Introduction
One of the core activities of the Dragon Search project is distribution and collection of Seadragon Sighting Forms, which allows people who encounter seadragons to record a number of parameters associated with the sighting (see Seadragon Sighting Form page). These forms are distributed to the public through dive shops and clubs, community groups, the Dragon Search website and the Dragon Search Project Officer. An estimated 2,000 of the 1999 edition of the Dragon Search Sighting Form have been distributed to the public in New South Wales (NSW).

In June 2000, Dragon Search (NSW) submitted a database containing the first 341 sightings to marine scientist Janine Baker for analysis. These sighting covered the period form January 1998 to June 2000. This document is a summary of that analysis. Additional comments have been added to provide background information.

Whilst the data in this report appears to confirm several points about weedy seadragons in NSW, as well as present some interesting trends, no conclusions have been drawn from the information collected so far. Further and more detailed monitoring of this enigmatic species is required to confirm it’s basic habits and ecology.

Each seadragon sighting is assigned three codes to identify the location of the sighting: Bioregion (see Section 2: Distribution for more information); Marker (the general region of the sighting, such as Jervis Bay); and Location (the area of the sighting).

Whilst reading this report, it is important to distinguish between number of sightings and number of seadragons sighted. The former encompasses all information recorded on a single Sighting Form, and thus may include more than one seadragon.

For more information contact:

Dragon Search NSW Project Officer
c/- UTS (CSB)
Westbourne Street
St Leonards NSW 2065
Phone: 02 9436 0176
Email: [email protected]
 
 
 

The Weedy Seadragon
The weedy seadragon (Phyllopteryx taeniolatus) and the leafy seadragon (Phycodorus eques) are members of the family Syngnathidae, which also includes seahorses and pipefish. Syngnathid means literally ‘tube-snouted’ in Latin, and refers to the long slender mouth common to these species. Of the 220+ Syngnathid species found worldwide, there are only the two species of seadragon, and both are found only in Australia.

Weedy seadragons inhabit shallow coastal waters from Geraldton in Western Australia to Newcastle on the central NSW coast, as well as Tasmania. They are very brightly coloured, generally being red to orange, with blue stripes and white spots, and grow to about 45 centimetres in length.  Seadragons feed on plankton, larval fish and small shrimp-like crustaceans called mysids.

The weedy seadragon is fully protected in NSW under the Fisheries Management Act 1994. Additionally all Syngnathids in Australia fall under the Commonwealth Wildlife Protection Act, requiring special permits for their export. The World Conservation Union (IUCN) lists weedy seadragons as data deficient, meaning that insufficient information is available to make an assessment of the species’ risk of extinction.
 

1. Distribution
There are five marine bioregions in New South Wales: Twofold Shelf, which extends south from Tathra into Victoria; Batemans Shelf, covering the area between Tathra and Shellharbour; Hawkesbury Shelf, covering the area between Shellharbour and Newcastle; Manning Shelf, covering the area between Newcastle and Nambucca Heads; and Tweed-Moreton, extending north of Nambucca Heads.

During the Dragon Search program in New South Wales, weedy seadragons have been recorded from three bioregions; Twofold, Batemans and Hawkesbury Shelves. The total number of sightings from January 1998 to June 2000 was 341, a total of 1001 seadragons.

74% of sightings (79% of total seadragons sighted) have come from locations in the Hawkesbury Shelf bioregion; 20% of sightings (12% of total seadragons sighted) from the Batemans Shelf bioregion; and 6% of sightings (9% of total seadragons sighted) from the Twofold Shelf bioregion.
 

No seadragons have been recorded by Dragon Search NSW from the Manning Shelf or the Tweed-Moreton Bioregions. The most northerly sighting was at Swansea on the Central Coast, the most southerly at Twofold Bay. No leafy seadragons have been recorded by Dragon Search NSW, hence all references to ‘seadragons’ in this report refer to weedy seadragons.

The tables below summarise the main locations in which divers have sighted seadragons (including repeat sightings at the same location).
 

In the Hawkesbury Bioregion, 76% of the sightings have been recorded from the Botany Bay area. Around Botany Bay, the majority of sightings (97%) have come from Kurnell and Bare Island (including repeat sightings). Around Sydney Harbour, 58% of sightings to date have come from South Head, and 73% of sightings in the Manly area have been recorded in waters off Shelley Beach. Half of the sightings in the Cronulla area have come from Bate Bay. Amongst the sightings from the Wollongong area is a record of 20 adult seadragons sighted together in January 1999.
 

