Elsevier

Fisheries Research

Volume 50, Issues 1–2, February 2001, Pages 27-40
Fisheries Research

Seasonal and ontogenetic changes in the vertical distribution of eggs and larvae of mackerel (Scomber scombrus L.) and horse mackerel (Trachurus trachurus L.)

https://doi.org/10.1016/S0165-7836(00)00240-XGet rights and content

Abstract

Results are summarised from vertical distribution sampling for eggs and larvae of mackerel (Scombrus scombrus) and horse mackerel (Trachurus trachurus) to the west of the British Isles and in the Bay of Biscay between 1974 and 1995. Eggs of both species were predominantly in the upper 50 m of the water column and generally in increasing numbers towards the surface. For both mackerel and horse mackerel, the eggs had a deeper distribution earlier in the spawning season when there was little thermal stratification and became progressively more restricted to the surface layers as stratification developed. Eggs at the latest stages of development tended to be deeper in the water column than earlier stages and exhibited a sub-surface peak of abundance. Larvae of both species were also concentrated in the upper 50 m of the water column above the seasonal thermocline and exhibited sub-surface peaks of abundance in the depth range of 10–30 m. There was little evidence of diel migration for larvae of either mackerel or horse mackerel. The optimum sampling depth for quantitative egg surveys is discussed.

Introduction

Information on the vertical distribution of fish eggs and larvae is an essential pre-requisite for efficient sampling, e.g. for stock estimation based on plankton egg surveys (Lockwood et al., 1981). Equally, a knowledge of their vertical distribution is required for studies of transport and survival of eggs and larvae in relation to current systems and biological processes in the water column. In the latter context, an EU funded programme (SEFOS — Shelf-Edge Fisheries and Oceanography Studies) has been designed to study the effects of the shelf-edge current on fish stocks from Portugal through Biscay and west of the British Isles to Norway. One aspect of the SEFOS programme was an investigation of the distribution and advection of the planktonic stages of mackerel (Scomber scombrus) and horse mackerel (Trachurus trachurus) in relation to their subsequent recruitment. The present work on the vertical distribution of the eggs and larvae is a part of this study.

Spawning of both mackerel and horse mackerel is widespread over much of the European shelf, extending from the North Sea and west of Scotland as far south as the coasts of Spain and Portugal (Lago de Lanzós et al., 1993; Anon., 1994) and, for horse mackerel to waters off West Africa (Eaton, 1983; John et al., 1991). For both species the highest incidence of spawning is at the shelf-edge and over adjacent shelf regions of the Celtic Plateau and Biscay, the main spawning season in these areas for mackerel being from mid-April to mid-June (Anon., 1993, Anon., 1996), and for horse mackerel somewhat later, from May to July (Eaton, 1989; Franco et al., 1993; Anon., 1996).

Reports on the vertical distribution of mackerel eggs west of the British Isles have shown that once thermal stratification is present they are distributed mostly in the upper mixed layer above a depth of about 100 m (e.g. Coombs et al., 1981, Coombs et al., 1990; Anon., 1993). A similar but more extreme restriction of eggs to the upper 10 or 20 m of the water column has been observed for mackerel eggs in other regions when stratification is well developed (e.g. North Sea — Iversen, 1977; Coombs et al., 1981; English Channel — Southward and Barrett, 1983; east coast of North America — Sette, 1943; Lafontaine and Gascon, 1989). More limited information on their depth distribution in the absence of any appreciable thermal stratification has indicated that under such conditions, eggs are found at greater depths (Walsh, 1976; Coombs et al., 1981; Röpke, 1989). Larvae have been reported consistently as being in the upper mixed layer (e.g. Sette, 1943; Coombs et al., 1981, Coombs et al., 1983, Coombs et al., 1990; Southward and Barrett, 1983; Ware and Lambert, 1985; Lafontaine and Gascon, 1989; Röpke, 1989).

