Decline in Size-at-Maturity of European Hake in Relation to Environmental Regimes: A Case in the Eastern Ionian Sea
by
, , , and
Aglaia Legaki
1,*,†,
Archontia Chatzispyrou
1,*,†,
Dimitrios Damalas
2,†,
Vasiliki Sgardeli
2,
Evgenia Lefkaditou
1
,
Aikaterini Anastasopoulou
1,
Aikaterini Dogrammatzi
1,
Konstantinos Charalampous
1,
Caterina Stamouli
1,
Vassiliki Vassilopoulou
1,
George Tserpes
2 and
Chryssi Mytilineou
1 1
Hellenic Centre for Marine Research, Institute of Marine Biological Resources and Inland Waters, 16452 Athens, Greece
2
Hellenic Centre for Marine Research, Institute of Marine Biological Resources and Inland Waters, P.O. Box 2214, 71003 Heraklion, Greece
*
Authors to whom correspondence should be addressed.
†
These authors contributed equally to this work.
Animals 2024, 14(1), 61; https://doi.org/10.3390/ani14010061
Submission received: 26 October 2023
/
Revised: 8 December 2023
/
Accepted: 13 December 2023
/
Published: 23 December 2023
(This article belongs to the Special Issue Sexual Maturation and Spawning in Fish)
Simple Summary
The European hake is under fishing pressure, both in the Atlantic and the Mediterranean waters. Moreover, in certain geographic locations, its size-at-maturity has been reported to decline over time. Understanding biological processes in marine life can assist in species stock evaluation and future management, allowing for the avoidance of population decline and diversity loss. This work focuses on exploring the variation in European hake size-at-maturity in the eastern Ionian Sea (Central Mediterranean) during the last five decades, investigating, at the same time, its relationship with environmental change.
Abstract
European hake, Merluccius merluccius L. 1758, is a highly valuable demersal fish species exploited in both the east Atlantic and the Mediterranean Sea. Changes in the size-at-maturity of this species have been reported in various geographic areas. Size-at-maturity is a key parameter in fishery management. Our main goal was to study the trend of the size-at-maturity of European hake in the eastern Ionian Sea (Central Mediterranean) over the last five decades. Utilizing a multi-decadal series of data for various environmental variables, we employed multivariate analyses and non-additive modeling in an attempt to identify shifts in the climatic environment of the eastern Ionian Sea and whether the maturation of the hake population could be affected by these changes. The analyses used suggest a plausible environmental regime shift in the study area in the late 1990s/early 2000s. The decrease in size-at-maturity that was detected in the last two decades may, thus, be associated with environmental changes. However, as many fish stocks already experience fishery-induced evolution, further investigation is necessary to determine whether this environmental effect is an additional stressor on a possibly already fishery-impacted population. The outcomes of this study highlight the importance of investigating the relationship between fish reproductive traits and altered environmental conditions, as the latter are generally ignored during assessments, affecting the robustness of fishery management.
