Capricorn-Curtis coast Inshore Dolphins Project
Project Overview
This study is the father of the Capricron Cetaceans Research Project. Started in 2006 as a simple study on distribution and abundance and conservation status of Indo-Pacific humpback and Australian snubfin dolphins along the Capricorn Coast, the Capricorn Coast Inshore Dolphins Project embraced through the years a more multidisciplinary research approach to ehance our understanding on the connetiveness among populations and how that may affect the conservation status of inhore dolphins. To achieve these aims, data on genetics and distribution were used to identify potential management units, while data on abundance and habitat use were used for the assessment of the conservation status of both species against the IUCN Red List criteria for regional population. This project was completed in 2009.
This project was funded from the Fitzroy River Basin Association and Southern Cross University. Daniele Caganzzi was the primary investigator of this project under the supervision of Professor Peter Harrison from Southern Cross University and with the collaboration for the genetic of Dr Michael Kruetzen, from the University of Zurich.
Project Background
Indo-Pacific humpback and Australian snubfin dolphins in Queensland and Australia remains poorly known. National assessement of the conservation status of both species is currently hindered by the lack of dettailed information from most of their range. Prior to this study no pubblished information was available on inshore dolphins from this region. The occurrence of both species in this region was known only from local knowledge. For the purpose of this study, the Capricorn Coast was sub-divided into three main surveys areas: Port Curtis, Keppel Bay and Shoalwaterbay Military Area. In each of these area dedicated boat based surveys were conducted througout the year from 2006 to 2008 following standard procedures for inshore dolphins surveys. After a school of dolphins was sighted, dolphins were approached slowly to collect photo-dentification data (Nikon D100+80-400 Nikkor lens), date, time, geographical location, water depth, school size and age composition. Biospy samples were also collected using PAXARMS a biospy dart system especially designed to collect skin samples from dolphins.
Project objectives:
1) To investigate the occurrence and spatial distribution.
2) To asess social structure and to define home range and habitat preferences.
3) To investigate genetic population structure.
4) To obtain accurate population estimates
5) To assess the conservation of humpback and snubfin dolphins in the Capricorn Coast Region against the IUCN Red List Criteria.
Summary of the major findings
This study examined populations of Australian snubfin dolphins (Orcaella heinsohni) and Indo-Pacific humpback dolphins (Sousa chinensis) inhabiting the coastal waters of the Capricorn Section of the Great Barrier Reef Marine Park, Queensland, Australia. A total of 189 humpback dolphins and 64 snubfin dolphins were identified during 1,760 hours and 20,248 kms of transect surveys completedbetween 2006 and 2008 in the Capricorn Coast region. Humpback dolphins were found troughout the region but were primarily concentrated in three different sites: Port Curtis, Keppel Bay and Shoalwater Bay. In contrast, snubfin dolphins were found only in the Keppel Bay study area. Both humpback and snubfin dolphins were found year round with no significant variation among sampling periods and between seasons. Similarly, no substantial variation was found in pod size and composition among sampling periods and seasons.
Based on the distribution of resighted individuals and the pattern of associations, it was established that humpback dolphins in the Capricorn Coast were grouped into three largely geographically distinct communities, referred to as the Port Curtis, Keppel Bay and the Northern Region communities. The interaction recorded among communities was lower than the level of association within communities. However, interaction among some members of different communities and movement of individuals between sites was recorded.
Analysis of molecular variance showed high moderately low gene flow among Port Curtis and Keppel Bay study sites, which corroborates results from photo-identification data and social structure analysis. Extremely low gene flow was found between humpback dolphin populations from the Capricorn Coast and the Great Sandy Strait in the south, and Clevelnad Bay in the north which suggests that humpback dolphins from the Capricorn Coast form a separate management unit.
Abundance of humpback dolphins was estimated for the entire populationand by geographical area using open population models. Estimates for Port Curtis, Keppel Bay and the Northern Region indicate that about 85, 115 and 64 humpback dolphins used those areas respectively during the study. The total number of humpback dolphins along the Capricorn Coast region was estimated to be of about 256 individuals.
In contrast, snubfin dolphins were found only in Keppel Bay. This population appears to be geographically and demographically isolated. Genetic evidence based on a small sample size suggests that this population is genetically isolated from populations in North Queensland. A review of sighting information indicates that the Keppel Bay snubfin dolphin population is the southernmost population of snubfin dolphins along the Queensland coast. Population estimates indicate that about 80 snubfin dolphins live year round in Keppel Bay.
