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

2021 ◽  
Vol 8 ◽  
Author(s):  
João Neves ◽  
Eva Giacomello ◽  
Gui M. Menezes ◽  
Jorge Fontes ◽  
Susanne E. Tanner

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.

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Randal A. Singer ◽  
Jon A. Moore ◽  
Edward L. Stanley

Abstract The deep ocean is frequently assumed to be a homogeneous system lacking the same diverse life history strategies found in shallower waters. However, as our methods for exploring the deep ocean improve, common assumptions about dispersal, reproduction and behavior are constantly being challenged. Fishes exhibit the most diverse reproductive strategies among vertebrates. Understanding life history strategies in deep-sea environments is lacking for many species of fishes. Here, we report a novel reproductive strategy where a fish (Parazen pacificus) provides parental care via mouth brooding. This behavior is observed from a specimen collected with eggs present in the buccal cavity, along with other specimens exhibiting pre-brooding morphologies. This is the first description of this unique life history trait in a deep-sea fish and fills in a gap in the larval literature for this family of fishes and prompts further investigation into other novel reproductive modes of deep-sea fauna.


2004 ◽  
Vol 19 (3) ◽  
pp. 299-316 ◽  
Author(s):  
Michael Lodge

AbstractIn light of new scientific discoveries and technological developments in the deep ocean, there is broad concern over the ability of the present system of international governance to deliver sustainable management. This article seeks to identify key objectives for the current international debate. These include: (i) bringing currently unregulated high seas fisheries under international management as soon as possible; (ii) developing a mechanism for the conservation of high seas biodiversity, including appropriate regulation of activities related to marine bioprospecting, and (iii) promoting ocean exploration for the benefit of mankind as a whole. It further suggests some practical ways in which existing governance mechanisms might be used and adapted in the short-term specifically in order to improve the management of deep-sea fisheries on the high seas and to accommodate new and developing uses of the deepocean environment.


2019 ◽  
Vol 6 (8) ◽  
pp. 191164 ◽  
Author(s):  
Craig R. McClain ◽  
Clifton Nunnally ◽  
Mark C. Benfield

The Deepwater Horizon spill is one of the largest environmental disasters with extensive impacts on the economic and ecological health of the Gulf of Mexico. Surface oil and coastal impacts received considerable attention, but the far larger oil spill in the deep ocean and its effects received considerably less examination. Based on 2017 ROV surveys within 500 m of the wellhead, we provide evidence of continued impacts on diversity, abundance and health of deep-sea megafauna. At locations proximal to the wellhead, megafaunal communities are more homogeneous than in unimpacted areas, lacking many taxonomic groups, and driven by high densities of arthropods. Degraded hydrocarbons at the site may be attracting arthropods. The scope of impacts may extend beyond the impacted sites with the potential for impacts to pelagic food webs and commercially important species. Overall, deep-sea ecosystem health, 7 years post spill, is recovering slowly and lingering effects may be extreme.


Author(s):  
E. J. Denton ◽  
F. J. Warren

Measurements were made on the intact retinae dissected from freshly caught deep-sea fish. The unbleached retinae of such fish are not rose-pink like the retinae of most coastal fish or purple like the retinae of most freshwater fish, but are golden in colour.The golden colours are of photosensitive pigments which give retinal absorption curves similar in shape to frog's rhodopsin, but with maxima of absorption displaced on the average about 15 mμ. towards the blue end of the spectrum. The names ‘chrysopsins’ or visual golds are suggested for this group of pigments.The density of such photosensitive pigments is often very high. Retinal density changes on bleaching of more than 1.0 has been found for several deepsea fish. These probably correspond to absolute retinal densities of pigment of about 1.3, i.e. the absorption of 95% of blue-green light striking the retina.The conger and silver freshwater eels have retinae containing similar golden-coloured pigments. These eels begin their lives in the deep ocean and return there when mature to spawn.The significance of this type of photosensitive pigment in the vision of deep-sea fish is discussed, and an estimate is made of the depths at which deepsea fish will see daylight.


