Evidence for egg brooding and parental care in icefish and other notothenioids in the Southern Ocean

2006 ◽  
Vol 18 (2) ◽  
pp. 223-227 ◽  
Author(s):  
K.-H. Kock ◽  
L.K. Pshenichnov ◽  
A.L. Devries
Keyword(s):  
Southern Ocean ◽  
Parental Care ◽  
Incubation Period ◽  
Fish Species ◽  
Ross Sea ◽  
Antarctic Fish ◽  
Size And Shape ◽  
Relative Fecundity ◽  
Egg Carrying ◽  
Egg Brooding

One of the least known Antarctic fish species is the icefish Chionobathyscus dewitti described first in 1978. Some of its reproductive characteristics appear to be similar to other channichthyids of similar size and shape. Females close to spawning have gonado–somatic indices (GSIs) of more than 20, and absolute fecundity was 2967 to 15612 oocytes in females 33–62 cm long. Relative fecundity was 7.6 in one female. Spawning has been observed in the Ross Sea at 1300 to 1500 m depth from January to March. Chionobathyscus dewitti may exhibit a remarkable egg carrying behaviour: eggs stick together in batches around the pelvic fins of females. The comparatively large number of mature males observed with no indication of an egg batch attached to their ventral fins makes it unlikely that males are involved in egg carrying. The few larvae of C. dewitti caught so far occurred from October onwards. Their size indicates that they have hatched as early as September. This suggests an incubation period of at least six months. We compare this with parental care reported in other notothenioids.

scholarly journals Productivity and Change in Fish and Squid in the Southern Ocean

2021 ◽  
Vol 9 ◽  
Author(s):  
Jilda Alicia Caccavo ◽  
Henrik Christiansen ◽  
Andrew J. Constable ◽  
Laura Ghigliotti ◽  
Rowan Trebilco ◽  
...  
Keyword(s):  
Climate Change ◽  
Southern Ocean ◽  
Life Histories ◽  
Ross Sea ◽  
Global Climate ◽  
Management Strategies ◽  
Antarctic Fish ◽  
Ecosystem Approach ◽  
Ecosystem Structure ◽  
Global Drivers

Southern Ocean ecosystems are globally important and vulnerable to global drivers of change, yet they remain challenging to study. Fish and squid make up a significant portion of the biomass within the Southern Ocean, filling key roles in food webs from forage to mid-trophic species and top predators. They comprise a diverse array of species uniquely adapted to the extreme habitats of the region. Adaptations such as antifreeze glycoproteins, lipid-retention, extended larval phases, delayed senescence, and energy-conserving life strategies equip Antarctic fish and squid to withstand the dark winters and yearlong subzero temperatures experienced in much of the Southern Ocean. In addition to krill exploitation, the comparatively high commercial value of Antarctic fish, particularly the lucrative toothfish, drives fisheries interests, which has included illegal fishing. Uncertainty about the population dynamics of target species and ecosystem structure and function more broadly has necessitated a precautionary, ecosystem approach to managing these stocks and enabling the recovery of depleted species. Fisheries currently remain the major local driver of change in Southern Ocean fish productivity, but global climate change presents an even greater challenge to assessing future changes. Parts of the Southern Ocean are experiencing ocean-warming, such as the West Antarctic Peninsula, while other areas, such as the Ross Sea shelf, have undergone cooling in recent years. These trends are expected to result in a redistribution of species based on their tolerances to different temperature regimes. Climate variability may impair the migratory response of these species to environmental change, while imposing increased pressures on recruitment. Fisheries and climate change, coupled with related local and global drivers such as pollution and sea ice change, have the potential to produce synergistic impacts that compound the risks to Antarctic fish and squid species. The uncertainty surrounding how different species will respond to these challenges, given their varying life histories, environmental dependencies, and resiliencies, necessitates regular assessment to inform conservation and management decisions. Urgent attention is needed to determine whether the current management strategies are suitably precautionary to achieve conservation objectives in light of the impending changes to the ecosystem.

