Dolphin Explorer Chronicles

Very Cold Water Temperature Today

The surface water temperature was 54 degrees on our 1:00pm trip today. Very cold! But the dolphins appear to be uneffected. Our sightings suggest that the dolphins are in larger groups in colder water...and very active and social. This cold water is slowing down the fish making feeding easier for the dolphins.  

The Dolphins - From our Catalogue to Their Community

Kent Morse

10,000 Island Dolphin Project

 

The 240 dolphins in this database are organized both alphabetically, according to the names we have given to them and numerically, based on where the most distinguishing feature appears on their dorsal fin.  This approach is helpful to us as we try to keep them separate in our minds, but that is about the limit of its usefulness.  And in fact this system obscures a much richer reality.  It is that richer, more nuanced reality - the way these dolphins organize themselves through patterns of association, kinship and overlapping home ranges - that I will endeavor to restore in the following three introductory essays. 

As you explore the database, using tools like the queries and Google Earth will help you take the individuals out of the arbitrary lists that serve our needs and return them to a much more interesting organizational system – that of their own societies.  The Google Earth application on this website, in which each recorded sighting is presented in a visual form, will give you a good feel for the home range of a particular dolphin.  The association pattern query in which you discover who a particular dolphin’s closest associates are will begin to reveal the social structure of the community.

We have collected enough data that a tantalizingly clear picture of the dolphin population around Naples, Marco Island and the northernmost portion of the 10,000 Islands is starting to emerge.  The fun thing is that this is an incomplete picture and that new information is coming in each day.  This website is an invitation to join with us in making sense of this new information and filling out the contours of the emerging picture.  Keep in mind that survey work is ongoing and the job of analyzing photos and entering the data from the previous five years is still a work in progress.

In our endeavor to document the dolphin population in our area, we have adapted an approach developed by scientists of the Sarasota Dolphin Research Program (SDRP) in the 1970’s.  Much of what we know about bottlenose dolphins comes from the over forty years of research they have done on the population of dolphins in and about Sarasota Bay. 

In trying to understand what we see during our surveys or the patterns that emerge from our data, we again turn to their pioneering work.  To give just one example, after a few hundred surveys of an area one starts to notice that while the social arrangement of the local dolphins is quite fluid, a few very consistent associations appear.  Mothers and their calves form an obvious bond that a casual observer would easily recognize.  But what is one to make of the repeated sighting of two large dolphins, roughly equal in size, that whomever else they happen to be with, are always with each other?  In this case it is extremely helpful that Randall Wells and his associates at the SDRP long ago documented the tendency of male bottlenose dolphins to form enduring bonds as they reach maturity.  Recognizing these ‘male pair bonds’ or ‘alliances’ allows one to identify many of the adult males in the community and that is no small thing.

In most cases we are assuming that we can apply insights gained from the study of dolphins in Sarasota Bay to the population of dolphins that live in our survey area.  So far that appears to be a safe assumption though there are some differences: most of the calves in Sarasota bay are born in the spring and summer; in our area most calves are born in the fall and early winter.

The three following entries are a first attempt at describing the population numbers and social make-up of the dolphins in our area of Southwest Florida.  Each focuses on one or two of the areas in which we have conducted surveys.  This is a work in progress and two things will help us refine our understanding of these dolphins.  The first is additional information generated by our continuing survey work; the second is your questions and insights as you explore the database – so, get to work.

The Dolphins of Area One

Kent Morse,

10,000 Island Dolphin Project

 

Randall Wells, program director for the Sarasota Dolphin Research Program, has described the distribution of bottlenose dolphins along the gulf coast of Florida as “a mosaic of slightly overlapping home ranges of different dolphin communities.”  Let’s see how this model applies to the dolphins in our study area.