Less information is available on the vertical distribution of eggs and larvae of horse mackerel and much of this is derived from widely distributed sites away from the main spawning grounds along the northern European shelf-edge. However, there is a consistency in the observation of increased abundance of both eggs and larvae towards the surface (e.g. off Portugal — John and Ré, 1993; off West Africa — John, 1985; John et al., 1991; in the English Channel — Russell, 1930; Southward and Barrett, 1983; at the shelf-edge in Biscay — Coombs et al., 1979). Concentrations of eggs and larvae in the neuston have also been noted (e.g. in the North Sea — Nellen and Hempel, 1970; in the Black Sea — Zaitsev, 1971). A similar near-surface habit has been described for the early developmental stages of other Trachurus species (e.g. Trachurus symmetricus off California — Ahlstrom, 1959; Trachurus trachurus capensis in the northern Benguela system — Olivar, 1990).

However, few of the above sets of results have included sufficient coverage for a comprehensive description or statistical analysis of the depth distribution of eggs or larvae. The purpose of the present paper is to summarise the results from sampling to the west of the British Isles and to provide a more complete description of their vertical distribution. Preliminary accounts were given in Coombs et al., 1996a, Coombs et al., 1996b.

Section snippets

Materials and methods

Sampling was carried out at the shelf-edge and adjacent areas west of the British Isles and in Biscay between March and June on various cruises between 1974 and 1991 (Fig. 1 and Table 1). A more detailed set of samples was obtained over a 33 h period in June 1995 at a site in the Porcupine Seabight to the southwest of Ireland (Fig. 1 and Table 1).

All sampling was carried out using versions of the Longhurst-Hardy Plankton Recorder (Williams et al., 1983; see also Pipe et al., 1981) which takes a

Results

There was a progressive change in the mean depth of mackerel eggs over the spawning season (F3,83=22.86, p=0.0001). In March and April, eggs were distributed over a wide depth range to at least 400 m depth, while in May and June they were in shallower depths, mostly in the upper 50 m of the water column (73.0% of eggs in the 0–50 m depth range in May and 81.6% in June; Fig. 2, Fig. 3). These changes in vertical distribution corresponded to development of the seasonal thermocline, little vertical

Discussion

The observed relatively near-surface distribution of mackerel and horse mackerel eggs and larvae, at least in May and June, is typical of ichthyoplankton in general (e.g. Boehlert et al., 1985; Conway et al., 1997). The relatively deep distribution of mackerel eggs, as observed in March and April (>200 m depth) is less common, and usually confined to habitually deep-water species, or to those found at depth during the spawning season (e.g. blue whiting, Micromesistius poutassou, Coombs et al.,

Acknowledgements

The authors gratefully acknowledge the assistance given by the following organisations to participate in their cruises: Fisheries Laboratory Lowestoft, Marine Laboratory Aberdeen, Institute for Marine Research Bergen, Institut für Meereskunde Kiel, Institut für Seefischerei Hamburg and Station Biologique Roscoff. Funding for the work has been provided in part under EU contract AIR2-CT93-1105.

References (43)

  • S Sundby

    A one-dimensional model for the vertical distribution of pelagic fish eggs in the mixed layer

    Deep-Sea Res.

    (1983)
  • R Williams et al.

    The double LHPR system, a high speed micro- and macroplankton sampler

    Deep-Sea Res.

    (1983)
  • Ådlandsvik, B., Coombs, S., Sundby, S., Temple, G., 2001. Bouyancy and vertical distribution of eggs and larvae of blue...
  • E.H Ahlstrom

    Vertical distribution of pelagic fish eggs and larvae off California and Baja California

    Fish. Bull.

    (1959)
  • Anon., 1993. Report of the mackerel/horse mackerel egg production workshop. ICES CM 1993/H:4, 142...
  • Anon., 1994. Report of the mackerel/horse mackerel egg production workshop. ICES CM 1994/H:4, 58...
  • Anon., 1996. Report of the working group on mackerel and horse mackerel egg surveys. ICES CM 1996/H:2, 146...
  • G.W Boehlert et al.

    The vertical distribution of ichthyoplankton off the Oregon coast in spring and summer months

    Fish. Bull.

    (1985)
  • D.V.P Conway et al.

    Vertical distribution of fish eggs and larvae in the Irish Sea and North Sea

    ICES J. Mar. Sci.

    (1997)
  • Coombs, S.H., Pipe, R.K., Mitchell, C.E., 1979. The vertical distribution of fish eggs and larvae in the eastern North...
  • S.H Coombs et al.

