ICES Journal of Marine Science: Journal du Conseil Advance Access originally published online on April 30, 2007
ICES Journal of Marine Science: Journal du Conseil 2007 64(4):686-692; doi:10.1093/icesjms/fsm045
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Comparison of two periods of North Sea herring stock management: success, failure, and monetary value
FRS Marine Laboratory, PO Box 101, Victoria Road, Aberdeen, Scotland AB11 9DB, UK
tel: +44 1224 295366; fax: +44 1224 295511; e-mail: j.simmonds{at}marlab.ac.uk
Simmonds, E. J. 2007. Comparison of two periods of North Sea herring stock management: success, failure, and monetary value. – ICES Journal of Marine Science, 64: 686–692.At two points in the past (1970 and 1995), North Sea herring (Clupea harengus) abundance and catches have been in a similar situation: the stock had declined from an earlier high and reached a depleted state with a spawning-stock biomass of around 400 000 t, well below the agreed biomass limit reference point of 800 000 t. Catches were also similar at 600 000 t annually, and too high to be sustainable. A comparison of the scientific advice, the management actions, and their effects on population trends over the periods following these two critical years provides insight into important management issues. The benefits to the industry of the value of the cumulative catch resulting from successful management of this large stock have been proven to outweigh by far the costs of obtaining good management advice. The conclusion is that sound scientific information plays an important role when difficult management issues have to be confronted. However, there are other critical issues, such as the stakeholders' wish to preserve the stock at all costs and a management organization that has authority to take decisions.
Keywords: cost-benefit analysis, North Sea herring, stock management
Received 30 June 2006; accepted 26 January 2007; advance access publication 30 April 2007.
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Introduction |
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 Top Introduction General descriptionComparison of stock projection...Costs and benefits of...ConclusionsReferences |
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For hundreds of years, herring (Clupea harengus) have been an important source of food and economic wealth in Europe, with the Baltic and North Sea resources contributing to the development of the Hanseatic League during the 14th–16th centuries, and conflicting interests in the North Sea herring fishery being one of the causes of the war between UK and the Netherlands in the 16th century (Tracy, 1993). Historical detail for the period 1600–1860 is provided by Poulsen (2006), who concludes that, although the fisheries met periods of hardship, they have had a negligible impact on the stock. By the 1950s, however, the North Sea herring fisheries had expanded to a level at which they were bound to have a major impact on the stock. Between 1960 and 2003, the stock experienced two periods of severe exploitation. After reviewing management actions from 1964 to 1978, Saville and Bailey (1980) concluded that the fisheries had been the major cause of extreme stock depletion. Bjoerndal and Conrad (1987) went even further and suggested that the stock would have become extinct if the fishery had not been closed in 1978. The second period of major decline was in the mid-1990s, and again high fishing mortality (F) was the major cause. During both periods, the stock declined to well below the minimum spawning-stock biomass (SSB) required to ensure average recruitment (Figure 1). This reference level was described in the 1980s and 1990s as the minimum biologically acceptable level (Mbal: set at approximately one-third of the unexploited biomass), and more recently as Blim (the SSB level below which empirical evidence indicates that recruitment will be reduced).
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During the first period of excess fishing, no management action and a plummeting stock resulted in 1978 in total collapse and a closure of the entire fishery, followed by a slow recovery. The second resulted in an EU/Norway agreement on management actions introduced in 1997, and by 2003 the stock had recovered without requiring temporal closures. Using information on estimated catches and recommended and agreed total allowable catches (TACs) from assessment Working Group reports, and drawing on the ICES Advice and on the implementation of management decisions, I contrast these two periods and compare the cumulative monetary value of the catches and the costs of science to demonstrate the benefits of improved management. I conclude with a discussion of those aspects that were critical for management to succeed in pursuing its objectives.
