The forth estuary: a nursery and overwintering area for North Sea fishes

Abstract

The fish community of the Forth estuary, Scotland, has several components -estuarine resident species, diadromus migratory species, marine and freshwater adventitious species, marine juvenile migrants using the area as a nursery, and adults of marine species with seasonal migrations. The population changes during the period 1981-88 in six species representative of the last two categories are described here. The species are the juvenile gadoids, whiting, Merlangius merlangus (L.) and cod, Gadus morhua L., juvenile flatfish, plaice, Pleuronectes platessa L. and common dab, Limanda limanda (L.), and the adult clupeids, sprat, Sprattus sprattus (L.) and herring, Clupea harengus L.The species' population changes are described in relation to aspects of wider significance such as commercial fishing for these species in North Sea areas. In particular, the underlying decline of the juvenile cod populations since 1981 in the Forth Estuary is discussed in relation to the recent reduction in commercial fishing quotas.

Life strategies of fishes in European estuaries: the functional guild approach

“…The estuaries included here were sampled mainly by bed trawling or netting over the bed, methods which could underestimate the number of pelagic or planktivorous species (Elliott & Dewailly 1995). However, Elliott et al (1990) showed that bed trawling in shallow estuarine areas takes a representative pelagic population, at both qualitative and quantitative levels (Elliott & Dewailly 1995). Furthermore, as this study relied on a qualitative approach (species occurrence), some differences are expected when applying it to quantitative information (species abundances).…”

“…Furthermore, as this study relied on a qualitative approach (species occurrence), some differences are expected when applying it to quantitative information (species abundances). For example, marine stragglers are typically represented by high numbers of species, but very low numbers of individuals (Elliott et al 1990), while planktivorous species may be highly represented owing to the large numbers of, e.g., clupeoids, which inhabit estuaries for part of the year (Elliott & Dewailly 1995).…”

Fish assemblages of European tidal marshes: a comparison based on species, families and functional guilds

“…Estuaries have long been recognised as areas which naturally support high densities and production levels of fish, as permanent residents, during migration, or Naismith & Knights 1988, Elliott et al 1990 or which support fish species of international conservation value (e.g. Maitland 1974, Aprahamian 1988, anthropogenic pressures continue to threaten the integrity and quality of estuaries world-wide (McLusky 1989, GESAMP 1997.…”

Habitat choice by juvenile cod (Gadus morhua L.) on sandy soft bottoms with different vegetation types

“…Another factor which makes shallow coastal habitats favourable as a nursery area is the high productivity of benthos that can be utilized as food resource by both permanent and temporary inhabitants (Pihl & Rosenberg, 1982;Baden & Pihl, 1984;Jansson et al, 1985). This dependence on shallow bottoms in many juvenile marine species makes them vulnerable to several threats, including the loss of habitat and feeding areas (Elliott et al, 1990).…”