

    Premisenone given

    There has yet been no quantitative assessment of the link between stratification, retention and plankton production and anchovy spawning.

    “However, there has yet been no quantitative assessment of the link between these factors and anchovy spawning.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    The genus Engraulis is found from estuaries to high salinity waters, so it is associated with coastal areas rather than with water of a given salinity range.

    “In his world-wide analysis of anchovy distribution, Reid (1966) argues that the genus Engraulis is found from estuaries to high salinity waters, so that it is associated with coastal areas rather than with water of a given salinity range.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Reid (1966)

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim: may not pass S2 (checkable), S3 (load-bearing). May combine two claims.

    Interpretationcitation

    Hydrographic conditions can be seen as providing the 'hydrographic envelope' of the spawning species, a notion related to the more general 'bioclimate envelope' or 'climate space'.

    “Such conditions can be seen as providing the 'hydrographic envelope' of the spawning species, a notion which can be related to the more general 5 'bioclimate envelope' or 'climate space' (see Pearson and Dawson, 2003 and references therein).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Pearson and Dawson, 2003 source

  • Classified as probably not a substantial claim. May combine two claims.

    Premisenone given

    Predicting potential spawning habitat is not predicting realised spawning and even less predicting spawning success, which depends upon adult population structure, biological conditions in the ocean, and environmental hydrodynamical conditions after spawning.

    “However, one must not forget that predicting potential spawning habitat is not predicting realised spawning and even 10 less predicting spawning success which depends upon adult population structure, biological conditions in the ocean (e.g.predators and preys) as well as environmental hydrodynamical conditions after spawning.”
    Quote in the paperSubstantial claim
37 of 37

  • The paper relies on this without support.

    Egg presence is a valid indicator of spawning.

    “The definition of potential spawning habitat is based on the existence of a relationship between hydrographic factors and the probability of egg presence.”

  • The paper relies on this without support.

    Spatial and seasonal extent of potential spawning habitat is primarily affected by variability in climate and the environment.

    “Spatial and seasonal extent of potential 5 spawning habitat will be primarily affected by variability in climate and the environment.”

  • The paper relies on this without support.

    GAM relationships fitted on 2000-2004 egg presence and hydrographic data can be applied to hydrodynamical simulations to predict potential spawning habitat.

    “Using the GAMs (constructed from observed egg distributions and hydrographic situations) it is possible to predict the probability of egg presence from a new set of hydrographic predictors.We have made such attempt using hydrographic results for hydrodynamical simulations.”

  • The authors state this as an assumption.

    If eggs are present in the water column, they will be found at 3 m depth where the CUFES operates; the presence/absence index used in the study can be considered a good proxy for presence or absence of eggs in the water column.

    “It therefore appears to be a reasonable assumption that if eggs are present in the water column they will be found at 25 3m depth where the CUFES operates, and the presence/absence index used in the present study can be considered as a good proxy for presence or absence of eggs in the water column.”

  • The paper relies on this without support.

    The hydrodynamical model can realistically mimic hydrographic conditions.

    “The simulations of potential spawning habitat relies heavily on the capability of the hydrodynamical model to mimic realistically hydrographic conditions.”

  • The paper relies on this without support.

    Adult fish biomass can potentially influence the spatial extent of spawning.

    “Another variable which can potentially influence the spatial extent of spawning is the biomass of adult fish spawning.”
6 of 6

Claims other papers make about this one

Each is checked against this paper’s own text: does it say what the citing paper says it does?

  • Similar mechanisms have been proposed for the spawning of European anchovy in the Mediterranean and in the Bay of Biscay.

    “Similar mechanisms have been proposed also for the spawning of European anchovy in the Mediterranean (Agostini and Bakun, 2002) and in the Bay of Biscay (Bellier et al., 2007;Planque et al., 2007).”

    From Evolutionary and ecological constraints of fish spawning habitats (2015) · cites this paper as Planque et al., 2007

  • Small pelagic species in the eastern Bay of Biscay and in the Benguela system display similar degrees of environmental flexibility in their reproductive locale.

    “Several other small pelagic species in the eastern Bay of Biscay (Bellier et al., 2007;Planque et al., 2007) and in the Benguella system (Kreiner et al., 2011) display similar degrees of environmental flexibility in their reproductive locale.”

    From Evolutionary and ecological constraints of fish spawning habitats (2015) · cites this paper as Planque et al., 2007

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

Each contradiction between two passages listed here was confirmed by an independent check.

