Telling males and females apart should be easy, but with many animal species, it is not so obvious. Unless sexual dimorphism (obvious gender differences in body characteristics and coloration patterns), deciding who is a male or a female can be tricky. n bottlenose dolphins, body shape, size and colorations are basically identical for males and females and there are no major external features that allow for sex differentiation. So we have to rely on other clues.
Dolphin Saddle was first seen in Monterey Bay in October 1990. It has a very distinctive dorsal fin. Saddle is a “putative male”. This means that we are relatively certain he is a male because we have photographed “him” over a five-year period consecutively and we never saw him accompanied by a calf. Given that a female reproductive interval (the time between calves) is 4-5 years, and given that Saddle is at least 33 years old (he was identified in Santa Barbara as an adult in 1987), we would expect to have seen a calf with him if he was a female during these five years….and infact Saddle has never been seen with a calf in any of the study areas where it has been sighted: Santa Barbara, San Diego and Santa Monica Bay.
But we are not 100% sure our assumptions are accurate yet and we are looking closely at all of our known females to determine the average interval between calves. The more females with calves we are able to follow, the better we are going to be at predicting the sex of an unknown animal.
Of course there are other methods as well do determine the sex of a dolphin. The best would be to be able to collect a piece of skin from the animal and then do a genetic test in the lab to determine whether the animal has two X (female) or an X and a Y chromosome (male).
But collecting a piece of skin from a wild ranging animal that is free to come and go as it pleases and that does not have to cooperate with science if it does not want to, is not as easy as it seems. The most common method among scientists is to use a cross-bow (Medieval-style) armed with specially designed arrows that have a collecting cup at the tip instead of an arrow-point. The cup is made of stainless steel and it is designed to penetrate the animal’s blubber layer to extract a small plug the size of a pencil eraser. The shot actually results in a fast prick, much like an injection, and has been quite successful on a variety of dolphin and whale species worldwide.
People often cringe at the thought of seeing animals being harassed this way, and most scientists admit that they would prefer other methods, if there were easily available ones. But most other methods involve capturing the animal which is stressful, dangerous, and often not feasible in the wild (except for certain special areas where the water is calm and shallow). A capture is also extremely costly and risky. Many studies have been done on the reaction of the animal to the extraction of a small piece of skin and blubber using biopsies and it has been shown, thanks to multiple videos and careful monitoring of post-biopsy behavior, that the animals seem to react more strongly to a missed shot (such as the arrow hitting the water next to them), because of the noise it makes, rather than to a hit. Many animals return to bow-ride or to approach the boat right after the biopsy has been taken. Others are a bit more shy….but the shyness is temporary. In very rare cases, the animals are more cautious of the boat that approached them during biopsy sampling.
In the case of Saddle we have not been able to obtain a biopsy. Another way of determining sex is to take a lucky photo of the genital area of the dolphin's underside. This is not easy to do in murky water and unfortunately, California water is not so clear most of the time.
So we are left with the inference made from his sighting history since 1987, the photos we have, and the associations with other animals. Who is to say that in the near future we will have new information about this animal and either be proven right or wrong….For now, we are making an educated guess.
The analytical work associated with the project is proceeding slow but steady. At the moment we forged a collaboration with scientists located in San Diego to compare notes and get a full history of all the dolphins we photographed between 1990 and 2011 in Monterey Bay to match them to catalogs for Ensenada, Mexico, San Diego, Orange County, Los Angeles, Santa Barbara and San Francisco. Soon we will have a full picture of the dolphins history for the entire coastline over the last 30 years!!!
I hope you are enjoying the monthly updates we are providing. Each dolphin is unique and it is in the individuality of each animal that rests the key to understanding how they are surviving along the California coastline. Stay tuned for next month’s report and please keep supporting us if you can, your help is more critical than ever as the analysis of the data is a costly and time consuming process and it is the coronation of all the years spent in the field collecting the information.
At about 37 years of age, Miss is still the center of male attention. She moved to Monterey Bay from the Southern California Bight (where she was probably born) in 1990 and used the bay’s waters consistently up to today. From our research, we know that these dolphins can make forays into other areas of the coastline at any time, so Miss does travel back and forth from southern to central California and back, but Monterey Bay seems to have become a core area for her. Our colleagues in San Francisco have also seen her in San Francisco Bay, which is the northernmost limit of these dolphins range as far as we know. This is interesting in itself as these dolphins did not use to frequent central California waters at all in historical times, and they seem to have moved north past Point Conception (considered the oceanographic boundary between Central and Southern California), during the very strong El Nino Southern Oscillation event of 1982-83, when water temperatures increased along the California coast and warmer water species moved north following this anomalous “warm water” conditions.
