The Irish Sea: Is it eutrophic?

The question of whether the Irish Sea is eutrophic is addressed by reviewing the evidence for anthropogenic nutrient enrichment, elevated phytoplankton production and biomass and undesirable disturbance in the context of the EU and OSPAR definitions of eutrophication. Winter concentrations of dissolved available inorganic phosphate (DAIP), nitrogen (DAIN as nitrate and nitrite) and silicate (Si) in coastal waters and concentrations of DAIP and Si in offshore waters of the Irish Sea are elevated relative to winter Celtic Sea shelf break concentrations (0.5 μM DAIP, 7.7 μM DAIN and 2.7 μM Si). Significant, negative nutrient salinity relationships and analysis of the Isle of Man nutrient time-series indicate that the elevated Irish Sea levels of DAIP and DAIN are the result of anthropogenic enrichment with highest concentrations (≈2.0 μM DAIP, 30 μM DAIN and 17 μM Si) measured in near shore eastern Irish Sea waters.     

Compromise in the IWC: Is it possible or desirable?

It is widely assumed that a compromise position must be reached between pro- and anti-whaling groupings within the International Whaling Commission. This assumption is based on the belief that the Commission will collapse in the absence of any such compromise, and has been the driving force behind a number of compromise proposals in recent years. This paper argues that the fundamental positions of the two groups are so different, and that both groups are getting enough from the current position as to make it unattractive to either group to make any serious concessions toward a compromise position.The suggested solution is for the two groups to “agree to disagree”; using the resulting improvement in goodwill between them to focus on cooperation on those aspects of whale conservation on which they can agree.     

Rights based fishing on the high seas: Is it possible?

The high seas fisheries are troubled by overcapacity and lax enforcement of management rules. The idea has emerged that these problems could be dealt with by property rights solutions such as ITQs. Such management tools only emerged after the 200-mile EEZ was established. This made it possible to apply the sovereign state's legislative, enforcement and judiciary apparatus to regulate fisheries. It is argued that without the EEZ such solutions would have been unlikely to emerge, and that a further extension of the EEZ is necessary to apply rights-based regulations to high seas fisheries. The current management regime of high seas fisheries lacks the necessary enforcement apparatus, which makes it necessary to apply trade sanctions, port measures and blacklisting to support regulations of high seas fisheries. It is argued that such measures are likely to be the second best, compared to further extending coastal state jurisdiction. Finally a bioeconomic model is applied to analyze potential gains from cooperation in high seas fisheries.     

The requirement to rebuild US fish stocks: Is it working?

The Magnuson–Stevens Fishery Conservation and Management Act (MSA) was amended in 1996 to require that overfished stocks be rebuilt in as short a time period as possible, not to exceed 10 years, with limited exceptions. This comment examines the basic but important question of whether the implementation of rebuilding plans under the 1996 amendments has in fact been associated with biomass recovery. Specifically, for each of the 44 stocks examined, this analysis compares the biomass trend before rebuilding plan implementation to the trend after rebuilding plan implementation using a linear trend-break model. The analysis demonstrates a statistically significant positive association between the implementation of rebuilding plans and standardized biomass in 19 of 44 stocks. None of the 44 stocks examined showed a statistically significant negative association. The analysis showed a strong temporal relationship between the implementation of the policy and rebounds in fish stocks.     

Can the United States have its fish and eat it too?

As domestic affluence increases, nations advocate for conservation policies to protect domestic biodiversity that often curtail natural resource production activities such as fishing. If concomitant consumption patterns remain unchanged, environmentally conscious nations with high consumption rates such as the U.S. may only be distancing themselves from the negative environmental impacts associated with consuming resources and commodities produced elsewhere. This unintended displacement of ecosystem impacts, or leakage, associated with conservation policies has not been studied extensively in marine fisheries. This paper examines this topic, drawing on case studies to illustrate the ways in which unilateral marine conservation actions can shift ecosystem impacts elsewhere, as has been documented in land use interventions. The authors argue that the U.S. should recognize these distant ecological consequences and move toward greater self-sufficiency to protect its seafood security and minimize leakage as well as undertake efforts to reduce ecosystem impacts of foreign fisheries on which it relies. Six solutions are suggested for broadening the marine conservation and seafood consumption discussion to address leakage induced by U.S. policy.     

Benguela upwelling: how does it affect South Africa's conservation philosophy?

