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Sexual maturity in western Atlantic bluefin tuna

View Article: PubMed Central - PubMed

ABSTRACT

We introduce a novel endocrine approach for assessing the unresolved matter of the timing of sexual maturation in western Atlantic bluefin tuna (ABFT), a highly migratory population whose status remains uncertain. Ratios of follicle stimulating hormone to luteinizing hormone, a sexual maturity indicator, in all ABFT ≥134 cm curved fork length (CFL) were <0.4, similar to Mediterranean spawners, indicating that western ABFT mature at considerably smaller sizes and at a much younger age than currently assumed (≥185 cm CFL).

No MeSH data available.


Related in: MedlinePlus

Gonad and fat body somatic indices.GSI and FSI presented as mean (±SDV). Males and females were grouped together. May fish were sampled in the Gulf of Mexico during spawning season. June–October fish were sampled on NW Atlantic foraging grounds: the Gulf of Maine, Nantucket Sound, Georges Bank and off Nova Scotia during foraging season. Normal distribution was achieved via arcsine transformation, and confirmed by Shapiro-Wilk W test. Lower case letters indicate significant difference between means (Tukey-Kramer, α = 0.05). Sample sizes are in parentheses (n).
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f1: Gonad and fat body somatic indices.GSI and FSI presented as mean (±SDV). Males and females were grouped together. May fish were sampled in the Gulf of Mexico during spawning season. June–October fish were sampled on NW Atlantic foraging grounds: the Gulf of Maine, Nantucket Sound, Georges Bank and off Nova Scotia during foraging season. Normal distribution was achieved via arcsine transformation, and confirmed by Shapiro-Wilk W test. Lower case letters indicate significant difference between means (Tukey-Kramer, α = 0.05). Sample sizes are in parentheses (n).

Mentions: ABFT gonad and perigonadal fat body indices (i.e. GSI and FSI) within each sampling region did not differ significantly between sexes or among sizes and were grouped together for statistical analyses. Mean GSI was significantly higher (p < 0.05) in fish sampled in the Gulf of Mexico (3.5 ± 1.26) than in fish sampled on foraging grounds (≤1.0) (Fig. 1). All gonads sampled in the NW Atlantic foraging grounds weighed 50–2100 g and were in a non-reproduction condition (as indicated by gonad weight and histology/oocyte morphology- e.g. lack of hydrated oocytes and post ovulatory follicles). Mean perigonadal fat body indices (FSI) were high in July (0.5 ± 0.23), decreased in August (0.2 ± 0.20), and then increased in October (0.6 ± 0.16). May fish (sampled in the Gulf of Mexico) had no perigonadal fat. In YOY the gonads were thin, almost unnoticeable, and with no detectable perigonadal fat.


Sexual maturity in western Atlantic bluefin tuna
Gonad and fat body somatic indices.GSI and FSI presented as mean (±SDV). Males and females were grouped together. May fish were sampled in the Gulf of Mexico during spawning season. June–October fish were sampled on NW Atlantic foraging grounds: the Gulf of Maine, Nantucket Sound, Georges Bank and off Nova Scotia during foraging season. Normal distribution was achieved via arcsine transformation, and confirmed by Shapiro-Wilk W test. Lower case letters indicate significant difference between means (Tukey-Kramer, α = 0.05). Sample sizes are in parentheses (n).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5384251&req=5

f1: Gonad and fat body somatic indices.GSI and FSI presented as mean (±SDV). Males and females were grouped together. May fish were sampled in the Gulf of Mexico during spawning season. June–October fish were sampled on NW Atlantic foraging grounds: the Gulf of Maine, Nantucket Sound, Georges Bank and off Nova Scotia during foraging season. Normal distribution was achieved via arcsine transformation, and confirmed by Shapiro-Wilk W test. Lower case letters indicate significant difference between means (Tukey-Kramer, α = 0.05). Sample sizes are in parentheses (n).
Mentions: ABFT gonad and perigonadal fat body indices (i.e. GSI and FSI) within each sampling region did not differ significantly between sexes or among sizes and were grouped together for statistical analyses. Mean GSI was significantly higher (p < 0.05) in fish sampled in the Gulf of Mexico (3.5 ± 1.26) than in fish sampled on foraging grounds (≤1.0) (Fig. 1). All gonads sampled in the NW Atlantic foraging grounds weighed 50–2100 g and were in a non-reproduction condition (as indicated by gonad weight and histology/oocyte morphology- e.g. lack of hydrated oocytes and post ovulatory follicles). Mean perigonadal fat body indices (FSI) were high in July (0.5 ± 0.23), decreased in August (0.2 ± 0.20), and then increased in October (0.6 ± 0.16). May fish (sampled in the Gulf of Mexico) had no perigonadal fat. In YOY the gonads were thin, almost unnoticeable, and with no detectable perigonadal fat.

View Article: PubMed Central - PubMed

ABSTRACT

We introduce a novel endocrine approach for assessing the unresolved matter of the timing of sexual maturation in western Atlantic bluefin tuna (ABFT), a highly migratory population whose status remains uncertain. Ratios of follicle stimulating hormone to luteinizing hormone, a sexual maturity indicator, in all ABFT &ge;134&#8197;cm curved fork length (CFL) were &lt;0.4, similar to Mediterranean spawners, indicating that western ABFT mature at considerably smaller sizes and at a much younger age than currently assumed (&ge;185&#8197;cm CFL).

No MeSH data available.


Related in: MedlinePlus