Program summary 

Conservation impact 

If long-term conservation programs are to be effective, it's critical to understand animal populations and their habitats. Research projects at HSWRI examine a number of physical and biological factors that influence the health of marine animal populations. Marine mammal strandings, as distressing as they are to witness, provide researchers with a unique point of contact with creatures whose behavior and movements are usually a mystery. Understanding the role that diseases play in regulating population abundance, or the role that environmental changes play in marine animal distribution provides resource managers with the information they need to manage species and their habitats. It also provides them with the ability to predict, and therefore perhaps prevent, catastrophic events that could threaten biodiversity and vitality of ocean ecosystems. 

In recent months, marine mammals and pelicans residing in the Indian River Lagoon (IRL) have been experiencing a significant increase in mortality.  Since July 2012, over 100 manatees have died in the lagoon in Brevard County alone.  In February 2013, an increase in pelican mortality was also documented.  In fact since February nearly 300 deceased pelicans have been recovered in the estuary.  The high mortality numbers of these two species has led to the declaration by the federal government of an Unusual Mortality Event (UME).  While the cause of the ongoing mortality remains unknown, there does not appear to be a direct link between the two species, with manatees suffering from acute mortality and pelican mortality resulting from chronic issues which are grossly reflected as emaciation.  While not currently considered part of the UME, bottlenose dolphins residing in the IRL have also been experiencing an increase in mortality since Dec. 2012.  A total of 38 dolphins have been recovered dead within the lagoon since Dec. 2012, a number more than twice that of the historical mean. Grossly dolphin mortality appears more similar to pelicans which are being recovered in an emaciated state, however future investigation is needed to determine if any of these mortalities are linked or the result of a cascade of events resulting from the catastrophic seagrass loss. 

Dolphins residing in the Indian River Lagoon estuary have been the focus of many HSWRI ecological and health related studies. The IRL dolphin population has recently been designated as a separate bottlenose dolphin stock and is considered a strategic stock since the number of human induced injuries and mortalities likely exceeds the potential biological removal.  Furthermore, IRL dolphins have been subjected to two Unusual Mortalities Events (2001, 2008) of unknown origin, and have been described an immune compromised population.

The IRL is North America’s most diverse estuary and over 4,000 plant and animal species inhabit the lagoon.  The estuary represents a threatened ecosystem and dolphins, as apex predator, can serve as an indicator species for studying the ecological impacts facing the IRL.  The investigations underway by HSWRI are essential for the development of effective management and conservation solutions to address this crisis.