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Interview with Marine Mammal Researcher Dr. Ruth H. Carmichael on the Stranding of Dolphins, Manatees and Whales

Posted On April 15, 2014 by

This blog is part of a series of interviews with scientists who are championing marine research in the Gulf of Mexico.

We know there was a very significant increase in the number of marine mammal strandings observed following the BP Deepwater Horizon oil disaster. Dr. Ruth H. Carmichael talks to Ocean Conservancy about her work to respond to strandings when they occur, collect data to better understand these strandings and put together public outreach programs to prevent them in the future.

Dr. Ruth H. Carmichael is the senior marine scientist at the Dauphin Island Sea Lab and associate professor of marine sciences at the University of South Alabama. Her research seeks to better understand the biological and physiological responses of organisms to environmental change. She also studies how nutrient enrichment and pollution, coastal structures, climate change and harvest pressure affect coastal habitats and species. As the Alabama Marine Mammal Stranding Network coordinator, she serves as a first-responder for dolphins and other animals that get stranded on the Alabama coast.

Ocean Conservancy: Why do marine mammal strandings occur in the Gulf of Mexico?

Dr. Carmichael: Marine mammals strand for a variety of reasons, some natural and some influenced by people. Most often, in coastal Alabama, animals strand after death and the specific cause of death is unknown, but may be related to illness or disease, natural or man-made environmental stress, problems during calving, old age, or human interactions. NOAA’s National Marine Fisheries Service (NMFS) makes information on strandings available to the public.

OC: What exactly do marine scientists mean by the term “stranding,” and how historically extensive has this problem been in the Gulf?

Dr. C: Stranding refers to animals that wash ashore or are otherwise trapped or stuck in a location that is not normal or favorable for survival. This may occur when carcasses wash ashore after death or when animals are alive, such as dolphins ‘beaching’ or manatees orienting to a wastewater treatment plant outfall and failing to migrate when water temperatures turn cold.

OC: Can you talk specifically about dolphins and strandings, and what types of environmental conditions in the Gulf cause strandings?

Dr. C: In coastal Alabama the peak stranding period is usually in the spring, consistent with one of the two broad peaks in calving in our area. But strandings can and do occur year round. Since early 2010, the region has experienced an Unusual Mortality Event (UME), the cause of which has not been determined. Hence, relationships to overall conditions in the Gulf of Mexico ecosystem are hard to define. We know that timing and location of some strandings have been related to extreme cold events and an associated spring freshet in 2011. We also know from NOAA research that some animals have been in poorer body condition and experienced disease.

OC: As the Alabama Marine Mammal Stranding Network (ALMMSN) coordinator, you are the first call when someone reports a stranded animal. Tell us about your experience responding to those emergency calls.

Dr. C: Because the Alabama Marine Mammal Stranding network responds to all marine mammal strandings (cetaceans, such as dolphins and whales, as well as manatees), our response is divided based on federal oversight for these species.

I personally take all emergency calls for manatees in the states of Alabama and Mississippi that come into our 24-hour emergency hotline for strandings, sightings where the animal is still on site, and other issues of immediate concern. I then either respond directly, report the issue to enforcement if it involves harassment, or dispatch a team to respond depending on the nature of the call and the location of the event. In the case of manatee strandings, this usually means salvaging a carcass for necropsy the next day by a team of staff and volunteers. We have only had one known live manatee wash ashore in Alabama, and unfortunately that animal was in such poor condition that it could not survive transport. We do not hold or rehabilitate manatees.

For cetacean response, I have an excellent stranding coordinator, Noel Wingers, who takes all emergency calls for these species and makes decisions regarding direct response or dispatching a team, depending on the situation. In the case of cetaceans, which are under the northern Gulf of Mexico UME and managed a bit differently, response is also a bit different in terms of whether a carcass is salvaged or sampled and disposed of after necessary data are collected. For live cetacean strandings, in every case, we follow National Oceanic and Atmospheric Administration (NOAA) guidance regarding how animals are handled, transported and where they go for rehabilitation. The details are different for every case. We do not transport or rehabilitate cetaceans.

We also rely on assistance from municipal, county and state authorities to assist with moving and disposing carcasses in some cases, and we are very grateful for their support and cooperation.

OC: It has been four years since the BP Deepwater Horizon oil disaster began – what is the status of the ongoing research in your area of expertise? Are you as far along as you and your fellow researchers hoped to be by this point?

Dr. C: Since 2010, we have been unable to conduct any research on biological samples from stranded marine mammals. As the result of litigation over the UME, all samples taken from stranded marine mammals in the state of Alabama have been collected by NOAA. We don’t know when or if we will be able to retain samples or have previously collected samples returned to continue our regular program of diagnostic study.

OC: Is more work needed to establish clear baselines for healthy and sustainable populations of marine mammals in the Gulf? What still needs to be done? And how would you explain its significance to the public?

Dr. C: Yes, more data are needed to establish baselines. Very little research has been done on stranded marine mammals in the north central Gulf of Mexico, and Alabama in particular has been a ‘black hole’ for data. We have had inconsistent stranding response and data collection in the past. With the establishment of the ALMMSN at Dauphin Island Sea Lab we hope to provide continuous, consistent and scientifically rigorous data collection from stranded marine mammals to better and more rapidly define causes of death, define relationships between environmental variables and stranding patterns, and enhance survival of live stranded animals. A major need is funding to operate the ALMMSN and to train dedicated long-term personnel who will build capacity for future stranding response and research on marine mammals. The only way to ensure recovery and conservation of marine mammals throughout the region is to properly outfit and support operation of dedicated consistent stranding networks. We also require additional data on live animal populations in the region, including data on genetics, population structure, contaminant exposure, health and body condition, feeding dynamics, reproduction and interactions with other populations, among other basic ecological data that are not available for our area.

