A NOVEL INDEX OF ABUNDANCE OF JUVENILE YELLOWFIN TUNA IN THE ATLANTIC OCEAN DERIVED FROM ECHOSOUNDER BUOYS

The collaboration with the Spanish vessel-owners associations and the buoy-providers companies, has made it possible the recovery of the information recorded by the satellite linked GPS tracking echosounder buoys used by the Spanish tropical tuna purse seiners and associated fleet in the Atlantic since 2010. These instrumental buoys inform fishers remotely in real-time about the accurate geolocation of the FAD and the presence and abundance of fish aggregations underneath them. Apart from its unquestionable impact in the conception of a reliable CPUE index from the tropical purse seine tuna fisheries fishing on FADs, echosounder buoys have also the potential of being a privileged observation platform to evaluate abundances of tunas and accompanying species using catch-independent data. Current echosounder buoys provide a single acoustic value without discriminating species or size composition of the fish underneath the FAD. Therefore, it has been necessary to combine the echosounder buoys data with fishery data, species composition and average size, to obtain a specific indicator. This paper presents a novel index of abundance of juvenile yellowfin tuna in the Atlantic Ocean derived from echosounder buoys for the period 2010-2018

Scientific Advice on the estimation of surplus for Sustainable Fisheries Partnership Agreements.

Scientific advice on the concept of surplus, as defined by the UNCLOS, was provided for three types of Sustainable Fisheries Partnership Agreements (SFPAs): i) Mixed SFPAs in West Africa, ii) Tuna SFPAs and iii) SFPA with Greenland. For Mixed SFPAs in West Africa, methods for surplus computation were defined, including alternatives for cases of data limited stocks. These methods may use as input five parameters that could be obtained from those recent stocks assessments that are representative of the current stock status. Surplus estimates would need to be regularly updated (ideally, yearly), according to every new stock assessments and following the enforcement of a management plan (or, by default, according to a transition scheme towards reaching Fmsy in 2020). In the case of West African transboundary stocks, a theoretical share of the surplus could be calculated using a standard rule based on historical catches within EEZs. The Surplus concept is not applicable for Tuna SFPAs, due to the high migratory character of tuna or tuna-like species, the fact that these stocks are mostly found in areas beyond national jurisdictions, the lack of direct estimates of local abundance and impossibility to calculate the capacity of the coastal States. For the SFPA with Greenland, Surplus is considered as any TAC allocated to Greenland and not utilised by this coastal State

Plan de Implementación Regional para Pesquerías Demersales de las Islas Baleares (Mediterráneo Occidental)

De acuerdo con la Política Pesquera Común (PPC), todos los stocks pesqueros europeos deberían situarse en un estado que les permita producir en base al Rendimiento Máximo Sostenible (RMS) en el año 2020 como tarde. El proyecto Myfish, financiado por el Séptimo Programa Marco de la UE, tuvo como objetivo construir un marco operacional para la implementación del objetivo del RMS como herramienta para la futura gestión de stocks pesqueros europeos. Este informe presenta el Plan de Implementación Regional para pesquerías demersales de las Islas Baleares (Mediterráneo Occidental) desarrollado en el marco de Myfish en estrecha colaboración con los principales stakeholders locales. El estudio pretende ser de utilidad como primer paso hacia el diseño de planes de gestión pesquera en el área de estudio y un ejemplo práctico de la implementación de la PPC en el Mediterráneo

Pla d’Implementació Regional per a Pesqueries Demersals de les Illes Balears (Mediterrani Occidental)

D’acord amb la Política Pesquera Comuna (PPC), tots els stocks de peixos europeus haurien de situarse en l’estat que els permetés produir en base al Rendiment Màxim Sostenible (RMS) a l’any 2020 com a màxim. El projecte Myfish, finançat pel Sèptim Programa Marc de la UE, va tenir com a objectiu construir un marc operacional per a la implementació de l’objectiu RMS com a eina per a la futura gestió d’stocks pesquers europeus. Aquest informe presenta el Pla d’Implementació Regional (PIR) per a pesqueries demersals de les Illes Balears (Mediterrani Occidental) desenvolupat en el marc de Myfish en estreta col.laboració amb els principals stakeholers locals. L’estudi pretén ser d’utilitat com a primera passa cap al disseny de plans de gestió pesquera a l’àrea d’estudi i un exemple pràctic d’implementació de la PPC al Mediterrani

STANDARDIZED BIGEYE TUNA CPUE INDEX OF THE BAITBOAT FISHERY IN DAKAR (2005-2017)

