Old Info for a New Fisheries Policy: Discard Ratios and Lengths at Discarding in EU Mediterranean Bottom Trawl Fisheries

Tsagarakis, Konstantinos; Carbonell, Aïna; Brčić, Jure; Bellido, José María; Carbonara, Pierluigi; Casciaro, Loredana; Edridge, A.; Garcı́a, Teresa; González, María Luisa Soriano; Šifner, Svjetlana Krstulović; Machias, Athanassios; Notti, Emilio; Παπαντωνίου, Γεωργία; Sala, Antonello; Škeljo, Frane; Vitale, Sergio; Vassilopoulou, Vassiliki

doi:10.3389/fmars.2017.00099

Cited by 42 publications

(46 citation statements)

References 42 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Although discarding in the Mediterranean has been documented to vary highly across the different GSAs, both among species (Tsagarakis et al, 2017) and among the different fishing gears (Tsagarakis et al, 2014), this study provides evidence that even vessels operating the same gear during different time periods (seasons and years) and spatial locations exhibit quite diverse discarding patterns. This high heterogeneity and spatiotemporal variation in discarding practices make it even more challenging to apply the Landing Obligation because the quantities of catches affected by the regulation cannot be estimated with high accuracy.…”

Section: Discussionmentioning

confidence: 62%

The “discard problem” in Mediterranean fisheries, in the face of the European Union landing obligation: the case of bottom trawl fishery and implications for management

et al. 2018

Self Cite

View full text Add to dashboard Cite

Since the first introduction of the landing obligation (a.k.a. Discard ban) in 2015, the EU Mediterranean fisheries are facing some unforeseen challenges. The demersal bottom trawl fisheries, being the most significant contributors to the so-called 'discard problem', are confronted with the greatest challenges. Data from the Italian and the Greek fleet, spanning over two decades (1995–2015), were analysed with the intention of revealing the diversity and heterogeneity of the discard problem, especially for regulated species. Species composition of discards, as well as discarding rates, were shown to be irregular, fluctuating among areas, depth strata, seasons and years. Although fish dominated the discarded gross catch in weight, benthic invertebrates (other than commercial cephalopods and crustaceans) were the taxa discarded almost exclusively. The established minimum conservation reference size was largely ignored by fishers. From a management point of view, the present investigation suggests that the recently established Discard Management Plans lack scientific evidence (given the high intrinsic variability of the parameters and confusion regarding the rules) and provide exemptions from the landing obligation that will in practice allow the average Mediterranean bottom trawl vessel to continue business as usual. Moreover, detecting if these rules are actually respected is an almost impossible task for the Mediterranean control and enforcement authorities. Incentivizing the adoption of fishing technologies and practices that reduce pre-harvest mortality and post-harvest discards, while avoiding damage to sensitive marine species and habitats, seems the only way to move forward, rather than dealing with the problem after it has occurred.

show abstract

Section: Discussionmentioning

confidence: 62%

The “discard problem” in Mediterranean fisheries, in the face of the European Union landing obligation: the case of bottom trawl fishery and implications for management

et al. 2018

Self Cite

View full text Add to dashboard Cite

show abstract

“…Non‐commercial species as well as species of low commercial value were also categorised as discards. In addition, for certain species such as horse mackerels, Trachurus spp, individuals larger than MCRS were also included in the “discards” fraction as their L 50 (length at which 50% of individuals are discarded) in the area has been found to exceed MCRS (Tsagarakis et al., ).…”

Section: Methodsmentioning

confidence: 99%

“…Over 100 species are totally or partially discarded (Machias et al, 2001;Tsagarakis, Machias, Giannoulaki, Somarakis, & Karakassis, 2008). In addition, landings of some species (e.g., hake, Merluccius merluccius (Linnaeus, 1758)) often include undersized catch (i.e., smaller than the Minimum Conservation Reference Size) due to poor selectivity in the Mediterranean trawl fisheries (e.g., Sala & Lucchetti, 2011) and the existence of market demands for this part of the catch (Machias et al, 2004;Tsagarakis et al, 2017). Trawlers usually operate on the continental shelf with half of the effort distributed on grounds with depths of 50-100 m (Maina, Kavadas, Mantopoulou, & Somarakis, 2014;Maina et al, 2016).…”

mentioning

confidence: 99%

Preliminary assessment of discards survival in a multi-species Mediterranean bottom trawl fishery

