After an analysis of archival museum specimens and recent collections, it is possible that Bermuda marine animal protection laws over the last three and a half decades may have lead to greatly reduced populations, or the total loss of several types of seaweed surrounding the islands.
The rocky intertidal in Bermuda today is a difficult habitat for the seasonal re-establishment of large seaweeds, a possible consequence of marine animal protections now in place. Protections were inaugurated in the 1970s to establish and maintain larger populations of charismatic fish, such as parrotfish as well as shellfish such as top shell snails.
These herbivores keep the coral reefs free of seaweed overgrowth in addition to bringing high economic value to the tourist-based island economy. The protections have succeeded, and herbivorous fish and snails have increased over the past three and a half decades.
Using thousands of archived specimens, Bermuda seaweeds from a century ago were compared with recent collections. Since the animal protection laws were put in place on the islands, intertidal and coastal populations of many types of seaweed have dramatically changed.
In their study published in Botanica Marina, researchers show that well-intended conservation laws usually do not always take into account all of the possible consequences of the intended protections. For example, their research illustrates how several large and abundant Bermuda seaweeds recorded in the early 20th century are no longer present or are only rarely collected today.
After the protection of marine herbivores, the potential losses in the seaweed community of the rocky-bottom ecosystem of Bermuda were likely not considered by legislators and environmental planners.
As such, archival specimens of seaweeds from one hundred years ago compared with extensive recent collections suggest a change in biodiversity for Bermuda that has occurred over the past century.
As the authors point out, conservation laws often do not consider all forms of native wildlife or the potential consequences these conservation measures could impact on other species.
All levels relating to food and nutrition of an environment need to be considered by environmental planners and managers when protecting specific populations of animals, as shown in this case when protecting tropical herbivorous fish and shellfish – the major consumers of seaweeds.