scholarly journals Peer Review #2 of "A possible new spawning area for Atlantic bluefin tuna (Thunnus thynnus): the first histologic evidence of reproductive activity in the southern Gulf of Mexico (v0.1)"

2019 ◽  
Keyword(s):  
Gulf Of Mexico ◽  
Peer Review ◽  
Bluefin Tuna ◽  
Reproductive Activity ◽  
Thunnus Thynnus ◽  
Atlantic Bluefin Tuna ◽  
Histologic Evidence ◽  
Spawning Area ◽  
Southern Gulf Of Mexico

scholarly journals A possible new spawning area for Atlantic bluefin tuna (Thunnus thynnus): the first histologic evidence of reproductive activity in the southern Gulf of Mexico

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e7187 ◽  
Author(s):  
Roberto Cruz-Castán ◽  
Sámar Saber ◽  
David Macías ◽  
María José Gómez Vives ◽  
Gabriela Galindo-Cortes ◽  
...  
Keyword(s):  
Gulf Of Mexico ◽  
Mediterranean Sea ◽  
Bluefin Tuna ◽  
Reproductive Activity ◽  
Western Atlantic ◽  
Atlantic Bluefin Tuna ◽  
Spawning Area ◽  
Spawning Areas ◽  
Southern Gulf Of Mexico ◽  
The Mediterranean

The number of studies of reproductive biology for Atlantic bluefin tuna carried out in the Gulf of Mexico is significantly lower than those undertaken in the Mediterranean Sea. Four spawning areas have been found for the eastern Atlantic bluefin tuna stock in the Mediterranean Sea, so it is not implausible that there is more than one spawning area in the Gulf of Mexico for the western Atlantic bluefin tuna stock. The individuals used in this study were caught as bycatch by the Mexican surface longline fleet between January and April 2015. A total of 63 individuals ranging between 192 and 293 cm LF (mean = 238 ± 22.52 cm) were measured. Gonads from 46 fish (31 females and 15 males) were collected for histological examination. All the individuals were classified as mature; 25 were reproductively active (in spawning capable and spawning stages). The histological analysis indicates spawning activity in Mexican waters (the southern Gulf of Mexico). Spawning occurred in March and April, when the sea surface temperature was 25.57 °C ± 0.69 in March and 27.03 °C ± 0.69 in April. Information on the location of the spawning areas is necessary for a correct management of species. The present study provides the first histological evidence of reproductive activity in Mexican waters, and indicates a wider spawning area, beyond just the northern zone, potentially encompassing the entire Gulf of Mexico.

Active prey selection in developing larvae of Atlantic bluefin tuna (Thunnus thynnus) in spawning grounds of the Gulf of Mexico

2021 ◽  
Author(s):  
Akihiro Shiroza ◽  
Estrella Malca ◽  
John T Lamkin ◽  
Trika Gerard ◽  
Michael R Landry ◽  
...  
Keyword(s):  
Gulf Of Mexico ◽  
Prey Selection ◽  
Bluefin Tuna ◽  
Gut Contents ◽  
Physical Factors ◽  
Larval Rearing ◽  
Thunnus Thynnus ◽  
Small Copepod ◽  
Atlantic Bluefin Tuna ◽  
Larval Stages

Abstract Bluefin tuna spawn in restricted areas of subtropical oligotrophic seas. Here, we investigate the zooplankton prey and feeding selectivity of early larval stages of Atlantic bluefin tuna (ABT, Thunnus thynnus) in larval rearing habitat of the Gulf of Mexico. Larvae and zooplankton were collected during two multi-day Lagrangian experiments during peak spawning in May 2017 and 2018. Larvae were categorized by flexion stage and standard length. We identified, enumerated and sized zooplankton from larval gut contents and in the ambient community. Ciliates were quantitatively important (up to 9%) in carbon-based diets of early larvae. As larvae grew, diet composition and prey selection shifted from small copepod nauplii and calanoid copepodites to larger podonid cladocerans, which accounted for up to 70% of ingested carbon. Even when cladoceran abundances were <0.2 m−3, they comprised 23% of postflexion stage diet. Feeding behaviors of larvae at different development stages were more specialized, and prey selection narrowed to appendicularians and primarily cladocerans when these taxa were more abundant. Our findings suggest that ABT larvae have the capacity to switch from passive selection, regulated by physical factors, to active selection of presumably energetically optimal prey.

Variability of preferred environmental conditions for Atlantic bluefin tuna (Thunnus thynnus) larvae in the Gulf of Mexico during 1993-2011

2016 ◽  
Vol 25 (3) ◽  
pp. 320-336 ◽  
Author(s):  
Ricardo Domingues ◽  
Gustavo Goni ◽  
Francis Bringas ◽  
Barbara Muhling ◽  
David Lindo-Atichati ◽  
...  
Keyword(s):  
Gulf Of Mexico ◽  
Environmental Conditions ◽  
Bluefin Tuna ◽  
Thunnus Thynnus ◽  
Atlantic Bluefin Tuna
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