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General description |
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TopIntroductionGeneral descriptionComparison of stock projection...Costs and benefits of...ConclusionsReferences |
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In 1970, the stock and the catch were similar to those observed in 1995 that triggered the major management change in 1996 (Figure 1; ICES, 2004). Figure 2 contrasts the stock development in terms of recruitment (R), SSB, catch, and F through both 8-y periods leading up to these years and the 8-y periods thereafter. During the pre-1970 and pre-1995 periods, mean R differed by just 1%. This similarity provides no evidence of a major change in recruitment patterns, although annual values vary because of environmental effects. These environmental effects are difficult to disentangle. Nash and Dickey-Collas (2005) found no clear relationship between survival of juvenile herring and the abundance of Calanus finmarchicus (an important food source), but they did find a negative relationship between year-class strength and bottom temperature (lower temperatures being associated with higher abundance of Calanus). Their analysis shows that year-class strength is largely determined between the larval and the juvenile stages. Although the cause is uncertain, the reduction of average R at low SSB is well established.
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The two periods exhibit similarly high rates of exploitation of catch, increases in F to > 0.6, and a reduction in SSB to well below 800 000 t (Mbal/Blim). Highlights of the information from assessments and scientific advice and associated management action by year are contrasted for the two periods in Table 1, which also lists the sources.
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The periods running up to 1970 and 1995 (which, in hindsight, appear to have been critical for management action) show considerable similarity, but some features differ. The 1960s were characterized by 4 y of high exploitation, followed by 5 y of increasing concern as the geographic centre of the fishery moved north. The scientific advice was disputed, and several requests and proposals were made for better science, which served only to delay decision-making. Management considerations were primarily related to area or seasonal closures, without any insight into the utility of such measures. In the end, no substantive management action was taken to reduce the fishery, despite sufficient evidence to indicate that F was too high for yields to be sustainable (total mortality being close to Z = 1), and F = 0.4 being suggested as a more rational target. Similarly in the late 1980s and early 1990s, scientists reported a moderate to large stock size, and fishing exceeded agreed TACs by estimated factors of 1.35. Some uncertainty in the assessment was noted, and advice was given that a target F of 0.3 would be sustainable in the long term. However, the recommended TACs did not particularly reflect the long-term advice. Even when the decline in the stock had become clear by 1994, the tone and the content of the advice remained the same: no alarm bell rang.
For the period 1987–2003, an indication of the degree of correspondence between the recommended and agreed TACs and the estimated catch can be derived from Figure 3. The recommended TAC has generally been accepted by the Council of Ministers after consultation with Norway. The catches have always been larger than the agreed TAC by 20% on average. Excess catches were mainly estimated from evidence of area misreporting, catches from the North Sea being reported from almost all surrounding areas. However, even the data currently available may be incomplete, and additional non-reported catches may have been taken.
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Equivalent detail on the relationship between advice and estimated catch is absent for the period 1962–1977, because, at that time, the fishery remained effectively unregulated (no catch limits were set, and effort regulations were restricted to small seasonal closures, which cannot be translated into explicit estimates of catch reduction).
Seen in retrospect, the herring stock had reached a critical stage in both 1970 and 1995: SSB had declined to a level at which there was a high probability of reduced recruitment (Figure 2). However, in 1970 there was no firm evidence yet of a stock-recruitment relationship, and the advice contained warnings rather than pointers to imminent danger. Because of constitutional constraints, the responsible management agency was not in a position to set catch limits, fishing continued, and the stock collapsed. In contrast, and following a much more explicit statement from ICES about the seriousness of the situation, action was taken to reduce catches in 1996, and the TAC was halved in-year. In 1997, a harvest control rule (HCR) was agreed (Patterson et al., 1997). This approach had been suggested earlier by Kunzlik and Bailey (1986), but its adoption by managers was a novum for European fisheries at the time (Buhl-Mortensen and Toresen, 2001). Its implementation led first to a reduction in F, then the stock started to rebuild while recruitment remained largely unaffected.
