Scottish Marine and Freshwater Science Volume 3 Number 3: Clyde Ecosystem Review

2. INTRODUCTION

2.1.1 An Ecological Desert - Thurston and Roberts (2010)

In July 2010 a scientific paper authored by researchers from York University was published, entitled,

Ecological Meltdown in the Firth of Clyde, Scotland, Two Centuries of Change in a Coastal Marine Ecosystem
(Thurston and Roberts, 2010).

This stimulated immediate media interest (Glasgow Herald and Sunday Times articles, Radio 5 live) and a BBC Panorama programme in August. Newspaper headlines at the time included;

Clyde cleaned out to become marine desert (The Sunday Times, 11 July 2010)

Clyde ecosystem in meltdown (The Herald, 12 July 2010)

Report warns Clyde is fished out (Glasgow Evening Times, 12 July 2010)

Subsequently the Scottish Government held various meetings with local stakeholders around the Clyde to discuss the implications of the published study. Following these initial meetings, on the 1 October 2010, at the Ardoe House Hotel near Aberdeen, Mr Richard Lochhead (Cabinet Secretary for Rural Affairs and the Environment) met with scientists from Marine Scotland Science ( MSS) in order to discuss possible avenues of research into the conditions of the Clyde Sea ecosystem. At that time it was considered too early to commission externally contracted work. Instead MSS were asked to carry out an initial internal review and propose a way forward.

Following the meeting MSS scientists commenced an assessment of the work needed and a collation of available data sets. A principal relevant data set identified was that derived from the catches recorded during research vessel surveys which Marine Scotland Science, and its predecessors at the Marine Laboratory Aberdeen, have carried out since the 1920s. However, at that time no staff resource was immediately available to complete the work needed and a recruitment process commenced which resulted in the appointment of a temporary researcher, Ms Fiona McIntryre, on an 11 month contract. Ms McIntyre commenced work on 10 January 2011 supervised by Dr Paul Fernandes.

2.1.2 A Changed Ecosystem - Heath and Speirs (2011)

Independently from the process underway within Marine Scotland, the University of Strathclyde also commenced work on the issue of the ecological status of the Clyde. While Thurston and Roberts (2010) relied entirely on landings data, Professor Mike Heath of the University of Strathclyde contacted Marine Scotland Science to request the research vessel survey data noted above. This was provided, and as a result of a detailed and well-found analysis, in July 2011 Professor Heath published a definitive analysis of the present state of the Clyde Sea demersal fish community in his paper, with Dr Doug Speirs, entitled,

Changes in species diversity and size composition in the Firth of Clyde demersal fish community (1927-2009)
(Heath and Speirs, 2011)

Although a comprehensive statement on the status of the Clyde ecosystem, this paper did not attract the media attention received by Thurston and Roberts (2010). This, unfortunately, reflects the nature of how science is covered in today's media, which in many instances appears agenda-driven rather than representing objective reporting of scientific progress.

The conclusions of Heath and Speirs (2011), although expressed in less emotive terms than Thurston and Roberts (2010), nevertheless point to a major ecological impact of fishing in the Clyde. The picture portrayed by Heath and Speirs is not one of an ecological desert, but of an altered ecosystem. Their principal conclusions were,

- rather than commercial species being entirely removed from the Clyde, the biomass of the six main commercial species in the late 2000s was approximately double that prior to the onset of trawling in the 1960s.

- however, the size structures of these species were dramatically different, being markedly deficient in large commercially marketable individuals after the period of peak harvesting rates in the 1980s

- also the incidence of species with a maximum attainable length greater than 40 cm declined precipitously and did not recover during the period of low harvesting rates after the late 1990s possibly owing to internal predator-prey interactions.

This means that the Clyde Sea still functions as an ecosystem. Primary production still occurs, powered by the sun and supplied by water-borne nutrients, which sustains secondary zooplankton production, which in turn feeds an active food web. The Clyde is not an ecological desert.

However, the Clyde ecosystem has been changed. The biomass of fish in the Clyde is the same, or for some species more, than when intensive fishing started. Additionally, a large and healthy population of shellfish ( Nephrops) living on the sea bed of the Clyde is present. However, the community of fish is now made up mostly of small fish, and mostly small whiting. If we were to seek a terrestrial analogy it would not be that of a desert. Rather it might be that of used agricultural land in need of restoration. Comparing the Clyde to an ecosystem modified by human use yet capable of restoration portrays a much less news-worthy image than an ecological desert.

The Clyde ecosystem is one that has been used by humans for centuries, and hence it is changed. But humans can also now influence the direction the ecosystem takes by managing human activities in the future, precisely because the Clyde is not an ecological desert, but is an active ecosystem with great potential for future sustainable use.

2.1.3 This Report

With the publication of Heath and Speirs (2011), the role of this report changed. Significant staff changes during the life of the project have resulted in additional changes to the direction and timing of this work, as both Dr Paul Fernandes and Ms Fiona McIntyre left to pursue academic careers.

Hence this report now has the following objectives,

1. To present a brief review of previously published information and knowledge concerning the Firth of Clyde ecosystem.
2. To present the findings of Heath and Speirs (2011) in a format accessible to stakeholders and managers.
3. To propose a data tool which may help inform future management options in the Clyde.
4. To make suggestions for further studies in the Clyde required in order to support sustainable use of this active Scottish marine ecosystem

In some respects this report marks the start of a process, rather than the conclusion of one. It poses more questions than it answers, and presents preliminary analysis of a new data set that requires further validation, checking and expansion.

However, it provides a start point from which government and stakeholders concerned with the future of the Clyde can build upon and progress. It puts into context some secondary issues which may cloud the primary focus of future work to recover the Clyde ecosystem; how we manage fisheries in the Clyde.