Spawning Periodicity and Reproductive Behavior of Fundulus heteroclitus in a New England Salt Marsh

The Mummichog, Fundulus heteroclitus, is a widely distributed fish that has been extensively researched in the southern portion of its range (south of Cape Cod, MA). During the summers of 2003 and 2004, we studied the reproductive ecology of F. heteroclitus in a northern population (Northeast Creek, Mount Desert Island, Maine). Our direct observations show that unlike more southern populations, northern F. heteroclitus spawns daily during its two-month spawning season, with no preference for spring tides over the entire season. However, within consecutive semidiurnal tides significantly more spawning was associated with the higher high tide. Spawning occurred on bare gravel and on mud associated with the grass Spartina patens. Spawning was highly promiscuous with males typically spawning in groups with females in very shallow water during receding tides. These temporal and spatial patterns of oviposition caused eggs to be deposited in a much broader range of habitats than in southern populations of this species. We present and evaluate critically several hypotheses that may explain the variation in spawning patterns observed in this species.

Fig. 1

Location of the study site. The study site is shown within the state of Maine, as well as its location on Mount Desert Island. The star represents the location of the study site on the inset of Northeast Creek.

Fig. 2

Temporal pattern of spawning for 2004 (see text for definition of Spawning index). Full and new moons are indicated by open and filled circles, respectively.

Fig. 3

Temporal patterns of female reproductive readiness for 2004 using either percentage of females collected that released ovulated eggs (black dots and line) or the average number of ovulated eggs per female (gray dots and line).

Fig. 4

Comparison of consecutive (within a 24-hour period) high tide observations for 2003 and 2004.

Fig. 5

Spawning intensity versus time relative to high tide. Data include all 2004 observations.

Contributor Notes

Associate Editor: E. Schultz.

¹ College of the Atlantic, Bar Harbor, Maine 04609, E-mail: chrisp@coa.edu. Send reprint requests to this address.

² College of the Atlantic, Bar Harbor, Maine 04609; Present address: School of Marine and Atmospheric Sciences, Stony Brook University, Stony Brook, New York 11794-5000, E-mail: Santiago.Salinas@stonybrook.edu.

³ Department of Biological Sciences, Illinois State University, Normal, Illinois 61790, E-mail: rlpresto@ilstu.edu.

⁴ Mount Desert Island Biological Laboratory, Salisbury Cove, Maine 04672, E-mail: gkidder@mdibl.org.

Received: 04 Dec 2008

Accepted: 18 Nov 2009