Twenty-five-year longevity of European hake (Merluccius merluccius) from novel use of bomb radiocarbon dating in the Mediterranean Sea

Abstract

Abstract. The high variability of growth and longevity estimates for European hake (Merluccius merluccius) reflects the existence of two opposing hypotheses on growth rates that differ by a factor of 2: (1) a fast-growing hypothesis (FGH) with a maximum age near 15 years; and (2) a slow-growing hypothesis (SGH) with a maximum age near 30 years. A recently established regional radiocarbon ( 14 C) reference led to a first-time application of bomb 14 C dating in the Mediterranean Sea to three of the largest-sized and potentially oldest-catch female European hake. Because age reading of otoliths is very subjective and poorly defined, these fish were aged blind with bomb radiocarbon ( 14 C) dating as an independent estimate of validated age. The validated ages were compared with the theoretical maximum ages from the most reliable FGH and SGH von Bertalanffy growth functions. Among the three bomb 14 C ages, the most diagnostic length-at-age was an alignment with the bomb 14 C rise period for two of the three fish, providing validated ages of 22 years (74.5-cm total length) and 25 years (88-cm total length). The results provide estimates of length-at-age that are in agreement with the SGH and cannot be accounted for by the FGH.

Bomb‐produced radiocarbon in the western tropical Pacific Ocean: Guam coral reveals operation‐specific signals from the Pacific Proving Grounds

“…This observation emphasizes the challenges for use of this kind of record as a reference in determining the age of fishes [ Kalish , ; Andrews et al ., ] and other tropical marine organisms [ Fallon and Guilderson , ; Darrenougue et al ., ; Van Houtan et al ., ] that form conserved hard parts (i.e., otoliths or skeletal structures). Because of its efficacy in providing validated age and growth estimates for marine organisms that require management, bomb 14 C dating using hermatypic corals as a reference has expanded in its application geographically and in its temporal utility [e.g., Cook et al ., ; Andrews et al ., ; Vitale et al ., ]. The aim of the current study was to establish a new Δ 14 C record for Guam—a benchmark for future age and growth studies in the region—using an existing coral core from Guam that was previously analyzed and validated (δ 18 O) as a temporal record for ocean‐climate change [ Asami et al ., ], historical plutonium (Pu) sources [ Lindahl et al ., ], and ocean acidification [ Shinjo et al ., ].…”

Modelling the effects of more selective trawl nets on the productivity of European hake (Merluccius merluccius) and deep-water rose shrimp (Parapenaeus longirostris) stocks in the Strait of Sicily

“…The shifted effect of the grid on hake stock is due to the growth parameters used in the model. According to Vitale et al (2016), HKE in the Strait of Sicily is assumed to follow a slow growth, reaching the first maturity after the second year of life, with a length at first maturity of 21.5-28 cm TL for males and 31-37 cm TL for females.…”

Fish and Sclerochronology Research in the Mediterranean: Challenges and Opportunities for Reconstructing Environmental Changes

“…However, many the most commercially important fish species living in the Mediterranean Sea do not have clearly distinguished growth patterns in their otoliths, which presents a challenge for this type of research. For example, it is still difficult to determine the growth boundaries for the first growth increments in otoliths of Mullus barbatus due slow growth and number of false-growth increments laid down before the annulus (Carbonara et al, 2018) and of Merluccius merluccius due to the fast growth (de Pontual et al, 2003;Piñeiro et al, 2007;Mellon-Duval et al, 2010) and long spawning period of the species (Morales-Nin and Aldebert, 1997) although a number of direct methods to validate age assessment were used, like mark-recapture (de Pontual et al, 2003;Mellon-Duval et al, 2010), first ring appearance (Belcari et al, 2006), or bomb radiocarbon dating (Vitale et al, 2016).…”