  • Post-spawning effects attributed to realised habitat

    Minor

    The paper defines realised spawning habitat by where fish actually spawn and attributes its extent primarily to adult population characteristics. It then attributes effects on eggs, larvae and juveniles after spawning to realised habitat, although those effects belong to its definition of successful spawning habitat.

1 of 1

Cites

Flagged first, then by citations

1 of the 50 references couldn’t be matched to a known paper.

Research works printed but not linked: 11

  1. Ahlstrom E.H., 1965, A review of the effects of the environment of the Pacific sardine, ICNAF Spec. Publ., 6, 53
  2. Arbault S., 1967, Oeufs et larves de poissons téléostéens dans le golfe de Gascogne en 1964, Cons. Int. Explor. Mer., 11
  3. Arbault S., 1971, Aires de ponte de la sardine, du sprat et de l'anchois dans le golfe de Gascogne et sur le plateau Celtique. Résultats de 6 années d’études, Rev. Trav. Inst. Pêches Marit., 35, 35
  4. Arbault S., 1977, Oeufs et larves de clupeides et engraulides dans le golfe de Gascogne (1969–1973). Distribution des frayères. Relations entre les facteurs du milieu et la reproduction, Rev. Trav. Inst. Pêches Marit., 41, 227
  5. Fage L., 1911, Recherches sur la biologie de l'anchois (Engraulis encrassicholus Linné) ‐ races ‐ âge ‐ migrations, Ann. Inst. Océanogr., 2, 45
  6. R Development Core Team, 2004, A Language and Environment for Statistical Computing
  7. Reid J.L., 1966, Oceanic environment of the genus Engraulis around the world, CalCOFI Rep., 11, 29
  8. Sola A., 1990, Seasonal occurrence of pelagic fish eggs and larvae in the Cantabrian Sea (VIIIc) and Galicia (IXa) from 1987 to 1989, ICES CM, 1990, 14
  9. Stratoudakis Y., 2004, Sardine (Sardina pilchardus) spawning season in the North East Atlantic and relationships with sea surface temperature, ICES CM, 2004, 19
  10. Tibby R.B., 1937, The relation between surface water temperature and the distribution of spawn of the California sardine (Sardinops caerulea), Cal. Fish. Game, 23, 132
  11. Westgard T., 1989, Two models for the vertical distribution of pelagic fish eggs in the turbulent upper layer of the ocean, Rapp. P.-v. Réun. Cons. int. Explor. Mer., 191, 195

Cited by

Sorted by citations

Related

Authors
PLANQUE, B., BELLIER, E., & LAZURE, P.
Affiliations
Ifremer (FR)
Corresponding author
PLANQUE, BENJAMIN
Venue
Fisheries Oceanography
Publisher
Wiley
Published
2006-10-25
Volume
16
Issue
1
Pages
16-30
ISSN
  • 1054-6006 (ISSN-L)
  • 1365-2419
DOI
10.1111/j.1365-2419.2006.00411.x
OpenAlex
W1989989422
Semantic Scholar
fed6b7a7c0bdb0a57518f9ad49a1723e26462085
Cited by
184
References
50
Citations by year
2026: 8 · 2025: 16 · 2024: 9 · 2023: 4 · 2022: 11 · 2021: 6 · 2020: 12 · 2019: 5 · 2018: 7 · 2017: 14 · 2016: 10 · 2015: 8 · 2014: 17 · 2013: 5 · 2012: 13
FWCI
7.00
Type
journal article
Language
en
Open access
Licence
onlinelibrary.wiley.com/termsAndConditions#vor (vor)
Locations
  • Fisheries Oceanography (publishedVersion)
  • HAL (Le Centre pour la Communication Scientifique Directe) (submittedVersion)
  • Institutional Archive of Ifremer (French Research Institute for Exploitation of the Sea) (submittedVersion)
Topics
  • Physical Sciences › Environmental Science › Global and Planetary Change › Marine and fisheries research
  • Physical Sciences › Environmental Science › Nature and Landscape Conservation › Fish Ecology and Management Studies
  • Physical Sciences › Earth and Planetary Sciences › Oceanography › Oceanographic and Atmospheric Processes
Keywords
sardine, anchovy, Sardina pilchardus, Engraulis encrasicolus, hydrographic conditions, bottom water temperature, mixed layer depth, salinity, spawning seasonality, Bay of Biscay, Northeast Atlantic

About these checks

Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

Claims read by deepseek-v4.1-flash under definition version 3 (extract-v3) on 2026-10-16.

Classified by jev-1.13-20260917 (gold-guideline-v0.2) on 2026-10-16.

Cited sources are checked by gpt-6-sol.

Statistics and arithmetic are recomputed, not judged.

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