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The reproductive ecology of the Antarctic bivalve Aequiyoldia eightsii (Protobranchia: Sareptidae) follows neither Antarctic nor taxonomic patterns

The reproductive ecology of the Antarctic bivalve Aequiyoldia eightsii (Protobranchia: Sareptidae) follows neither Antarctic nor taxonomic patterns
The reproductive ecology of the Antarctic bivalve Aequiyoldia eightsii (Protobranchia: Sareptidae) follows neither Antarctic nor taxonomic patterns
The accepted paradigm for reproduction in Antarctic marine species is one where oogenesis takes 18 months to 2 years, and a bimodal egg-size distribution where two cohorts of eggs are present in female gonads throughout the year. These slow gametogenic traits are driven by low temperature and/or the restriction of resource availability because of extreme seasonality in the marine environment. Here we present data on the reproductive ecology of the common Antarctic bivalve Aequiyoldia eightsii (Jay, 1839) (Protobranchia: Sarepidae) from monthly samples collected between January 2013 and May 2014 at Hangar Cove, Rothera Point on the West Antarctic Peninsula. These data show that A. eightsii is unusual because it does not follow the typical pattern expected for reproduction in Antarctic marine invertebrates, and differs also from closely related nuculanid protobranch bivalves with respect to gametogenic duration and reproductive periodicity. Continuous oogenesis, evidenced by the year-round occurrence of previtellogenic, vitellogenic, and ripe oocytes in female gonads, is supplemented by a seasonal increase in reproductive intensity and spawning in Austral winter (April–May), evidenced by the loss of mature
spermatozoa and ripe oocytes from males and females, respectively. The simultaneous occurrence of these contrasting traits in individuals is attributed to a flexible feeding strategy (suspension and deposit feeding) in response to seasonal changes in food supply characteristic of the Antarctic marine environment. Asynchrony between individual females is also notable. We
hypothesise that the variability may represent a trade-off between somatic and reproductive growth, and previously reported internal interannual cycles in shell growth.
0722-4060
1-14
Lau, Sally C.Y.
d5573018-a7fd-4c53-bcb4-cdcb71b1f817
Grange, Laura J.
8de65684-8e14-4cc2-89d1-ca20322714e4
Peck, Lloyd S.
097d27ed-4644-4bc1-a855-045029ace2df
Reed, Adam J.
ec734ee2-469c-4259-91d6-4abcfbe65e3b
Lau, Sally C.Y.
d5573018-a7fd-4c53-bcb4-cdcb71b1f817
Grange, Laura J.
8de65684-8e14-4cc2-89d1-ca20322714e4
Peck, Lloyd S.
097d27ed-4644-4bc1-a855-045029ace2df
Reed, Adam J.
ec734ee2-469c-4259-91d6-4abcfbe65e3b

Lau, Sally C.Y., Grange, Laura J., Peck, Lloyd S. and Reed, Adam J. (2018) The reproductive ecology of the Antarctic bivalve Aequiyoldia eightsii (Protobranchia: Sareptidae) follows neither Antarctic nor taxonomic patterns. Polar Biology, 1-14. (doi:10.1007/s00300-018-2309-2).

Record type: Article

Abstract

The accepted paradigm for reproduction in Antarctic marine species is one where oogenesis takes 18 months to 2 years, and a bimodal egg-size distribution where two cohorts of eggs are present in female gonads throughout the year. These slow gametogenic traits are driven by low temperature and/or the restriction of resource availability because of extreme seasonality in the marine environment. Here we present data on the reproductive ecology of the common Antarctic bivalve Aequiyoldia eightsii (Jay, 1839) (Protobranchia: Sarepidae) from monthly samples collected between January 2013 and May 2014 at Hangar Cove, Rothera Point on the West Antarctic Peninsula. These data show that A. eightsii is unusual because it does not follow the typical pattern expected for reproduction in Antarctic marine invertebrates, and differs also from closely related nuculanid protobranch bivalves with respect to gametogenic duration and reproductive periodicity. Continuous oogenesis, evidenced by the year-round occurrence of previtellogenic, vitellogenic, and ripe oocytes in female gonads, is supplemented by a seasonal increase in reproductive intensity and spawning in Austral winter (April–May), evidenced by the loss of mature
spermatozoa and ripe oocytes from males and females, respectively. The simultaneous occurrence of these contrasting traits in individuals is attributed to a flexible feeding strategy (suspension and deposit feeding) in response to seasonal changes in food supply characteristic of the Antarctic marine environment. Asynchrony between individual females is also notable. We
hypothesise that the variability may represent a trade-off between somatic and reproductive growth, and previously reported internal interannual cycles in shell growth.

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Accepted/In Press date: 13 March 2018
e-pub ahead of print date: 27 March 2018

Identifiers

Local EPrints ID: 419203
URI: https://eprints.soton.ac.uk/id/eprint/419203
ISSN: 0722-4060
PURE UUID: 955f3289-ab9b-45bf-bc8e-5df0946fd4ab
ORCID for Laura J. Grange: ORCID iD orcid.org/0000-0001-9222-6848

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Date deposited: 09 Apr 2018 16:30
Last modified: 14 Mar 2019 01:34

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