But the dolphins did not move back permanently to the south after normal conditions returned. They adopted Monterey Bay as a preferred area and are found there year-round and now are moving farther and farther north. Their habitual use of San Francisco Bay only started in 2010 and every year there seem to be more dolphins regularly using the northern boundary. This is potentially a climate change effect as colder waters are becoming warmer worldwide and the dolphins may prove to be, once again, the ambassadors of our changing world.
Over the years, Miss has raised several calves, in fact, she is the female that we have most regularly seen with a newborn every 4-5 years. The first calf we followed has become an independent adult named Bullett and we are currently trying to follow, through our photographs over the years, the other calves she had to see if we can determine who they are as an adult (it is a long and tedious process which involves going through hundreds of photographs in a meticulous way and this is what I spend most of my nights doing at the moment).
The name Miss originally came from the fact that she is missing a big chunk of her dorsal fin along the “trailing edge” (back portion), but the “center-stage” behavior of this accomplished female always struck me as regal and the name came to have a double-meaning.
As an accomplished mother, Miss is always in the middle of a mother-calf group. These groups generally consist of several females with similar-age calves and females affiliated with these groups swim close together for several years until the calf they are raising becomes independent. Other studies in different parts of the world have shown that females join these groups to share “baby-sitting” duties with other mothers, to help one another with protecting calves from potential predators (sharks) and male dolphins, and to give one another some breathing space to forage without having to look after a lively and clumsy calf. Inexperienced mothers benefit from watching and perhaps imitating accomplished mothers while rearing their first calf and this may help in ensuring the calf’s survival during the 4-5 years it remains with its mother.
These groups are also a fantastic opportunity for the young ones to find paly mates and to forge bonds that will last in their adult age as they get to know and recognize one another and perhaps establish a sort of hierarchy as well.
In Monterey Bay, mother-calf groups are seen swimming either in the front or at the back of a larger school of dolphins, and are often the ones that travel in very shallow waters, almost touching their bellies to the sand. They are also more wary of our research boat and we are very conscious of their need to keep the young ones away from potential dangers, as the calves are curious and playful and readily approach and investigate new things. Mothers often, “recall” a naughty calf by slapping their tail repeatedly on the water to get their attention and sometime use this behavior as a warning to us or other dolphins if we accidentally wonder to close to their baby.
Miss’s first calf, Bullett had a unique dorsal fin. No major notches but a thick appearance and a rounded top which made the fin easily recognizable over time. Bullett was born in 1990 and started becoming independent n 1995, still around its mother but starting to associate with other adults as well. Unfortunately, without getting a glimpse of Bullett’s genital area (which is hard to do in Monterey Bay because the water is hardly ever clear enough), or without being able to collect a small piece of skin using biopsy sampling, we are not able to tell the sex of this animal. Maybe one day Bullett will have a calf and then we will know it is a she. Or maybe we will be able to capture a photo of Bulett leaping out of the water showing its belly, or better yet, we will be able to collect a small sample of its skin and genetically determine its sex.
Miss is an interesting dolphin for many reasons. She is the first dolphin in Monterey Bay that gave me an insight into how prolific dolphins could really be, as she was still weaning Bullett when she gave birth to another calf after barely 5 years from Bullett’s birth. This finding challenges the idea that females accompanied by their calves are reproductively unavailable to males (i.e., they do not go into estrus while mothering). Maybe they are not for some time after the calf is born but they are ready to reproduce once the calf is older and becoming more independent. Looking at Miss’ reproductive history and following her calves is giving us insights on female reproductive rates, calving success and mother/calf bonds.
As I mentioned in last month’s report, our study is now at a stage where data are being analyzed and readied for scientific publication and public consumption, but it took 25 years to get to this point as the process of following an animal that lives as long as the researcher is no small feat.
So far, the donations from Global Giving from the day we became a featured project have amounted to $9612 from 136 wonderful individuals who believed in us and have been the lifeline of this project. The majority of these funds is being held in our project account until we will have enough funds to be able to operate. We were able to use some of the money to analyze two samples for contaminants and 12 samples for mercury (which I will report on in one of my next monthly chats) and to conduct a few boat surveys. However, we are not able to operate to full capacity until our goal is reached. Without your support this project would have ceased to exist. At this time, we do not have any other source of funding (despite trying very hard to get support from agencies and private foundations) and in order to be able to deliver the goals of this project we need an additional $79,638.