The tuna baitboat fishery in Dakar (Senegal) has been operating permanently in the area off Senegal since the beginning of the 1950s. Details of the activity of this fleet can be found in Fonteneau & Diouf (1994), Hallier & Delgado de la Molina (2000) and, more recently, in several ICCAT documents (e.g., Pascual-Alayón et al., 2017, 2018). The number of vessels peaked at the end of the 1950s with 85-90 baitboats. Vessel productivity increased in the 1980s when a new technique was developed, the associated-school fishing method, whereas the baitboat maintains a permanent association with the tunas it fish. This method was described for the first time by Fonteneau & Diouf (1994). The Dakar-based fleet currently consists of 14 vessels: six Senegalese-flagged, seven Spanish-flagged, and one French-flagged. Annual catches of skipjack, yellowfin and bigeye are around 15,000 mt. In this document we have analysed the data corresponding to the seven Spanish flagged baitboat vessels. The activity of this fleet has traditionally taken place in the coastal areas between 14ºN and 21ºN (Figure 1). Their catch is composed mainly by skipjack and, to a lesser extent, by yellowfin and bigeye. In the last 5 years they represented 84%, 10% and 6% of the total catches, respectively. Over the period analysed in this document (2005-2017) the proportion of bigeye has oscillated without tendency between a maximum of 16% in 2006 and a minimum of 3% in 2013; the proportion of bigeye in the last year of this analysis, 2017, was 10%. The annual average catch of bigeye during this period has been 741.8 MT with a standard deviation of 313.8 MT (Figure 2). The average weight of the three tropical tuna species in the catches of this fleet is around 2-3 kg, 4-10 kg and 6-12 for skipjack, yellowfin and bigeye respectively. They have oscillated around these values without tendency during the last 25 years (Figure 17 of Delgado de Molina, A., et al. 2014). The Tropical Tuna Workplan adopted by the SCRS in 2017 included the update of standardized bigeye CPUE indices until 2017 for the European baitboat fleet operating in Dakar. In this working document we present the analyses carried out with detailed VMS and logbook data from this fleet for the most recent period for which both sources of information were available

Potential consequences of climate change for primary production and fish production in large marine ecosystems

Existing methods to predict the effects of climate change on the biomass and production of marine communities are predicated on modelling the interactions and dynamics of individual species, a very challenging approach when interactions and distributions are changing and little is known about the ecological mechanisms driving the responses of many species. An informative parallel approach is to develop size-based methods. These capture the properties of food webs that describe energy flux and production at a particular size, independent of species' ecology. We couple a physical–biogeochemical model with a dynamic, size-based food web model to predict the future effects of climate change on fish biomass and production in 11 large regional shelf seas, with and without fishing effects. Changes in potential fish production are shown to most strongly mirror changes in phytoplankton production. We project declines of 30–60% in potential fish production across some important areas of tropical shelf and upwelling seas, most notably in the eastern Indo-Pacific, the northern Humboldt and the North Canary Current. Conversely, in some areas of the high latitude shelf seas, the production of pelagic predators was projected to increase by 28–89%

Assessment and management of western Mediterranean small-scale fisheries

Nearly 75% of European fishing vessels belongs to small-scale fisheries (SSF). However, SSF have received little attention compared to industrial fisheries. In the Mediterranean Sea, where the SSF traditionally had a high socio-economic relevance, there is a widespread interest in securing its sustainable exploitation and viability. Here we analyze the SSF from Mallorca (Balearic Islands) using fishery statistics from the last 25 years (1990–2014). Although fleet size declined markedly (−55%), landings remained constant which might be related to different, not mutually exclusive explanations such as a decrease in unreported catches, stagnant and closed market or technological creeping. Multivariate analysis revealed eight different fishing tactics corresponding to the main target species. Aggregated, these eight species accounted for 52% and 71% of SSF landings weight and value, respectively. The fishery of these species is markedly seasonal and the landings of most of them showed important fluctuations but no clear trends. In contrast with the claims of SSF having lower impact on the natural resources than other fisheries, surplus production models revealed a generalized overexploitation of these target stocks, especially for the most high-valued species. Simulations with a bioeconomic model showed that fishing effort reductions of 38% would improve the health of fish stocks while increasing the economic profits to as much as 15% from current profits. If all stocks were kept below their MSY level, the reduction in fishing effort would have to be of 53% from current values. If the economic yield from the fishery was to be maximized (MEY), fishing effort would need to be reduced by 28%. Owing to important quantities of unreported catches in the most high-valued species, output values of the stock status indicators and the bioeconomic modelling should be taken with care beyond tracking trends in the fisheryVersión del editor1,524

A preliminary stock assessment for the shortfin silky shark in the indian ocean using data-limited approaches

Silky shark in the Indian Ocean can be targeted by some semi-industrial, artisanal and recreational fisheries, and is a bycatch of industrial fisheries such as pelagic longlines and purse seines. Currently there are not stock status estimations, but the WPEB has in its workplan a first assessment of this species in 2019. The objective of this paper is to provide preliminary support for that scheduled assessment, namely by providing: 1) a reconstruction of the time series of catches, 2) explore the possibility to standardize CPUEs for the EU pelagic longline fleets, 3) estimate prior for intrinsic population growth rate (r) and 4) test the feasibility to implement a data-limited assessment model (CMSY) and 5) provide a tentative stock status. From the final CMSY model configuration tested, the catches of silky shark in the Indian Ocean exceeded MSY from 1994 onwards. The exploitation rate for 2015 (last year in the model) was predicted to be well above MSY-level (F2015/Fmsy = 2.07). The estimation of current biomass (B2015) was 1.03 of Bmsy, with a considerable margin of uncertainty in the prediction (0.44-1.39), meaning that at present the silky shark stock in the Indian Ocean is subject to overfishing but not yet overfished. A fishing reduction to the levels observed in the late 1990s and early 2000s (around 9,000 t) would likely be sustainable. However, given the current level of uncertainty, the estimated lower 95% confidence limit of MSY (6,400 t) could serve as a more conservative guidance for total allowable catches. Due to the preliminary nature of this work and considerable uncertainty associated with the estimations, management advice is not clear. However, this work it could serve as a starting point to the scheduled 2019 IOTC silky shark assessmen