Dataset Information

Ampelisca eschrichtii Kroyer, 1842 (Ampeliscidae) of the Sakhalin Shelf in the Okhotsk Sea starve in summer and feast in winter.

ABSTRACT: Background:Ampelisca eschrichtii Krøyer, 1842 of the Sakhalin Shelf of the Okhotsk Sea, Far Eastern Russia, comprise the highest known biomass concentration of any amphipod population in the world and are a critically important prey source for western gray whales. Growth and reproduction in this population has not been apparent in summer. However, they are not accessible for sampling in winter to test a previous default conclusion that they grow and reproduce in winter. Methods:We tested the default winter growth and reproduction hypothesis by detailed comparisons of the brood and gonad development among 40 females and 14 males and brood sizes among females observed since 2002. Our test included six predictions of reproductive synchrony that would be apparent from gonad and brood morphology if active reproduction occurs in summer. Results:We found high prevalences of undersized and damaged oocytes, undersized broods, a lack of females brooding fully formed juveniles, atrophied ovaries, and males with mature sperm but lacking fully developed secondary sex morphologies required for pelagic mating. All of these conditions are consistent with trophic stress and starvation. Discussion:These A. eschrichtii populations therefore appear to starve in summer and to grow and reproduce in winter. The Offshore A. eschrichtii populations occur in summer below water strata bearing high phytoplankton biomasses. These populations are more likely to feed successfully in winter when storms mix phytoplankton to their depths.

SUBMITTER: Durkina VB

PROVIDER: S-EPMC6016533 | biostudies-literature | 2018

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

<i>Ampelisca eschrichtii</i> Krøyer, 1842 (<i>Ampeliscidae</i>) of the Sakhalin Shelf in the Okhotsk Sea starve in summer and feast in winter.

Durkina Valentina B VB Chapman John W JW Demchenko Natalia L NL

PeerJ 20180622

<h4>Background</h4><i>Ampelisca eschrichtii</i> Krøyer, 1842 of the Sakhalin Shelf of the Okhotsk Sea, Far Eastern Russia, comprise the highest known biomass concentration of any amphipod population in the world and are a critically important prey source for western gray whales. Growth and reproduction in this population has not been apparent in summer. However, they are not accessible for sampling in winter to test a previous default conclusion that they grow and reproduce in winter.<h4>Methods ...[more]

PMID: 29942674

Similar Datasets

Project description:BackgroundFemales of the gammaridean amphipod Ampelisca eschrichtii with signs of regenerating, previously atrophied ovaries were recovered from the northeastern shelf of Sakhalin Island (Okhotsk Sea, Russia). Ovarian regeneration was previously unknown for any amphipod species. A. eschrichtii have a predominantly 2-year life cycle (from embryo to adult death) and reproduce once between late winter or early spring at the age of 2 years. Occasionally, females survive to a third year. An adaptive value of extended survival among these females is likely to require that they are also reproductive.MethodsHistological sections from a second-year female with ovarian atrophy, a female with normal ovaries, a third-year female with ovarian regeneration, as well as testes of an immature and a sexually mature male were compared to determine the sources of cells of the germinal and somatic lines necessary for ovarian regeneration.ResultsOvarian regeneration in the third-year female began with the formation of a new germinal zone from germ cells preserved in the atrophied ovaries and eosinophilic cells of the previously starving second-year female. Eosinophilic cells form the mesodermal component of the germinal zone. A mass of these cells appeared in the second-year female that had atrophied ovaries and in large numbers on the intestine wall of the third-year female with regenerating ovaries. These eosinophilic cells appear to migrate into the regenerating ovaries.ConclusionsAll germ cells of the second-year female are not lost during ovarian atrophy and can be involved in subsequent ovarian regeneration. Eosinophilic cells involved in ovarian regeneration are of mesodermal origin. The eosinophilic cell morphologies are similar to those of quiescence cells (cells in a reversible state that do not divide but retain the ability to re-enter cell division and participate in regeneration). These histological data thus indicate that eosinophilic and germ cells of third-year females can participate in the regeneration of the ovaries to reproduce a second brood. The precursors of these third-year females (a small number the second-year females with an asynchronous [summer] breeding period and ovaries that have atrophied due to seasonal starvation) appear to possess sources of somatic and germ cells that are sufficient for ovarian regeneration and that may be adaptations to starvation stress.

Dataset Information

Ampelisca eschrichtii Kroyer, 1842 (Ampeliscidae) of the Sakhalin Shelf in the Okhotsk Sea starve in summer and feast in winter.

Publications

<i>Ampelisca eschrichtii</i> Krøyer, 1842 (<i>Ampeliscidae</i>) of the Sakhalin Shelf in the Okhotsk Sea starve in summer and feast in winter.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets