The Alarming Decline of Mediterranean Fish Stocks

Abstract

In recent years, fisheries management has succeeded in stabilizing and even improving the state of many global fisheries resources [1-5]. This is particularly evident in areas where stocks are exploited in compliance with scientific advice and strong institutional structures are in place [1, 5]. In Europe, the well-managed northeast (NE) Atlantic fish stocks have been recovering in response to decreasing fishing pressure over the past decade [3-6], albeit with a long way to go for a universal stock rebuild [3, 7]. Meanwhile, little is known about the temporal development of the European Mediterranean stocks, whose management relies on input controls that are often poorly enforced. Here, we perform a meta-analysis of 42 European Mediterranean stocks of nine species in 1990-2010, showing that exploitation rate has been steadily increasing, selectivity (proportional exploitation of juveniles) has been deteriorating, and stocks have been shrinking. We implement species-specific simulation models to quantify changes in exploitation rate and selectivity that would maximize long-term yields and halt stock depletion. We show that stocks would be more resilient to fishing and produce higher long-term yields if harvested a few years after maturation because current selectivity is far from optimal, especially for demersal stocks. The European Common Fisheries Policy that has assisted in improving the state of NE Atlantic fish stocks in the past 10 years has failed to deliver similar results for Mediterranean stocks managed under the same policy. Limiting juvenile exploitation, advancing management plans, and strengthening compliance, control, and enforcement could promote fisheries sustainability in the Mediterranean.

Mediterranean Sea: A Failure of the European Fisheries Management System

“…On the other hand, Mediterranean stocks have largely declined in the last 15 years and their exploitation level has raised or remained above the F MSY level during the same period of time (Vasilakopoulos et al, 2014; this paper). Here we showed that up to 2014, the average exploitation rate for the main demersal and small pelagic stocks of the Mediterranean Sea is around three times the estimated level of F MSY , with a general similar pattern across species and area, which confirms analyses recently conducted (STECF, 2015c).…”

“…In recent years European fisheries managers have witnessed the success of the European CFP in the north (i.e., North East Atlantic, Cardinale et al, 2012;Fernandes and Cook, 2013) and at the same time, its failure in the south (i.e., Mediterranean Sea, Colloca et al, 2013;Vasilakopoulos et al, 2014). Thus, despite the fact that both areas are managed under the same broad fishery policy (i.e., European CFP), a large discrepancy in management performance still occur between the North East Atlantic and the Mediterranean Sea.…”

“…Here we showed that up to 2014, the average exploitation rate for the main demersal and small pelagic stocks of the Mediterranean Sea is around three times the estimated level of F MSY , with a general similar pattern across species and area, which confirms analyses recently conducted (STECF, 2015c). Moreover, as we have mostly only a snapshot of the last decade for Mediterranean stocks (i.e., generally from the beginning of the 2000s to today), and, as F has been estimated to be very high since the beginning of the time series (Colloca et al, 2013;Vasilakopoulos et al, 2014), the decline in stock biomass might have started much before and being more pronounced than described by current assessment models. This has been demonstrated by those assessments with a longer time series, as small pelagics in the Adriatic Sea (time series: 1975GFCM, 2015b) and common sole in the Northern Adriatic Sea (time series: 1970GFCM, 2015a;STECF, 2016).…”

“…After 8 years from the adoption of WSSD and the enforcement of MSFD with the definition of GES and targets in each Member State (MS), and the concurrent application of the CFP, Europe has made great progress toward MSY for stocks inhabiting the North East Atlantic (e.g., Cardinale, 2011;Cardinale et al, 2012;Fernandes and Cook, 2013) but it is still far from achieving its objectives for the Mediterranean Sea marine resources (e.g., Colloca et al, 2013;Vasilakopoulos et al, 2014). Notwithstanding the enforcement of the EU Data Collection Regulation (EU, 2000) in the early 2000s by all EU MSs, and the rapid increase in the number of assessed stocks by the General Fisheries Commission for the Mediterranean (GFCM) and the European Scientific, Technical and Economic Committee for Fisheries (STECF), Mediterranean Sea marine resources are still exploited above the levels that deliver the maximum sustainable yield and no signs of recovery are evident (Vasilakopoulos et al, 2014).…”

“…Notwithstanding the enforcement of the EU Data Collection Regulation (EU, 2000) in the early 2000s by all EU MSs, and the rapid increase in the number of assessed stocks by the General Fisheries Commission for the Mediterranean (GFCM) and the European Scientific, Technical and Economic Committee for Fisheries (STECF), Mediterranean Sea marine resources are still exploited above the levels that deliver the maximum sustainable yield and no signs of recovery are evident (Vasilakopoulos et al, 2014). Particularly, in the Mediterranean Sea, the achievements of WSSD targets is at risk to be further delayed by the management systems currently enforced at the national and EU level.…”