MPAs in the Southern Ocean under CCAMLR

2021 ◽  
Vol 9 (1) ◽  
pp. 84-107
Author(s):  
Karen N. Scott
Keyword(s):  
Southern Ocean ◽  
Protected Area ◽  
Marine Protected Area ◽  
Ross Sea ◽  
Coastal Areas ◽  
Antarctic Marine ◽  
National Jurisdiction

Abstract In 2016, the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR) designated the largest marine protected area (MPA) in the Ross Sea. Hailed as both a precedent and a prototype for MPAs in both Antarctica and in areas beyond national jurisdiction more generally, it is nevertheless proving challenging to implement. Moreover, further MPAs have yet to be designated in the region although a number are under negotiation. This article will evaluate the contribution made by CCAMLR to the implementation of SDG 14.5 (the conservation of at least 20 per cent of marine and coastal areas by 2020), its relationship to area-based protection under the 1991 Environmental Protocol, and highlight the challenges of establishing MPAs beyond the jurisdiction of states.

scholarly journals Modeling the effect of Ross Ice Shelf melting on the Southern Ocean in quasi-equilibrium

2018 ◽  
Vol 12 (9) ◽  
pp. 3033-3044 ◽  
Author(s):  
Xiying Liu
Keyword(s):  
Southern Ocean ◽  
Sea Ice ◽  
Ross Sea ◽  
Global Ocean ◽  
Freshwater Flux ◽  
Quasi Equilibrium ◽  
Ice Shelf ◽  
Sea Ice Concentration ◽  
Ross Ice Shelf ◽  
Ice Concentration

Abstract. To study the influence of basal melting of the Ross Ice Shelf (BMRIS) on the Southern Ocean (ocean southward of 35∘ S) in quasi-equilibrium, numerical experiments with and without the BMRIS effect were performed using a global ocean–sea ice–ice shelf coupled model. In both experiments, the model started from a state of quasi-equilibrium ocean and was integrated for 500 years forced by CORE (Coordinated Ocean-ice Reference Experiment) normal-year atmospheric fields. The simulation results of the last 100 years were analyzed. The melt rate averaged over the entire Ross Ice Shelf is 0.25 m a−1, which is associated with a freshwater flux of 3.15 mSv (1 mSv = 103 m3 s−1). The extra freshwater flux decreases the salinity in the region from 1500 m depth to the sea floor in the southern Pacific and Indian oceans, with a maximum difference of nearly 0.005 PSU in the Pacific Ocean. Conversely, the effect of concurrent heat flux is mainly confined to the middle depth layer (approximately 1500 to 3000 m). The decreased density due to the BMRIS effect, together with the influence of ocean topography, creates local differences in circulation in the Ross Sea and nearby waters. Through advection by the Antarctic Circumpolar Current, the flux difference from BMRIS gives rise to an increase of sea ice thickness and sea ice concentration in the Ross Sea adjacent to the coast and ocean water to the east. Warm advection and accumulation of warm water associated with differences in local circulation decrease sea ice concentration on the margins of sea ice cover adjacent to open water in the Ross Sea in September. The decreased water density weakens the subpolar cell as well as the lower cell in the global residual meridional overturning circulation (MOC). Moreover, we observe accompanying reduced southward meridional heat transport at most latitudes of the Southern Ocean.

Holodentata gen. nov. (Isopoda: Asellota: Paramunnidae) with a description of two new species: H. caeca and H. triangulata from the Southern Ocean

Zootaxa ◽  
2009 ◽  
Vol 2096 (1) ◽  
pp. 395-412 ◽  
Author(s):  
BRENDA LÍA DOTI ◽  
MADHUMITA CHOUDHURY ◽  
ANGELIKA BRANDT
Keyword(s):  
New Species ◽  
Southern Ocean ◽  
Dorsal View ◽  
Type Species ◽  
New Genus ◽  
Ross Sea ◽  
Weddell Sea ◽  
Two New Species

A new genus of Paramunnidae, Holodentata (type species: Paramunna gaussi Vanhöffen, 1914) is erected. The new genus comprises two new species: H. caeca, from the deep Weddell Sea and H. triangulata, from the Ross Sea. The new genus is distinguished by the following characters: article 3 of the antenna short and with strong denticles, mandible palp absent, article 2 of maxilliped palp longest, coxal plates visible in dorsal view in all pereonites, pleotelson broad and laterally denticulated.

scholarly journals A First Genome Survey and Genomic SSR Marker Analysis of Trematomus loennbergii Regan, 1913

Animals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 3186
Author(s):  
Eunkyung Choi ◽  
Sun Hee Kim ◽  
Seung Jae Lee ◽  
Euna Jo ◽  
Jinmu Kim ◽  
...  
Keyword(s):  
Microsatellite Markers ◽  
Fish Species ◽  
Evolutionary Biology ◽  
Average Rate ◽  
Antarctic Fish ◽  
Error Rates ◽  
Repeat Motif ◽  
Sequencing Error ◽  
Genome Survey ◽  
Next Generation Sequencing Ngs