    The vertical distribution of eggs and larvae of blue whiting (Micromesistius poutassou) and mackerel (Scomber scombrus) in the eastern North Atlantic and North Sea

    Rapp. P.-v. Réun. Cons. Int. Explor. Mer.

    (1981)
  • Coombs, S.H., Lindley, J.A., Fosh, C.A., 1983. Vertical distribution of larvae of mackerel (Scomber scombrus) and...
  • S.H Coombs et al.

    The aetiology of mackerel spawning to the west of the British Isles

    Meeresforsch.

    (1990)
  • Coombs, S.H., Morgans, D., Halliday, N.C., 1996a. The vertical distribution of eggs and larvae of mackerel (Scombrus...
  • Coombs, S.H., Conway, D.V.P., Halliday, N.C., 1996b. The vertical distribution of eggs and larvae of horse mackerel...
  • Eaton, D.R., 1983. Scad in the North-East Atlantic. Lab. Leafl. MAFF Direct. Fish Res., Lowestoft No. 56, 20...
  • D.R Eaton

    Spawning-stock biomass of scad (Trachurus trachurus L.) to the west of the British Isles, as indicated by egg surveys

    J. Cons. Int. Explor. Mer.

    (1989)
  • Franco, C., Motos, L., Sola, A., Lago de Lanzos, A., 1993. Horse mackerel (Trachurus trachurus L.) egg distribution and...
  • D.G George

    Interrelations between the vertical distribution of Daphnia and chlorophyll a in two large limnetic enclosures

    J. Plankton Res.

    (1983)
  • T Haug et al.

    Influence of some physical and biological factors on the density and vertical distribution of Atlantic halibut Hippoglossus hippoglossus eggs

    Mar. Ecol. Prog. Ser.

    (1986)
  • Iversen, S.A., 1977. Spawning, egg production and stock size of mackerel (Scomber scombrus L.) in the North Sea...
  • Cited by (41)

    • Species acclimatization pathways: Latitudinal shifts and timing adjustments to track ocean warming

      2023, Ecological Indicators
      Citation Excerpt :

      Subsequently, we analysed phenological and latitudinal changes in spawning activity throughout time and in relation to interannual sea temperature variation and density dependence. Eggs of horse mackerel and Atlantic mackerel species are predominantly found in the upper 10–20 m of the water column (Coombs et al., 2001). Considering this, we characterized the potential impact of climate warming on the spawning activity of horse mackerel and Atlantic mackerel using daily retrievals of the temperature of the ocean surface from NOAA Optimum interpolation 0.25° daily sea surface temperature analysis (DOISST version 2.1, Sep. 1981–present) (Huang et al., 2021).

    • The bay of biscay

      2018, World Seas: An Environmental Evaluation Volume I: Europe, the Americas and West Africa
    • Comparative ecology of widely distributed pelagic fish species in the North Atlantic: Implications for modelling climate and fisheries impacts

      2014, Progress in Oceanography
      Citation Excerpt :

      A deeper understanding of the main drivers of the highly dynamic mackerel distribution patterns remains elusive. Free floating eggs of NEAM mackerel occur deeper early in the spawning season when there is little thermal stratification (Röpke, 1989; Coombs et al., 2001). As stratification develops, eggs become progressively more restricted to the surface layers (Coombs et al., 2001).

    • Temperature affects the timing of spawning and migration of North Sea mackerel

      2011, Continental Shelf Research
      Citation Excerpt :

      In the North Sea mackerel eggs are distributed in the upper part of the water column and more than 90% of the eggs are found in the upper 12–13 m (Iversen, 1977). However, spawning probably occurs close to the thermocline from where the positively buoyant eggs subsequently float upwards (Coombs et al., 2001; De Lafontaine and Gascon, 1989; Myrberget, 1965; Nilsonn, 1914). The ICES CTD data show that in most years a thermocline is present in the North Sea in May at depths of between 10 and 40 m while in June a thermocline is always present at 15–30 m. To examine the relationship between SST and the temperature at the depths where mackerel are likely to spawn we tested whether there was a significant positive correlation between North Sea SST and the temperature at 3–20 and 20–40 m of depth in May and June.

    View all citing articles on Scopus
    View full text