Use of local ecological knowledge to investigate endangered baleen whale recovery in the Falkland Islands

By SRC intern, Molly Rickles

In this study, Frans and Auge looked at baleen whale population in the Falkland Islands in the post-whaling era. Due to whaling in the early 1900s, whale populations here have decreased dramatically, but recent observations suggest that their numbers are currently increasing. However, there is a lack of population data, making this study critical.

Methods

The main goal of the research was to understand how well the baleen whale population is doing post-whaling in the Falkland Islands. To do this, the scientists used LEK, or local ecological knowledge. In this method, interviews were conducted with local Falkland residents to determine how often whales are sighted off the coast. The residents were asked to draw pictures on a map of where they saw the whales. Each interview was given a reliability rating based on how confident and detailed the account was. This data was used to supplement the existing International Whaling Committee data from the whaling era. With the combined data, the researchers aimed to look at when the whale sightings were most common and to determine the most common places where the whales were seen.

SRC pic 1

Results

Over the course of the study, 3,842 whale sightings were recorded and Falkland residents recorded 631 of those observations. Since LEK is not always a reliable method, it was determined that about 70% of the observations recorded using LEK were reliable, and could be used in the study. It was found that in the 1970’s, no whale sightings were recorded because it was right after the whaling era. By the early 2000’s, the number of whale sightings increased 11-fold, showing a population recovery. Out of all of the baleen whale species, sei whales (Balaenoptera borealis) showed the largest increase since the whaling era, and are currently the most abundant whale species in the Falkland Islands. It was also determined that baleen whales are most common during the summer and fall months, based on recorded sightings.

Outcomes

This study was an important step in understanding baleen whale populations and how they have recovered since the whaling era. Using LEK allowed the scientists to get population data even when there was a lack of empirical data, which is a new technique that hasn’t been used regularly in other studies. This new technique allowed the researchers to determine baleen whale populations in the Falkland Islands, which can be used as a reference for the future of whale conservation. This is especially critical now because of the increasing threats to whales, such as increasing economic development in the Falkland Islands. Since the whales have recovered from the whaling era, it is now important to keep the population healthy, and this study provides an important monitoring tool for future conservation efforts.

SRC pic 2

References

Frans, V.F., & Auge, A. A. (2016). Use of local ecological knowledge to investigate endangered baleen whale recovery in the Falkland Islands. Biological Conservation, 202, 127-137. dio: 10.1016/j.biocon.2016.08.017

Baleen whales host a unique gut microbiome with similarities to both carnivores and herbivores

By Julia Whidden, RJD Graduate Student

“Microbiome” is the term used to describe the communities of microorganisms that live inside a host, and includes microorganisms that are beneficial, detrimental, and neutral to host health. Some of these microorganisms are vital to digestion, but the diversity, composition, function, and source of an animal’s microbiome is still largely understood. For example, the microbiome of the herbivorous panda bear was expected to host communities similar to other herbivores with the same diet, while in actuality its communities were discovered to be more similar to other closely related yet omnivorous pandas. Cetaceans, or dolphins and whales, evolved from artiodactyls, which were terrestrial animals that fed on plants. Other modern-day animals evolved from artiodactyls include cows and hippopotamuses, or ruminants, and are similar to this ancestor in their herbivorous diet. The main polysaccharide, or large carbohydrate that herbivores acquire from their diet is cellulose. Whales, however, are carnivorous. Even baleen whales that are filter feeders consume small fish and crustaceans, digesting another large carbohydrate, chitin, from the ‘shells’ of their prey. Despite vastly different diets, ruminants and whales share a multichambered foregut, which is used in these animals to help digest the tough structure of the large polysaccharides they consume. This study investigated the microbiome of baleen whales to determine whether their community composition was more similar to their ancestor and distant relatives, the herbivores, or to their carnivorous diet.

Whale baleen

Fecal samples were collected from wild baleen whales in the Bay of Fundy, Canada, in August 2011, and were complemented by samples of captive cetaceans and wild terrestrial animals. The wild fecal samples were obtained by first locating and identifying the whales, and then samples were scooped from the water immediately following defecation. Captive cetacean and wild terrestrial animal samples included Pacific Humpback whales, Atlantic white-sided dolphins, bottlenose dolphins, Beluga whales, hippopotamus, and other unnamed wild terrestrial carnivores and herbivores. DNA extraction from the fecal samples isolated 16S ribosomal RNA (rRNA), which is involved in protein synthesis in ribosomes. An analysis of 16S community sequence was performed, which indicates the diversity in a microbiome by identifying the number of gene variants present, assuming each microorganism has a different variant of the gene. The microbiome diversity within each group of animals – including the baleen whales, toothed whales, terrestrial herbivores, and terrestrial carnivores to name a few – was then compared (see Figure 1 below).

Screen Shot 2015-10-17 at 10.26.23 PM

Results indicated that the microorganisms of the baleen whale’s microbiome involved in the digestion of polysaccharides were similar to those of terrestrial herbivores. This is intuitive, as the chitin that the baleen whales consume is similar in structure and function to the cellulose that herbivores consume. Further, the baleen whale microorganisms responsible for breaking down proteins and building amino acids – which make up proteins – were more similar to the microbiome of the terrestrial carnivores analyzed. This study concluded that microbiome composition is determined by a mix of the host’s past and present, incorporating microorganisms associated with their ancestor’s diet, as well as their modern diet.