et al. 2018

View full text Add to dashboard Cite

Summary The EU Common Fisheries Policy (CFP) reform establishes a gradual landing obligation for stocks for which catch limits are set, and in the Mediterranean for species with Minimum Conservation Reference Size. However, the landing obligation will not apply for species with scientific evidence of high survival rates. Discards estimates usually assume that the whole discarded catch is dead or dies at sea. However, survival of individuals discarded at sea is substantial for several species. In the Mediterranean Sea, the information on this issue is very limited. The aim of this study is to perform a preliminary assessment of the short‐term survival of discards in the multi‐species bottom trawl fishery in the Eastern Ionian Sea, Greece. Experimental fishing was held in spring when no water column stratification was observed and in autumn when a seasonal thermocline was formed. The catch was sorted, the regularly discarded species/sizes were put in tanks and their survival was monitored in specific time intervals up to 72 hr. A seasonal effect was obvious with high mortality in autumn being attributed to high water temperatures. Survival was low or zero for most species, but was relatively high for certain species (e.g., annular seabream, Diplodus annularis (Linnaeus, 1758); European conger, Conger conger (Linnaeus, 1758); brown comber, Serranus hepatus (Linnaeus, 1758) among bony fishes) and broad taxonomic categories (elasmobranchs and most invertebrates) in spring or in both seasons. Poor survival was generally estimated for most species subject to the landing obligation (e.g., hake, Merluccius merluccius (Linnaeus, 1758)). The present study, even though preliminary, can be important for improving future works, for identifying species with high survival potential, and—to a lesser extent—for the implementation of the CFP.

show abstract

“…The specific biological characteristics make an organism more or less vulnerable to different stressors of the capture method and release process (de Juan and Demestre 2012). Other factors affecting the survival of released animals are related to the handling practices during the sorting and release processes and to the environmental conditions during capture, hauling on board and sorting, such as hypoxia and temperature , Giomi et al 2008, Tsagarakis et al 2017.…”

Section: Introductionmentioning

confidence: 99%

Ecological importance of survival of unwanted invertebrates discarded in different NW Mediterranean trawl fisheries

Demestre¹,

Sartor

García-de-Vinuesa³

et al. 2018

Sci. Mar.

View full text Add to dashboard Cite

There is currently very little information on the survival of discards of unwanted and unregulated catches of invertebrates after the stresses caused by capture. A great number of the unregulated invertebrate species form the basis of essential fish habitats for important fisheries resources such as hake, red mullet and cuttlefish. Thus, data on their survival after discarding may help to interpret the role of these species within the benthic ecosystems. Furthermore, descriptor 6 of the Marine Strategy Framework Directive (EU Directive 2008/56/E) foresees maintaining sea floor integrity at a level that ensures that the structure and functions of the ecosystems are safeguarded, and Article 7(d) of the Common Fisheries Policy (EU Reg. 1380/2013) foresees the implementation of management measures for fishing with low impact on the marine ecosystem and fishery resources. Survival measurements by direct recovery of tagged discarded species are not effective in bottom trawl fisheries, for which alternative studies such as semi-quantitative measures obtained on board prior to discarding can be considered as appropriate for mortality estimation. The present work assessed the survival of unwanted species using a semi-quantitative assessment on the deck of trawlers and at the laboratory for a period of 96 hours in two Mediterranean areas (the Catalan coast and the Ligurian and Northern Tyrrhenian seas). A high number of discarded invertebrates showed a high percentage of survival (>70%) in both assessments. The results can be used to provide information that can help to achieve higher survival levels of discarded specimens and enhance the productivity of fishing grounds by increasing the health of benthic ecosystems.

show abstract

Old Info for a New Fisheries Policy: Discard Ratios and Lengths at Discarding in EU Mediterranean Bottom Trawl Fisheries

Cited by 42 publications

References 42 publications

The “discard problem” in Mediterranean fisheries, in the face of the European Union landing obligation: the case of bottom trawl fishery and implications for management

The “discard problem” in Mediterranean fisheries, in the face of the European Union landing obligation: the case of bottom trawl fishery and implications for management

Preliminary assessment of discards survival in a multi-species Mediterranean bottom trawl fishery

Ecological importance of survival of unwanted invertebrates discarded in different NW Mediterranean trawl fisheries

Contact Info

Product

Resources

About