A new approach to recruitment overfishing diagnosis based on fish condition from survey data

Other titles Una nueva aproximación al diagnóstico de la sobrepesca de reclutamiento basada en la condición de los recursos a partir de datos de campaña
Type Article
Date 2019-12
Language English
Author(s) Ordines Francesc1, Lloret Josep2, Tugores Pilar1, Manfredi Chiara3, Guijarro Beatriz1, Jadaud Angelique4, Porcu Cristina5, Gil De Sola Luis6, Carlucci Roberto7, Sartini Marina8, Isajlovic Igor9, Massutti Enric1
Affiliation(s) 1 : Instituto Español de Oceanografía, Centre Oceanogràfic de les Balears, Palma, 07015 Illes Balears, Spain
2 : Universitat de Girona, Campus Montilivi, 17003 Girona, Spain
3 : Università di Bologna, 40126 Bologna, Italy.
4 : IFREMER, Laboratoire Halieutique Mediterranée, 34203 Sète, France
5 : Department of Life and Environmental Sciences, University of Cagliari, Via T. Fiorelli 1, Italy.
6 : Instituto Español de Oceanografía, Centro Oceanográfico de Málaga, 29016 Fuengirola, Málaga, Spain.
7 : Università degli studi di Bari Aldo Moro, 70121 Bari, Italy
8 : Aplysia Soc. Coop. r.l., Livorno, Italy
9 : Institute of Oceanography and Fisheries, 21000 Split, Croatia.
Source Scientia Marina (0214-8358) (Institut de Ciències del Mar de Barcelona, CSIC), 2019-12 , Vol. 83 , N. S1 , P. 223-233
DOI 10.3989/scimar.04950.03A
WOS© Times Cited 2
Note Mediterranean demersal resources and ecosystems: 25 years of MEDITS trawl surveys M.T. Spedicato, G. Tserpes, B. Mérigot and E. Massutí (eds)
Keyword(s) Merluccius merluccius, fishery, recruits, condition index, recruitment overfishing, MEDITS survey
Abstract

A new approach to recruitment overfishing diagnosis is presented. We hypothesize that condition of recruits should increase when recruitment failures are caused by fishing activity. This would be a consequence of the increase in trophic resource availability, because the population is smaller than that which the ecosystem could support. Temporal series of hake recruit condition were calculated from MEDITS survey data collected in Mediterranean geographical sub-areas (GSAs) 1, 6, 17 and 19 from 1994 to 2015. Multiple linear regressions were used to analyse the relationship between mean annual condition and abundance of recruits and climatic indices in each GSA. Significant correlations were only detected in GSA 6, where 69% of condition variability was explained by the negative correlation with recruit abundance, and with two climatic indices, the Western Mediterranean Oscillation and the standardized air temperature anomaly at surface from the Gulf of Lions. Despite the differences in recruit abundance among GSAs, their mean annual condition oscillated around the same basal value during most of the time series, pointing to density-dependent mortality rates as an important mechanism stabilizing hake recruitment to levels close to the carrying capacity when populations do not suffer recruitment overfishing. This pattern changed when the decreasing recruit abundance trend drove GSA 6 condition values persistently above those of the rest of the GSAs. According to our hypothesis, hake in GSA 6 is in recruitment overfishing.

Abstract <p>Este trabajo presenta una nueva aproximaci&oacute;n al diagn&oacute;stico de la sobrepesca de reclutamiento. Nuestra hip&oacute;tesis consiste en que la condici&oacute;n de los reclutas debe aumentar cuando suceden fallos en el reclutamiento debidos a la actividad pesquera. Esto ser&iacute;a una consecuencia del incremento en la disponibilidad de recursos tr&oacute;ficos debido a que la poblaci&oacute;n es m&aacute;s reducida que la que el ecosistema podr&iacute;a soportar. Se calcularon series temporales de condici&oacute;n de reclutas de merluza a partir de datos recogidos en las campa&ntilde;as MEDITS en las sub-&aacute;reas geogr&aacute;ficas (GSAs) 1, 6, 17 y 19 entre los a&ntilde;os 1994 y 2015. Se utiliz&oacute; la regresi&oacute;n lineal m&uacute;ltiple para analizar la relaci&oacute;n entre la condici&oacute;n media anual y la abundancia de reclutas e &iacute;ndices clim&aacute;ticos en cada GSA. Solo se detectaron correlaciones significativas en la GSA 6, d&oacute;nde el 69% de la variabilidad en la condici&oacute;n se explica por la correlaci&oacute;n negativa con la abundancia de reclutas, y con dos &iacute;ndices clim&aacute;ticos, la Oscilaci&oacute;n del Mediterr&aacute;neo Occidental y la anomal&iacute;a estandarizada de la temperatura del aire en superficie en el Golfo de Le&oacute;n. A pesar de las diferencias en la abundancia de reclutas entre GSAs, su condici&oacute;n anual media oscil&oacute; alrededor de un mismo valor basal durante la mayor parte de la serie temporal, sugiriendo que las tasas de mortalidad denso-dependiente son un mecanismo importante para la estabilizaci&oacute;n del reclutamiento de merluza en niveles pr&oacute;ximos a la capacidad de carga cuando las poblaciones no sufren sobrepesca de reclutamiento. Este patr&oacute;n cambi&oacute; cuando la tendencia decreciente de la abundancia de reclutas elev&oacute; los valores de condici&oacute;n en la GSA 6 por encima de los del resto de GSAs de forma persistente. De acuerdo con nuestra hip&oacute;tesis, la merluza de la GSA 6 se encuentra en sobrepesca de reclutamiento.</p>
Full Text
File Pages Size Access
Publisher's official version 11 2 MB Open access
Top of the page

How to cite 

Ordines Francesc, Lloret Josep, Tugores Pilar, Manfredi Chiara, Guijarro Beatriz, Jadaud Angelique, Porcu Cristina, Gil De Sola Luis, Carlucci Roberto, Sartini Marina, Isajlovic Igor, Massutti Enric (2019). A new approach to recruitment overfishing diagnosis based on fish condition from survey data. Scientia Marina, 83(S1), 223-233. Publisher's official version : https://doi.org/10.3989/scimar.04950.03A , Open Access version : https://archimer.ifremer.fr/doc/00513/62458/