A recent study conducted by University of Maine researchers has revealed significant changes in the habitat preferences and population dynamics of American lobsters along Maine’s coast. Over the past few decades, there has been a notable shift in the distribution of adult lobsters, with a decline in boulder shelter habitats and an increase in sediment and featureless ledge habitats. This change in habitat use has implications for the overall health of the lobster population, as well as for conservation efforts and fisheries management practices.
One of the key findings of the study is the decline in lobster population density across all types of habitats, indicating a decrease in the overall number of lobsters in these areas. This decline in population density has coincided with an increase in water temperatures, which have risen nearly 3 degrees Celsius over the past few decades. The researchers also noted changes in the abundance of kelp and algal turfs within lobster habitats, further highlighting the impact of environmental factors on lobster populations and their habitats.
The study also found that while the overall population density of lobsters has decreased, the mean size of adult lobsters has increased over the years. This increase in mean size is attributed to fewer juvenile lobsters residing in these habitats, suggesting potential shifts in the demographics of the lobster population. Despite the increase in size, the majority of lobsters observed were still smaller than the minimum legal size for harvesting, which is a positive indicator for the fishery.
Another interesting finding of the study is the changing behavior of lobsters in choosing habitats. Lobsters are now favoring open spaces within their habitats over rocky shelters, with a decrease in the percentage of lobsters living under rocky shelters and an increase in those using no shelter at all or underneath beds of algae. These shifts in habitat preference may be influenced by factors such as competition between individual lobsters, availability of food sources, and the presence of predators in the area.
The researchers also highlighted the importance of understanding how lobsters use different types of habitats in assessing the health of the overall lobster population. By filling in information gaps about habitat preferences and changes over time, the study provides valuable insights for lobster stock assessments and fisheries management practices. The findings of the study were published in the journal Marine Ecology Progress Series and involved a thorough investigation of 20 sites along Maine’s coast, from York to Jonesport, including data collection on lobster populations, habitat types, and water temperatures.
Overall, the study sheds light on the complex interactions between American lobsters and their habitats, showing how environmental changes and shifts in habitat preferences can impact the population dynamics and size distribution of lobsters. These findings have important implications for conservation efforts, fisheries management practices, and our understanding of how marine species adapt to changing environmental conditions. The researchers emphasize the importance of continued monitoring and research to better understand and protect this iconic and commercially important marine species.