This study is the father of the Capricron Cetaceans Research Project. Started in 2006 as a simple study on distribution and abundance and conservation status of Indo-Pacific humpback and Australian snubfin dolphins along the Capricorn Coast, the Capricorn Coast Inshore Dolphins Project embraced through the years a more multidisciplinary research approach to ehance our understanding on the connetiveness among populations and how that may affect the conservation status of inhore dolphins. To achieve these aims, data on genetics and distribution were used to identify potential management units, while data on abundance and habitat use were used for the assessment of the conservation status of both species against the IUCN Red List criteria for regional population. This project was completed in 2009.
This project was funded from the Fitzroy River Basin Association and Southern Cross University. Daniele Caganzzi was the primary investigator of this project under the supervision of Professor Peter Harrison from Southern Cross University and with the collaboration for the genetic of Dr Michael Kruetzen, from the University of Zurich.
Project Background
Indo-Pacific humpback and Australian snubfin dolphins in Queensland and Australia remains poorly known. National assessement of the conservation status of both species is currently hindered by the lack of dettailed information from most of their range. Prior to this study no pubblished information was available on inshore dolphins from this region. The occurrence of both species in this region was known only from local knowledge. For the purpose of this study, the Capricorn Coast was sub-divided into three main surveys areas: Port Curtis, Keppel Bay and Shoalwaterbay Military Area. In each of these area dedicated boat based surveys were conducted througout the year from 2006 to 2008 following standard procedures for inshore dolphins surveys. After a school of dolphins was sighted, dolphins were approached slowly to collect photo-dentification data (Nikon D100+80-400 Nikkor lens), date, time, geographical location, water depth, school size and age composition. Biospy samples were also collected using PAXARMS a biospy dart system especially designed to collect skin samples from dolphins.
Project objectives:
1) To investigate the occurrence and spatial distribution.
2) To asess social structure and to define home range and habitat preferences.
3) To investigate genetic population structure.
4) To obtain accurate population estimates
5) To assess the conservation of humpback and snubfin dolphins in the Capricorn Coast Region against the IUCN Red List Criteria.
Summary of the major findings
This study examined populations of Australian snubfin dolphins (Orcaella heinsohni) and Indo-Pacific humpback dolphins (Sousa chinensis) inhabiting the coastal waters of the Capricorn Section of the Great Barrier Reef Marine Park, Queensland, Australia. A total of 189 humpback dolphins and 64 snubfin dolphins were identified during 1,760 hours and 20,248 kms of transect surveys completedbetween 2006 and 2008 in the Capricorn Coast region. Humpback dolphins were found troughout the region but were primarily concentrated in three different sites: Port Curtis, Keppel Bay and Shoalwater Bay. In contrast, snubfin dolphins were found only in the Keppel Bay study area. Both humpback and snubfin dolphins were found year round with no significant variation among sampling periods and between seasons. Similarly, no substantial variation was found in pod size and composition among sampling periods and seasons.
Based on the distribution of resighted individuals and the pattern of associations, it was established that humpback dolphins in the Capricorn Coast were grouped into three largely geographically distinct communities, referred to as the Port Curtis, Keppel Bay and the Northern Region communities. The interaction recorded among communities was lower than the level of association within communities. However, interaction among some members of different communities and movement of individuals between sites was recorded.
Analysis of molecular variance showed high moderately low gene flow among Port Curtis and Keppel Bay study sites, which corroborates results from photo-identification data and social structure analysis. Extremely low gene flow was found between humpback dolphin populations from the Capricorn Coast and the Great Sandy Strait in the south, and Clevelnad Bay in the north which suggests that humpback dolphins from the Capricorn Coast form a separate management unit.
Abundance of humpback dolphins was estimated for the entire populationand by geographical area using open population models. Estimates for Port Curtis, Keppel Bay and the Northern Region indicate that about 85, 115 and 64 humpback dolphins used those areas respectively during the study. The total number of humpback dolphins along the Capricorn Coast region was estimated to be of about 256 individuals.
In contrast, snubfin dolphins were found only in Keppel Bay. This population appears to be geographically and demographically isolated. Genetic evidence based on a small sample size suggests that this population is genetically isolated from populations in North Queensland. A review of sighting information indicates that the Keppel Bay snubfin dolphin population is the southernmost population of snubfin dolphins along the Queensland coast. Population estimates indicate that about 80 snubfin dolphins live year round in Keppel Bay.