Mark S. Peterson, Ph.D.

Research Interests:
Fundulus jenkinsi Habitat and Reproduction

(with W.T. Slack, E.T. Lang, N. Brown-Peterson

Habitat characteristics and aspects of the reproductive life history of the saltmarsh topminnow, Fundulus jenkinsi, in Mississippi coastal watersheds, with the production of a comparative diagnostic key for young stages of select members of the genus Fundulus

Reproduction

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Plot of mean (± SEM) female and male gonadosomatic index (GSI) by month for Fundulus jenkinsi. In October, error bars were so small they were hidden by the data point symbol. Data points are significantly different (p ≤ 0.05) if letter labels are not the same, and not significantly different (p > 0.05) if the letter labels are the same. Plot of mean (± SEM) female and male gonadosomatic index (GSI) by month for Fundulus jenkinsi. In October, error bars were so small they were hidden by the data point symbol. Data points are significantly different (p ≤ 0.05) if letter labels are not the same, and not significantly different (p > 0.05) if the letter labels are the same.
Photographs illustrating spawning phases of female Fundulus jenkinsi: (A) Developing, (B) Spawning Capable, (C) Actively Spawning, and (D) Regressing. Oocyte stages are labeled as primary growth (PG), cortical alveoli (CA), early secondary growth (SGe), late secondary growth (SGl), full secondary growth (SGfg), Oocyte maturation (OM), postovulatory follicles (POF), and atresia. Photographs illustrating spawning phases of female Fundulus jenkinsi: (A) Developing, (B) Spawning Capable, (C) Actively Spawning, and (D) Regressing. Oocyte stages are labeled as primary growth (PG), cortical alveoli (CA), early secondary growth (SGe), late secondary growth (SGl), full secondary growth (SGfg), Oocyte maturation (OM), postovulatory follicles (POF), and atresia.
Plot of mean (± SEM) female Fundulus jenkinsi gonadosomatic index (GSI) between two spring tides with high tide (cm) by date. Data points are statistically different (p ≤ 0.05) if letter labels are not the same, and statistically similar (p > 0.05) if the letter labels are the same. Plot of mean (± SEM) female Fundulus jenkinsi gonadosomatic index (GSI) between two spring tides with high tide (cm) by date. Data points are statistically different (p ≤ 0.05) if letter labels are not the same, and statistically similar (p > 0.05) if the letter labels are the same.
Oocyte maturation and postovulatory follicles (POF) displayed with high tide (cm) by date. Oocyte maturation and postovulatory follicles (POF) displayed with high tide (cm) by date.
Image of a Fundulus jenkinsi (52.3 mm TL) ovarian  histological section showing various post ovulatory follicles (POF) along with  oocyte maturation (OM) stages. Image of a Fundulus jenkinsi (52.3 mm TL) ovarian histological section showing various post ovulatory follicles (POF) along with oocyte maturation (OM) stages.

 

Development

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Various stages (TL) of Adinia xenica development

Various stages (TL) of Adinia xenica development Arrows note mid-lateral pigment and largest size where internal pigment around spine is visible. Size class one (0-6.99 mm TL), size class two (7-9.99 mm), size class three (10-11.99 mm), and size class four (12-15 mm).

Various stages (TL) of Fundulus grandis development

Various stages (TL) of Fundulus grandis development Arrow indicates largest size where internal pigment around spine is visible. Size class one (0-6.99 mm TL), size class two (7-9.99 mm), size class three (10-11.99 mm), and size class four (12-15 mm).

Various stages (TL) of Fundulus jenkinsi development

Various stages (TL) of Fundulus jenkinsi development Arrows indicate concentration of pigment along dorsal midline extending from head to caudal peduncle; pigment forming sideways X or hourglass, and largest size where internal pigment around spine is visible. Size class one (0-6.99 mm TL), size class two (7-9.99 mm), size class three (10-11.99 mm), and size class four (12-15 mm).

Various stages (TL) of Fundulus pulvereus development

Various stages (TL) of Fundulus pulvereus development Arrows note interior hypaxial muscle pigment. Size class one (0-6.99 mm TL), size class two (7-9.99 mm), size class three (10-11.99 mm), and size class four (12-15 mm).

Various stages (TL) of Fundulus similis development

Various stages (TL) of Fundulus similis development Arrows indicate mid-lateral pigment, 3-5 rows of large large, stellate melanophores extending from head to dorsal fin origin; and largest size where internal pigment around spine is visible. Size class one (0 - 6.99 mm TL), size class two (7 - 9.99 mm), size class three (10 - 11.99 mm), and size class four (12 - 15 mm).