South African and international conservation perceptions are outlined, specifically for marine systems. The concept of Marine Protected Areas is stressed and future plans sketched out.     

The LUSI mud volcano triggering controversy: Was it caused by drilling?

Following the Yogyakarta earthquake on May 27th, 2006, the subsequent eruption of a mud volcano has been closely observed and analyzed by the geological community. The mud volcano, known as LUSI, began erupting near the Banjarpanji-1 exploration well in Sidoarjo, East Java, Indonesia. LUSI offers a unique opportunity to study the genesis and development of a mud volcano.     

Eco-labeling of seafood: Does it affect the harvesting patterns of Norwegian fishermen?

The aim of this paper is to compare the criteria for eco-labeling of wild-caught fish in the Norwegian eco-certified fisheries, and to study if these eco-labels affect the harvesting patterns of Norwegian fishermen. The eco-labels Marine Stewardship Council (MSC), KRAV and Friend of the Sea (FOS) as applied in 2009 were studied. In this study, the harvesting patterns are defined by using the following parameters: season, catch area, size of fishing vessel, gear type, bycatch, location of landing site and distance to the fishing ground. KRAV had more specific criteria than did MSC and FOS in specific fisheries regarding time of the fishing effort, catch area, size of fishing vessels, gear type (e.g. hook size, and the use of beam trawlers was not permitted) and distance to the fishing ground. The findings show that few of the eco-label requirements influenced these aspects in Norwegian fisheries.     

Sea-ice retreat in the Sea of Okhotsk and the ice–ocean albedo feedback effect on it

Sea-ice retreat processes are examined in the Sea of Okhotsk. A heat budget analysis in the sea-ice zone shows that net heat flux from the atmosphere at the water surface is about 77 W m⁻² on average in the active ice melt season (April) due to large solar heating, while that at the ice surface is about 12 W m⁻² because of the difference in surface albedo. The temporal variation of the heat input into the upper ocean through the open water fraction corresponds well to that of the latent heat required for ice retreat. These results suggest that heat input into the ice–upper ocean system from the atmosphere mainly occurs at the open water fraction, and this heat input into the upper ocean is an important heat source for ice melting. The decrease in ice area in the active melt season (April) and the geostrophic wind just before the melt season (March) show a correlation: the decrease is large when the offshoreward wind is strong. This relationship can be explained by the following process. Once ice concentration is decreased (increased) by the offshoreward (onshoreward) wind just before the melt season, solar heating of the upper ocean through the increased (decreased) open water fraction is enhanced (reduced), leading to (suppressing) a further decrease in ice concentration. This positive feedback is regarded as the ice–ocean albedo feedback, and explains in part the large interannual variability of the ice cover in the ice melt season.     

Adaptive management of declining fisheries: When is it worth trying to rebuild stocks through fishery regulation?

Declining catches are typically taken to be a warning sign of overfishing. But in fact, many such declines have been driven by recruitment changes unrelated to stock size, as evidenced by the failure of stocks to recover after reduction in fishing or recovery despite the failure to reduce fishing. Given a declining pattern, supposedly precautionary decisions to reduce fishing should be treated as experimental management options with a high probability of not resulting in the desired recovery to more productive stock sizes. Simple decision tables can be used to compare such experimental options to “wait and see” options that do not involve fishing reductions. A case example with a grouper fishery in Kuwait demonstrates that experimental effort reduction may not be the best policy from a decision analysis perspective, at least when there are substantial reasons to expect recruitment changes unrelated to stock size. In this case, virtual population analysis and stock reduction analysis models indicate either unusually weak recruitment compensation (steepness h < 0.4) or progressive decline in recruitment carrying capacity, possibly caused by decreases in estuarine rearing habitat associated with declining flows of the Tigris and Euphrates Rivers.     

The Manila clam population in Arcachon Bay (SW France): Can it be kept sustainable?

