scholarly journals A first assessment of atresia in the Chilean jack mackerel Trachurus murphyi (Teleostei, Carangidae) from the South-eastern Pacific Ocean

2020 ◽  
Vol 55 (2) ◽  
pp. 100
Author(s):  
Paola González-Kother ◽  
M. Teresa González ◽  
Marcelo E. Oliva
Keyword(s):  
Pacific Ocean ◽  
Condition Factor ◽  
Gonadosomatic Index ◽  
Eastern Pacific ◽  
Batch Fecundity ◽  
Eastern Pacific Ocean ◽  
Jack Mackerel ◽  
South Eastern ◽  
Relative Fecundity ◽  
Trachurus Murphyi

The Chilean jack mackerel Trachurus murphyi support an important fishery in the South-eastern Pacific Ocean and has declined considerably over time. T. murphyi have asynchronous ovarian development with an oceanic spawning (September to January). Despite the economic importance of this resource critical issue such as characteristics and dynamics of atresia, which affect the reproductive output, are unknown. Females of T. murphyi caught in different spawning seasons were analysed to describe patterns of prevalence and intensity of atresia. General linear models (GLM) were performed by using prevalence and intensity atresia as response variables and gonadosomatic index, condition factor, sea surface temperature, postovulatory follicles and month/year as explanatory variables. The batch fecundity and relative fecundity were compared between females showing atresia, postovulatory follicles and non-atretic females. The stages of atresia identified were alpha, beta and gamma. The GLM showed that variations in the prevalence and intensity of atresia were explained for all variables, except condition factor for prevalence, and gonadosomatic index for intensity of atresia. According to our results, the dynamic of alpha and beta atresia could be considered a potential proxy for any disruption of spawning season. The batch fecundity and relative fecundity were lowest compared with other Trachurus spp. This is the first assessment comparing fecundity between atretic and not atretic females for this species.

Genetic population structure in the Chilean jack mackerel, Trachurus murphyi (Nichols) across the South-eastern Pacific Ocean

2009 ◽  
Vol 100 (2) ◽  
pp. 109-115 ◽  
Author(s):  
Leyla Cárdenas ◽  
Andrea X. Silva ◽  
Antonios Magoulas ◽  
Josefina Cabezas ◽  
Elie Poulin ◽  
...  
Keyword(s):  
Population Structure ◽  
Pacific Ocean ◽  
Eastern Pacific ◽  
Genetic Population Structure ◽  
Eastern Pacific Ocean ◽  
Jack Mackerel ◽  
The South ◽  
Genetic Population ◽  
South Eastern ◽  
Trachurus Murphyi

scholarly journals Discovering sounds in Patagonia, characterizing sei whale (<i>Balaenoptera borealis</i>) downsweeps in the south-eastern Pacific Ocean

2018 ◽  
Author(s):  
Sonia Español-Jiménez ◽  
Paulina A. Bahamonde ◽  
Gustavo Chiang ◽  
Verena Häussermann
Keyword(s):  
Pacific Ocean ◽  
Peak Frequency ◽  
Eastern Pacific ◽  
Absolute Maximum ◽  
Maximum Frequency ◽  
Eastern Pacific Ocean ◽  
The South ◽  
South Eastern ◽  
Average Maximum ◽  
The Absolute

Abstract. Sei whales (Balaenoptera borealis) is the least known whale species. Information on sei whale´s vocalizations in the south-eastern Pacific Ocean and its regional variability are even more scarce than that from other ocean areas. This research presents the first characterization of sei whale sounds recorded in Chile during austral autumn of 2016 and 2017. A total of 41 calls have been attributed to sei whale’s downsweeps. In 2016, calls ranged from an average maximum frequency of 105.3 Hz down to an average minimum 35.6 Hz over 1.6 s with a peak frequency of 65.4 Hz. During 2017, calls ranged from an average maximum frequency of 93.3 Hz down to 42.2 Hz (over 1.6 s) with a peak frequency of 68.3 Hz. The absolute minimum frequency recorded was 30 Hz and the absolute maximum frequency was 129.4 Hz. Calls generally occurred in pairs, but triplets or singles were also registered. These low frequency sounds share characteristics with recordings of sei whales near the Hawaii Islands, but with differences in the maximum frequencies and duration. These calls distinctly differ from sounds previously described for sei whales in the Southern Ocean and are the first documented sei whale calls in the South-eastern Pacific.

scholarly journals Pelagic longline fishery for albacore tuna (Thunnus alalunga) yellowfin tuna (Thunnus albacares) and bigeye tuna (Thunnus obesus) in the high seas of eastern Pacific ocean.