Almost 39% of the sightings from the Jervis Bay area were recorded from Bowen Island, and around a third of the sightings were recorded from The Docks. In the Shellharbour area, around 82% of sightings came from Bass Point.

Of the sightings from the Twofold Bay area in southern New South Wales, 4 sightings each have been recorded from Edrom Beach and Fisheries Beach.

Note that relative numbers of seadragons at each location cannot be determined, due to the non-systematic nature of Dragon Search sightings, which are influenced by diver preferences regarding choice of dive site; accessibility of dive site; and other factors. Similarly, it is not possible to determine the proportion of sightings per location that are repeat sightings of the same animals or groups of animals. Despite these caveats, it is clear from the available data that seadragons are relatively abundant in the Botany Bay area, with single sightings and groups of adults (from 2 to 21 individuals) being recorded every year from the mid 1990s to the present.

The relatively small number of records from southern areas of the state does not necessarily indicate that sea dragons are less abundant at some locations in those areas, compared with more accessible sites. The paucity of sightings in such areas may reflect the smaller number of dives that have taken place in more remote areas compared with popular dive sites in more accessible locations, near large population centres, and/or at sites where the Dragon Search NSW project is more heavily promoted, or is better known to the diving community.
 

2. Sighting Details
(i) Seasonal Summary of Sightings: Figure 1 below shows a monthly summary of seadragon sightings to June 2000. Around one third of sightings were made during the summer months. Between 23% and 24% of sightings were made during spring and autumn, and 19% of sightings occurred during the winter months. Neither relative frequency nor seasonal abundance of seadragons per sighting location can be meaningfully discussed due to the non-standardised nature of the recording, which is affected by a number of factors. These include (i) uneven distribution of recordings over space and time; (ii) individual preferences in the locations and seasons in which recorders chose to dive or beach-walk, (iii) weather and/or sea conditions, and (iv) other opportunistic and/or uncontrollable aspects of the recordings. However, monthly distribution of seadragon sightings provides important supporting information when assessing seasonality of breeding, as discussed in the section below on Brooding Male Seadragons.
 

(ii) Summary of Sighting Modes: To date, around 79% of seadragon sightings have been recorded by SCUBA divers (= 86% of total number of seadragons sighted, representing 866 seadragons sighted by SCUBA divers); 18% have been records of dead seadragons sighted by beachcombers (7% of the total number of seadragons sighted), and 1% each of sightings have been recorded during snorkelling (5 records; 14 seadragons), or night diving (4 records; 48 seadragons). To date, 43% of dive sightings have come from the Botany Bay area; 12% from Jervis Bay; 8% from the Shellharbour and Wollongong area; 6% from Sydney Harbour, and 3% from Bondi.

3. Habitat Preference
To date, habitat type has been specified for 78% of all sightings. Although there appears to be some lack of standardisation in the recording of habitat details, notable results to date include:
• The relatively low incidence of sightings over seagrass habitat (12% of sightings, and representing 143 seadragons), compared with rocky reef and macroalgal-dominated habitats. This is noteworthy, due to the regularity of reports in popular articles throughout the 1990s that seadragons are mainly found in seagrass habitat.
• The relatively high incidence of sightings (39% of sightings, and representing 282 seadragons) over macroalgal-dominated habitat, which might reflect lack of food availability over bare substrate, and/or these seadragons' habitat preference for vegetation as a means of camouflage;
• The similar incidence of sightings over reef of unspecified cover (21%, representing 185 seadragons), and over sand and/or rubble habitats for which no cover was specified (19% of sightings, representing 210 seadragons). It is not possible to determine from available data the proportion of sightings that occurred over bare sand or rubble (compared with the omission by recorders of additional habitat details for these substrate types);
• The incidence of seadragons over sponge-dominated habitat (7% of habitat recordings, and representing 75 seadragons), which appears to not be commonly known as a habitat type in which seadragons are found.

Feeding behaviour was observed in 7 sightings (representing 28 seadragons), and the recorded habitat for 6 of those 7 sightings was reef, with kelp, sponge cover, or unspecified cover. One sighting of 10 seadragons (including 4 juveniles) had sand recorded as the habitat, with no other details provided.
 