Trematomus loennbergii Regan, 1913, is an evolutionarily important marine fish species distributed in the Antarctic Ocean. However, its genome has not been studied to date. In the present study, whole genome sequencing was performed using next-generation sequencing (NGS) technology to characterize its genome and develop genomic microsatellite markers. The 25-mer frequency distribution was estimated to be the best, and the genome size was predicted to be 815,042,992 bp. The heterozygosity, average rate of read duplication, and sequencing error rates were 0.536%, 0.724%, and 0.292%, respectively. These data were used to analyze microsatellite markers, and a total of 2,264,647 repeat motifs were identified. The most frequent repeat motif was di-nucleotide with 87.00% frequency, followed by tri-nucleotide (10.45%), tetra-nucleotide (1.94%), penta-nucleotide (0.34%), and hexa-nucleotide (0.27%). The AC repeat motif was the most abundant motif among di-nucleotides and among all repeat motifs. Among microsatellite markers, 181 markers were selected and PCR technology was used to validate several markers. A total of 15 markers produced only one band. In summary, these results provide a good basis for further studies, including evolutionary biology studies and population genetics of Antarctic fish species.

scholarly journals Antarctic Fish as a Global Pollution Sensor: Metals Biomonitoring in a Twelve-Year Period

2021 ◽  
Vol 8 ◽  
Author(s):  
Alessandro Marrone ◽  
Daniele La Russa ◽  
Elvira Brunelli ◽  
Gianfranco Santovito ◽  
Mauro Francesco La Russa ◽  
...  
Keyword(s):  
Ross Sea ◽  
Antarctic Fish ◽  
Conservation Strategies ◽  
Early Step ◽  
Low Latitudes ◽  
Contamination Levels ◽  
Global Threat ◽  
Land Water ◽  
Natural Laboratory ◽  
Over Time

Antarctica represents a unique natural laboratory for ecotoxicological studies as it is characterized by low internal pollutants emissions but high external contamination levels. Indeed, warm temperatures promote pollutant evaporation (low latitudes), while cool temperatures (high latitudes) promote its deposition from the atmosphere on land/water. Metals are the most important pollutants in ecosystems and represent a serious and global threat to aquatic and terrestrial organisms. Since 2000, the risks posed by metals have led many States to ratify protocols aimed at reducing their emissions. Endemic Antarctic organisms represent excellent bioindicators in order to evaluate the efficacy of global measures adopted to mitigate pollutants release into the environment. In this study (supported by PNRA18-00133), we estimated the metals contamination levels and the metallothionein-1 expression in liver samples of two Antarctic fish species, the icefish Chionodraco hamatus and the red-blooded Trematomus bernacchii, collected in the same area during 2002 and 2014. The chosen area is located in the Ross Sea, a unique area as it is also isolated from the rest of the Southern Ocean. The analysis of contamination trends throughout this period showed, in both species, a significant increase over time of metals bioaccumulation and metallothionein-1 expression. In addition, our result clearly indicated that the detoxifying ability of the two organisms analyzed greatly differs, probably due to haemoglobin presence/absence. Our work represents an important early step to obtain valuable information in conservation strategies for both Antarctic and non-Antarctic ecosystems.

scholarly journals Carbonate saturation state of surface waters in the Ross Sea and Southern Ocean: controls and implications for the onset of aragonite undersaturation

2015 ◽  
Vol 12 (11) ◽  
pp. 8429-8465 ◽  
Author(s):  
H. B. DeJong ◽  
R. B. Dunbar ◽  
D. A. Mucciarone ◽  
D. A. Koweek
Keyword(s):  
Southern Ocean ◽  
Surface Waters ◽  
Ross Sea ◽  
Polar Front ◽  
Early Spring ◽  
Total Alkalinity ◽  
Saturation State ◽  
System Data ◽  
Algal Photosynthesis ◽  
Carbon System

Abstract. Predicting when surface waters of the Ross Sea and Southern Ocean will become undersaturated with respect to biogenic carbonate minerals is challenging in part due to the lack of baseline high resolution carbon system data. Here we present ~ 1700 surface total alkalinity measurements from the Ross Sea and along a transect between the Ross Sea and southern Chile from the austral autumn (February–March 2013). We calculate the saturation state of aragonite (ΩAr) and calcite (ΩCa) using measured total alkalinity and pCO2. In the Ross Sea and south of the Polar Front, variability in carbonate saturation state (Ω) is mainly driven by algal photosynthesis. Freshwater dilution and calcification have minimal influence on Ω variability. We estimate an early spring surface water ΩAr value of ~ 1.2 for the Ross Sea using a total alkalinity–salinity relationship and historical pCO2 measurements. Our results suggest that the Ross Sea is not likely to become undersaturated with respect to aragonite until the year 2070.

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