Future Projects

Sea Star Hybridization in the Gulf of Maine

There is significant hybridization between Asterias forbesi (Forbes' sea star) and Asterias rubens (Common starfish) sea stars in the Gulf of Maine, likely due to climate change. Rapid warming has made the two species’ habitats, which are ordinarily separated based on different preferred temperature ranges, less stratified (pers. Comm. Dr. Kenneth Sebens, University of Washington). I would like to conduct an independent research project on the extent of hybridization between Asterias forbesi and Asterias rubens sea stars in the Gulf of Maine and examine how their habitat distribution has changed.

Both Asterias species are keystone species and occupy important, though different niches (Giakoumis et al 2023). The two species differ in their temperature tolerance, with A. rubens preferring cooler waters than A. forbesi (GIakoumis et al, 2023). The trophic implications of this transition are unknown, but A. rubens occupies a larger niche than A. forbesi (Giakoumis et al. 2023). If A. rubens is being outcompeted and bred out by hybrid stars, elements of its ecosystem role may be left unfulfilled. I would like to look at long-term data to determine how the distribution of the two species of stars has changed in the past 30 years.

Dr. Ken Sebens’ Lab in the University of Washington’s Biology Department has long-term benthic monitoring photographs from the Gulf of Maine dating back to at least 1990 and a dataset for mobile species (including Asterias spp.) in the photographs. I have annotated many of these photographs and translated them into the mobile species dataset myself and it would be the first source I would use to assess the hybrid presence in the Gulf of Maine across time. Ganzell and Steinwachs (2025) proved that it is possible to differentiate the hybrids morphologically, making the photographic evidence usable. If there are enough viable photographs, it may only take a couple of months to sort the photographs and gather the necessary data.

Below is an example figure displaying an expected outcome of sea star demographic change as the Gulf warms.

Project Proposal: Blue Crab Interactions with Invasive Crab Species in American Northeast.

Invasive Japanese shore crabs (Hemigrapsus sanguineus) and European green crab (Carcinus maenas) have been present along the Northeast coast of the US for decades, with interactions between C. maenas and blue crabs (Callinectes sapidus) being well documented (Smith et al. 2025). Rising ocean temperatures have allowed blue crabs to expand further North and remain for longer periods of time. This expansion has led to more interaction between C. sapidus and H. sanguineus as of recent. Blue crabs prey on other crab species, including C. maenas, and have served as effective population control where their ranges overlap (deRivera et al. 2005). Long-term expansion of C. sapidus has major implications for coastal ecosystems. It is possible that blue crabs could serve as population control for invasive crab species, or they could add increased pressure on an already struggling region.

Given how blue crabs have historically struggled to survive the colder Northeastern waters, it must also be discussed whether their establishment in this ecosystem would be an invasion not unlike that of C. maenas and H. sanguineus. The effects of blue crab invasion have been observed in the Mediterranean Sea, so it may serve as an important case study to understand how introduction of C. sapidus changes an ecosystem. The Mediterranean is much warmer than the waters of the Northeastern United States, but both regions are warming at a rate far greater than average (pers. comm. Dr. Kenneth Sebens, University of Washington).

Below is an example figure outlining what agonistic interaction success/"win" percentage may look like between crab species at different sizes/life stages.

Blue crabs in a lab in Chioggia, Italy

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