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Distribution, population biology, and trophic ecology of the deepwater demersal fish Halosauropsis macrochir (Pisces: Halosauridae) on the mid-Atlantic Ridge.

Bergstad OA, Clark L, Hansen HØ, Cousins N - PLoS ONE (2012)

Bottom Line: The majority of samples had a surplus of males.Diet analysis showed that H. macrochir feeds on Crustacea, Teleostei, Polychaeta, and Cephalopoda, but few prey could be identified to lower taxonomical levels.The mid-Atlantic Ridge constitutes a major portion of the North Atlantic living space of the abyssal halosaur where it completes its full life cycle, primarily as an actively foraging euryophagous micronekton/epibenthos and infauna feeder, becoming a partial piscivore with increasing size.

View Article: PubMed Central - PubMed

Affiliation: Institute of Marine Research, Flødevigen, His, Norway. oddaksel@imr.no

ABSTRACT
Halosauropsis macrochir ranked amongst the most abundant and widespread demersal fishes on the mid-Atlantic Ridge of the North Atlantic (Iceland-Azores) with greatest abundance at 1700-3500 m. All sizes, ranging from 10-76 cm total length, occurred in the area without any apparent spatial pattern or depth trend. Using otolith sections displaying growth increments assumed to represent annuli, the age range recorded was 2-36 years, but most individuals were <20 years. Length and weight at age data were used to fit growth models. No differences between sexes in length and weight at age were observed. The majority of samples had a surplus of males. Diet analysis showed that H. macrochir feeds on Crustacea, Teleostei, Polychaeta, and Cephalopoda, but few prey could be identified to lower taxonomical levels. The mid-Atlantic Ridge constitutes a major portion of the North Atlantic living space of the abyssal halosaur where it completes its full life cycle, primarily as an actively foraging euryophagous micronekton/epibenthos and infauna feeder, becoming a partial piscivore with increasing size.

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Transverse section of otoliths (sagittae) of Halosauropsis macrochir, displaying growth zones assumed to be annuli.Photo: Lise Heggbakken, Institute of Marine Research, Norway.
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pone-0031493-g006: Transverse section of otoliths (sagittae) of Halosauropsis macrochir, displaying growth zones assumed to be annuli.Photo: Lise Heggbakken, Institute of Marine Research, Norway.

Mentions: There was a linear relationship between otolith size (maximum antero-posterior distance) and total body length. Figure 6 shows examples of otolith sections and growth zones regarded as annuli. Age frequency distributions for both males and females were unimodal and skewed towards rather high ages (Fig. 7). The overall age range was 2–36 years, but only very few fish were older than 20 years.


Distribution, population biology, and trophic ecology of the deepwater demersal fish Halosauropsis macrochir (Pisces: Halosauridae) on the mid-Atlantic Ridge.

Bergstad OA, Clark L, Hansen HØ, Cousins N - PLoS ONE (2012)

Transverse section of otoliths (sagittae) of Halosauropsis macrochir, displaying growth zones assumed to be annuli.Photo: Lise Heggbakken, Institute of Marine Research, Norway.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3285165&req=5

pone-0031493-g006: Transverse section of otoliths (sagittae) of Halosauropsis macrochir, displaying growth zones assumed to be annuli.Photo: Lise Heggbakken, Institute of Marine Research, Norway.
Mentions: There was a linear relationship between otolith size (maximum antero-posterior distance) and total body length. Figure 6 shows examples of otolith sections and growth zones regarded as annuli. Age frequency distributions for both males and females were unimodal and skewed towards rather high ages (Fig. 7). The overall age range was 2–36 years, but only very few fish were older than 20 years.

Bottom Line: The majority of samples had a surplus of males.Diet analysis showed that H. macrochir feeds on Crustacea, Teleostei, Polychaeta, and Cephalopoda, but few prey could be identified to lower taxonomical levels.The mid-Atlantic Ridge constitutes a major portion of the North Atlantic living space of the abyssal halosaur where it completes its full life cycle, primarily as an actively foraging euryophagous micronekton/epibenthos and infauna feeder, becoming a partial piscivore with increasing size.

View Article: PubMed Central - PubMed

Affiliation: Institute of Marine Research, Flødevigen, His, Norway. oddaksel@imr.no

ABSTRACT
Halosauropsis macrochir ranked amongst the most abundant and widespread demersal fishes on the mid-Atlantic Ridge of the North Atlantic (Iceland-Azores) with greatest abundance at 1700-3500 m. All sizes, ranging from 10-76 cm total length, occurred in the area without any apparent spatial pattern or depth trend. Using otolith sections displaying growth increments assumed to represent annuli, the age range recorded was 2-36 years, but most individuals were <20 years. Length and weight at age data were used to fit growth models. No differences between sexes in length and weight at age were observed. The majority of samples had a surplus of males. Diet analysis showed that H. macrochir feeds on Crustacea, Teleostei, Polychaeta, and Cephalopoda, but few prey could be identified to lower taxonomical levels. The mid-Atlantic Ridge constitutes a major portion of the North Atlantic living space of the abyssal halosaur where it completes its full life cycle, primarily as an actively foraging euryophagous micronekton/epibenthos and infauna feeder, becoming a partial piscivore with increasing size.

Show MeSH