During the 1970s, the Northeast Atlantic Fisheries Commission (NEAFC) had attempted to reach agreement on a TAC, but was unable to do so because initially it had no constitutional remit to implement such a measure. Earlier attempts to adopt this management tool did not receive sufficient support from national delegates. Only when the stock had already dropped too low was the constitution finally amended, and a formal TAC could be imposed, provided enough delegates agreed. In practice, however, a TAC would only be agreed if it was unrestrictive. The NEAFC reports show the President's desperation as he tried to persuade delegates of the need for action (Table 1). In response, some delegates cited the short-term economic losses of reducing catches as the main reason that restrictions were unacceptable, without considering the longer term biological and economic consequences, and this tendency exists even today (Christensen and Lassen, 2004). When reviewing the 1970s, it is clear that the flexibility of management to consider economic and social trade-offs diminished to zero as the stock declined and the fishery had to be closed in 1978, creating a medium-term loss that outweighed any of the short-term losses that would have been suffered earlier if appropriate action had been taken. In contrast, medium-term economic benefit was obtained from restrictions in the short term in the late 1990s, when action was indeed taken.
The scientific advice in the late 1990s was not perfect. The true F was underestimated and the assessment failed to track accurately the changes in stock and fishery following the change in management. Although F did not reach its recommended level until 2002, the substantial reduction (Figure 2) was enough to halt the decline in SSB and to keep R around the average level, so allowing the fishery to continue. The scientific basis of the advice had improved considerably compared with the 1970s, when the absence of scientific information on the effect of the industrial fishery was used as an excuse to delay action and to await the results of proposed tagging studies, although the estimates of total mortality indicated that exploitation was far too high. Improved science coupled with more effective management helped to deliver a recovered stock in 2003, in sharp contrast to the outcome of a depleted stock and closure of the fishery in 1978 (Table 1).
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Comparison of stock projection in 1996 and actual development |
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TopIntroductionGeneral descriptionComparison of stock projection...Costs and benefits of...ConclusionsReferences |
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An important question is whether the scientific advice in the recent period is accurate enough to make reliable medium-term predictions of the state of the stock. Figure 4 compares a medium-term stochastic prediction using the program STPR3 (Skagen, 2004), based on the 1996 assessment and the agreed HCR with the actual trajectories of R, catch, SSB, and F. The trajectories are those estimated from the 2004 assessment (assuming + 10% assessment error in the final year tapering to 0% back to 1996), and they may be subject to further revision. All input data were those available in 1996, but implementation bias in the fishery (20%) and assessment bias (10%) have been estimated from the subsequent period. Although the implementation error was approximately the same for the period up to 1995, the assessment bias was unknown then because the method was relatively new and untested. From 1996, observed R was relatively low during the first 2 y, but overall, the eight R-values fall within the projected range and the mean value corresponds quite closely to the historical average (4% difference). F remained higher than the agreed target during the early years, but declined from 1998 to 2002, when catch was held constant while SSB increased. Part of the higher F resulted from underestimates in the assessment (overestimates of SSB), which reduced the effectiveness of the HCR applied in controlling F. This bias was corrected in subsequent assessments (ICES, 2004). SSB followed a trajectory well away from the median line, in part, because of the same assessment bias, but mostly because recruitment was initially below average. Despite these deviations, the reconstruction shows that the predicted effects of the agreed policy have corresponded quite well to the recovery realized.
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Costs and benefits of good management |
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TopIntroductionGeneral descriptionComparison of stock projection...Costs and benefits of...ConclusionsReferences |
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The total catches from 1970 to 1978 inclusive (2.98 million tonnes) and from 1996 to 2003 inclusive (4.4 million tonnes) show that the stock had already yielded some 1.4 million tonnes more during the latter (and 1-y shorter) period. The state of the stock is now relatively healthy, implying that yields are likely to remain moderate for at least the next few years. The current gains in yield amount to about
470 million over the 9-y period. This value should be compared with some 3.5 million spent annually on science (including research vessel surveys, and market and discard sampling, but excluding the capital costs of vessels; Anon., 2007). Therefore, the scientific advisory costs are at about 8% of the accrued additional benefit of good management and at 2.5% of the total value of landings at first sale. If the combination of science and management can maintain the stock in such a healthy state, these gains in yield should be sustainable as long as recruitment remains at an average level. |
Conclusions |
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TopIntroductionGeneral descriptionComparison of stock projection...Costs and benefits of...ConclusionsReferences |
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Scientific knowledge of the North Sea herring stock has been sufficient to provide reasonable management advice from the mid-1990s to the present. Management through TACs has always had substantial implementation error, but not to the extent that it impeded any recovery of the stock. In retrospect, the HCR has performed within the expected range, indicating that the assessment and the advice was consistent. The earlier failure to manage the stock resulted in a considerable reduction in yield and revenue to the fishery. At 2.5% of the landed value, the cost of the science and scientific advice has been only a small part of the added value through better management. The main message to fisheries management is that successful recovery in 6 y came from: (i) sufficiently believable science; (ii) a management system capable of taking consistent decisions; (iii) willingness of management and industry to take action, possibly aided by collective memory of the earlier collapse; and (iv) sustained reasonable recruitment. The key conclusion is that paying for sufficiently good science is a prerequisite to taking effective management decisions. Conversely, poor science allows for prevarication that can lead to bad management.
