Study of the growth pattern of juvenile European hake (Merluccius merluccius L.) using whole otoliths and length frequency distributions from commercial catches and groundfish surveys

A review of length distributions of commercial landings from bottom trawls, small gillnetters and groundfish surveys in Galicia has led to a new hypothesis about the individual growth of young hake from the Southern Stock (ICES Divisions VIlle and IXa). According to this new hypothesis, hake grow to about 20 cm in the first year of life and up to 35-40 cm during the second. This is in contrast with the more widespread belief that hake grow to about 15 em and 24 during the first and second years of life respectively. Consequences of the new hypothesis are that landings of hake from trawls and small gillnetters would be mainly composed of 1 year old hake and that they would reach first maturity at age 3. An interpretation of the pattern of otolith rings consistent with this hypothesis is that 6 months after birth a first hyaline ring is formed, probably associated with the change from pelagic to demersal life and that another hyaline zone with opaque rings evbedded in it is formed during the first winter. Although this study refers to hake from the Southern stock, it is possible that these conclusions are applicable also to hake from the Northern stock (ICES Divisions VIIIa,b, Sub-areas VI,VII and IV )

Sardine (Sardina pilchardus Walb.) stock differential distribution by age class in Divisions Vlllc and IXa

A migration pattern of sardine juveniles and spawners is suggested as an explanation of the similarities observed between the stock differential distributions from catch in numbers (1979-1985) and from acoustic estimation (1983-1986), both by age group, in Divisions Vlllc and IXa

Primeros datos sobre la dinámica del «stock» de merluza europea (Merluccius merluccius L.) frente al litoral gallego

Durante la campaña «Merluza NW 74", realizada en aguas gallegas, se extrajeron los otolitos de 272 merluzas, que hicieron posible conseguir una primera aproximación a la clave talla-edad, y al relacionarlos con las capturas de merluza obtenidas durante la campaña, una estimación de la mortalidad total. Los resultados muestran que el parámetro K de la ecuación de V. Bertalanffy estaría comprendido entre 0,069 y 0,O83, Y L∞ entre 143 y 124 cm. La mortalidad de las clases 1+ a II+ sería 0,94, y de la clase III+ en adelante, de 0,6. La alta cifra de mortalidad entre las clases II+ y JII+, y el sesgo a la izquierda de la talla media de la clase II+, demostrarían una emigración hacia fuera de la costa de la merluza mayor de esta clase de edad y de clases posteriores.During "Merluza NW 74" survey, undertaken off Galicia shores in August 1974, otoliths of 272 hakes were collected, that made possible to obtain a first approach to the length-age key ; and, relating these data with hake catches during the survey, a first estímate of total mortality was obtained. Results show that the K value from V. Bertalanffy equation would be between 0,069 and 0,083, and L∞ between 143 and 124 cm. Total rnortality between age classes I+ and II+ would be 0,94, and for classes III+ and older, 0,6. The high mortality figure between I+ and III+ classes, and the skewness to the left in the mean length of this class, woulcl show an emigration offshore for the bigger hake of this age-class and older.Versión del editor

Estudios de cartografía, selectividad y marcado de merluza europea, Merluccius merluccius L., frente al litoral gallego