 

Each bottlenose dolphin whose dorsal fin appears in this database is a member of one or another of these overlapping communities of resident dolphins. This essay will focus on the community of dolphins whose range falls within Area One  (yellow on the chart to the right).  We have done relatively few surveys in areas Two (white), Three (red) and Four (black), but Area One has been traversed over a thousand times, with surveys occurring during every month of the past five years, a period in which over 3000 dolphin sightings have been recorded. This has been sufficient to give us a clear idea of the make-up of this community.

 

Any time you draw an arbitrary line as we have done in designating the route we take to conduct Area One surveys, you are likely to find yourself in the heart of one dolphin’s home range, at one extreme of another’s, and just outside that of a third. This will be reflected in the frequency with which you encounter any given dolphin while conducting surveys along that arbitrary line.

So, for example, should you query the database, limiting the scope of your inquiry to area 1 surveys, you will find that Halfway, an adult female, has been encountered 274 times while, in the same time period, two other females KayCee and Crusty were encountered 20 times and 17 time respectively.  Disastre, likely an adult male, was encountered only three times in the five years under consideration here.

 We are clearly in the heart of Halfway’s range.  A smattering of sightings appear near the northern and southern extreme of the area 1 transect, but the vast majority – 216 – occur between marker 5 at the beginning of the intercoastal waterway around the Isles of Capri sea wall and into the Marco River.

              

              

           Halfway with her third and most recent calf, Kaya

 

Kaycee’s sighting history suggests a different story.  She and her calf Sick Joey (left) have been sighted in the Marco River, but never further south in Factory Bay or on the other Side of the Jolly Bridge.  Her Area One sightings skew further north on the intercoastal.  And in two exploratory trips taken into Area Three, she was in the Gorden Pass up in Naples twice.

 Just as KayCee’s sighting history suggests that the heart of her range lies to the north of the Area One transect, Crusty’s suggests that hers lies to the south.  She too has been seen in the Marco River, but in five years and over a thousand surveys she has never been seen in the intercoastal waterway north of Marco Island.  She has, on the other hand been seen to the south, in Factory bay.  And, during surveys in Area Two, she has been spotted three times on the southern end of Marco Island in Caxambas Pass.

 

As I compile a list of the community of dolphins whose range overlaps with the Area One transect, I will include both KayCee and Curley, based on the frequency of sightings and the number of other dolphins in the community with whom they have been sighted.

 

Disastre is another story.   Besides only having been seen in Area One only three times in five years, Disastre has only associated with 7 other Area One dolphins.  Compare this with 65 associates for Halfway, 38 for crusty and 16 for KayCee.  

 

There is a third reason not to consider Disastre as a member of the community of dolphins that inhabits Area One.  While the heart of KayCee and Crusty’s range clearly lies to the north and south of area 1, their sightings all fall either in the passes (Caxambas Pass, Big Marco Pass, Gordon Pass) or waters behind barrier Islands such as the Factory Bay and the intercoastal.  Disastre on the other hand, besides his exceedingly infrequent forays into the Marco River and Factory Bay, has been sighted most often in the near shore waters of the open Gulf in Area Two.  While this is a subject for another essay, those dolphins seen on Area Two trips along the coast (or area 1 trips that dip out into the open gulf briefly) seem almost never to venture further into the estuary and clearly represent a distinct community.  So for the purposes of this analysis, Disastre will be considered an Area Two dolphin and his sightings in area 1 will be considered a sort of incursion.

 

Finally before we move on to establish the make-up of this community of Area One dolphins we should include an example of a dolphin whose range falls just outside of Area One.  In the same sighting that found KayCee in the Gorden River in Naples, a dolphin named MissD was observed.   This dolphin has never been sighted in even the northernmost point of Area One.   

 

So, given the judgment calls implied by the preceding examples and recognizing that the home range of individual dolphins (and hence the boundaries of their communities) overlap, following is a list of Area One dolphins, divided by status and, where possible, gender.