In order to put our boat in the water we need to be able to maintain it to safety standards, insure it, support the staff that is engaged in the work and support the time it takes to produce reports, analyze data and liaise with the public through lectures and on-the-ground work. In addition, samples need to be sent to the lab for analysis and one sample could cost up to 1500$ to analyze. I am sharing this information with you so that you know why and how much we need your help to continue to do this work which is a full-time endeavor for myself and three others, the bulk of our small non-profit.
I sincerely hope you are enjoying this new format of communication and that you value our work. This is part of my life’s work and it is a privilege to share with you what I am finding as I analyze this considerable dataset.
One Dolphin per Month for One Year, this is a new program I am starting to tell you about our project.....because I think the best way to tell you about it is to let the dolphins speak.......
Trino is a key dolphin to my story because she was the first one identified in my study. She was first seen on October 9, 1990 by my friend Tom Norris who is really the one person who got me involved in studying them. I only first saw her with my own eyes in August 1991, when I started going out to sea on my own. I named her Trino because of her three evenly spaced notches on her dorsal fin. It became clear that Trino was a female because she was consistently accompanied by her calf Newbie at that time. Newbie was already a few months old when we first saw Trino. We could tell from its size and the size of its dorsal fin compared to its mother’s. As a good calf should do, Newbie was always swimming close to Trino, almost touching her body. The mother-calf bond is one of the strongest bonds in bottlenose dolphin societies and lasts between four and six years. During this time the calf learns the basic skills necessary for survival as well as the identity and character of its mother’s preferred associates. It also gets to become acquainted with calves of similar age which will likely become later associates in life. Over time, calves swim progressively farther and farther from their mother either in the company of other calves or temporarily associating with other adult dolphins (especially other females). This is when it gets pretty confusing for us researchers to tell who the mother of a particular calf is. In the case of Trino and Newbie, their relationship was pretty clear and we continued to see them together for at least five years.
Trino has moved on to have more calves, but Newbie will always be special in my mind because it was the first one I got to know and observe. One surprising thing we learned about Trino is that she is at least 32 years old as of 2015. How do we know how old Trino is?
Well, we asked around….We collaborate with researchers along the California coast and each research group collects photographs of the same dolphins in different areas of the California coastline, San Diego, Orange County, Santa Monica Bay, Santa Barbara, Monterey Bay (us) and San Francisco Bay. In1988, Dr. RH Defran, now Professor Emeritus at San Diego State University, and his students photographed Trino in San Diego, as an adult. She looked exactly as she does now, with her slight but defined evenly spaced notches on the dorsal…. So we calculated her age based on what we know (2015-1988=27 years as an adult plus at least 5 years as a calf). I am 51 so these dolphins have been around at least since I was in high school!!! I matched Trino’s dorsal fin to the San Diego catalog as a Master student, as this was part of my thesis work. A lot has happened since then, but Trino has been in my life ever since.
Walvis Bay, Namibia
I am reflecting upon the past 20 years as I look out over the Atlantic ocean and see the desert sand blowing from the dunes into the water. The place I am in now is actually very similar to my beloved California coast. If I close my eyes I can see it. Yet I am so far away. I am working on a poulation of bottlenose dolphins that lives along the coastline here in Namibia and in a manner very similar to the California dolphins that my project of 20 years has been studying. Except that these dolphins live in a much less congested and overcrowded coastline. However, development is arriving here as well and the dolphins are going to be facing the same threats and the same challenges the California coastal dolphins have already faced, and are facing every day: pollution from noise and chemicals, encroaching of their habitat by fishing gear, ship traffic, pleasure crafts and mining andindustrial operations. Humanity loves to repeat itself over and over....
In the past year I have been working non-stop to try to collate the data that Okeanis has been collecting over the years since its inception, and all the information that came before Okeanis was even founded. I guess I have been around longer than the organization itself, and my intention has always been to tell the story of the California dolphins. I never realized when I started that this would be a lifetime endeavour. These dolphins have accompanied me through life like a family, and have seen my development as a scientist and as a person. They survived with me heartbreaks and divorce, relocations and unemployment and all of life's little joys and sorrows. And after 20 years, we are still working together the dolphins and I, to try to understand each other, and to patch together a story of their life along the California coast.