Versión del editor0,000

Atlas de las flotas de pesca españolas de aguas europeas atlánticas

The European Commission has acknowledged the value of fleet-based management approaches since the 2001 Green Paper on the Common Fisheries Policy (CFP). In the 2009 Green Paper, this was again recognized as a key area of interest for future development of the CFP, in particular setting the technical basis for the recent Data Collection Framework (DCF), which specifies the standard for national fishery sampling programs within a pan-European context. These policy changes require deeper and up to date knowledge about European fleets and fisheries, thus encouraging Member States to undertake scientific projects in order to obtain appropriate fleet segmentations classifying their fishing activities within a hierarchical structure. The work presented in this book is the first comprehensive analysis of the Spanish fleets operating in Atlantic European waters, taking into account both European and national management requirements. This has been possible due to the availability of official logbooks, which provide the broadest perspective on the activity of Spanish fleets in the study area. The only exception to this is small scale fisheries, pursued mainly by vessels of less than 10 m of length and, therefore, not subject to the requirement of keeping logbooks. In order to match better European and Spanish fleet classifications, a new level (“Management Unit”) is proposed here, which is placed between “modalidad”, used in the Spanish regulations, and “métier”, as is defined by the recent DCF. Spanish national waters comprise four fishing grounds, two of which are in the European Atlantic. Nine Management Units have been identified in the Northern Spanish fishing ground: bottom otter trawl (OTB10), bottom pair trawl (PTB10), purse seine (PSN10), set long line (LLS10), set gillnet targeting hake (GNS11), set gillnet targeting anglerfish (GNS12), trolling (LTL11) and bait-boats (LHP11) targeting albacore, and hand line targeting mackerel (LHP12). Two Management Units have been identified in Southern Spanish waters: bottom otter trawl (OTB20) and purse seine (PSN20). In European waters outside Spain, six Management Units have been identified in non-Iberian waters: bottom otter trawl (OTB50), bottom pair trawl (PTB50), set long line (LLS50) and set gillnet (GNS50) by vessels of more than 100 GRT, and set long line (LLS60) and set gillnet (GNS60) by vessels of less than 100 GRT. Finally, one Management Unit using bottom otter trawl has been found to operate in Portuguese waters (OTB70). Unluckily, the analyses made on the logbooks of the Spanish fleet using drifting long line could not be used to categorize this fleet due to the geographical limitations of the logbooks available. After detailed analyses and categorization of the Management Units, the results obtained were used in an exercise to test the usefulness and feasibility of using logbook information to answer some DCF requirements. This revealed that logbooks are an essential tool to deal with bioeconomic challenges posed by the new CFP.Versión del edito

100 años investigando el mar. El IEO en su centenario (1914-2014).

Se trata de un libro que pretende divulgar a la sociedad las principales investigaciones multidisciplinares llevadas a cabo por el Instituto Español de Oceanografía durante su primer siglo de vida, y dar a conocer la historia del organismo, de su Sede Central y de los nueve centros oceanográficos repartidos por los litorales mediterráneo y atlántico, en la península y archipiélagos.Kongsberg 20

An analysis of the historical catches of hake, 1936-1977, in subareas IV, VI, VII and VIII

Changes in the catch level of hake since 1936 to 1977 corresponding to subareas IV, VI, VII and VIII -area of distribution of the northern stock of hake, plus division VIIIc- are described and analysed. Four periods can be defined in relation to the catch level: 1) The wars period, 1936-1944, with catches reduced for the course of the spanish civil war, and the second big war; 2) Post-war period, 1945-47, when the effort recovered suddenly at least the prewar level, with very high catches consisting of a portion of the big standing stock accummulated during the wars period plus the surplus.; 3) 1953-1964, with catches stabilized at a level between 70 and 85000 tons; and 4) 1964-77, with catches between 60 and 70000 tons. The document shows how most of the reduction of the catch happened in divisions lVa+Vla, and atributes this decrease in the catch of hake to the strong increaee in trawl effort on the Northern divisions

Some correlations between CPUE series of hake (Northern Stock)

This document describes results of computing correlations between different CPUE series of hake (Northern Stock). Results show that significant correlations between some series appeared when same lag was allowed between series. Lesconil artisans CPUE (fishing in division VIlla) in year t seems to be correlated to CPUE La Rochelle "artlsans" on the same year, to La Coruña trawlers fishing in subarea VII on year (t+1) and to La Rochelle "hauturiers" fishing in subarea VII on year (t+3) ; these "hauturiers" CPUE is correlated with Lorient trawlers CPUE fishing in divisions IVa + VIa two years later. These correlations allow to become more confident on these CPUE series. However, it is difficult to believe that plots like the one in fig. 7 can prove that there is a direct cause to affect relationship between hake CPUE from "artisans" in subareas VII and VIII and hake CPUE from "hauturiers" fishing in divisions IVa + VIa two years later