2018 ◽  
Author(s):  
Bruno Thierry Nyatchouba Nsangue ◽  
Zhou Cheng ◽  
Liuxiong Xu ◽  
Richard Kindong
Keyword(s):  
Pacific Ocean ◽  
Condition Factor ◽  
Yellowfin Tuna ◽  
Eastern Pacific ◽  
Bigeye Tuna ◽  
Eastern Pacific Ocean ◽  
Albacore Tuna ◽  
Thunnus Obesus ◽  
Hook Depth ◽  
High Seas

This study highlighted the occurrence of a pelagic long line fishery targeting albacore tuna, yellowfin tuna and bigeye tuna in the high seas of eastern Pacific Ocean. Species selectivity of the fishing method was assessed. Hook depth, statistics of at-vessel survival rate grouped by hooks number, length frequency, weight frequency, length weight relationship, relative condition factor and Fulton’s condition factor were estimated for the target species. This fishing method proved highly selective for albacore tuna, where catches accounted for about 85% of catches, while other resources such as yellowfin tuna amounted to 4.8% and big eye tuna accounted for 9.70%. The results showed that, fish size increased with deeper depths. Hook No. 8 located at a critical depth indicated that fork lengths of tuna registered above this depth were significantly smaller than that those captured below it. Logistic regression model suggested a significant effect of hook depth on the catch efficiency. The highest density of catch efficiency was located at the depth of 167.57 m. An alternative strategy showed that hooks deployed at the depths ranging from 124 to 211 m will result in a more considerable fishing efficiency. The analyses also showed that the relative condition factors (Krel) of the three fish species were greater than (1) implying that they were in good physiological condition at the time of capture.

New digeneans (Opecoelidae) from hydrothermal vent fishes in the south eastern Pacific Ocean, including one new genus and five new species

Zootaxa ◽  
2014 ◽  
Vol 3768 (1) ◽  
pp. 73 ◽  
Author(s):  
R. A. BRAY ◽  
A. WAESCHENBACH ◽  
P. DYAL ◽  
D. T.J. LITTLEWOOD ◽  
S. MORAND
Keyword(s):  
New Species ◽  
Pacific Ocean ◽  
Hydrothermal Vent ◽  
New Genus ◽  
Eastern Pacific ◽  
Eastern Pacific Ocean ◽  
The South ◽  
South Eastern

scholarly journals Pelagic longline fishery for albacore tuna (Thunnus alalunga) yellowfin tuna (Thunnus albacares) and bigeye tuna (Thunnus obesus) in the high seas of eastern Pacific ocean.

2018 ◽  
Author(s):  
Bruno Thierry Nyatchouba Nsangue ◽  
Zhou Cheng ◽  
Liuxiong Xu ◽  
Richard Kindong
Keyword(s):  
Pacific Ocean ◽  
Condition Factor ◽  
Yellowfin Tuna ◽  
Eastern Pacific ◽  
Bigeye Tuna ◽  
Eastern Pacific Ocean ◽  
Albacore Tuna ◽  
Thunnus Obesus ◽  
Hook Depth ◽  
High Seas

This study highlighted the occurrence of a pelagic long line fishery targeting albacore tuna, yellowfin tuna and bigeye tuna in the high seas of eastern Pacific Ocean. Species selectivity of the fishing method was assessed. Hook depth, statistics of at-vessel survival rate grouped by hooks number, length frequency, weight frequency, length weight relationship, relative condition factor and Fulton’s condition factor were estimated for the target species. This fishing method proved highly selective for albacore tuna, where catches accounted for about 85% of catches, while other resources such as yellowfin tuna amounted to 4.8% and big eye tuna accounted for 9.70%. The results showed that, fish size increased with deeper depths. Hook No. 8 located at a critical depth indicated that fork lengths of tuna registered above this depth were significantly smaller than that those captured below it. Logistic regression model suggested a significant effect of hook depth on the catch efficiency. The highest density of catch efficiency was located at the depth of 167.57 m. An alternative strategy showed that hooks deployed at the depths ranging from 124 to 211 m will result in a more considerable fishing efficiency. The analyses also showed that the relative condition factors (Krel) of the three fish species were greater than (1) implying that they were in good physiological condition at the time of capture.

Sign in / Sign up

Export Citation Format

Share Document