OC: There are many animals on the Gulf Coast that can get stranded in addition to dolphins, including whales, manatees, turtles and sea birds. Can you tell us more about the importance of these species and their role in the ecosystem?

Dr. C: Many of these species are threatened and endangered. All are part of our community heritage and the natural resources that make up a healthy Gulf of Mexico ecosystem. And many are sentinel or key species that reflect broader ecosystem health and function, with implications for commercial fisheries success and human health risks. They all also support local economies as part of a growing regional ecotourism industry.

OC: We know there was a very significant increase in the number of strandings observed following the BP Deepwater Horizon oil disaster. For example, 930 strandings were reported in the northern Gulf between February 2010 and April 2013. But these large numbers are just numbers to many people. Can you put these numbers in context? Has anything like this happened before?

Dr. C: Our stranding network is relatively new, but we can look at mean numbers of strandings reported historically in our area and make some comparisons. For example, in the past in Alabama (2007-2009) there were about a dozen strandings reported each year. During 2010-2013, numbers of strandings ranged from 25 to 60 animals each season. It is important to note that during historical periods, stranding response was sometimes inconsistent and we suspect strandings were under-reported, but this difference is still substantial, with at least two to five times more strandings after 2010.

OC: Given that strandings occurred before the BP oil disaster, are there patterns to the strandings that suggest causes other than exposure to oil? Your research with William M. Graham, Allen Aven, Graham Worthy and Stephen Howden suggests water temperature changes and unusual freshwater discharges may have played significant roles. The research also identified diet, nutrition and food web changes as likely contributing factors, correct?

Dr. C: Natural physical and chemical attributes of any system can affect when and where animals strand. These attributes interact with but do not preclude other factors that cause mortality. For example, a disease might result in mortality but the local water flow patterns may determine when and where the resulting carcasses wash ashore. Similarly, colder than usual temperature or exposure to oil related contaminants could affect the abundance, distribution and condition of prey species available as food for dolphins and other predators in affected areas. Altered food supply could, in turn, affect dolphin condition and susceptibility to disease or other stresses. Exposure to oil-derived substances could also directly affect the condition of animals in ways we don’t fully understand or have yet to discover. Hence, all of these factors can interact to directly, and indirectly, affect stranding dynamics.

OC: Lastly, why, after four years since the UME began, are the marine mammal stranding networks on the Gulf Coast still struggling to get the resources needed to carry out this important work?

Dr. C: I cannot answer for other networks, but in the case of the Alabama Marine Mammal Stranding Network at DISL, we are relatively new. It takes time to build a relationship with the public and with other stranding authorities, train personnel, and build infrastructure. We are very fortunate that we received support in our early months, during and just after the BP Deepwater Horizon oil disaster from NMFS and the National Fish & Wildlife Foundation for basic start-up equipment and response activities. We have excellent colleagues in the stranding network and the NMFS southeast region, who have helped train our personnel and answered many questions. The Alabama Department of Conservation and Natural Resources and the U.S. Fish & Wildlife Service have also been very supportive of our efforts.

It is also important to understand that all of the stranding networks in the Gulf of Mexico are over-extended in personnel time and other resources due to responding to the higher than usual number of strandings during the Gulf of Mexico UME. This has been the longest duration UME in Gulf history. As a result, most stranding networks remain in need of some additional support to maintain response quality and consistency. In Alabama, we have the added burden of beginning and institutionalizing a new program. This investment, however, is already paying off. Alabama now has a nearly four-year record of responding to 100 percent of marine mammal strandings reported in the state, providing mutual aid to neighboring networks, and performing full data collection, including biological sampling on 100 percent of the carcasses for which such data collection is appropriate. We are working hard to build stranding response capacity, to no longer be the ‘black hole’ for data in our region and to establish baselines needed to evaluate the BP Deepwater Horizon oil disaster, as well as prepare for, assess and respond to future catastrophic events.

OC: As an interesting side note, many folks in Alabama are probably familiar with the manatee license plates, stickers, and signs associated with the awareness program that you started in order to change people’s perception about Alabama’s resident manatees. Can you tell us about that outreach program, and what inspired you to start it?

Dr. C: We started our outreach campaign for manatee awareness in Alabama for two main reasons. First, we wanted to enlist the help of the public to learn more about when and where to find manatees in our area and to gather and analyze these publicly sourced data in a measurable way to support our subsequent research. Many Alabama and Mississippi residents are on the water regularly and have an opportunity to see these animals, but in the past, nobody was collecting and assimilating this information. We wanted to give the public a place to consistently report sightings in a specific way that would make them useful for us and other end users (including the public) to learn about manatee habits and habitat use. By reaching out to the public we could get them involved and functionally increase our knowledge about these animals and their movements in our area to support conservation.

Second, we wanted to use this program to share data back to the public and other authorities and let them know that manatees are here in local waters, and because of public participation in our research, we know more. We could then let local residents and policy makers know when and where to expect to find manatees in our area to guide boating practices, coastal project planning, habitat conservation and restoration activities. Our data combined with historical data we compiled allowed a change in classification of manatees from Accidental to Priority for conservation in our area now that we know these animals are regular at least seasonal visitors to our local northern Gulf of Mexico waters. Our data have also been useful to better understand home range of manatees throughout the Gulf of Mexico region between our local waters and Florida, which contributes to Gulf-wide resource conservation and management for this endangered species.

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