                                       ADULT FEMALES                           19                      

             HALFWAY*        DARWINA*         NIBBLES*                            GIZA*

             TRIGGER          AVERY*               BOOTSTRAP BILL*            RANGLE*

             SYDNEY*            SPARKLE*          TATTOO*                             PATCH'S TWIN*

             SPARKY*            VICTORIA*         CAPTAIN HOOK*                 TESS*

             KAYCEE*             PAYTON*            CRUSTY*

                 *currently with calves

 

                                        ADULT MALES                        21

           C.U. JIMMIE               FLAG                     SHARKS               TRIXIE

           SUTILE*                      TUCKER                OSCAR                 CAPTAIN JACK

 

           BANGLE                      CALAMITY            MARCO                SCOOP

           FINCH                         AJAX                    SEASTAR             JINGLE

 

           SPIKE                         CAPRI                  INTRUDER          DESMOND

           PATCH*                      HATCHET 

                                                                           CAM

Spacing indicates strong association indicative of pair bonding

*no longer seen 

 

                                      CALVES                                    16 

 

                 GUMBO              AUBREY          JING JING           ANGEL               HILTON

                DOUBLE DIP      DESTINY         NADINE               SLICK JOEY      STAR  

                MOCHA              CAMERON        KEEGAN*            KAYA*              JAYSON          

                FLIPPER

               *young of year

                                                               

                                YOUNG SUB-ADULTS                      10

 

                SIMON       BABY BLUE       ORANGE       LUCKY CHARM       SEYMOUR

                RIPPLE      SINTAS              STELLAR       EL TERRIBLE          FARKLE

 

                                 OLDER SUB-ADULTS                        7

                MAMAWANE             BUTTON             BATMAN             ROCKY             RAKES        

                ELLIE MAY                KONA 

 

                           DOLPHINS NO LONGER SEEN

 

                PATCH                   SUTILE                   F.BACON            FARKLE*           FENDER           

                PINTA+                 BUTTERMILK+       GUS*                  HOPPY+          MR. CLEAN*

                EL TERRIBLE*        EL DUKE*               BABY TATTOO    SPARK+           SHERA++

                NOTCH

                 *clean fin (difficult to distinguish)   +deceased   ++probably deceased

You will want to know how I arrived at these conclusions.

 

The designation of adult females is based entirely on observing them in long term associations with a calf or, in some cases calves (Halfway has cared for three calves during the period we have observed her).

 

The designation of Adult males is based in part on size but also on association patterns consistent with male pair bonds or alliances as described by the folks at the SDRP.*  We always see these paired males together and often escorting one of the females in the area.  Hatchet and Capri were borderline: their association patterns suggest and incipient male alliance but they are more frequently seen with other adult males and rarely with any of the females in the population.  I imagine them as on the cusp of adulthood but still too young to be players in the mating game but that may be exactly wrong.

 

The young sub-adults were all still calves in close association with their mother when we first encountered them and given that both the research at the SDRP and our own observation suggests that calves remain with their mothers for three and five years, I am assuming that these recently emancipated sub-adults are around seven years or younger.

 

The list of older sub-adults involves more guess work and is based partly on size and partly on association patterns: they spend a lot of time together socializing as a group and their association with others is all over the board.

 

Those dolphins designated as deceased are calves that did not survive their first year of life.  In only one case did we actually see a dead dolphin, the rest were assumed to be dead when their mothers were sighted without them.  Several of the dolphins that we have lost track of had pretty clean fins when they became sub-adults making continued tracking difficult.  We’re getting better at this.

 

So that is the picture of Area 1 so far.  New surveys occurring now in adjacent areas will extend the range of many of its dolphins and undoubtedly alter our understanding of this ‘mosaic of …overlapping communities.’

 

*For  insights into bottlenose dolphins from their forty plus years of research see

 Reynolds, John E., Randall S. Wells, Samantha D. Eide.  2000. The Bottlenose Dolphin: Biology and Conservation. Gainesville, FL: University of Florida Press

 or check out their website:     http://www.sarasotadolphin.org/