4. Behaviour
To date, 1001 seadragons have been recorded during the Dragon Search NSW project and related sightings. Of these animals sighted, 46% have been recorded as hovering or resting, 34% were recorded as swimming, almost 3% feeding, and 13% were recorded as being engaged in other behaviours/activities, including 4% (from a single sighting) recorded as engaging in mating behaviour. Habitat details are provided for observations of feeding seadragons in the section above on Habitat Preference.  It is noted that mating behaviour was recorded for a single “mass” sighting of 40 seadragons, although all were reported to be males. Although only 9% of seadragons observed were reported to be engaging in behaviours other than those listed on the Dragon Search form, this represented 22% of the total number of sightings. There was no recording of behaviour for 3% of seadragons sighted.
 

5. Seadragon Groups
To date, 40% of weedy seadragon dive sightings have been of single animals. However, groups of seadragons have been found in the majority of siting locations recorded in the Dragon Search NSW database.  The Table 7 summarises the locations of records of seadragon group sightings, from 2 to 40 animals.

To date, 25 separate sightings of groups comprising between 6 and 21 animals have been recorded in the Hawkesbury Bioregion, particularly from Kurnell, near the entrance to Botany Bay. Large groups of seadragons (e.g. 10 to 20 animals) have been observed in all seasons of the year from the Hawkesbury Shelf Bioregion.

In the Batemans Shelf Bioregion, groups of between 6 and 10 animals have been observed at several locations around Jervis Bay. The largest group observation recorded to date comes from an old pre-Dragon Search NSW record from Edrom Beach near Twofold Bay, in the Twofold Shelf Bioregion, where 40 male seadragons (including 20 brood males) were apparently sighted during a night dive in the summer of 1984.  Fewer group sightings have occurred in the Twofold Shelf Bioregion compared with the two bioregions to the north.

It is not possible to determine from available data whether any group sightings are repeat sightings of the same group. However, it is noted that in some instances, groups comprising different numbers of animals have been observed in the same location within a 30 day period. A few examples would include groups of 3 seadragons and 10 seadragons at Jervis Bay; groups of 5 seadragons and 12 seadragons, and groups of 7 and 19 seadragons, at Botany Bay. This provides some indirect evidence that different groups (or at least different animals within the same loosely structured groups) are being observed at some of these locations, and that repeat sightings of the same groups of animals are not necessarily being made in all circumstances.  Smaller groups (3 to 5 animals) of seadragons have been observed from more than 20 different locations, covering all three bioregions. To date, 21% of the weedy seadragon dive sightings have been of pairs.
 

6. Brooding Male Seadragons
(i) Statewide
Brooding male seadragons were sighted from mid winter to mid summer (Figure 3) throughout New South Wales. For example, at a statewide level, with data pooled for all years, 45 individual sightings were made between the months of July and January, representing 75 brooding males.  Brooding males have been recorded at depths ranging from 4m to 27m. More than half of the total number of brood male sightings occurred during late spring to early summer (October to December.) No sightings of brooding males were made during dives from February to June.  It can be inferred from available data that the statewide breeding season in New South Wales ranges from mid winter to summer. The inference that brooding does not occur during autumn to early winter is supported by the fact that 36% of all seadragon sightings occurred during February to June, representing 351 seadragons (see Figure 1), but no breeding males were observed during sightings in those months.
 

(ii) Bioregional:
In the Hawkesbury Shelf Bioregion, brooding male seadragons have been observed from mid winter (July) through to mid summer (January), and at locations Batemans Shelf Bioregion from spring (September) through to mid summer (January). Interestingly, brooding males have been observed during the winter months of July and August in the Botany Bay area, in 1996, 1998 and 1999.  In the Twofold Shelf Bioregion of New South Wales, sightings of brooding males occurred only during early summer (December), including one record of 20 brooding males observed (apparently in an aggregation with 20 non-brooding males). Due to the unstandardised nature of Dragon Search recordings, and the small number of records from the Twofold Shelf Bioregion, it is not possible to conclude from the available data that seadragons enter their breeding and brooding phase later in the year in the more-southerly waters. However, available sighting data suggests that this may be the case, and more records from southern locations in New South Wales would lend support to this conjecture.  The table below summarises sightings of brood male seadragons on a bioregional basis. The largest number of sightings of single brooding male seadragons has come from Kurnell, in the Botany Bay area.
 

