Temperature-Driven Growth Variation in a Deep-Sea Fish: The Case of Pagellus bogaraveo (Brünnich, 1768) in the Azores Archipelago

Abstract

The deep ocean ecosystem hosts high biodiversity and plays a critical role for humans through the ecosystem services it provides, such as fisheries and climate regulation. However, high longevity, late reproduction, and low fecundity of many organisms living in the deep ocean make them particularly vulnerable to fishing and climate change. A better understanding of how exploitation and changing environmental conditions affect life-history parameters (e.g., growth) of commercially important fish species is crucial for their long-term sustainable management. To this end, we used otolith increment widths and a mixed-effects modeling approach to develop a 42-year growth chronology (1975–2016) of the commercially important deep-sea fish species blackspot seabream (Pagellus bogaraveo) among the three island groups of the Azores archipelago (Northeast Atlantic). Growth was related to intrinsic (age and age-at-capture) and extrinsic factors (capture location, temperature-at-depth, North Atlantic Oscillation (NAO), Eastern Atlantic Pattern (EAP), and proxy for exploitation (landings)). Over the four decades analyzed, annual growth patterns varied among the three island groups. Overall, temperature-at-depth was the best predictor of growth, with warmer water associated with slower growth, likely reflecting physiological conditions and food availability. Average population growth response to temperature was separated into among-individual variation and within-individual variation. The significant among-individual growth response to temperature was likely related to different individual-specific past experiences. Our results suggested that rising ocean temperature may have important repercussions on growth, and consequently on blackspot seabream fishery production. Identifying drivers of blackspot seabream growth variation can improve our understanding of past and present condition of the populations toward the sustainable management of the fishery.

Intraspecific variability of the saccular and utricular otoliths of the hatchetfish Argyropelecus hemigymnus (Cocco, 1829) from the Strait of Messina (Central Mediterranean Sea)

“…Water masses’ physicochemical differences between geographical areas and genetic differences between population lineages can also induce these differences. For example, the temperature can drive growth and morphological variations in deep-sea fishes, as reported for the black spot sea beam Pagellus bogaraveo , Brünnich, 1768 [ 119 ], while the overall contrasting environmental conditions between different marine areas can influence the overall otoliths morphological and outlines differences, as highlighted for the populations of coral reef snapper Lutjanus kasmira , Forsskål, 1775 from the Pacific Ocean [ 108 ]. Otherwise, genetic variations at the intra-specific level, such as those derived from long-time separation events among populations, only affect otolith locally, mainly in the rostrum and antirostrum parts [ 108 ].…”

Long-term trends in functional diversity of exploited marine fish in the Azores’ archipelago: past and present

“…Although significant efforts have been made to manage fishery resources sustainably in the Azores archipelago, there is a growing concern regarding overfishing, ecosystem degradation, biodiversity loss and the impacts of climate change on fisheries (Morato et al, 2006;Morato et al, 2010;Pham et al, 2014;Abecasis et al, 2015;Neves et al, 2021;Torres et al, 2022). This emphasizes the need for a deeper understanding of the changes occurring in fish communities exploited by Azorean fishing fleet (Pham et al, 2013;Fauconnet et al, 2019;Santos et al, 2019;Medeiros-Leal et al, 2023;Parra et al, 2023).…”