Althoug we cannot exactly talk o each other in words the dolphins are nonetheless telling me their story through the photographs I have collected. Each photograph of a dolphin's dorsal fin is a map. It tells you the identity of the dolphin by looking at the nicks and notches found along the trainling edge (the back) of the dorsal. It tells you about the scars on the dolphin body. Sometime their shape and position reveals the story about the interactions a dolphin had, a wound from a shark bite, a collision with a sharp object, an altercation with another dolphin. Even the number of rakemarks from other dolphins' teeth can sometime tell me about the status of the animal in a hyerarchy. If a wound is fresh I can tell this from the photo as well, and I can look at sequences of photos of the same animal over the years to find out how long it takes for scars to heal.
California dolphins are affected by a variety of skin conditions which show as coloration patterns (often fungal in nature) or scabs and pustules on the body or round marks that become red and infected. California dolphins seem to suffer from a herpes-like condition, a form of pox-virus, which shows up on their body as round marks with either dark or light edges. What we are finding by looking at sequences of photos of the same individual over the years is that this condition seems to be latent in the animal, just like herpes is in people. Remember those stressful times at the office that caused that painful sore to come out on your mouth? Well, this seems to be the same thing that happens to the dolphins. One year their skin appears fine and the next year they are affected by a severe skin condition.
Our data indicates that there are periods of time when more dolphins appear to show this condition. Could it be stress? We are investigating this more closely because we do not know yet the exact relationship between the condition and the status of an animal. We do know that water temperature changes can cause stress, so as an animal moves from warmer to colder waters like these dolphins do (moving from San Diego to San Francisco on a regular basis now), the skin can undergo chemical changes that may cause stress. But there are other possible stressors, such as the contaminants that these animals are exposed to.
We have collected 46 skin and blubber samples for these animals to analyze them for contamination. Each sample is very expensive to analyze (over 1000$) and in order to be able to compare samples we need to run them all at the same time, with the same metrics, at the same lab. We have been unable to do this because we have not been able to raise enough money to send all the samples to the lab. So we are waiting for our finances to pan out. In the meantime we continue to work with the data we have.
Last year we took a bit of a pause from major field work....we need to get the data in order to be able to publish our results. I think it is difficult to convery how long and laborious the process of analyzing each photo we took over a 12 year period is. We have over 10,000 photographic records and each photo is entered into a database, graded for quality, compared to a catalog to identify the individual and then looked at for information about that individual.
Our catalog contains about 350 dolphins. Some of these animals are over 50 years old and have been roaming the waters between San Diego and San Francisco for as long as I have been alive. We are starting to understand their group composition and their movement patterns.
Dolphins started moving north from their habitual feeding ground in San Diego and the Southern California Bight in the 1980s after a major El Nino event warmed the waters north of Point Conception and pushed the dolphins north looking for new feeding grounds. Ever since some animals have made a new life in more northerly latitudes and as a few years ago these dolphins have started entering San Francisco Bay, an historical event.
Climate change is pushing these animals farther and farther north. We are finding that the first animals to move were the same females that dared moving to Monterey Bay and Central California in the 80s....These few individuals are the "rule breakers" and the pioneers in this population.
These are some of the tidbits from the project for this reporting period. Do not forget to visit our website (address below) to look at the catalog and to read a bit more from our publications.
Thank you for continuing to support us. Being such as samll organization with only a few individuals doing all of the work, we have very limited time and resources to get to do it all. So your help and the contributions that Global Giving makes to our project are truly a gift to us.
September to November is the best time to be in the water in Monterey Bay. The climate is milder this time of year and the waters are calmer. Our staff has been travelling the world in the meantime working on dolphins in similar environments to acquirecomparative data. Daniela Maldini, the Chief Scientist is currently in Namibia working on a similar population of bottlenose dolphins to understand whether skin lesions here are similar or different in nature from the skin lesions we are seeing in our animals in California. Understanding similarities and differences is just another way of checking weather contamination or different environmental conditions contribute to the health issues seen in the dolphins.
FIeld Director Mark Cotter is in California as we speak preparing the boat for another field season. In order to be able to get back in the water we need to check the motor, the hu and the trailer for wear and tear, damage and weak spots. Our boat is old and proper maintenance is key to having an operational and safe vessel in the cold water conditions of Monterey Bay.
We will have fresh news for you as the field season progresses.
Your support has been the only way we have been able to make it so far. Please continue to help us any way you can.
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