7. Juvenile Seadragons
The largest number of juvenile seadragons observed together comes from the Swansea area, in the Hawkesbury Bioregion, where 17 juveniles were observed hovering together during a March 2000 dive. The table below summarises sightings of “family groups” of adult and juvenile seadragons observed together.  Approximately two thirds of observations of juvenile seadragons have comprised a single juvenile animal. In the Hawkesbury Shelf Bioregion, groups of juveniles have been observed swimming and hovering with adults at (i) Kurnell, Botany Bay, particularly during 1999 and 2000; (ii) Shelley Beach, Manly, in 1998; and at sites near Terrigal and Catherine Hill Bay, in 1997 and 1999, respectively. Observed “family groups” have been particularly large at the Kurnell site (e.g 15 adults with 4 juveniles; 8 adults with 4 juveniles; 16 adults with two juveniles). In the Batemans Shelf Bioregion, groups of juveniles and adults have been observed at sites around Jervis Bay, during sightings in 1996 and 1999.  The table below provides a summary of the number of adults and juveniles observed swimming, hovering, or feeding together.

According to available records (35 sightings), there appears to be no seasonal pattern to the sightings of juvenile seadragons. Juveniles have been sighted in all months of the year in New South Wales. It is noted that 43% of the total number of juveniles observed (69 seadragons), were sighted during early to mid autumn.  A size of less than 20cm is stated by the Dragon Search program as a guide to identifying juvenile seadragons. However, some of the records may be of small adults or young adults, and some might include misjudgments of size by recorders, which might explain the lack of seasonality of the juvenile sightings. Due to the opportunistic nature of the Dragon Search sightings, and the lack of standardisation between months regarding the distribution and frequency of recordings, available data (to date) cannot be used to determine in which season juveniles are more abundant.
 

8. Beachwashed Seadragons
To June 2000, 63 sightings of beached seadragons have been recorded, comprising a total of 75 specimens. Thirty four percent of all sightings occurred during the summer months, 32% during autumn, 10% during winter, and 24% during the spring months. To date, almost 80% of beachwash sightings have been of  "freshly dead" seadragons. "Fresh" dead seadragons refer to recent beachwashed specimens which are not shrunken or dried, are still colourful, and usually still have the appendages intact. "Old" specimens refer to dried, shrunken and/or decomposing seadragons.  Single specimens of live beached seadragons have been recorded from Harboard, Catherine Hill Bay, Narrabeen, Newport, and Austinmer Beach.  Most beached seadragon sightings occurred between 1995 and 2000, but it is noted that several early pre-Dragon Search NSW records exist in the database, including sightings from Palm Beach (in 1952) and Warilla (1985).

Beachwashed seadragons have been recorded from 45 locations along the New South Wales coast. The greatest number of dead weedy seadragon sightings from single localities have been from the Mona Vale area (total of 7 seadragons); the Narrabeen area, including Collaroy Beach and Narrabeen Headland (6 seadragons); Austinmer Beach (5 seadragons); sites near Thirroul, Moruya and Palm Beach (4 seadragons each); and the Wollongong area (3 seadragons). To date, no “mass mortality” events have been recorded in the Dragon Search NSW database.
 

9. Depth of Sightings and Water Temperature
The number of sightings reported at each depth, showing a recorded range of 1m to 27m for dive sightings, is shown below. A large proportion (63%) of sightings was recorded in middle depths (12m to 20m) within the range extremes. A similar proportion (66%) of the total number of seadragons sighted, was recorded in these middle depths.
 

The available data cannot be used to infer that seadragons are more abundant in the teen depths compared with single figure depths or those greater than 20m, due to the non-systematic nature of the recordings, which are influenced by diver preferences. Depth range per month, not presented here, showed no seasonal pattern. Little can be inferred about seasonal depth variations in seadragon distribution from available data. Several reasons include the fact that

(i) the number of sightings recorded per month is opportunistic, according to diver preferences;
(ii) the survey was not standardised: i.e. seadragons were not searched for, at specific depths, in every month; and
(iii) the uneven numbers of records between months influences the depth range of the sightings that are recorded in each month (for some months, seadragons may be found at other depths that have not recorded due to the smaller number of records available for those months).

Other influences include possible depth gauge inaccuracies on divers' watches, and the fact that in some parts of the state, sighting depths are influenced by the depth of features at preferred dive locations, such as depth of reef patch. That is, sea dragons may be found at other depths in the vicinity, but such depths were not surveyed because they did not contain the feature of dive interest.

Similar caveats apply to the interpretation of temperature recorded during seadragon sightings, particularly due to the prevalence of summer diving (i.e. pleasant diving conditions), and the under-representation of winter sightings. However, one notable result from these data is the recorded temperature range for sightings, which, to date, has ranged from 14^oC to 24^oC. Within that range, 83% of sightings for which temperature was recorded (252 sightings), were made in waters between 16^oC and 21^oC.
 

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