2018 ◽  
Vol 592 ◽  
pp. 225-242 ◽  
Author(s):  
E Cruz-Acevedo ◽  
N Tolimieri ◽  
H Aguirre-Villaseñor

Biology ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 522
Author(s):  
Régis Santos ◽  
Wendell Medeiros-Leal ◽  
Osman Crespo ◽  
Ana Novoa-Pabon ◽  
Mário Pinho

With the commercial fishery expansion to deeper waters, some vulnerable deep-sea species have been increasingly captured. To reduce the fishing impacts on these species, exploitation and management must be based on detailed and precise information about their biology. The common mora Mora moro has become the main deep-sea species caught by longliners in the Northeast Atlantic at depths between 600 and 1200 m. In the Azores, landings have more than doubled from the early 2000s to recent years. Despite its growing importance, its life history and population structure are poorly understood, and the current stock status has not been assessed. To better determine its distribution, biology, and long-term changes in abundance and size composition, this study analyzed a fishery-dependent and survey time series from the Azores. M. moro was found on mud and rock bottoms at depths below 300 m. A larger–deeper trend was observed, and females were larger and more abundant than males. The reproductive season took place from August to February. Abundance indices and mean sizes in the catch were marked by changes in fishing fleet operational behavior. M. moro is considered vulnerable to overfishing because it exhibits a long life span, a large size, slow growth, and a low natural mortality.


Author(s):  
G. Diez ◽  
L. Arregi ◽  
M. Basterretxea ◽  
E. Cuende ◽  
I. Oyarzabal

Abstract The changes in abundance and biodiversity of deep-sea fish fauna are described based on an annual deep-water longline survey with data collected during the period 2015–2019 in the Basque Country continental Slope (ICES Division 8c). The sampling scheme included hauls in four 400 m strata, from 650–2250 m deep. The DST sensors installed in the main line have allowed us to set an accurate soak time for each haul, and they were used to calculate fishing effort and CPUE by haul. The catchability of the fishing gear indicated that 15% of the total hooks deployed in the five-year period were able to fish, and that the bottom longline was very effective in fishing a wide number of different species in all depth ranges. The fishing gear caught 14 different species of sharks (13 deepwater and one pelagic), two chimaeras and nine teleosts. The abundance and biomass registered on the hooks attached to the bottom were between three and four times higher than in the floating sections, and the highest CPUE and biomass were recorded between 1051–1450 m, from 2015 to 2017, and in the 1451–1850 m strata, but they do not show any clear trend throughout the five years of the series.


Author(s):  
Fabio C. De Leo ◽  
Jeffrey C. Drazen ◽  
Eric W. Vetter ◽  
Ashley A. Rowden ◽  
Craig R. Smith

Author(s):  
Phillip J Turner ◽  
Matthew Gianni ◽  
Ellen Kenchington ◽  
Sebastian Valanko ◽  
David E Johnson

Abstract The European Union’s deep-sea fisheries regulations (Regulation (EU) No. 2016/2336) established obligations to manage deep-sea fisheries and to protect vulnerable marine ecosystems (VMEs). The European Commission is scheduled to complete a review of the regulations in 2021, providing an opportunity for new scientific information to be incorporated into the implementation of the regulations. Here, we summarise research outputs from the EU-funded Horizon 2020 ATLAS Project and explain their relevance to the regulation of deep-sea fisheries in EU waters. ATLAS research has increased our understanding of the distribution of VMEs and their importance in terms of ecosystem functioning. ATLAS research has also highlighted the utility of molecular techniques to understand fish population structure and the potential for habitat suitability models to help incorporate climate change into decision-making. Building on these scientific advances, we provide recommendations to help increase the effectiveness of management measures to conserve deep-sea fish stocks and protect VMEs.


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