In 1998 Daniel Pauly and co-workers published a paper in Science describing the concept of fishing down the food chain using FAO landings data. Recent and forthcoming publication of papers using ICES landings data demonstrate that fishing down the food chain in UK waters is now a reality and that its impacts are wide ranging not least on the fishing sector. In a recent paper Jason Hall Spencer, Carlotta Molfese & Doug Beare (see below) have highlighted growth in shellfisheries in the English Channel and the gradual decline of demersal fish landings.  In the Clyde and the Irish Sea work by Callum Roberts and his team will illustrate the impacts of Nephrops (scampi) and scallop fishing on declining demersal landings.

These findings pose challenges to many of the current UK marine programmes for example:

1. The Government’s vision is for: clean, healthy, safe, productive and biologically diverse oceans and seas. Put simply what these findings do is to beg the question about whether the Government’s long standing vision for our seas is being achieved.

2. The Marine Strategy Framework Directive requires that European Governments implement policies to achieve good environmental status (GES) by 2020. Four of the descriptors are being heavily impacted by current fisheries practice including:

  • Descriptor 1   Biodiversity
  • Descriptor 3   Commercially exploited fish and shellfish
  • Descriptor 4   Food webs
  • Descriptor 6   Sea floor integrity

Government are to consult on measures to achieve GES early in the New Year but analysis reveals that fishing is still the major issue to address.

3. Fisheries Policy    The Government in its long term policy for the fishing sector as its first guiding principle sets out the need for economic optimisation (Defra: Fisheries 2027). The reality is that whilst shellfish landings in the Irish Sea for example have remained relatively constant demersal fish landings are 10% of what they were in 1990. This hardly seems optimal for fishermen … or anything else.

4. Marine planning provides us with a mechanism for setting out our vision, collective policies and direction of travel. Are we planning to maintain fishing down the food chain as the status quo or can we act to recover demersal fisheries

Through these programmes measures can be introduced that reverse this situation. We have the ability to change direction in a positive and constructive way. I wonder whether we will take it?

Bob Earll,  August 2014


Overfishing and the Replacement of Demersal Finfish by Shellfish: An Example from the English Channel

Carlotta Molfese, Doug Beare and Jason M Hall Spencer

Summary:   The worldwide depletion of major fish stocks through intensive industrial fishing is thought to have profoundly altered the trophic structure of marine ecosystems. Here we assess changes in the trophic structure of the English Channel marine ecosystem using a 90-year time-series (1920–2010) of commercial fishery landings. Our analysis was based on estimates of the mean trophic level (mTL) of annual landings and the Fishing-in-Balance index (FiB). Food webs of the Channel ecosystem have been altered, as shown by a significant decline in the mTL of fishery landings whilst increases in the FiB index suggest increased fishing effort and fishery expansion. Large, high trophic level species (e.g. spurdog, cod, ling) have been increasingly replaced by smaller, low trophic level fish (e.g. small spotted catsharks) and invertebrates (e.g. scallops, crabs and lobster). Declining trophic levels in fisheries catches have occurred worldwide, with fish catches progressively being replaced by invertebrates. We argue that a network of fisheries closures would help rebalance the trophic status of the Channel and allow regeneration of marine ecosystems.

Spreadsheet of   data

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