The venerid clam Ruditapes philippinarum is the most prominent suspension-feeding bivalve inhabiting muddy intertidal seagrass beds in Arcachon Bay (SW France). It is exploited by fishermen, and Arcachon Bay ranks number one in France in terms of production and total biomass of this species. Previous studies revealed a decrease in the standing stock of R. philippinarum since 2003 and unbalanced length–frequency distributions with a lack of juveniles and of adults > 40 mm. Consequently, the population dynamics of this bivalve were studied at four intertidal sites and one oceanic site in Arcachon Bay. As clam size structure did not allow classical dynamics computations, field monitoring was coupled with field experiments (tagging–recapture) over two years. Monitoring of condition index and gonadal maturation stages highlighted a high variability in spawning number and intensity between sites. Recruitment events in the exploited area varied spatially but with uniformly low values. Von Bertalanffy Growth Function (VBGF) parameters (K, L_∞) were determined using Appeldoorn and ELEFAN methods. In the exploited sites in the inner lagoon, K was relatively high (mean = 0.72 yr^? 1) but L_∞ was low (mean = 41.1 mm) resulting in a moderate growth performance index (Φ′ = 2.99). Growth parameters were not correlated with immersion time and L_∞ was different between sites. Comparison of mortality coefficients (Z) between cage experiments and field monitoring suggested that fishing accounts for 65–75% of total adult mortality. Low recruitment, a low growth rate and a normal mortality rate led to low somatic production (4.1 and 8.7 g Shell-Free Dry Weight (SFDW) m^? 2 yr^? 1) and an annual P/B ratio from 0.44 to 0.92 yr^? 1. Under current conditions, the possibility of a sustainable population in Arcachon Bay will strongly depend on recruitment success and fishing management.     

“Those who cannot remember the past are condemned to repeat it”: comparing fisheries reforms in South Africa

The paper argues that the reduction of history to “apartheid” has hamstrung efforts to reform the South African fisheries since 1994, by privileging race over class and state. The salience of the latter in the maintenance and reproduction of endemic inequality is demonstrated by a comparison of the current reform process with that in the 1940s. This reveals a series of striking similarities and shows how the initial redistribution agenda in both instances was subverted in favour of a consolidation of monopoly capital and state control over the marine commons.     

From low- to high-value fisheries: Is it possible to quantify the trade-off between management cost,risk and catch?

Fishery managers are faced with the challenge of maintaining sustainable fisheries at the lowest possible cost while conforming to international and national obligations. Given that fisheries range from low to high value, there is a real need to understand how to trade ecological and economic risks, and the various costs associated with their management, against the benefits from catch. Key to this is an understanding of (a) the costs corresponding to a given level of acceptable risk, or conversely, (b) the change in risk given a change in cost investment. This paper first defines biological, economic and ecosystem risk at a whole-of-fishery level, and then develops a simple model to quantify the trade-offs between risk, cost and catch. Using as case studies Australia's federally managed fisheries that range from data-rich to data-poor, risk was quantified for target species in terms of both their limit and target reference points (defined as “biological risk” and “economic risk”, respectively), and for ecosystems in terms of overall ecological impact (defined as “ecosystem risk”). A statistical linear model was used to quantify the risk–cost–catch frontier for each of the three forms of risk. The most parsimonious models were statistically significant for each. However, the management and research costs were mostly positively correlated with risk, indicating that these tended to be reactive to risk, as opposed to risk decreasing in response to increased costs. The only model where this was not the case was for the ecosystem risk, which is probably because these risks have only recently been assessed and the management response to these risks across all the fisheries has so far been limited. For target species risks, it was not possible to develop a model for proactive use. However, the method itself has merit and, if the costs were defined to a greater level of resolution, and/or a time-dynamic modelling approach considered, these issues could potentially be addressed.     

Is a stock overfished if it is depleted by overfishing? A response to the rebuttal of Agnew et al. to Froese and Proelss “Evaluation and legal assessment of certified seafood”

This contribution is a response to the rebuttal of Agnew et al. (2012) to Froese and Proelss (2012) “Evaluation and legal assessment of certified seafood”. It corrects some factually wrong statements in the rebuttal, revisits the definitions of ‘depleted’ and ‘overfished’, and notes that the rebuttal agrees with the international definition of ‘overfishing’ (F>FMSY) that was used by Froese and Proelss (2012). The rebuttal presents an analysis of 45 MSC-certified stocks. Of these, 27% are ‘depleted’ (according to the definition used by MSC) or ‘overfished’ (according to the definition used by Froese and Proelss 2012) and 16% are subject to ‘overfishing’, basically confirming the critique of Froese and Proelss (2012). This response concludes that MSC has to change its rules for certification such that (1) overfishing is not allowed and (2) ‘depleted’ stocks are marked as such.