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Acknowledgements |
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Many people are involved in current management of North Sea herring. Without all those who collected the data on the markets and research vessels, assembled the data, and participated in assessments, none of this would have been possible. In particular, I thank Asgeir Aglen who coordinated the collection of international cost data under EU project EASE; Dankert Skagen and Martin Pastoors who provided advice on the development of the current assessment and data weighting; Ken Patterson, Dankert Skagen, Hans Lassen, and Martin Pastoors who did most of the work on the management plan in 1996; and Niels Daan, Mark Dickey-Collas, and Martin Pastoors who provided editorial help at various stages. The work was funded by FRS Marine Laboratory and the EU under the EASE project.
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References |
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TopIntroductionGeneral descriptionComparison of stock projection...Costs and benefits of...ConclusionsReferences |
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Anon. Report of the European project European Fisheries Advisory System Evaluation (EASE). (2007) Brussels: European Commission Directorate-General Fisheries, Rue Joseph II. Contract Number: Q5CA-2002-01693.
Bjoerndal T., Conrad J. M. The dynamics of an open access fishery. Canadian Journal of Economics (1987) 20:74–85.[CrossRef]
Buhl-Mortensen L., Toresen R. Fisheries management in a sea of uncertainty: the role and responsibility of scientists in attaining a precautionary approach. International Journal of Sustainable Development (2001) 4:245–264.[CrossRef]
Christensen S., Lassen H. The economic impact of the ACFM catch options for the Danish North Sea herring and industrial fisheries in 1999. Fisheries Research (2004) 68:21–35.[CrossRef][Web of Science]
ICES. Report of the Herring Assessment Working Group for the Area South of 62°N. (2004) ICES Document CM 2004/ACFM: 18.
Kunzlik P. A., Bailey R. S. Harvesting North Sea herring: results of a stochastic simulation model. (1986) ICES Document CM 1986/H: 9.
Nash R. D. M., Dickey-Collas M. The influence of life history dynamics and environment on the determination of year class strength in North Sea herring (Clupea harengus L.). Fisheries Oceanography (2005) 14:279–291.[CrossRef][Web of Science]
Patterson K. R., Skagen D., Pastoors M., Lassen H. Harvest Control Rules for North Sea herring. (1997) Working Document for the ICES ACFM November Meeting 1997.
Poulsen B. Historical exploitation of North Sea herring stocks–an environmental history of the Dutch herring fisheries, c. 1600–1860. (2006) Centre for Maritime and Regional Studies, Department of History and Civilization, University of Southern Denmark. PhD thesis.
Saville A., Bailey R. S. The assessment and management of the herring stocks in the North Sea and to the west of Scotland. ICES Marine Science Symposia (1980) 177:112–142.
Skagen D. Manual for STPR medium term management simulation program. In: IEU–Norway ad hoc Scientific Working Group on Multi-annual Management Plans for Stocks shared by EU and Norway (2004) fish.jrc.cec.eu.int/fisheries/stecf/eu-norway/reportv16.pdf.
Tracy J. D. Herring wars: the Habsburg Netherlands and the struggle for control of the North Sea, ca. 1520–1560. Sixteenth Century Journal (1993) 24:249–272.[CrossRef][Web of Science]
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